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UNIVERSITI PUTRA MALAYSIA

EFFECTS OF GRAFTING ON KENAF FIBER REINFORCED POLY VINYL CHLORIDE/ETHYLENE VINYL ACETATE BLEND

COMPOSITES

NURFATIMAH BINTI ABU BAKAR

IPTPH 2011 2

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EFFECTS OF GRAFTING ON KENAF FIBER REINFORCED POLY

VINYL CHLORIDE/ETHYLENE VINYL ACETATE BLEND COMPOSITES

By

NURFATIMAH BINTI ABU BAKAR

Thesis submitted to the school of Graduate Studies, Universiti Putra Malaysia,

in Fullfilment of the Requirements for the Degree of Master of Science

June 2011

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This work is dedicated to:

My husband: Mohd Adzhar bin Ismail,

My son: Muhammad Anas Haqimi,

ibu, abah,

and

my big family

Thank you for provided constructive advice for the completion of this thesis. I also

appreciate for their love, support, understanding and patience.

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Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfillment

of the requirement for the degree of Master of Science

EFFECTS OF GRAFTING ON KENAF FIBER REINFORCED POLY VINYL

CHLORIDE/ETHYLENE VINYL ACETATE BLEND COMPOSITES

By

NURFATIMAH ABU BAKAR

June 2011

Chairman : Associate Professor Luqman Chuah Abdullah, PhD

Institute : Institute of Tropical Forestry and Forests Product

Kenaf fiber is an environmentally friendly alternative which can be used as important

reinforcing filler for thermoplastic composites. Kenaf also can be a good potential to

make significant contribution. The main objective of this works is to investigate the

possibility of producing new composites with methyl methacrylate (MMA) grafted

kenaf as filler by using poly (vinyl chloride)/ethylene vinyl acetate as a polymer matrix.

Graft copolymerization of methyl methacrylate (MMA) onto kenaf fiber has been

carried out. Response surface methodology (RSM) based on centre composite design

(CCD) was used to evaluate the effects of process variables (temperature, reaction time

and amount of hydrogen peroxide) and their interaction towards the attainment of their

optimum condition (grafting percentage). According to statistical analysis, the grafting

reaction model proved to be highly significant with a very low probability value

(<0.0001). The optimum condition (Pg = 51.85%) obtained at the temperature of 60oC,

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reaction time, 112 min and the amount of hydrogen peroxide is 7 mL. The presence of

the functional group in the grafted polymers was characterized by fourier transform

infrared (FTIR) spectroscopy. Scanning electron microscopy (SEM) also confirmed the

presence of poly methyl methacrylate (PMMA) on the surface of kenaf fiber. Effect of

kenaf fiber and kenaf-g-PMMA on mechanical properties of poly (vinyl chloride)

(PVC)/ethylene vinyl acetate (EVA) blend were studied. The composites were prepared

by blending using HAAKE Rheomixer Polydrive R600/610 at temperature and rotor

speed of 150oC and 50 rpm. Effect of different fiber loading (0%, 10%, 15%, 20% and

30%) on their tensile strength, tensile modulus, flexural modulus, impact strength and

hardness were determined. An increasing trend was observed in the tensile modulus,

flexural modulus and hardness while a slight decrease was observed in tensile strength

and impact strength was decreased. This observation indicates that grafting PMMA on

the surface of kenaf fiber was improved the interfacial adhesion between the matrix and

fiber. Differential Scanning Calorimetric (DSC) results show that the EVA

crystallization behaviour is significantly influenced by the presence of kenaf fiber. The

incorporation of grafted and ungrafted kenaf did not affect the thermal stability of the

composites. Dynamic mechanical analysis (DMA) showed an increase in the storage

modulus of the grafted composites.

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Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai

memenuhi keperluan untuk ijazah Master Sains

KESAN CANGKUKAN KE ATAS GENTIAN KENAF DALAM KOMPOSIT

ADUNAN POLI VINIL KLORIDA/ETILINA VINIL ASETAT

Oleh

NURFATIMAH ABU BAKAR

June 2011

Pengerusi : Profesor Madya Luqman Chuah Abdullah, PhD

Institut : Institut Perhutanan Tropika dan Produk Hutan

Gentian kenaf adalah salah satu alternatif mesra alam di mana ia boleh digunakan

sebagai pengisi dalam komposit termoplastik. Kenaf juga berpotensi untuk memberi

sumbangan yang signifikan. Tujuan utama kajian ini adalah untuk mengkaji

kemungkinan menghasilkan komposit baru dengan metil metakrilat (MMA)

dicangkokkan ke atas gentian kenaf dengan menggunakan adunan poli vinil klorida

(PVC) / etilina vinil asetat (EVA) sebagai matrik polimer. Pengkopolimeran cangkuk

metil metakrilat (MMA) kepada gentian kenaf telah dilakukan. RSM jenis rekabentuk

komposit pusat (CCD) digunakan untuk menilai kesan pembolehubah proses (suhu,

masa tindakbalas dan jumlah hidrogen peroksida) dan hubungan mereka pada keadaan

optima (peratusan cangkukan). Berpandukan analisis statistik, model reaksi cangkukan

terbukti sangat signifikan dengan nilai kebarangkalian sangat rendah (<0,0001).

