GRAFT-COPOLYMERIZATION OF
STARCH WITH VINYL MONOMERS
by
OM PAL SINGH
Department of Chemistry
Submitted
in fulfilment of the requirements of the degree of
DOCTOR OF PHILOSOPHY
INDIAN INSTITUTE OF TECHNOLOGY/ DELHI
April, 1985
DEDICATION
Dedicated to all the people so devoted
to a particular sequence of informations
and knowledge."
CERTIFICATE
This is to certify that the thesis entitled
GRAFT-COPOLYMERIZATION OF STARCH WITH VINYL MONOMERS"
being submitted by Mr. Om Pal Singh, to Indian Institute
pif Technology for the award of the degree of Doctor of
thilosophy in the Department of Chemistry, is a record
g;r:f
bonafide research work carried out by him. He has
fulfilled the requirements for the submission of the
thesis. The results contained in this thesis have not
been submitted, in part or in full, to any other
;itliversity or Institute for the award of any degree or
diploma.
I I.K. VARMA )
Supervisor
Professor & Head,
Centre for Materials
Science & Technology,
I.I.T. Delhi;
New Delhi - 110016
(INDIA)
/1", pc.
( N.K. SAND
Supervisor
Associate Professor
Department of Chemistry
Indian Institute of Technology,
Delhi; New Delhi - 110016
(INDIA)
ACKNOWLEDGEMENTS
I wish to extend my gratitude to all those aided
in the completion of this dissertation.
I offer my sincerest thanks to Dr. N.K. Sandie,
Associate Professor, Department of Chemistry and
Prof.(Mrs.) I.K. Varma, Head, Centre for Materials Science
and Technology for their guidance and cooperation rather
for a longer period. The former is particularly thanked for
his understanding and cooperation at the critical stage, which
could make it possible to complete this work.
I wish to express my special thanks to all the
teaching and technical staff of Chemistry Department,
Centre for Materials Science & Technology and Textile
Technology Department for their invaluable assistance;
they rendered to me during the duration of this work.
I also wish to acknowledge my special thanks to
my colleagues and friends, especially my seniors
Drs. B.S. Rao, K.R. Murthy, M.S. Choudhary and R.G. Rr-;(1 who
generally extended their help and cooperation whenever it
was needed and virtually had similar time of high and
low spirit.
The authorities of Indian Institute of Technology,
Delhi and Council of Scientific and Industrial Research,
India are acknowledged for the award of research fellowships for carrying out this work.
Finally, but not the least, Mr. Rajesh Arora and
Mr. K. Giri are thanked for neat and accurate typing of
the thesis and so are thanked Mr. K.G. Padam and
Mr. K.C. Saxena for the accurate tracing of the figures.
14e
-i )
( OM PAL SIN
H
CONTENTS
Page
No
LIST OF FIGURES
CHAPTER I.
GENERAL INTRODUCTION AND LITERATURE
REVIEW
1.1
Introduction
1
1.2
Structure of starch
3
1.2.1
Chemical Structure of starch
3
1.2.2
Morphology of starch
7
1.3
Graft-copolymerization of starch
9
1.3.1
Free radical graft-copolymerization
9
(a) Chemical methods
10
(b) Irradiation methods
13
1.3.2
Anionic graft-copolymerization
14
1.3.3
Evidenceof grafting
15
1.4
Properties of graft-copolymers of
starch
17
1.5
Potential applicationAof graftcopolymers of starch
21
1.6
Scope of the present investigations
37
CHAPTER II.
GRAFT-COPOLYMERIZATION OF STARCH WITH
VINYL MONOMERS
2.1
Introduction
39
2.2
Experimental
40
2.2.1
Reagents and their purification
40
2.2.2.1
Grafting of vinyl monomers onto starch
41
ii
2.2.2.2
Separation of homopolymers from graftcopolymers
42
2.2.2.3
Nitrogen estimation
43
2.2.2.4 Homopolymerization of acrylamide
44
2.2.2.5 Kinetics of acrylamide polymerization
45
2.3
Results and Discussions
45
2.3.1
Grafting of vinyl monomers onto starch
45
2.3.1.1 Grafting of acrylamide onto starch
45
2.3.1.2
Grafting of alkyl acrylates onto starch
47
2.3.1.3
Grafting of HEMA, EDMA and AN onto
starch
49
2.3.1.4
Effect of nature of monomer on grafting
51
2.3.2
Effect of variation of reaction parameters on grafting of acrylamide onto
starch
54
2.3.2.1 Homopolymerization of acrylamide
54
2.3.2.2 Graft-copolymerization of acrylamide
onto starch
55
2.3.2.3 Kinetics of acrylamide polymerization
in presence of starch
64
CHAPTER III.
CHARACTERIZATION OF GRAFT-COPOLYMERS
OF STARCH
3.1
Introduction
67
3.1.1
IR spectroscopy.-
67
3.1.2
Molecular weight determination
68
3.1.3
Density measurements
69
3.2
Experimental
71
3.2.1
IR spectroscopy
71
3.2.2 (a) Degradation of starch portion of the
copolymers.
71
iii
3.2.2(b) Determination of viscosity72
3.2.3Density measurements74
3.3Results and Discussions.75
3.3.1Infrared spectra of starch-graft-75
copolymers
3.3.2Viscosity studies of graft-copolymers80
3.3.2.1 Intrinsic viscosity of PAM samples80
3.3.2.2 Viscosity studies of grafted alkyl82
acrylate moieties
3.3.3Effect of grafting of vinyl monomers87
on density of starch
CHAPTER IV,THERMAL BEHAVIOR OF GRAFT-COPOLYMERS
4.1Introduction
89
4.2Experimental
91
4.3Results and Discussions95
4.3.1Effect of the nature of monomer on the95
thermal behavior of starch-graftcopolymers
4.3.2Thermal behavior of starch-graft-102
copolymer with polyacrylamide
4.3.3Thermal behavior of starch-graft-107
copolymers with alkyl acrylates
4.3.4Thermal behavior of starch-graft-113
copolymers of starch with AN,HEMA
and EDMA
CHAPTER V.MECHANICAL PROPERTIES,MORPHOLOGY AND
ENZYMATIC DEGRADATION OF STARCHGRAFT-COPOLYMERS
5.1Introduction
122
iv
5.2Experimental
124
5.2.1Mechanical properties124
5.2.2Morphology of starch-g-polyacrylamide127
copolymers.
5.2.3Enzymatic degradation of starch-g-127
polyacrylamide copolymers.
5.3Results and Discussions.127
5.3.1Mechanical properties of starch-g-127
polyacrylamide copolymers
5.3.2Mechanical properties of starch-g-130
polymethyl acrylate copolymers
5.3.3Mechanical properties of starch-g-132
polyethyl acrylate copolymers.
5.3.4Mechanical properties of starch-g-135
poly('►'L-butyl acrylate) copolymers
5.3.5Effect of polyacrylamide grafting on137
morphology of starch
5.3.6Action of oC -amylase against starch-138
g-polyacrylamide copolymers
CHAPTER VI.GENERAL DISCUSSIONS AND SUMMARY141
6.1General discussions and summary141
6.2Suggestions for the future work153
BIBLIOGRAPHY
LIST OF RESEARCH PAPERS
155