L B / D O N ^ \sjO 
PREPARATION AND CHARACTERIZATION OF LOW DENSITY 
POLYETHYLENE-BASED COMPOSITE MATERIALS CONTAINING 
RICE-STRAW AS A FILLER 
by * - * 
6 6 
c o n A 4 6 . 0 * 2 . 3 2 ^ ' 0 l 8 ' 6 ? 
S. S. Dodampegamage to 
This Thesis was submitted to Department of Chemical and Process Engineering of 
the University of Moratuwa in partial fulfillment of the requirement for the Degree ^01 
of Master of Science in Polymer Technology / v 
Department of Chemical and Process Engineering - i, 
University of Moratuwa 
Sri Lanka, Ar 8 
University of Moratuwa 
2004 niMniiiiiiiliiiiiimnrniii 
8 2 5 4 3 
82548 
D E C L A R A T I O N 
I hereby declare that this submission is a result of a work carried out by me and to 
the best of my knowledge, it contain no material previously written or published by 
another person nor material which has been accepted for the award of any degree or 
acceptable qualification of a university, or other Institute of higher learning, except 
where the due reference to the material is made. 
(S. S. Dodampegamage) 
December 21 2004 
To the best of my knowledge, the above particulars are correct. 
(Dr. B A J K Premachandra) 
0 
A B S T R A C T 
This thesis consists of four chapters. Chapter one contains an introductory part 
including scope and the objectives of the research. Since the present research is 
divided in to three major parts, chapter two, three and four are arranged 
accordingly. Each chapter includes an introduction discussing the relevant 
^ literature, the experimental work, results and discussions and finally, the 
conclusions drawn. The contents of this thesis can be best summarized as follows. 
P r e p a r a t i o n a n d charac te r iza t ion of composi te mater ia l s con ta in ing L D P E and 
u n t r e a t e d r ice-s t raw powder 
A series of Low Density Polyethylene (LDPE)/straw composites containing 
different amount of straw (as wt %) were prepared using rice-straw powder having 
• three different particle sizes (50 um, 90 urn and 250 |xm). Mixing was done by melt-
mixing technique, where LDPE and straw powder were mixed in a Brabender 
• plasti-corder, which was operating at 170°C temperature and 60 rpm. The 
composites were studied by using Fourier Transform Infra-red spectroscopy (FTIR). 
The failure modes, tensile properties, water absorption, biodegradation and 
weatherability were investigated as a function of the weight percentage as well as 
particle size of straw filler in the composite. It was found that the incorporation of 
straw into LDPE matrix has reduced the ductility of the composite. The mechanical 
properties of the composites, especially the tensile strength and elongation at break 
were significantly low compared to those of neat LDPE. A significant improvement 
in modulus was shown by the composites. It was found that the tensile properties 
were depended on the amount and particle size of the straw in a composite. 
Biodegradability of cellulose component in the rice-straw and LDPE-straw 
composites, after exposure to cellulase enzyme solution, was assessed by weight 
loss measurements. It was found that rice-straw sample is readily biodegradable but 
degradability of the composite samples was not significantly affected by the 
cellulase enzyme. 
n 
The extent of degradation after the weathering process was assessed by the loss of 
tensile strength measurements of the composites after incubation of the samples in a 
weather meter, which was at 70° C and continuous UV and moisture cycles for five 
days. It was found that the degradability of the composite samples depends on the 
amount of the rice-straw in a sample. 
P r e p a r a t i o n a n d charac te r i za t ion of maleic a n h y d r i d e grafted L D P E and 
composi te ma te r i a l s wi th maleic a n h y d r i d e graf ted L D P E and un t r ea t ed rice 
s t r aw 
A series of maleic anhydride grafted LDPE samples with different w t% ' s of maleic 
anhydride and dicumyl peroxide were prepared and studied. The maleic grafted 
LDPE samples were prepared by melt free radical grafting method, where the 
grafting reaction of LDPE was carried out with the free radical initiator (Dicumyl 
peroxide) in a Bra-bender PL2000 plasti-corder operating at 170 0 C. Fourier 
transform infrared (FTIR) spectroscopy confirmed the grafting of maleic anhydride 
on LDPE backbone. Melt viscosity measurements and tensile measurements of 
grafted LDPE samples confirmed the unwanted cross- link formation during the 
grafting reaction. 