Keadaan optima (Pg = 51.85%) diperolehi pada suhu 60oC, masa tindakbalas berlaku,

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112 minit dan jumlah hidrogen peroksida adalah 7 mL. Kehadiran kumpulan berfungsi

dalam cangkokan polimer dapat dikesan oleh FTIR. SEM juga menjelaskan adanya poli

(metil metakrilat) (PMMA) pada permukaan gentian kenaf. Kesan gentian kenaf dan

gentian kenaf yang telah dicangkukkan dengan PMMA terhadap sifat mekanikal adunan

PVC/EVA telah dikaji. Komposit adunan telah disediakan dengan menggunakan

pencampur dalaman HAAKE Polydrive R600/610 pada suhu 150oC dan kelajuan rotor

50 rpm. Kesan campuran gentian yang berbeza (0%, 10%, 15%, 20% dan 30%) pada

kekuatan tegangan, modulus tegangan, modulus keterlenturan, kekuatan hentaman dan

kekerasan telah dikaji. Keputusan menunjukkan peningkatan di modulus tegangan,

modulus keterlenturan dan kekerasan manakala sedikit penurunan pada kekuatan

tegangan dan kekuatan hentaman. Ini menunjukkan bahawa cangkukan PMMA pada

permukaan gentian kenaf dapat meningkatkan lekatan permukaan antara matrik dan

gentian. Keputusan DSC menunjukkan penghabluran EVA adalah dipengaruhi oleh

isian gentian kenaf. Campuran gentian kenaf dan gentian kenaf yang telah

dicangkukkan dengan PMMA tidak memberi kesan kepada kestabilan terma komposit.

DMA menunjukkan peningkatan modulus penyimpanan pada gentian kenaf yang telah

dicangkukkan dengan PMMA.

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ACKNOWLEDGEMENTS

Syukur Alhamdulillah to The Almighty God for His shower of blessing, I am able to

complete this study.

I would like to express my sincere gratefulness and appreciation to my supervisor,

Associate Professor Dr. Luqman Chuah Abdullah for his remarkable encouragement

and endless support during my study. His diligence and intelligence have motivated

me to excel not only in this program, but also in my future career. I am also very

grateful to Dr. Nor Azowa Ibrahim and Dr. Chantara Thevy Ratnam (MNA), my co-

supervisor, for giving so much supports and advices. Their suggestions and advices

were very valuable and constructive in my research and writing.

I would also like to thank to technical staff namely Mr. Rizal and Ms Fariz, the

technical staff at Faculty of Forestry, Mr Ismail Abd Ghani, the technical staff at

Faculty of Engineering and Mr. Wan Ali Wan Yusof and Mr. Falah, the technical

staff at MNA.

My special thanks go to my friends Jenny, Emi, Akmil, Amir, Mozen, Anis, Shida,

Juhaida and Zariff for their encouragement and help through this research work.

Last but not least, I would like thanks those who had helped me directly and

indirectly in order to improve and complete this thesis.

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I certify that a Thesis Examination Committee has met on 27 June 2011 to

conduct the final examination of Nurfatimah binti Abu Bakar on her thesis

entitled " Effects of Grafting on Kenaf Fiber Reinforced Poly Vinyl

Chloride/Ethylene Vinyl Acetate Blend Composites " 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 degree of Master of Science.

Members of the Thesis Examination Committee were as follows: Rosfarizan binti Mohamad, PhD Associate Professor Faculty of Biotechnology and Biomolecular Sciences Universiti Putra Malaysia (Chairman) Thomas Choong Shean Yaw, PhD Associate Professor Faculty of Engineering Universiti Putra Malaysia (Internal Examiner) Mohamad Amran bin Mohd Salleh, PhD Faculty of Engineering Universiti Putra Malaysia (Internal Examiner) Mat Uzir bin Wahit, PhD Associate Professor Faculty of Chemical and Resources Engineering Universiti Teknologi Malaysia (External Examiner)

NORITAH OMAR, PhD Associate Professor and Deputy Dean School of Graduate Studies Universiti Putra Malaysia Date:

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This thesis was submitted to the Senate of Universiti Putra Malaysia and has been

accepted as fulfilment of the requirment for the degree of Master of Science. The

members of the Supervisory Committee were as follows:

Luqman Chuah Abdullah, PhD

Associate Proffesor

Institute of Tropical Forestry and Forest Product

Universiti Putra Malaysia

(Chairman)

Nor Azowa Bin Ibrahim, PhD

Institute of Tropical Forestry and Forest Product

Universiti Putra Malaysia

(Member)

Chantara Thevy Ratnam, PhD

Reasearch Officer

Agency of Nuclear Malaysia

Bangi, Malaysia

(Member)

_______________________________

HASANAH MOHD GHAZALI, PhD

Professor and Dean

School of Graduates Studies

Universiti Putra Malaysia

Date:

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DECLARATION

I declare that the thesis is my original work except for quotations and citations

which have been duly acknowledged. I also declare that it has not been previously,

and is not concurrently, submitted for any other degree at Universiti Putra Malaysia

or at any other institutions.

