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Magistrsko delo

CROSSLINKING OF CELLULOSE TEXTILE SUBSTRATES

USING UNSATURATED CARBOXYLIC ACIDS

ZAMREŽENJE CELULOZNIH TEKSTILNIH SUBSTRATOV Z

NENASIČENIMI KARBOKSILNIMI KISLINAMI

Marec, 2009 Avtor: Vera VIVOD

Mentor: izr. prof. dr. Bojana VONČINA

Somentor: Prof. Charles Q. YANG

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Vložen original sklepa o potrjeni

temi podiplomskega dela

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Vložen original sklepa o

imenovanju komisije za

oceno podiplomskega dela

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I Z J A V A

Podpisani Vera VIVOD izjavljam, da:

je bilo predloţeno magistrsko delo opravljeno samostojno pod mentorstvom izr. prof. dr.

Bojane VONČINA in somentorstvom Prof. Charles-a Q. YANG;

predloţeno delo v celoti ali v delih ni bilo predloţeno za pridobitev kakršnekoli

izobrazbe na drugi fakulteti ali univerzi;

soglašam z javno dostopnostjo dela Knjiţnici tehniških fakultet Univerze v Mariboru.

Maribor, 10.3.2009 Podpis: ___________________________

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ZAHVALA

Zahvaljujem se mentorici izr. prof. dr. Bojana VONČINA

in somentorju red. prof. dr. Charles Q. YANG za pomoč

in vodenje pri opravljanju podiplomskega dela.

Posebna zahvala velja Petru, Davidu in Vidi ter mojim

staršem.

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CROSSLINKING OF CELLULOSE TEXTILE SUBSTRATES USING

UNSATURATED CARBOXYLIC ACIDS

Key words: crosslinking, unsaturated carboxylic acids, cellulose, FT-Raman spectroscopy, FT-

IR spectroscopy

UDK: 677.21.027.62:547.857.8

ABSTRACT

In this research was studied the use of an unsaturated bifunctional acid (maleic acid) and a

phosphorus-containing inorganic compound (sodium hydroxyphosphinite) to obtain additional

functionality of cotton fabric. First reaction mechanism of maleic acid (MA) and sodium

hydroxyphosphinite (SHP) was investigated in solid state at elevated temperature; further the

crosslinking of MA and additional reaction of SHP on double bond of MA linked to cotton was

studied

Chemical reactions between MA and SHP where investigated by using of FT-Raman and ATR

FT-IR spectroscopy. The influence of time, temperature and molar ratio of MA and SHP of

prepared mixtures in solid state on the reaction mechanism was investigated.

MA/SHP system has potential flame retardant and durable press functions when applied to

cotton cellulose. The esterification mechanism of MA to hydroxyl groups of cellulose and

addition of SHP to C=C was investigated by ATR FT-IR and FT-Raman spectroscopy. The

phosphorus content on treated cotton fabrics was measured by ICP atomic emission

spectroscopy. The final results of MA/SHP system crosslinked to hydroxyl groups of cellulose

was evaluated by WRA. It was shown that MA/SHP system could be used as potential flame

retardant system because it contains phosphor; at the same time in such way treated textile

material has durable press finishing properties.

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ZAMREŽENJE CELULOZNIH TEKSTILNIH SUBSTRATOV Z

NENASIČENIMI KARBOKSILNIMI KISLINAMI

Ključne besede: zamreţenje, nenasičene karboksilne kisline, celuloza, FT-Raman

spektroskopija, FT-IR spektroskopija

UDK: 677.21.027.62:547.857.8

POVZETEK

V magistrski nalogi smo proučevali uporabo mešanice nenasičene bifunkcionalne karboksilne

kisline (maleinska kislina) in natrijevega hidrogen fosfata I kot reagenta za doseganje

polifunkcionalnosti bombažnega substrata. Preiskovali smo kemijske reakcije med maleinsko

kislino (MA) in natrijevim hidrogen fosfatom I (SHP) v trdnem stanju pri povišani temperaturi,

nadalje smo proučevali proces zamreženja MA in adicije SHP na dvojno C=C vez MA, ki je

vezana na bombaž.

Potek kemijskih reakcij mešanic MA in SHP v trdnem stanju smo proučevali z FT-Raman in ATR

FT-IR spektroskopijo. Pri tem smo raziskali vliv temperature in časa segrevanja in molarnih

razmerij med obema komponentama mešanice na mehanizem reakcije.

Bombažni substrat smo obdelali z obdelovalnimi kopelmi, ki so vsebovale MA/SHP. Proučevali

smo vpliv molarnih razmerij med obema komponentama v obdelovalni kopeli na učinkovitost

apreture. Z MA/SHP sistemom obdelan celulozni tekstilni material je lahko potencialeno

ognjevaren in ima istočasno vrhunske lastnosti (nemečkljivost, dimenzijska stabilnost).

Mehanizem estrenja MA na hidroksilne skupine celuloze in adicija SHP na C=C dvojno vez

maleinske kisline smo proučevali z ATR-FT IR in Raman spektroskopijo. Vsebnost fosforja na

obdelanem tekstilnem substratu smo določili z ICP atomsko emisijsko spektroskopijo. Končni

rezultat zamreženja hidroksilnih skupin celuloze z MA/SHP sistemom smo ovrednotili z

merjenjem kotov razgubanja. Ugotovili smo, da lahko sistem MA/SHP uporabimo kot potencialni

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ognjevarni reagent, saj vsebuje fosfor in istočasno lahko tako obdelanemu materialu izboljšamo

nemečkljivost.

Iz rezultatov raziskovalnega dela lahko zaključimo, da poteka zamreženje bombažnega

celuloznega substrata tako, da se natrijev hidrogen fosfat I adicijsko veže na dvojni C=C vezi

maleinskih kislin, ki so vezane na hidroksilne skupine celuloze preko esternih vezi, pri čemer

pride do premreženja.

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TABLE OF CONTENTS

1 INTRODUCTION 1

2 CELULLOSE FIBERS 3

2.1 Molecular Structure of Cellulose 3

2.2 Supermolecular structure 5

2.3 The Chemical Reactivity of Cellulose Fibres 6

2.3.1 Esterification of cellulose fibres 14 7

2.4 Crosslinking of cellulose 8

2.4.1 General 8

2.4.2 Development of different crosslinking agents 8

2.4.2.1 Use of Maleic acid (MA) as crosslinking agent 9

2.5 Heat and flame protection of fabrics 1 9

2.5.1 Mechanisms of flame retardancy 34 10

2.5.2 Flame retardant chemistry 12

2.5.3 Thermal degradation of cellulose 13

2.5.4 Non-durable flame retardants 34 15

2.5.5 Durable flame retardants for cellulose 15

2.5.6 Carboxylic acids as flame retardant finishes 17

2.5.7 Flame-retardant test methods 18

3 ANALYTICAL METHODS 20

3.1 Introduction 20

3.2 Raman spectroscopy 20

3.2.1 Basic theory 46 20

3.3 Infrared (IR) spectroscopy 23

3.3.1 The theoretical principles of FT- IR 23

3.3.2 Attenuated total reflectance Fourier transform spectroscopy (ATR FT-IR Spectroscopy) 24

3.4 Comparison between IR an Raman spectroscopy- Molecular vibrations 46 26

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3.5 Atomic spectroscopy 28

3.5.1 Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) 56 28

4 EXPERIMENTAL 30

4.1 Materials 31

4.2 Chemicals 31

4.3 Analytical Methods 32

4.3.1 Raman Spectroscopy 32

4.3.2 ATR-FT IR Spectroscopy 32

4.3.3 ICP Atomic Emission spectroscopy 32

4.4 Experiments 32

4.4.1 Preliminary studies of MA/SHP mixtures 32

4.4.2 Treatments of cellulose fabrics with maleic acid with addition of SHP or DSHP 34

4.4.3 Preparation of samples for determination of phosphorus fixation by ICP AES 36

4.4.4 Wrinkle Recovery Angle (WRA) according to DIN 53 890 standard 37

5 RESULTS AND DISCUSSION 38

5.1 Preliminary studies of MA/SHP mixtures 38

5.2 FT-Raman analysis 38

5.2.1 The influence of temperature of heating 41

5.2.2 The influence of time of heating 47

5.2.3 Heating of MA at 150 ºC for different times without adding a catalyst 49

5.2.4 The influence of molar ratio of MA and SHP 52

5.2.5 Addition of Na2HPO3 56

5.3 FT-IR analysis 59

5.3.1 The influence of temperature of heating 62

5.3.2 The influence of time of heating 65

5.3.3 Heating of MA at 150 ºC for different times without adding a catalyst 66

5.3.4 The influence of molar ratio of MA and SHP 67

5.3.5 Addition of Na2HPO3 69

5.4 Treatment of cellulose fabrics with maleic acid 71

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5.4.1 Treatment of cellulose fabrics with maleic (MA) acid with addition of SHP or DSHP catalyst 71

5.4.1.1 FT-IR analysis 71

5.4.1.2 FT-Raman analysis 74

5.4.1.3 Wrinkle recovery angle (WRA) 75

5.4.2 Determination of crosslinking efficiency by ICP- AES 76

6 CONCLUSIONS 77

7 REFERENCES 80

8 BIBLIOGRAPHY 85

9 CURRICULUM VITAE 88

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LIST OF FIGURES

Figure 2.1: Molecular structure of cellulose. ................................................................................. 3

Figure 2.2: Intra- and intermolecular hydrogen bonds of cellulose 9 . ......................................... 4

Figure 2.3: Cellulose-I unit cell structure of native cellulose according to Meyer, Mark and

Misch 5 . ......................................................................................................................................... 5

Figure 2.4: Microfibrillar model of a cellulose fibre structure (A – crystalline area, B –

amorphous area, C – interfibrillar molecules, D – crystalline block, E – pores 10 . .................... 6

Figure 2.5: Combustion cycle for fibres 35 . ................................................................................. 10

Figure 2.6: Endothermic decomposition reactions. ....................................................................... 11

Figure 2.7: Formation of foamed glass. ........................................................................................ 11

Figure 2.8: Crosslinking with phosphoric acid. ............................................................................ 12

Figure 2.9: Competing free radical reactions during combustion of halogen (X)-containing

material (M). R is the organic residue. .......................................................................................... 12

Figure 2.10: Gas phase free radical reactions with antimony. ..................................................... 13

Figure 2.11: Pyrolysis and combustion of cellulose 37, 38 ......................................................... 14

Figure 2.12: Thermal degradation of cellulose. ............................................................................ 14

Figure 2.13: Thermal decomposition of ammonium salts.............................................................. 15

Figure 2.14: THPC-urea-ammonia reaction (Proban process). ................................................... 16

Figure 2.15: Reaction between N-methyol dimethylphosphonopropionamide and cellulose. ....... 17

Figure 2.16: Binding of a hydroxy-functional organophosphorus oligomer to cellulose by BTCA.

........................................................................................................................................................ 18

Figure 3.1: Diagram of the Raylight and Raman scattering processes. ........................................ 21

Figure 3.2: NIR FT instrument schematic 47 . ............................................................................. 22

Figure 3.3: Single bounce ATR 52 . ............................................................................................. 25

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Figure 3.4: Spring and ball model – three modes of vibration for H2O and CO2 ......................... 26

Figure 3.5: Electron cloud model of carbon dioxide showing an IR and Raman active vibrations

........................................................................................................................................................ 27

Figure 3.6: Steps involved in the analysis of aqueous samples by ICP-AES. ................................ 29

Figure 5.1: Raman spectrum of maleic acid (MA). ........................................................................ 38

Figure 5.2: Raman spectrum of Maleic anhydride (MAnh). .......................................................... 39

Figure 5.3: Raman spectrum of sodium hydroxyphosphinite (SHP). ............................................ 40

Figure 5.4: Raman spectrum of disodium hydrogen phosphite (DSHP). ...................................... 40

Figure 5.5: Raman spectra of MA, SHP and a mixture of MA/SHP (molar ratio 1:1) at room

temperature. ................................................................................................................................... 41

Figure 5.6: Raman spectra of MA/SHP mixtures (molar ratio 1:1) at room temperature at

different times; ................................................................................................................................ 43

Figure 5.7: Raman spectra of MA/SHP mixtures (1:1 molar ratio) heated at temperatures from

120 to 160 °C for 2 minutes. .......................................................................................................... 44

Figure 5.8: Raman spectra of MA/SHP mixtures (1:1 molar ratio), spectrum of mixture at

ambient temperature (sample S1) and mixtures heated at elevated temperatures (samples S12-

S15) for 3 minutes. ......................................................................................................................... 46

Figure 5.9: Raman spectra of MA/SHP mixtures (Samples S7, S12, S14 and S15, Table 4.1) in the

range from 3316 till 1924 cm-1

: ..................................................................................................... 47

Figure 5.10: Raman spectra of MA/SHP mixtures (1:1 molar ratio) heated at T= 150 °C for

different times (samples: S16-S20, Table 4.1). ............................................................................... 48

Figure 5.11: Raman spectra of MA and MAnh at ambient temperature and MA heated at 150 ºC

for different times. .......................................................................................................................... 50

Figure 5.12: Raman spectra of MA (a)) and maleic anhydride (b)) at ambient temperature and

MA heated at T= 150 ºC for 6 minutes(c)) and in region from 3253 till 2999 cm-1

. ..................... 51

Figure 5.13: Raman spectra of MA (a)) and MAnh (b)) at ambient temperature and of MA heated

at T= 150 ºC for 6 minutes (c)) in region from 1891 till 1815 cm-1

. .............................................. 52

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Figure 5.14: Raman spectra of MA/SHP mixtures in different molar ratio heated at T= 150 °C

for 4 min. ........................................................................................................................................ 53

Figure 5.15: Raman spectra of MA/SHP mixtures in different molar ratio heated at 150 °C for 5

min. ................................................................................................................................................. 54

Figure 5.16: Raman spectra of MA/SHP mixtures in different molar ratio heated at T= 150 °C,

tcuring = 3 min. ................................................................................................................................. 55

Figure 5.17: Formation of maleic anhydride at elevated temperature. ......................................... 56

Figure 5.18: Addition of SHP on double C=C bond of MA at elevated temperature. ................... 56

Figure 5.19: Disodium hydrogen phosphite (DSHP). .................................................................... 56

Figure 5.20: Raman spectra of MA/DSHP mixtures in different molar ratio heated at T= 150 °C

for 4 min. ........................................................................................................................................ 57


for 5 min. ........................................................................................................................................ 58


for 3 min. ........................................................................................................................................ 58

Figure 5.23: FT-IR Spectrum of maleic acid (MA). ....................................................................... 59

Figure 5.24: FT-IR Spectrum of maleic anhydride (MAnh). ......................................................... 60

Figure 5.25: FT-IR Spectrum of sodium hydroxyphosphinite (SHP). ............................................ 60

Figure 5.26: FT-IR Spectrum of disodium hydrate phosphite (DSHP). ........................................ 61

Figure 5.27: FT-IR spectra of MA/SHP mixture (1:1 molar ratio), MA and SHP at ambient

temperature. ................................................................................................................................... 62

Figure 5.28: FT-IR Spectra of MA/SHP mixtures (1:1 molar ratio) heated at different

temperatures; a) T= 120 ºC, b) T= 140 ºC, c) T= 160 ºC for 2 minutes. ...................................... 63


temperatures (a) T= 140 ºC, b) T= 150 ºC, c) T= 160 ºC) for 3 minutes. ..................................... 64

Figure 5.30: FT IR Spectra of MA/SHP mixtures (1:1 molar ratio) heated at 150 ºC for different

times (t= 0.5, 1, 2, 4 and 6 minutes)............................................................................................... 65

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Figure 5.31: FT-IR spectra of MA, MAnh at ambient temperature and MA heated at 150 ºC for 8

minutes. .......................................................................................................................................... 66

Figure 5.32: FT-IR spectra of MA/SHP mixtures in different molar ratio heated at 150 °C, for 4

min in region from 1936 to 1347 cm-1

. ........................................................................................... 67

Figure 5.33: FT-IR spectra of MA/SHP mixtures in different molar ratio heated at T= 150 °C, t =

4 min in region from 2062 to 1390 cm-1

. ........................................................................................ 68



. ........................................................................................ 69

Figure 5.35: FT-IR spectra of MA/DSHP mixtures in different molar ratio heated at 150 °C for 4

min. ................................................................................................................................................. 70