A series of composites with maleic grafted LDPE and different composition of 
untreated rice-straw were prepared using simultaneous grafting and mixing 
technique. In this regard LDPE, maleic anhydride, dicumyl peroxide and rice-straw 
were fed in to the hot plasti-corder operating at 170° C, where melt free radical 
grafting reaction as well as melt mixing of straw filler with LDPE were occurred. 
Fourier transform infrared (FTIR) spectroscopy confirmed the formation of new 
interface interaction (ester bond) between the rice-straw and maleic grafted LDPE. 
The failure modes , mechanical properties, rheological properties, water absorption, 
biodegradation and weatherability were investigated with respect to the weight 
percentage of the straw as well as particle size of the straw in the composite sample. 
Improved mechanical properties, especially tensile strength and modulus were also 
evidenced the compatibility and interface interaction in the maleated LDPE-straw 
composites. It was found that the tensile and modulus values of maleated LDPE-
straw composites having smaller particle size and higher filling level of rice-straw 
in 
to be higher due to the formation of more interactions at the interface. According to 
the melt viscosity and shear rate analysis, higher melt viscosity was shown by the 
maleated LDPE-straw composites due to the undesirable cross-links formed in the 
maleation process. Compared to the LDPE-straw composites, the corresponding 
maleated LDPE-straw composites have shown higher water absorption. As in the 
case of LDPE-straw composite these composites also have not shown any weight 
loss after the digestion with cellulase enzyme but have shown a considerable 
degradability after the weathering process. 
P r e p a r a t i o n a n d charac te r iza t ion of composi te mate r ia l s wi th malea ted L D P E 
and t r e a t e d r ice-s t raw 
Using simultaneous grafting and mixing technique, another series of composites 
were prepared with maleated LDPE and treated rice-straw powder. In order to 
remove lignin and other waxy substances, rice-straw was subjected to steam 
explosion and hot alkyl treatments. By the chemical analysis results it was found 
"that most of the lignin.and other waxy substances have removed from the straw 
surface. Fourier transform infrared (FTIR) spectroscopic results also confirmed the 
removal of lignin and thereby increase of wt% of cellulose in rice-straw. Further 
FTIR analysis of the composite sample more clearly showed the formation of 
interface ester linkages between the treated straw and maleated LDPE. 
Similar to the chapter three, different property analysis such as mechanical, water 
absorption, enzymatic digestion and weatherability were carried out with respect to 
the weight percentage and particle size of the straw filler. Compared to the LDPE-
straw composites and maleated LDPE-untreated straw composites, significant 
improvement in the mechanical properties were resulted in the maleated LDPE-
treated straw composites. It was also evidenced that the removal of lignin by the 
treatment processes has enhanced the interface interaction of maleated LDPE-straw 
system. Further it was found that filler properties such as the amount of straw filler 
in the composite and the particle size of straw also govern the mechanical properties 
of the composites. Providing more surface area and more OH groups to form ester 
bonds, composites having smaller size and higher amount of straw have shown 
higher tensile and modulus values. Also in this series the percentage elongation 
properties were significantly reduced with the introduction of the treated straw in to 
iv 
LDPE but the reduction is significantly lower than the composites with maleated 
LDPE-untreated straw. The extent of the biodegradability of the composites with 
cellulase enzyme was also analyzed by the weight loss measurements. As in the 
above two composite series maleated-treated composites also have not shown 
significant digestion with the cellulase enzyme. 
r 
v 
A C K N O W L E D G E M E N T S 
I wish to express my deepest gratitude to my supervisor, to whom I am deeply 
indebted, Dr Jagath K Premachandra, Department of Chemical and Process 
Engineering, University of Moratuwa. His attentiveness and interest in this study, 
advice and criticism have motivated me immensely and guided me on the pathway 
to the successful completion of this work. 
