universiti putra malaysia preparation and characterisation...
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UNIVERSITI PUTRA MALAYSIA
PREPARATION AND CHARACTERISATION OF POLYSTYRENE GRAFTED SAGO STARCH
PUSHPAMALAR A/P JANARTHANAN
FSAS 1999 36
PREPARATION AND CHARACTERISATION OF POLYSTYRENE GRAFTED SAGO STARCH
By
PUSHPAMALAR AlP JANARTHANAN
Thesis Submitted in Fulfilment of the Requirement for the Degree of Master of Science in the Faculty of Science and Environment Studies,
Universiti Putra Malaysia
May 1 999
Z' &1)1 eA71 O?t
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� � � H«f � ad fflMIe H«f U6e eH�,
rid � H«f Id<wed �, �, �, 4i4teIt ad. �
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ACKNOWLEDGEMENTS
I wish to take this opportunity to express my heartfelt appreciation
and gratitude to the chairman of my supervisory committee, Associate
Professor Dr. Wan Md. Zin Wan Yunus, and committee members, Dr.
Mansor Hj. Ahmad and Dr. Mohamad Zaki Abdul Rahman for their
invaluable guidance, comments, encouragement and constant support
during the period of this study and for their constructive criticism of this
manuscript during its preparation.
Special thanks also go to the technical staff of the department
special ly Mr. Kamal , Mr. Wahab, Mr. Jegan, Mr. Borhan and Mr. Nazri for
supplying the chemicals and g lass wares on the time needed. I would like to
thank Mr. Ho and Miss Azilah from the Faculty of Veterinary for helping
their technical assistant with the SEM analYSis.
I am a lso grateful to the staff, graduate students and honours
students of the Department of Chemistry especially Md. Lutfor Rahman,
Abu-lIlaiwi Faraj, I sam, Aiza, Laili, Hussein, Chong, Majid and Sec Kin for
their help in one way or another.
I am also greatly indebted to UPM for providing the analysis facilities
and the Government for backing PASCA for me to complete the study
successful ly.
iii
TABLE OF CONTENTS
Page
ACKNOWLEDGEMENTS. . . . . . . . . . ... . .. . . .. . . . ... . . . .. . . . .. . . . . . .. . .. . . . . .. .. . . i i i
LIST O F TABLES............ . ...... ......... ..... ........ . ...... ......... .......... . VII
LIST OF FIGURES .. . . . . .. . . .. . . ... . . . . . . . . . . . . . .. . . . .. . . . .. . . . . ... . . . . . .. . . . .. . . .. ix
LIST OF PLATES. . . . . . ... . . .... . . . .. . . . ...... . . . . . . .. . ... . . . . . . .. . . . .. . . . . . . . . . . . . . . xi
ABSTRACT. . . . . . . . . . . . . . . . . . . . . .. . . . ... . . . . .. . .. . . . . .. . . . . . . . .. . ... . . . . .. . . . . . . . . . . . . .. xii
ABSTRAK . . . .. . ... . . . .. .. .... . .. . . . . . ... . . .. . . . . . . . . . . . . . . . . . . ... . . ....... ... . .. . . . . . .. . xiv
CHAPTER
II
INTRODUCTION.. . .. . . .. . .. . . . .. . . . . . . . . . .. . . . ..... ..... . . .... 1 Starch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Sago Starch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Polymer. . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Graft Copolymerisation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Acidic and Enzymatic Degradation of Starch . . . . 6 Swel l ing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Objectives of the Study. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
LITERATU RE REViEW . .. .... . . . . .. ... . . . .. .... . .. ... . . . ... . 9 Grafting Copolymerisation of Synthetic Monomers onto Natura l Polymers. . . . . . . . . . . . . . . . . . . . . . 9
Grafting Vinyl Monomers onto Wool Fibres. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Grafting Vinyl Monomers onto S i lk Fibres. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Grafting Vinyl Monomers onto Chitosan... . .. ...... . . . . . . . . .. . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . 14 Graft ing Vinyl Monomers onto Gelatin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 5 Grafting Vinyl Monomers onto Chit in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 7 Grafting Vinyl Monomers onto Cotton Cel lu lose. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Grafting Vinyl Monomers onto Modified Cotton. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Grafting Vinyl Monomers onto Starch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
iv
PERPUSTAKAAN III MATERIALS AND METHODS . . . . . . . . . . . ���TI 'UT� MALAYSIA
Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .................. .. ........... 36 Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Grafting . . . .. . .. . ..... .. . . . . . . . . . . . . . . .. . . . . .. . . . . . . .. . . . . 37 Extraction of Homopolymer. . . . . . . . . . . . . . . . . . . . . 38 Calculation of Percentage of Grafting and Percentage of Grafting Efficiency. . . . . . . 38 Determination of Molecular Weight of the Grafted Side Chains. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Gelatinised Sago Starch and I ts Copolymers Degradation . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Swel ling Behavior of Sago Starch-g-Poly(styrene) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . 41 Characterisation of Polystyrene Grafted Sago Starch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
IV RESULTS AND DiSCUSSiON... .. . . . . . . . . . . ... ... ...... 45 Fourier Transform I nfrared Analysis . . . . .. . .. . . . . . . . . . . 45 Thermogravimetry Analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 Differential Scanning Calorimetry Analysis. . . . . . . . 47 Effects of Reaction Temperature. . . . . . . . . . . . . ... . . . . . . . 48 Effects of Concentration of Nitric Acid . . . . . . . . . . . . . . 49 Effects of Styrene Amount . . . . . . . . . . . . . . . . . .. . . . . . . . . . .. . . . . 50 Effects of Ceric Ammonium Nitrate (CAN) Amount .. . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Effects of Reaction Period . . . �................................ 51 Extraction of Homopolymer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 Mechanism of Grafting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Effect of the Presence and Absence of N2 Gas on Styrene Grafting Sago Starch. . . . . . . . . . . . . . . . . . . . . . . . . 53 Swel ling Behavior of Sago Starch-g-Poly(styrene) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Bio-degradability Study by Alpha Amylase. . . . . . . . . . 59 Molecular Weight Determination . . .. . . . .. . . . . . . . . . . . . . . . .. 61 Scanning Electron Microscope .. . . . . . . . . . . . . . . . . . . . . . . . . . . 62
V CONCLUSiONS...... . . .... .. ............ . . .. .. . .. .. .. . .. . . . . . . . . . 93
BIBLIOGRAPHy. . . .. . . ....... . . . . . .. . . . .. . ..... ...... .. . ... ..... .. . . .. ... ... . 96
APPENDIX
A Results of Preparation of Sago Starch-g-Poly( styrene) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 04
v
B
c
Temperature of Decomposition and Differential Weight Losses from TGA. .................. . Results for Swel ling Behavior in Various Solvents, Biodegradabi l ity Studies and Viscosity Measurements of Sago Starch -g-Poly(styrene) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 07
1 08
ViTA................................................................................... 114
vi
LIST OF TABLES
Table
1 Removal of Polystyrene from 8.65 g of Unextracted Sago Starch-g-Poly(styrene) at 25°C in Choloroform
Page
by Shaking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . 52 2 Percentage of Grafting and %GE of Sago Starch-g
Poly( styrene) Prepared in the Presence and Absence of N2Gas. . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
3 Parameters of Swel ling of 54% Polystyrene Grafted Sago Starch (%G). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . 59
A.1 Effects of Reaction Temperature on Styrene Grafting onto Sago Starch. . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
A.2 Effects of Nitric Acid Concentration on Styrene Grafting onto Sago Starch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . 103
A.3 Effects of Styrene Amount on Styrene Grafting onto Sago Starch. . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .. . 104
A.4 Effects of CAN Amount on Styrene Grafting onto Sago Starch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . 104
A.5 Effects of Reaction Period on Styrene Grafting onto Sago Starch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . 105
B.1 Temperature of Decomposition and Different Weight Losses of Sago Starch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
B.2 Temperature of Decomposition and Different Weight Losses of Polystyrene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
B.3 Temperature of Decomposition and Different Weight Losses of 53.92% Sago Starch-g-Poly(styrene) (%G) . . . . . . . . . . . 106