Figure 5.36: FT-IR spectra of sample S54 in the range from 1788 to 1522 cm-1

: ........................ 72

Figure 5.37: Conversion of carboxylic acid groups into carboxylate anions. .............................. 73

Figure 5.38: The ester carbonyl bond intensities’ of treated cotton fabrics with solutions of

MA/SHP (samples: S51-S55) or MA/DSHP (samples: S56-S60). .................................................. 73

Figure 5.39: Raman spectra of untreated cotton fabric marked as a) and spectrum of the treated

cotton sample S54 marked as b). .................................................................................................... 74

Figure 5.40: Conditioned WRA of cotton fabrics treated by solutions of MA/SHP (samples: S51-

S55) and MA/DSHP (samples: S56-S60) in different mole ratios, cured at 165 ºC for 3 min and

rinsed, versus catalysts moles in treating baths. ............................................................................ 75

Figure 5.41: The phosphorus concentration of the cotton fabric treated with MA/SHP at different

mole ratios and cured at 170 °C (after 1 home laundering) versus SHP moles in treating baths. 76

Figure 6.1: Reaction scheme. ......................................................................................................... 78

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LIST OF TABLES

Table 2.1: Common flammability test methods. ............................................................................. 19

Table 3.1: Common crystal materials used in ATR IR spectroscopy 53 . .................................... 25

Table 4.1: Treatment characteristics of samples (MA, and mixtures MA/SHP). ........................... 33

Table 4.2: Treatment characteristics of samples (MA/DSHP mixtures). ....................................... 34

Table 4.3: The concentrations of MA and SHP used for the treatment of the cotton fabrics. ....... 35

Table 4.4: The concentrations of MA and DSHP used for the treatment of the cotton fabrics. .... 35

Table 4.5: The concentrations of SHP and MA used for the treatments of the cotton fabrics. ...... 36

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SYMBOLS AND ABBREVIATIONS

T °C temperature

TP °C temperature of pyrolis

TC °C temperature of combustion

t min time

n ground vibrational state

m higher energy exited vibrational state

DP The degree of polymerization

DMDHEU dimethylol dihydroxyethylene urea

WHO World health organization

MA maleic acid

BTCA 1,2,3,4 butanetetracarboxylic acid

HDTST 2-hydroxy-4,6-di-thiosuccinyl-s-triazine

THPC tetrakis(hydroxymethyl)phosphonium chloride

TEA triethanolamine

LOI The limiting oxygen index

NIR Near infrared

FT-IR Fourier Transform infrared spectroscopy

AAS Atomic absorption spectroscopy,

AES Atomic emission spectroscopy

AFS Atomic fluorescence spectroscopy

ICP-AES Inductively coupled plasma atomic emission spectroscopy

SHP sodium hydroxyphosphinite

MAnh maleic anhydride

DSHP disodium hydrate phosphite

WRA Wrinkle recovery angle

Crosslinking of cellulose textile substrates with unsaturated carboxylic acids Master thesis

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1 INTRODUCTION

With industrialization, the safety of human beings has become an important issue. A growing

segment of industrial textile industry has therefore been involved in a number of new

developments in fibres, fabrics and protective clothing. Major challenges to coatings and

fabrication technology producing the flame-retardant textile industry have been to produce

environmentally friendly, non-toxic flame-retardant systems that complement the comfort

properties of textiles 1 .

Cotton is one of the most flammable fibers. Durable flame retardants commonly used for cotton

include those based on tetrakis(hydroxymethyl)phosphonium (THPX) (Proban process), and N-

methylol dimethylphosphonopropionamide known as Pyrovatex process. However, those

traditional flame retardants are not suitable for applications to all textile substrates.

Multifunctional carboxylic acids have been used as non-formaldehyde durable press finishing

agents for cotton since the late 1980s 2 . Blanchard and Graves investigated the application of

polycarboxylic acids to reduce the flammability of cotton and cotton/polyester carpets 3 .

Phosphorus-containing maleic acid (MA) oligomer was also used to reduce the flammability of

cotton/polyester fleece 4 .

In this research, we will investigate the use of the combination of an unsaturated bifunctional acid

(maleic acid) and a phosphorus-containing inorganic compound sodium hydroxyphosphinite to

reduce the flammability of cotton fabric and the chemical reactions of maleic acid (MA) and

sodium hydroxyphosphinite (SHP) on cotton. At the same time MA/SHP treated cotton fabrics

will be durable press finished.

First investigation of reactions of MA with SHP will be made, where mixtures of MA and

catalyst SHP will be prepared. In such way the influence of time, temperature and molar ratio on

the reaction mechanism will be studied by using of FT-Raman and FT-IR spectroscopy.


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Second we will introduce MA/SHP as a flame retardant finishing system for cotton cellulose: by

studying of esterification mechanism between MA and cotton cellulose, the crosslinking of

cotton cellulose, and the use of the combination of MA and SHP as a flame retardant finishing

system for cotton fleece. The efficiency of crosslinking will be determined by Wrinkle Recovery

Angle measurements, FT-IR and FT-Raman spectroscopy and by ICP atomic emission

spectroscopy.


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2 CELULLOSE FIBERS

Cotton is the purest natural source of cellulose. The cellulose content of raw cotton fibers ranges

from 88 to 96% depending on the soil, climate, variety of cotton and other factors which

prematurely interrupt its growth 5 .

2.1 Molecular Structure of Cellulose

Cellulose is an organic polymer containing 1:4 – β – D glucopyranose units linked by β–1,4-

glucosidic bonds. The cellulose chain is a long linear molecule containing at least 3000 1:4 – β –

D glucopyranose units organized in a chain with the following structure 5 :

O

1

CH2OH

O

OH

OH

H

OH

H

H

H

H

OCH

2OH

OH

OOHO

4

OHOH

CH2OH

H

H

H

H

H H

H

H

H

OHH

n-2

Figure 2.1: Molecular structure of cellulose.

Cellulose contains one primary hydroxyl group and two secondary hydroxyl groups per 1: 4 – β –

D glucopyranose unit.

Terminal hydroxyl groups are presented at both ends of cellulose chain molecule. However, these

groups are quite different in nature. The C1 hydroxyl at the one end of molecule is an aldehyde

hydrate group with reducing activity and originated from formation of the pyranose ring trough

an intramolecular hemiacteal reaction. In the contrast with this, the C4 hydroxyl on the other end

of chain is an alcoholic hydroxyl and as such nonreducing.

The chemical character of the cellulose molecule is determined by the sensitivity of the -

glucosidic linkages between the glucose repeating units to hydrolytic attack and by the presence


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of three reactive hydroxyl groups, one primary and two secondary, in each of the base units.

These reactive hydroxyl groups are able to undergo etherification and esterification reactions 1 .

With X- ray analysis it is hard to define the structure of cellulose. More detailed information on

the structure has been obtained by infrared spectroscopy and electron diffraction. The latest

picture of the unit cell is a hydrogen bonded network in which the cellulose chains are depicted as

being parallel and antiparallel 6 . Three different types of hydrogen bond exist in the cellulose

chain. The first one is between C6 hydroxyls of antiparallel chains and glycosidic ether oxygen of

parallel chains, the second one is between C6 hydroxyls of parallel chains and glycosidic ether

oxygen of the antiparallel and the third is between C6 and C2 hydroxyls on an adjacent chains.

There is also an intramolecular hydrogen bond between the C3 hydroxyls and the ring oxygens

of the adjacent anhydroglucose units of the same chain 7, 8 .

Figure 2.2: Intra- and intermolecular hydrogen bonds of cellulose 9 .

The formation of strong intra-molecular hydrogen bonds shown in figure 2.2 produces the natural

stiffness and straightness of the cellulose chains. Because of inter-molecular hydrogen bonding

and its regular structure, cellulose exists in a state of high crystallinity. The relative amount of

crystallinity ranges from 50 to 99 percent for the native cellulose. The size of the crystalline areas

has been estimated to be about 6 to 10 nm in diameter and 60 to 150 nm in length.

The degree of polymerization (DP) of cellulose varies for different types of cellulose. The

average value for unpurified native cellulose may well exceed 10,000, but purification involving

treatment with alkali reduces this value to about 1000 to 2000.


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Cellulose exists in at least 5 polymorphic forms, but only cellulose I and II are important from the

textile point of view. Cellulose I is the form normally found in the native cellulose of plants,

whereas cellulose II occurs in regenerated materials and when native materials are treated with

strong swelling agents 5 .

Figure 2.3: Cellulose-I unit cell structure of native cellulose according to Meyer, Mark and

Misch 5 .

2.2 Supermolecular structure

The smallest morphological unit of cellulose fibre is micro-fibril, which consists of 36 parallel

cellulose molecules linked with hydrogen bonds. Fibrils are made up of crystalline and

amorphous areas which alternate along its length (Figure 2.4). In the micro-fibril those areas are

connected due interfibrillar molecules which lead from one crystalline area through the

amorphous area into another crystalline area 5 .


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Figure 2.4: Microfibrillar model of a cellulose fibre structure (A – crystalline area, B –

amorphous area, C – interfibrillar molecules, D – crystalline block, E – pores 10 .

2.3 The Chemical Reactivity of Cellulose Fibres

The crucial factors to achieve specific physical properties of cellulose are the relative reactivities

of C2, C3 and C6 hydroxyl groups towards various types of reagents and the relative availabilities

of these groups 11 . As a consequence of differences in the reactivity and accessibility of the

three hydroxyl groups in the chain units, their overall reactivity decreases in the order C6 > C2 >

C3 8, 9 . In most chemical reactions involving cellulose, the fibre structure is swollen in order to

render all portions of the fibre available for the reaction. The amorphous areas swell and react

first, followed by a swelling of the outer layers of the crystallites. By the penetration of the

reagent, the strong hydrogen bonds in cellulose can be broken and prepared for chemical reaction

14 .

Reactions involving cellulose may be divided into two main groups. The first group involves the

degradation of cellulose by acid, alkalis, oxidizing agents, heat, radiation or enzymes. Even slight

degradation may affect the physical properties of cellulose profoundly. Complete degradation

convert cellulose into carbon dioxide and water. In intermediate stages carbonyl and carboxyl

groups are formed.


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For industrial use reactions involving esterification and etherification of hydroxyl groups in

cellulose, are important. In both reactions covalent bonds between the fibre and reactant are

formed 14 .

2.3.1 Esterification of cellulose fibres 14

Cellulose can be esterified with most inorganic and organic acids. The formation of esters from

cellulose is analogous to the esterification of simple alcohols. Cellulose reacts more readily with

etherifying agents if a swelling agent such as a strong solution of sodium hydroxide is present.

The alkaline cellulose then reacts with compounds such as alkyl halides, ethylene chlorhydrin

and ethylene oxide to form cellulose ethers

As in low molecular alcohols the three hydroxyl groups in each cellulose unit of the cellulose

chain molecules are able to react with inorganic and organic acids or their anhydrides and

chlorides to form esters. The mechanism of the ester formation reaction depends on the type of

reactants is used:

1. General esterification mechanism (formation of an oxonium ion; inorganic acid

esterification): In the reaction with inorganic acids the polar OH-groups are displaced by

nucleophilic groups or compounds in a strong acid environment. The formation of an

oxonium ion is the firs step in this nucleophilic substitution.

2. The reaction with organic acid proceeds as a nucleophilic addition. The addition of the

organic acid to the alcohol groups can be promoted by acid catalysis. Under such conditions a

proton is first added to the electron-negative oxygen of the carboxylic group. The organic

acid thus positively polarized is now fit to interact with the nucleophlilic alcohol groups.

3. Cellulose esters can be prepared by interactions with acid anhydrides or halides in the

presence of the basics, rather than acids catalysis 5 .


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2.4 Crosslinking of cellulose

2.4.1 General

The primary purpose of cellulose fiber crosslinking in cotton fabrics is to obtain good shape

retention on washing. The second aim of the treatment is to improve physical properties of cotton

fabrics such as durable press, crease resistance and laundering durability. Crosslinking agents in

common use are generally water soluble polyfunctional agents capable of reaction with cellulose

under relatively mild acid conditions. In our research we successfully combine improving of

these properties with reducing of flammability of cotton.

2.4.2 Development of different crosslinking agents

In conventional treatments of wrinkle-free fabric, Dimethylol dihydroxyethylene urea

(DMDHEU) reagent is usually used. But this type of reagent is found to have released

formaldehyde which is harmful to human health. It is proven that formaldehyde can cause

allergy, irritations, contact dermatitis, headaches and chronic fatigue, and now is also declared by

World health organization (WHO) as ``carcinogenic to humans´´. Therefore, many countries have

regulated the use of formaldehyde on fabrics. In the US and Japan, the upper limit of

formaldehyde content for apparel is less than 75ppm and according to Öko-tex 100 standard, the

formaldehyde concentration for infant clothes is less than 20ppm. This 20ppm restriction is very

difficult to reach by using ordinary DMDHEU reagent.

In the 1960s, research within the textile industry started to focus on cross-linking of cellulose

with different carboxylic acids 15, 16 . Polycarboxylic acids react with hydroxyl groups of

cellulose at elevated temperature. This research continue in the year 1988 when Welch published

work showing that polycarboxylic acids with weak base catalysts provided the same level of

durable press performance and finishing durability as conventional DMDHEU reactants 17 . To

elucidate the crosslinking mechanism much work has been done 18-25 . The crosslinking of

cellulose with polycarboxylic acids initially involves formation of cyclic anhydride which than

react further with cellulose hydroxyl groups to form ester bonds. If a polycarboxylic acid has

three or more carboxylic acid groups, the formation of such an anhydride can occur more than

once and crosslinking of the cellulose molecules occurs 19, 20 .


- 9 -

2.4.2.1 Use of Maleic acid (MA) as crosslinking agent

The use of maleic acid as durable press finishes is not reported till now. Yang made a research in

which he analyzed cotton fabrics treated with different acids using FT-IR photoacoustic

spectroscopy; maleic acid was one of the acids studied 26 . This research was done in aim to

elucidate the mechanism of esterification between polycarboxylic acid and cotton cellulose by the

infrared spectroscopic data. Yang also used maleic acid in treatments of cotton fabrics together

with polycarboxylic acids such as 1,2,3,4 butanetetracarboxylic acid (BTCA) or together with

BTCA, MA and itaconic acid. Yang and coworkers were very successful in studies of polymaleic

acid as crosslinking agent; polymerization of maleic acid to a poly(maleic) acid and effectiveness

of it as a crosslinking agent for cotton cellulose was studied 27 . Beside polymerization of

maleic acid also some others dicarboxylic acids were successful polymerized such as

poly(itaconic) acid and poly(fumaric) acid. Poly(itaconic) acid was also applied to cotton fabrics

by crosslinking 28- 30 . Kim and coworkers used malic acid as crosslinker in treatments of

cotton fabrics 31 . Lewis and Vončina prepared a 2-hydroxy-4,6-di-thiosuccinyl-s-triazine

(HDTST), product of reaction between mercaptosuccinic acid (dicarboxylic acid) and cyanuric

chloride, the efficiency of HDTST as crosslinker for cotton cellulose was also reported 32, 33 .

2.5 Heat and flame protection of fabrics 1

With industrialization, the safety of human beings has become an important issue. A growing

segment of industrial textile industry has therefore been involved in a number of new

developments in fibres, fabrics and protective clothing. Major challenges to coatings and

fabrication technology producing the flame-retardant textile industry have been to produce

environmentally friendly, non-toxic flame-retardant systems that complement the comfort

properties of textiles.

For heat and flame protection, requirements range from clothing for situations in which the

wearer may be subjected to occasional exposure to a moderate level of radiant heat as part of

his/hers normal working day, to clothing with prolonged protection, where the wearer is

subjected to severe radiant or convective heat, to direct flame, for example the fire fighters suit.

In the process of accomplishing flame protection, however, the garment may be so thermally

isolative and water vapour impermeable that the wearer may begin to suffer discomfort and heat


- 10 -

stress. Attempts have therefore been made to develop thermal and heat protective garments which

can be worn without any discomfort.

2.5.1 Mechanisms of flame retardancy 34

In order to understand the mechanisms of effective flame retardants better, the mechanism of

combustion should first be clarified. Combustion is an exothermic process that requires three

components, heat, oxygen and suitable fuel. When left unchecked, combustion becomes self

catalysing and will continue until the oxygen, the fuel supply or excess heat is depleted. A

diagram of current model of combustion of textiles is given in Fig. 2.5.

