ABSTRACT

BILGEN, MUSTAFA. Wrinkle Recovery for Cellulosic Fabric by Means of Ionic Crosslinking. (Under the direction of Peter Hauser and Brent Smith.)

When treated with formaldehyde-based crosslinkers, cellulosic fabrics show

improved mechanical stability, wrinkle recovery angles and durable press performance,

but N-methylol treatment also causes fabrics to lose strength and later to release

formaldehyde, a known human carcinogen. We have discovered that ionic crosslinks can

stabilize cellulose using high or low molecular weight ionic materials which do not release

hazardous reactive chemicals, but at the same time provide improved wrinkle recovery

angles as well as complete strength retention in treated goods. We have varied

polyelectrolyte, the ionic content of fabrics, and various features of the application

procedure to optimize the results and to develop an in-depth fundamental physical and

chemical understanding of the stabilization mechanism.

WRINKLE RECOVERY FOR CELLULOSIC FABRIC BY MEANS OF IONIC CROSSLINKING

by

MUSTAFA BILGEN

A thesis submitted to the Graduate Faculty of North Carolina State University

in partial fulfillment of the requirements for the Degree of

Master of Science

TEXTILE CHEMISTRY

Raleigh

2005

APPROVED BY:

Dr. Peter Hauser (Chair) Dr. Brent Smith (Co-Chair)

Dr. Charles Boss (Minor)

ii

DEDICATION

This thesis is dedicated to my family and my wife, Nicole, who supported me with

constant love and caring and inspired my interest in studying textile chemistry.

iii

BIOGRAPHY

Mustafa Bilgen was born in December 1, 1978 in Erdemli, Turkey. He graduated

from Erzurum Science High School in June 1995. He received the Bachelor of Science

degree in Textile Engineering from Department of Engineering and Architecture, Uludag

University, Bursa, Turkey in July 1999.

After he graduated he worked as a dyeing and finishing supervisor in Akay Textile

Dyeing & Finishing Company for one year before he started to help his father for taking

care of the family business.

He came to North Carolina State University in January 2004, to continue his education

and started his master program in Textile Chemistry under the direction of Dr. Brent

Smith and Dr. Peter Hauser.

iv

ACKNOWLEDGEMENTS

I would like to thank to the National Textile Center and North Carolina State University

for their financial support. I also would like to thank to my advisors, Dr. Hauser and Dr.

Smith, for their crucial help and patience during my research and preparation of my thesis.

v

LIST OF CONTENTS

LIST OF TABLES ------------------------------------------------------------------------------- viii LIST OF FIGURES --------------------------------------------------------------------------------x 1. INTRODUCTION -------------------------------------------------------------------------------1 2. LITERATURE REVIEW ----------------------------------------------------------------------3

2.1 Cellulose chemistry ---------------------------------------------------------------------------3 2.2 Cellulosic fabric’s nature of wrinkling -----------------------------------------------------5 2.3 Durable Press finishing of cotton -----------------------------------------------------------6

2.3.1 Urea-Formaldehyde derivatives--------------------------------------------------------7 2.3.2 Melamine-Formaldyhe derivatives ----------------------------------------------------7 2.3.3 Methylol derivatives of cyclic ureas --------------------------------------------------8 2.3.4 Effects of formaldehyde based DP finishes on cellulose ---------------------------9

2.4 Recent developments in non-formaldehyde DP applications ------------------------- 10 2.5 Ionic crosslinking --------------------------------------------------------------------------- 14 2.6 Preparation of quaternized polymers ----------------------------------------------------- 16

2.6.1 Chitosan and its reaction with CHTAC --------------------------------------------- 16 2.6.2 Reaction of Cellulose with CHTAC------------------------------------------------- 18

2.7 Carboxymethylation of cellulose---------------------------------------------------------- 20 2.8 Proposed Research-------------------------------------------------------------------------- 21

3. EXPERIMENTAL PROCEDURES ------------------------------------------------------- 23 3.1 Test Materials-------------------------------------------------------------------------------- 23 3.2 Equipments ---------------------------------------------------------------------------------- 25 3.3 Application procedures--------------------------------------------------------------------- 25

3.3.1 Pad dry cure ---------------------------------------------------------------------------- 25 3.3.2 Pad batch-------------------------------------------------------------------------------- 26 3.3.3 Exhaustion ------------------------------------------------------------------------------ 26

3.4 Analysis and physical property tests------------------------------------------------------ 26 3.4.1 Nitrogen analysis ---------------------------------------------------------------------- 27 3.4.2 FT-IR analysis-------------------------------------------------------------------------- 27 3.4.3 1H- NMR analysis --------------------------------------------------------------------- 27 3.4.4 Wrinkle recovery angles -------------------------------------------------------------- 28 3.4.5 Tensile strength ------------------------------------------------------------------------ 28 3.4.6 Whiteness index------------------------------------------------------------------------ 28 3.4.7 Stiffness --------------------------------------------------------------------------------- 28

3.5 Reaction of cellulose with chloroacetic acid -------------------------------------------- 29 3.6 Reaction of Cellulose with CHTAC------------------------------------------------------ 32 3.7 Synthesis of compounds ------------------------------------------------------------------- 35

3.7.1 Molecular weight determination of chitosan --------------------------------------- 35 3.7.2 Depolymerization of chitosan and characterization ------------------------------- 37 3.7.3 Reaction of chitosan with CHTAC -------------------------------------------------- 39 3.7.4 Reaction of glycerin and ethylene glycol with CHTAC -------------------------- 51

vi

3.7.5 Reaction of cellobiose and dextrose with CHTAC -------------------------------- 53 3.8 Preparation of fabric samples-------------------------------------------------------------- 53 3.9 Crosslinking of carboxymethylated cellulosic fabric----------------------------------- 54

3.9.1 Treatment with cationic chitosan ---------------------------------------------------- 54 3.9.2 Treatment with cationic glycerin ---------------------------------------------------- 54 3.9.3 Treatment with cationic cellobiose, cationic dextrose and cationic ethylene glycol------------------------------------------------------------------------------------------- 55 3.9.4 Treatment with calcium chloride and magnesium chloride ---------------------- 55

3.10 Crosslinking of cationic cellulosic fabric----------------------------------------------- 57 3.10.1 Treatment with PCA and BTCA --------------------------------------------------- 57 3.10.2 Treatment with EDTA, NTA and HEDTA --------------------------------------- 59 3.10.3 Treatment with oxalic acid, citric acid and malic acid -------------------------- 59

4. RESULTS & OBSERVATIONS AND DISCUSSION---------------------------------- 60 4.1 Wrinkle recovery angles of conventional durable press finished fabrics ------------ 60 4.2 Wrinkle recovery angles of polycation treated anionic cellulosic fabrics ----------- 60

4.2.1 Wrinkle recovery angles of cationic chitosan treated fabrics -------------------- 60 4.2.2 Application of paired t-test analysis on cationic chitosan treatments ----------- 68 4.2.3 Wrinkle recovery angles of cationic glycerin treatments ------------------------- 71 4.2.4 Wrinkle recovery angles of cationic cellobiose and cationic dextrose treated fabrics ------------------------------------------------------------------------------------------ 76 4.2.5 Wrinkle recovery angles of calcium chloride and magnesium chloride treated fabrics ------------------------------------------------------------------------------------------ 76 4.2.6 Discussion of wrinkle recovery angles for polycation treatments --------------- 79

4.3 Wrinkle recovery angles of polyanion treated cationic cellulosic fabrics ----------- 82 4.3.1 Wrinkle recovery angles of PCA and BTCA treated fabrics--------------------- 82 4.3.2 Wrinkle recovery angles of EDTA, NTA and HEDTA treated fabrics --------- 87 4.3.3 Wrinkle recovery angles of oxalic acid, citric acid and malic acid treatments 89 4.3.4 Discussion of wrinkle recovery angles for polyanion treatments---------------- 90

4.4 Strength data--------------------------------------------------------------------------------- 92 4.4.1 Tensile strength of conventional durable press finished fabric ------------------ 92 4.4.2 Strength data of polycation treated anionic cellulosic fabrics-------------------- 93 4.4.3 Strength data of polyanion treated cationic cellulosic fabrics-------------------- 96 4.4.4 Discussion of strength data of untreated and treated fabrics --------------------- 98

4.5 CIE whiteness index data -----------------------------------------------------------------101 4.5.1 CIE whiteness index of conventional durable press treated fabric -------------101 4.5.2 CIE whiteness index of polycation treated anionic cellulosic fabrics----------102 4.5.3 CIE whiteness index of polyanion treated cationic cellulosic fabrics----------104 4.5.4 Discussion of whiteness index of untreated and treated fabrics ----------------106

4.6 Stiffness data -------------------------------------------------------------------------------108 4.6.1 Stiffness of conventional durable press treated fabrics --------------------------109 4.6.2 Stiffness data of polycation treated anionic cellulosic fabrics ------------------109 4.6.3 Stiffness data of polyanion treated cationic cellulosic fabrics ------------------111 4.6.4 Discussion of stiffness data of untreated and treated fabrics--------------------113

vii

5. CONCLUSIONS ------------------------------------------------------------------------------116 6. RECOMMENDATIONS FOR FUTURE WORK--------------------------------------118 7. LIST OF REFERENCES--------------------------------------------------------------------121 8. APPENDIX-------------------------------------------------------------------------------------126

8.1 Wrinkle recovery angles ------------------------------------------------------------------126 8.2 Breaking strength --------------------------------------------------------------------------133 8.3 CIE whiteness index -----------------------------------------------------------------------137 8.4 Stiffness -------------------------------------------------------------------------------------141 8.5 Nitrogen analysis---------------------------------------------------------------------------145

viii

LIST OF TABLES

Table 3.2 Results for carboxymethylation of cellulosic fabrics ------------------------------ 32 Table 3.3 Scheme of intrinsic viscosity measurement for the low viscosity chitosan ----- 36 Table 3.4 Properties of the Low Viscosity chitosan.------------------------------------------- 37 Table 3.5 The intrinsic viscosity and Mv of depolymerized chitosans----------------------- 39 Table 4.1 Paired t-test results for dry wrinkle recovery angles of cationic chitosan treated

fabrics ------------------------------------------------------------------------------------------ 69 Table 4.2 Paired t-test results for wet wrinkle recovery angles of cationic chitosan treated

fabrics ------------------------------------------------------------------------------------------ 70 Table 4.3 Paired t-test results for dry/wet wrinkle recovery angles of Ca++ and Mg++

treated fabrics --------------------------------------------------------------------------------- 79 Table 4.4 Paired t-test results for dry/wet wrinkle recovery angles of PCA and BTCA

treated fabrics --------------------------------------------------------------------------------- 87 Table A.1 Dry and wet wrinkle recovery angles for molecular weight of 3.2 x 104g/mole

cationic chitosan treated fabrics -----------------------------------------------------------126 Table A.2 Dry and wet wrinkle recovery angles for molecular weight of 1.4 x 105g/mole

cationic chitosan treated fabrics -----------------------------------------------------------127 Table A.3 Dry and wet wrinkle recovery angles for molecular weight of 6.11 x 105g/mole

cationic chitosan treated fabrics -----------------------------------------------------------127 Table A.4 Dry and wet wrinkle recovery angles for molecular weight of 1.4 x 105g/mole

cationic chitosan treated fabrics by exhaustion method --------------------------------128 Table A.5 Dry and wet wrinkle recovery angles for cationic glycerin treated fabrics----128 Table A.6 Dry and wet wrinkle recovery angles for cationic glycerin treated fabrics by

exhaustion method---------------------------------------------------------------------------129 Table A.7 Dry and wet wrinkle recovery angles for cationic cellobiose and cationic

dextrose treated fabrics ---------------------------------------------------------------------129 Table A.8 Dry and wet wrinkle recovery angles for calcium chloride and magnesium

chloride treated fabrics ---------------------------------------------------------------------130 Table A.9 Dry and wet wrinkle recovery angles for PCA treated fabrics------------------130 Table A.10 Dry and wet wrinkle recovery angles for BTCA treated fabrics --------------131 Table A.11 Dry and wet wrinkle recovery angles for EDTA treated fabrics --------------131 Table A.12 Dry and wet wrinkle recovery angles for NTA treated fabrics ----------------132 Table A.13 Dry and wet wrinkle recovery angles for HEDTA treated fabrics ------------132 Table A.14 Dry and wet wrinkle recovery angles for oxalic, malic and citric acid treated

fabrics -----------------------------------------------------------------------------------------133 Table A.15 Breaking strength data for molecular weight of 3.2 x 104g/mole cationic

chitosan treated fabrics ---------------------------------------------------------------------134 Table A.16 Breaking strength data for molecular weight of 1.4 x 105g/mole cationic

chitosan treated fabrics ---------------------------------------------------------------------134

ix

Table A.17 Breaking strength data for molecular weight of 6.11 x 105g/mole cationic chitosan treated fabrics ---------------------------------------------------------------------135

Table A.18 Breaking strength data for cationic glycerin treated fabrics -------------------135 Table A.19 Breaking strength data for calcium chloride and magnesium chloride treated

fabrics -----------------------------------------------------------------------------------------136 Table A.20 Breaking strength data for PCA treated fabrics ---------------------------------136 Table A.21 Breaking strength data for BTCA treated fabrics -------------------------------137 Table A.22 Whiteness index data for molecular weight of 3.2 x 104g/mole cationic

chitosan treated fabrics ---------------------------------------------------------------------138 Table A.23 Whiteness index data for molecular weight of 1.4 x 105g/mole cationic

chitosan treated fabrics ---------------------------------------------------------------------138 Table A.24 Whiteness index data for molecular weight of 6.11 x 105g/mole cationic

chitosan treated fabrics ---------------------------------------------------------------------139 Table A.25 Whiteness index data for CG treated fabrics-------------------------------------139 Table A.26 Whiteness index data for calcium and magnesium chloride treated fabrics -140 Table A.27 Whiteness index data for PCA treated fabrics -----------------------------------140 Table A.28 Whiteness index data for BTCA treated fabrics---------------------------------141 Table A.29 Stiffness data for molecular weight of 3.2 x 104g/mole cationic chitosan

treated fabrics --------------------------------------------------------------------------------142 Table A.30 Stiffness data for molecular weight of 1.4 x 105g/mole cationic chitosan

treated fabrics --------------------------------------------------------------------------------142 Table A.31 Stiffness data for molecular weight of 6.11 x 105g/mole cationic chitosan

treated fabrics --------------------------------------------------------------------------------143 Table A.32 Stiffness data for cationic glycerin treated fabrics ------------------------------143 Table A.33 Stiffness data for calcium chloride and magnesium chloride treated fabrics 144 Table A.34 Stiffness data for PCA treated fabrics --------------------------------------------144 Table A.35 Stiffness data for BTCA treated fabrics ------------------------------------------145 Table A.36 Nitrogen analysis data for molecular weight of 3.2 x 104g/mole cationic

chitosan treated fabrics ---------------------------------------------------------------------146 Table A.37 Nitrogen analysis data for molecular weight of 1.4 x 105g/mole cationic

chitosan treated fabrics ---------------------------------------------------------------------146 Table A.38 Nitrogen analysis data for molecular weight of 6.11 x 104g/mole cationic

chitosan treated fabrics ---------------------------------------------------------------------147 Table A.39 Nitrogen analysis data for cationic glycerin treated fabrics--------------------147

x

LIST OF FIGURES

Figure 2.1 Molecular structure of a cellulose polymer chain -----------------------------------4 Figure 2.2 Crystalline and amorphous structure of cellulose -----------------------------------4 Figure 2.3 Molecular structure of DMDHEU-----------------------------------------------------8 Figure 2.4 Molecular structure of BTCA-------------------------------------------------------- 12 Figure 2.5 Reaction of chitosan with CHTAC in alkaline conditions ----------------------- 17 Figure 2.6 Reaction of cellulose with CHTAC in alkaline conditions----------------------- 19 Figure 2.7 Molecular structure of carboxymethyl cellulose ---------------------------------- 20 Figure 3.1 Reactions of cellulose with CAA that impart an anionic character ------------- 30 Figure 3.2 Reactions of cellulose with CHTAC that impart a cationic character ---------- 34 Figure 3.3 Huggins plot of ήsp/c versus c for the cationic chitosan -------------------------- 37 Figure 3.4 Reaction of chitosan with CHTAC-------------------------------------------------- 41 Figure 3.5 Conductometric titration curve of cationic chitosan ------------------------------ 43 Figure 3.6 FTIR spectrum of deacetylated chitosan ------------------------------------------- 46 Figure 3.7 FTIR spectrum of cationic chitosan------------------------------------------------- 47 Figure 3.8 1H-NMR spectrum of deacetylated chitosan --------------------------------------- 48 Figure 3.9 1H-NMR spectrum of O-substituted and N-substituted cationic chitosan ----- 50 Figure 3.10 Reaction of glycerin with CHTAC ------------------------------------------------ 52 Figure 3.11 Crosslinked anionic cellulose with calcium -------------------------------------- 56 Figure 3.12 Crosslinked cationic cellulose with BTCA --------------------------------------- 58 Figure 4.1 Effect of carboxyl content and concentration on dry wrinkle recovery angles of

cationic chitosan treated fabrics ------------------------------------------------------------ 62 Figure 4.2 Effect of carboxyl content and concentration on wet wrinkle recovery angles of

cationic chitosan treated fabrics ------------------------------------------------------------ 62 Figure 4.3 Effect of carboxyl content and concentration on %Nitrogen content of cationic

chitosan treated fabrics ---------------------------------------------------------------------- 64 Figure 4.4 The relationship between %Nitrogen content of the fabrics and dry/wet wrinkle

recovery angles ------------------------------------------------------------------------------- 65 Figure 4.5 Effect of molecular weight of chitosan and concentration on dry wrinkle

recovery angles of cationic chitosan treated fabrics ------------------------------------- 67 Figure 4.6 Effect of molecular weight of chitosan and concentration on wet wrinkle

recovery angles of cationic chitosan treated fabrics ------------------------------------- 67 Figure 4.7 Effect of carboxyl content and concentration on dry wrinkle recovery angles of

cationic glycerin treated fabrics ------------------------------------------------------------ 72 Figure 4.8 Effect of carboxyl content and concentration on wet wrinkle recovery angles of

cationic glycerin treated fabrics ------------------------------------------------------------ 72 Figure 4.9 Effect of carboxyl content and concentration on %Nitrogen content of cationic

glycerin treated fabrics----------------------------------------------------------------------- 74 Figure 4.10 The relationship between %Nitrogen content of the fabrics and dry/wet

wrinkle recovery angles --------------------------------------------------------------------- 75

xi

Figure 4.11 Effect of carboxyl content on dry wrinkle recovery angles of calcium and magnesium treated fabrics------------------------------------------------------------------- 77

Figure 4.12 Effect of carboxyl content on wet wrinkle recovery angles of calcium and magnesium treated fabrics------------------------------------------------------------------- 78

Figure 4.13 Effect of %Nitrogen fixed and concentration on dry wrinkle recovery angles of PCA treated fabrics ----------------------------------------------------------------------- 83

Figure 4.14 Effect of %Nitrogen fixed and concentration on wet wrinkle recovery angles of PCA treated fabrics ----------------------------------------------------------------------- 84

Figure 4.15 Effect of %Nitrogen fixed and concentration on dry wrinkle recovery angles of BTCA treated fabrics --------------------------------------------------------------------- 85

Figure 4.16 Effect of% Nitrogen fixed and concentration on wet wrinkle recovery angles of BTCA treated fabrics --------------------------------------------------------------------- 86

Figure 4.17 Effect of %Nitrogen fixed and concentration on dry wrinkle recovery angles of EDTA treated fabrics --------------------------------------------------------------------- 88

Figure 4.18 Effect of %Nitrogen fixed and concentration on wet wrinkle recovery angles of EDTA treated fabrics --------------------------------------------------------------------- 89

Figure 4.19 Effect of treatment on dry wrinkle recovery angles ----------------------------- 91 Figure 4.20 Effect of treatment on wet wrinkle recovery angles ----------------------------- 92 Figure 4.21 Effect of carboxyl content and concentration on breaking strength of the

cationic chitosan (molecular weight of 1.4 x 105g/mole) treated fabrics-------------- 94 Figure 4.22 Effect of carboxyl content and concentration on breaking strength of the

cationic glycerin treated fabrics ------------------------------------------------------------ 95 Figure 4.23 Effect of carboxyl content and concentration on breaking strength of the

calcium and magnesium treated fabrics --------------------------------------------------- 95 Figure 4.24 Effect of %Nitrogen content and concentration on breaking strength of the

PCA treated fabrics--------------------------------------------------------------------------- 97 Figure 4.25 Effect of %Nitrogen content and concentration on breaking strength of the

BTCA treated fabrics ------------------------------------------------------------------------ 97 Figure 4.26 Effect of treatment on breaking strength------------------------------------------ 99 Figure 4.27 Correlation between wet wrinkle recovery angles of cationic chitosan

(molecular weight of 1.4 x 105g/mole) treatment and tensile strength ---------------100 Figure 4.28 Correlation between wet wrinkle recovery angles of PCA treatment and

tensile strength -------------------------------------------------------------------------------101 Figure 4.29 Effect of carboxyl content and concentration on whiteness index of the

cationic chitosan (molecular weight of 1.4 x 105g/mole) treated fabrics-------------103 Figure 4.30 Effect of carboxyl content and concentration on whiteness index of the

cationic glycerin treated fabrics -----------------------------------------------------------103 Figure 4.31 Effect of carboxyl content and concentration on whiteness index of the

calcium chloride and magnesium chloride treated fabrics -----------------------------104 Figure 4.32 Effect of %Nitrogen fixed and concentration on whiteness index of the PCA

treated fabrics --------------------------------------------------------------------------------105

xii

Figure 4.33 Effect of %Nitrogen fixed and concentration on whiteness index of the BTCA treated fabrics --------------------------------------------------------------------------------106

Figure 4.34 Effect of treatment on whiteness index ------------------------------------------108 Figure 4.35 Effect of carboxyl content and concentration on stiffness of the cationic

chitosan (molecular weight of 1.4 x 105g/mole) treated fabrics -----------------------110 Figure 4.36 Effect of carboxyl content and concentration on stiffness of the cationic

glycerin treated fabrics----------------------------------------------------------------------110 Figure 4.37 Effect of carboxyl content and concentration on stiffness of the calcium

chloride and magnesium chloride treated fabrics----------------------------------------111 Figure 4.38 Effect of %Nitrogen fixed and concentration on stiffness of the PCA treated

fabrics -----------------------------------------------------------------------------------------112 Figure 4.39 Effect of %Nitrogen fixed and concentration on stiffness of the BTCA treated

fabrics -----------------------------------------------------------------------------------------113 Figure 4.40 Effect of treatment on stiffness----------------------------------------------------115

1

1. INTRODUCTION

The textile market has shown an interest in the demand for easy care, wrinkle-

resistant for cellulosic fabrics over the years. Untreated cellulose has poor recovery,

because cellulose is stabilized by hydrogen bonds within and between cellulose chains.