C .1 Percentage of Swelling and Swelling Period in Various Solvents for 53.92% of Polystyrene Grafted onto Sago Starch (%G) at 25°C . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
C.2 Percentages of Swelling and Square Root of Swelling Period in Various Solvents for 53.92% of Polystyrene Grafted onto Sago Starch at 25°C . . . . . . . .. .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . 108
C.3 Percentage of Swel ling and Square Root of Swelling Period in Various Solvents for 53.92% of Polystyrene Grafted onto Sago Starch (%G) the Initial Stages of Swel ling at 25°C . . .. . . 109
C.4 In F and In t of Swelling in Various Solvents for 53.92% of Polystyrene Grafted onto Sago Starch (%G) at the Initial Stages of Swel ling at 25°C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... . . 109
C .5 Absorbance and Amount of Glucose Produced from the Substrate for a Calibration Curve. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . 110
vii
C.6 Amount of Glucose Produced by Using D ifferent Concentrations of Alpha Amylase to Biodegrade the 53. 92% of Polystyrene Grafted Starch (%G) for Various Incubation Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 0
C .7 Amount of G lucose Produced by D ifferent Concentrations of Alpha Amylase to Biodegrade the 53.92% of Polystyrene Grafted Sago Starch (%G) and Gelatin ised Sago Starch for Various I ncubation Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 1
C .8 Reduced Viscosity and Concentration of Solution for 1 1 . 1 0% Grafted Polystyrene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 1
C.g Reduced Viscosity and Concentration of Solut ion for 2 1 . 65% Grafted Polystyrene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 2
C . 1 0 Reduced Viscosity and Concentration of Solut ion for 33.24% Grafted Polystyrene. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 2
C . 1 1 Reduced Viscosity and Concentration of Solution for 42.89% Grafted Polystyrene. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 3
C . 1 2 Reduced Viscosity and Concentration of Solut ion for 53. 92% Grafted Polystyrene. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 3
C . 1 3 Viscosity-Average Molecular Weight and Various Percentage of Grafted Polystyrene . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 3
viii
LIST OF FIGURES
Figure Page
1 Chemical Structure of Starch . . .. . ... . .... . .. . . . . . . . . . . . . . . . .. ... . .. .... . . . . 3 2 FTIR Spectrum of Sago Starch . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 64 3 FTIR Spectrum of Polystyrene . .... . . ..... .. . . . ..... . .. . . . .. .... . . . . .. ..... . 65 4 FTIR S pectrum of Grafted Polystyrene Chain . . . . . . . ... .. . . . . . . . . . . . 66 5 TGA Thermogram of Sago Starch .... . .. . . . . . . . . . . . . . . . . . . ........ . .. . . . . . . 67 6 TGA Thermogram of Polystyrene . . .. . . . . . . . . . .. . .. . . . . . . . . . . . . . . . . .. . . . . . . . 67 7 TGA Thermogram of 54% Sago Starch-g-Poly(styrene)
(%G) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 8 DSC Curve of Sago Starch. . . . . . . .. . .. . .... ..... . . . . .... . . . . .. . . . .. . . . . . . ... 69 9 DSC Curve of Polystyrene . . ... . . . . . . . . . . .. . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . ..... 70 1 0 DSC Curve of 54% Sago Starch-g-Poly(styrene) (%G) . .. . . . . . . 7 1 1 1 Effects of Reaction Temperature on Percentage of Grafting
and Percentage of Grafting Efficiency.. ..... . . . . .. . . . . . . .. . . . . .. . . .. . . . 72 1 2 Effects of Concentration of Nitric Acid on Percentage of
Percentage and Percentage of Grafting Efficiency .... . .... ... . . . 73 1 3 Effects of Amount of Styrene on Percentage of Grafting
and Percentage of Grafting Efficiency. . . . . . . . . . . . . . . . . . . .... . . . . . . . . . . . 74 1 4 Effects of Amount of CAN on Percentage of Grafting
and Percentage of Grafting Efficiency . .. . . .............. . . . . .. . .... . . . .. 75 1 5 Effects of Reaction Period on Percentage of Grafting
and Percentage of Grafting Efficiency. . . .. . . . . . . .... . . . . . .......... . . . . . 76 1 6 Mechanism of Graft Copolymerisation... . . . . ... ...... . . ........ .. .. . 78 1 7 Percentage of Swel ling as a Function of Swel ling Period