When heat is applied, the fibre’s temperature increases until the pyrolysis temperature TP, is

reached. At this temperature, the fibre undergoes irreversible chemical changes, producing non-

flammable gases (carbon dioxide, water vapour and the higher oxides of nitrogen and sulphur),

carbonaceous char, tars (liquid condensates) and flammable gases (carbon monoxide, hydrogen

and many oxidisable organic molecules). As the temperature continues to rise the tars also

pyrolyse producing more nonflammable gases, char and flammable gases. Eventually, the

combustion temperature, TC , is achieved.

Figure 2.5: Combustion cycle for fibres 35 .

At this point, the flammable gases combine with oxygen in the process called combustion, which

is a series of gas phase radical reactions. These reactions are highly exothermic and produce large


- 11 -

amounts of heat and light. The heat generated by the combustion process provides the additional

thermal energy needed to continue the pyrolysis of the fibre, thereby supplying more flammable

gases for combustion and perpetuating the reaction. The burning behaviour of textiles is

determined more by the speed or rate of heat release than by amount of this heat.

Attempts to disrupt this cycle for textile substrates have focused on several approaches. One

method is to provide a heat sink on or in the fibre by use of materials that thermally decompose

through strongly endothermic reactions. If enough heat can be absorbed by these reactions, the

pyrolysis temperature of the fibre is not reached and no combustion takes place. Examples of this

method are the use of aluminium oxide trihydrate and calcium carbonate as fillers in polymer and

coating (Fig. 2.6).

Al2O3 x 3H2O

CaCO3

Al2O3 + 3H2O

CaO + CO2

Figure 2.6: Endothermic decomposition reactions.

Another approach is to apply a material that forms an insulating layer around the fibre at

temperatures below the fibre pyrolysis temperature. Boric acid and its hydrated salts function in

this capacity (Fig. 2.7). When heated, these low melting compounds release water vapour and

produce a foamed glassy surface on the fibre, insulating the fibre from the applied heat and

oxygen.

2 H3BO3

-2 H2O2 H BO2

B2O3

-H2O

Figure 2.7: Formation of foamed glass.

A third way to achieve flame retardancy is influencing the pyrolysis reaction to produce less

flammable volatiles and more residual char. This 'condensed phase' mechanism can be seen in the

action of phosphorous-containing flame retardants which, after having produced phosphoric acid


- 12 -

through thermal decomposition, crosslink with hydroxyl-containing polymers thereby altering the

pyrolysis to yield less flammable by-products (Fig.2.8).

OH

P OHOH

OH

O OH

P OO

OH

O

+ + + 2H2O

Figure 2.8: Crosslinking with phosphoric acid.

The ‘condensed phase’ strategy includes the described mechanism of removal of heat and the

enhancement of the decomposition temperature as in heat resistant fibres.

A fourth approach to preventing combustion is to interfere with the free radical reactions that

provide the heat needed for the process to continue. Materials that act in this ‘gas phase’

mechanism include halogen containing compounds which, during combustion, yield hydrogen

halides that form relatively long lived, less reactive free radicals, effectively reducing the heat

available for perpetuating the combustion cycle, and which decrease the oxygen content by flame

gas dilution (Fig.2.9).

Figure 2.9: Competing free radical reactions during combustion of halogen (X)-containing

material (M). R is the organic residue.

2.5.2 Flame retardant chemistry

The most important commercial flame retardants can be classified into three broad categories

36 . Primary flame retardants based on phosphorus (condensed phase mechanism) and halogens

(gas phase mechanism); synergistic retardancy enhancers that have only small flame retarding


- 13 -

effects by themselves, but greatly enhance the flame retardancy of primary flame retardants

(nitrogen with phosphorous and antimony with halogens); and adjunctive flame retardants that

exhibit their activity through physical effects (borates, alumina trihydrate, calcium carbonate and

intumescents).

Organic nitrogen is thought to help control the pH during the crosslinking reactions of phosphoric

acid. The nitrogen can become protonated, reducing the amount of acid available. If the pH is too

low, cellulose will undergo acid hydrolysis rather than crosslinking. If the pH is too high, the acid

catalysed crosslinking cannot take place. Organic nitrogen may be converted to phosphorous acid

amides that also catalyse the dehydration and carbonisation of cellulose. The synergistic effect of

antimony comes from the volatility of antimony trihalides and the effectiveness of antimony

compounds in scavenging free radicals (Fig. 2.10) over a broad temperature range (for example

245-565 °C).

Figure 2.10: Gas phase free radical reactions with antimony.

2.5.3 Thermal degradation of cellulose

Cellulose can be classified as a polymer of a moderate thermal stability 11 . Figure below shows

the schematic representation of cellulose pyrolysis and combustion.


- 14 -

Figure 2.11: Pyrolysis and combustion of cellulose 37, 38

One important thermal degradation mechanism of cellulose fibres (cotton, rayon, linen, etc.) is

the formation of the small depolymerisation product levoglucosan (Fig. 2.12). Levoglucosan and

its volatile pyrolysis products are extremely flammable materials and are the main contributors to

cellulose combustion 34 .

O

O

O

O

CH2OH

CH2OH

OH OH

OH

OH

O

O

OH

OH

O

CH2

OH

Levoglucosan

350 oC

Figure 2.12: Thermal degradation of cellulose.

Compounds that are able to hinder levoglucosan formation are expected to function as flame

retardants for cellulose. The crosslinking and the single type of esterification of cellulose polymer

chains by phosphoric acid reduces levoglucosan generation, catalyses dehydration and

carbonisation, and thus functions as an effective flameretardant mechanism.

Precursors that can yield phosphoric acid during the early stages of fibre pyrolysis form the

majority of successful flame retardants for cellulose. However, it is not sufficient to supply just

phosphoric acid precursors. The presence of nitrogen has been found to provide a synergistic

effect with phosphorous. Minimum levels of added phosphorous and nitrogen for effective flame

retardancy have been estimated at ~2 % P and ~1% N. However, these minimum levels can vary

greatly depending on fabric construction and test requirements.


- 15 -

2.5.4 Non-durable flame retardants 34

Inorganic salts have long been known to provide flame retardancy on cellulose material that will

not be exposed to water, rain or perspiration. The French chemist Gay-Lussac proposed a borax

and ammonium sulphate treatment as a flame retardant for cotton in 1820. Today, a mixture of

boric acid and borax is still an effective flame retardant for cotton at ~10 % solids add-on.

Ammonium salts of strong acids, especially phosphoric acid (P/N synergism) are particularly

useful as nondurable flame retardants for cellulose. Three commercially important products are

diammonium phosphate, ammonium sulfamate and ammonium bromide. These salts readily form

the corresponding strong acids upon heating (Fig. 2.13).

(NH4)2HPO

4 P OHOH

OH

O

S

O

O

NH2

O NH4

OH2

S

O

O

OH OH

2 NH3 +

++

NH4Br NH3

2 NH3

+ HBr

Diammonium phosphate

Ammonium sulfamate

Ammonium bromide

Figure 2.13: Thermal decomposition of ammonium salts.

Diammonium phosphate and ammonium sulfamate are used at ~15 % solids add-on and function

as condensed phase flame retardants, not only by crosslinking but also by dehydrating cellulose

to polymeric char with reduced formation of flammable by-products. The water insoluble

ammonium polyphosphate is an effective flame retardant and is added to coatings and binder

systems, for example for pigment printing. Ammonium bromide is applied at ~10 % solids add-

on and is effective in the gas phase.

2.5.5 Durable flame retardants for cellulose

Although inorganic salts can provide excellent flame-retardant properties for cellulose,

reasonable laundering durability must be incorporated into any finish destined for apparel use.

The most successful durable flame retardants for cellulose are based on phosphorous- and


- 16 -

nitrogen-containing chemical systems that can react with the fibre or form crosslinked structures

on the fibre. The key ingredient of one of these finishes is tetrakis(hydroxymethyl)phosphonium

chloride (THPC), made from phosphine, formaldehyde and hydrochloric acid 36 .

A Proban process of the THPC-urea system was developed to produce finishes with less stiffness

and fibre damage. A precondensate is prepared by the careful reaction of THPC with urea. This

precondensate is padded onto the fabric and the fabric is dried to specific moisture content (~ 15

%). The fabric is then exposed to ammonia vapours in a special reaction chamber, followed by

oxidation with hydrogen peroxide (Fig. 2.14). The polymer that forms is primarily located in the

lumen of the cotton fibre. The final finish provides durable flame retardancy to cotton with much

improved fabric properties.

P+

CH2OHHOCH

2

CH2OH

CH2OH

Cl

H2NCONH

2

P+

CH2NHCONHHOCH

2

CH2OH

CH2OH

P+

CH2OHCH

2

CH2OH

CH2OH

Cl Cl

P CH2NHCONH PCH

2CH2

CH2

P CH2NHCONH PCH

2CH2

CH2

CH2

CH2

NH

CH2

NH

CH2

NHNH

NH NH

P

O

CH2

CH2

CH2

+

THPC Urea

NH3

Hydrogen peroxide

Heat

'Precondensate'

Figure 2.14: THPC-urea-ammonia reaction (Proban process).


- 17 -

Another successful commercial approach to durable phosphorous-containing finishes is the use of

N-methylol dimethylphosphonopropionamide (Fig. 2.15) in combination with trimethylol

melamine and phosphoric acid as catalyst in a pad-dry- cure process (Pyrovatex process)

36 .The required add-on is 20-30 % depending on the weight of the fabric. In this process,

washing after curing is necessary to remove the phosphoric acid, leading to higher costs

associated with the second drying step. In addition, the finish may give rise to an unpleasant

odour during the curing step. Novel developments include higher product purity, decrease in

formaldehyde emission during curing and by the finished textile, and also higher fixation rates

enabled by moderate condensation conditions (accompanied by less fibre damage). Both

processes are justified by the common finishing practice.

N N

N NHCH2OHHOCH

2HN

NHCH2OH

P

OCH3O

CH3O CH

2CH

2CONHCH

2OH

P

OCH3O

CH3O CH

2CH

2CONHCH

2OCH

2

N N

N NHCH2Ocellulose

NHCH2OH

HN

+ Cellulose-OH+

-H2O Acid catalysed

The Pyrovatex process:1. Pad the Pyrovatex mixture.2. Dry at 120 oC.3. Cure at 160 oC for 3 min.4. Wash in dillute Na2CO3.

5. Wash in water.6. Dry and stenter to width.

N-methylol dimethylphosphonopropionamide Trimethyol melamine

Figure 2.15: Reaction between N-methyol dimethylphosphonopropionamide and cellulose.

2.5.6 Carboxylic acids as flame retardant finishes

Multifuncional carboxylic acids have started to be in use as non-formaldehyde durable press

finishing agents since the late 1980s 2, 13- 29 . In the field of flame retardancy the use of

polycarboxylic acid started by Blanchard and Graves. They investigated the application of

polycarboxylic acids to reduce flammability of cotton/polyester carpets 3, 38- 40 . Their results

showed a very good effectiveness of BTCA, citric acid and maleic acid. Phosphorus containing

oligomer of maleic acid as was also used to reduce the flammability of cotton/polyester fleece as


- 18 -

reported recently 4 . The treated cotton/polyester fleece had lower flammability and increased

char formation upon combustion.

In 2003 Yang and coworkers developed a system in which they used BTCA as a binder between

a hydroxy-functional organophosphorus oligomer and cellulose (Figure 2.16), what makes the

organophosphorus compound a durable flame retardant finish agent 41 .

OCH2CH

2OH P

O

OCH

OCH2CH

2O C CH

2

CH

CH

CH2

C O Cellulose

COOH

COOH

O

O

P

O

CH

OCH2CH

2O

2x

3 3

x

Figure 2.16: Binding of a hydroxy-functional organophosphorus oligomer to cellulose by BTCA.

However, the flame retardant properties quickly deteriorated as the number of home laundering

cycles was increased. Later it was found that the free carboxylic acid groups bound to the cotton

fabric form an insoluble calcium salt during home laundering, thus diminishing the flame

retardant properties of the treated cotton fabric.

They developed a new system were it was also found that the free carboxylic acid groups on the

treated cotton fabric were esterified by triethanolamine (TEA), and that the formation of calcium

salt on the fabric was suppressed by the esterification of the free carboxylic acid groups by TEA

42 . Yang by continuing a research in this field developed different binders that can be used for

cotton cellulose and some other fabrics for flame retardant treatments 43-45 .

Another flame retardant treatment for cellulose-containing materials was developed in which an

inexpensive citric acid was used as a replacement for more expensive BTCA in aim to reduce

finishing costs 46 .

2.5.7 Flame-retardant test methods

Many factors influence the flammability of textiles, including the fibre type, the fabric weight

and construction, the method of ignition, the extent of heat, and material exchange, and the

presence and the absence of flame retardants. Different performance requirements and

government regulations have led to the development of numberus test methods for evaluating the


- 19 -

flame retardancy of textiles 34 . According to a great variety of textile use there are numerous

test methods with vertical, horizontal or diagonal arrangement of the samples, methods with and

without air ventilation, and many special tests, for example carpets and fire protection clothing.

Some of the more commonly encountered tests are given in Table 2.1.

Table 2.1: Common flammability test methods.

Test method Sponsoring organisation Comments

16 CFR 1610 Consumer Product Safety

Commission (CPSC)

Fabric at 45° angle to flame for 1 s. For general

apparel.

16 CFR 1615/1616 CPSC Fabric held vertical to flame for 3 s. For children’s

sleepwear.

NFPA 1971 National Firefighters Protection

Association (NFPA)

Fabric held vertical to flame for 12 s. For protective

clothing.

NFPA 701 NFPA Fabric held vertical to flame for 45 s to 2min. For

drapery.

ASTM D-2863

Limiting oxygen index

(LOI)

ASTM Fabric held vertical in atmosphere of different

oxygen/nitrogen ratios and ignited from top.

Determines minimum oxygen level to support

combustion.

BS 5852 Part1 and 2,

for ignition sources

‘cigarette’ and ‘match’

equivalent also EN 1021

and EN 597

British Standards Institution Burning behaviour of upholstered furniture fabrics

(also for private use) against smoker-materials like

cigarettes and matches. Finished fabric must be

soaking resistant at 40 °C according to BS 5651,

then horizontally and vertically fixed on a mini

chair on a support of foamed PU, by seven ignition

methods.

ISO 6940/6941 International Standard

Organisation

Vertically held specimens, determination of the ease

of ignition/the flame spread properties.

DIN 54333 T1 Deutsches Institut für Normung Horizontally held specimens, because of the heat

distribution less severe than vertical tests.

A measure that enables an obvious assessment of flame protection properties is the limiting

oxygen index (LOI), determined according to the ASTM D-2863. The LOI defined as the content

of oxygen in an oxygen/nitrogen mixture that keeps the sample at the limit of burning:

LOI=22

21000

NO

O


- 20 -

3 ANALYTICAL METHODS

3.1 Introduction

The main spectroscopies employed to detect vibrations in molecules are based on the processes

of infrared absorption and Raman scattering. They are widely used to provide information on

chemical structures, to identify substances from the characteristic spectral patterns

(fingerprinting), and to determine quantitatively or semi- quantitatively the amount of a substance

in the sample. Samples can be examined in a whole range of physical states; for example, as

solids, liquids or vapours, in hot or cold states, in bulk, as microscopic particles, or as surface

layers. Raman scattering is less widely used than infrared absorption 46 .

3.2 Raman spectroscopy

3.2.1 Basic theory 46

When the light interacts with matter, the photons which make up the light may be absorbed or

scattered, or may not interact with the material and may pass straight through it. If the energy of

an incident photon corresponds to the energy gap between the ground state of a molecule and

exited state of the molecule, the photon may be absorbed and the molecule promoted to the

higher energy state (excited state). It is this change which is measured in absorption spectroscopy

by the detection of the loose of that energy of radiation of the light.

However it is also possible for the photon to interact with the molecule and scatter from it. In this

case there is no need for photon to have an energy which matches the difference between two

energy levels of the molecule. The scattered photons can be observed by collecting light at an

angle to the incident light beam, and provided there is no absorption from any electronic


- 21 -

transitions which have similar energies to that of the incident light, the efficiency increases as the

fourth power of the frequency of the incident light.

In Raman scattering, the light interacts with the molecule and distorts the cloud of electrons

round the nuclei to form a short lived state called a virtual state (polarizability). This state is not

stable and the photon is quickly re-radiated.