I would like to express my deep gratitude to Dr. Shantha Walpalage, Head of the 
Polymer Division, Department of Chemical and Process Engineering, University of 
Moratuwa for his kind co operation given to me on completion of this work. Further 
I would like to acknowledge Dr. (Mrs.) Chandima K. Jayasuriya, Department of 
Chemistry, University of Kelaniya and Mr. S. A. S. Perera, Department of Chemical 
and Process Engineering, University of Moratuwa, for their helpful ideas, advices 
given to complete this work successfully. 
I would like to acknowledge Dr. Gamini Senevirathna, Deputy Director Research 
(Technology), Rubber Research Institute, Mrs. Dilhara Edirisinghe, for their kind 
assistance in granting me to carryout practical in their institute premises. I render 
my heartiest gratitude and special thank to Mr. H. N. K. K. Chandralal, Mr. L. G. P. 
Lelwela and Mrs. Manel Mahanama, for their immense co operation and assistance 
towards my research and further, acknowledge all staff members and technical 
officers of Rubber Research Institute, Ratmalana, for their kind co operation. 
My deep gratitude goes to Dr. N. Munasinghe, Head of the Materials Engineering 
Department, University of Moratuwa, for his kind assistance in granting me to use 
laboratory equipments in his department. I further, extend my gratitude and special 
thank to the academic staff member Mr. V. S. C. Weragoda and the senior staff 
technical officer, Mr. Sarath Chandrapala for their immense co operation and 
assistance towards my research work. 
vi 
I further, acknowledge Dr. Sudantha Liyanage, Head of the Polymer Division, 
Department of Chemistry, University of Sri Jayawardenapura for granting me 
permission to use laboratory facilities in the department. I acknowledge with special 
thanks to the Technical officer Mr. Sagara Dias. for his immense assistance given to 
me. 
I further extend my deep gratitude to Dr. (Mrs.) Padma Amarasinghe, Department 
of Chemical and Process Engineering, University of Moratuwa, all academic staff 
and the laboratory staff of the department for their support in numerous ways, for 
which I will always be thankful. I will be indebted to Asian Development Bank for 
granting financial assistance for the course of study. 
Finally, I acknowledge with heartiest gratitude to my husband and my best friends 
Gayani and Manju who supported me in numerous ways, which motivated me to 
complete this work successfully. 
• 
/ v . 
vii 
T A B L E O F C O N T E N T S Page No. 
Declara t ion i 
A b s t r a c t ii 
Acknowledgemen t s iv 
Tab le of contents viii 
Lis t of Tab les xiv 
List of F igures xv 
List of abbrev ia t ions xx 
C H A P T E R O N E - B A C K G R O U N D M O T I V A T I O N 1 
1.1 Background motivation 2 
1.2 Objectives 5 
C H A P T E R T W O - P R E P A R A T I O N AND 
C H A R A C T E R I Z A T I O N O F L D P E - S T R A W C O M P O S I T E S 6 
2.1 I N T R O D U C T I O N 7 
2.1.1 Polymer composites 7 
2.1.2 Lignocellulosic fillers 9 
2.1.3 Chemical composition of lignocellulosic materials 10 
2.1.4 Rice-straw as a filler 12 
2.1.5 Degradation of rice-straw 13 
2.1.6 Enzymatic degradation of cellulose 14 
2.1.7 Advantages and disadvantages of straw as a filler 16 
• 
