Faculty of Mechanical and Manufacturing Engineering Technology

Faculty of Mechanical and Manufacturing Engineering

Technology

EFFECT OF STITCHING ON KENAF WOVEN FABRIC EMBEDDED

THERMOSET BINDER SYSTEM IN INTRAPLY COMPOSITE

Michelle Lye Chuok Fang

Bachelor of Manufacturing Engineering Technology (Process and Technology)

2018

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EFFECT OF STITCHING ON KENAF WOVEN FABRIC EMBEDDED THERMOSET

BINDER SYSTEM IN INTRAPLY COMPOSITE

MICHELLE LYE CHUOK FANG

A thesis submitted

is fulfilment of the requirements for the degree of Bachelor of Manufacturing

Engineering Technology (Process and Technology)

Faculty of Mechanical and Manufacturing Engineering Technology

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

2018

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA

TAJUK: EFFECT OF STITCHING ON KENAF WOVEN FABRIC EMBEDDED THERMOSET BINDER SYSTEM IN INTRAPLY COMPOSITE

SESI PENGAJIAN: 2018/19 Semester 2 Saya MICHELLE LYE CHUOK FANG mengaku membenarkan Laporan PSM ini disimpan di Perpustakaan Universiti

Teknikal Malaysia Melaka (UTeM) dengan syarat-syarat kegunaan seperti berikut:

1. Laporan PSM adalah hak milik Universiti Teknikal Malaysia Melaka dan penulis.

2. Perpustakaan Universiti Teknikal Malaysia Melaka dibenarkan membuat salinan untuk tujuan pengajian sahaja dengan izin penulis.

3. Perpustakaan dibenarkan membuat salinan laporan PSM ini sebagai bahan pertukaran antara institusi pengajian tinggi.

4. **Sila tandakan ( )

SULIT

TERHAD

TIDAK TERHAD

(Mengandungi maklumat yang berdarjah keselamatan atau

kepentingan Malaysia sebagaimana yang termaktub dalam

AKTA RAHSIA RASMI 1972)

(Mengandungi maklumat TERHAD yang telah ditentukan

oleh organisasi/badan di mana penyelidikan dijalankan)

Alamat Tetap:

105, Jalan Nilam 3,

Taman Jayamas,

70200 Seremban, Negeri Sembilan.

Tarikh: ______________________

Disahkan oleh:

Cop Rasmi:

Tarikh: _______________________

** Jika Laporan PSM ini SULIT atau TERHAD, sila lampirkan surat daripada pihak

berkuasa/organisasi berkenaan dengan menyatakan sekali sebab dan tempoh laporan PSM ini

perlu dikelaskan sebagai SULIT atau TERHAD.

DECLARATION

I hereby, declared this report entitled “Effect of Stitching on Kenaf Woven Fabric

Embedded Thermoset Binder System in Intraply Composite” is the results of my own

research except as cited in references.

Signature : ………………………………………….

Name : MICHELLE LYE CHUOK FANG

Date : …………………………………………

APPROVAL

I hereby declare that I have read this thesis and in my opinion this thesis is sufficient in

terms of scope and quality for the award Bachelor’s degree of Bachelor of Manufacturing

Engineering Technology (Process and Technology).

Signature : ………………………………………….

Supervisor Name : IR. DR. MOHD YUHAZRI BIN YAAKOB CEngMIMechE

Date : …………………………………………

DEDICATION

Dedicated to

my beloved father, Lye Teik Khon

my appreciated mother, Chiow Wai Kam

my adored siblings, Merlyn Lye Chuok Zhin, Melanie Lye Chuok Xin and Adrian Lye Qe Bin

my teammates Duncan Ling Ruey Shan, Finiks Anak Kanis and my senior Mohd Amirhafizan

Bin Husin

my special friend Ang Siew Khim for giving me moral support, cooperation, encouragement

and also understandings.