The energy changes we detect in vibrational spectroscopy are those required to cause nuclear

motion. If only electron cloud distortion is involved in scattering, the photons will be scattered

with very small frequencies changes, as the electrons are comparatively light. This scattering

process is regarded as elastic scattering and is the dominant process. For molecules it is called

Rayleigh scattering. However if nuclear motion is induced during the scattering process, energy

will be transferred either from the incident photon to the molecule or from the molecule to the

scattered photon. In these cases process is inelastic and the energy of the scattered photon is

different from that of the incident photon. This is Raman scattering. It is inherently a week

process in that only one in every 106-10

8 photons which scatter is Raman scattered.

Figure 3.1 shows the basic processes which occur for one vibration. At room temperature, most

molecules, but not all, are present in the lowest energy vibrational level. Since the virtual states

are not real states of the molecule but are created when the laser interacts with the electrons and

causes polarizability, the energy of these states is determined by the frequency of the light source

used. The Rayleight process will be the most intense process since most photons scatter this way.

It does not involve any energy change and consequently the light returns to the same energy state.

Stokes Rayleight anti-Stokes

Vibrationalstates

Virtualstates

n

m

Figure 3.1: Diagram of the Raylight and Raman scattering processes.


- 22 -

The Raman scattering process from ground vibrational state m leads to absorption of energy by

the molecule and its promotion to a higher energy exited vibrational state (n). This is called

Stokes scattering. However, due to thermal energy, some molecules may be present in an excited

state such as n in Figure 3.1. Scattering from these states to the ground state m is called anti-

Stokes scattering and involves transfer of energy to the scattered photon. The relative intensities

of the two processes depend on the population of the various states of the molecule. In each case

the energy of the virtual state is defined by the energy of the incoming laser. The two states

marked as m and n are different vibrational states of the ground electronic state.

Most molecules at rest prior to interaction with the laser and at the room temperature are likely to

be in the ground vibrational state. Therefore the majority of Raman scattering will be Stokes

Raman scattering.

Use of Near Infrared (NIR) laser and an interferometer with detection using and Fourier

Transform (FT) program is most usefully for having Raman spectra of as many samples as

possible (Fig. 3.2). NIR laser is emitting at 1064 nm. As a result few molecules have excited

states low enough in energy to give fluorescence. Since the excited radiation does not absorb in to

the most samples the laser power usable are relatively high. Interferometer detection system,

which is essentially the FT- based system used in infrared spectrometers, is very sensitive. This

instrument is closer to an infrared system in that it can record Raman scattering from a wide

range of materials present in different states, it is non-contact and samples require a little or no

preparation.

Figure 3.2: NIR FT instrument schematic 47 .


- 23 -

3.3 Infrared (IR) spectroscopy

3.3.1 The theoretical principles of FT- IR

Infrared spectroscopy has been employed for both qualitative and quantitative analysis. It is on of

the most powerful and important tools available to the chemist for identifying and determining

the structure of organic, inorganic, and biochemical species. All molecular species absorb

infrared radiation with exception of a homonuclear species 48 .

Infrared absorbtion arises because a molecule absorbs infrared radiation energy in the transition

from one vibration state to another 49 . Molecular vibration frequencies are determined by the

interatomic distances, bond angles, and force constants of a molecule, rather than by the bulk

properties of the compound 50 .

The dipole moment of the molecule changes with the change in interatomic distance of a

vibrating heteropolar diatomic molecule by stretching and bending. Such a vibrating diatomic

molecule produces a stationary alternating electric field the magnitude of which changes

periodically with time at a frequency equal to the vibration frequency. This stationary electric

field interacts with the moving electric field of electromagnetic radiation. If the diatomic

molecule is homopolar, there is no dipole-moment change with vibration and no altering dipolar

electric field is produced. The same explanation may be applied to polyatomic molecules which

have elements of symmetry. An absence of dipolar-moment change in these cases is the result of

certain symmetry relationships and such molecules are not ‘infrared active’ 49 .

A vibrating hetero polar diatomic molecule with its stationary altering electric field is exposed to

infrared radiation which consists of a moving alternating electric field. The molecular vibration

frequency must be identical to the frequency of the incident radiation, if the molecule is to absorb

energy of the radiation quantum. If the frequency of the applied radiation is not equal to the

molecular vibration frequency, no interaction between the molecule and radiation occurs that can

lead to a change in vibrational state. These two situations result in absorbtion spectrum of the

molecule. The frequency range over which absorbtion occurs is generally referred to as an

absorbtion band 49 .

The infrared fundamentals of interest to chemist fall between 4000 cm-1

and 400 cm-1

. Although,

this absorbtion is quantized, the vibrational spectra do not consist of discrete lines but appear as


- 24 -

bans, because a single vibrational energy change is accompanied by a number of rotational

energy changes. The intensity of the infrared band is proportional to the square of the rate of

change of the dipole moment of the molecule as atoms pass through their equilibrium position

during the corresponding vibration and it is measured in transmission or absorbance units 49 .

3.3.2 Attenuated total reflectance Fourier transform spectroscopy (ATR

FT-IR Spectroscopy)

An infrared spectrum obtained by reflection of radiation from the surface of a chemical material

usually produces a spectrum of poor quality. However, with attenuated total internal reflectance

(ATR) IR spectra of a much higher quality can be obtained 49 . If infrared radiation enters a

prism made of a high refractive index infrared transmitting material (ATR crystal) it will be

totally internally reflected 51 .

This internal reflectance creates the evanescent wave which extends beyond the surface of the

crystal into the sample held in contact with the crystal. In the region of the infrared spectrum

where the sample absorbs energy, the evanescent wave will be attenuated.

The depth to which the evanescent wave extends into the sample is known as depth of penetration

and it is defined as the distance from the crystal-sample interface where the intensity of the

evanescent wave decays to approximately 37% of its original value. The penetration depth of the

infrared energy into the sample is wavelength dependent. As the wavelength of the infrared

radiation increases, the depth of penetration also increases. This leads to the relative band

intensities in the ATR IR spectrum. The refractive index of the ATR crystal has two effects on

the ATR IR spectrum obtained. With increasing refractive index of the crystal material, critical

angle is decreased. Because the conditions for total internal reflectance require the angle of the

incident radiation to exceed the critical angle; distortions in the infrared spectrum sample will be

observed if the angle of incidence does not greatly exceed the critical angle. By increasing the

refractive index of the ATR crystal, the depth of penetration will decrease. This will decrease the

Effective Pathlenght and therefore decrease the absorbance intensity of the spectrum 51 .

The evanescent wave decays very rapidly with distance from the surface. It is important to get the

sample in intimate contact with the crystal. This is easy to achieve with most liquids, but for

solids, a pressure device which presses the sample against the crystal has to be used. The area of


- 25 -

sample contact directly affects the intensity of the absorbance spectrum; for maximum

reproducibility in a series of measurements, the entire crystal surface should be covered by the

sample 51 . Figure 3.3 shows a single bounce ATR, material used is diamond.

Figure 3.3: Single bounce ATR 52 .

The material most commonly used for ATR IR spectroscopy are ZeSe, Ge, KRS-5, Si, AMTIR

and Diamond as shown in Table 3.1. Diamond is easily used for analysis of a wide range of

samples, including acids, bases, and oxidizing agents, scratch and abrasion resistant, expensive,

intrinsic absorption from approximately 2300 to 1800 cm-1

limits its usefulness in this region (5%

transmission) 51 .

Table 3.1: Common crystal materials used in ATR IR spectroscopy 53 .

MATERIAL Useful Spectral

Range / cm-1

*

Refractive index at

1000 cm-1

Depth of Penetration at

45° / µ **

Depth Penetration at

60° / µ **

AMTIR 11,000 -725 2.5 1.46 0.96

Diamond 4,500 - 2,500

1,667 - 33 2.4 1.66 1.04

Ge 5,500 - 830 4 0.65 0.50

KRS-5 20,000 - 400 2.37 1.73 1.06

Si 8,300 - 1,500

360 - 70 3.4 0.81 0.61

ZnSe 20,000 - 650 2.4 1.66 1.04

*The useful spectral range for ATR materials is often different than that shown in transmission tables. Transmission measurements are reported for relatively thin crystals. In the ATR experiment, the IR beam travels a much longer distance (2,54 – 7,62 cm). This affects the overall spectral

range. Some crystals may totally absorb in certain regions (Si, diamonds).

** The depth of penetration results were calculated for a sample with refractive index of 1.4 at 1000 cm-1


- 26 -

3.4 Comparison between IR an Raman spectroscopy-

Molecular vibrations 46

Provided that there is no change in electronic energy, for example, by the absorption of a photon

and the promotion of an electron to an excited electronic state, the energy of a molecule can be

divided into a number of different parts or ‘degrees of freedom’. Three of these degrees of

freedom are taken up to describe the translation of the molecule in space and three to describe

rotational movement except for linear molecules where only two types of rotation are possible.

Thus, if N is the number of atoms in a molecule, the number of vibrational degrees of freedom

and therefore the number of vibrations possible is 3N-6 for all molecules except linear ones

where it is 3N-5. For a diatomic molecule, this means there will be only one vibration. In a

molecule such as oxygen, this is simple stretch of the O–O bond. This will change the

polarizability of the molecule but will not induce any dipole change since there is no dipole in the

molecule and the vibration is symmetric about the centre. This means, that oxygen gas will give a

band in the Raman spectrum and no band in the infrared spectrum. In a molecule such as nitric

oxide, NO, there will be only one band, since there is both a dipole change and a polarizability

change, it will appear in both the infrared and Raman spectrum.

A triatomic molecule will have three modes of vibration; these are a symmetrical stretch, a

bending or deformation mode and an asymmetrical stretch as shown in Figure 3.4. The very

different water and carbon dioxide molecules clearly demonstrate these vibrations

Figure 3.4: Spring and ball model – three modes of vibration for H2O and CO2


- 27 -

This simple model is widely used to interpret vibrational spectra. However, the molecule actually

exists as three-dimensional structure with a pattern of varying electron density covering the

whole molecule. A simple depiction of these for carbon dioxide is shown in Figure 3.5.

Figure 3.5: Electron cloud model of carbon dioxide showing an IR and Raman active vibrations

If either molecule vibrates, the electron cloud will alter as the positive nuclei change position and

depending on the nature of the change, this can cause a change of dipole moment or polarization.

In these triatomic molecules, the symmetrical stretch causes large polarizability changes and

hence strong Raman scattering with weak or no dipole change and hence weak or no infrared

absorption. The deformation mode causes a dipole change but little polarizability change and

hence strong infrared absorption and weak or non-existent Raman scattering.


- 28 -

3.5 Atomic spectroscopy

Atomic spectroscopy is used for the qualitative and quantitative determination of 70 elements

50 . The basic aim of analytical atomic spectroscopy is to identify elements and quantify their

concentrations in various media. The procedure consists of three general steps: atom formation,

excitation, and emission. Before excitation, an element that is bound in a specific matrix must be

separated from that matrix so that its atomic emission spectrum is free from interferences. For

UV and visible spectroscopy, the input energy must be sufficient to raise an electron from the

ground state to the excited state. Once the electron is in the excited state, the atom emits light,

which is characteristic for that particular element 54 .

Spectroscopy determination of atomic species can only be performed on a gaseous medium in

which the individual atoms (or sometimes elementary ions such as Fe+, Mg

+, or Al

+) are well

separated from another. Consequently, the first step in all atomic spectroscopic procedures is

atomization, a process in which the sample is volatilized and decomposed to produce an atomic

gas. Several methods are used to atomize samples for atomic spectroscopic studies, such as

atomic absorption spectroscopy (AAS), atomic emission spectroscopy (AES), and atomic

fluorescence spectroscopy (AFS) etc. In our research analysis with inductively coupled plasma

atomic emission spectroscopy (ICP-AES) were carried out 48 .

3.5.1 Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-

AES) 56

Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) is one of several

techniques available in analytical atomic spectroscopy. ICP-AES utilizes plasma as the

atomization and excitation source. Plasma is an electrically neutral, highly ionized gas that

consists of ions, electrons, and atoms. Most analytical plasmas operate with pure argon or helium,

which makes combustion impossible. Plasmas are characterized by their temperature, as well as

their electron and ion densities. Analytical plasmas typically range in temperature from 600 to

8,000 K. Figure 3.6 summarizes the steps involved in determining the elemental content of an

aqueous phase sample by ICP-AES.


- 29 -

Figure 3.6: Steps involved in the analysis of aqueous samples by ICP-AES.


- 30 -

4 EXPERIMENTAL

The purpose of our research was to investigate the chemical reactions of maleic acid (MA) on

cotton in the presence of sodium hydroxyphosphinite (SHP), and the use of the combination of

MA and SHP as a flame retardant finishing system for cotton.

Research was divided into two parts:

I. Investigation of reactions of MA with SHP:

Mixtures of MA and catalyst SHP were prepared in different molar ratios, heated at

elevated temperatures for different time periods, cooled to a room temperature, and ATR-

FT IR and Raman analysis were carried out. In such way the influence of time, temperature

and molar ratio on the reaction mechanism was studied.

II. Introduction of MA/SHP as flame retardant finishing system for cotton cellulose:

The combination of MA and SHP as a flame retardant finishing system was used for cotton

fabrics. Studies of esterification mechanism of MA and cotton cellulose, further reactions

of SHP with esterified MA, which leads to the crosslinking of cotton cellulose, were

carried out. Studies of treatments to see effectiveness in reducing the flammability of

cotton fabrics were done.

Research work has been done in cooperation between Faculty of Mechanical Engineering and

Department of Textiles, Merchandising and Interiors of University of Georgia, Athens, Georgia,

USA.


- 31 -

4.1 Materials

Two types of cotton textile substrates were used:

- Plain, woven cotton fabric (100%) that was desized, scoured, bleached, and mercerised,

with mass of 140 g/m2.

4.2 Chemicals

Maleic acid (MA), (Z)-Butenedioic acid (IUPAC), produced by Merck, M (C4H4O4) = 116,07

g/mol, 99% pure.

CC

CC

OH

OH

O

O

H

H

Maleic anhydride, Furan-2,5-dione (IUPAC), produced by Merck, M (C4H2O3) = 98,06 g/mol,

99% pure.

CC

CC

O

O

O

H

H

Sodium hydrogen phosphate (I) (SHP), sodium hypophosphite, sodium hydroxyphosphinite

(IUPAC), produced by Riedel de Haën, M ( NaH2PO2 x H2O) = 105,99 g/mol, 99% pure.

P

O

H H

O Na+_

Disodium hydrogen phosphate (III) (DSHP), sodium phosphite, disodium hydrogen phosphite

(IUPAC), produced by Sigma-Aldrich, M (Na2HPO3 5H2O) = 216,04 g/mol, ≥98% pure


- 32 -

P

OH

O ONa+

Na+_ _

Sodium hydroxide, produced by Riedel de Haën, M (NaOH) = 40, 00 g/mol, 99% pure

4.3 Analytical Methods

4.3.1 Raman Spectroscopy

Samples were analysed using Perkin Elmer Spectrum GX NIR-FT Raman spectrometer. KBr

beam splitter was used, 32 scans were obtained, gain was 1 and laser power was 1000 mV.

4.3.2 ATR-FT IR Spectroscopy

Samples were analysed using Perkin Elmer Spectrum GX FT-IR spectrometer with a Golden

Gate Attenuated Total Reflection (ATR) attachment with a diamond crystal. KBr beam splitter

was used, 16 scans were obtained, resolution and gain was 4.

4.3.3 ICP Atomic Emission spectroscopy

Thermo-Farrell-Ash Model 965 inductively coupled plasma atomic emission spectrometer was

used to determine the phosphorus content.

4.4 Experiments

4.4.1 Preliminary studies of MA/SHP mixtures

Mixtures of maleic acid and catalyst SHP were prepared in different molar ratios. Molar ratio is

listed of MA/SHP is listed in Table 4.1. Mixtures were mixed in the mortar until the homogenous

fine powder was obtained. Prepared mixtures were heated at elevated temperatures for different

time, cooled to a room temperature and ATR-FT IR and Raman analysis were carried out.

The influence of MA/SHP molar ratio, temperature and time of reaction (see Table 4.1) were

studying by using of ATR-FT IR and Raman spectroscopy.


- 33 -

Table 4.1: Treatment characteristics of samples (MA, and mixtures MA/SHP).