for Sago Starch-g-Poly(styrene).......... . . ....... . . .. .... .... . .... . ... 79 1 8 Percentage of Swel ling as a Function of Square Root
of Swel ling Period for Sago Starch-g-Poly(styrene) at the Initial Stages of Swel ling .. ... ......... . ....... ..... . ....... . . ..... . . . . 80
1 9 In F as a Function of Int for Sago Starch-g-Poly( styrene) at the Initial Stages of Swelling at 2SoC.............................. 81
20 A Calibration Curve for Glucose....................................... 82 2 1 Amount of Glucose Produced i n Different Concentrations
of Alpha Amylase for 53.92% Polystyrene Grafted Starch (%G) and Gelatinised Sago Starch.... .... . . . . . ..... ........ .. .. .. . . . ... 83
22 Amount of Glucose Produced by Different Concentrations of Alpha Amylase for Various Incubation Periods.. .. .... . . . . . . . . 84
23 Reduced Viscosity Versus Concentration for 1 1.1 0% Grafted Polystyrene........... ...... .... . . . . . .... ..... . . . .. ..... .... . . ........ .. 85
24 Reduced Viscosity Versus Concentration for 2 1 . 65% Grafted Polystyrene............. . ........... . . . . . .... . ..... . . ..... .... .. .... .. . . 86
ix
25 Reduced Viscosity Versus Concentration for 33.24% Grafted Polystyrene.. . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . ... . .. .. .. . .... . . . . . . 87
26 Reduced Viscosity Versus Concentration for 42.89% Grafted Polystyrene . . . . . . . . . . . .. . . .. . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . .. . . . 88
27 Reduced Viscosity Versus Concentration for 53.92% Grafted Polystyrene.. . . . .. ...... .. . . . .. . . ..... . . . . . . . .. . . . . . . .. . . . . . . . . .. .. . . . . . . 89
28 Average Molecular Weight (Mv) Versus Percentage of Grafted Polystyrene. . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . . . . . . .. . . . . . . . . . . . . . . . . . . . 90
x
LIST OF PLATES
Plate Page
1 SEM Photograph of Granular Sago Starch at 400x. . .. . . . . . . 91 2 SEM Photograph of Gelatin ised Sago Starch
at BOx. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 3 SEM Photograph of 53. 92% Sago Starch-g-Poly(styrene)
(%G) at 25x. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
xi
Abstract of thesis submitted to the Senate of Universiti Putra Malaysia in fulfilment of the requirement for the degree of Master of Science
PREPARATION AND CHARACTERISATION OF POLYSTYRENE GRAFTED SAGO STARCH
By
PUSHPAMALAR AlP JANARTHANAN
May 1 999
Chairman: Associate Professor Wan Md. Zin Wan Yunus, Ph.D.
Faculty: Science and Environmental Studies
Styrene grafting onto sago starch was carried out by using eerie
ammonium nitrate (CAN) as a redox initiator. The parameters affecting the
grafting reaction were i nvestigated and the optimum conditions obtai ned are
as fol lows: temperature, 50°C ; n itric acid concentration, 0 .01 M; amount of
styrene, 0 .35 mol; amount of CAN, 1 6.8 x 1 0-4 mol and reaction period , 2h.
Percentages of grafting and grafting efficiency under the optimum condition
were 53.92% and 73.21 %, respectively. Reactions in the presence of
n itrogen gas resulted in higher percentages of grafting and grafting
efficiency.
FTIR spectra analysis of the grafted chain and polystyrene was
identical indicating that styrene was successful ly grafted onto sago starch.
TGA thermograms, DSC curves and SEM photographs of sago starch-g-
xii
poly( styrene) and the original polymers (sago starch and polystyrene) were
different which suggested that styrene was grafted onto sago starch. The
bio-degradabi l ity study using a-amylase showed that the rate of degradation
of gelatin ised sago starch was h igher than that of sago starch-g
poly(styrene). The highest rate of degradation of sago starch-g
poly(styrene) was obtained at 50 ppm of a-amylase concentration. Viscosity
measurements showed that the intrinsic viscosity and the average molecular
weight (Mv) increased with the increase in the percentage of grafted
polystyrene. The Mv of the various percentages of grafted polystyrene were
in the order of 1 04 . The results obtained from the swel l ing of sago starch-g
poly(styrene) in polar and non polar solvents showed that the percentage of
swel l ing at equ i l ibrium and the swel l ing rate coefficient decreased in the
fol lowing order: DMSO > water > acetone > cyclohexanone � CHCh >
toluene � CCI4. Diffusions of the solvents onto the polymers were found to
be of a F ickian only for DMSO.