Moisture between the polymer chains can invade the cellulose structure and can

temporarily release the stabilizing hydrogen bonds and hydrogen bonds in cellulose

experience frequent breaking and reforming when extended and newly formed hydrogen

bonds tend to hold cellulose chain segments in new positions when external stress is

released. Preventing wrinkling of cellulosic fabric can be accomplished by the

crosslinking of polymer chains, thus making intermolecular bonds between chains that

water cannot release. In a typical durable-press (DP) treatment, some hydrogen bonds are

replaced with covalent bonds between the finishing agent and the fiber elements. Because

covalent bonds are much stronger than hydrogen bonds, they can resist higher external

stress. Hence, treated cellulose has a higher initial modulus and better elastic recovery.

After the external force is released, the energy stored in the strained covalent bonds

provides the driving force to return chain segments back to their original positions.

Formaldehyde-based cellulose crosslinking was a very important textile chemical

breakthrough of the 1930's, and is still the basis for a vast array of modern finished cotton

products today. N-methylol crosslinkers have the biggest use in durable press finishing.

They give fabrics crease resistance, shrinkage control, anti-curl, and durable press, but

2

they also impart strength loss and release formaldehyde, a known human carcinogen. [1]

Today’s textile industry has for a long time been searching for durable press finishes that

can give same results as formaldehyde based finishes, but cause less strength loss and no

formaldehyde release. For example, polycarboxylic acids and citric acid have been used

with varying degrees of success. [2, 3]

We have developed multiple methods of forming ionic crosslinks to give non-

wrinkle effects to cellulosic fabric. [4] These includes, (1) treatment of cellulose with an

anionic material and reacting with a polycation, (2) treatment of cellulose with a cationic

material and then application of a polyanion, (3) treatment of cellulose with a

precondensate of an ionic reactive material and a polyelectrolyte of the opposite charge.

The performance of crosslinkers can be measured by dry and wet wrinkle recovery angle

(WRA). Dry WRA is important for outerwear clothing to help resist dry wrinkling during

wearing, but wet WRA is more important for bedding which is almost never ironed and

must resist wrinkling during laundering. We observed simultaneous enhancements of both

wet and dry WRA as well as significant strength gain and excellent washing durability.

Polyelectrolytes are strongly bond and thus do not desorb during laundering. The

chemicals are common industrial reactants and do not have unusual safety or

environmental issues. Processes use existing equipment and no high temperature curing is

necessary. In addition, ionic crosslinks may have other important advantages, such as

antimicrobial activity and enhanced dyeability.

3

2. LITERATURE REVIEW

2.1 Cellulose chemistry

We can only understand chemical as well as physical properties of cellulose by the

knowledge of both chemical nature of the cellulose molecules and their structural and

morphological arrangement in the solid, mostly fibrous, state. For example reactivity of

the functional sites in the cellulose molecules and structural characteristics of polymers

such as; inter- and intramolecular interactions, and size of crystallites and fibrils. These

structural characteristics of the cellulosic polymers influence the physico-mechanical

properties utilized in the textile industry. The largest part of the cellulosic polymers used

for textile substrates comes from cotton.

Cotton is a soft fiber that grows around the seeds of the cotton plant. The fiber is

most often spun into thread and used to make a soft, breathable textile. Cotton is a

valuable crop because only about 10% of the raw weight is lost in processing. [5] Once

traces of wax, protein, etc. are removed, the remainder is a natural polymer of pure

cellulose. This cellulose is arranged in a way that gives cotton unique properties of

strength, durability, and absorbency. After scouring and bleaching, cotton is 99% pure

cellulose. [6] Cellulose is a macromolecule made up of anhydroglucose units united by 1,

4, oxygen bridges as shown in Figure 2.1. The anhydroglucose units are linked together as

beta-cellobiose; therefore, anhydro-beta-cellobiose is the repeating unit of the polymer

chain. The number of these repeat units that are linked together to form the cellulose

polymer is referred to as the degree of polymerization and is between 1000 and 15000. [7]

4

O

O

OH

HH

H

H H

OHOH

OH

OO

OH

HH

H

H H

OH

OH

O

O

OH

HH

H

H H

OH

OH

O

OHOH

HH

H

H

HOH

OH

nCellulose

Figure 2.1 Molecular structure of a cellulose polymer chain

The cellulose chains within the cotton fibers tend to be held in place by hydrogen

bonding. These hydrogen bonds occur between the hydroxyl groups of adjacent molecules

and are more prevalent between the parallel, closely packed molecules in the crystalline

areas of the fiber as shown in Figure 2.2. [8]

Figure 2.2 Crystalline and amorphous structure of cellulose

The chemical characters of the cellulose molecules are determined by the

sensitivity of the three-hydroxyl groups, one primary and two secondary, in each repeating

cellobiose unit of cellulose, which are chemically reactive groups. These groups can

undergo substitution reactions in procedures designed to modify the cellulose fibers such

5

as esterification and etherification or in the application of dyes and finishes for

crosslinking. The hydroxyl groups also serve as principal sorption sites for water

molecules. Directly sorbed water is firmly chemisorbed on the cellulosic hydroxyl groups

by hydrogen bonding. [8] Of particular interest in the case of cellulosic fibers is the

response of their strength to variations in moisture content. Generally, in the case of

regenerated and derivative cellulosic fibers, strength decreases with increasing moisture

content. In contrast, the strength of cotton generally increases with increased moisture.

The contrast seen between the fibers in their response to moisture is explained in terms of

intermolecular hydrogen bonding between cellulose chains and their degree of

crystallinity. [8]

2.2 Cellulosic fabric’s nature of wrinkling

The textile market has shown an interest in the demand for easy care, wrinkle-

resistant for cellulosic fabrics over the years. Improvements in crease angle recovery

property are obtained by chemical treatments, which improve the ability of fibers to

maintain configurations in which they are treated. [9] Untreated cellulose has poor

recovery, because hydrogen bonds in cellulose experience frequent breaking and

reforming when extended, and newly formed hydrogen bonds tend to hold cellulose chain

segments in new positions when external stress is released. In a typical durable-press

treatment, some hydrogen bonds are replaced with covalent bonds between the finishing

agent and the fiber elements. Because covalent bonds are much stronger than hydrogen

bonds, they can resist higher external stress. Hence, treated cellulose has a higher initial

6

modulus and better elastic recovery. After the external force is released, the energy stored

in the strained covalent bonds provides the driving force to return chain segments back to

their original positions. However, chemical treatment on cellulose also causes the loss of

mechanical properties. [10] The classical explanation to this problem is that traditional

crosslinks are too rigid to allow cellulose chain segments to move.

2.3 Durable Press finishing of cotton

Durable press is shaping a garment and then treating it in such a way that after

wearing and washing it will return to its pre-set shape. In order to produce non-wrinkle

cellulosic fabrics the durable press finishing has been developed.

The original process for the production of crease resistant fabrics was developed in 1928.

[11] DP finishes have been marketed ever since. Durable press is accomplished by resin

treatments. The main purpose of resin treatments is to overcome a serious drawback of

cellulosic fabrics, for example their ease of wrinkling, which requires ironing after

washing. [12] Ideally, a DP finished fabric will wash and dry to a completely smooth

state. The usual method of production of crease resistant fabric consists of padding fabric

trough a crosslinking agent along with a catalyst and other additives, drying at 100-110oC

followed by curing at 155-175oC for 2-3 minutes. [13] The resulting fabric has the ability

of recovering from creases both when fabric is wet and dry. The selection of crossslinking

agents for DP finishing is important. There are a large number of cross linker available.

Some of the most common reagents are urea-formaldehyde derivatives, melamine-

7

formaldehyde derivatives and methylol derivatives. All of these reagents used for DP of

cellulosic fabric with varying degrees of success.

2.3.1 Urea-Formaldehyde derivatives

The first widely used crosslinking agent for DP finishing was urea-formaldehyde

adducts. These products are mostly prepared at the finishing plant; also precondensate are

available in the market. The treatment of fabrics with urea-formaldehyde resin involves

padding the fabric through precondensate and an acid catalyst, drying, curing and

washing. The advantages of urea-formaldehyde resins are the low cost and high

efficiency. The disadvantages are poor stability of the agent, poor durability and imparting

chlorine retention to the fabric. The chlorine retention is due to the presence of the –NH

groups which react with chlorine from the bleach or laundry bath. [14, 15, 16] The

reaction of –NH groups and chlorine produces hydrochloric acid and it is a strong acid

that causes tendering and yellowing of cellulose.

2.3.2 Melamine-Formaldyhe derivatives

The most commonly used melamine product is trimethylol melamine. It has good

stability and durability. Trimethylol-melamine is more expensive than urea-formaldehyde.

It picks up and retains chlorine, it also yellows the bleached fabric but the fiber

degradation due to strong acid is avoided because of basicity of the compound. [17, 18]

8

2.3.3 Methylol derivatives of cyclic ureas

These compounds are also referred to as fiber reactants, because they only react

with the cellulose instead of themselves. As a result insoluble resin on the surface of the

fabric is absent hence the finished fabric have a softer hand. The members of this group

are:

(a) Dimethylol ethylene urea (DMEU) has high reaction efficiency and low price. [19] It

can produce high wrinkle recovery angles at low add-ons. The finish with DMEU is

sensitive to acids and can be destroyed by acid treatment during laundering. (b)

Dimethylol propylene urea (DMPU) is suitable for white goods, since it does not produce

yellowing on heating. [20] Another advantage of it is that not giving any odor. But the

finish is not susceptible to chlorine retention damage. It is more expensive than others in

the group. (c) Dimethylol dihydroxy ethylene urea (DMDHEU) as shown in Figure 2.3. It

is the most commonly used DP finish agent and gives excellent crease angle recovery.

[21, 22]

NN

O

OHOH

OHOH

DMDHEU

Figure 2.3 Molecular structure of DMDHEU

9

It shows some chlorine retention therefore it is not recommended for white goods. It does

not effect the lightness of the dyes hence it is dominating the colored garments durable

press finishing.

2.3.4 Effects of formaldehyde based DP finishes on cellulose

Formaldehyde-based N-methylol reagents are the most common DP reagents. But

these reagents produce losses in tensile strength of cotton due to depolymerization of

cellulose chains. Cellulose depolymerization occurs with a polycarboxylic acid or a Lewis

acid, which are catalysts for formaldehyde based resins. As a result they cause a high

degree of depolymerization. A direct correlation between tensile strength loss of the

treated cotton and the molecular weight of cellulose was found. [23] Severe tensile

strength loss is a major disadvantage of DP finished cotton fabrics, and it continues to be

the major obstacle for DP applications. Most of the studies of mechanical strength of

durable press finished cotton fabrics in the past have focused on changes in the gross

properties of cotton fabrics, such as tensile strength and abrasion resistance. Another

disadvantage of N-methylol reagents is later formaldehyde release. In recent years there

have been extensive efforts to find non-formaldehyde alternatives due to increasing

concern with health risks associated with formaldehyde. On the other hand, the final

textile products not only have to be eco-friendly, but also have to be produced by clean

technologies. Crosslinking of cellulose with N-methylol crosslinking agents to impart

wrinkle-resistance, shrink proofing, and smooth drying properties by virtue of chemical

reaction with cellulosic hydroxyl groups to form covalent crosslinks in the interior of

10

cellulosic fibers have successfully been done. However, at the present time, presence of

formaldehyde in the finished product, working atmosphere, as well as in wastewater

streams is considered as highly objectionable due to the mutagenic activity of various

aldehydes, including formaldehyde. [24]

2.4 Recent developments in non-formaldehyde DP applications

Extensive research has attempted to develop nonformaldehyde crosslinking agents

to replace N-methylol compounds that release formaldehyde during production and

storage, which is proven to be carcinogenic. [25] Durable press finishing, used to

overcome wrinkling problems in cotton fabric for some years, involves chemical

crosslinking agents that covalently crosslink with hydroxyl groups of adjacent cellulose

polymer chains within cotton fibers. This crosslinking not only results in the fabric's

wrinkle resistance, but also in discoloration and impairment of fabric strength and of other

mechanical properties. The early chemical agents used for crosslinking with cellulose

were mostly formaldehyde and formaldehyde derivatives, which can form ether bonds

with cellulose. DMDHEU is the most widely used crosslinking agent because it provides

good durable press properties at a lower cost and an acceptable level of detrimental effects

on fabric strength and whiteness compared to other N-methylol agents. However, fabric

treated with DMDHEU tends to release formaldehyde vapors during processing, storage,

and consumer use. Because formaldehyde is toxic to human beings, several attempts have

been made to replace it with formaldehyde-free crosslinking agents.

11

Several polycarboxylic acids have served as durable press agents. Carboxylic

groups in polycarboxylic acids are able to form ester bonds with hydroxyl groups in

cellulose. The main advantages of polycarboxylic acids are that they are formaldehyde-

free, do not have a bad odor, and produce a very soft fabric hand. BTCA (1.2,3,4-

butcnetetracarboxylic acid) is the most effective polycarboxylic acid for use as a durable

press agent as shown in Figure 2.4. In the presence of sodium hypophosphite monohydrate

as catalyst, BTCA provides almost the same level of durable press performance and finish

durability with laundering as the conventional DMDHEU reactant, but its high cost may

be an obstacle to a mill's decision to use it as a replacement for the conventional durable

press reactant. As with DMDHEU, fabrics treated with polycarboxylic acids generally

lose their strength, [26] probably due to excess crosslinking with cellulose chains. This

may be tackled by using long-chain polycarboxylic acids, which can be obtained through

copolymerization of two unsaturated polycarboxylic acids.

BTCA satisfies many desirable requirements such as durability to laundering and

durable press performance. Crosslinking of cellulose molecules with BTCA increases

fabric wrinkle resistance at the expense of mechanical strength. [27]

12

COOH

COOH

COOH

COOH

BTCA

Figure 2.4 Molecular structure of BTCA

Severe tensile strength loss diminishes the durability of finished cotton garments.

The factors involved in strength loss of cotton fabric treated with BTCA include acid

catalyzed degradation of cellulose molecules and their crosslinking. The common

catalysts for polycarboxylic acids are phosphorous-containing compounds, although their

use has disadvantages such as high cost, strength loss and raises some environmental

concerns. In order to decrease strength retention other catalysts have been proposed;

among these is boric acid, [28] which was added to increase strength of the treated fabrics.

With this treatment, durable press properties were similar to those obtained with sodium

hypophosphite; moreover the mechanical resistance improved.

A previous study [29] indicated that cellulosic fabric treated with a copolymer

made with maleic and acrylic acids possesses the same level of wrinkle resistance as with

BTCA, while tensile strength retention improves slightly. Another disadvantage of

polycarboxylic acid finishing is yellowing of the treated fabric. It is proposed that the use

of a copolymer between acrylic and maleic acids as a durable press finishing agent can

improve crease angle recovery for cotton fabric. [29] However, the copolymer treatment

does not provide as good tensile strength and whiteness as DMDHEU.

13

Chitosan citrate has been evaluated as non-formaldehyde durable press finish to

produce wrinkle-resistance and antimicrobial properties for cotton fabrics. [30] The

carboxylic groups in the chitosan citrate structure were used as active sites for its fixation

onto cotton fabrics. The fixation of the chitosan citrate on the cotton fabric was done by

the padding of chitosan citrate solution onto cotton fabrics followed by a dry - cure

process. The factors affecting the fixation processes were systematically studied. The

antimicrobial activity and the performance properties of the treated fabrics, including

tensile strength, wrinkle recovery, wash fastness and whiteness index, were evaluated. The

finished fabric shows adequate wrinkle resistance, sufficient whiteness, high tensile

strength and more reduction rate of bacteria as compared to untreated cotton fabric.

A non-polluting system of applying an easy-care finish to cotton fabrics has been

proposed. [31] The new formulation is based on an aqueous system of BTCA-chitosan-

sodium hypophosphite and was applied by the traditional pad-dry-cure method to an

Egyptian poplin. The variables studied were the concentrations of BTCA and chitosan, the

time and temperature of polymerisation. The study also included a comparison with other

traditional or recommended systems. The treated fabric was tested for crease recovery

angle, resistance to traction, elongation to breakage, rigidity, wetability, whiteness,

nitrogen content and dyeability. It was concluded that the new formulation gave

comparable if not better results than the traditional treatments.

14

2.5 Ionic crosslinking

Ionic crosslinking has been used in the polymer industry for various applications.

It is an alternative to covalent crosslinks. It is well known that the thermal resistance,

durability, abrasion resistance, chemical resistance, etc., of a polymer are improved by

crosslinking. For example, acrylic copolymer sizes have been used for improving the

weaving properties of polyester filament warps. [32] Acrylic sizes produce good abrasion

resistance, high strength, good adhesion and easy removability. But when exposed to high

humidity many of the acrylics absorb water and cause blocking on the beam. In order to

improve the stability of acrylic sizes divalent cations are used for reduction of the

moisture regain. Calcium and magnesium ions were used [32] for reducing the water

sensitivity of sizes. These cations form ionic crosslinks between the polymer chains and

stabilize the structure against moisture. Also these crosslinks improved the strength

properties of the polymer film.

The copolymer of propylene and maleic anhydride is also crosslinked by ionic

bonding. It is considered that the ionic crosslinking by maleic anhydride groups is

possible by using not only of magnesium hydroxide but also of other metal compounds.

Magnesium 12-hydroxy stearate, zinc oxide, and zinc sulfide were chosen for ionic

crosslinking. Accordingly, by changing the kind and content of the metal compounds, the

viscosity can be freely controlled. Considering also other rheological characteristics, these

ionically crosslinked compounds are assumed to show ideal flow processabilities except

for the extrudate appearance [33,34]

15

A series of siloxane-based liquid-crystalline elastomers were synthesized by using

ionic crosslinking agents containing sulfonic acid groups. The ions aggregated in domains

forces the siloxane chains to fold and form an irregular lamellar structure. Ionic

aggregates and liquid crystalline segments may be dispersed among each other to form

multiple blocks with increasing ionic crosslinking content. [35]

In a previous work [36] a vulcanized carboxylated nitrile rubber compound was

prepared using a mixed crosslinking system employing a mixture of zinc peroxide and

sulphur accelerators as vulcanizing agents to produce ionic and covalent structures.

Because of the existence of carboxyl groups in the polymeric chain, crosslinked polymers

of ionic nature can be obtained when a bivalent metal oxide, such as zinc oxide, is used as

a crosslinking agent. Ionic vulcanized compounds with properties equal to or better than

those produced using sulphur accelerators can also be obtained in the same way using

metal peroxides.

Polyurethanes are a versatile class of materials; their end applications dictate the

structure and morphology during synthesis. From the prepolymer stage through chain

extension and in the required cases of final crosslinking, there are many ways to influence

the final characteristics of the polyurethanes. Crosslinked networks are obtained through

ionic crosslinking and the different approaches produce cationic, anionic and Zwitter ionic

polyurethanes. These networks find a variety of applications as coatings, adhesives,

shoe soles, and vibration damping materials. [37]

16

2.6 Preparation of quaternized polymers

Conversion to quaternary ammonium salts gives products whose degree of

ionization is pH-independent. Such polymers can be prepared by reaction of polymers

with 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHTAC).

2.6.1 Chitosan and its reaction with CHTAC

Chitosan is the deacetylated form of chitin, poly [β-(1→4)-2-deoxy-D-

glucopyranose], is the second most abundant natural polymer next to cellulose. Chitosan

is a linear copolymer composed mainly β-(1→4)-2-amino-2-deoxy-D-glucopyranose and

partially β-(1→4)-2-acetamido-2-deoxy-D-glucopyranose residues. [38] Chitosan can be

dissolved in diluted acids by being protonated to soluble polyammonium salt. Hydroxyl

and amino groups of chitosan can react with epoxides by a ring opening reaction in either

present of a base or neutral conditions. These reactions were performed previously. [4, 39]

Kim at al performed the reaction between chitosan and CHTAC at neutral conditions.

They proved by FTIR and H1-NMR that the product they produced had a degree of

substitution larger than 60% and substitutions formed at NH2 sites. Because the hydroxyl

groups of chitosan are not sufficiently nucleophilic under neutral conditions, N-substituted

cationic chitosan can be obtained under neutral conditions.

On the other hand; in alkali conditions the hydroxyl groups of chitosan are

nucleophilic therefore reaction of chitosan and CHTAC produce O-substituted cationic

chitosan. Hasem at al performed the reaction under highly alkaline (pH=11-12) conditions

and they believe that the product was O-substituted cationic chitosan and soluble at

17

neutral conditions. Both of the products have cationic properties and can be used as a

cationic polyelectrolyte to form ionic crosslinks and anti-microbial finish for cellulosic

fabrics. [30, 40] Figure 2.5 shows the reaction of chitosan with CHTAC in alkaline

conditions.

O

O

NH2

HH

H

H H

OHOH

OH

OO

NH2

HH

H

H H

OH

OH

O

O

NH2

HH

H

H H

OH

OH

O

OHNH2

HH

H

H

HOH

OH

n

O

O

NH2

HH

H

H H

OHOH

O

OO

NH2

HH

H

H H

OH

O

O

O

NH2

HH

H

H H

OH

O

O

OHNH 2

HH

H

H

HOH

O N+

CH3

CH3

CH3O H

N+

CH3

CH 3

CH3O H

N+

CH 3

CH3

CH 3O H

N+

CH3

CH3CH3O H

n

Chitosan

N+

CH3

CH3

CH3

ClO H

N+

CH3

CH3

CH3O

Na OH

3-chloro- 2-hydroxypropyl trimethyl ammonium chloride Epoxypropyl trimethyl ammonium chloride

N+

CH3

CH3

CH3O

+

Cationic chitosan

Cl Cl

Cl

Cl Cl

Cl

Cl

(EPTAC)(CHTAC)

Figure 2.5 Reaction of chitosan with CHTAC in alkaline conditions

18

2.6.2 Reaction of Cellulose with CHTAC

The cationization of cellulose with using CHTAC has been previously studied.