2 . 2 T H E O R I E S O N T H E E F F E C T O F F I L L E R S O N T H E 
F A I L U R E M O D E S AND M E C H A N I C A L 
P R O P E R T I E S O F A C O M P O S I T E 19 
2.2.1 The effect of fillers on the failure modes of a 
polymeric composite 19 
2.2.2 The effect of fillers on extension 20 
2.2.3 The effect of fillers in tensile strength of a polymeric 
composite 20 
2.2.4 The effect of fillers in modulus of a composite 22 
2.3 E X P E R I M E N T A L 24 
2.3.1 Materials 24 
2.3.2 Preparation of the straw powder 24 
2.3.3 Preparation of composites with LDPE and straw 
powder 24 
2.3.4 FTIR analysis of LDPE and PES composites 25 
2.3.5 Determination of the tensile properties of the PES 
composites 25 
2.3.6 Determination of the water absorptivity and 
biodegradability of PES composites 25 
2.3.7 Determination of the weatherability of PES composites 26 
2.4 R E S U L T S A N D D I S C U S S I O N 27 
2.4.1 Analysis of FTIR spectra of PES composites 27 
2.4.2 Tensile properties of PES composites 30 
2.4.2(a) Failure modes of PES composites 30 
2.4.2(b) Tensile properties of PES composites 38 
2.4.3 Water absorption and biodegradadility of PES 
composites 44 
2.4.4 Determination of the weatherability of PES composites 48 
2.5 C O N C L U S I O N S 55 
ix 
C H A P T E R T H R E E - P R E P A R A T I O N AND 
C H A R A C T E R I Z A T I O N O F M A L E I C A N H Y D R I D E 
G R A F T E D L D P E AND M A L E A T E D L D P E - S T R A W 
C O M P O S I T E S 51 
3.1 I N T R O D U C T I O N 52 
3.2 E X P E R I M E N T A L 58 
3.2.1 P R E P A R A T I O N AND C H A R A C T E R I Z A T I O N O F 
M A L E I C A N H Y D R I D E G R A F T E D L D P E 58 
3.2.1.1 Materials 58 
3.2.1.2 Recrystalization of maleic anhydride 58 
3.2.1.3 Preparation of maleic anhydride grafted LDPE 
(maleated LDPE) 58 
3.2.1.4 Spectroscopic analysis of maleated LDPE 59 
3.2.1.5 Analysis of rheological properties of LDPE and 
maleated LDPE change with maleation 
(Rheological analysis of LDPE and different 
maleated LDPE samples) 59 
3.2.1.6 Determination of the tensile properties of different 
maleated LDPE samples 59 
3.2.2 P R E P A R A T I O N AND C H A R A C T E R I Z A T I O N O F 
C O M P O S I T E M A T E R I A L S W I T H M A L E I C 
A N H Y D R I D E G R A F T E D L D P E AND R I C E 
S T R A W 60 
3.2.2.1 Materials 60 
3.2.2.2 Preparation of composite samples with maleic 
anhydride grafted LDPE and rice-staw 60 
3.2.2.3 Determination of the tensile properties of MPES 
composite samples 61 
3.2.2.4 FTIR analysis of MPES composite samples 61 
3.2.2.5 Analysis of rheological properties of MPES 
composites 
3.2.2.6 Determination of the water absorptivity and 
biodegradability of MPES composites 
3.2.2.7 Determination of weatherability of MPES 
composites 
3.3 R E S U L T S AND D I S C U S S I O N 
3.3.1 P R E P A R A T I O N AND C H A R A C T E R I Z A T I O N 
O F M A L E I C A N H Y D R I D E G R A F T E D L D P E 
3.3.1.1 Spectroscopic analysis of maleic anhydride grafted 
LDPE samples 
3.3.1.2 Rheological analysis of LDPE and different 
maleated LDPE samples 
3.3.1.3 Determination of the mechanical properties of the 
maleated LDPE samples 
3.3.2 P R E P A R A T I O N AND C H A R A C T E R I Z A T I O N 