Sample n (MA) / mol n (SHP) / mol Tcuring / °C tcuring / min

S1 1 - - -

S2 1 - 150 1

S3 1 - 150 2

S4 1 - 150 4

S5 1 - 150 6

S6 1 - 150 8

S7 1 1 - -

S8 1 1 120 2

S9 1 1 140 2

S10 1 1 150 2

S11 1 1 160 2

S12 1 1 120 3

S13 1 1 140 3

S14 1 1 150 3

S15 1 1 160 3

S16 1 1 150 0,5

S17 1 1 150 1

S18 1 1 150 2

S19 1 1 150 4

S20 1 1 150 6

S21 1 0,1 150 3

S22 1 0,25 150 3

S23 1 0,5 150 3

S24 1 1 150 3

S25 1 2 150 3

S26 1 0,1 150 4

S27 1 0,25 150 4

S28 1 0,5 150 4

S29 1 1 150 4

S30 1 2 150 4

S31 1 0,1 150 5

S32 1 0,25 150 5

S33 1 0,5 150 5

S34 1 1 150 5

S35 1 2 150 5


- 34 -

Mixtures of MA and another catalyst DSHP were prepared. Mixtures in different molar ratios

were prepared and heated for 3, 4 and 5 minutes at 150 ºC as shown in Table 4.2. FT-Raman and

FT-IR analyses of cooled mixtures MA/ DSHP were done.

Table 4.2: Treatment characteristics of samples (MA/DSHP mixtures).

Sample n (MA) /mol n (DSHP) /mol Tcuring / °C tcuring / min

S36 1 0,1 150 3

S37 1 0,25 150 3

S38 1 0,5 150 3

S39 1 1 150 3

S40 1 2 150 3

S41 1 0,1 150 4

S42 1 0,25 150 4

S43 1 0,5 150 4

S44 1 1 150 4

S45 1 2 150 4

S46 1 0,1 150 5

S47 1 0,25 150 5

S48 1 0,5 150 5

S49 1 1 150 5

S50 1 2 150 5

4.4.2 Treatments of cellulose fabrics with maleic acid with addition of SHP

or DSHP

To carry out the reactions MA on cotton in the presence of SHP or DSHP, solutions of MA/ SHP

in different mole ratios and solutions of MA/DSHP in different mole ratios were prepared as

shown in Tables 4.3 and 4.4. For these treatments plain, desized, scoured and mercerized woven

cotton fabric material was used.


- 35 -

Table 4.3: The concentrations of MA and SHP used for the treatment of the cotton fabrics.

Sample Molar

ratio

MA SHP Tcuring

(°C)

tcuring

(min) W/V

(g/l) n (mol/l)

W/V

(g/l) n (mol/l)

S51 1:0,05 60 0,54 2,4 0,027 165 3

S52 1:0,12 60 0,54 6 0,067 165 3

S53 1:0,25 60 0,54 12 0,14 165 3

S54 1:0,5 60 0,54 24 0,27 165 3

S55 1:1 60 0,54 48 0,54 165 3

Cotton fabrics were padded with prepared solutions to give wet pick up of 95 to 105%. Treated

fabrics were suspended in a forced draught oven and predried at 110 ºC for 10 minutes. Then

fabrics were cured in Werner Mattis thermo fixation equipment at 165 ºC for 3 minutes. All

samples were rinsed. On treated cotton samples wrinkle recovery angle was measured according

to the DIN 53 890 standard. Treated fabrics were also immersed in to the 0.1 M solution of

NaOH for 2 minutes and dried (FT-IR analysis).

Table 4.4: The concentrations of MA and DSHP used for the treatment of the cotton fabrics.

Sample Molar

ratio

MA DSHP Tcurring

(°C)

tcurring

(min) W/V (g/l) n (mol/l) W/V (g/l) n (mol/l)

S56 1:0,05 60 0,54 3,4 0,027 165 3

S57 1:0,12 60 0,54 9 0,067 165 3

S58 1:0,25 60 0,54 17 0,14 165 3

S59 1:0,5 60 0,54 34 0,27 165 3

S60 1:1 60 0,54 68 0,54 165 3


- 36 -

For determination of phosphorus concentration cotton material was used. Material was immersed

in solutions containing MA/SHP (different molar ratios); dried at 90°C for 3 min 45 sec, and then

cured at 170 °C for 4 min. Treatment conditions are shown in Table 4.5.

Table 4.5: The concentrations of SHP and MA used for the treatments of the cotton fabrics.

Sample Molar

ratio

MA SHP Tcuring

(°C)

tcuring

(min) W/V

(g/l) n (mol/l)

W/V

(g/l) n (mol/l)

S61 1:0,12 60 0,54 6 0.067 170 4

S62 1:0,25 60 0,54 12 0,14 170 4

S63 1:0,5 60 0,54 24 0,27 170 4

S64 1:0,6 60 0,54 48 0,32 170 4

Treated fabrics were subjected to one home laundering. After it, determination of phosphorus

concentration by ICP-AES was done.

4.4.3 Preparation of samples for determination of phosphorus fixation

by ICP AES

The treated fabric specimens were conditioned to constant weight before the analysis.

Approximately 2 g of the treated fabric taken from 3 different parts in a fabric specimen was

ground in a Wiley mill into a powder, and the powder was thoroughly mixed to improve sample

uniformity. 2 ml of concentrated H2SO4 was added to 0,10 g of cotton powder in a beaker. 10 ml

30% H2O2 was added drop wise to the mixture, allowing the reaction to subside between drops.

The reaction mixture was then heated at approximately 250°C to digest the powder and to

evaporate the water until a dense SO3 vapour was produced. The completely digested cotton

sample as a clear solution was transferred to a 50 ml volumetric flask, and then diluted with

distilled water to the mark. The sample thus prepared was analyzed with a Thermo-Farrell-Ash

Model 965 inductively coupled plasma atomic emission spectrometer to determine the

phosphorus concentration.

The percent phosphorus fixation (%Pfix) is calculated as shown in equation:


- 37 -

is the phosphorus concentration after 1 home laundering, and

is the phosphorus concentration before laundering.

4.4.4 Wrinkle Recovery Angle (WRA) according to DIN 53 890 standard

Cotton fabrics were exposed to the moving air in the standard atmosphere for preconditioning

before sampling. After preconditioning for at least 24 hours at 20 °C and humidity 65 2 %,

specimens of each fabrics in dimensions 15 x 40 mm were cut. Ten specimens were cut in their

long dimension parallel to the warp, and ten were cut with their long dimension parallel to the

filling. Each specimen was folded, covered with a glass plate and a load of 1,0 kg was applied.

Five specimens of each group have to be folded on one side and five on another side, whether or

not the fabric has a definite face or back. After 30 minutes the load was removed and the

specimen inserted by the exposed end in the slot of the tester. After 5 and 30 minutes of the

removal of the load, the wrinkle recovery value was read from the scale.

The average recovery in degrees for each of the specimens was calculated. The difference

between face to face and back to back average readings was not greater than 15 degrees, so just

warp and all fillings were averaged separately, as a result the average of average warp and of

average filling recovery angle after 30 minutes in degrees is reported.


- 38 -

5 RESULTS AND DISCUSSION

5.1 Preliminary studies of MA/SHP mixtures

In preliminary studies reactions between maleic acid (MA) and sodium hydroxyphosphinite

(SHP) or disodium hydrogen phosphite (DSHP) in solid state at different conditions were

investigated. For this purpose FT-Raman and FT-IR analysis were carried out.

5.2 FT-Raman analysis

Figure from 5.1 to 5.4 shows Raman spectra of maleic acid (MA), maleic anhydride (MAnh),

SHP, and DSHP at room temperature

Figure 5.1: Raman spectrum of maleic acid (MA).

3500,0 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 600 400 200 100,0

0,0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

32

34

36

37,7

Raman Shift / cm-1

Int

3060,45

1722,94

1586,41

1568,35

1371,59

1263,18

1223,03

1020,25

951,99791,38 616,71

405,90

311,54

327,60

864,43

1636,02

1700,95


- 39 -

In Raman spectrum of MA (Figure 5.1) it is clearly indicated a band at 3060 cm-1

associated to

stretching mode of =C-H bond. In Raman spectrum of Maleic anhydride (Figure 5.2) bands

associated with stretching mode of =C-H bond can assigned at 3122 cm-1

. Bands for anhydride

can be clearly seen at 1850 and 1780 cm-1

.

Figure 5.2: Raman spectrum of Maleic anhydride (MAnh).

Figures 5.3 and 5.4 show Raman spectra of SHP and DSHP.

3500,0 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 600 400 200 100,0

0,0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

32

34

34,9

Raman Shift / cm-1

Int

1061,17

873,41

768,353122,44

3131,41

3189,043060,28

2888,83

1624,23

1632,74

1594,48

1309,20

1290,301268,58

1241,65

1061,32

957,41 839,80

1842,70

1858,89

1786,89

1753,07

1738,96

410,30271,35

643,16


- 40 -

Figure 5.3: Raman spectrum of sodium hydroxyphosphinite (SHP).

Figure 5.4: Raman spectrum of disodium hydrogen phosphite (DSHP).

3500,0 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 600 400 200 100,0

0,00

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

4,5

5,0

5,5

6,0

6,53

Raman Shift / cm-1

Int 2355,49

2328,05

2281,651222,11

1169,19

1160,06

1100,49

1074,47

1058,49

938,60

929,92

824,23

471,05

3500,0 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 600 400 200 100,0

0,02

0,2

0,4

0,6

0,8

1,0

1,2

1,4

1,6

1,8

2,0

2,2

2,4

2,6

2,8

3,00

Raman Shift / cm-1

Int

455,41

974,00

1014,97

1042,07

1059,18

1091,62

2340,74


- 41 -

When maleic acid is heated in the presence of SHP, the addition of SHP on the double C=C bond

can be expected. We studied the influence of temperature and time of heating on the disappearing

of C=C double bond in unsaturated dicarboxylic acid (MA).

5.2.1 The influence of temperature of heating

First FT-Raman analysis of maleic acid and SHP and a mixture MA/SHP in molar ratio 1:1 at

room temperature were carried out. Fig. 5.5 shows Raman spectra of MA, SHP and the mixture

of MA/SHP. In Raman spectrum of MA/SHP mixture it is possible to see beside bands from both

components (MA and SHP) two new bands at 2429 and 2452 cm-1

.

Figure 5.5: Raman spectra of MA, SHP and a mixture of MA/SHP (molar ratio 1:1) at room

temperature.

3500,0 3000 2000 1500 1000 500 100,0 Raman Shift / cm-1

Int

MA/SHP mixture before heating

MA

SHP

2358,20

1074,58

940,47 929,29

1219,88

2358,20

1635,64

864,47

614,11

1700,47

1722,82

1074,58

1020,94 940,47

929,29 951,64

1219,88

1331,64

1367,41 1264,58

1568,58 1586,47

3061,19

864,47

614,11

1700,47

1722,82 1020,94

951,64

1219,88 1331,64

1367,41 1264,58 1568,58 1586,47

3061,19

1635,64

2429 cm-1

2452 cm-1


- 42 -

To see what is happening in the mixture at room temperature, spectra at different times after

mixture was prepared were measured. Spectrum marked as a) (Sample S7, Table 4.1) is scanned

immediately after mixture was prepared. It is possible to see that no new peaks appear. Two new

peaks at Raman shift of 2447 and 2429 cm-1

start to appear after a couple of minutes, when the

next spectrum (Spectrum marked as b) was obtained. Their intensities increase after each

measurement. Peak at 2358 cm-1

which is assigned to P-H stretch is losing its intensity if we keep

the mixture (1:1 molar ratio) for a long time at room temperature (Fig. 5.6). We can also observe

that the same trend of decreasing in intensity is happening with peaks at 1074 and 1099 cm-1

which are also assigned to SHP functional groups. After one week there are also changes in

spectrum regarding functional groups of maleic acid (Spectrum marked as d). There is a new

peak at 2935 cm-1

which can be assigned to saturated -C-H stretch, at the same time the intensity

of the band around 3050-3060 cm-1

,which is related to stretching mode of =C-H bond is

decreasing.


- 43 -

Figure 5.6: Raman spectra of MA/SHP mixtures (molar ratio 1:1) at room temperature at

different times;

– Spectrum a) was taken immediately after MA an SHP were mixed,

– Spectrum b) was taken after 10 minutes,

– Spectrum c) was taken after 20 minutes and

– Spectrum d) was taken after a one week.

From observations we can conclude, that MA and SHP start to react even at room temperature.

Mixtures MA/SHP in the same molar ratio (1:1) were heated for 2 minutes at different

temperatures as presented in Table 4.1(Samples S8-S11).

3500,0 3000 2000 1500 1000 500 100,0 Raman Shift / cm-1

Int

b)

c)

d)

a)

2358,20 3061,19

1074,58 1099,17

2429,85

2447,76 2358,20 3061,19

1074,58

1099,17

2429,85

2447,76 2358,20 3061,19

1074,58

1099,17

2429,85 2447,76

2931,34

1745,17 1074,58


- 44 -

Figure 5.7 presents Raman spectra of MA/SHP mixtures in molar ratio 1:1, heated at 120, 140,

150 and 160 ºC for 2 minutes.

From spectra in Figure 5.7 we can see that band for the stretching mode of =C-H bond (at around

3050-3060 cm-1

) start to decrease when a mixture is heated at 160 ºC for 2 minutes. In the same

spectrum we can also observe increasing of peak at 2935 cm-1

, which could be assigned to

stretching mode of unsatured -C-H functional group of MA. The band around 1635-1645 cm-1

which can be assigned to the C=C stretch of MA is still remaining what confirms that reaction

did not take place completely.

Figure 5.7: Raman spectra of MA/SHP mixtures (1:1 molar ratio) heated at temperatures from

120 to 160 °C for 2 minutes.

3500,0 3000 2000 1500 1000 500 100,0 Raman Shift / cm-1

Int

120 °C

140 °C

150 °C

160 °C

2385,07 3061,19

1745,17

1722,82 1700,47

1662,47

1635,64 1394,23

1586,47 1568,58

1331,64

1242,23

1219,88

1121,52

866,70 1079,05

1020,94

2385,07 3052,23

1711,64

1662,47

1620,00

1394,23

1217,64

1152,82

1088,00

1121,52

868,94 924,82

1047,76

801,88

296,70

2385,07 2940,29

3052,23

1704,94

1646,82 1394,23

1152,82

1210,94 1088,00

1121,52

1047,76

927,05

866,70

801,88

2385,07

3070,14 1745,17 1713,88 1662,47

1620,00

1385,29

1242,23

1219,88

1121,52 868,94

801,88

1012,00 980,70


- 45 -

For this reason a new mixtures of MA/SHP in the same molar ratio was prepared (samples: S12-

S15; Table 4.1). Mixtures were heated at elevated temperatures for 3 minutes (Fig.5.8). From Fig.

5.8 (spectra of samples S12-S15) we can observe that the reaction between MA and SHP was

successful at temperature 160 ºC when the time of reaction was 3 minutes (sample S15). At this

conditions of treatment we can observe a new band at 2940 cm-1

, which could be assigned to the

stretching mode of unsatured C-H functional group, band associated to the stretching mode of

=C-H bond (at around 3061 cm-1

) disappeared completely. The band around 1640 cm-1

which can

be assigned to the C=C stretch of MA disappeared to. The intensities of bands at 2385 cm-1

, 1159

cm-1

, 1074 cm-1

and at 929 cm-1

which are associated with P-H of SHP also significantly decrease

when the mixture was heated for 3 minutes at 160 ºC. Band at 1047 cm-1

which is assigned to

PO2 symmetric stretch still remains that means our reaction was successful.


- 46 -

Figure 5.8: Raman spectra of MA/SHP mixtures (1:1 molar ratio), spectrum of mixture at

ambient temperature (sample S1) and mixtures heated at elevated temperatures (samples S12-

S15) for 3 minutes.

For better resolution spectra of MA/SHP in molar ratio 1:1, heated at 120, 150 and 160 ºC for 3

minutes in the range from 1924 to 3316 are presented (Fig 5.9). It is more clearly to see the

appearing of a new band at around 2940 cm-1

(spectrum d) and disappearing of bands at around

3060 and 2355 cm-1

.