Thank You So Much & Love You All Forever

i

ABSTRACT

Natural fibers have the high tendency to replace synthetic fibers because its offer high strength properties, eco-friendly, low cost and low density. Therefore, the development of natural fibers has been the interest to researcher and many fields of the manufacturers such as aircraft and automotive used as reinforcement to fabricate a high strength property of composite materials. Besides that, there are many researchers focused on the natural fibers-based composite in the form of laminate, but there is no specific study on the combination of stitches and natural fibers to fabricate an intraply composite. The effect of stitching on kenaf woven fabric embedded thermoset binder system in intraply concept was investigated. The purpose of this study is to develop an intraply composite by incorporating kenaf fibers as reinforcement with different stitching parameters and epoxy resin as matrix. There are eight types of stitch designs will be stitched on kenaf woven fabric by using singer 8280 electronic sewing machine. This intraply composite is fabricated by combination of hand lay-up technique and vacuum bagging technique to enhance the properties of the composite. Furthermore, all fabrications and the testing methods are based on ASTM standards. Next, the fracture surface morphology of the samples tested were analyzed by using scanning electron microscopy (SEM). In this study, the result revealed that T60/60 stitch woven kenaf produced the best mechanical performance by increased the specific strength of 53.17 % compared to unstitch woven kenaf. From the study, the performance of best stitch design has potential to produce natural helmet as to replaced synthetic thermoplastic to enhance the impact and tensile properties of the composite

ii

ABSTRAK

Serat semulajadi mempunyai kecenderungan tinggi untuk menggantikan serat sintetik kerana menawarkan sifat kekuatan tinggi, mesra alam, kos rendah dan kepadatan rendah. Oleh itu, perkembangan serat semulajadi telah menjadi kepentingan penyelidik dan banyak bidang pengilang seperti pesawat dan automotif yang digunakan sebagai pengukuhan untuk menghasilkan kekuatan tinggi bahan komposit. Di samping itu, terdapat banyak penyelidik yang menumpukan pada komposit berasaskan gentian semulajadi dalam bentuk lamina, tetapi tidak ada kajian khusus mengenai gabungan jahitan dan serat semulajadi untuk membuat komposit intraply. Oleh itu, matlamat kajian ini adalah untuk mengkaji kesan jahitan pada kain tenunan kenaf yang tertanam termoset pengikat sistem dalam konsep intraply. Tujuan kajian ini adalah untuk membangun komposit intraply dengan menggabungkan serat kenaf sebagai pengukuhan dengan parameter jahitan yang berbeza dan resin epoksi sebagai matriks. Terdapat lapan jenis reka bentuk stitch yang akan dijahit pada kain tenunan kenaf dengan menggunakan penyanyi 8280 terlebih dahulu mesin jahit elektronik. Komposit intraply ini dibuat dengan gabungan teknik pemasangan tangan dan teknik pembaut vakum untuk meningkatkan sifat komposit. Tambahan pula, semua fabrikasi dan kaedah ujian berdasarkan piawaian ASTM. Seterusnya, morfologi permukaan patah sampel yang diuji dianalisis dengan menggunakan mikroskop elektron imbasan (SEM). Dalam pengajian ini menunjukkan bahawa T60 / 60 stitch tenunan kenaf menghasilkan prestasi mekanikal yang terbaik dengan meningkatkan kekuatan spesifik sebanyak 53.17% berbanding dengan kenaf tenunan yang tidak teratur. Dari kajian ini, prestasi reka bentuk jahitan terbaik berpotensi menghasilkan topi keledar asli untuk menggantikan termoplastik sintetik untuk meningkatkan kesan dan sifat tegangan komposit

