UNIVERSITI PUTRA MALAYSIA
PERFORMANCE OF IRRADIATED AND CROSSLINKED ETHYLENE
VINYL ACETATE-WASTE TIRE DUST BLEND
ANIS SAKINAH BINTI ZAINAL ABIDIN
FK 2009 36
PERFORMANCE OF IRRADIATED AND CROSSLINKED ETHYLENE VINYL ACETATE-WASTE TIRE DUST BLEND
By
ANIS SAKINAH BINTI ZAINAL ABIDIN
Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia, in Fulfilment of the Requirement for the Degree of Master of
Science
April 2009
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DEDICATION
This work is dedicated to my beloved parents and family for their endless love, patience and support.
My Parents and family
SADIAH BAHAROM, ZAINAL ABIDIN, SUMAIYA, IRFAN, ZUHAIR, ATIFA
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Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfilment of the requirement for the degree of Master of Science
PERFORMANCE OF IRRADIATED AND CROSSLINKED ETHYLENE VINYL ACETATE-WASTE TIRE DUST BLEND
By
ANIS SAKINAH BINTI ZAINAL ABIDIN
April 2009
Supervisor : Luqman Chuah Abdullah, PhD
Faculty : Engineering
The influences of electron beam irradiation, addition of crosslinking agents and
the combination of irradiation and crosslinking agents on the properties of
Ethylene Vinyl Acetate/Waste Tire Dust (EVA/WTD) blends were investigated.
Trimethylolpropane triacrylate (TMPTA) and tripropyleneglycol diacrylate
(TPGDA) were chosen as crosslinking agents. Blends were prepared by melt
mixing in an internal mixer, Haake Rheomix Polydrive R600/610 at
temperature and rotor speed of 140oC and 50 rpm, respectively. Studies in
processing conditions were carried out in order to ensure the enhancement of
EVA/WTD blend properties through irradiation. Results revealed that the
optimum processing conditions were at 140oC mixing temperature, with 10 min
of blending time and at 90/10 (EVA/WTD) blend ratio. The dynamic
mechanical properties showed two glass transition temperatures that indicates
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incompatible blends. The introduction of electron beam irradiation on
EVA/WTD at different doses, 50, 100, 150 and 200 kGy has enhanced the
irradiation-induced crosslinking. Irradiation-induced crosslinking has increased
with the increase in irradiation dose and lead to the improvement in tensile
properties, compatibility, dynamic and thermal mechanical properties of the
blends. The incorporation of TMPTA and TPGDA as crosslinking agents lead
to the improvement of tensile strength, thermal and dynamic mechanical
properties. A decline in tensile strength and dynamic properties of the
EVA/WTD blend at above 50 kGy irradiation dose in the presence of TMPTA
was observed. Such a decrease attributed to the embrittlement of the blend due
to high extent of irradiation-induced crosslinking. TPGDA was found to serve
the optimum tensile and dynamic mechanical properties upon EB irradiation of
EVA/WTD blends.
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Abstrak tesis ini dikemukakan kepada Senat Universiti Putra Malaysia bagi memenuhi syarat-syarat untuk memperolehi Ijazah Sarjana Sains
PRESTASI ADUNAN ETILINA VINIL ACETAT-SERBUK TAYAR TERBUANG TERSINAR DAN BERANGKAI SILANG
Oleh
ANIS SAKINAH BINTI ZAINAL ABIDIN
April 2009
Penyelia : Luqman Chuah Abdullah, PhD
Fakulti : Kejuruteraan
Kesan radiasi alur elektron dan agen sambung silang serta gabungan kedua-
duanya ke atas sifat-sifat adunan etilina vinil acetat/serbuk tayar terbuang
(EVA/WTD) telah dikaji. Trimethylolpropane triacrylate (TMPTA) dan
tripropyleneglcol diacrylate (TPGDA) telah dipilih sebagai agen sambung
silang. Adunan disediakan dengan menggunakan pencampur dalaman Haake
Rheomix Polydrive R600/610 pada suhu 140oC dan kelajuan rotor 50 rpm.