3500,0 3000 2000 1500 1000 500 100,0 Raman Shift / cm-1

Int

T= 120 °C

T= 140 °C

T=150 °C

T= 160 °C

Room T

3056,71

2358,20

1700,47

1635,64

1588,70 1568,58

1722,82 1331,64 1222,11

1074,58

929,29 864,47

1099,17

1159,52

3056,71 1394,23 868,94

1047,76

1155,05 1217,64

3056,71 1394,23 868,94

1047,76

1155,05

1217,64

3056,71

1707,17

1649,05 1394,23 868,94 1047,76 1155,05

1217,64

2940,29 1421,05


- 47 -

Figure 5.9: Raman spectra of MA/SHP mixtures (Samples S7, S12, S14 and S15, Table 4.1) in the

range from 3316 till 1924 cm-1

:

Mixture MA/SHP at room temperature (spectrum a),

Mixtures of MA/SHP heated at 120 and 150 ºC (spectra b and c) and

Mixture MA/SHP heated at 160 ºC (spectrum d).

5.2.2 The influence of time of heating

To study the influence of time of heating of mixtures on the reaction between MA and SHP,

mixtures were prepared samples of mixtures MA/SHP in molar ratio 1:1, heated at 150 °C for 0,5

min, 1, 2, 4, and 6 min (samples from S16 to S20, Table 4.1).

3316,4 3200 3000 2800 2600 2400 2200 2000 1924,0 0,01

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

4,5

5,0

5,5

5,96

Raman Shift / cm-1

Int

a)

b)

c) d)

2940,82

2355,75

2318,56 2452,44

2430,12

3061,06


- 48 -

When the mixture was heated for 4 minutes (sample S19) the band for stretching mode of

unsaturated =C-H bond band at 3061 cm-1

start to decrease and we can also observe increasing of

a new band around 2940 cm-1

, which could be assigned to stretching mode of saturated C-H

functional group. The intensities of bands at 2385 cm-1

, 1074 cm-1

and around 929 cm-1

which are

associated with P-H of SHP also decrease. If the mixture was heated for 6 minutes a band at 1047

cm-1

assigned to PO2 symmetric stretch of SHP and the band around 1640 cm-1

which is assigned

to the C=C stretch of MA are still present (Fig.5.10).

Figure 5.10: Raman spectra of MA/SHP mixtures (1:1 molar ratio) heated at T= 150 °C for

different times (samples: S16-S20, Table 4.1).


- 49 -

From spectra in Fig. 5.10 we can observe, the reaction between MA and SHP did not take place

completely even after the mixture MA/SHP was heated for 6 minutes at 150 ºC. We can conclude

that if the MA/SHP mixture is heated for 4 minutes at elevated temperature, the reaction between

MA and SHP starts, but it is not completed yet when mixture is heated for 6 minutes.

5.2.3 Heating of MA at 150 ºC for different times without adding a

catalyst

Maleic acid (MA) without adding the catalyst SHP was heated at 150 °C for different time (Table

4.1, samples: S2-S6).

Figure 5.11 presents Raman spectra of MA (sample S1) and maleic anhydride (MAnh) at ambient

temperature and of MA heated at 150 °C for different times (samples: S2-S6).

From spectra in Fig.5.11 is possible to observe at what time the anhydride starts to form.


- 50 -

Figure 5.11: Raman spectra of MA and MAnh at ambient temperature and MA heated at 150 ºC

for different times.

For better explanation Raman spectra of MA and maleic anhydride at ambient temperature and

maleic acid heated at T= 150 ºC for 6 minutes in range from 3253 till 2999 cm-1

were carried out

(Figure 5.12). It is possible to see that after maleic acid is heated at elevated temperature for 6

minutes new bands at 3188, 3131 and 3122 cm-1

appear, they can be associated with bands of

C=C stretch of maleic anhydride.

3500,0 3000 2000 1500 1000 500 100,0 Raman Shift / cm-1

Int

2 min

4 min

1 min

6 min

8 min

Maleic Anhydride

Ambient

3119,40 3186,56

1843,52 1856,94

1061,17 768,35

643,17

3119,40

3186,56 1843,52

1856,94 1061,17 768,35

643,17

3119,40 3186,56 1843,52 1856,94 1061,17

768,35 643,17


- 51 -

Figure 5.12: Raman spectra of MA (a)) and maleic anhydride (b)) at ambient temperature and

MA heated at T= 150 ºC for 6 minutes(c)) and in region from 3253 till 2999 cm-1

.

In Figure 5.13 Raman spectra of MA and MAnh at ambient temperature and MA heated at T=

150 ºC for 6 minutes in range from 1891 till 1815 cm-1

are presented. Also in this range it is

obviously to see, that after MA was heated for 6 minutes formation of anhydride starts, as new

peaks at 1858 and 1842 cm-1

appear which are associated with functional groups of MAnh.

Date: 24.5.2007

3253,9 3240 3200 3160 3120 3080 3040 2999,4

0,03

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

4,5

5,0

5,5

6,0

6,5

7,0

7,5

8,0

8,5

9,0

9,5

10,0

10,5

11,0

11,38

Raman Shift / cm-1

Int

2 min

4 min

1 min

Maleic Anhydride

Ambient

b)

c)

a)

3122,73

3131,19

3188,18

3060,41

3060,41

3122,73

3131,19

3188,18


- 52 -

Figure 5.13: Raman spectra of MA (a)) and MAnh (b)) at ambient temperature and of MA heated

at T= 150 ºC for 6 minutes (c)) in region from 1891 till 1815 cm-1

.

From Raman spectroscopy data we can conclude that when MA is heated at 150 °C for 6 minutes

without SHP the formation of anhydride occurred.

5.2.4 The influence of molar ratio of MA and SHP

Samples of MA/SHP in molar ratios: 1:0.1, 1:0.25, 1:0.5, 1:1 and 1:2, were heated for 3, 4 or 5

minutes at 150 ºC. Figure 5.14 shows spectra of MA/SHP mixtures in different molar ratio heated

for 4 minutes at 150 ºC (samples: S21-S25, Table 4.1).

From spectrum of mixture MA/SHP (molar ratio 1:0.1) we can observe increasing intensity of

new bands at 3116, 1854, 1840, 1783 cm-1

which can be assigned to formation of anhydride.

Date: 24.5.2007

1891,6 1880 1870 1860 1850 1840 1830 1820 1815,4

0,2

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

32

34

35,5

Raman Shift / cm-1

Int

2 min

4 min

1 min

Maleic Anhydride

Ambient

b)

c)

a)

a)

b)

c)___

___

___

1842,96

1858,76

1842,96

1858,76


- 53 -

From spectrum of mixture MA/SHP (molar ratio 1:0.25) we can observe new bands at 3116,

1854, 1840, 1783 cm-1

too, same bands are having lower intensity comparing with of mixture

MA/SHP (molar ratio 1:0.1). In spectrum of mixture MA/SHP (molar ratio 1:0.5) the band

around 3060-3050 cm-1

which is associated with =C-H stretch of MA decrease in its intensity and

a new saturated C-H stretch band around 2940 cm-1

starts to appear. A band at 1851 cm-1

is still

present what probably mean, that in the same time formation of an anhydride is taken. Also the

band which is associated with out of plane deformation of =C-H of MA (around 3060-3050 cm-1

)

still remains.

Figure 5.14: Raman spectra of MA/SHP mixtures in different molar ratio heated at T= 150 °C

for 4 min.

3500,0 3000 2000 1500 1000 500 100,0 Raman Shift / cm-1

Int

1 : 1

1 : 2

1 : 0.5

1 : 0.25

1 : 0.1

3059,16 3116,41

1840,47

1854,72 1783,50

1720,83 1700,89 1635,38

1589,80 1567,01

1330,58 1219,49 1017,24

863,41

638,38 951,72

3059,16

1589,80 1567,01

1393,25

1330,58 1219,49 1017,24

863,41

638,38 951,72

1851,87

1723,68 1700,89

3059,16 1393,25

863,41

638,38

1851,87 1706,59 1643,92

3059,16 1393,25

1706,59

1643,92

1618,29 2938,93

1208,09 1088,45

866,26

926,08

3047,70

1393,25

1706,59

1618,29

2938,93

1208,09 1088,45

1062,81

866,26

926,08

1649,62


- 54 -

Spectrum of mixture in 1:1 molar ratio does not show any peaks related to anhydride, band

associated with saturated C-H stretch appear, band around 3060- 3050 cm-1

associated with =C-H

stretch decrease and band at 863 cm-1

due to out of plane deformation of =C-H of MA decrease.

Raman spectra of mixtures in same molar ratio and heated at elevated temperature for 5 minutes

(Figure 5.15) show similar trend as spectra of mixtures in Figure 5.14.

Figure 5.15: Raman spectra of MA/SHP mixtures in different molar ratio heated at 150 °C for 5

min.

When the time of heating was reduced to 3 minutes, Raman spectra of heated mixtures show less

intensive similar changes, but trend of changes is slower (Figure 5.16).

3500,0 3000 2000 1500 1000 500 100,0 Raman Shift / cm-1

Int

1 : 0.1

1 : 0.25

1 : 0.5

1 : 1

1 : 2

3059,16 3116,41

3179,38

1849,02

1777,81

1723,68 1700,89

1635,38

1589,80

1567,01

1330,58 1219,49 1065,66

1017,24

863,41 635,53

2400,76

3059,16

3116,41

3179,38

1849,02 1777,81

1723,68

1700,89

1635,38

1589,80 1567,01

1330,58

1219,49

1017,24

863,41

635,53 2400,76

863,41

800,74 2938,93

3053,43

1706,59

1649,62

1618,29

1390,40

1210,94 1088,45

1045,72 923,23

1151,12

1065,66

863,41 800,74 2938,93

3053,43

1706,59 1649,62

1618,29

1390,40

1210,94

1159,67

1088,45 923,23

1849,02 1723,68

863,41

800,74

635,53 2400,76

2938,93

3053,43 1641,07 1034,33

923,23 1151,12 1210,94

1396,10


- 55 -

Figure 5.16: Raman spectra of MA/SHP mixtures in different molar ratio heated at T= 150 °C,

tcuring = 3 min.

Raman spectroscopy data shows that reaction depends on the relative amount of SHP present.

When MA/SHP mixture in molar ration 1: 0.5 was heated, formation of the band at around 3060-

3050 cm-1

(=C-H stretch of MA) decreases in its intensity and a new saturated C-H stretch band

around 2940 cm-1

start to appear. A band at 1851 cm-1

is still present, what probably mean, that in

the same time formation of an anhydride occurred. Data also shows that small amount of a

catalyst already precedes anhydride formation and that formation of an anhydride happens before

the additional reaction of SHP on double bond of maleic anhydride.

3500,0 3000 2000 1500 1000 500 100,0 Raman Shift / cm-1

Int

1 : 0.1

1 : 0.25

1 : 0.5

1 : 1

1 : 2

3059,16 2429,38

2452,29

1720,83 1700,89

1635,38

1586,95

1567,01

1330,58

866,26

1216,64

3059,16 2429,38

2452,29

1720,83

1743,62 1851,87

1700,89 1661,01

1635,38

1586,95

1567,01

1330,58 866,26

1216,64

3064,88 2429,38

2452,29

1743,62

1851,87

1661,01

1635,38 866,26

1216,64

3053,43 2383,58

866,26

1216,64 1088,45 1390,40

1615,44

1649,62

1703,74

2933,20

923,23 1042,87

1151,12

3053,43 2366,41 866,26 1216,64

1088,45

1390,40

1615,44

1649,62

1703,74

2933,20

923,23 1159,67

1062,81


- 56 -

When not enough SHP is added, anhydride of maleic acid is formed (Raman spectra in Fig. 5.15),

so SHP acts as a catalyst for anhydride formation (Fig. 5.17).

CH

CH C

C

O

O

OH

OH C

O

O

O

CCH2

CH2dH

Figure 5.17: Formation of maleic anhydride at elevated temperature.

We can conclude that MA forms anhydride at elevated temperature (150 °C, t = 3 min). When

catalyst SHP is added to MA, the addition of SHP on double C=C bond of MA started, the

proposed reaction is shown in Figure 5.18.

CH

CHC

C

O

O

OH

OH

PH

O

H

O Na+

CH

CH C

C

O

O

OH

OH

PCH

C

O

OH

O

OHC

O

O

CH

CH2CH

2C

C

O

OH

O

OH

Na+

+dH

+

Figure 5.18: Addition of SHP on double C=C bond of MA at elevated temperature.

When molar ratio of MA/SHP is 1:0.5 or higher there is enough SHP in the mixture and reaction

starts (spectra in Fig. 5.14).

5.2.5 Addition of Na2HPO3

For comparison purposes mixtures of MA with catalyst disodium hydrogen phosphite (DSHP)

were prepared (samples named as S36-S50, Table 4.2). Because of its structure (Fig. 5.19) DSHP

is not able to add on double C=C bond of MA. This can be proved with Raman spectroscopy.

P

OH

O ONa+

Na+_ _

Figure 5.19: Disodium hydrogen phosphite (DSHP).


- 57 -

Figure 5.20 shows Raman spectra of MA/DSHP mixtures heated at elevated temperature for 4

minutes. From spectra is possible to observe that changes regarding disappearing of C=C bond of

MA did not occurred. Band for =C-H (around 3060-3050) remains even when the mixture

MA/DSHP in molar ratio 1:2 is heated to 150 °C for 4 minutes (Fig. 5.20) or for 5 minutes (Fig.

5.21). The similar results are obtained if MA/DSHP mixtures were heated for 3 minutes at

elevated temperatures (Fig. 5.22).


for 4 min.


- 58 -


for 5 min.


for 3 min.

3500,0 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 600 400 200 100,0

Raman Shift / cm-1

Int

1 : 0,1

1 : 0,25

1 : 0,5

1 : 1

1 : 2

3500,0 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 600 400 200 100,0

Raman Shift / cm-1

Int

1 : 0,1

1 : 0,25

1 : 0,5

1 : 1

1 : 2


- 59 -

5.3 FT-IR analysis

Figures from 5.23 to 5.26 are showing FT- IR spectra of maleic acid (MA), maleic anhydride

(MAnh), and catalysts, which were used in our research; sodium hydroxyphosphinite (SHP), and

disodium hydrate phosphite (DSHP).

Figure 5.23: FT-IR Spectrum of maleic acid (MA).

In IR spectrum of MA (Figure 5.23) we can see the band at 1703 cm-1

which is assigned to C= O

group. In IR spectrum of Maleic anhydride (Figure 5.24) the bands at 1855 and 1774 cm-1

can be

assigned to the anhydride.

4000,0 3600 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 650,0

6,8

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

99,9

cm-1

%T

3058,912871,89

2686,12

2605,33

2506,09

2362,95

2163,66

1890,73

1703,09

1633,62

1584,20

1561,22

1459,21

1431,62 1261,09

1219,90

984,53

914,58 786,14


- 60 -

Figure 5.24: FT-IR Spectrum of maleic anhydride (MAnh).

Figure 5.25: FT-IR Spectrum of sodium hydroxyphosphinite (SHP).

4000,0 3600 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 650,0

5,9

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

101,2

cm-1

%T

3590,62 3189,03

3124,85

2173,52

1986,57

1932,54

1855,83

1800,95

1774,32

1752,70

1631,61

1592,92

1566,43

1459,27

1433,95

1398,87

1289,62

1267,82

1240,49

1115,57

1056,43

957,92

892,62

871,58

767,11

691,70

1706,60

4000,0 3600 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 650,0

18,1

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

105,2

cm-1

%T

3256,092349,91

2317,96

2280,87

1979,97

1671,06

1227,86

1181,58

1142,75

1088,19

1041,53

803,24


- 61 -

Figure 5.26: FT-IR Spectrum of disodium hydrate phosphite (DSHP).

Date: 26.1.2009

4000,0 3000 2000 1500 1000 650,0

26,4

30

35

40

45

50

55

60

65

70

75

80

85

90

95

101,4

cm-1

%T

3236,4

2341,9

2300,0

2070,8

1685,9

1228,8

1182,5

1087,0

1035,4 972,6

913,1

1718,0


- 62 -

5.3.1 The influence of temperature of heating

FT-IR analysis of mixtures MA/SHP, maleic acid and catalyst SHP at room temperature where

done. In Fig. 5.27 we can see FT-IR spectra of MA, SHP and mixture MA/SHP which spectrum

was collected after one week.

Figure 5.27: FT-IR spectra of MA/SHP mixture (1:1 molar ratio), MA and SHP at ambient

temperature.

We can conclude that after some time we cannot detect any reaction between MA and SHP at

room temperature with FT-IR measurements.