iii

ACKNOWLEDGEMENT

I would like to express my gratitude to everyone who supported me throughout this research study especially my beloved supervisor Prof. Madya Ir. Dr. Mohd Yuhazri Bin Yaakob CEng MIMechE. I am very thankful for his kindness, unwavering patience, aspiring guidance, advice and variable information helped me through the process at all the time. His easy explanations and open mind personality which enhance my knowledge and experience during my research study. Besides, I also thankful to him for his encouraging in using the proper grammar and consistent notation in my report writing, prof reading, and commenting on report writing. Next, I would like to thank to my lovely family: my parents and my brother and sisters for their supporting spiritually throughout my thesis writing. I would also like to give my special thanks to my best friend Ang Siew Khim who gave me much of motivation and mentally supports. Thanks for sharing information and moral support to improve my work. Lastly, I would like to thank to my teammates Duncan Ling Ruey Shan, Finiks Anak Kanis and my senior Mohd Amirhafizan Bin Husin who always contribute me their critical suggestions, cooperation and comments throughout my research. Thanks for the great friendship.

iv

TABLE OF CONTENTS

DECLARATION PAGE

APPROVAL DEDICATION ABSTRACT i

ABSTRAK ii

ACKNOWLEDGEMENTS iii

TABLE OF CONTENTS iv

LIST OF TABLES vii

LIST OF FIGURES ix

LIST OF ABBREVIATIONS xv

LIST OF SYMBOLS xvi

CHAPTER 1. INTRODUCTION 1

1.1 Background 1 1.2 Problem Statement 4 1.3 Objectives 6 1.4 Scope 6 1.5 Rationale of Research 7 1.6 Summary of Methodology 7 1.7 Thesis Organization 9

2. LITERATURE REVIEW 10

2.1 Introduction to Composite 10 2.1.1 Intraply composite 11 2.1.2 Synthetic intraply 12 2.2 Kenaf 13 2.2.1 Kenaf fiber composite 15 2.2.2 Thermoset/matrix in kenaf composite 17 2.2.3 Application of kenaf composite in automotive industry 19 2.3 Binder System and Fabrication Process 21 2.4 Stitching 25 2.4.1 Type of stitching 27 2.4.2 Structure 29 2.4.3 Process of stitching 31 2.5 Woven Fabric 32 2.5.1 Type of woven 33 2.6 Testing 35 2.6.1 Testing on intraply composite 37 2.7 Summary/Research Gap 38 3. METHODOLOGY 40

3.1 An Overview of Methodology 40 3.2 Raw Material Preparation 42 3.2.1 Kenaf 42 3.2.2 Woven kenaf roving 43

3.2.3 Epoxy and hardener 45

v

3.3 Stitching Design on Woven Kenaf Fabric 46 3.4 Stitching Process 47 3.5 Intraply Composite Preparation 48 3.6 Mechanical Testing 49 3.6.1 Tensile testing 50 3.6.2 Impact testing 51 3.6.3 Hemisphere pressure clamped test (3D stamping test) 52 3.7 Scanning Electron Microscope 53

4. RESULTS AND DISCUSSIONS 55

4.1 Overview 55 4.2 Properties of Original Woven Kenaf Fiber 57 4.2.1 Tensile performance of O unstitch 58 4.2.2 Impact performance of O unstitch 61

4.2.3 4.2.3 Hemisphere clamped test analysis of O unstitch 63 4.3 Properties of Vertical Stitch on Woven Kenaf Fiber 65 4.3.1 Tensile performance of V stitch 66 4.3.2 Impact performance of V stitch 69

4.3.3 Hemisphere clamped test analysis of V stitch 71 4.4 Properties of Tilt 60° Stitch on Woven Kenaf 72 4.4.1 Tensile performance of T60 stitch 74 4.4.2 Impact performance of T60 stitch 77

4.4.3 Hemisphere clamped test analysis of T60 stitch 79 4.5 Properties of Tilt 30° Stitch on Woven Kenaf 80

4.5.1 Tensile performance of T30 stitch 82 4.5.2 Impact performance of T30 stitch 85 4.5.3 Hemisphere clamped test analysis of T30 stitch 86 4.6 Properties of Horizontal Stitch on Woven Kenaf Fiber 88 4.6.1 Tensile performance of H stitch 90 4.6.2 Impact performance of H stitch 92 4.6.3 Hemisphere clamped test analysis of H stitch 94 4.7 Properties of Box Stitch on Woven Kenaf Fiber 95 4.7.1 Tensile performance of Box stitch 97 4.7.2 Impact performance of Box stitch 99 4.7.3 Hemisphere clamped test analysis of Box stitch 101