O F C O M P O S I T E M A T E R I A L S W I T H 
M A L E I C A N H Y D R I D E G R A F T E D L D P E AND 
R I C E S T R A W 
3.3.2.1 FTIR analysis of MPES composite and LDPE 
sample 
3.3.2.2 Failure modes of MPES composites 
3.3.2.3 Determination of Tensile properties of MPES 
composites 
3.3.2.4 Analysis of rheological properties of MPES 
composites 
3.3.2.5 Determination of the water absorptivity and 
biodegradability of MPES composites 
3.3.2.6 Determination of weatherability of MPETS 
composite samples 
3.4 C O N C L U S I O N S 
• 
C H A P T E R F O U R - P R E P A R A T I O N AND 
C H A R A C T E R I Z A T I O N O F C O M P O S I T E M A T E R I A L S 
W I T H M A L E I C A N H Y D R I D E G R A F T E D L D P E AND 
T R E A T E D R I C E S T R A W 88 
4.1 I N T R O D U C T I O N 89 
4.2 E X P E R I M E N T A L 92 
4.2.1 Materials 92 
4.2.2 Modification of rice-straw by mercerization and 
steam explosion methods 92 
4.2.3 FTIR spectral analysis of treated straw powder 
and untreated straw powder. 93 
4.2.4 Chemical analysis of components of straw 
powder samples before and after treatments 93 
4.2.5 Preparation of maleic anhydride grafted LDPE-
treated rice-straw composites 93 
4.2.6 FTIR spectral analysis of MPETS composites and 
MPES composites 94 
4.2.7 Determination of tensile properties of the MPEST 
composites 94 
4.2.8 Determination of the water absorptivity and 
biodegradability of MPETS Composites 94 
4.2.9 Determination of weatherability of MPETS 
composites 94 
Xll 
4.3 R E S U L T S AND D I S C U S S I O N 
4.3.1 FTIR spectral analysis of untreated straw powder 95 
and treated straw powder 
4.3.2 Chemical analysis of the components of straw 95 
powder samples before and after the treatments 
4.3.3 FTIR spectral analysis of MPETS composites and 96 
MPES composite samples 
4.3.4 Analysis of failure modes of MPETS composites 98 
4.3.5 Determination of tensile properties 98 
4.3.6 Water absorption and biodegradability of MPETS 98 
composites 
4.3.7 Determination of weatherability of MPETS 104 
composites 111 
4.4 C O N C L U S I O N S 113 
C H A P T E R F I V E 114 
5.1 F U T U R E W O R K 115 
5.2 L I S T O F R E F E R E N C E S 116 
/ 
i 
xiii 
• 
L I S T O F T A B L E S 
Page No 
Table 2.1 Different types of lignocellulosic fillers used in the 9 
polymeric composites 
Tab le 2.2 Infrared peak assignments for LDPE, straw powder and 
PES composite 28 
Tab le 2.3 Tensile properties of LDPE and PES composites 39 
Tab le 2.4 Variation in tensile properties of LDPE and PES 
composites after weathering process 48 
Tab le 3.1 Tensile properties of different maleated LDPE samples. 66 
Tab le 3.2 Infrared vibrations and assignment for PES composite, 
maleated LDPE and MPES composite 67 
Tab le 3.3 Tensile properties of maleic grafted LDPE and MPES 
composites 76 
Tab le 3.4 Variation in tensile properties of MPES composites after 
weathering process 85 
Tab le 4.1 Infrared vibrations and assignment for straw powder 95 
Tab le 4.2 Chemical analysis of components in rice-straw 96 
Tab le 4.3 Tensile properties of maleic grafted LDPE and MPETS 
composites 103 
Tab le 4.4 Variation in tensile properties of MPETS composites 
after weathering 112 
• 
xiv 
L I S T O F F I G U R E S 
Page No. 