Kajian terhadap proses pembuatan adunan telah dijalankan bagi memastikan
sifat-sifat adunan EVA/WTD akan lebih baik apabila menjalani radiasi.
Keputusan menunjukkan bahawa proses pembuatan adunan EVA/WTD yang
optimum perlu dijalankan pada suhu 140oC bagi suhu pengadunan dan 10 min
bagi masa pengadunan serta berkomposisi 90/10 EVA/WTD. Sifat-sifat
mekanik dinamik menunjukkan adunan adalah tidak serasi kerana terdapat dua
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suhu peralihan kaca. Dengan mengenakan radiasi alur elektron ke atas adunan
EVA/WTD pada dos yang berbeza iaitu 50, 100, 150 and 200 kGy, telah
meningkatkan sambung silang adunan. Sambung silang yang dipengaruhi oleh
radiasi meningkat dengan peningkatan dos radiasi dan menyebabkan
peningkatan pada sifat-sifat tensil, keserasian, sifat-sifat mekanikal dinamik,
dan sifat-sifat terma adunan. Penggunaan agen sambung silang seperi TMPTA
dan TPGDA telah meningkatkan lagi sambung silang ini dalam kekuatan tensil,
sifat-sifat terma dan sifat-sifat mekanikal dinamik. Pada dos radiasi 50 kGy,
dengan kehadiran agen sambung silang, penurunan pada kekuatan tensil dan
mekanikal dinamik berlaku. Ini adalah kerana peningkatan sambung silang yang
berlebihan telah menyebabkan adunan menjadi rapuh. TPGDA didapati paling
berkesan dalam meningkatkan sambung silang yang dipengaruhi oleh radiasi.
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ACKNOWLEDGEMENTS
Syukur Alhamdulillah to The Almighty God for His shower of blessing, I am
able to complete this study within the time given to me.
I wish to express my sincere and deep gratitude to my Supervisor Assoc. Prof.
Dr. Luqman Chuah Abdullah (UPM), my co-supervisors, Assoc. Prof. Dr.
Thomas Choong Shean Yaw and Dr. Chantara Thevy Ratnam (MNA) for their
invaluable ideas, guidance, patience and support which have contributed to the
success of this thesis. Without their help in sharing of comments and opinions,
this study would not have seen the light of day.
I would also like to forward my gratitude to technical staff namely Mr. Wan Ali
Wan Yusof, Mr. Zahid Abdullah and Mr. Kamarulzaman the technical staff at
MNA.
My special appreciation goes to my friends Jenney, Fatimah, Nik, Nad, Emi,
Aiza Syuhaniz, Zalinda, Alifah and Hayuti for their encouragement through this
research work.
Last but not least, I would like to thank all the professors and lecturers from
Department of Chemical and Environment Engineering especially Dr. Dayang
Awang Biak and those who had helped me directly and indirectly in order to
improve and complete this thesis.