4.8 Properties of Tilt 30°/Tilt 30° Stitch on Woven Kenaf Fiber 103 4.8.1 Tensile performance of T30/30 stitch 104 4.8.2 Impact performance of T30/30 stitch 107 4.8.3 Hemisphere clamped test analysis of T30/T30 stitch 108 4.9 Properties of Tilt 45°/Tilt 90° Stitch on Woven Kenaf Fiber 110 4.9.1 Tensile performance of T45/90 stitch 111 4.9.2 Impact performance of T45/90 stitch 113 4.9.3 Hemisphere clamped test analysis of T45/90 stitch 115 4.10 Properties of Tilt 60°/Tilt 60° Stitch on Woven Kenaf Fiber 116 4.10.1 Tensile performance of T60/60 stitch 118 4.10.2 Impact performance of T60/60 stitch 120 4.10.3 Hemisphere clamped test analysis of T60/60 stitch 122 4.11 Comparison Effect of Tensile Strength in Different Stitching Design

123

vi

4.12 Comparison Effect of Impact Strength in Different Stitching Design

129

4.13 Comparison Effect of Hemisphere Test in Different Stitching Design

132

4.14 Application of The Best Stitching Design 136 4.14.1 Mechanical performance of natural helmet 137 4.14.2 Fracture analysis of both helmets 139 4.15 Summary of Analysis Finding 140

