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

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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

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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.