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I certify that the Examination Committee has met on 16 April 2009 to conduct the final examination of Anis Sakinah binti Zainal Abidin on her thesis entitled “Performance of Irradiated and Crosslinked Ethylene Vinyl Acetate-Waste Tire Dust Blend” in accordance with the Universities and University Colleges Act 1971 and the Constitution of the Universiti Putra Malaysia [P.U.(A) 106] 15 March 1998. The Committee recommends that the student be awarded the Master of Science. Members of the Examination Committee were as follows: Salmiaton Ali, PhD Associate Professor Faculty of Engineering Universiti Putra Malaysia (Chairman) Mohamad Amran Mohd. Salleh, PhD Lecturer Faculty of Engineering Universiti Putra Malaysia (Internal Examiner) Siti Aslina Hussain, PhD Lecturer Faculty of Engineering Universiti Putra Malaysia (Internal Examiner) Abdul Razak Rahmat, PhD Associate Professor Faculty of Chemical and Natural Resources Engineering, Universiti Teknologi Malaysia (External Examiner) BUJANG KIM HUAT, PhD Professor and Deputy Dean School of Graduate Studies Universiti Putra Malaysia Date:13 July 2009
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This thesis submitted to the Senate of Universiti Putra Malaysia and has been accepted as fulfilment of requirement for the degree of Master of Science. The members of supervisory Committee are as follows: Luqman Chuah Abdullah, PhD Associate Professor Faculty of Engineering Universiti Putra Malaysia (Chairman) Thomas Choong Shean Yaw,PhD Associate Professor Faculty of Engineering Universiti Putra Malaysia (Member) Chantara Thevy Ratnam Senior Research Officer Malaysia Nuclear Agency (Member) HASANAH MOHD. GHAZALI, PhD Professor and Dean School of Graduate Studies Universiti Putra Malaysia Date: 13 July 2009
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DECLARATION I hereby declare that the thesis is based on my original work except for quotations and citations, which have been duly acknowledged. I also declare that it has not been previously or concurrently submitted for any other degree at UPM or other institutions. ANIS SAKINAH ZAINAL ABIDIN Date:
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TABLE OF CONTENTS DEDICATION ii ABSTRACT iii ABSTRAK v ACKNOWLEDGEMENTS vii APPROVAL viii DECLARATION x LIST OF TABLES xiv LIST OF FIGURES xv LIST OF SYMBOLS xix LIST OF ABBREVIATION xx CHAPTER 1 INTRODUCTION
1.1 Background of study 1 1.2 Problems Statement 3 1.3 Objective of the study 4 1.4 Research Scope 5
2 LITERATURE REVIEW 2.1 Polymer Blends 6 2.2 Thermoplastic Elastomer (TPEs) Blends 8 2.2.1 Thermoplastic 10 2.2.2 Ethylene Vinyl Acetate (EVA) 10 2.2.3 Waste Tire Dust (WTD) 13 2.3 Radiation 16 2.4 Coagent 18 2.5 Miscibility 20 2.6 Crystallinity 21 2.7 Thermal transition in polymer (Tg and Tm) 23 2.8 Characterization and properties of Polymer Blends 25 2.8.1 Morphological of polymer blends 25 2.8.2 Mechanical Properties of Polymer Blends 26 2.8.3 Dynamic Mechanical Analysis (DMA) 29 2.8.4 Differential Scanning Calorimetry (DSC) 31 3 MATERIALS, EQUIPMENTS AND EXPERIMENTAL PROCEDURES 3.1 Material 34 3.1.1 Waste Tire Dust(WTD) 34 3.1.2 Ethylene Vinyl Acetate (EVA) 35
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3.1.3 Crosslinking agent/Coagent 35 3.2 Experimental Procedures 36 3.2.1 Mixing Process 36 3.2.2 Compression Molding and Cool Press 37 3.2.3 Irradiation 38 3.3 Preliminary Studies 38 3.4 Measurements and Characterization 39 3.4.1 Tensile test 40 3.4.2 Hardness test 40 3.4.3 Morphology Study (SEM) 40 3.4.4 Gel Content 41 3.4.5 Dynamic Mechanical Analysis (DMA) 41 3.4.6 Differential Scanning Calorimetry (DSC) 42 4 RESULTS AND DISCUSSIONS 4.1 Introduction 43 4.2 Optimization Process 43 4.2.1 Effect of temperature of EVA/WTD blend at 70/30 blend ratio 44 4.2.2 Effect of blending time of 70/30 EVA/WTD blends 47 4.2.3 Effect of blend ratio of EVA/WTD blends 48 4.3 Effect of irradiation of EVA/WTD blends 52 4.3.1 Tensile properties 52 4.3.2 Scanning Electron Microscope (SEM) 55 4.3.3 Dynamic Mechanical Properties (DMA) 57 4.3.4 Differential Scanning Calorimetry (DSC) 65 4.4 Effect of crosslinking agent on EVA/WTD blends 67 4.4.1 Scanning Electron Microscope (SEM) 67 4.4.2 Dynamic Mechanical Analysis (DMA) 69 4.4.3 Differential Scanning Calorimetry (DSC) 71 4.5 Combine effect of irradiation and crosslinking agent on EVA/WTD blends 72 4.5.1 Gel content analysis 73 4.5.2 Tensile properties 74 4.5.3 Hardness properties 78 4.5.4 Scanning Electron Microscope (SEM) 79 4.5.5 Dynamic Mechanical Analysis (DMA) 82 4.5.6 Differential Scanning Calorimetry (DSC) 88 5. CONCLUSION AND RECCOMENDATION 5.1 Conclusion 91 5.2 Recommendations 93