4000,0 3000 2000 1500 1000 650,0 cm-1

%T

Mixture MA/SHP(1:1)

MA

SHP

2317,46

2349,20

2380,95

2281,74

802,64 1042,51

1088,10

1141,62 1155,50

1181,27

1211,01

1228,85

3059,52

1702,64 1561,89

1583,70

1631,27

1460,79

1433,03 1262,55

1329,95

1218,94

1022,68

983,03 947,35

913,65 860,13 786,78

2317,46 2428,57

2452,38

1702,64

1730,39

1676,87 1657,04

1633,25

1583,70 1561,89

1450,88

1419,16 1361,67

1314,09

1240,74

1209,03

1109,91 1054,40

1008,81

987,00 967,18

860,13

828,41

800,66

786,78


- 63 -

MA/SHP mixtures in molar ratio 1:1 were heated to 120 ºC, 140 ºC, and 160 ºC for 2 minutes

(samples S8-S11, Table 4.1) to see how the temperature influence on addition of SHP on double

C=C bond of maleic acid.

From spectra in Fig. 5.28 we can observe, that when a mixture was heated at 160 ºC for 2

minutes band at 2354 cm-1

related with P-H bond starts to decrease. A band related with

anhydride formation is detectable; a shoulder at 1772 cm-1

could be assigned to it.


temperatures; a) T= 120 ºC, b) T= 140 ºC, c) T= 160 ºC for 2 minutes.

Date: 21.5.2007

4000,0 3000 2000 1500 1000 650,0

17,1

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

102,5

cm-1

%T

___ c)

___ a)

___ b)

1704,21

2354,43

1772,83

2354,43


- 64 -

When MA/SHP mixtures where heated for 3 minutes instead of 2, we obtain better results (Fig.

5.29). A band at 2354 cm-1

related with P-H bond starts decrease strongly and a band which is

related with formation of anhydride at 1777 cm-1

was strongly detectable.


temperatures (a) T= 140 ºC, b) T= 150 ºC, c) T= 160 ºC) for 3 minutes.

IR spectra are showing, that anhydride is formed at higher temperature compared to Raman

spectroscopy data.

Date: 21.5.2007

4000,0 3000 2000 1500 1000 650,0

17,4

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

101,9

cm-1

%T

___ b)

___ a)

___ c)

1701,68

1701,681777,52

2359,49

2359,49


- 65 -

5.3.2 The influence of time of heating

To see how the time of heating influence on reaction, mixtures prepared mol ratios and heated at

elevated temperature as described in Table 4.1 (samples from S16 to S20) were analyzed with

FT-IR.

We can observe increasing of a new band at 1779 cm-1

, when the mixture was heated for 4

minutes at elevated temperature, which can be assigned to anhydride formation (Fig. 5.30).

Figure 5.30: FT IR Spectra of MA/SHP mixtures (1:1 molar ratio) heated at 150 ºC for different

times (t= 0.5, 1, 2, 4 and 6 minutes).

As conclusion we can say, that if mixture is heated at 150 °C for 4 minutes, formation of

anhydride start to appear.

Date: 9.12.2008

4000,0 3000 2000 1500 1000 650,0

cm-1

%T

4 min

6 min

2 min

1 min

0,5 min

2452,68

2428,45

2360,50

1705,82

1677,51

1656,32

1578,17

1451,45

1359,56

1313,30

1211,411110,34

1052,06

1009,78

967,36

863,51

827,67

799,73

756,63

661,23

3511,01

3328,07

2360,05

1698,20

1655,15

1576,22

1508,17

1451,96

1363,21

1145,71

1118,10

1011,55

966,69

858,79

809,31

735,28

659,58

3510,74

3335,38

2361,64

1698,26

1624,73

1577,34

1541,97

1508,381395,84

1364,03

1139,791031,01 859,50

812,98

769,66

1779,95

3505,123345,05

2382,76

1701,51

1625,04

1577,96

1396,16

1364,72

1143,461035,11 860,101779,95

3505,04

3327,23

3227,47

2360,58

1677,70

1655,35

1571,30

1508,42

1452,88

1394,72

1364,10

1171,48

1118,31

1010,96

966,60

902,41

858,34

806,55

735,95

659,31

1700,66


- 66 -

5.3.3 Heating of MA at 150 ºC for different times without adding a

catalyst

Heating of MA at elevated temperature for different times without adding a catalyst was

performed (samples: S2-S6, Table 4.1).

FT-IR spectra of maleic acid, when heated, do not show the same trend as it was observed with

FT-Raman analysis. With FT-IR analysis we cannot proof the formation of anhydride even if MA

is heated for 8 minutes. From Figure 5.31 it is clearly to see that bands associated with anhydride

formation do not appear.

Figure 5.31: FT-IR spectra of MA, MAnh at ambient temperature and MA heated at 150 ºC for 8

minutes.

Raman analysis of MA heated at elevated temperature gave us much better results. It was

possible to see that after maleic acid was heated at elevated temperature for 6 minutes new bands

at 3188, 3131 and 3122 cm-1

appear, which can be assigned with bands of C=C stretch of maleic

4000,0 3000 2000 1500 1000 650,0 cm-1

%T

MA at 150 C for 8 minutes

MA

MAnh

3058,92 2686,56 2606,01

2506,61 2361,25

2163,29

1703,09

1634,35

1584,33 1560,73

1459,19 1431,59 1261,96

1219,87

986,61

914,90

860,76

786,42

3058,91 2686,12 2605,33

2506,09 2362,95

2163,66

1703,09

1633,62

1584,20 1561,22

1459,21 1431,62 1261,09

1219,90

984,53

914,58

860,35

786,14

3189,03

3124,85

2173,52 1986,57 1932,54

1855,83 1800,95

1774,32 1752,70

1631,61

1592,92

1459,27

1398,87

1289,62 1267,82

1240,49

1115,57

1056,43

957,92

892,62

871,58

767,11

691,70


- 67 -

anhydride and that when MA was heated at 150 °C for 6 minutes without SHP the formation of

anhydride occurred. FT-IR spectroscopy analysis was not appropriate method for this analysis.

5.3.4 The influence of molar ratio of MA and SHP

In the next step we studied the influence of molar ratio between MA and catalyst SHP on

addition reaction. MA/SHP mixtures in different molar ratios were prepared as presented in Table

4.1 (samples: S21-S35).

Figures 5.32 and 5.33 show collected spectra of MA/SHP mixtures when heated for 4 minutes at

150 °C. Figure 5.32 shows spectra of MA/SHP mixtures in region from 1936 till 1347 cm-1

. From

spectra of MA/SHP mixtures in 1:0.1, 1:0.25 and 1:0.5 molar ratio is possible to observe bands or

shoulders associated with formation of an anhydride (the strongest band is at 1774 cm-1

).

Figure 5.32: FT-IR spectra of MA/SHP mixtures in different molar ratio heated at 150 °C, for 4

min in region from 1936 to 1347 cm-1

.

1936,6 1900 1850 1800 1750 1700 1650 1600 1550 1500 1450 1400 1347,8 38,6

40

45

50

55

60

65

70

75

80

85

87,8

cm-1

%T

___

___

___

1 : 0,25

1 : 0,5

1 : 0,1

1775

1732,85

1748,75

1847,62

1703,54


- 68 -

Spectra of MA/SHP mixtures in molar ratio 1:1 and 1:2 does not show the same bands or

shoulders (Figure 5.33).



.

Prepared mixtures were heated also for 5 minutes at elevated temperature. Figure 5.34 shows

spectra of MA/SHP mixtures in region from 1901 to 1650 cm-1

. Spectra of MA/SHP mixtures in

1:0.1, 1:0.25 and 1:0.5 molar ratio better show bands or shoulders associated with formation of

an anhydride (the strongest band is at 1774 cm-1

). Spectra of MA/SHP mixtures in molar ratio 1:1

and 1:2 does not show the same bands or shoulders (Figure 5.34).

2062,0 1950 1900 1850 1800 1750 1700 1650 1600 1550 1500 1450 1390,3 31,9

35

40

45

50

55

60

65

70

75

80

85

90

95

98,7

cm-1

%T

___

___

___

1:0.5

1:1

1:2

1774,05


- 69 -



.

Increasing of time of heating gave us better results. Compare to FT-Raman spectroscopy results,

FT-IR analysis gave us similar results, but changes were not strongly detected as those obtained

by Raman spectroscopy analysis. When a mixture of MA (1mol) with small amounts of SHP (0.1

or 0.25 mol) was heated at elevated temperature for 4 or 5 minutes, formation of an anhydride

starts. That means that SHP is acting in the mixture as a catalyst.

5.3.5 Addition of Na2HPO3

Mixture with MA and another catalyst disodium hydrate phosphite (DSHP) were prepared as

mentioned at elevated temperature for different times (samples from S36 to S50, Table 4.2). FT-

IR analyses of prepared mixtures were done.

Figure 5.35 shows FT-IR spectra of MA/DSHP mixtures heated at 150 ºC for 4 minutes.

1901,2 1880 1860 1840 1820 1800 1780 1760 1740 1720 1700 1680 1650,0 25,0

30

35

40

45

50

55

60

65

70

75

80

85

88,9

cm-1

%T

1:0.1 ___

___

___

___

___ 1:0.5

1:0.25

1:1

1:2

1856,31

1777,28

1703,14


- 70 -

Figure 5.35: FT-IR spectra of MA/DSHP mixtures in different molar ratio heated at 150 °C for 4

min.

No new bands related with formation of anhydride appear. FT-IR spectra of heated mixtures for

longer or shorter time (3 and 5 min) did not gave us better results, because of that these spectra

will not be presented. Also with Raman spectroscopy analysis we did not obtained any new

bands, probably this is associated with the structure of DSHP.

4000,0 3000 2000 1500 1000 650,0 cm-1

%T

1:0.1

1:0.25

1:0.5

1:1

1:2

1704,62 1635,24

1575,77 1458,81 1431,05

1395,37

1369,60

1218,94 1173,34

858,14

901,76 810,57 1070,26

1704,62 1635,24

1575,77 1218,94 1173,34

858,14

901,76 810,57

1369,60 1395,37

1090,08 1062,33

1704,62 1635,24

1575,77 1218,94

1173,34

858,14

901,76

810,57 1369,60 1395,37

1090,08

1062,33

1704,62 1635,24

1561,89

1458,81 1431,05

1395,37

1369,60

1218,94 1173,34

858,14

901,76 1264,53

1704,62 1635,24

1561,89 1458,81 1431,05

1395,37 1369,60

1218,94

1173,34

858,14

901,76 1070,26 1264,53


- 71 -

5.4 Treatment of cellulose fabrics with maleic acid

5.4.1 Treatment of cellulose fabrics with maleic (MA) acid with addition

of SHP or DSHP catalyst

Solutions of MA/ SHP and MA/DSPH in different mole ratios as shown in Tables 4.3 and 4.4

were prepared. Desized, scoured, bleached and mercerized cotton fabric was padded to give wet

pick up of 95 to 105%. Fabrics were suspended in a forced draught oven and predried at 110 ºC

for 10 minutes. Then fabrics were cured in Werner Mattis thermo fixation equipment at 165 ºC

for 3 minutes. All samples were rinsed after the curing. Treated fabrics were also immersed in to

the 0.1 M solution of NaOH and dried (FT-IR analysis). On all treated cotton samples wrinkle

recovery angle was measured.

5.4.1.1 FT-IR analysis

Figure 5.35 shows FT-IR spectra of a sample named S54; a) treated cotton fabric with MA/SHP

mol. r. 1:0.5, cured at 165 °C for 3minutes and b) treated cotton with MA/SHP molar ratio 1:0.5,

cured at 165 °C for 3 minutes (samples were later treated with alkaline solution of NaOH, cotton

fabric spectra was subtracted) in the range 1788 to 1522 cm-1

, spectra were normalized at 1314

cm-1

.

The post treatment of finished fabrics in alkaline solution converts the acid to carboxylate anion,

which absorbs at 1570 cm-1

respectively, while the ester carbonyl is left unchanged. This method

permits characterisation of ester crosslinks in cotton fabrics by infrared spectroscopy. In

polycarboxylic acid-finished cotton fabrics the carbonyls retained exist in three forms: ester,

carboxylic acid and carboxylate anion. In the case of cotton cellulose esterified with a

polycarboxyic acid containing three or more carboxylic groups, all three forms of carbonyls

could be present. In infrared spectra the band due to an ester carbonyl group appears around 1735

to 1715 cm-1

, and the band due to a carboxylic acid carbonyl group appears in the same region.

Treatment of polycarboxylic acid-finished cotton fabrics with a sodium hydroxide solution

converts the acid to the carboxylate anion. The overlapping of bands for carboxylic acid groups

and ester groups is thus avoided. The carbonyl band intensity ratio (1719/ 1571 cm-1

) can be used

as another parameter to compare the different degrees of ester crosslinking fabrics.


- 72 -

In FT-IR Spectrum of alkaline post treated MA/SHP finished cotton fabric (sample S54), a band

at 1719 cm-1

associated with ester bonds decreased while the intensity of band regarding

carboxylate region at 1571 cm-1

increased (Figure 5.36).

Figure 5.36: FT-IR spectra of sample S54 in the range from 1788 to 1522 cm-1

:

a) Treated cotton with MA/SHP mol. ratio 1:0.5, cured at 165 °C for 3 min and

b) Treated cotton with MA/SHP mol. ratio 1:0.5, cured at 165 °C for 3 min, sample is

treated later with alkaline solution of NaOH, spectra were normalized at 1314 cm-1

and

cotton fabric spectrum was subtracted.

Polycarboxylic acid esterifies cotton cellulose by first forming a 5-membered cyclic anhydride as

a reactive intermediate. Therefore in our system only one of the two carboxyl groups of MA is

able to esterify cotton cellulose. MA alone is not able to crosslink cellulose. So the probable

mechanism for MA to crosslink cotton cellulose is in the presence of SHP on cotton. A

1788,1 1760 1740 1720 1700 1680 1660 1640 1620 1600 1580 1560 1540 1522,7 -0,008

0,00

0,01

0,02

0,03

0,04

0,05

0,06

0,07

0,08

0,09

0,10

0,11

0,12

0,13

0,14

0,15

0,164

cm-1

A

a)

b)

1719,8

1719,8

1571,2


- 73 -

phosphorus-containing crosslinkage between two cotton cellulose molecules is obtained and

carboxylate anions or carboxylic acid groups remain free (Fig. 5.37).

CellOCCH2

CellOCCH2

CH

O

P

COOH

OO

CH COOH

O

CellOCCH2

CellOCCH2

CH

O

P

COO

OO

CH COO

O

alkalinetreatment

_

Na+

_

Na+

Figure 5.37: Conversion of carboxylic acid groups into carboxylate anions.

FT-IR spectra comparison (Figure 5.36) was presented only for sample S54. In Figure 5.38 the

ester carbonyl bond intensity of all cotton fabrics treated with solutions of MA/SHP or

MA/DSHP in different molar ratios from 1:0.05 to 1:1 is presented. Using SHP as a catalyst,

maleic acid was crosslinked more efficiently compare to the crosslinking system when DSHP

was used; especially when higher molar ratios are used. This proved that SHP is more efficient

catalyst compare to DSHP.

Figure 5.38: The ester carbonyl bond intensities’ of treated cotton fabrics with solutions of

MA/SHP (samples: S51-S55) or MA/DSHP (samples: S56-S60).

0,05

0,1

0,15

0,2

0,25

0,3

0,05 0,12 0,25 0,50 1,00

n (catalyst)

Carb

on

yl B

on

d Ite

nsit

y

NaH2PO2

Na2HPO3


- 74 -

5.4.1.2 FT-Raman analysis

Figure 5.39 shows FT-Raman spectra of a treated cotton fabric with MA/SHP (molar ratio 1:0.5),

cured at 165 °C for 3 minutes (sample named as S54, Table 4.3) and of untreated cotton.

Figure 5.39: Raman spectra of untreated cotton fabric marked as a) and spectrum of the treated

cotton sample S54 marked as b).

Due to the overlapping of a peak for single C-C bond (around 2940 cm-1

) with hydroxyl groups

of cellulose we are not able to prove is the appearance of it. The peak for double bond at around

3050-3060 cm-1

is not present on spectrum of treated sample S54 in Fig. 5.39; this can indicate

that addition to double bond proceeded.