5. CONCLUSIONS AND RECOMMENDATIONS FOR FUTURE

RESEARCH

143

5.1 Conclusions 143 5.2 Recommendations 146 5.3 Sustainability Element 147 5.4 Commercial Value and Potential 148

REFERENCES 150

APPENDICES 162

Gantt Chart PSM I 162 Gantt Chart PSM II 164

vii

LIST OF TABLES

TABLE TITLE PAGE

2.1 Comparison of mechanical properties of various polymers 18

2.2 Fabrication technique used in composite by various research 24

2.3 Summary of previous researches finding 39

3.1 Summary of kenaf fiber properties 42

3.2 Specific data 46

3.3 Specification of cotton fiber 48

3.4 Testing standard for mechanical testing 50

4.1 Summary type of stitching design 56

4.2 9 types of stitch woven kenaf 56

4.3 Average properties of unstitch woven kenaf 58

4.4 The properties of hemispheric performance of unstitch woven kenaf 64

4.5 Average properties of V stitch woven kenaf 66

4.6 The properties of hemispheric performance of V stitch woven kenaf 71

4.7 Average properties of T60 stitch woven kenaf 74

4.8 The properties of hemispheric performance of T60 stitch woven

kenaf

80

4.9 Average properties of T30 stitch woven kenaf 81

4.10 The properties of T30 stitch woven kenaf 87

4.11 Average properties of H stitch woven kenaf 89

4.12 The properties of hemispheric performance of H stitch woven kenaf 94

4.13 Average properties of Box stitch woven kenaf 96

viii

4.14 The properties of hemispheric performance of Box stitch woven

kenaf

102

4.15 Average properties of T30/30 stitch woven kenaf 104

4.16 The properties of hemispheric performance of T30/30 stitch woven

kenaf

109


4.18 The properties of hemispheric performance of T45/90 woven kenaf 115


4.20 The properties of hemispheric performance of T60/60 stitch woven

kenaf

122

4.21 Summary tensile strength for all type of stitching design 124

4.22 Summary specific strength for all type of stitching design 125

4.23 Summary of impact toughness and energy absorption for all stitching

designs

130

4.24 Summary hemisphere performance for all type of stitching design 133

4.25 Overview deformation of all types stitching woven kenaf 135

4.26 Summary of both helmets properties 139

ix

LIST OF FIGURES

FIGURE TITLE PAGE

1.1 Flow chart of the overall methodology 8

2.1 The concept of composite system 11

2.2 Microscale fiber bundle to nanoscale cellulose microfibril in kenaf

stem

14

2.3 SEM micrographs of the (a) untreated kenaf fiber and (b) treated

kenaf fiber with 6 % of sodium hydroxide

16

2.4 Micrographs on the cross-section of (a) untreated and (b) treated

kenaf fiber with reinforcement of epoxy

16

2.5 Door trim base material utilized by 60 % of natural fiber 20

2.6 Kenaf battery tray used by Ford of Europe 21

2.7 Compression molding process to fabricate polymer composite 22

2.8 Hand lay-up process 22

2.9 Cycle of resin transfer molding process 23

2.10 Schematic vacuum bagging process 24

2.11 The stitches with polyethylene-co-methacryline acid in the carbon

fiber epoxy composite

26

2.12 The effect of stitch density on tensile strength (a) and modulus (b) 27

2.13 Type of stitching pattern 28

2.14 The puncture load in different type of stitching 28

2.15 The surface structure of the non-crimp fiber with chain stitched 29

2.16 Structure of stitch density in multiple-layer woven fabric 30

x

2.17 (a) Modified lock stitch and (b) parallel or perpendicular stitch on

woven fiber composite

31

2.18 Modified chain stitching on plain laminate CFRP 32

2.19 Different weave type of woven fabric, (a) plain, (b) basket, (c)

herringbone, and (d) intraply

34

2.20 Load deflection curve of the sandwich laminates composite 36

2.21 Drop weight impact tester machine (a) and the composite: impactor

(b) and support fixture (c)

37

3.1 Flow chart of methodology 41

3.2 Kenaf fiber 43

3.3 Plain weave design kenaf 43

3.4 Fabrication of loom frame 44

3.5 Dimension of loom frame 44

3.6 Weaving process by manually hand-layup 45

3.7 Epoxy resin 46

3.8 Types of stitching design (a) Vertical-V, (b) Horizontal-H, (c) Tilt30°-T30,

(d) Tilt60°-T60, (e) Box-Box, (f) Tilt 45°/90°-T45/90, (g) Tilt 30°/30°-

T30/30, (h) Tilt 60°/60°-T60/60.