[41,42,43] The process basicly takes place in two stages. From practical point this occurs

in a single process. Sodium hydroxide (NaOH) is the base catalyst. The cationic character

of cellulose is independent from pH. In the first stage the epoxide form of CHTAC formed

in the presence of NaOH. In the second stage this epoxide reacts with a hydroxyl group in

the cellulose.

The reaction efficiency for cationization of cellulose is low due to hydrolysis

reaction of CHTAC. Hydrolyzed CHTAC is no longer reactive therefore the efficiency is

less than perfect. There are many ways to perform the reaction for example, pad-batch,

pad-steam, exhaust, and pad-dry-cure methods. [42] All of these procedures give different

values of efficiency. The pad-batch process is consist of padding the fabric through a

mixture of NaOH and CHTAC solution at room temperature and followed by holding at

room temperature for 24 hours. The exhaustion procedure was studied at 75oC for 90

minutes. The mole ratio of NaOH and CHTAC varied. Also different solvent systems

were experimented such as; water, acetone, ethanol, isopropanol, and methanol. The

highest cationization level was obtained with acetone. The pad-steam application was

consist of padding the fabric through the mixture of CHTAC and NaOH and steaming at

100oC for 30 minutes. The pad-dry-cure method investigated at using different drying and

curing times and temperatures. The mole ratio of NaOH and CHTAC was also varied. The

best conditions for this application was after padding the fabrics drying at 35oC for 5

minutes followed by curing at 110oC for also 5 minutes. The exhaust method gave under

19

10% substitution, pad-batch and pad steam methods are more efficient, and they produced

about 25% substitution. The pad-dry-cure methods give fixations around 85%. The

efficiencies for all the methods decreased when increasing in concentration of CHTAC.

The optimum mole ratio was determined as 1.8 or greater. [42]

O

O

O H

HH

H

H H

OHOH

O H

OO

O H

HH

H

H H

OH

O H

O

O

O H

HH

H

H H

OH

O H

O

O HO H

HH

H

H

HOH

O H

n

O

O

O H

HH

H

H H

OHOH

O

OO

O H

HH

H

H H

OH

O

O

O

O H

HH

H

H H

OH

O

O

O HO H

HH

H

H

HOH

O N+

C H 3

C H 3

C H 3O H

N+

C H 3

C H 3C H 3O H

N+

C H 3

C H 3

C H 3O H

N+

C H 3

C H 3

C H 3O H

n

Cellulose

N+

C H 3

C H 3

C H 3O

+

Cationic cellulose

Cl

Cl Cl

Cl

Cl

N+

C H 3

C H 3

C H 3

C lO H

N+

C H 3

C H 3

C H 3O

N a O H

3 -chloro- 2 -hydroxypropyl trimethyl ammonium chloride Epoxypropyl trimethyl ammonium chloride

Cl Cl

(EPTAC)(CHTAC)

Figure 2.6 Reaction of cellulose with CHTAC in alkaline conditions

20

2.7 Carboxymethylation of cellulose

Carboxymethylcellulose (CMC) is a derivative of cellulose that can be formed by

its reaction with alkali and chloroacetic acid. The CMC structure is based on the β-(1→4)-

D-glucopyranose polymer of cellulose as shown in Figure 2.7. Different preparations may

have different degrees of substitution. [44] CMC molecules are somewhat shorter, on

average, than native cellulose with uneven derivatization giving areas of high and low

substitution. This substitution is mostly 6-O-linked, followed in order of importance by 2-

O, 2,6-di-O- then 3-O-, 3,6-di-O-, 2,3-di-O- lastly 2,3,6-tri-O-.linked. It appears that the

substitution process is a slightly cooperative (within residues) rather than random process

giving slightly higher than expected unsubstituted and trisubstituted areas.

O

O

OH

HH

H

H H

OHOH

O

OO

OH

HH

H

H H

OH

O

O

O

OH

HH

H

H H

OH

O

O

OHOH

HH

H

H

HOH

O

O

O

O

O

O

O

O

On

Figure 2.7 Molecular structure of carboxymethyl cellulose

CMC molecules are most extended (rod-like) at low concentrations but at higher

concentrations the molecules overlap and coil up. The average chain length and degree of

substitution are of great importance. At low pH, CMC may form cross-links through

carboxylic acid and free hydroxyl groups.

21

Cellulosic fabrics can react with several materials, which impart an anionic

character to it, for example, chloroacetic acid (CAA) and chlorosulfonic acid [4] and

sodium, 4-(4,6-dichloro-1,3,5-triazinylamino)-benzenesulfonate [45].

In a perivious study [4] carboxymethylation process was experimented first padding the

cellulosic fabric through sodium hydroxide solution, which opens the struchture of

cellulose, drying at a mild temperature and then padding through chloroacetic acid

solution and holding the fabric in a plastic bag at 70oC for 1 hour.

2.8 Proposed Research

Today’s textile industry has for a long time been searching for durable press finishes that

can give the same advantages as formaldehyde based finishes, but cause less strength loss

and no formaldehyde release.

We have developed multiple methods of forming ionic crosslinks to give non-

wrinkle effects to cellulosic fabric. These include, (1) treatment of cellulose with an

anionic material and reacting with a polycation, (2) treatment of cellulose with a cationic

material and then application of a polyanion, (3) treatment of cellulose with a

precondensate of an ionic reactive material and a polyelectrolyte of the opposite charge.

Methods 1 and 2, which we studied in this research, involve a pretreatment step for the

cellulosic fabric, but the third method is very similar to commercial DP applications. The

performance of crosslinkers can be measured by dry and wet wrinkle recovery angle

(WRA). Dry WRA is important for outerwear clothing to help resist dry wrinkling during

use, but wet WRA is more important for bedding which is almost never ironed and must

22

resist wrinkling during laundering. We observed simultaneous enhancements of both wet

and dry WRA. In addition, ionic crosslinks may have other important advantages, such as

antimicrobial activity and enhanced dyeability.

Cellulose can react with several materials, which impart an anionic character to it,

such as chloroacetic acid (CAA). On the other hand, cellulose can also react with cationic

materials that impart cationic character to it, for instance 3-chloro-2-hydroxypropyl

trimethyl ammonium chloride (CHTAC). Our work is based on Methods 1 and 2, the first

consisting of the reaction of cellulose with CAA, which producing partially

carboxymethylated cellulose, followed by a treatment with a polycation, such as,

cationized chitosan, cationized glycerine, cationized ethylene glycol, cationized dextrose

or cationized D-celobiose. We also observed WRA improvements with divalent cations

such as Ca++ and Mg++. Method 2 consists of the reaction of cellulose with CHTAC to

produce cationic cellulose, followed by the application of polyanion, such as,

polycarboxylic acids (PCA), 1,2,3,4-butanetetracarboxylic acid (BTCA),

ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid, trisodium salt, monohydrate

(NTA), ethylenediamine di(o-hydroxyphenylacetic acid (HEDTA), oxalic acid, citric acid,

or malic acid.

Both methods gave promising results with excellent washing durability.

Polyelectrolytes are strongly bond and thus do not desorb during washing. These

chemicals are common industrial reactants and there is also no unusual safety or

environmental issues. No high temperature curing is necessary. The processes utilize

existing equipment and similar processes are already widely used.

23

3. EXPERIMENTAL PROCEDURES

The materials, equipments and experimental procedures used in this study are

described in this section. The fabric is characterized, and the chemicals are identified their

manufacturers and chemical names. The equipment is described, and manufacturers are

named. Also the synthesis of experimental products and their application are presented.

The test procedures are listed, and detailed descriptions can be found in the appropriate

references.

3.1 Test Materials

The materials that used in this project are given in the table below including

names, brief descriptions and manufacturers.

Table 3.1 Test materials and chemicals Name or Group

Description Manufacturer

Cotton fabric Plain weave, style 400, 102 g/m2, 44”- 45”, 78 X 76, ISO 105/F02

Testfabrics Inc

Cationic agent

3-chloro-2-hydroxypropyl trimethyl (CHTAC) ammonium chloride, 69% solution

Dow Chemical

Oxidation agent

Sodium nitrate, 97.25%,m.p. 306°C, b.p. 380°C

Acros Organics

Base Sodium hydroxide, 50% aqueous solution Fisher Chemicals

Calcium chloride dehydrate, 77-80% CaCl2 Fisher Chemicals Salts Magnesium chloride hexahydrate, 99%

MgCl2 Fisher Chemicals

Ethylene glycol dimethyl ether 99+%, b.p. 84

oC -86oC Fisher Chemicals

Alcohols Glycerol, 99+%, b.p. 290°C Fisher Chemicals

24

Table 3.1 Test materials and chemicals continued CROSSLINK RB 105, Aqueous solution of polycarboxylic acids

BioLab Water Additives

CROSSLINK RB 120, 1,2,3,4-Butanetetracarboxylic acid

BioLab Water Additives

HEDTA, Ethylenediamine di(o-hydroxyphenylacetic) acid, trisodium salt

Lynx Chemical Group, LLC

NTA, Nitrilotriacetic acid, trisodium salt monohydrate, 92-94% aqueous solution

Hampshire Chemical Corporation

Polyanions

EDTA, Ethylenediaminetetraacetic acid, tetrasodium salt, 39% aqueous solution

BASF Corporation

Chitosan, medium viscosity with nominal degree of deacetylation of 91.5%

Vanson HaloSource, Inc.

Dextrose, D-(+)-Glucose, anhydrous Acros organics

Polysaccharides Cellobiose, D (+)-Cellobiose, 98% ,m.p.

239°C Acros Organics

Monochloro acetic acid, 99 + % Aldrich Chemical Company, Inc.

Oxalic acid anhydrous 98%, m.p. 189°C Acros Organics

DL-Malic acid 99%, m.p. 130°C to 132°C Acros Organics

Acids

Citric acid anhydrous 99%, m.p. 153°C to 154.5°C

Acros Organics

Ion exchange resin

Amberlite IRA-402 (Cl- form), 200g, 1.25 meq/mL, 4.1 meq/g

Fisher Chemicals

25

3.2 Equipments

Stirring was performed using a Fisher Hot Plate. A Fisher Scientific Co. model

600-pH meter was equipped with a standard combination pH electrode. Intrinsic viscosity

and viscosity average molecular weight determinations and cationization reactions were

performed in a water bath with an electrical temperature controller and a heavy-duty

stirrer. Application of finishes and ionic materials were performed using a 14-inch

Laboratory padding machine manufactured by Werner Mathis AG. Fabrics were dried and

cured, to their original dimensions on 7 X 12 inch metal pin frames, in a forced air oven

manufactured by Werner Mathis AG.

3.3 Application procedures

The ionic crosslinkers were applied to untreated and ionic cellulosic fabrics by

using three kinds of procedure. The procedures are given below.

3.3.1 Pad dry cure

Approximately 7 X 12 inch fabric samples were used. The fabrics dipped into the

various concentrations of aqueous polyelectrolyte solutions, followed by squeezing to a

wet pick up of approximately 100%. Then the wet fabric samples were pinned to the

original 7 X 12 inch dimensions, dried at 85oC for 5 minutes and cured at 140oC for 1.5

minutes. Finally the treated samples were washed using 2g/L nonionic wetting agent at

100oC for 10 minutes, rinsed with hot and cold water, centrifuged and dried at room

temperature for 24 hours.

26

3.3.2 Pad batch

The same size samples as in pad dry cure application were used. The fabrics were

padded through the ionic crosslinker solutions and squeezed to a wet pick up of

approximately 100%. Then the wet fabrics put into plastic bags, sealed and hold for 18

hours at room temperature. Followed by washing and drying the treated samples as

described above.

3.3.3 Exhaustion

The samples were put into 500mL glass beaker. Ionic crosslinker solution was

charged into the beaker. The bath ratio of fabric weight to weight of the bath was 1:15.

Then the beakers were located into a water bath and temperature raised to 95oC with a rate

of approximately 2oC/minutes and hold for 1 hour. The solution was stirred using an

electrical stirrer. Finally the samples were washed and dried as described previously.

3.4 Analysis and physical property tests

Including nitrogen, Fourier Transform Infrared Spectroscopy (FTIR), and Nuclear

Magnetic Resonance (NMR) were performed. Physical properties of untreated and treated

cellulosic fabrics including wrinkle recovery angles; tensile strength, stiffness and

whiteness index were also tested. The precise procedures are given below.

27

3.4.1 Nitrogen analysis

The nitrogen analysis was performed using a Leuco CHN analyzer. The analysis

performed using EDTA as standard and 3 independent samples approximately 0.1g each.

3.4.2 FT-IR analysis

FTIR analysis needs only a small sample size and it doesn’t take a long time

therefore it is one of the most useful techniques in polymer characterization. All IR

spectra in this work were obtained by using a Nicolet 510P FT-IR spectrophotometer. The

data collection parameters were 2.0 cm-1 resolution and 64 scans. The samples were

prepared as KBr pellets and were scanned against a blank KBr pellet backround. The

spectra contain absorbance on the y-axis and wavelength on the x-axis.

3.4.3 1H- NMR analysis

Nuclear Magnetic Resonance spectroscopy is a powerful technique for

determining the structure of simple inorganic to complex biochemical compounds. [46]

The usefulness of this technique in chemistry can be attributed to the very detailed

information obtained by NMR. For example in IR spectroscopy the spectroscopic features

are correlate with groups of atoms but in NMR spectroscopy the features correlates with

the individual atoms. Therefore much more detailed information can be obtained. The 1H-

NMR analysis was performed using GE NMR 300Ω (300 MHz) spectrometer at room

temperature and sodium 3-(trimethylsilyl) propane sulfonate was used as an internal

reference.

28

3.4.4 Wrinkle recovery angles

Wrinkle recovery angles were measured according to AATCC Standard Test

Method 66 option 2, Wrinkle Recovery of Fabrics: Recovery Angle Method. The wrinkle

recovery angles were recorded as the added total of warp and weft averages.

3.4.5 Tensile strength

The tensile strength of untreated and treated fabrics was determined with a

Syntech tensile strength tester according to ASTM Test Method D5035. Cellulosic fabrics

were tested only at warp direction and the breaking load (Lb) of the fabrics recorded.

3.4.6 Whiteness index

Using Spectraflush SF600X a double beam spectrophotometer, manufactured by

DataColor, CIE standard illuminant D65 and 1964 10o observer the CIE Whiteness Index

measurements of the cellulosic fabrics were performed according to AATCC test method

110, whiteness of textiles. Six measurements were obtained for each sample and average

value was calculated and recorded.

3.4.7 Stiffness

Stiffness measurements of fabrics were determined according to ASTM D 1388-96

Option A, Cantilever Test method. The bending length (cm) and the flexural rigidity (mg

X cm) of the fabrics were calculated and recorded. The fabrics were tested in the warp

direction.

29

3.5 Reaction of cellulose with chloroacetic acid

Cellulosic fabric was treated with anionic and cationic materials to produce ionic

cellulose. This approach gave us the opportunity of forming ionic crosslinks with using

both cationic and anionic polyelectrolytes.

The optimum conditions for carboxymethylation of cotton using CAA and

determination of carboxyl content were extracted from previous work. [4] Cotton fabric

samples were soaked in 20% NaOH aqueous solution for 10 minutes at room temperature

and squeezed to a wet pick up of approximately 100%. The samples were dried at 60oC

for 10 minutes. Then, the alkali treated samples were steeped in aquous solutions of

sodium salt of CAA with concentrations of 0, 0.5, 1, 1.5, and 2.5M, for 5 minutes and

squeezed to approximately 100% wet pick up. Sodium salt of CAA was prepared with

sodium carbonate. After the samples are packed in polyethylene bags and held at 70oC for

1 hour, they were washed several times with water (hot and cold), acidified with 0.2M

acetic acid and washed with distilled water to adjust pH of 7. Finally, they were dried at

RT for 24 hours.

Figure 3.1 shows the production of anionic cellulose in three steps. Note that the

crosslinks are bonded to cellulose through a very stable ether linkage.

30

O

O

OH

HH

H

H H

OHOH

OH

OO

OH

HH

H

H H

OH

OH

O

O

OH

HH

H

H H

OH

OH

O

OHOH

HH

H

H

HOH

OH

n

O

O

OH

HH

H

H H

OHOH

O

OO

OH

HH

H

H H

OH

O

O

O

OH

HH

H

H H

OH

O

O

OHOH

HH

H

H

HOH

O

O

O

O

O

O

O

O

On

Cellulose

ClO

O

Na

Na OH

Chloroacetic acid (Sodium salt)

+

Anionic cellulose

Figure 3.1 Reactions of cellulose with CAA that impart an anionic character

31

The carboxylic acid group content of the partially carboxymethylated cellulosic

fabrics were determined. [4] Cotton fabrics were cut into small pieces, 100mL of 0.5%

aqueous HCl solution prepared and fabric samples were steeped in it for 16 hours. The

samples were then filtered off and washed several times with distilled water until free

from HCl and having a pH of 7. Silver nitrate drop test was performed and it showed no

presence of chloride. The samples were dried at 105oC for 3 hours. Accurate weight of

samples (exactly 0.2g each) was soaked in 25mL of 0.05N aqueous NaOH solutions at

room temperature for 4 hours. First, a blank solution (solution without any sample) was

titrated with 0.05N aqueous HCl solution. Phenolphthalein pH indicator was used. The

volume of HCl solution (mL) spent was recorded for the blank. Then, each of the

solutions with different carboxymethylated samples was titrated in the same way as the

blank. The carboxyl contents of samples were calculated as follows:

mmols carboxymethyl content per 100 grams = 100 Χ (Vblank - Vsample)HCl Χ NHCl / 0.2

Where Vblank is the volume of HCl used for titration of blank solution, Vsample is the

volume of HCl used for titration of sample solution, and NHCl is the normality of

HCl titrant. Finally, we obtained five different carboxymethylation: 6.2, 30.2, 60.7, 87.1,

and 114.5 mmols of carboxymethyl groups per 100g of fabric, as determined by titration.

Table 3.2 shows the summary of the titration process.

32

Table 3.2 Results for carboxymethylation of cellulosic fabrics (Vblank=23.8ml)

Treatment CAA concentration

(M)

Sample no

Weight of sample

(g)

Vsample Carboxyl content

mmol/100g None

0 0 0.243 23.5 6.24

Carboxymethylation

0.5 1 0.258 22.25 30.21

Carboxymethylation

1 2 0.256 20.7 60.73

Carboxymethylation

1.5 3 0.253 19.45 87.12

Carboxymethylation

2.5 4 0.26 17.85 114.54

3.6 Reaction of Cellulose with CHTAC

Cationic cellulose was produced by cold pad batch treatment of fabrics with

mixtures of different mole ratios of CHTAC, cationization reagent, and NaOH. [42] We

used four different mol ratios, 0.46 /0.95, 1.28 /1.53, and 1.83 /2.2 respectively. Aqueous

solutions of each reactant were prepared separately as follows: A known amount of NaOH

was charged into a 1L beaker and filled with distilled water to 500mL and cooled to RT.

In the same way, a known amount from CHTAC solution was charged into another beaker

and filled with distilled water to 500mL. These two solutions were mixed in a 1000mL

beaker and cooled to RT in ice and immediately applied onto cotton as follows: fabrics

were padded through the CHTAC/NaOH solutions, squeezed to a wet pick up of

approximately 100% and rolled on to a beam. The fabrics were then covered with plastic

to stop air interaction and held overnight at RT. Finally, fabrics were

33

washed with a nonionic wetting agent at boiling temperature for 10 minutes, centrifuged

and dried at RT for 24 hours. Application with the last mole ratio (1.83/2.2) was repeated

multiple times in order to accomplish higher degrees of cationization.

The possible reaction mechanism is shown in Figure 3.2. Note that the crosslinks

are also bonded to cellulose through a very stable ether linkage. Percent nitrogen fixed

onto cellulosic fabric used for quantitatively characterization of cationic cellulose. The

level of nitrogen fixed for each treatment was determined by Nitrogen analysis. The

nitrogen levels of untreated and treated fabrics were as follows: 0.24%, 0.45%, 0.73%,

1.15% and 1.54% respectively.

34

O

O

OH

HH

H

H H

OHOH

OH

OO

OH

HH

H

H H

OH

OH

O

O

OH

HH

H

H H

OH

OH

O

OHOH

HH

H

H

HOH

OH

n

O

O

OH

HH

H

H H

OHOH

O

OO

OH

HH

H

H H

OH

O

O

O

OH

HH

H

H H

OH

O

O

OHOH

HH

H

H

HOH

O N+

CH3

CH3

CH3OH

N+

CH3

CH3CH3OH

N+

CH3

CH3

CH3OH

N+

CH3

CH3

CH3OH

n

Cellulose

N+

CH3

CH3

CH3O

+

Cationic cellulose

Cl

Cl Cl

Cl

Cl

N+

CH3

CH3

CH3

ClOH

N+

CH3

CH3

CH3O

Na OH

3-chloro-2-hydroxypropyl trimethyl ammonium chloride Epoxypropyl trimethyl ammonium chloride

Cl Cl

(EPTAC)(CHTAC)

Figure 3.2 Reactions of cellulose with CHTAC that impart a cationic character

35

3.7 Synthesis of compounds

All the compounds synthesized in this research are given below with detailed

procedures and characterization methods.

3.7.1 Molecular weight determination of chitosan

The viscosity average molecular weight (Mv) of chitosan can be determined by the

Mark Houwink equation, [47] where [ή] is intrinsic viscosity determined from a Huggins

plot and k and α are empirical coefficients dependent on the DD of chitosan.

[ή]=k Mvα

Wang and coworkers established the functional relationships for k and α as a function of

%DD of chitosan when chitosan is dissolved in 0.2M CH3COOH/0.1M CH3COONa

aqueous solution at 30oC.

k=1.64 * 10-30 * (%DD)14

α=-1.02 * 10-2 * (%DD) + 1.82

The Mv of chitosan was determined by the method of Wang et al. [47] A known amount

of thoroughly dried chitosan was dissolved in 0.2M CH3COOH/0.1M CH3COONa

aqueous solutions and a series of dilute solutions were prepared. A Cannon-Ubbelohde

semi- micro Viscometer (size 1, No. J536, Viscometer Constant=0.00745 mm2/s2 (cSt/s)

36

was charged with 3mL of each solution and equilibrated to 30oC in a water bath. Three

flow times were recorded at each concentration and averaged. Specific viscosity

(ήsp) were calculated according to the following equation,

ήsp= (t – ts)/ ts

Where t is a sample flow time and ts is a solvent flow time. The result of viscosity

measurements is reported in Table 3.3.