________________________________

NURFATIMAH BINTI ABU BAKAR

Date:

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TABLES OF CONTENTS

Page

ABSTRACT iii

ABSTRAK v

ACKNOWLEDGEMENTS vii

APPROVAL viii

DECLARATION x

LIST OF TABLES xiv

LIST OF FIGURES xvi

LIST OF ABBREVIATIONS xx

CHAPTER

1 INTRODUCTION

1.1 Overview 1-1

1.2 Significant of Study 1-3

1.3 Problem Statements 1-4

1.4 Objectives of the Study 1-5

1.5 Organization of the Chapters 1-5

2 LITERATURE REVIEW

2.1 General Background 2-1

2.1.1 Polymer Blends 2-1

2.1.2 Graft Copolymerization 2-1

2.2 Poly vinyl chloride 2-2

2.3 Ethylene Vinyl Acetate 2-5

2.4 Natural Fibers for Reinforcement 2-9

2.4.1 Malaysia Scenario 2-10

2.4.2 Characterization and Properties of Kenaf 2-12

2.5 Surface Chemical Modifications of Natural Fibers 2-15

2.5.1 Graft Copolymerization 2-16

2.6 Natural Fibers Reinforced Thermoplastic Composites 2-19

2.6.1 Mechanical Properties of Natural Fiber Composites 2-22

2.6.2 Thermal Properties of Natural Fiber Composites 2-23

2.7 Optimization Using Response Surface Methodology (RSM) 2-24

3 METHODOLOGY

3.1 Materials 3-1

3.1.1 Kenaf Fiber 3-1

3.1.2 Poly vinyl chloride (PVC) 3-1

3.1.3 Ethylene Vinyl Acetate (EVA) 3-2

3.1.4 Methyl methacrylate (MMA) 3-2

3.1.5 Other Chemicals 3-2

3.2 Synthesis of Kenaf Grafted Poly (methyl methacrylate) by

Chemical Method 3-2

3.2.1 Graft Copolymerization 3-2

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3.2.2 Determination of Percentage of Grafting 3-5

3.2.3 Experimental Design and Statistical Analysis 3-5

3.2.4 Characterization of Kenaf-g-PMMA 3-7

3.3 Sample Preparation 3-8

3.4 Blend preparation of the Composites 3-8

3.5 Mechanical Test 3-9

3.5.1 Tensile Test 3-9

3.5.2 Flexural Test 3-10

3.5.3 Impact Test 3-10

3.5.4 Hardness Test 3-10

3.6 Thermal Test 3-11

3.6.1 Differential Scanning Calorimetry (DSC) 3-11

3.6.2 Thermogravimetric Analysis (TGA) 3-12

3.6.3 Dynamic Mechanical Analysis (DMA) 3-12

3.7 Surface Electron Microscopy (SEM) 3-13

4 RESULTS AND DISCUSSIONS

4.1 Optimization of Kenaf Grafted Poly Methyl Methacrylate 4-1

4.1.1 Model Fitting 4-1

4.1.2 Analysis of Variance (ANOVA) 4-1

4.1.3 Effects of Parameters 4-6

4.1.4 Optimization of Reaction 4-9

4.1.5 FTIR analysis 4-10

4.1.6 Surface Morphology 4-11

4.1.7 Summary 4-14

4.2 Mechanical Properties 4-14

4.2.1 Tensile Properties 4-14

4.2.2 Flexural Properties 4-19

5.2.3 Impact Strength 4-23

4.2.4 Hardness 4-24

4.2.5 Summary 4-25

4.3 Thermal Properties 4-26

4.3.1 Differential Scanning Calorimetry 4-26

4.3.2 Thermal Degradation and Stability 4-29

4.3.2.1 Thermal Analysis of PVC/EVA Blend,

Grafted and Ungrafted Kenaf 4-29

4.3.2.2 Thermal Analysis of Grafted and Ungrafted

Kenaf Reinforced PVC/EVA Blend 4-31

4.3.3 Dynamic Mechanical Analysis 4-35

4.3.3.1 Storage Modulus 4-35

4.3.3.2 Loss Modulus 4-38

4.3.3.3 Loss Tangent (tan) 4-40

4.3.4 Summary 4-45

5 CONCLUSIONS AND RECOMMENDATIONS

5.1 Conclusions 5-1

5.2 Suggestions for Further studies 5-3

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REFERENCES R-1

APPENDICES A-1

BIODATA OF STUDENT B-1