47

3.9 Singer 8280 electronic sewing machine 48

3.10 Schematic diagram of vacuum bagging 49

3.11 Instron 50 kN universal testing machine 50

3.12 The dimension of tensile testing machine (ASTM D3039) 51

3.13 Impact testing machine 52

3.14 Geometry of specimen 52

3.15 Hemispheric test for woven fabric 53

3.16 Scanning electron microscope (SEM) 54

4.1 Plain weave woven kenaf fiber 57

xi

4.2 Plain weave woven kenaf fiber after embedded with epoxy resin 56

4.3 Tensile strength and young’s modulus of unstitch woven kenaf 59

4.4 Failure mode of unstitch woven kenaf after tensile test 60

4.5 Micrograph of unstitch woven kenaf reinforced epoxy composite in

(a) 500x (b) 150x

61

4.6 Impact toughness and energy absorption of unstitch woven kenaf 62

4.7 Failure mode of unstitch woven kenaf 63

4.8 The deformed of unstitch woven kenaf. (a) Overview (b) Close up 64

4.9 V stitch on woven kenaf fiber 65

4.10 V stitch on woven kenaf fiber after embedded with epoxy resin 66

4.11 Tensile strength and young’s modulus of V stitch woven kenaf 67

4.12 Failure mode of V stitch woven kenaf after tensile test 68

4.13 Micrograph of V stitch woven kenaf reinforced epoxy composite 69

4.14 Impact toughness and energy absorption of V stitch 70

4.15 Failure mode of V stitch woven kenaf after impact test 71

4.16 The deformed of V stitch woven kenaf. (a) Overview (b) Close up 72

4.17 T60 stitch on woven kenaf 73

4.18 T60 stitch on woven kenaf fiber after embedded with epoxy resin 74

4.19 Tensile strength and young’s modulus of T60 stitch woven kenaf 75

4.20 Failure mode of T60 stitch woven kenaf after tensile test 75

4.21 Micrograph of T60 stitch woven kenaf reinforced epoxy composite 77

4.22 Impact toughness and energy absorption of T60 stitch woven kenaf 78

4.23 Failure mode of T60 stitch woven kenaf after impact test 78

4.24 The deformed of T60 stitch woven kenaf. (a) Overview (b) Close up 80

4.25 T30 stitch on woven kenaf fiber 81

xii

4.26 Shape of woven kenaf fiber 81

4.27 Tensile strength and young’s modulus of T30 stitch woven kenaf 83

4.28 Failure mode of T30 stitch woven kenaf after tensile testing 83

4.29 Micrograph of T30 stitch woven kenaf reinforced epoxy composite 84

4.30 Impact toughness and energy absorption of T30 stitch woven kenaf 85

4.31 Failure mode of T30 stitch woven kenaf after impact test 86


4.33 H stitch on woven kenaf 88

4.34 H stitch on woven kenaf fiber after embedded with epoxy resin 89

4.35 Tensile strength and young’s modulus of H stitch woven kenaf 90

4.36 Failure mode of H stitch woven kenaf after tensile testing 90

4.37 Micrograph of H stitch woven kenaf reinforced epoxy composite 91

4.38 Impact toughness and energy absorption of H stitch woven kenaf 92

4.39 Failure mode of H stitch woven kenaf after impact test 93


4.41 Box stitch on woven kenaf 96

4.42 Box stitch on woven kenaf fiber after embedded with epoxy resin 96

4.43 Tensile strength and young’s modulus of Box stitch woven kenaf 98

4.44 Failure mode of Box stitch woven kenaf after tensile testing 98

4.45 Micrograph of Box stitch woven kenaf reinforced epoxy composite 99

4.46 Impact toughness and energy absorption of Box stitch woven kenaf 100

4.47 Failure mode of Box stitch woven kenaf after impact test 101


4.49 T30/30 stitch on woven kenaf 103

4.50 T30/30 stitch on woven kenaf fiber after embedded with epoxy resin 104

xiii

4.51 Tensile strength and young’s modulus of T30/30 stitch woven kenaf 105

4.52 Failure mode of T30/30 stitch woven kenaf after tensile testing 106

4.53 Micrograph of T30/30 stitch woven kenaf reinforced epoxy

composite

106

4.54 Impact toughness and energy absorption of T30/30 stitch woven

kenaf

107

4.55 Failure mode of T30/30 stitch woven kenaf after impact test 108

4.56 The deformed of T30/30 stitch woven kenaf. (a) Overview (b) Close

up

109






composite

113


kenaf

114


4.64 The deformed of T45/90 stitch woven kenaf. (a) Overview (b) Close

up

116





xiv


composite

120


kenaf

121



4.73 Average tensile strength of all stitching design of woven kenaf 127

4.74 Specific strength of all stitching designs of woven kenaf 128

4.75 Impact toughness and energy absorption of all stitching designs of

woven kenaf

131

4.76 Maximum load of all stitching designs of woven kenaf 134

4.77 (a) Outer shell of T60/60 woven kenaf helmet (b) Inner shell of

protective padding

136

4.78 Comparison of total energy absorbed of both full prototype products 137

4.79 Comparison of energy absorbed & impact toughness for both helmets 138

4.80 (a) Surface fracture of kenaf helmet (b) Surface fracture of actual

helmet 140

4.81 Specific strength of (a) single stitch designs (b) double stitch designs 141