Table 3.3 Scheme of intrinsic viscosity measurement for the low viscosity chitosan. c (g/mL) Solvent 0.002499 0.001999 0.001499 0.000999 0.000499

time (sec) 89.75 320.56 265.19 211.99 161.8 122.47

ήsp 2.571699 1.954763 1.362006 0.802786 0.364568

ήsp/c 1029.091 977.8706 908.6095 803.5891 730.5977

The intrinsic viscosity [ή] was determined by the extrapolating the linear

regression of plots of ήsp/c versus c, where c is concentration of chitosan solution (g/mL),

to zero concentration as shown in Figure 3.3. The DD obtained from the manufacturer

certificate of analysis of the chitosans. Also DD was used to calculate k and α, which were

used together with [ή] to calculate Mv of chitosans using the Mark-Houwink equation.

Table 3.4 shows the properties of the chitosan.

37

Figure 3.3 Huggins plot of ήsp/c versus c for the cationic chitosan

Table 3.4 Properties of the Low Viscosity chitosan.

Chitosan %DD k α [ή] Mv

Low Viscosity

93.5 0.006400389 0.8663 658.73 6.11*105

3.7.2 Depolymerization of chitosan and characterization

The hydrolytic fragmentation of chitosan with HCl, and the oxidative

fragmentation with NaNO3 and H2O2

are the possible chemical methods. [48] HCl

fragmentation can be done at 65oC. Oxidative reactions take place at room temperature.

The number of chain scission depended on the concentration, time and temperature of the

chemical reagents. A previous work done by M. R. Kasaai showed that the rates of

y = 154254x + 658.73R2 = 0.9867

0

200

400

600

800

1000

1200

0 0.001 0.002 0.003

Concentration (g/mL)

intr

insi

c vi

s. /

conc

entr

atio

n

38

fragmentation with HCl and NaNO3 are higher than with H2O2. Also he examined the

chemical structure of chitosan and of its fragments by 1H-NMR spectroscopy. The

fragmentation process with H2O2 and NaNO3 did not alter the chemical structure and

degree of acetylation significantly. However, in acid hydrolysis, the degree of acetylation

decreased somewhat with fragmentation. The polydipersity of the fragments by the

chemical methods were similar and similar to the original one. Higher values of chain

scission were obtained with oxidative fragmentation with NaNO3 in shorter duration. The

initial rate of hydrolysis and oxidation with NaNO3were faster than the others. Also

oxidative degradation of chitosan with NaNO3 can be easily performed at room

temperature and desirable fragments can be achieved in relatively shorter durations.

Therefore we choose the oxidative degradation of chitosan with NaNO3.

The chitosan fragmentation is studied at 7.25 X 10-4M and 2.9 X 10-3M

concentrations of NaNO3 in a filtered initial chitosan solution (1% chitosan was dissolved

in 0.1M aqueous acetic acid solution). Reaction performed at room temperature with

constant stirring for various times. After the reaction, chitosan is recovered from the

reaction mixture as follows: The reaction mixture is neutralized with 1N NaOH to

precipitate the depolymerized chitosan. The chitosan is recovered by vacuum filtration

and remaining solid chitosan washed several times with distilled water to pH 7. Polymer is

collected in a drying bottle and dried at 70oC overnight in an air forced oven. Final drying

was done in a vacuum oven at 70oC for 24 hours.

A known amount from each recovered depolymerized chitosan was dissolved in

0.2M CH3COOH/0.1M CH3COONa aqueous solution at 30oC. The intrinsic viscosities

39

and the viscosity average molecular weight of depolymerized chitosan were determined

by the same method used to determine the molecular weight of original chitosan but with

different viscometer. The viscometer that was used is a Cannon Ubbelohde semi-micro

Viscometer (size 75, No. N177, Viscometer constant = 0.00745 mm2/s2 (cSt/s)). Table 3.5

summarizes the results of depolymerization of chitosan.

Table 3.5 Intrinsic viscosity and Mv of depolymerized chitosan

NaNO3

concentration (M)

Time (minutes) Intrinsic viscosity Viscosity average

molecular weight

350 310.52 2.5 X 105

460 221.4 1.7 X 105

7.25 X 10-4

695 184.21 1.4 X 105

465 70.678 4.6 X 104

690 56.055 3.5 X 104

2.9 X 10-3

1410 51.045 3.2 X 104

3.7.3 Reaction of chitosan with CHTAC

The optimum condition for quaternization of chitosan has been extracted from

[40]. Three different molecular weights of chitosan were cationized as follows: 41.75g of

original chitosan with a molecular weight of 611000g/mole were added into 300g CHTAC

in a 2L glass beaker (1:4 mole ratio) and stirred for 10 minutes. 60mL of NaOH (50%)

40

was added drop wise into slurry to adjust the pH of 10 to 11. 1L of deionized water was

added to create a reaction medium to produce a better contact between quat and chitosan

molecules. The slurry was constantly stirred at 60oC for 20 hours in a water bath. Then,

the temperature was raised to 95oC and stirring was resumed for another 4 hours. The

product was then cooled to room temperature, filtered, and pH adjusted to 7 with acetic

acid. Figure 3.4 shows the possible reaction between chitosan and quat molecules.

The resulting reaction mixture was recovered by drying; the product had a high

degree of cationization and was easily redissolved in water at RT. With the same

procedure chitosans with molecular weight of 1.4 x 105g/mole and 3.2 x 104g/mole were

also cationized.

The solid content of each reaction mixture was determined by drying a known amount of

product at 70oC for 48 hours in an air forced oven. The solid content of each product was

used to prepare the polyelectrolyte solutions prior to crosslinking process.

41

O

O

NH2

HH

H

H H

OHOH

OH

OO

NH2

HH

H

H H

OH

OH

O

O

NH2

HH

H

H H

OH

OH

O

OHNH2

HH

H

H

HOH

OH

n

O

O

NH2

HH

H

H H

OHOH

O

OO

NH2

HH

H

H H

OH

O

O

O

NH2

HH

H

H H

OH

O

O

OHNH2

HH

H

H

HOH

O N+

CH3

CH3

CH3OH

N+

CH3

CH3

CH3OH

N+

CH3

CH3

CH3OH

N+

CH3

CH3CH3OH

n

Chitosan

N+

CH3

CH3

CH3

ClOH

N+

CH3

CH3

CH3O

Na OH

3-chloro-2-hydroxypropyl trimethyl ammonium chloride Epoxypropyl trimethyl ammonium chloride

N+

CH3

CH3

CH3O

+

Cationic chitosan

Cl Cl

Cl

Cl Cl

Cl

Cl

(EPTAC)(CHTAC)

Figure 3.4 Reaction of chitosan with CHTAC

42

3.7.3.1 Characterization of cationic chitosan by conductometric titration method

The amount of substitution on chitosan was obtained. Reaction between chitosan

and quat was done under alkali conditions, therefore it was expected that the product

could have some OH- ions as counter ions of quaternary ammonium salts. The OH- ions

must be exchanged to Cl- ions for characterization of degree of substitution (DS) by

conductometric titration. For this procedure, an ion-exchange column was prepared. [49]

Ion-exchange resin (Amberlite IRA-402 (Cl- form), 200g, 1.25 meq/mL, 4.1 meq/g) was

stirred in 1L of 12%(with volume) NaOH solution for 16 hours, filtered over a glass filter

and thoroughly washed with distilled water until neutral. The resin was stirred in 1L of

3M HCl solution for 3 hours and washed with deionized water until pH of 7. This fresh

ion exchange resin was charged into a 500mL burette.

Using the dialysis method, a known amount of cationic chitosan sample was

purified and dried as follows: 10mL of cationic chitosan mixture was charged into a 20cm

of cellulose acetate membrane with a molecular weight separation of 6000-10000 and

stirred in 3L of deionized water for 72 hours, water was changed every 12 hours, followed

by precipitating the chitosan in 1L of acetone. Then a small amount of pure cationic

chitosan was dried at 70oC for 24 hours in a vacuum oven. The pure cationic chitosan was

then transferred into a glass beaker and dissolved in 200mL of deionized water. The

cationic chitosan solution was allowed to flow down through the column. It was collected

in a beaker, precipitated in 1L of acetone and dried in a vacuum oven at 70oC for 16

hours. The DS of cationic chitosan was obtained by titration of the halide (Cl-) with

aqueous silver nitrate (AgNO3) solution. [50] The process was as follows: 0.1344g from

43

the dried cationic chitosan was dissolved in 100mL of deionized water and

conductometrically titrated with 0.017N AgNO3 solution. Titration was conducted at a

constant temperature (23.5oC). The titration curve for cationic chitosan is shown in Figure

3.5.

360

400

440

480

520

0 4 8 12 16 20 24 28 32

Volume of silver nitrate (mL)

Con

duct

ivity

(uS/

cm)

Figure 3.5 Conductometric titration curve of cationic chitosan

The amount of silver nitrate used at the bending point (22.3mL) equals to the amount of

Cl- ions on the cationic chitosan derivative. 1mL of 0.017N AgNO3 is equal to 1mg NaCl,

therefore 0.1g of the cationic chitosan contains 3.81588 X 10-4 moles of Cl- ions. The

percentage degree of substitution was calculated by the equation below:

DS = 100 Χ (MW Χ NCl-) / m

44

Where MW is the molecular weight of each repeating unit of the cationic chitosan when

the DS is 1 (314.89 g/mol), NCl- is the number of moles of Cl- ions in the cationic chitosan

(2.6523 Χ 10-4), and m is the mass of cationic chitosan sample in grams (0.1344g). Finally

the DS of cationic chitosan was calculated as 89%.

3.7.3.2 Characterization of cationic chitosan by FTIR analysis

In order to characterize the products, we obtained Fourier Transform Infrared

Spectroscopy (FTIR) spectrums. For the IR measurements pure cationic chitosan samples

were prepared by using the dialysis method as described previously. The samples were

prepared as KBr pellets and scanned against a blank KBr pellet background. Deacetylated

chitosan shows medium to strong absorption peaks in the range of 1650 to 1580 cm-1. The

major IR functional group frequencies relevant to chitin and chitosan are shown in Table

3.6.

45

Table 3.6 Major IR functional group frequencies relevant to chitin and chitosan [46] Frequencies Intensity Functional group Assignment 3420-3250 s Alcohol –OH OH stretch (solid & liquid)

3460-3280 m Primary amine –NH2 NH stretch; broad band, may have

some structures

350-3050 vs Ammonium, NH4+ NH stretch; broad band

3200-3000 v br Amino acid –NH3 NH3+ antisym stretch

2990-2850 m-s Aliphatic alkyl CH antisym stretch

2830-2810 m Primary amine –NH2 CH stretch

2750-2350 m-s, br Amine hydrohalides -

NH3+

NH3+ stretch, several peaks

1680-1630 vs Secondary amide C=O Carbonyl stretch (Amide I)

1650-1580 m-s Primary amine –NH2 NH2 deformation

1610-1560 vs Carboxylic acid slat –COO- COO- antisym stretch

1565-1475 vs Secondary amide –NH- NH deformation (Amide II)

1440-1260 m-s, br Alcohol C-OH in plane bend

1430-1390 s Ammonium, NH4+ NH2 deformation ; sharp peak

1400-1310 s Carboxylic acid salts –

COO-

COO- sym stretch; broad band

1310-1250 m Trans amide linkage C-N stretch (Amide III)

1240-1070 s-vs Ether –C-O-C C-O-C stretch; antisym stretch

1200-1015 s-vs Alcohol –C-O-H C-O stretch

1150-1070 vs Aliphatic ethers C-O-C antisym stretch

1120-1030 s Primary aliphatic amine C-

NH2

C-N stretch

860-760 vs- br Primary aliphatic R-NH2 NH2 wag

680-620 s Alcohol –C-O-H C-O-H bend

s=strong; m=medium; w=weak; v=very; br=broad; sym;symmetric; antisym=antisymmetric

46

The peaks (1646 cm-1 and 1599 cm-1) shown in Figure 3.6 respond to C=O of secondary

amide and NH2 of primary amine groups. [46]

0.0

0.2

0.4

0.6

0.8

1.0

1.2

5001000150020002500300035004000Wavenumbers (cm-1)

Abs

orba

nce

1646 1599

Figure 3.6 FTIR spectrum of deacetylated chitosan

The cationic chitosan spectrum shows a new strong peak at 1479 cm-1 in Figure 3.7. It is

induced from the C-H bond of (2-hydroxyl-3-trimethylammonium) propyl group, which

was a product of CHTAC and chitosan reacting at highly alkaline conditions.

47

0.0

0.2

0.4

0.6

0.8

1.0

1.2

5001000150020002500300035004000

Wavenumbers (cm-1)

Abs

orba

nce 1479

Figure 3.7 FTIR spectrum of cationic chitosan

3.7.3.3 1H-NMR spectrums of deacetylated and cationized chitosan

The Figure 3.8 shows the 1H-NMR spectra of deacetylated chitosan. The H-1 peak

is appeared at 4.84ppm and the H-2 peak appeared at 3.05ppm. The remaining protons H-

3, 4, 5, and 6 appeared as a group peak between 4.05ppm and 3.55ppm. The spectra

showed a clear separation of peaks.

48

Figure 3.8 1H-NMR spectrum of deacetylated chitosan

49

In order to characterize the O-substitute chitosan the N-substituted chitosan was

used as reference, because the N-substituted chitosan has only quaternary ammonium salts

on the NH2 site of chitosan, which proven by Kim et. al. [39] The O-substituted chitosan

spectra, the bottom spectra in Figure 3.9, showed a strong peak at 3.21 ppm and the

spectra of N-substituted chitosan, the top spectra in Figure 3.9, also showed a similar peak

at 3.19 ppm. Both of these peaks come from the CH3 groups of the quaternary ammonium

salt. Unlike the chitosan spectra both of the cationized chitosan spectra didn’t show a clear

separation of peaks. We believe that it is due to introducing a complex ammonium salt

group into the chitosan’s structure. Therefore both spectra didn’t give us the opportunity

of calculating the degree of substitution by using the intensities of the peaks. It is clearly

seen from the peaks that the spectrum of N-substituted chitosan is different than O-

substituted chitosan.

The H-2 peak shown in the spectrum of N-substituted chitosan is assigned at 2.91 ppm

with an intensity of 2.43. The same peak on O-substituted spectra assigned at 2.89 ppm

with an intensity of 0.97. The decrease in intensity for H-2 peak was significant, which

indicated that the ammonium salt groups were attached more on the O-position than on

the N-position of the chitosan. Note that the H-2 peak didn’t disappear because there was

still some substitution on NH2 site of the chitosan. The peak “H-1” in the O-substituted

derivative decreased compared to that in the N-substituted cationic chitosan. The peak did

not disappear. This indicated that O-substituted chitosan contains some substitutions over

NH2 site.

50

Figure 3.9 1H-NMR spectrum of O-substituted (above) and N-substituted (below) cationic chitosan

51

3.7.4 Reaction of glycerin and ethylene glycol with CHTAC

Reaction of alcohols with quat can be performed at mild temperatures and using

high mole ratios. Glycerin was cationized using the following method: 1156g (4 moles)

from CHTAC was charged into a 2L beaker, 228mL of 50%NaOH solution was added

dropwise to adjust pH of the CHTAC 10 to 11 and 46.05g (0.5 moles) from glycerin was

added into highly alkaline CHTAC solution. Note that glycerin to CHTAC mole ratio was

1:8. The mixture was stirred 10 minutes at RT, transferred into a preheated water bath and

stirred at 60oC for 20 hours. A viscose and yellowish mixture was collected at the end.

The resulting reaction product was cooled off to room temperature, filtered, and pH

adjusted to 7 with acetic acid. The reaction of glycerin with CHTAC is shown in Figure

3.10.

With a similar procedure, ethylene glycol is also cationized. This time the mole

ratio was kept at 1:4. The following procedure was followed: 272g (1 mole) from CHTAC

was charged into a 500mL of beaker. 60mL of 50%NaOH solution was added dropwise in

order to raise the pH of the quat solution to 10-11 and followed by adding 15.51g (0.25

moles) from ethylene glycol into highly alkaline CHTAC solution. The reaction was

performed with the same method that described for glycerin.

52

Glycerin

N+

CH3

CH3

CH3

ClOH

N+

CH3

CH3

CH3O

Na OH

3-chloro-2-hydroxypropyl trimethyl ammonium chloride Epoxypropyl trimethyl ammonium chloride

N+

CH3

CH3

CH3O

+

Cationic Glycerin

Cl Cl

Cl

(EPTAC)(CHTAC)

OH

OH

OH

O

O

O

N+

CH3

CH3

CH3

OH

N+

CH3

CH3

OH

N+

CH3

CH3

OH

CH3CH3

Cl

Cl

Cl

Figure 3.10 Reaction of glycerin with CHTAC

53

3.7.5 Reaction of cellobiose and dextrose with CHTAC

The similarity of the molecular structure of cellobiose, dextrose and chitosan we

used the cationization method of chitosan for reaction of CHTAC with both cellobiose and

dextrose. The procedure was as follows: 50g (0.18 moles) from CHTAC solution was

charged into a 250mL beaker and pH adjusted to 10-11 with 10mL of NaOH solution and

followed by adding 15.5g (0.045 moles) from cellobiose into highly alkaline quat solution.

The mixture stirred for 10 minutes at room temperature and transferred into a preheated

water bath. The mixture stirred at 60oC for 20 hours. Then the temperature raised to 95oC

and stirring continued for another 4 hours. Finally the reaction mixture was cooled off to

room temperature and pH adjusted to 7 with acetic acid.

With the same procedure dextrose was also cationized. For this procedure 90g

(0.32 mole) from CHTAC solution was charged into a 250 mL beaker and pH adjusted to

10-11 with 90mL of NaOH. Followed by adding 15g (0.08 mole) from dextrose into the

quat solution. The reaction performed using the same method described for cellobiose.

3.8 Preparation of fabric samples

For each crosslinker solution 5 samples, 1 untreated fabric sample and 4 ionic

cellulosic fabrics having different levels of ionic content, were prepared for treatment. The

samples were marked for determination of warp and weft directions of the fabric,

identification of the level of ionic content of the samples and concentration of crosslinker

solution that used to treat each sample. The sample size kept constant for all treatments

and was 7 X 12 inch.

54

3.9 Crosslinking of carboxymethylated cellulosic fabric

Untreated fabric having a carboxymethyl content of 6.2mmol/100g and

carboxymethylated cellulosic fabrics with anionic contents of 30.2, 60.7, 87.1, and

114.5mmole/100g, were treated with cationized chitosan, cationized glycerine, calcium

chloride, magnesium chloride, cationized ethylene glycol, cationized dextrose and

cationized D-cellobiose. All of these treatments are given below.

3.9.1 Treatment with cationic chitosan

Crosslinking with cationic chitosan was studied using pad-dry-cure, cold pad-

batch and exhaustion procedures. Fabrics with five different anionic levels were used. The

procedure was same for different molecular weight of cationized chitosans. For pad dry

cure and pad batch application 400mL of blank (0%) and three different concentrations of

polyelectrolyte, 1, 3, and 6 % with weight, solutions were prepared. Cationic chitosan

dissolved in deionized water at pH of 7. For exhaustion method 400mL of 6% with weight

cationic chitosan solution and 1:15 bath ratio was used.

3.9.2 Treatment with cationic glycerin

Crosslinking with cationic glycerine was studied using pad-dry-cure and

exhaustion methods. Fabrics with five different anionic levels were used. For this method

400mL of blank (0%) and three different concentrations of crosslinker, 1, 3, and 6 % with

weight, solutions were prepared. Cationic glycerine was also dissolved in deionized water

at pH of 7. For exhaustion method 12% with weight, of 400g solution was used. The

55

temperature rose to 95oC with a 2oC/minute grade and hold for 90 minutes and followed

by hot and cold washing of the samples and drying at room temperature for 24 hours.

3.9.3 Treatment with cationic cellobiose, cationic dextrose and cationic ethylene glycol

These treatments were studied as a prescreening study in order to identify if the

polyelectrolytes can impart crease angle recovery to anionic cellulosic fabric. Treatments

with cationic cellobiose, cationic dextrose, and cationic ethylene glycol were studied using

anionic cellulosic fabrics with two different carboxyl content, 30.2 and 60.7mmole/100g.

The concentrations of cationic crosslinkers were 6% with weight of the bath. All

treatments were applied using the pad dry cure procedure and followed by washing and

drying as described previously.

3.9.4 Treatment with calcium chloride and magnesium chloride

Calcium and magnesium are divalent atoms and they can be used as cationic

crosslinker agents. Treatments of calcium chloride and magnesium chloride performed

using pad dry cure procedure. The solutions were prepared as follows: 29.5g (0.2 mole)

from calcium chloride dihydride dissolved in 400mL of deionized water. It yielded to

0.5M of aqueous CaCl2 solution. With the similar way 0.5M magnesium chloride

hexahydrate solution was prepared by dissolving 40.6g from magnesium chloride in

400mL of deionized water. Fabrics with five different anionic levels were used. The pad

dry cure application method was applied and followed by washing and drying as described

above. Figure 3.11 shows the reaction of calcium with anionic cellulose.

56

O

O

OHH

H

H

H

H

OHOH

O

O

O

OHH

H

H

H

H

OH

O

O

O

OHH

H

H

H

H

OH

O

O

OH

OHH

H

HH

H

OH

O

O

O

O

O

O

O

O

O

Ca

O

O

OHH

H

H

H

H

OHOH

O

O

O

OHH

H

H

H

H

OH

O

O

O

OHH

H

H

H

H

OH

O

O

OH

OHH

H

HH

H

OH

O

O

O

O

O

O

O

O

O

Ca++

++

Anionic cellulose chain Anionic cellulose chain

Divalent calcium ion

Divalent calcium ion

Figure 3.11 Crosslinked anionic cellulose with calcium

57

3.10 Crosslinking of cationic cellulosic fabric

Various polyelectrolytes were used. Polyanion types were PCA, BTCA, EDTA,

NTA, HEDTA, oxalic acid, citric acid, and malic acid. The approach was to form ionic

crosslinks between cationic cellulose chains by reacting them with a polyanion. All of

these crosslinkers improved crease angle recovery of cotton with varying degrees of

success, but we accomplished higher WRA with PCA and BTCA treatments.