xiii
Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai memenuhi keperluan untuk ijazah Master Sains
PENYEDIAAN DAN PENCIRIAN KOPOLIMER KANJI SAGOPOLISTIRENA
Oleh
PUSHPAMALA R AlP JANARTHANAN
Mei 1 999
Pengerusi: Profesor Madya Wan Md. Zin Wan Yunus, Ph.D.
Fakulti: Pengajian Sains dan Alam Sekitar
Kajian bagi pengkopol imeran cangkuk sti rena ke atas kanji sagu
telah dibuat dengan menggunakan serium ammonium nitrat (SAN) sebagai
pemula tindak balas redoks. Parameter-parameter yang memberi kesan ke
atas pengkopo l imeran telah d ikaji dan keadaan optimum tindak balas yang
d iperoJeh i adaJah seperti berikut : suhu tindak balas, 50°C; kepekatan asid
nitrik, 0.01 M; amaun stirena, 0.35 mol; amaun SAN, 16.8 x 10-4 mol dan
masa t indak balas, 2 jam. Peratus-peratus pengkopol imeran cangkuk dan
kecekapan pengkopol imeran cangkuk di bawah keadaan optimum adalah
masing-masing 53.92% dan 73.21%. Tindak balas dengan kehadi ran gas
nitrogen menghasi lkan peratus-peratus pengkopol imeran cangkuk dan
kecekapan pengkopolimeran cangkuk adalah lebih tinggi.
Anal isis spektra daripada spektrofotometer inframerah untuk
pol isti rena yang dicangkuk adalah sarna dengan pol istirena piawai. In i
xiv
menunjukkan bahawa stirena berjaya dicangkukkan ke atas kanji sagu.
Termogram-termogram daripada termogravimetri, keluk-keluk daripada
kalorimetri pengimbasan pembezaan dan gambar-gambar daripada elektron
mikroskop untuk kopol imer kanji sagu-pol ist irena dan pol imer permulaan
(kanj i sagu) adalah berbeza. Ini juga mencadangkan bahawa stirena telah
dicangkukkan ke atas kanji sagu.
Kajian mengenai penguraian secara biologi dengan menggunakan a
ami lase menunjukkan bahawa kadar penguraian untuk kanji sagu yang
telah digelatinkan adalah lebih tinggi daripada kopol imer kanji sagu
pol ist irena. Kadar penguraian yang pal ing tinggi bagi kopol imer kanji sagu
pol istirena diperolehi dengan menggunakan a-ami lase pad a kepekatan 50
ppm. Pengukuran kel ikatan larutan cai r menunjukkan kel ikatan intrinsik dan
purata j is im molekul (Mv) meningkat dengan meningkatnya peratus
pol istirena yang dicangkuk. Purata j is im molekul untuk pelbagai peratus
pol istirena yang d icangkuk adalah dalam urutan 104. Keputusan kajian
pengembungan kopol imer kanji sagu-pol istirena d i dalam plarut-pelarut
berkutub dan tak berkutub menunjukkan bahawa peratus pengembungan
pada keseimbangan dan pemalar kadar pengembungan menurun secara
berikut: DMSO > air> acetone> cyclohexanone ::::: CHCI3 > toulena ::::: CCI4.
Pembauran pelarut ke dalam kopol imer kanji sagu-pol ist irena adalah secara
Fickian hanya bagi DMSO.