4.83 Hemisphere performance of (a) single stitch designs (b) double stitch

designs 142

xv

LIST OF ABBREVIATIONS

ASTM - American Society for Testing and Material

CFRP - Carbon fiber reinforced polymer

FRP - Fiber reinforced polymer

RTM - Resin Transfer Molding

SEM - Scanning electron microscope

xvi

LIST OF SYMBOLS

cm - Centimeter

m - Mass

mm - Millimeter

𝑚2 - Meter square

MPa - Mega Pascal

GPa - Giga Pascal

wt % - Weight Percentage

°C - Degree Celsius

kN - Kilo Newton

kg - Kilograms

Pa - Pascal

g - gram

v - Volume

m𝑠−1 - Meter per second

Hz - Hertz

N/𝑚𝑚2 - Newton per millimeter square

J - Joule

J/𝑐𝑚2 - Joule per centimeter square

1

CHAPTER 1

INTRODUCTION

1.1 Background

Nowadays, natural fiber composites (NFCs) are humongous used in many

applications, interest area of scientific research and product development due to it exhibition

with combined behavior of low density, stiff and strong fibrous reinforcement. In additional,

natural fiber reinforced composites also give the benefits such as environmental friendly,

corrosive resistance, chemical resistance, high mechanical performance and thermal

properties. These natural fibers included sisal, pineapple, jute, banana, oil palm, kenaf and

coir fibers (Geethamma et al., 1998). Polymer is categorized into three classes which are

elastomer, thermoplastic, and thermosetting. Besides, these polymers used as matrix to bind

together with natural fiber into form natural fiber reinforced composite. The tensile

properties of the natural fiber reinforced polymer will be affected by the interfacial adhesion

between fiber and matrix. Therefore, better interaction between the matrix and fiber must be

takes in the consideration to produce reinforced composite (Ku et al., 2011). According to

Salman et al. (2015) epoxy resin had the higher performance application compared to other

thermoset resin. Hence, the epoxy resin is selected for further explored in this research.

According to Akil et al. (2015), kenaf fiber is one of the type of natural fiber which

brings many advantages and it has high potential as a reinforcement in composite material

fields. Because each component of it plant is usable such as stalks, leaves, and seeds.

Moreover, it can easily to be harvested in one year. Kenaf fiber-reinforcement has become

common natural fiber used in various application such as automotive, construction, electrical,

2

marine, aircraft, and transportation. Kamal (2014) also agreed with this statement because

kenaf is a fast-growing property which it able to produce large volume of raw material within

a short period. It has become high demand for many industrial due to it has high

environmental sustainable which able to reduce the use of fossil fuels, low density, cost

effective, and great performance in term of physical and mechanical. Therefore, kenaf fiber

is chosen as reinforcement for this research instead of other natural fiber.

Epoxy resin is one of the family member of thermosetting. It has better properties

than other resin as it can provide low shrinkage, high adhesive strength and chemical

resistance. It has high service temperature which is up to 175 °C and most of the epoxies are

less affected by water and heat. The moisture absorption must be takes in the consideration.

This is because it will detrimental effect the mechanical properties of the composite material.

When epoxy resin serviced at high temperature, the water gain will be lowered. This can be

explained it behaviors more brittle with low elongation, low toughness, and weak resistance

to crack. Mainly application used in the aircraft industries such as adhesive for aircraft honey

comb structure, airframe and missile applications (Barbero, 2010).

Stitching is a process to bind two components together by using thread and needle.

In the modern technology, it can be performed advanced from sewing machine. Lock stitch,

modified lock stitch and chain stitch are the common stitching types used by many

researchers on the composite material. The use of stitching in the composite is to join the

composite structure to improve through-thickness strength and interlaminar fracture

toughness and impact damage tolerance (Mouritz et al., 1997). According to Pingkarawat

and Mouritz (2015), stitching will cause fiber breakage in the composite. They highlighted

that stitching on mendable composite reduced mechanical properties due to the increasing of

areal density or the size of stitched. Furthermore, the stitch density and stitch size will

influence the performance of the composite. Suhaimi et al. (2018) also agreed with this

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Faculty of Mechanical and Manufacturing Engineering Technology