Figure 1.0 Schematic representation of cellulose 11 
F igure 1.1 Schematic representation of hemicellulose 11 
F igure 1.2 Schematic representation of three basic building 
blocks of lignin 12 
F igu re 2.0 FTIR spectra of a) Rice Straw b) LDPE c) PES 
composites 29 
F igure 2.1 (a) Stress-strain curve for LDPE 31 
F igure 2.1 (b) Stress-strain curves for ( • ) PES-50-5, (©) PES-
50-10 and ( A ) PES-50-15 composites 32 
F igure 2.1 (c) Stress-strain curves for ( • ) PES-90-5, ( • ) PES-
90-10 and ( A ) PES-90-15 composites 33 
F igu re 2.1 (d) Stress-strain curves for ( • ) PES-250-5, (©) 
PES-250-10 and ( A ) PES-250-15 composites 34 
F igu re 2.2 (a) Stress-strain curves of different PES composites 
having 5%wt of straw. ( • ) PES-50-5, ( • ) PES-
90-5 and ( A ) PES-250-5 composites 35 
F igu re 2.2 (b) Stress-strain curves of different PES composites 
having 10 %wt of straw. ( • ) PES-50-10, ( • ) 
PES-90-1 Oand ( A ) PES-250-10 composites 36 
xv 
Figure 2.2 (c) Stress-strain curves of different PES composites 
having 15 %wt of straw. ( • ) PES-50-15, ( • ) PES-
90-15and ( A ) PES-250-15 composites 
37 
F igure 2.3 (a) Variation in tensile strength vs straw content for ( • ) 
PES-50, ( • ) PES-90 and ( A ) PES-250 composites 38 
F igure 2.3 (b) Variation in % elongation vs straw content for ( • ) 
PES-50, ( • ) PES-90 and ( • ) PES-250 composites 39 
F igure 2.3 (c) Variation in Young's modulus vs straw content for 
( • ) PES-50, ( • ) PES-90 and ( A ) PES-250 
composites 40 
F igure 2.4 Percentage weight change of ( • ) PES-50-5, ( • ) PES-
50-15, ( * ) PES-90-15 and ( • ) PES-250-15 composites 
during immersion in water 46 
F igure 3.0 Schematic representation of Maleic anhydride 53 
F igure 3.1 Decomposit ion reaction of DCP 54 
F igure 3.2 Formation of LDPE macro radical 54 
F igure 3.3 Grafting of maleic anhydride on LDPE backbone 55 
Figure 3.4 Transfering step of macro radical in to LDPE backbone 55 
F igure 3.5 Formation of covalent interaction between maleated 
LDPE and OH of cellulose 57 
F igure 3.6 FTIR spectra of Maleic anhydride grafted LDPE and 
virgin LDPE 63 
xvi 
Figure 3.7 Melt viscosity and shear rate behavior of ( • ) LDPE, 
( • ) LDPE + 0.05% DCP + 5% MA, ( A ) LDPE+ 0.25% 
DCP + 5% MA, ( _ ) LDPE + 0.4% D C P + 5 % M A and 
( • ) LDPE + 0.4% DCP samples 65 
Figure 3.8 FTIR spectra of (a) Maleic anhydride grafted LDPE, (b) 
PES composite and (c) MPES composite 68 
F igu re 3.9(a) Stress-strain curves for ( • ) MPES 50-5, ( • ) MPES 
50-10 and ( A ) MPES 50-15 composites 70 
F igu re 3.9(b) Stress-strain curves for ( • ) MPES 90-5, ( • ) MPES 
90-10 and ( A ) MPES 90-15 composites 71 
F i g u r e 3.9(c) Stress-strain curves for ( • ) MPES 250-5, ( • ) MPES 
250-10 and ( A ) MPES 250-15 composites 72 
F igu re 3.10(a) Stress-strain curves of different MPES composites 
having 5%wt of straw. ( • ) MPES-50-5, ( • ) M P E S -
90-5 and ( A ) MPES-250-5 composites 73 
F igure 3.10(b) Stress-strain curves of different MPES composites 
having 10 %wt of straw. ( • ) MPES-50-10, ( • ) 