3.10.1 Treatment with PCA and BTCA

Untreated and cationized cotton fabrics with varying levels (0, 0.19, 0.28, 0.46,

and 0.57) of percent fixed nitrogen were used. Aqueous solutions of PCA and BTCA with

concentrations of 1, 3, and 6% with weight of the solution were prepared. The pH of the

solutions were adjusted to 6-7 with 50% NaOH solution, as the pH of both crosslinker

solutions were initially under 2, which may reduce the strength of cellulose. The

application procedure for treatments was pad dry cure method. After the treatments,

fabrics were washed and dried as described previously. The crosslinked cationic cellulose

with BTCA is shown in Figure 3.12.

58

O

O

OHH

H

H

H

H

OHOH

O

O

O

OHH

H

H

H

H

OH

O

O

O

OHH

H

H

H

H

OH

O

O

OH

OHH

H

HH

H

OH

O

N+

CH3CH3

CH3

OH

NCH3CH3

CH3

OH

N+

CH3CH3

CH3

OH

NCH3

CH3

CH3

OHO

O

OHH

H

H

H

H

OHOH

O

O

O

OHH

H

H

H

H

OH

O

O

O

OHH

H

H

H

H

OH

O

O

OH

OHH

H

HH

H

OH

O

N+

CH3CH3

CH3

OH

NCH3 CH3

CH3

OH

N+

CH3CH3

CH3

OH

NCH3

CH3

CH3

OH

COO

COO

COO

COO

Cl

Cl

Cl

Cl

- -

--

+ +

+ +

Cationic cellulose chain Cationic cellulose chain

BTCA

Figure 3.12 Crosslinked cationic cellulose with BTCA

59

3.10.2 Treatment with EDTA, NTA and HEDTA

Treatments were studied using five different %N fixed fabrics and three different

concentrations, 1%, 3%, and 6% with weight of the solution, of HEDTA, NTA, and

EDTA solutions. The pH of the solutions was adjusted to 7 with acetic acid. The pad dry

cure application procedure was used. The treated fabrics were washed and dried as

described above.

3.10.3 Treatment with oxalic acid, citric acid and malic acid

These treatments were performed as a prescreening study in order to identify if the

polyelectrolytes can impart crease angle recovery to anionic cellulosic fabric. Treatments

were studied using 2 different %N fixed fabrics (0.46 and 0.57) and 0.5M of crosslinker

solutions. The solutions were prepared as follows: 9g (0.1 mole) oxalic acid dissolved in

200mL of deionized water, 13.4g (0.1 mole) malic acid dissolved in 200mL of deionized

water and 19.2g (0.1 mole) citric acid dissolved in 200mL of deionized water. The pad dry

cure procedure was used. The treated fabrics were washed and dried as described above.

60

4. RESULTS & OBSERVATIONS AND DISCUSSION

In this section the results of the physical property measurements of the untreated

and treated fabrics are represented using figures. A detailed discussion for each property is

also stated.

4.1 Wrinkle recovery angles of conventional durable press finished fabrics

In order to compare the wrinkle recovery angles of ionic crosslinked fabrics the

crease angle recovery test was performed on the DMDHEU treated cellulosic fabric. The

dry/wet wrinkle recovery angles were 276/266 degrees respectively.

4.2 Wrinkle recovery angles of polycation treated anionic cellulosic fabrics

Wrinkle recovery angle data are presented for polycation treated anionic fabrics.

Carboxyl content on the cellulosic fabrics is given on the x-axis while dry/wet wrinkle

recovery angles are given on the y-axis.

4.2.1 Wrinkle recovery angles of cationic chitosan treated fabrics

The wrinkle recovery angles of untreated, carboxymethylated and cationic

chitosan treated samples are given in Tables A.1, A2 and A3 of the Appendix. The result

of DMDHEU treated fabric is also included in the tables. Standard deviation of crease

angle recovery measurements was between 3o and 12o for cationic chitosan treated fabrics.

As an example, the crease angle recovery measurements of 1.4 x 105g/mole cationic

61

chitosan treated fabrics are presented here. The relationship between carboxyl content of

the fabric, cationic chitosan concentration and dry/wet wrinkle recovery angles is shown

in Figure 4.1 and 4.2. The cationic chitosan is symbolized by CC. A correlation between

wet wrinkle recovery angles and carboxyl content of the fabrics for the treatments was

observed. Increase in carboxyl content increased the wrinkle recovery angles of treated

fabrics because high numbers of carboxylic groups on the cellulose form more ionic

crosslinks with cationic sites of the quaternized chitosan, therefore a higher crease angle

recovery was obtained. Both wet and dry wrinkle recovery angles were enhanced with an

increase in carboxyl content of the fabric treated. The effect of the cationic chitosan

concentration is not significant. On average the 3% crosslinker concentration seems to be

the most effective concentration. The treatments show wet wrinkle recovery angles

between 240 and 280o and dry wrinkle recovery angles between 180o and 230o. The

difference of wet crease angle recovery between blank samples and treated fabrics was up

to 120o, a very significant increase and up to 70o for dry wrinkle recovery angles.

62

120

160

200

240

0 30 60 90 120

Carboxyl content (mmol/100g)

Dry

wrin

kle

reco

very

ang

les

(deg

rees

) 0%1%CC3%CC6%CC

Figure 4.1 Effect of carboxyl content and concentration on dry wrinkle recovery angles of

cationic chitosan treated fabrics

120

160

200

240

280

0 30 60 90 120

Carboxyl content (mmol/100g)

Wet

wrin

kle

reco

very

ang

les

(deg

rees

) 0%1%CC3%CC6%CC

Figure 4.2 Effect of carboxyl content and concentration on wet wrinkle recovery angles of

cationic chitosan treated fabrics

63

The cationic crosslinker contains nitrogen, thus the nitrogen content of the treated

fabrics is proportional with the number of ionic crosslinks formed between the anionic

cellulose chains. The cationic chitosan treated fabrics are analyzed for % nitrogen

content. The results of three molecular weights of chitosan treatments are given in Table

A.36, A.37 and A.37 of the Appendix. The data of the fabrics treated with the molecular

weight of 1.4 x 105g/mole cationic chitosan is shown in Figure 4.3. The cationic chitosan

is symbolized by CC. The relationship between cationic chitosan concentration, carboxyl

content of the fabrics and % nitrogen fixed after treatment is presented here. The untreated

fabric was contained approximately 0.24% nitrogen, as the cotton fabric naturally contains

some impurities such as protein matter, pectin, minerals, and waxes. The fabric was

scoured and bleached, but it has been known that there is still some impurity residue on

the fabric. The carboxymethylation process did not significantly affect the nitrogen

content of the fabric. Anionic fabrics contained approximately 0.25% nitrogen. Anionic

fabrics treated with cationic polyelectrolyte showed a presence of various degrees of %

nitrogen fixation. The % nitrogen contents of the treated fabrics are changed by carboxyl

content of the fabrics and the crosslinker concentration. Fabrics with higher carboxyl

contents contain higher levels of nitrogen. The difference is more significant for fabrics

having 87.1mol/100g and 114.5mmol/100g carboxyl groups. The treatment with 6%

polyelectrolyrte concentration produced greater nitrogen fixation than the 3% cationic

chitosan treatment for high carboxyl levels. The 3% treatment showed slightly higher

nitrogen content for 30.2 mmol/100g carboxyl level than the 6% treatment, yet it is in the

expected standard deviation range. The 3% cationic chitosan treatment also produced

64

higher nitrogen fixation than the 1% treatment. The maximum nitrogen fixation was

0.54% and was obtained with the application of 6% cationic chitosan on the fabric

containing 114.5 mmol/100g carboxyl content.

0.20

0.30

0.40

0.50

0.60

0 30 60 90 120

Carboxyl content (mmol/100g)

%N

itrog

en c

onte

nt

0%1%CC3%CC6%CC

Figure 4.3 Effect of carboxyl content and concentration on %Nitrogen content of cationic chitosan treated fabrics

The wrinkle recovery angles of treated fabrics versus their nitrogen contents are

also plotted. Figure 4.4 shows the relationship between nitrogen level of the fabrics and

dry/wet wrinkle recovery angles. Wrinkle recovery angle is symbolized by WRA. The

data obtained with carboxymethylated fabrics are presented here. A correlation between

wet wrinkle recovery angles and % nitrogen content was observed. The correlation was

obtained with the coefficient of determination (R2) of 0.73 for wet wrinkle recovery

65

angles. The dry wrinkle recovery angle data of the treated fabrics did not show a good

correlation with the % nitrogen content, as most of the ionic crosslinks were formed while

the fabric was wet. Increases in % nitrogen content led to increases in wet crease angle

recovery for treated fabrics. As previously mentioned, the nitrogen content of the fabrics

is proportional with the number of the ionic crosslinks, therefore fabrics having greater

nitrogen contents are expected to produce higher wrinkle recovery angles than others. The

data obtained with cationic chitosan treatments indicated that fabrics with greater nitrogen

contents also produced higher crease angle recovery.

R2 = 0.7391

180

200

220

240

260

280

0.2 0.3 0.4 0.5 0.6

%Nitrogen content

Wrin

kle

reco

very

ang

les

(deg

rees

)

Wet WRADry WRA

Figure 4.4 The relationship between %Nitrogen content of the fabrics and dry/wet wrinkle

recovery angles

66

Several laundry washings were applied to the cationic chitosan treated fabrics

using a commercial detergent, Tide, and % nitrogen content of the fabric were tested. The

% nitrogen content was initially 0.67%, after one laundry washing it was 0.68% and was

0.59% after five laundry washings and 0.40% after ten laundry washings.

The anionic cellulosic fabrics were treated with three different molecular weights

of cationic chitosan. Regardless of molecular weight of the polycation, significant

increases in both dry and wet wrinkle recovery angles were observed, but the results show

that wet wrinkle recovery angles are higher than dry wrinkle recovery angles. The effects

of different molecular weights of cationic chitosan and carboxyl content of the fabrics on

wrinkle recovery angles are compared in Figures 4.5 and 4.6. These figures are produced

from the data obtained with 6% cationic chitosan concentration.

The change in molecular weight of cationic chitosan did not make a significant difference

on wrinkle recovery angles of the treated fabrics. Yet the results show that the lowest

molecular weight (3.2 x 104g/mole) cationic chitosan gave better results for dry wrinkle

recovery angles than other treatments.

67

160

200

240

0 30 60 90 120

Carboxyl content (mmol/100g)

Dry

wrin

kle

reco

very

ang

les

(deg

rees

) 611000g/mol140000g/mol32000g/mol

Figure 4.5 Effect of molecular weight of chitosan and concentration on dry wrinkle

recovery angles of cationic chitosan treated fabrics

150

200

250

0 30 60 90 120

Carboxyl content (mmol/100g)

Wet

wrin

kle

reco

very

ang

les

(deg

rees

) 611000g/mol140000g/mol32000g/mol

Figure 4.6 Effect of molecular weight of chitosan and concentration on wet wrinkle

recovery angles of cationic chitosan treated fabrics

68

Cationic chitosan was also applied on three levels of anionic fabrics using the exhaustion

method. The data is given in Table A.4 of the Appendix. The results show reasonably high

wet crease angle recovery, but dry wrinkle recovery angles are very low. The wet wrinkle

recovery angles are between 191o and 232o while the dry angles are between 120o and

135o. The fabric having 30.2mmole/100g carboxyl content treated by cold pad batch

method also showed a similar result. The wet wrinkle recovery angle measured as 248o

while the dry was only 147o. These results indicated that a curing step is needed in order

to obtain both high wet and dry wrinkle recovery angles.

4.2.2 Application of paired t-test analysis on cationic chitosan treatments

Given two paired sets of n measured values, the paired t-test determines whether

they differ from each other in a significant way under the assumptions that the paired

differences are independent and identically normally distributed. [51]

Paired t-test was applied to the cationic chitosan treatments using the statistics software,

StatCrunch.

This statistic has “n-1” degrees of freedom (DF: the number of degrees of freedom

in a problem, distribution, etc., is the number of parameters which may be independently

varied). If we define µ as the mean of the differences in wrinkle recovery angles between

two different molecular weights of cationic chitosan treated fabrics and then we set our

hypothesis (Ho) as “µ=0”, which implies that the difference in wrinkle recovery angles is

not significant. We can reject or accept the Ho using the results of the paired t-test.

69

If; Lower Limit< µ <Upper Limit, and then we “do not reject Ho”. For all other cases we

“reject Ho”, which means that the difference is significant.

Table 4.1 shows the paired t-test results of the dry wrinkle recovery angles of different

molecular weights of cationic chitosan treatments for 95% Confidence Interval (CI). The

calculated µ values of cationic chitosan treatments are contained in the 95% Confidence

Interval. Therefore we are 95% confident with accepting Ho, thus stating that the

differences are not significant.

Table 4.1 Paired t-test results for dry wrinkle recovery angles of cationic chitosan treated fabrics

95% CI Difference Mean of

Sample Difference (µ)

Standard Error of means

DF

Lower

Limit

Upper

Limit

6.11 x 105g/mol – 1.4 x 105g/mol

not significantly different 6.3333335 2.61254 14 0.7299794 11.9366

6.11 x 105g/mol – 3.2 x 104g/mol

not significantly different -6.266667 3.24619 14 -13.22906 0.69572

1.4 x 105g/mol – 3.2 x 104g/mol

not significantly different -12.6 2.69355 14 -18.3771 -6.8228

70

Table 4.2 shows the paired t-test results of wet wrinkle recovery angles of different

molecular weights of cationic chitosan treatments for 95% CI. The calculated µ values of

cationic chitosan treatments are contained in the 95% Confidence Interval. Therefore we

are 95% confident with accepting Ho, therefore stating that the differences are also not

significant.

Table 4.2 Paired t-test results for wet wrinkle recovery angles of cationic chitosan treated fabrics

95% CI

Difference Mean of

Sample Difference (µ)

Standard Error of means DF Lower

Limit

Upper

Limit

6.11 x 105g/mol – 1.4 x 105g/mol

not significantly different 0.0666666 3.57433 14 -7.59952 7.73285

6.11 x 105g/mol – 3.2 x 104g/mol

not significantly different 0.1333333 2.89805 14 -6.082379 6.34904

1.4 x 105g/mol – 3.2 x 104g/mol

not significantly different 0.0666666 2.89411 14 -6.140582 6.27391

71

4.2.3 Wrinkle recovery angles of cationic glycerin treatments

The wrinkle recovery angles of resin treated, untreated, carboxymethylated and

cationic glycerin treated samples are shown in Table A.5 of the Appendix. Standard

deviation of wrinkle recovery angle measurements in warp direction was 9 degree while it

was 4 degree in weft direction. The effect of carboxyl content and cationic glycerin

concentration on dry and wet wrinkle recovery angles are presented in Figure 4.5 and 4.6.

Cationic glycerin symbolized by CG. A correlation between wet wrinkle recovery angles

and carboxyl content of the fabrics was also observed. It is believed to be the increase in

the amount of crosslinks between the cellulose chains while increase in the

carboxymethylation level of the fabrics. The wet and dry wrinkle recovery angles were

enhanced with an increase in carboxyl content of the fabric treated. Wet wrinkle recovery

angles were higher than dry wrinkle recovery angles. Treatment of anionic cotton with

cationic glycerin showed wet wrinkle recovery angles between 240 and 280o and dry

wrinkle recovery angles between 180 and 230o. The average difference of wet wrinkle

recovery angles between blanks (0% polycation) and treated fabrics was 120o while it was

55o for dry crease angle recovery.

The cationic glycerin was also applied to the fabrics by exhaustion method. The results are

shown in Table A.6 in the appendix. The data also showed a better wet crease angle

recovery than dry. The wet wrinkle recovery angles are between 180 and 229o, the dry

wrinkle recovery angles are between 131 and 206o. These results imply that pad dry cure

application improves the durable press properties of cellulosic fabrics better than

exhaustion method.

72

120

160

200

240

0 30 60 90 120

Carboxyl content (mmol/100g)

Dry

wrin

kle

reco

very

ang

les

(deg

rees

) 0%1%CG3%CG6%CG

Figure 4.7 Effect of carboxyl content and concentration on dry wrinkle recovery angles of

cationic glycerin treated fabrics

120

160

200

240

280

0 30 60 90 120

Carboxyl content (mmol/100g)

Wet

wrin

kle

reco

very

ang

les

(deg

rees

)

0%1%CG3%CG6%CG

Figure 4.8 Effect of carboxyl content and concentration on wet wrinkle recovery angles of

cationic glycerin treated fabrics

73

The cationic glycerin treated fabrics were also analyzed for % nitrogen content.

The results of three molecular weights of the treatment are given in Table A.39 of the

Appendix. The relationship between cationic glycerin concentration, carboxyl content of

the fabrics and % nitrogen fixed after treatment is presented in Figure 4.9. The cationic

glycerin is symbolized by CG. The % nitrogen contents of the treated fabrics are also

affected by carboxyl content of the fabrics and the crosslinker concentration. Fabrics with

higher carboxyl contents contain higher levels of nitrogen. The difference is more

significant for fabrics having higher carboxyl contents. The treatment with 6% and 3%

polyelectrolyte concentrations produced greater nitrogen fixation than the 1% treatment,

but the difference between 3% and 6% varied as the carboxyl content of the fabrics were

changed. The maximum nitrogen fixation was 0.44% and it was obtained with application

of 3% cationic glycerin on the fabric containing 114.5 mmol/100g carboxyl content.

74

0.20

0.30

0.40

0.50

0 30 60 90 120

Carboxyl content (mmol/100g)

%N

itrog

en c

onte

nt

0%1%CG3%CG6%CG

Figure 4.9 Effect of carboxyl content and concentration on %Nitrogen content of cationic

glycerin treated fabrics

The wrinkle recovery angles of cationic glycerin treated fabrics and their nitrogen

contents are shown in Figure 4.10. The relationship between nitrogen level of the fabrics

and dry/wet wrinkle recovery angles of carboxymethylated and cationic glycerin treated

fabrics are presented here. Correlations between wet wrinkle recovery angles (WRA) and

% nitrogen content were determined. The correlations were obtained with the coefficients

of determination (R2) of 0.48 for wet wrinkle recovery angles (WRA) and 0.51 for dry

WRA. Increases in % nitrogen content showed increases in dry/wet crease angle recovery

for treated fabrics. As previously mentioned, the nitrogen content of the fabrics is

proportional with the number of the ionic crosslinks, therefore fabrics having greater

nitrogen contents are expected to produce higher wrinkle recovery angles than others. The

75

data obtained with cationic glycerin treatment also indicated that fabrics with greater

nitrogen contents also produced greater crease angle recovery than the others.

R2 = 0.4888

R2 = 0.5187

180

200

220

240

260

280

0.2 0.3 0.4 0.5

%Nitrogen content

Wrin

kle

reco

very

ang

les

(deg

rees

)

Wet WRADry WRA

Figure 4.10 The relationship between %Nitrogen content of the fabrics and dry/wet

wrinkle recovery angles

Several laundry washings were also applied using a commercial detergent to the

cationic glycerin treated fabric and % nitrogen content of the fabric were tested. The %

nitrogen content was initially 0.36%, after one laundry washing it was 0.36% and was

0.31% after five laundry washings and 0.24% after ten laundry washings.

76

4.2.4 Wrinkle recovery angles of cationic cellobiose and cationic dextrose treated

fabrics

As a prescreening study, we treated anionic fabrics with cationic cellobiose and

cationic dextrose. These polycations were investgated to identify if they could improve the

crease angle recovery of cellulosic fabrics. Table A.7 of the Appendix shows the results of

wrinkle recovery angle measurements of the untreated, carboxymethylated and treated

fabrics. The results show that even with 6% of polyelectrolyte solution the increase in

wrinkle recovery angles are lower than those obtained with cationic chitosan and cationic

glycerin treatments. The dry wrinkle recovery angles of cationic cellobiose treatments are

slightly higher than cationic dextrose treated fabrics while the wet wrinkle recovery angles

are almost identical.

4.2.5 Wrinkle recovery angles of calcium chloride and magnesium chloride treated

fabrics

The wrinkle recovery angles of untreated, carboxymethylated, calcium and

magnesium treated samples are shown in Table A.8 of the Appendix. Calcium (Ca++) and

magnesium (Mg++) are divalent metal atoms. Due to the two positive charges, they

potentially can form ionic crosslinks with the carboxymethyl groups on adjacent cellulose

polymer chains. The effects of carboxyl content of the fabrics on dry and wet wrinkle

recovery angles are shown in Figure 4.11 and 4.12. The treatments of anionic cellulosic

fabrics with calcium chloride and magnesium chloride also provide a significant

improvement in dry and wet wrinkle recovery angles for the treated fabrics. The results

77

obtained from both treatments were approximately the same. Calcium chloride treated

fabrics showed up to 244o dry and 232o wet crease angle recovery and the magnesium

chloride treated fabrics created a maximum of 232o dry and 237o wet wrinkle recovery

angles. The cellulosic fabric containing 114.5 mmole/100g carboxyl content was also

treated with 0.5M sodium chloride. The results of measurements are 165o for dry and 185o

for wet wrinkle recovery angles. Lower wrinkle recovery angles of sodium chloride

treated fabrics indicated that divalent metal atoms are needed in order to obtain high

crease angle recovery because they can form ionic crosslinks due to double positive

charges on them.

120

160

200

240

0 30 60 90 120

Carboxyl content (mmol/100g)

Dry

wrin

kle

reco

very

ang

les

(deg

rees

)

0%0.5M Ca++0.5M Mg++

Figure 4.11 Effect of carboxyl content on dry wrinkle recovery angles of calcium and

magnesium treated fabrics

78

120

160

200

240

0 30 60 90 120

Carboxyl content (mmol/100g)

Wet

wrin

kle

reco

very

ang

les

(deg

rees

)

0%0.5M Ca++0.5M Mg++

Figure 4.12 Effect of carboxyl content on wet wrinkle recovery angles of calcium and

magnesium treated fabrics

The paired t-test is applied to the data obtained with calcium and magnesium

treatments as previously described. [53] Table 4.3 shows the paired t-test results of

dry/wet wrinkle recovery angles of calcium and magnesium treatments for 95% CI. The

calculated µ values of these treatments are contained in the 95% confidence interval.

Therefore we are 95% confident with accepting Ho, therefore stating that the differences

between Ca++ and Mg++ treatments are not significant.