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REFERENCES 94 APPENDICES 101 BIODATA OF STUDENT 102 LIST OF PUBLICATIONS 103
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LIST OF TABLES
3.1 Product specification of WTD 34
3.2 Product specification of EVA 35
3.3 Processing parameter in compression molding and cool press of EVA/WTD blends. 38
4.1 Effect of blending time on tensile properties of 70/30 EVA/WTD blends 48
4.2 Dynamic mechanical properties of EVA/WTD blends at different blend ratios (0 kGy) 57
4.3 Dynamic mechanical properties of EVA/WTD blends at different blend ratios (200 kGy) 57
4.4 Tg and Tan delta maximum (damping maximum) values of EVA/WTD blend at 90/10 blend at different irradiation doses 62
4.5 Thermal properties of 90/10 EVA/WTD blends at different irradiation doses 65
4.6 Tg and tan delta maximum (damping maximum) values of EVA/WTD 90/10 blend 69
4.7 Thermal properties of 90/10 EVA/WTD blends with and without crosslinking agent 71
4.8 Tg values of EVA/WTD at 90/10 blend and the components at different irradiation doses 82
4.9 Tan delta maximum (damping maximum) of EVA/WTD at 90/10 blend and the components at different irradiation doses. 83
4.10 Thermal properties of 90/10 EVA/WTD blends with crosslinking agent at different irradiation doses 88
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LIST OF FIGURES
2.1 The molecular structure of EVA copolymer 11
2.2 Components of tires 14
2.3 Interaction of multifunctional acrylate with polymer radical by irradiation 19
2.4 General types of stress-strain curve 27
2.5 Typical DMA curve for polymer 31
2.6 DSC thermogram 33
3.1 Chemical structure of TPGDA 36
3.2 Chemical structure of TMPTA 36
3.3 Haake Rheomix Polydrive R600/610 internal mixer 37
4.1 Torque time curve of EVA/WTD blend at different blending temperature 45
4.2 The effect of temperature on tensile strength and M100 of EVA/WTD blends 46
4.3 The effect of temperature on elongation at break of EVA/WTD blends 47
4.4 Torque time curve of EVA/WTD blend at different blend ratios for 140oC and 10 min 49
4.5 Effect of blend ratios at (A) 120oC and (B) 140oC on tensile strength of EVA/WTD blends 50
4.6 Effect of blend ratios at (A) 120oC and (B) 140oC on elongation at break of EVA/WTD blends 51
4.7 Effect of blend ratios at (A) 120oC and (B) 140oC on M100 of EVA/WTD blends 51
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4.8 Effect of blend ratios and irradiation on tensile properties of EVA/WTD blends 54
4.9 Effect of blend ratios and irradiation on elongation at break of EVA/WTD blends 54
4.10 Effect of blend ratios and irradiation on modulus 100 of EVA/WTD blends 55
4.11 SEM Morphology of tensile fracture surface of 90/10 EVA/WTD blend (a) 0kGy (b) 100kGy (c) 200kGy. (500x) 56
4.12 The temperature dependence of tanδ of different blend ratios at 0 kGy 59
4.13 The temperature dependence of tanδ of different blend ratios at 200 kGy 60
4.14 Temperature dependence of storage modulus for difference blend ratios at 0 kGy 61
4.15 Temperature dependence of storage modulus for difference blend ratios at 200 kGy 61
4.16 Tan delta as a function of temperature for 90/10 EVA/WTD blend without crosslinking agent at different irradiation doses 63
4.17 Storage modulus as a function of temperature for 90/10 EVA/WTD blend without crosslinking agent at different irradiation doses 64
4.18 Differential scanning calorimety curve for 90/10, WTD/EVA at different radiation doses 66