MPES-90-10and ( A ) MPES-250-10 composites 74 
F igure 3.10(c) Stress-strain curves of different MPES composites 
having 15 %wt of straw ( • ) MPES-50-15, ( • ) 
MPES-90-15and ( A ) MPES-250-15 composites 75 
F igu re 3.11(a) Variation in tensile strength vs straw content for ( • ) 
MPES-50, ( • ) MPES-90 and ( A ) MPES-250 
composites 79 
Figure 3.11(b) Variation in Young's modulus vs straw content for 
( • ) MPES-50, ( • ) MPES-90 and ( • ) MPES-250 
composites 80 
Figure 3.11(c) Variation in % elongation vs Straw Content for ( • ) 
MPES-50, ( • ) MPES-90 and ( A ) MPES-250 
composites 81 
Fig 3.12 Melt viscosity and shear rate behavior of MPES composite 
( • ) MPES 50-15 and ( • ) PES50-15 composite 83 
Fig 3.13 Percentage weight change of ( • ) MPES 50-5, ( • ) MPES 
50-15, ( * ) MPES 90-15 a n d . ( « ) MPES 250-15 
composites during immersion in water. 86 
F igure 4.0 FTIR spectra of (a) Treated Straw and (b) Untreated 
Straw 97 
F igure 4.1 FTIR spectra of (a) MPETS and (b) MPES Composite 99 
F igure 4.2(a) Stress-strain curves for ( • ) MPETS 50-5, ( • ) 
MPETS 50-10 and ( A ) MPETS 50-15 composites 100 
Figure 4.2(b) Stress-strain curves for ( • ) MPETS 90-5, ( • ) 
MPETS 90-10 and ( A ) MPETS 90-15 composites 101 
F igure 4.2(c) Stress-strain curves for ( • ) MPETS 250-5, ( • ) 
MPETS 250-10 and ( A ) MPETS 250-15 composites 102 
Figure 4.3(a) Variation in tensile strength vs straw content for ( • ) 
MPETS-50, ( • ) MPETS-90 and ( A ) MPETS-250 
composites 105 
XVlii 
Figure 4.3(b) Variation in Young's modulus vs straw content for 
( • ) MPETS-50, ( • ) MPETS-90 and ( A ) MPETS-
250 composites 
F igure 4.3(c) Variation in % elongation vs straw content for ( • ) 
MPETS-50, ( • ) MPETS-90 and ( • ) MPETS-250 
composites 
F igure 4.4(a) Variation in tensile strength of different composites 
for ( • ) PES 50 series, ( • ) MPES 50 series and ( A ) 
MPETS 50 series composites 
F igure 4.4(b) Variation in Young's modulus of different 
composites for ( • ) PES 50 series, ( • ) MPES 50 
series and ( A ) MPETS 50 series 
Fig 4.5 Percentage weight change of ( • ) MPETS 50-5, ( • ) 
MPETS 50-15, ( * ) MPETS 90-15 and (©) MPETS 
250-15 composites during immersion in water 
L I S T O F A B B R E V I A T I O N S 
ecu . Carbon tetra Chloride 
C a C 0 3 - Calcium Carbonate 
DCP - Dicumyl Peroxide 
DP - Degree of Polymerization 
FTIR - Fourier Transform Infra- Red 
KBr - Potasium Bromide 
HDPE - High Density Polyethylene 
LDPE/PE - Low Density Polyethylene 
MA - Maleic Anhydride 
MPa - Mega Pascal 
MPETS - Maleated LDPE/Treated straw composite 
MPES - Maleated LDPE/Un Treated straw composite 
.NaOH - Sodium hydroxide 
PES - LDPE/Un Treated rice-straw composite 
PMPPIC - Poly[methylene (poly (phenyl isocyanate))] 
PP - Polypropylene 
PS - Polystyrene 
PVC - Polyvinyl Chloride 
rpm - Rounds per minutes 
TAPPI - Technical Association for Pulp And Paper Industry 
TDIC - Toluene2, 4- diisocyanate 
% T - Percentage transmittance 
UV - Ultraviolet radiation 
W t % - Weight percentage 
3-D - Three dimensional 
XX