3500,0 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 600 400 200 100,0

0,000

0,05

0,10

0,15

0,20

0,25

0,30

0,35

0,40

0,45

0,50

0,55

0,60

0,65

0,70

0,75

0,80

0,858

Raman Shift / cm-1

Int

b)___

a)___

2896,6

1727,21599,8

1476,9

1461,2

1378,5

1338,3

1293,6

1150,5

1119,2

1096,9

898,0

518,0

459,8

437,5

381,6


- 75 -

5.4.1.3 Wrinkle recovery angle (WRA)

Crosslinking cotton cellulose increases wrinkle resistance (WRA) compare to untreated fabrics.

WRA depends on the amount of crosslinking places formed in the treated cotton fabric.

The conditioned WRA of the cotton fabrics treated as presented in Tables 4.3 and 4.4 are

presented in Figure 5.40. The WRA of cotton fabric without any treatment (control) is 70º and

increases to 92º when fabric is treated with solution of MA/SHP in 1:0.5 mole ratio. When the

cotton fabric is treated with solution of MA and DSHP, WRA of the treated fabrics does not

increase so much, the highest value is 83º.

Figure 5.40: Conditioned WRA of cotton fabrics treated by solutions of MA/SHP (samples: S51-

S55) and MA/DSHP (samples: S56-S60) in different mole ratios, cured at 165 ºC for 3 min and

rinsed, versus catalysts moles in treating baths.

From wrinkle recovery angle and FT-IR ester carbonyl bond intensity (Figure 5.38) we can

conclude that the treatment of cotton fabrics was successful and reaction between maleic acid and

SHP as catalyst and cellulose occurred at elevated temperature and time. Two reactions occurs in

one step: first the esterification of hydroxyl groups of cellulose occurs via anhydride formation,

when maleic acid is linked to hydroxyl group’s further crosslinking via addition of SPI on carbon

double bond occur. The second reaction, the addition on double bond, increases the efficiency of

crosslinking significantly.

WRA after 30 min

70

75

80

85

90

95

0.05 0.12 0.25 0,5 1

n (Catalyst)

WR

A (

°)

NaH2PO2

Na2HPO3


- 76 -

5.4.2 Determination of crosslinking efficiency by ICP- AES

Determination of crosslinking efficiency of MA/SPH systems on cotton material was performed.

The unwoven cotton was immersed in solutions containing MA and SHP in different mole ratios,

dried and cured as presented in Table 4.5 (samples: S61-S64).

The phosphorus concentrations of cotton samples treated with MA and SHP in different mole

ratios and subjected to 1 home laundering are shown in Figure 5.41.

Figure 5.41: The phosphorus concentration of the cotton fabric treated with MA/SHP at different

mole ratios and cured at 170 °C (after 1 home laundering) versus SHP moles in treating baths.

The phosphorus concentration of the fabric increases as the concentration of SHP in treating

baths is increased, and it reaches the maximum (P=0.57%) when MA to SHP mole ratio of 1:0.5

was used. Thus, the data shows that the crosslinking reaction between maleic acid and SHP and

cellulose occurred and that mechanism of MA and SHP with cotton cellulose is that two

esterified molecules of MA react with one molecule of SHP which leads to a crosslinked

structure.

0,00

0,10

0,20

0,30

0,40

0,50

0,60

0,70

0,00 0,10 0,20 0,30 0,40 0,50 0,60 0,70

n (SHP)

P%

on

th

e f

ab

ric


- 77 -

6 CONCLUSIONS

In this work unsaturated dicarboxylic acid as crosslinking system in textile finishing have been

studied; first by studies of chemical reactions of our system with Raman and Infrared

spectroscopy and second by the efficiency of crosslinking on cotton cellulose using Infrared

spectroscopy, Wrinkle Recovery angle measurements and for determination of phosphorus by

Inductively coupled plasma atomic spectroscopy. The results of analytical methods for

characterization of crosslinking efficiency have been compared.

Raman and Infrared spectroscopy analysis of prepared mixtures revealed reactions between MA

and SHP in order shown in Figure 6.1. Formation of a 5-membered cyclic anhydride as a reactive

intermediate was observed already if SHP was added in small concentrations when mixture was

heated for 4 minutes at 150 °C. Catalyst SHP also influence the formation of the anhydride with

reducing the time of heating when comparing results of MA heated alone. When the SHP

concentration is increased so that ratio between MA and SHP is 1: 0.5, addition of SHP on the

double bond of MA started. Introducing another catalyst instead of SHP, DSHP which is not

capable the addition to double carbon bond, shows that reaction of addition on double bond of

MA did not occur. So the only suitable catalyst for this research was SHP. The efficiency of

crosslinking on cotton cellulose was studied too.

The data demonstrate that in the presence of MA, significant amount of phosphorus is bound to

cotton fabric when the temperature is increased to 150 °C. Therefore, a possible mechanism for

the majority of phosphorus being bound to the cotton fabric when it is treated with the

combination of MA and SHP is an addition reaction of hydroxyphosphinite ion to the MA on

cotton as shown in Figure 6.1. MA first esterifies cotton cellulose to form I through the

formation of a cyclic anhydride intermediate. I further reacts with hydroxyphosphinite ion to

form II, thus bonding phosphorus to cotton cellulose.


- 78 -

Heating

OC

C C

CO O

H H

C C

C

O

HO

H

C

O

OH

H

I

OHCell+

OC

C C

CO O

H H

C

O

HO

C C

C

O

O Cell

H H

Cellulose

II

CellC

O

C

H

PO

O

H

C

H

H

C

O

OHOH P

O

O

HI +

I

C

O

HO

C C

C

O

O Cell

H H

O C

O

C

H

H

C

H

C

P C C C

O

O H

C

H

H

O

OOH

O

OH

O

Cell Cell

CellC

O

C

H

PO

O

H

C

H

H

C

O

OHO +

II

III

Figure 6.1: Reaction scheme.

The increased WRA of the cotton fabric treated with MA/SHP at elevated temperatures indicates

that crosslinking takes place on the treated cotton fabric. In chapter 2.4.2 is written that

polycarboxylic acid esterifies cotton cellulose by first forming a 5-membered cyclic anhydride as

a reactive intermediate. Therefore, only one of the two carboxyl groups of MA is able to esterify

cotton cellulose. Consequently, MA is not able to crosslink cellulose and imparts wrinkle

resistance to cotton fabric by itself as shown in Figure 5.40. The probable mechanism for MA to

crosslink cotton cellulose in the presence of SHP on cotton is shown in Figure 6.1, in which the

esterification product of MA with cotton cellulose (marked as I) reacts with the addition product


- 79 -

of SHP with the esterification product of MA on cotton (marked as II) to form a phosphorus-

containing crosslinkage between two cotton cellulose molecules (marked as III).

The phosphorus concentration of the treated fabric reaches the maximum when the SHP

concentration is increased MA to SHP mole ratio of 1: 0.5. Thus, the data supports the

crosslinking reaction mechanism of MA and SHP with cotton cellulose shown in Figure 6.1, in

which two molecules of MA react with one molecule of hydroxyphosphinite ion.

With the ester carbonyl band intensities of cotton fabrics treated with MA and SHP, it is seen that

the ester carbonyl band intensity increases linearly with the SHP concentration and this trend is

parallel to the rise in phosphorus concentration on cotton as a consequence of the increasing SHP

concentration. Thus, the data presented here again confirm that hydroxyphosphinite ion of

sodium hydroxyphosphinite is bound to the cotton fabric by its reaction with the MA esterified to

cotton as demonstrated in Figure 6.1.


- 80 -

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3. BADULESCU, Roxana, VIVOD, Vera, JAUŠOVEC, Darja, VONČINA, Bojana. Grafting of

ethylcellulose microcapsules onto cotton fibres. Carbohydr. polym.. [Print ed.], 2008, vol. 71, iss.

1, str. 85-91. http://dx.doi.org/j.carbpol.2007.05.028. [COBISS.SI-ID 11812118]

1.08 Objavljeni znanstveni prispevek na konferenci

4. MAJCEN, Nataša, VONČINA, Bojana, VIVOD, Vera, MAJCEN LE MARECHAL, Alenka.

Surface modification of natural fibres by using [beta]-cyclodextrin derivative. V: Fibre-grade

polymers, chemical fibres and special textiles : proceedings. Maribor: Faculty of Mechanical

Engineering, Textile Department, 2003, [4] f. [COBISS.SI-ID 8198678]

5. MAJCEN, Nataša, VONČINA, Bojana, VIVOD, Vera, MAJCEN LE MARECHAL, Alenka,

BRODNJAK-VONČINA, Darinka. Obdelava celuloznih vlaken za naravnimi in modoficiranimi

ciklodekstrini. V: GLAVIČ, Peter (ur.), BRODNJAK-VONČINA, Darinka (ur.). Slovenski

kemijski dnevi, Maribor, 25. in 26. september 2003. Zbornik referatov s posvetovanja. Maribor:

FKKT, 2003, 6 f. [COBISS.SI-ID 8260118]

http://dx.doi.org/10.1016/j.dyepig.2006.04.013

http://cobiss.izum.si/scripts/cobiss?command=DISPLAY&base=COBIB&RID=10533142


http://dx.doi.org/j.carbpol.2007.05.028





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6. PERRIN AKCAKOCA, E., VONČINA, Bojana, OZGUNEY, Arif T., KARAHAN, Aylin,

VIVOD, Vera. Crosslinking of [beta]-CD on cotton using N-methylol-acrylamide and a fixation

agent based on aminoplast. V: MAJCEN LE MARECHAL, Alenka (ur.), STJEPANOVIĆ, Zoran

(ur.), KOKOL, Vanja (ur.), ŢUNIČ-LOJEN, Darja (ur.), FAKIN, Darinka (ur.), FUŢIR BAUER,

Gabrijela (ur.), ZIMŠEK, Danijel (ur.), KRIŢANEC, Boštjan (ur.), VOLMAJER, Julija (ur.),

VONČINA, Bojana (ur.). 5th World Textile Conference AUTEX 2005, 27-29 June 2005,

Portoroţ, Slovenia. Proceedings. Maribor: Faculty of Mechanical Engineering, Department of

Textiles, 2005, str. 207-210. [COBISS.SI-ID 9697302]

7. VONČINA, Bojana, VIVOD, Vera, ŢAJDELA, Boštjana. [Beta]-cyclodextrin in

polyacrilonitrile dyeing. V: SIMONČIČ, Barbara (ur.), MOŢINA, Klementina (ur.), JELER,

Slava (ur.), DEMŠAR, Andrej (ur.). 37th International Symposium on Novelties in Textiles [and]

2nd International Symposium on Novelties in Graphics [and] 7th International Symposium of

SCA: Colors of National Symbols, Ljubljana, Slovenia, 15-17 June 2006. Book of proceedings.

Ljubljana: Faculty of Natural Sciences and Engineering, Department of Textiles, 2006, 5 f.

[COBISS.SI-ID 11463702]

8. BADULESCU, Roxana, VIVOD, Vera, JAUŠOVEC, Darja, VONČINA, Bojana. Treatment

of cotton fabrics with ethyl cellulose microcapsules. V: International Conference and Exhibition

on Healthcare and Medical Textiles, 16-18 July 2007, Bolton University, UK. MEDTEX 07 :

digital book. Bolton: Centre for Materials Research and Innovation, 2007, 8 str. [COBISS.SI-ID

11493910]

9. JAUŠOVEC, Darja, VONČINA, Bojana, BLACKBURN, Richard S., ANGELESCU, D.,

LINDMAN, B., VIVOD, Vera. Biodegradability of cellulose. V: Textile processing : state of the

art & future development. Cairo: National Research Centre, 2008, str. 155-160. [COBISS.SI-ID

12218646]

1.12 Objavljeni povzetek znanstvenega prispevka na konferenci

10. VONČINA, Bojana, VIVOD, Vera, KREŠEVIČ VRAZ, Silva, ZUPANC, Maja, CHEN,

Wen-Tung. Molecular encapsulation of textiles for slow release : invited lecture. V: 2007

International Forum on Biomedical Textile Materials & Annula Meeting of 111Project,

Shanghai, P.R. China, 30th May - 2nd June 2007. Abstracts & program book. [S.l.: s.n.], 2007,

str. 37-38. [COBISS.SI-ID 11752470]

11. JAUŠOVEC, Darja, VONČINA, Bojana, BLACKBURN, Richard S., VIVOD, Vera.

Influence of antimicrobial agents on cellulose biodegradation. V: 5th Central Europen

Conference Fibre-Grade Polymers, Chemical Fibres and Special Textiles, 5-8 September 2007,

Kraków, Poland. CEC 2007 : programme and abstracts. [S.l.: s.n.], 2007, str. 45-47.

[COBISS.SI-ID 11628822]

12. VIVOD, Vera, VONČINA, Bojana, JAUŠOVEC, Darja, HUNJADI, Suzana, WU, X.,

YANG, C. Q. Investigation of the chemical reactions of maleic acid with sodium hypophosphite

and its uses as a crosslinking system for cotton. V: 5th Central Europen Conference Fibre-Grade








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Polymers, Chemical Fibres and Special Textiles, 5-8 September 2007, Kraków, Poland. CEC

2007 : programme and abstracts. [S.l.: s.n.], 2007, str. 48-49. [COBISS.SI-ID 11629846]

13. VONČINA, Bojana, KREŠEVIČ VRAZ, Silva, VIVOD, Vera, JAUŠOVEC, Darja.

Molecular encapsulation of textiles. V: 3rd International Conference "Smart materials, structures

and systems" [also] CIMTEC 2008, Acireale, Sicily, Italy, June 8-13, 2008. Book of abstracts.

Faenza: CIMTEC Secretariat, 2008, str. 103. http://www.cimtec-

congress.org/2008/book_of_abstracts.pdf. [COBISS.SI-ID 12834326]

MONOGRAFIJE IN DRUGA ZAKLJUČENA DELA

2.11 Diplomsko delo

14. VIVOD, Vera. Nanoenkapsuliranje tekstilnega substrata s pomočjo ß-ciklodekstrina :

diplomska naloga univerzitetnega študijskega programa, (Fakulteta za strojništvo, Tekstil,

Diplomska dela univerzitetnega študija). Maribor: [V. Vivod], 2003. XII, 73 f., ilustr., graf.

prikazi. [COBISS.SI-ID 8272150]

IZVEDENA DELA (DOGODKI)

3.12 Razstava

15. CELCAR, Damjana, KRAJNC, Nina, HODOŠČEK, Ksenija, VIVOD, Vera, JELEN,

Bernarda. Re-jeans >>re-design<< : razstava študentov Oddelka za tekstilstvo Fakultete za

strojništo v Mariboru na temo Oblikovanje oblačil, v avli Fakultete, oktober 2001, Maribor.

Maribor, 2001. [COBISS.SI-ID 8509206]

3.15 Prispevek na konferenci brez natisa

16. MAJCEN, Nataša, VONČINA, Bojana, MAJCEN LE MARECHAL, Alenka, BRODNJAK-

VONČINA, Darinka, BEZEK, Dominika, VIVOD, Vera. Določanje prostega formaldehida na

tekstilnih substratih s pomočjo HPLC : predavanje na posvetu "Pomen znanja in vloga države v

izboljševanju mednarodne konkurenčne sposobnosti tekstilnih in usnjarskih podjetij", Ljubljana,

21. maj 2002. Ljubljana, 2002. [COBISS.SI-ID 7682326]


http://www.cimtec-congress.org/2008/book_of_abstracts.pdf

http://www.cimtec-congress.org/2008/book_of_abstracts.pdf






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9 CURRICULUM VITAE

OSEBNI PODATKI

Ime in priimek: Vera Vivod

Datum in kraj rojstva: 25.12.1977, Maribor

Narodnost: slovenska

Drţavljanstvo: slovensko

Stalno prebivališče: Koritno 38, 2317 Oplotnica

PODATKI O IZOBRAŽEVANJU

1984-1992 Osnovna šola Pohorskega bataljona, Oplotnica

1992-1996 Srednja tekstilna šola, Maribor

1996-2003 Študij na Fakulteti za strojništvo Univerze v Mariboru, smer: Oblačilno

inţenirstvo

2004- Podiplomski študij na Fakulteti za strojništvo Univerze v Mariboru,

Tehniško varstvo okolja

PODATKI O ZAPOSLITVI

2006-2007 Raziskovalka v okviru javnih del na Univerzi v Mariboru, Fakulteta za

strojništvo, Oddelek za inţenirske materiale in oblikovanje

2007-2008 Raziskovalka na Univerzi v Mariboru, Fakulteta za strojništvo, Oddelek za

inţenirske materiale in oblikovanje

crosslinking of cellulose textile substrates using ... · magistrsko delo crosslinking of cellulose...

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