79

Table 4.3 Paired t-test results for dry/wet wrinkle recovery angles of Ca++ and Mg++ treated fabrics

95% CI Difference Mean of

Sample Difference(µ)

Standard Error DF

Lower

Limit

Upper

Limit

Dry WRA of Ca++ and Mg++

not significantly different 0.8 4.25910 4 -11.02517 12.6251

Wet WRA of Ca++ and Mg++

not significantly different -1.2 4.90306 4 -14.81307 12.4130

4.2.6 Discussion of wrinkle recovery angles for polycation treatments

The polyelectrolyte type, anionic content of the fabrics and application procedure

are the three major affects that influence the durable press properties of the treated fabrics.

Ionic crosslinks between cellulose chains stabilize the structure; therefore, fabrics resist

wrinkling. The treatments with cationic chitosan using different molecular weights,

concentrations and different application procedures produced different results. It was

expected that the smaller molecular weight cationic chitosan is able to produce higher

wrinkle recovery angles, but the change in molecular weight didn’t make a significant

difference. The result indicated that a wider range of molecular weight difference might

be needed. On average, the cationic chitosan produced from the chitosan having a

molecular weight of 3.2 x 104g/mole created slightly higher improvements for dry wrinkle

80

recovery angles than the other treatments. The results obtained by pair t-test also showed

that there is not a significant difference in wrinkle recovery angles between the three

different molecular weights of cationic chitosan treatments. The treatments with the

concentrations of 3% and 6% improve the wrinkle recovery angles more than treatment

with 1% concentration. There is also no significant difference between 3% and 6%

concentrations, but there was a slight increase in wrinkle recovery angles with increase in

the carboxyl content of the fabrics. It is believed to be result of having more ionic

crosslinks between cellulose chains, because each of the carboxyl groups can form an

ionic bond with the cationic sites of the crosslinkers.

With the pad batch and exhaustion treated fabrics a reasonably high wet crease

angle recovery was gained, but dry wrinkle recovery angles were very low. For some

cases, the dry angles were measured less than the untreated fabric. Yet, the fabric treated

with pad dry cure application method produced very high wet crease angle recovery and

reasonably high dry wrinkle recovery angle. Cationic glycerin treatment also showed high

wrinkle recovery angles. Just like the cationic chitosan treatment, the wet crease angle

recovery was higher. Both dry and wet wrinkle recovery angles were slightly higher than

cationic chitosan treatments. The different crosslinker concentrations produced

approximately the same results.

Fabrics treated with the exhaustion procedure showed lower crease angle recovery

than those treated with pad dry cure application. This implies that the curing step is

needed in order to accomplish high improvements in crease angle recovery of the treated

fabrics. The treatments with cationic cellobiose and cationic dextrose also improved the

81

crease angle recovery of the anionic cellulosic fabrics, although, the increases in wrinkle

recovery angles are not as high as cationic glycerin treatment. Calcium and magnesium

treatments produced the highest dry wrinkle recovery angles. The wet crease angle

recovery of the treated fabrics was lower than cationic chitosan and cationic glycerin

treatments. Increases in carboxyl content produced higher dry wrinkle recovery angles but

for wet crease angle recovery the 60.7mmole/100g carboxyl content gave the best result.

Unlike the DMDHEU treatment, for most of the polyelectrolyte treatments, the wet

wrinkle recovery angles were higher than dry crease angle recovery. This is the result of

forming the crosslinks at the wet stage of the fabric. If the ionic links were formed when

the fabric is dry then the dry crease angle recovery would be higher than the wet wrinkle

recovery angles. Hence, the treatments by exhaustion and pad batch procedures showed

high improvements in wet wrinkle recovery angles, but the dry crease angle recovery was

very poor. The fabrics treated with pad dry cure procedure produced significant

improvements in dry wrinkle recovery angles because of the curing step. When high

temperature was applied to the treated ionic fabrics, some of the ionic crosslinks between

the cellulose chains break and reform. This produces a higher dry crease angle recovery.

For example, a single divalent atom either calcium or magnesium, has higher mobility

between the cellulose polymer chains. Therefore, when fabrics were cured at high

temperatures, some of the ionic crosslinks may break and reform. Thus, when a force is

applied to the treated fabric while the fabric is dry the cellulose chains are able to recover.

As a result, higher dry wrinkle recovery angles are obtained. Hence, the dry crease angle

82

recoveries of calcium and magnesium treatments were higher than chitosan and glycerin

treatments.

4.3 Wrinkle recovery angles of polyanion treated cationic cellulosic fabrics

The effects of %Nitrogen fixed on the fabrics and crosslinker concentration on

wrinkle recovery angles of the treated fabrics are presented here. %Nitrogen fixed on the

cellulosic fabrics is given on the x-axis and dry or wet wrinkle recovery angles are given

on the y-axis.

4.3.1 Wrinkle recovery angles of PCA and BTCA treated fabrics

The results can be found in Tables A.9 and A.10 in the appendix. They illustrate

an increase in both dry and wet wrinkle recovery angles. Both of the treatments showed

that the wet wrinkle recovery angles are higher than dry. The effect of %Nitrogen fixed on

cellulosic fabric and PCA concentration on dry and wet wrinkle recovery angles are

shown in Figure 4.13 and 4.14. The untreated fabric treated with 6%PCA showed a dry

crease angle recovery of 192o. Such high value for untreated fabric appeared only one

time, therefore we believe it is not a result of the treatment, but it may be resulted from the

differences in fabric structure and measurement errors. A correlation between wet wrinkle

recovery angles and %Nitrogen fixed was also obtained for both treatments. Higher

%Nitrogen fixed onto cellulose produces a higher crease angle recovery. It should be

noted that a similar correlation has been obtained for polycation treated anionic fabrics.

An increase in concentration of the PCA also showed a positive affect on crease angle

83

recovery performance of the treated cationic fabrics. PCA treatments produced wet

wrinkle recovery angles between 140o and 235o while the dry crease angle recovery was

between 160o and 190o. Standard deviation of the wrinkle recovery angle measurements is

between 4o and 9o. On average, the difference of wet wrinkle recovery angles of the

blanks and treated fabrics are between 30o and 80o. The maximum wet wrinkle recovery

angle was obtained with 6% polyanion concentration applied onto the fabrics containing

1.54 %Nitrogen fixed.

120

140

160

180

200

0.2 0.6 1 1.4

%Nitrogen fixed

Dry

wrin

kle

reco

very

ang

les

(deg

rees

) 0%1%PCA3%PCA6%PCA

Figure 4.13 Effect of %Nitrogen fixed and concentration on dry wrinkle recovery angles

of PCA treated fabrics

84

120

160

200

240

0.2 0.6 1 1.4

%Nitrogen fixed

Wet

wrin

kle

reco

very

ang

les

(deg

rees

) 0%1%PCA3%PCA6%PCA

Figure 4.14 Effect of %Nitrogen fixed and concentration on wet wrinkle recovery angles

of PCA treated fabrics

For BTCA treatments the effect of %Nitrogen fixed on cellulosic fabric and

crosslinker concentration on dry and wet wrinkle recovery angles are shown in Figure

4.15 and 4.16. A correlation between wet wrinkle recovery angles and %Nitrogen fixed

was also obtained for BTCA treatments. Treatment of higher %Nitrogen fixed fabrics

produced higher wrinkle recovery angles. An increase in concentration of the BTCA also

resulted in higher crease angle recovery performance of the treated cationic fabrics.

BTCA treatments produced wet wrinkle recovery angles between 140o and 235o while the

dry crease angle recovery was between 155o and 185o. Standard deviation of the

measurements is in the range of 6o and 11o. On average, the difference of wet wrinkle

recovery angles of the blanks and treated fabrics are between 20o and 80o. The maximum

85

wet wrinkle recovery angles were also obtained with 6% polyanion concentration applied

onto the fabrics containing 1.54 %Nitrogen fixed.

120

140

160

180

200

0.2 0.6 1 1.4

%Nitrogen fixed

Dry

wrin

kle

reco

very

ang

les

(deg

rees

) 0%1%BTCA3%BTCA6%BTCA

Figure 4.15 Effect of %Nitrogen fixed and concentration on dry wrinkle recovery angles

of BTCA treated fabrics

86

120

160

200

240

0.2 0.6 1 1.4

%Nitrogen fixed

Wet

wrin

kle

reco

very

ang

les

(deg

rees

) 0%1%BTCA3%BTCA6%BTCA

Figure 4.16 Effect of% Nitrogen fixed and concentration on wet wrinkle recovery angles

of BTCA treated fabrics

Dry wrinkle recovery angles of the treated fabrics decrease while the wet crease

angle recovery increases. The wrinkle recovery angles of the treated fabrics were slightly

higher for polycarboxylic acid treatments. The paired t-test is also applied to the data

obtained with PCA and BTCA treatments as previously described. [53] Table 4.4 shows

the paired t-test results of dry/wet wrinkle recovery angles of PCA and BTCA treatments

for 95% CI. The calculated µ values of these treatments are contained in the 95%

Confidence Interval. Therefore we are 95% confident with accepting Ho, therefore stating

that the differences are not significant.

87

Table 4.4 Paired t-test results for dry/wet wrinkle recovery angles of PCA and BTCA treated fabrics

95% CI Difference Mean of

Sample Difference(µ)

Standard Error DF Lower

Limit

Upper

Limit

Dry WRA of PCA and BTCA

not significantly different 6.5333333 3.24824 14 -3.136188 16.2028

Wet WRA of PCA and BTCA

not significantly different 5.8 2.56013 14 0.3090588 11.2909

4.3.2 Wrinkle recovery angles of EDTA, NTA and HEDTA treated fabrics

These chelating agents have multiple anionic charges on their molecules;

therefore, they are expected to form ionic crosslinks with cationic sites of cellulose

polymer chains. This was also a prescreening study to identify if these molecules can

improve the durable press properties of cationic cellulosic fabric. The data can be obtained

from Tables A.11, A.12 and A.13 of the Appendix. As an example, the effect of EDTA

concentration and %Nitrogen content of the cationic fabrics on wrinkle recovery angles of

the treated fabrics is given in Figures 4.17 and 4.18 below. Wet wrinkle recovery angles

of the treated fabrics are higher than dry wrinkle recovery angles. The wet wrinkle

recovery angles are significantly lower than PCA and BTCA treatments. Both dry and wet

88

wrinkle recovery angles are under 190o, which indicates that these chelating agents don’t

have an advantage over PCA and BTCA.

120

140

160

180

200

0.2 0.6 1 1.4

%Nitrogen fixed

Dry

wrin

kle

reco

very

ang

les

(deg

rees

)

0%1%EDTA3%EDTA6%EDTA

Figure 4.17 Effect of %Nitrogen fixed and concentration on dry wrinkle recovery angles

of EDTA treated fabrics

89

120

140

160

180

200

0.2 0.6 1 1.4

%Nitrogen fixed

Wet

wrin

kle

reco

very

ang

les

(deg

rees

) 0%1%EDTA3%EDTA6%EDTA

Figure 4.18 Effect of %Nitrogen fixed and concentration on wet wrinkle recovery angles

of EDTA treated fabrics

4.3.3 Wrinkle recovery angles of oxalic acid, citric acid and malic acid treatments

As a prescreening study, we treated cationic fabrics with oxalic acid, malic acid

and citric acid. These acids have more than one anionic carboxyl group, therefore, they

can form ionic crosslinks with the cationic groups of the cellulose polymer chains. These

polyanions were analyzed to determine if they can improve the crease angle recovery of

cationic cellulosic fabrics. The results of wrinkle recovery angle measurements of the

untreated fabric, cationized fabrics and polyanion treated fabrics are shown in Table A.14

of the Appendix. The wet wrinkle recovery angles are under 205o and the dry wrinkle

recovery angles are under 160o. The results show that even with the 0.5M polyelectrolyte

solution, the increases in wrinkle recovery angles are lower than those obtained with PCA

and BTCA treatments.

90

4.3.4 Discussion of wrinkle recovery angles for polyanion treatments

We experimented with eight different polyanions, all of which improved the

wrinkle recovery angles of the cationic fabrics with varying degrees. Two of those

polyanions produced improvements in wrinkle recovery angles that surpassed the other

six. These two polyelectrolytes are PCA and BTCA. The chelating agents EDTA, NTA

and HEDTA treated cationic fabrics resulted in 20-30% increase in crease angle recovery.

On the other hand, BTCA and PCA increased 20-50% in wrinkle recovery angles. BTCA

has four carboxyl groups on its molecule. PCA, on the other hand has hundreds of

carboxylic groups that are available to form ionic crosslinks with the cationic cellulose

chains. Therefore, it is expected that PCA treated fabrics would have better durability. The

comparision of the polyanion treatments with the polycation treatments demonstrates that

the polycation treatments such as cationic chitosan and cationic glycerin improved the

durable press properties of the fabrics better than PCA and BTCA treatments. This could

be due to the bulky structure of quat molecules that attached on the chitosan or glycerin.

Hence, not only ionic attraction between the opposite charges, but also secondary forces

such as wan der walls forces may have affected the crosslinks between the cellulose

chains. The cationization process of the cellulose is also much more difficult than the

carboxymethylation, due to low efficiency of the reaction of cellulose with quat.

Therefore, polycation treatments of anionic cellulose are preferable.

The summary of the effects of treatment on dry and wet wrinkle recovery angles of

the treated fabrics is shown in Figures 4.19 and 4.20. The DMDHEU treatment produced

the highest dry wrinkle recovery angles (276 degrees), followed by magnesium and

91

calcium treatments. The lowest wrinkle recovery angles were obtained with BTCA treated

cationic fabrics. Cationic chitosan and cationic glycerin treatments produced greater wet

wrinkle recovery angles than other polyelectrolyte treatments and were slightly lower than

the crease angle recovery (266 degrees) of DMDHEU treated fabric. Calcium and

magnesium treatments produced higher wrinkle recovery angles than PCA and BTCA

treatments. The lowest wet crease angle recoveries were obtained with BTCA treatment.

Figure 4.19 Effect of treatment on dry wrinkle recovery angles

92

Figure 4.20 Effect of treatment on wet wrinkle recovery angles 4.4 Strength data

Strength tests were studied with anionic fabrics treated with cationic chitosan,

cationic glycerin, calcium chloride and magnesium chloride and cationic cotton treated

with PCA and BTCA. Other treatments did not give significant wrinkle recovery angle

improvements therefore the strength test was not applied to them.

4.4.1 Tensile strength of conventional durable press finished fabric

The DMDHEU treated fabric was tested for breaking strength in warp direction in

order to compare with the polyelectrolyte treated samples. The result breaking strength

was 14.53lb.

93

4.4.2 Strength data of polycation treated anionic cellulosic fabrics

The data for untreated and treated fabrics can be found in Table A.15, A.16, A.17,

A.18 and A.19 of the Appendix showing the breaking load (lb) of the fabrics in warp

direction. Strength testing of 350 treated samples revealed tensile strength increases of up

to 58%. Standard deviation of strength tests for treated samples was between 2-5Lb. The

effects of carboxyl content of the fabrics and polycation concentration on the breaking

strength of the treatments are shown in Figures 4.21, 4.22 and 4.23. As an example the

data obtained from the molecular weight of 1.4 x 105g/mole chitosan is given below. For

cationic chitosan treatments the concentrations of 3% and 6% crosslinker showed the

highest strength gains, though the difference between the two wasn’t significant. In some

cases, 6% treatment produced a lower strength gain than 3% treatment. The strength data

of three different molecular weights of cationic chitosan treatments did not show a

significant difference. The cationic glycerin treatment produced a better strength gain and

a better correlation between crosslinker concentration and the strength gain. The

maximum breaking load was obtained with the 3% treatment on 114.5mmole/100g fabric.

The calcium chloride and magnesium chloride treatments also showed some strength gain

but not as high as cationic chitosan and cationic glycerin treatments. The breaking

strengths of the treated fabrics are in the range of 41.6Lb and 55.1Lb. The maximum

breaking strength was obtained at 55.1Lb for magnesium chloride treated fabric

containing114.5mmol/100g carboxyl content while it was 52.2Lb for calcium chloride

treated fabric containing 87.1mmol/100g carboxyl content. There was also no correlation

between the strength and carboxyl content of the treated fabrics.

94

30

40

50

60

70

0 30 60 90 120

Cabrboxyl content (mmol/100g)

Bre

akin

g lo

ad (L

b)

0%1%CC3%CC6%CC

Figure 4.21 Effect of carboxyl content and concentration on breaking strength of the

cationic chitosan (molecular weight of 1.4 x 105g/mole) treated fabrics

95

30

40

50

60

70

80

0 30 60 90 120

Carboxyl content (mmol/100g)

Bre

akin

g lo

ad (L

b)

0%1%CG3%CG6%CG

Figure 4.22 Effect of carboxyl content and concentration on breaking strength of the

cationic glycerin treated fabrics

30

40

50

60

0 30 60 90 120

Carboxyl content (mmol/100g)

Bre

akin

g lo

ad (L

b)

0%0.5M Ca++0.5M Mg++

Figure 4.23 Effect of carboxyl content and concentration on breaking strength of the

calcium and magnesium treated fabrics

96

4.4.3 Strength data of polyanion treated cationic cellulosic fabrics

Cationic cellulosic fabrics treated with PCA and BTCA resulted in slight increase

in breaking strength. The data can be found in Tables A.20 and A.21 of the Appendix. The

effect of %Nitrogen fixed on fabrics and polyelectrolyte concentrations on the breaking

strength of the treated fabrics are presented in Figures 4.24 and 4.25. The breaking load

measurements are between 40Lb and 50Lb. Both polyanion treatments showed

approximately the same strength gain. The tensile strength test was applied to 150 samples

and only three samples showed strength losses of 7, 12 and 13% compared to the initial

fabric. The difference in strength gain was not significant between the PCA and BTCA

treatments. The 3% and 6% PCA treatments produced higher strength gains than 1% PCA

treatment. On the other hand, for BTCA treatments, 1% and 3% concentrations showed

higher strength gain than 6% concentration treatment. These treatments increased the

strength of the cellulosic fabric less than polycation treatments. On average polycation

treatments produced 24% more strength gain than polyanion treatments.

97

30

40

50

60

0.2 0.6 1 1.4

%Nitrogen fixed

Bre

akin

g lo

ad (L

b)

0%1%PCA3%PCA6%PCA

Figure 4.24 Effect of %Nitrogen content and concentration on breaking strength of the

PCA treated fabrics

30

40

50

60

0.2 0.6 1 1.4

%Nitrogen fixed

Bre

akin

g lo

ad (L

b)

0%1%BTCA3%BTCA6%BTCA

Figure 4.25 Effect of %Nitrogen content and concentration on breaking strength of the

BTCA treated fabrics

98

4.4.4 Discussion of strength data of untreated and treated fabrics

The ionic crosslinking process has a great ability to increase the strength of the

treated fabrics. This strength gain is proportional with number of ionic crosslinks between

the cellulose polymer chains. Unlike covalent bonds formed by treatment of fabric with

N-methylol based resins in conventional durable press finishing, the ionic crosslinks

increase the flexibility of the polymer chains, because the ionic crosslinked samples were

produced significantly higher elongation at breaking load than untreated and DMDHEU

treated fabrics. The average elongation of 5 untreated fabric samples at peak load was

5.2mm, while it was 2.52mm for DMDHEU treated fabrics and 26.8mm for 6% cationic

glycerin treated fabric containing 114.5 mmole/100g carboxyl groups. The flexible

polymer chains have mobility to line up and become firmer under an applied force. This

lining up of the polymer chains provides resistance against much higher forces. Hence, the

result is much higher increases in strength gain of treated fabrics.

Considering the strength loss by cationization of the fabrics, the data obtained from

polyanion treatments showed that there is a significant strength gain of up to 34%.

Cellulosic fabrics treated with strong acids could decrease the strength of the fabric. Thus

we neutralized the acids before the crosslinking process, with the intention of halting the

strength reducing effects of the strong carboxylic acids. The strength gain by polyanion

treatments was lower than polycation treatments, likely due to the acid treatments and

strength loss of the cationic fabrics. Treatments of anionic fabrics with various polycations

provided a strength gain up to 58%, a very significant improvement.

99

The summary of the strength data of the treated fabrics is shown in Figure 4.26. The

DMDHEU treatment decreased the tensile strength of the fabrics more than 50%, which is

a very significant strength loss. On the other hand the ionic crosslinked fabrics showed

strength gains up to 58%. The maximum strength gain obtained with cationic glycerin

treatment.

Figure 4.26 Effect of treatment on breaking strength

Figures 4.27 and 4.28 show the wet wrinkle recovery angles of cationic chitosan and PCA

treated samples versus breaking strength data. The correlations with the coefficients of

determination (R2) of 0.78 for cationic chitosan treatments and 0.49 for PCA treatments

100

are obtained. The correlation coefficients are calculated as 0.71 for cationic glycerin

treatments and 0.42 for BTCA treatments.

R2 = 0.78

200

220

240

260

280

40 50 60 70

Breaking load (Lb)

Wet

wrin

kle

reco

very

ang

les

(deg

rees

)

Figure 4.27 Correlation between wet wrinkle recovery angles of cationic chitosan

(molecular weight of 1.4 x 105g/mole) treatment and tensile strength

101

R2 = 0.49

130

150

170

190

210

230

250

30 35 40 45 50 55 60

Breaking load (Lb)

Wet

wrin

kle

reco

very

ang

les

(deg

rees

)

Figure 4.28 Correlation between wet wrinkle recovery angles of PCA treatment and

tensile strength

4.5 CIE whiteness index data

The CIE whiteness index measurements were applied to cationic chitosan, cationic

glycerine, calcium chloride and magnesium chloride treated anionic fabrics and PCA and

BTCA treated cationic fabrics.

4.5.1 CIE whiteness index of conventional durable press treated fabric

The whiteness index of DMDHEU treated fabric measured as 51.04 while it was

62.58 for untreated fabric. There was approximately 12% decrease in whiteness index for

resin treated fabric. It has known that the decrease in whiteness is due to high curing

temperature and presence of acid catalyst for the resin, because such conditions degrade

the cellulose and yellows the fabric.