4.19 SEM morphology of tensile fracture surface of 90/10, EVA/WTD blend with presence of crosslinking agent (a) control (b) TMPTA (c) TPGDA (500x) 68
4.20 Tan delta as a function of temperature for 90/10 EVA/WTD blend with and without crosslinking agent 70
4.21 Storage modulus as a function of temperature for 90/10 EVA/WTD blend with and without crosslinking agent 70
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4.22 Differential scanning calorimety curve for 90/10, EVA/WTD blends at different radiation doses 72
4.23 The effect of crosslinking agents on gel content of 90/10 EVA/WTD blend at different irradiation doses 74
4.24 The effect of crosslinking agents on tensile strength of 90/10 EVA/WTD blend at different irradiation doses 77
4.25 The effect of crosslinking agents on elongation at break of 90/10 EVA/WTD blend at different irradiation doses 77
4.26 The effect of crosslinking agents on M100 of 90/10 EVA/WTD blend at different irradiation doses 78
4.27 Effect of crosslinking agents on hardness properties of 90/10 EVA/WTD blend at different irradiation dose 79
4.28 SEM Morphology of tensile fracture surface of 90/10 EVA/WTD blend with the present of TMPTA (a) 0kGy (b) 100kGy (c) 200kGy. (500x) 80
4.29 SEM Morphology of tensile fracture surface of 90/10 EVA/WTD blend with the present of TPGDA 81
4.30 Tan delta as a function of temperature for 90/10 EVA/WTD blend without crosslinking agent at different doses 84
4.31 Tan delta as a function of temperature for 90/10 EVA/WTD blend with and TMPTA presence at different doses 85
4.32 Tan delta as a function of temperature for 90/10 EVA/WTD blend with and TPGDA presence at different doses 85
4.33 Storage modulus as a function of temperature for 90/10 EVA/WTD blend without crosslinking agent at different doses 85
4.34 Storage modulus as a function of temperature for 90/10
EVA/WTD blend with with TMPTA presence at different doses 87
4.35 Storage modulus as a function of temperature for 90/10
EVA/WTD blend with with TPGDA presence at different doses 87
86
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4.36 Differential scanning calorimetry curve for 90/10 EVA/WTD blend with TPGDA at different irradiation doses 90
4.37 Differential scanning calorimetry curve for 90/10 EVA/WTD blend with TMPTA at different irradiation doses 90
LIST OF SYMBOLS
Tg Glass transition temperature
Tm Melting temperature
ΔHf Heat of fusion
Xc Degree of crystallinity
oC Degree Celsius
kGy Kilo Gray
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LIST OF ABBREVIATION
phr Part per hundred rubber
rpm Revolution per minutes
wt% Weight percentage
ABS Acrylonitrile butadiene styrene
ASTM American Society for Testing and Material
BrTFF 2-bromotetraflouroethyl trifluorovinyl ether
cPTFE poly(tetrafluoroethylene)
DCP dicumyl peroxide
DMA Dynamic mechanical analysis
DSC Differential scanning calorimetry
EB Electron beam
ENR Epoxidized natural rubber
EPDM Ethylene propylene diene terpolymer
EVA Ethylene vinyl acetate
HDPE High-density polyethylene
HIPS High impact polystyrene
HVA-2 N,N-m phenylene dimaleimide
LDPE Low-density polyethylene
MFI Melt flow index
MIDA Malaysia Industrial Development Authority
NBR Nitrile rubber
NR Natural rubber
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PC Polycarbonate
PE Polyethylene
PP Polypropylene
PU polyurethane
PVC Polyvinyl chloride
RMA Rubber modified asphalt
RPE recycle polyethylene
SBR Styrene butadiene rubber
SEM Scanning electron microscope
TMPTA Trimethylolpropane triacrylate
TPE Thermoplastic elastomer
TPGDA Tripropyleneglycol diacrylate
UV Ultra violet
VA Vinyl acetate
VPFESEM Variable pressure field emission scanning electron microscope
WTD Waste tire dust
XBR Carboxylated nitrile rubber
CHAPTER 1
INTRODUCTION
1.1 Background of study
The production of tire is increasing every year due to the increase of vehicle
sales, where tire is an integral part of vehicle. The generation and disposal of
waste are inherent to life itself and have presented problems to the human
community. Data from the Malaysia Industrial Development Authority (MIDA)
shows that Malaysia generates about 150,000 tons of scrap tires every year.