xv
CHAPTER I
INTRODUCTION
Starch
Starch is one of the cheapest, bio-degradable and most readily
available of al l renewable natural polymers exists in plants. It is anhydrous
D-glucose consisting of mixture of amylose and amylopectin as shown in
Figure 1. Amylose is a linear polymer of molecu lar weight between one
thousand and one mil lion and made up of several hundred g lucose units
linked by 0: 1 -4 glycosidic linkages. Amylopectin is a branched polymer of
glucose units of 0: 1 -6 g lycosidic linkages at the branching points and 0: 1 -
4 glycosidic linkages in the linear region. The molecular weight of
amylopectin can run into several millions. Starch is not truly thermoplastic
like most synthetic polymers. However, it can be melted and flow at high
temperatures under pressure and shear. If the mechanical shear becomes
too high then starch wil l degrade to form products with low molecular
weight. Addition of water or other plasticisers enables starch to flow u nder
milder conditions and reduces degradation considerably (Wurzburg,
1989). Starch has both the crystal and amorphous structures (Gao et al.,
2
1994}. Because of their crystal l inity, most starch granules show a Maltese
crosses when observed under polarized light. Native starch granules have
a crystallinity range from 15 to 45%. The granule appears to be made up
of alternating semi-crysta l l ine and crysta l l ine shel ls which are between
120 and 420 nm thick. Sol id state 13H NMR analysis shows that the level
of hel ical order in the starch granules is significantly greater than the
extent of crystal l i ne order. Consequently, it appears that much of
amylopectin in semi-crystal l ine shel ls is i n the double hel ica l form,
although it is not crystal l ine (Gal lant et al., 1997).
The properties of starch can be significantly improved by blending it
with synthetic polymers. However, most of the synthetic polymers are
immiscible with starch at the molecular level which leads to the poor
performance of these blends. In order to overcome this drawback, graft
copolymerisation of vinyl monomers on the starch backbone is used to
modify starch (Vaidya et aI., 1995). A review of the l iterature i ndicates that
although the grafting of starch with synthetic monomers has been known
for 30 years, very few processes have led to ful l-scale commercialisation.
Sago Starch
Sago starch has been known to exist for 400 years and produced
from sago palm plants. There are two main species of sago palm:
AMYLOSE-linked lhrouglw - D- (I-t4) glucosidic bonds
----_.-\----
AMYLOPECTIN -+ ('J. - D- (1 --t 4) glucosidic bond
jH - 0 -
-+ I branch linked ('J. - 0 (I -+ 6) glucosidic bond.
IH �O-
Figure 1 : Chemical Structure of Starch
3
4
Metroxylon rumphii with the thorny main stem and Metroxylon sagu
Rottbboll with thornless main stem (Jeffrey, 1 986) . Sago starch studied by
the scanning electron microscope are deformed prolate el l ipsoidal shape
particles which are larger than those of maize and tapioca (Griffin, 1 977) .
In 1 941 , Thomas Schoch showed that sago starch consists of 27%
amylose and 73% amylopectin (Wurzburg, 1 989). Quality characteristics
of sago starch depend on interrelated factors such as raw material , mode
of transport, supply and quality of water, method and efficiency of the
extraction and purification processes (Jeffrey, 1 986) .
Polymer
Polymers are large molecules made up by the repetition of sma l l ,
simple chemical units. The essential requirement for a smal l molecule to
qualify as a monomer is the possession of two or more bonding sites. It is
produced through a process known as polymerisation in which the
monomer molecules react chemical ly to form a linear chain by covalent
bond. The polymerisation techniques are classified as addition and
condensation polymerisations. Linear chain polymers composed of
chemical ly identical monomers cal led homopolymers. The polymers
incorporating two or more chemical ly different types of monomers onto the
chain are cal/ed copolymers.
5
PERPUSTAKAAN The copolymer structure can be divide'lr�X¥ciHcT6��fMr�YSlA
block or graft copolymers. When two different monomers in a copolymer
are distributed at random throughout the chain, the polymer is called a
random copolymer. If the units of two monomers are distributed
alternatively throughout the chain, this polymer is called alternating
copolymer. Polymers containing long stretches of two or more monomers
linked together by chemical valences in one single chain is called block
copolymers. A graft copolymer is a branched block arrangement in which
the polymer structure consisting of one polymer with another polymer
branched to it (Billmeyer, 1 984 ; Hiemenz, 1 984) .