102

4.5.2 CIE whiteness index of polycation treated anionic cellulosic fabrics

The CIE whiteness index data showed that all the treatments decrease the

whiteness of the fabric except calcium and magnesium chloride treatments. The data can

be found in Tables A.22, A.23, A.24, A.25 and A.26 of the Appendix. The effect of

carboxyl content of the fabrics and polyelectrolyte concentrations on the whiteness index

of the treated fabrics are presented in Figures 4.29, 4.30 and 4.31. The cationic chitosan

treatments decreased the whiteness index of the fabrics the most, due to the color of the

cationic chitosan. As previously mentioned, the color of the chitosan changes into a dark

brown color after reaction with quat. The greatest decrease was obtained with the

molecular weight of 3.2 x 104g/mole cationic chitosan. Treatments with higher

concentrations of crosslinker produced the lowest whiteness index. The cationic glycerin

treatments also created some decreases in whiteness index, but not as low as cationic

chitosan treatments with values between 50 and 60. The calcium and magnesium

treatments had almost no effect on whiteness of the fabrics. In some cases, they slightly

improved the whiteness index.

103

30

40

50

60

70

0 30 60 90 120

Carboxyl content (mmol/100g)

CIE

Whi

tene

ss In

dex

0%1%CC3%CC6%CC

Figure 4.29 Effect of carboxyl content and concentration on whiteness index of the

cationic chitosan (molecular weight of 1.4 x 105g/mole) treated fabrics

30

40

50

60

70

0 30 60 90 120

Carboxyl content (mmol/100g)

CIE

Whi

tene

ss In

dex

0%1%CG3%CG6%CG

Figure 4.30 Effect of carboxyl content and concentration on whiteness index of the

cationic glycerin treated fabrics

104

30

40

50

60

70

0 30 60 90 120

Carboxyl content (mmol/100g)

CIE

Whi

tene

ss In

dex

0%0.5M Ca++0.5M Mg++

Figure 4.31 Effect of carboxyl content and concentration on whiteness index of the

calcium chloride and magnesium chloride treated fabrics

4.5.3 CIE whiteness index of polyanion treated cationic cellulosic fabrics

The results can be found in Tables A.27 and A.28 of the appendix. The effect of

%Nitrogen content of the fabrics and polyelectrolyte concentrations on the whiteness

index of the treated fabrics are presented in Figures 4.32 and 4.33. The blank cationic

fabrics showed significant decreases in whiteness compared to untreated fabrics. Both of

the treatments reduced the whiteness of the fabrics with various degrees. The decreases

are quite similar to the cationic chitosan treatment results. The strong acidic nature of

these polycarboxylic acids yellows the cellulose, especially when the fabrics are

introduced to high temperatures. Although, BTCA decreased the whiteness index values

105

of the treated fabrics slightly more than PCA, the difference was not significant. An

increase in cationic levels of the fabric and concentration of the polyanion produced

higher decreases in the whiteness index of the treated fabrics.

30

40

50

60

70

0.2 0.6 1 1.4

%Nitrogen fixed

CIE

Whi

tene

ss In

dex

0%1%PCA1%PCA6%PCA

Figure 4.32 Effect of %Nitrogen fixed and concentration on whiteness index of the PCA

treated fabrics

106

30

40

50

60

70

0.2 0.6 1 1.4

%Nitrogen fixed

CIE

Whi

tene

ss In

dex

0%1%BTCA3%BTCA6%BTCA

Figure 4.33 Effect of %Nitrogen fixed and concentration on whiteness index of the BTCA

treated fabrics

4.5.4 Discussion of whiteness index of untreated and treated fabrics

The summary of the CIE whiteness index data of treated fabrics is shown in Figure

4.34. The whiteness index of DMDHEU treated fabric was 51.04, approximately 12%

decrease compared to untreated fabric. Cationic glycerin, calcium and magnesium

treatments produced higher whiteness index values than resin treatment but cationic

chitosan, PCA and BTCA treatments decreased the whiteness index of the treated fabrics

more than conventional resin treatment. The whiteness index of polyelectrolyte treated

fabrics decreases as the concentration of crosslinker increases. We also observed that the

decrease in whiteness index was higher for BTCA treatment. The change is more

significant for treatments of fabrics having higher levels of cationic or anionic content.

107

Hence, the density of the crosslinks between the cellulose polymer chains is higher. The

whiteness index of untreated fabric dropped from 62.58 to as low as 32.42 for cationic

chitosan treatments. The decrease is due to color change of cationic chitosan. Light

yellowish color of chitosan changes into dark brown color after the cationization reaction.

Though, the molecular weight of 3.2 x 104g/mole showed very low whiteness index values

for treatments with 3 and 6% concentrations with results of 51.77 for cationic glycerin

treatments, 37.25 for PCA treatments and 31.82 for BTCA treatments. The treatments

with calcium chloride and magnesium chloride did not decrease the whiteness index of the

fabrics significantly. In some cases they slightly increased the whiteness of the treated

fabrics.

108

Figure 4.34 Effect of treatment on whiteness index

4.6 Stiffness data

The stiffness test was applied to the fabrics treated with cationic chitosan, cationic

glycerin, calcium chloride, magnesium chloride, PCA and BTCA. The data is given in the

figures below. The figures show the ionic content of the fabric on the x-axis and the

flexural rigidity of the treated fabrics on the y-axis. The untreated fabric produced a

flexural rigidity of 21.47mg x cm and the flexural rigidity of the N-methylol treated fabric

measured as 39.04mg x cm.

109

4.6.1 Stiffness of conventional durable press treated fabrics

The bending length and flexural rigidity of the DMDHEU treated fabric was

measured as 1.5cm / 39.04mg x cm while it was 1.2cm / 21.4mg x cm for untreated fabric.

4.6.2 Stiffness data of polycation treated anionic cellulosic fabrics

The results containing the bending length and flexural rigidity of the untreated,

cationized and treated fabrics can be found in Tables A.29, A.30, A.31, A.32 and A.33 of

the appendix. The effect of carboxyl content of the fabrics and polyelectrolyte

concentrations on the stiffness of the treated fabrics are presented in Figures 4.35, 4.36

and 4.37. The cationic chitosan treatments showed higher flexural rigidity values for

treated fabrics. The rigidity of the fabrics increased significantly after the

carboxymethylation process. Molecular weight of 3.2 x 104g/mole cationic chitosan

produced the highest flexural rigidity values. Molecular weight of 1.4 x 105g/mole and

6.11 x 105g/mole cationic chitosan treated fabrics showed slightly lower rigidity values

than 3.2 x 104g/mole cationic chitosan treatment. For all cases though, cationic chitosan

treatments showed significantly higher rigidity values than other treatments. The rigidity

values of treated fabrics are in the range of 47mg x cm to 730mg x cm. The cationic

glycerin treated fabrics showed lower flexural rigidity values than cationic chitosan

treatments. The flexural rigidity values are between 45mg x cm and 165mg x cm. On the

other hand, the calcium chloride treated fabrics showed flexural rigidity between 80mg x

cm and 200mg x cm, while it was between 90 to 240mg x cm for magnesium chloride

treatments.

110

0

50

100

150

200

250

300

0 30 60 90 120

Carboxyl content (mmole/100g)

Flex

ural

rigi

dity

(mg

x cm

)

0%1%CC3%CC6%CC

Figure 4.35 Effect of carboxyl content and concentration on stiffness of the cationic

chitosan (molecular weight of 1.4 x 105g/mole) treated fabrics

0

50

100

150

200

250

300

0 30 60 90 120

Carboxyl content (mmole/100g)

Flex

ural

rigi

dity

(mg

x cm

)

0%1%CG3%CG6%CG

Figure 4.36 Effect of carboxyl content and concentration on stiffness of the cationic glycerin treated fabrics

111

0

50

100

150

200

250

300

0 30 60 90 120

Carboxyl content (mmole/100g)

Flex

ural

rigi

dity

(mg

x cm

)

0%0.5M Ca++0.5M Mg++

Figure 4.37 Effect of carboxyl content and concentration on stiffness of the calcium

chloride and magnesium chloride treated fabrics

4.6.3 Stiffness data of polyanion treated cationic cellulosic fabrics

The results of stiffness measurements of PCA and BTCA treated fabrics are given

in Tables A.34 and A.35 of the appendix. The effect of %Nitrogen content of the fabrics

and polyelectrolyte concentrations on stiffness of the treated fabrics are presented in the

Figures 4.38 and 4.39. The cationized cellulosic fabrics also showed significantly higher

flexural rigidity values compared to the untreated fabric. The rigidity of the fabrics

increased while increasing the cationic level of the fabrics. The maximum rigidity was

obtained with 0.57 %Nitrogen fixed fabric. The treatments with polyanions reduced the

rigidity of the cationized fabrics. The crosslinked fabrics’ rigidity values are slightly

higher than that of the untreated fabric. Both the PCA and BTCA treatments produced

112

similar flexural rigidity values. For the PCA treatments, the flexural rigidity values are

between 22 and 73mg x cm, while for BTCA treatments they were between 23 and 72mg

x cm.

0

50

100

150

200

250

300

0.2 0.6 1 1.4

%Nitrogen fixed

Flex

ural

rigi

dity

(mg

x cm

)

0%1%PCA3%PCA6%PCA

Figure 4.38 Effect of %Nitrogen fixed and concentration on stiffness of the PCA treated

fabrics

113

0

50

100

150

200

250

300

0.2 0.6 1 1.4

%Nitrogen fixed

Flex

ural

rigi

dity

(mg

x cm

)

0%1%BTCA3%BTCA6%BTCA

Figure 4.39 Effect of %Nitrogen fixed and concentration on stiffness of the BTCA treated fabrics

4.6.4 Discussion of stiffness data of untreated and treated fabrics

The summary of the stiffness data of treated fabrics is shown in Figure 4.40. The

flexural rigidity of the DMDHEU treated fabric was measured as 39.04mg x cm while it

was 21.4mg x cm for untreated fabric. The stiffness of resin treated fabric is lower than

most of the ionic crosslinked fabrics. But in some cases, for example the PCA and BTCA

treated cationic fabrics having 0.19% and 0.28% fixed nitrogen showed lower flexural

rigidity than DMDHEU treated fabric.

The ionic crosslinking process increases the stiffness of the treated fabric. After

the fabric is carboxymethylated or cationized it shows significantly high flexural rigidity

114

values compared to the untreated fabric, because ionic cellulose molecules have

substitutions on their molecules either with chloroacetic acid or CHTAC. Cellulose

molecules are most extended at low concentrations of ionic groups but at higher

concentrations the molecules overlap and coil up and then, at high concentrations, they

form entangled structures. Increasing ionic strength causes the polymer to become more

coiled. This new molecular structure makes the fabric stiffer. Following application, ionic

crosslinking in this case, reduces the rigidity of the ionic cellulosic fabric by some degree.

The end product, crosslinked cellulosic fabric, shows rigidity values that are still higher

than the initial fabric. The increase in the flexural rigidity is higher for higher cationic or

anionic content of the fabrics. Increases in the concentration of the crosslinker also make

the fabrics stiffer. In the case of anionic fabrics treated with polycations, the cationic

chitosan treatments produced the highest increase in stiffness. Calcium and magnesium

treated fabrics also produced high rigidity values, though are not as high as cationic

chitosan treated fabrics. Cationic glycerin treatments also showed significantly high

flexural rigidity values, but are still lower than cationic chitosan treatments. On the other

hand, the polyanion treated cationic fabrics showed flexural rigidity values that are

slightly higher than the initial fabric. The flexural rigidity values are almost identical for

PCA and BTCA treated fabrics. These treatments resulted with significantly low rigidity

values compared to polycation treated anionic fabrics.

115

Figure 4.40 Effect of treatment on stiffness

116

5. CONCLUSIONS

Ionic crosslinking of cellulose for durable press finish can be a potential solution

for today’s textile industry, which is searching for durable press finishes that can give the

same advantages as formaldehyde based finishes without causing strength loss and

formaldehyde release. There are many alternatives for forming ionic crosslinks, for

example, making cellulose anionic with chloro acetic acid and reacting with a polycation

or producing cationic cellulose with 3-chloro-2-hydroxypropyl trimethyl ammonium

chloride and then reacting with a polyanion. In both ways, the polymer chains are bound

at as many sites as possible with having an excellent washing durability. These treatments

produce improvements in both dry and wet wrinkle recovery angles with significant

increases in tensile strength. Increases up to 140o were obtained in wet wrinkle recovery

angles and up to 100o in dry wrinkle recovery angles, while including a considerable

strength gain in treated fabrics. The DMDHEU treatment decreased the tensile strength of

the fabrics more than 50%, a considerable strength loss and a major problem. On the other

hand the ionic crosslinked fabrics improved tensile strength of treated fabrics up to 58%, a

very significant strength gain. The whiteness index of resin treated fabric was 51.04, an

approximately 12% decrease compared to untreated fabric. Treatments with cationic

glycerin, calcium and magnesium did not cause significant decrease in whiteness index of

treated fabrics. The difference was between 2% and 20%. Cationic chitosan treatments

showed over 25% decreases in whiteness of the treated fabrics. The stiffness values of the

treated fabrics were significantly higher than initial fabric. The BTCA and PCA

117

treatments showed similar stiffness values to that of the DMDHEU treatment. The other

polyelectrolyte treatments produced significantly higher stiffness values than DMDHEU

treated fabric.

In addition, ionic crosslinks may have other important advantages, such as

antimicrobial activity and enhanced dyeability. The chemicals are common industrial

reactants and do not have unusual safety or environmental issues. The processes use

existing equipment that are widely used in the textile industry and have no need for high

temperature curing.

118

6. RECOMMENDATIONS FOR FUTURE WORK

This research focused on effects of altering polyelectrolyte types, ionic content of

the fabrics and application process on wrinkle recovery angles, tensile strength, whiteness

and stiffness of the treated fabrics.

In terms of polyelectrolyte types, we observed that small molecular weight

molecules such as cationic glycerin could give same advantages as high molecular weight

polyelectrolyte without causing significant decreases in whiteness of the treated fabrics. In

addition, it is expected that smaller molecules have higher mobility between the cellulose

polymer chains; therefore they could form ionic crosslinks either in the same cellulose

chain or between two different chains. The nitrogen analysis after several laundry

washings showed there was no significant difference in loss of polyelectrolyte between

cationic chitosan treatment and cationic glycerin treatment. Thus treatments with small

molecular weight polyelectrolyte are recommended for future work.

In the case of ionic content of the fabrics, four ionic levels have been tested and an

optimum level was observed. The wrinkle recovery angles and strength data of the treated

fabrics were not significantly different for levels 3 and 4. Meanwhile, treated fabrics

having lower levels of ionic contents produced higher whiteness and lower stiffness

values than the fabrics having higher ionic contents. Therefore, it is recommended to work

with just three different levels of ionic contents. Working with different fabric and fiber

types may also vary the results. For example, a tight fabric structure can produce lower

improvements than a loose fabric, as the tight weave inhibits movements causing the

119

fibers to take on more pressure, and therefore more wrinkling occurs. Fiber thickness also

affects the crease angle recovery of the fabric. For example, a fabric made of thicker fibers

may show lower crease angle recovery improvements, as the cellulose chains have greater

force difference due to stretching under an applied force and they wrinkle more.

The application process consisted of producing anionic and cationic cellulose

followed by the application of a polyelectrolyte of the opposite charge. The treatments of

anionic cellulosic fabrics with various polycations showed greater improvements.

Therefore, polycation application is preferable. A one-step treatment can also be applied,

such as making a precondensate by adding an ionic material to a polyelectrolyte of the

opposite charge and then reacting this precondensate with the fabric. This method is much

easier and faster, as it avoids the production of ionic fabric prior to ionic crosslinking and

is similar to conventional durable press finishes. In order to accomplish higher dry wrinkle

recovery angles, a solvent system can be used instead of water to apply polyelectrolytes.

The selected solvent should easily dissolve the polyelectrolytes and open the structure of

cellulose.

The ionic crosslinking process may have some effects on the microstructure of the

cellulose polymer chains, such as changes in the crystalline structure of the polymer

chains and internal structure of the cellulose. A further understanding of the molecular

changes after the ionic crosslinking process is recommended. Ionic crosslinking may

increase the crystalline part of the cellulose structure. The strength data obtained from

treated fabrics showed significant strength gain. This strength gain may be due to an

increase in the amount of crystalline part of cellulose structure. There are instrumental

120

techniques to determine the crystallinity level of the polymer. X-Ray diffraction analysis

can be performed to identify the changes in the crystallinities and the internal structures as

a result of ionic crosslinking.

121

7. LIST OF REFERENCES

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11. Butnaru R., Muresanu A. and Mitu S. Influence of crease resist finish treatments upon the comfort indices in cotton-type textiles. Cellulose Chemistry and Technology 1986 May;20(3):349-355. 12. Ibrahim N.A. and El Alfy EA. Concurrent dyeing and finishing II. Combined dyeing and easy-care finishing of aminized cotton with acid dyestuffs and N-methylol compounds. Cellulose Chemistry and Technology 1987 Sep;21(5):507-512. 13. Vaidya A.A. and Trivedi S.S. Textile Auxiliaries and Finishing Chemicals. Ahmedabad: R.C. Vora; 1975. 90-100. 14. Bajaj P., Chakrapani S. and Jha N.K. Flame retardant durable-press finishes for cotton and polyester/cellulose blends. Textile Research Journal 1984 Sep;54(9):619-630. 15. Shin Y., Hollies N.R.S. and Yeh K. Polymerization-crosslinking of cotton fabric for superior performance properties. I. A preliminary study. Textile Research Journal 1989 Nov;59(11)635-642. 16. Hamalainen C., Mard H.S. and Cooper A.S. Comparison of application techniques for deposition of resins in cotton fibres. American Dyestuff Reporter 1972 ;71(2):30-38. 17. Vail S.L. and Verburg G.B. Chemical and physical properties of cotton modified by N-methylol agents. III. Observations on polymerization and crosslinking of melamine- based reagents with cotton. Textile Research Journal 1973 Jan;43(2):67-74. 18. Nair P. Resin finishing of polynosic/cotton blended fabric by poly-set process. Cellulose Chemistry and Technology 1982 Sep;16(5):491-502. 19. Reinhardt R.M. and Harper R.J. Comparison of aftertreatments to lower formaldehyde release from cottons crosslinked with various finishing agents. Journal of Coated Fabrics 1984 April;13(4):216-227. 20. Sarma G.V., Gupta R.C. and Verma B.C. Performance report of BIL-treated all cotton durable press shirts in a pilot service test. Journal of the Textile Association 1973 May;34(3):115-122. 21.Turner J.D. Articles with durable press produced by low temperature treatment. Textile World 2001 March;151(3):50-53. 22. Yang C.Q., Qian L. and Lickfield G.C. Mechanical strength of durable press finished cotton fabric Part IV: Abrasion resistance. Textile Research Journal 2001 June;71(6):543-548.

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23. Charles Q. Yang and Weishu Wei. Mechanical Strength of Durable Press Finished Cotton Fabric Part II: Change in Cellulose Molecular Weight. Textile Research Journal 2000 Oct;70(10):910-915. 24. Ibrahim N. A., Abo Shosha M. H., Elnagdy E. I. and Gaffar M. A. Eco Friendly Durable Press Finishing of Cellulose Containing Fabrics. Journal of Applied Polymer Science 2002 June;84(12):2243–2253. 25. Day M.P. and Collier B.J. Prediction of formaldehyde release from durable press treated fabrics. Textile Chemist and Colorist 1997 Jan;29(1):33-36. 26. Xu W. and Li Y. Cotton fabric strength loss from treatment with polycarboxylic acids for durable press performance. Textile Research Journal 2000 Nov;70(11):957-961. 27. Charles Q. Yang and Weishu Wei. Mechanical strength of durable press finished cotton fabric. Part II: Comparison of crosslinking agents with different molecular structures and reactivity. Textile Research Journal 2000 Feb;70(2):143-147. 28. Srichharussin W., Ryo Aree W., Intasen W. and Poungraksakirt S. Effect of Boric Acid and BTCA on Tensile Strength Loss of Finished Cotton Fabrics. Textile Research Journal 2004 June;74(6):475-480. 29. Udomkichdecha W., Kjttinaovarat S., Tianasoonthornroek U. and Potlyaraj P. Acrylic and maleic acids in nonformaldehyde durable press finishing of cotton fabric. Textile Research Journal 2003 May;73(5):401-406. 30. Aly A.S., Hashem A. and Hussein S.S. Utilization of chitosan citrate as crease-resistant and antimicrobial finishing agent for cotton fabric. Indian Journal of Fiber & Textile Research 2004 June;29(2):218-222. 31. Achwal W.B. Chitosan and its derivatives for textile finishing. Colourage 2003 ;50(8): 51-76. 32. Gary A. Ungefug and Stephan B. Cello. Ionic Crosslinking of Acrylic Sizes. Textile Chemist and Colorist 1983 Oct;15(10):193-196. 33. Fujiyama M., Kondou M., Ayama K. and Inata H. Rheological Properties of Ionically and Covalently Crosslinked Polypropylene Type Thermoplastic Elastomers. Journal of Applied Polymer Science 2002 July;85(4):762–773. 34. Mitsuyoshi F., Kazuhiro Y., Kazuhiko A. and Hitoshi I. Rheological Properties of Ionically Crosslinked Poly(propylene)-Type Thermoplastic Elastomers. Journal of Applied Polymer Science 2002 Dec;86(11):2887–2897.

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35. Fanbao M., Baoyan Z., Lumei L. and Baoling Z. Liquid-crystalline elastomers produced by chemical crosslinking agents containing sulfonic acid groups. Polymer 2003 June;44(14):3935–3943. 36. Ibarra L. and Alzorriz M. Vulcanization of carboxylated nitrile rubber (XNBR) by a mixed zinc peroxide–sulphur system. Polymer International 2000 Jan;49(1):115-121. 37. Sriram V., Aruna P., Naresh M. D. and Radhakrishnan Ganga. AB Crosslinked Polyurethanes Through Ionic Crosslinking: Influence of Crosslinking Networks on Physico Chemical properties. Journal of Macromolecular Science Part A: Pure Application Chemistry 2001 Sep;38(9):945–959. 38. Roberts G.A.F. Chitin Chemistry. London: Macmillan Press Ltd.; 1992. 94-112. 39. Kim, Y., Choi, H., and Yoon, J. Synthesis of a Quaternary Ammonium Derivative of Chitosan and Its Application to a Cotton Antimicrobial Finish. Textile Research Journal 1998 June;68(6):428. 40. El Hilw Z.H. Development of an ecological system for the easy-care finishing of cotton. Tinctoria 2004 March;101(3):29-35. 41. Kittinaovarut S. Acrylic and citric acid in nonformaldehyde durable press finishing on cotton fabric. AATCC Review 2003;3:62-64. 42. Hasem M., Hauser P. and Smith B. Reaction Efficiency for Cellulose Cationization Using 3-Chloro-2-Hydroxypropyl Trimethyl Ammonium Chloride. Textile Research Journal 2003 Nov;73(11):1017-1023. 43. Shore John, editor. Colorants and Auxiliaries Organic chemistry and application properties. Hampshire: Hobbs The Printers; 2002. 664-666. 44. Timell T.E. editor. Proceedings of the Eighth Cellulose Conference. II. General Papers. New York: John Wiley & Sons; 1975. 811-830. 45. Tae K., Kim S., Han Y. and Young A.S. Effect of reactive anionic agent on dyeing of cellulosic fibers with a Berberine colorant. Dyes and Pigments 2004 March;60(3):121-127. 46. Lamber J.B., Shurrel H.F., Lightner D.A. and Cooks R.A. Introduction to Organic Spectroscopy. New York: Macmillan Publishing Company; 1987. 22-70.