Although there are low performance uses for granulated scrap tire rubber, and
small amounts of powder are used in the production of new tires, demand has
been limited because the relatively large particle sizes produced commercially
are expensive and do not compound well (Wendy, 2008). Waste tire rubber can
be blended with thermoplastics to produce thermoplastic elastomers with a
range of properties. Thermoplastic elastomers (TPE) have physical properties of
both thermoplastic and elastomer as well as similar processability to that of
thermoplastics. TPE provides better material utilization, as scrap and rejects can
be recycled.
These materials can be used in conventional thermoplastics processing
equipment. The unique characteristics of thermoplastic elastomer make them an
attractive alternative to conventional elastomers in a variety of markets such as
2
the automotive industry. The potential to convert a conventional elastomer
(thermoset) into thermoplastic elastomer through blending offers the potential
for new market applications for waste tire dust (WTD). Several studies have
been done by blending WTD with polypropylene (PP) (Ismail et al., 2006), high
density polyethylene (HDPE) and low density polyethylene (LDPE) (Sonnier et
al., 2007), recycle polyethylene (RPE) (Scaffaro et al., 2005) and natural rubber
(NR) (Ismail et al., 2002). In their work, they found that recycle tires behave as
filler with relatively low interaction with the matrix without any additives.
Therefore, a study of the influence of electron beam irradiation and crosslinking
agent were done in attempt to improve the compatibility and enhance the
properties of the ethylene vinyl acetate (EVA)/WTD blend. High energy
irradiation (gamma and electron beam) is a well known technique for the
modification of polymers (Makhlis, 1972). It causes molecular changes in
polymer resulting chain crosslinking, chain scission, grafting and curing. As the
irradiation doses increase, chains in the polymer network will undergo further
crosslink until it produce high crosslink density. Chain crosslink may enhance
the tensile strength, elongation, modulus and hardness, while chain scission
decreases these properties (Scaffaro et al., 2005).
EVA are random structured polymers which offer excellent ozone resistance,
weather resistance and mechanical properties (Sujit, 1996). EVA also is a
halogen free thermoplastic which may suit many applications that are currently
3
dominated by plasticized poly(vinyl chloride) (PVC) (Zurina et al., 2008). It
has good clarity and gloss, barrier properties, low-temperature toughness,
stress-crack resistance, hot-melt adhesive and heat sealing properties and
resistance to ultra violate (UV) radiation. EVA is used as wire and cable
coating, flexible tubing, shoe soles, food packaging and impact modifier
(Zurina, 2007). Thus, making it suitable in formulation of thermoplastic
elastomer (Zurina et al., 2006a)
1.2 Problems Statement
The problems associated with disposal of the vast number of scrap tires
produced annually worldwide are very clear. The durability of tires and the time
it takes them to degrade makes them suitable for long term applications (Al-
Tabbaa et al., 2001). A potential re-use of waste tire dust, which has received a
lot of attention, can be use as filler in polymer compound. However, waste tire
dust has low properties, as it is a used material which causes weak interaction
between the ethylene vinyl acetate and waste tires dust component. Thus,
variety of modification techniques has been done to improve the compatibility
between the immiscible blend components. The modification technique that
have been chosen are radiation induce using electron beam accelerator and
adding crosslinking agent in the blend. Radiation and crosslinking agent effect
for EVA/WTD blend in researching for compatibility and improving properties
of the blend are the principle problems that paving the track of this thesis work.