Graft Polymerisation
Graft copolymerisation is a well known method to modify the
chemical and physical properties of polymers. Graft copolymerisation
results from the formation of an active site at a point on a polymer
molecule back bone and exposure to a second monomer. Most of the graft
copolymers are formed by free radical polymerisation using chemical or
radiation methods. The radiation method is carried out by irradiating the
polymer using gamma or ultraviolet radiations. The chemical method is
through the formation of free radicals, cations and anions by a suitable
chemical reaction. Starch graft copolymers are becoming important
because of their potential application in industry. The wide range of
available vinyl and other monomers suggests that grafting is a powerful
6
method for producing modification in starch properties and enlarging the
range of utilization (Athawale and Rathi, 1997a).
Acidic and Enzymatic Degradation of Starch
Starch is a bio-degradable natural polymer. It degrades when the
enzyme or acid molecule attacks the starch back bone. Enzymatic and
acidic attacks of starch are similar since they both involve hydrolysis of
the bonds in the starch. In both processes the semi-crystallinity of the
granules are more easily and rapidly hydrolysed than the crystalline
layers. The size of the acid molecule is smaller than the enzyme which
allows the acidic the attack to occur on a finer scale than the enzymatic
attack. The acid degradation is affected by the acid concentration,
temperature and the presence of alcohols. Prolonged exposure to acid
molecules will allow the acid molecules to penetrate through even the
crystalline regions of the granule and act on the a-1, 6 bonds of the
amylopectin molecules in the starch (Cui and Oates, 1997).
During the enzymatic attack the less crystalline part of the starch
granules is easily digested than the hard crystalline part. Pits are formed
randomly all over the granule surface and combined to form canals which
will enlarge and merge (Gallant et at. , 1997). Alpha amylase from a new
source (Aspergillus fumigatus) has been shown to have a different pattern
7
of degradation . It forms pores at the surface of the g ranules even with the
resistant starches (Gallant et al ., 1 997) .
Swelling
Stud ies on the d iffus ion of po lar and non polar so lvents in swel lab le
po lymeric systems have received considerable attention because of the
important applications of b iomedical, pharmaceutical , enviro nmenta l and
ag ricu lture engineering . In a swel l ing process it is necessary to take into
account the force of friction . When the polymer is swel l ing in a so lution
from the d ry state , i t takes time for a network to swel l from the surface to
the core. The swel l ing processes consist of the interactio n with the so lvent
and the polymer, fo l lowed by the so lvent penetration inside the network
which induces a po lymer swel l ing (Budtova, 1 997) . The percentage of
swel l ing (%S) can be calculated from the fo l lowing relation:
%S = [ ( mt - ma )/ ma] x 1 00 ...... . . . . . . . . .. . . . . ( 1 )
where mt is the mass of swol len polymer at time t , and ma is the in it ial
mass of the swo l len polymer.
8
Objectives of the Study
The objectives of this study are as follows:
1. To prepare the grafting of styrene onto sago starch by using ceric
ammonium nitrate as the initiator and to study the effecting reaction
parameters to obtain an optimum condition which leads to maximum
grafting.
2. To characterise sago starch-g-poly(styrene) by Fourier Transform
Infrared Spectroscopy, Thermogravimetry, Differential Scanning
Calorimetry and Scanning Electron Microscopy.
3 . To investigate the bio-degradability of the polystyrene grafted sago
starch and gelatinised sago starch by using a-amylase as the enzyme.
4. To study the swelling behavior of polystyrene grafted sago starch in
various types of solvent to determine the swelling at equilibrium and the
nature of diffusion of the solvents on the grafted copolymer.
5. To carry out viscosity measurements for various percentages of
grafted polystyrene to determine the average molecular weight.
CHAPTER I I
LITERATURE REVIEW
Grafting Copolymerisation of Synthetic Monomers onto Natural Polymers
The modification of natural polymers is a promiSing method for the
preparation of new materials. This enables one to introduce special
properties and enlarge the field of the potential appl ications of those
biopolymers of abundance. Among the diverse modifications that are
possible to achieve, grafting of synthetic polymers is a convenient method
(Yazdani-Pedram and Retuert, 1 997) .
Grafting Vinyl Monomers onto Wool Fibres
Chemical modification of wool through graft copolymerisation of
vinyl monomers can be effective in improving some of the fibre properties.
Grafting of vinyl monomers was achieved by free radical initiation
mechanism. Free radical can be produced by both chemical and -physical
methods, including the use of redox systems, oxid izing agents, low and
h igh energy radiation. The monomer may interact with free radical sites
9