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126

8. APPENDIX

8.1 Wrinkle recovery angles

The wrinkle recovery angles of the untreated fabric, carboxylated fabrics,

cationized fabrics, conventional durable press finished fabric and polyelectrolyte treated

fabrics and their relationships with ionic content of the fabrics and polyelectrolyte

concentration are given in the tables below.

Table A.1 Dry and wet wrinkle recovery angles for molecular weight of 32000g/mole cationic chitosan treated fabrics (dry/wet)

CC treatment > pad batch concentration Resin treatment 272/266

COO- content

(mmol/100g)

0%(Blank) 1% 3%

6%

6.2 138/125 184/168 172/172 178/168

30.2 160/149 212/236 242/250 226/255

60.7 163/145 220/244 234/246 222/257

87.1 162/153 224/248 232/248 230/242

114.5 166/159 220/250 234/254 208/268

127

Table A.2 Dry and wet wrinkle recovery angles for molecular weight of 140000g/mole cationic chitosan treated fabrics (dry/wet)

CC treatment > pad batch concentration Resin treatment 272/266

COO- content

(mmol/100g)

0%(Blank) 1% 3%

6%

6.2 138/125 186/185 172/182 183/193

30.2 160/149 204/234 208/246 211/256

60.7 163/145 212/244 218/258 214/256

87.1 162/153 228/246 222/260 209/260

114.5 166/159 212/260 207/264 215/266

Table A.3 Dry and wet wrinkle recovery angles for molecular weight of 611000g/mole cationic chitosan treated fabrics (dry/wet)

CC treatment > pad batch concentration Resin treatment 272/266

COO- content

(mmol/100g)

0%(Blank) 1% 3%

6%

6.2 138/125 170/172 164/166 168/164

30.2 160/149 208/246 212/252 212/250

60.7 163/145 210/249 215258 218/256

87.1 162/153 222/252 218/262 230/258

114.5 166/159 233/242 234/237 230/244

128

Table A.4 Dry and wet wrinkle recovery angles for molecular weight of 140000g/mole cationic chitosan treated fabrics by exhaustion method (dry/wet)

CC treatment > batch concentration Resin treatment 272/266

COO- content

(mmols/100g)

0%(Blank) 6%

30.2 160/149 135/216

87.1 162/153 123/191

114.5 166/159 120/232

Table A.5 Dry and wet wrinkle recovery angles for cationic glycerin treated fabrics (dry/wet)

Cationic glycerin treatment > pad batch concentration Resin treatment: 272/266

COO- content

(mmol/100g)

0% (Blank) 1% 3%

6%

6.2 138/125 188/185 174/183 185/192

30.2 160/149 216/250 206/256 207/257

60.7 163/145 201/256 208/262 212/265

87.1 162/153 215/259 215/258 204/265

114.5 166/159 214/269 227/266 224/273

129

Table A.6 Dry and wet wrinkle recovery angles for cationic glycerin treated fabrics by exhaustion method (dry/wet)

Cationic glycerin treatment > batch concentration Resin treatment: 272/266

COO- content

(mmol/100g)

0% (Blank) 12%

6.2 138/125 131/180

30.2 160/149 192/202

60.7 163/145 197/214

87.1 162/153 206/215

114.5 166/159 200/229

Table A.7 Dry and wet wrinkle recovery angles for cationic cellobiose and cationic

dextrose treated fabrics (dry/wet)

Cationic cellobiose and dextrose treatment > pad batch concentration Resin treatment: 272/266

COO- content

(mmol/100g)

0% (Blank) 6% cationic

cellobiose

6% cationic dextrose

30.2 160/149 212/214 202/216

60.7 163/145 208/214 205/215

130

Table A.8 Dry and wet wrinkle recovery angles for calcium chloride and magnesium

chloride treated fabrics (dry/wet)

Calcium and Magnesium chloride treatment > pad batch concentration Resin treatment: 272/266

COO- content

(mmol/100g)

0% (Blank) 0.5M Calcium

Chloride

0.5M Magnesium

Chloride

6.2 138/125 175/152 183/167

30.2 160/149 211/203 221/206

60.7 163/145 133/232 230/237

87.1 162/153 226/225 219/210

114.5 166/159 244/203 232/201

Table A.9 Dry and wet wrinkle recovery angles for PCA treated fabrics (dry/wet)

Polycarboxylic acids treatment > pad batch concentration Resin treatment 272/266

%N fixed 0%(Blank) 1% 3%

6%

0.24 138/125 172/144 158/150 192/132

0.45 155/158 175/191 168/191 172/178

0.73 157/145 185/178 188/195 184/187

1.15 150/154 184/207 184/202 174/222

1.54 153/152 182/222 170/226 170/232

131

Table A.10 Dry and wet wrinkle recovery angles for BTCA treated fabrics (dry/wet)

BTCA treatment > pad batch concentration Resin treatment: 272/266

%N fixed 0%(Blank) 1% 3%

6%

0.24 138/125 170/138 162/150 156/138

0.45 155/158 162/180 174/193 185/180

0.73 157/145 184/178 184/186 181/178

1.15 150/154 172/201 160/209 158/194

1.54 153/152 186/204 158/208 168/233

Table A.11 Dry and wet wrinkle recovery angles for EDTA treated fabrics (dry/wet)

EDTA treatment > pad batch concentration Resin treatment: 272/266

%N fixed 0%(Blank) 1% 3%

6%

0.24 138/125 162/134 191/128 176/137

0.45 155/158 166/168 166/158 161/161

0.73 157/145 163/168 184/187 173/182

1.15 150/154 145/183 157/174 157/179

1.54 153/152 136/189 134/182 165/185

132

Table A.12 Dry and wet wrinkle recovery angles for NTA treated fabrics (dry/wet)

NTA treatment > pad batch concentration Resin treatment: 272/266

%N fixed 0%(Blank) 1% 3%

6%

0.24 138/125 170/131 167/136 168/138

0.45 155/158 171/178 193/178 166/180

0.73 157/145 191/169 174/167 170/169

1.15 150/154 164/170 170/172 163/176

1.54 153/152 147/182 134/186 153/192

Table A.13 Dry and wet wrinkle recovery angles for HEDTA treated fabrics (dry/wet)

HEDTA treatment > pad batch concentration Resin treatment: 272/266

%N fixed 0%(Blank) 1% 3%

6%

0.24 138/125 182/136 176/130 186/130

0.45 155/158 173/170 167/160 175/158

0.73 157/145 187/170 184/187 191/186

1.15 150/154 148/180 146/178 157/182

1.54 153/152 160/188 161/183 139/186

133

Table A.14 Dry and wet wrinkle recovery angles for oxalic, malic and citric acid treated fabrics (dry/wet)

Oxalic acid, malic acid and citric acid treatment > pad batch concentration

Resin treatment: 272/266

%N fixed 0% (blank) 0.5M Oxalic

acid

0.5M Malic

acid

0.5M Citric

acid

1.15 150/154 160/178 154/170 160/182

1.54 150/152 106/186 140/188 154/204

8.2 Breaking strength

The breaking strength of the untreated fabric, carboxylated fabrics, cationized

fabrics, conventional durable press finished fabric and polyelectrolyte treated fabrics and

their relationships with ionic content of the fabrics and polyelectrolyte concentration are

given in the tables below.

134

Table A.15 Breaking strength data for molecular weight of 32000g/mole cationic chitosan

treated fabrics (lb)

CC treatment > pad batch concentration Resin treatment: 14.53

COO- content

(mmols/100g)

0%(Blank) 1% 3%

6%

6.2 39.01 41.76 45.7 46.1

30.2 53.32 63.68 63.6 59.8

60.7 45.99 62.6 65.8 62.1

87.1 44.8 61.1 57.5 62.6

114.5 51.23 49.8 66.4 70.1

Table A.16 Breaking strength data for molecular weight of 140000g/mole cationic chitosan treated fabrics (lb)

CC treatment > pad batch concentration Resin treatment: 14.53

COO- content

(mmols/100g)

0%(Blank) 1% 3%

6%

6.2 39.01 48.85 49.06 50.02

30.2 53.32 47.07 58.16 55.54

60.7 45.99 50.3 62.37 56.6

87.1 44.8 56.95 64.4 62.37

114.5 51.23 59.54 67.64 62.9

135

Table A.17 Breaking strength data for molecular weight of 611000g/mole cationic chitosan treated fabrics (lb)

CC treatment > pad batch concentration Resin treatment: 14.53

COO- content

(mmol/100g)

0%(Blank) 1% 3%

6%

6.2 39.01 46.9 46 47.9

30.2 53.32 62.7 64.9 55.6

60.7 45.99 65.6 53.6 58.8

87.1 44.8 66.9 62.2 58.6

114.5 51.23 57.8 57.3 53.2

Table A.18 Breaking strength data for cationic glycerin treated fabrics (lb)

Cationic glycerin treatment > pad batch concentration Resin treatment: 14.53

COO- content

(mmol/100g)

0% (Blank) 1% 3%

6%

6.2 39.01 52.67 56.4 55.16

30.2 53.32 58.85 66.53 64.67

60.7 45.99 66.2 67.26 66.3

87.1 44.8 62.17 70.78 66.96

114.5 51.23 65.45 73.53 66.93

136

Table A.19 Breaking strength data for calcium chloride and magnesium chloride treated fabrics (lb)

Calcium and Magnesium chloride treatment > pad batch concentration Resin treatment: 14.53

COO- content

(mmol/100g)

0% (Blank) 0.5M Calcium

Chloride

0.5M Magnesium

Chloride

6.2 39.01 43.8 44.3

30.2 53.32 51.8 42.8

60.7 45.99 47.2 41.6

87.1 44.8 52.2 47.7

114.5 51.23 51.7 55.1

Table A.20 Breaking strength data for PCA treated fabrics (lb)

Polycarboxylic acids treatment > pad batch concentration Resin treatment: 14.53

%N fixed 0%(Blank) 1% 3%

6%

0.24 39.01 39.31 41.01 41.86

0.45 41.47 36.08 46.15 45.68

0.73 36.32 39.5 45.53 45.66

1.15 36.2 40.78 47.41 46.35

1.54 35.38 52.75 50.94 49.22

137

Table A.21 Breaking strength data for BTCA treated fabrics (lb)

BTCA treatment > pad batch concentration Resin treatment: 14.53

%N fixed 0%(Blank) 1% 3%

6%

0.24 39.01 40.01 39.08 41.12

0.45 41.47 41.9 41.84 38.64

0.73 36.32 40.11 40.84 39.54

1.15 36.2 44.75 45.05 39.85

1.54 35.38 54.52 52.43 50.09

8.3 CIE whiteness index

The CIE whiteness index of the untreated fabric, carboxylated fabrics, cationized

fabrics, conventional durable press finished fabric and polyelectrolyte treated fabrics and

their relationships with ionic content of the fabrics and polyelectrolyte concentration are

given in the tables below.

138

Table A.22 Whiteness index data for molecular weight of 3.2 x 104g/mole cationic chitosan treated fabrics

CC treatment > pad batch concentration Resin treatment: 51.04

COO- content

(mmol/100g)

0%(Blank) 1% 3%

6%

6.2 62.58 49.35 42.44 40.51

30.2 60 41.32 33.35 28.55

60.7 59.64 37.44 26.12 20.46

87.1 58.71 34.44 6.58 4.34

114.5 57.84 21.11 2.5 2

Table A.23 Whiteness index data for molecular weight of 1.4 x 105g/mole cationic

chitosan treated fabrics

CC treatment > pad batch concentration Resin treatment 51.04

COO- content

(mmol/100g)

0%(Blank) 1% 3%

6%

6.2 62.58 57 56.97 55.75

30.2 60 54.5 53.31 52.12

60.7 59.64 53.91 50.27 49.56

87.1 58.71 51.59 46.77 44.28

114.5 57.84 47.49 41.1 33.42

139

Table A.24 Whiteness index data for molecular weight of 6.11x 105g/mole cationic chitosan treated fabrics

CC treatment > pad batch concentration Resin treatment: 51.04

COO- content

(mmol/100g)

0%(Blank) 1% 3%

6%

6.2 62.58 56.4 55.21 54.48

30.2 60 51.02 49 45.62

60.7 59.64 50.59 47.04 42.59

87.1 58.71 53.23 45.44 41.13

114.5 57.84 42.11 36.8 35

Table A.25 Whiteness index data for CG treated fabrics

CG treatment > pad batch concentration Resin treatment 51.04

COO- content

(mmol/100g)

0% (Blank) 1% 3%

6%

6.2 62.58 60.75 59.78 57.73

30.2 60 56.18 55.76 56.7

60.7 59.64 55.94 53.76 56.8

87.1 58.71 56.27 53.3 57.2

114.5 57.84 54.79 51.77 53.63

140

Table A.26 Whiteness index data for calcium and magnesium chloride treated fabrics

Calcium and Magnesium chloride treatment > pad batch concentration Resin treatment: 51.04

COO- content

(mmol/100g)

0% (Blank) 0.5M Calcium

Chloride

0.5M Magnesium

Chloride

6.2 62.58 60.98 60.29

30.2 60 61.02 60.94

60.7 59.64 62.8 62.21

87.1 58.71 63.6 61.54

114.5 57.84 60.52 60.77

Table A.27 Whiteness index data for PCA treated fabrics

Polycarboxylic acids treatment > pad batch concentration Resin treatment 51.04

%N fixed 0%(Blank) 1% 3%

6%

0.24 62.58 58.23 59.37 61.40

0.45 61.18 53.63 54.87 52.65

0.73 59.53 51.08 51.50 51.75

1.15 55.4 40.84 41.34 43.57

1.54 44.75 37.25 39.5 37.96

141

Table A.28 Whiteness index data for BTCA treated fabrics

BTCA treatment > pad batch concentration Resin treatment 51.04

%N fixed 0%(Blank) 1% 3%

6%

0.24 62.58 58.81 58.80 59.42

0.45 61.18 48.01 50.18 43.75

0.73 59.53 47.89 45.65 41.17

1.15 5534 43.19 43.15 39.13

1.54 44.75 38.21 31.82 39.69

8.4 Stiffness

The stiffness of the untreated fabric, carboxylated fabrics, cationized fabrics,

conventional durable press finished fabric and polyelectrolyte treated fabrics and their

relationships with ionic content of the fabrics and polyelectrolyte concentration are given

in the tables below.

142

Table A.29 Stiffness data for molecular weight of 3.2 x 104g/mole cationic chitosan treated fabrics Bending length (cm) / Flexural rigidity (mg x cm)

CC treatment > pad batch concentration Resin treatment: 1.5/39.04

COO- content

(mmol/100g)

0%(Blank) 1% 3%

6%

6.2 1.2/21.4 1.7/60.4 1.8/65 1.8/65.7

30.2 1.4/45.5 1.76/86.5 1.9/113.3 1.9/105.2

60.7 1.7/93.7 1.88/107.5 2.2/173.8 2.2/175

87.1 1.9/119.9 2.26/207.2 2.3/217.3 2.4/242

114.5 2.4/254.7 3/497 2.37/259.9 3.3/730.8

Table A.30 Stiffness data for molecular weight of 1.4 x 105g/mole cationic chitosan treated fabrics Bending length (cm) / Flexural rigidity (mg x cm)

CC treatment > pad batch concentration Resin treatment: 1.5/39.04

COO- content

(mmol/100g)

0%(Blank) 1% 3%

6%

6.2 1.2/21.4 1.62/48 1.67/51.8 1.63/49.6

30.2 1.4/45.5 1.57/62.1 1.54/57.8 1.47/51.5

60.7 1.7/93.7 1.4/47.2 1.52/57.9 1.57/65.3

87.1 1.9/119.9 1.5/59.6 1.53/61.2 1.51/63.1

114.5 2.4/254.7 1.7/97.8 1.52/67 1.97/159.5

143

Table A.31 Stiffness data for molecular weight of 6.11x 105g/mole cationic chitosan treated fabrics Bending length (cm) / Flexural rigidity (mg x cm)

CC treatment > pad batch concentration Resin treatment: 1.5/39.04

COO- content

(mmol/100g)

0%(Blank) 1% 3%

6%

6.2 1.2/21.4 1.63/49.7 1.68/54.3 1.69/57.3

30.2 1.4/45.5 1.72/79.7 1.83/103.1 1.56/57.4

60.7 1.7/93.7 1.82/97.2 1.71/81.1 1.75/87.8

87.1 1.9/119.9 1.91/113.7 1.68/78.7 1.76/92.1

114.5 2.4/254.7 2/144.5 2.38/243 2.1/171.3

Table A.32 Stiffness data for cationic glycerin treated fabrics Bending length (cm) / Flexural rigidity (mg x cm)

Cationic glycerin treatment > pad batch concentration Resin treatment: 1.5/39.04

COO- content

(mmol/100g)

0% (Blank) 1% 3%

6%

6.2 1.2/21.4 1.63/45.1 1.65/51 1.64/53.5

30.2 1.4/45.5 1.72/76.9 1.8/97.4 1.57/57.8

60.7 1.7/93.7 1.8/91.9 1.71/82 1.77/89.2

87.1 1.9/119.9 1.89/109.5 1.68/79.1 1.79/97.3

114.5 2.4/254.7 2/145.5 2.1/164.5 2.1/165.8

144

Table A.33 Stiffness data for calcium chloride and magnesium chloride treated fabrics Bending length (cm) / Flexural rigidity (mg x cm)

Calcium and Magnesium chloride treatment > pad batch concentration Resin treatment: 1.5/39.04

COO- content

(mmol/100g)

0% (Blank) 0.5M Calcium

Chloride

0.5M Magnesium

Chloride

6.2 1.2/21.4 1.98/88.2 2.0/91.4

30.2 1.4/45.5 1.93/108.5 1.76/81.0

60.7 1.7/93.7 1.82/90.8 187/99.2

87.1 1.9/119.9 2.1/148.1 1.91/113.7

114.5 2.4/254.7 2.3/198.8 2.4/240.5

Table A.34 Stiffness data for PCA treated fabrics Bending length (cm) / Flexural rigidity (mg x cm)

Polycarboxylic acids treatment > pad batch concentration Resin treatment: 1.5/39.04

%N fixed 0%(Blank) 1% 3%

6%

0.24 1.2/21.4 1.66/52.1 1.7/55.9 1.75/58.5

0.45 1.35/33.7 1.25/22.5 1.3/25.8 1.28/24.4

0.73 1.777.4 1.31/28.3 1.34/29.9 1.35/31.3

1.15 1.87/114.1 1.43/48.4 1.49/54.7 1.41/47.4

1.54 2.35/241.4 1.4/49.1 1.51/61.3 1.61/43.6

145

Table A.35 Stiffness data for BTCA treated fabrics Bending length (cm) / Flexural rigidity (mg x cm)

BTCA treatment > pad batch concentration Resin treatment: 1.5/39.04

%N fixed 0%(Blank) 1% 3%

6%

0.24 1.2/21.4 1.66/52.1 1.69/54.9 1.65/49

0.45 1.35/33.7 1.27/22.9 1.35/28.6 1.32/26.7

0.73 1.777.4 1.33/29.9 1.35/30.9 1.35/31.3

1.15 1.87/114.1 1.43/48.4 1.49/55.2 1.45/51.6

1.54 2.35/241.4 1.4/48.6 1.5/59.5 1.6/71.6

8.5 Nitrogen analysis

The %Nitrogen content of the untreated and polycation treated fabrics and their

relationships with ionic content of the fabrics and polyelectrolyte concentration are given

in the tables below.

146

Table A.36 Nitrogen analysis data for molecular weight of 3.2 x 104g/mole cationic chitosan treated fabrics (%Nitrogen)

Cationic chitosan treatment > pad batch concentration COO- content

(mmol/100g)

0% (Blank) 1% 3%

6%

6.2 0.24 0.3 0.31 0.34

30.2 0.25 0.25 0.29 0.3

60.7 0.25 0.32 0.34 0.36

87.1 0.25 0.32 0.41 0.48

114.5 0.26 0.47 0.56 0.67

Table A.37 Nitrogen analysis data for molecular weight of 1.4 x 105g/mole cationic chitosan treated fabrics (%Nitrogen)

Cationic chitosan treatment > pad batch concentration COO- content

(mmol/100g)

0% (Blank) 1% 3%

6%

6.2 0.24 0.24 0.24 0.25

30.2 0.25 0.26 0.28 0.27

60.7 0.25 0.27 0.30 0.3

87.1 0.25 0.30 0.32 0.42

114.5 0.26 0.38 0.47 0.54

147

Table A.38 Nitrogen analysis data for molecular weight of 6.11 x 104g/mole cationic chitosan treated fabrics (%Nitrogen)

Cationic chitosan treatment > pad batch concentration COO- content

(mmol/100g)

0% (Blank) 1% 3%

6%

6.2 0.24 0.27 0.26 0.3

30.2 0.25 0.27 0.34 0.28

60.7 0.25 0.3 0.33 0.36

87.1 0.25 0.29 0.42 0.43

114.5 0.26 0.36 0.53 0.57

Table A.39 Nitrogen analysis data for cationic glycerin treated fabrics (%Nitrogen)

Cationic glycerin treatment > pad batch concentration COO- content

(mmol/100g)

0% (Blank) 1% 3%

6%

6.2 0.24 0.25 0.25 0.28

30.2 0.25 0.26 0.29 0.27

60.7 0.27 0.25 0.31 0.33

87.1 0.25 0.34 0.34 0.36

114.5 0.26 0.37 0.44 0.39