i EFFECT OF MOISTURE ON TENSILE PROPERTIES OF OIL PALM ...

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EFFECT OF MOISTURE ON TENSILE PROPERTIES OF OIL PALM

EMPTY FRUIT BUNCH (EFB) UNSATURATED POLYESTER

COMPOSITES

SULAIMAN BIN MOHAMAD ALI

This report is submitted to Faculty of Engineering University Malaysia Sarawak

(UNIMAS) as to fulfil the requirements of Bachelor Degree Program

Mechanical Engineering and Manufacturing Systems

Faculty of Engineering

UNIVERSITI MALAYSIA SARAWAK

2008

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Dedicated to my beloved father and mother…

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ACKOWLEDGEMENT

I would like to take this opportunity to express my gratitude to the entire

individual for their guidance, time and contribution towards the completion of my

final year project.

First of all, I would like to thank my supervisor, Puan Mahshuri Binti Yusof for

giving me the chance to be one of her student in this final year project. Her

knowledge and experience had helped and guided me a lot in performing my project.

I will never forget the effort and time she sacrificed for me in matter to finish this

project.

Secondly, I would like to express my appreciation to all the laboratory technical

staff of mechanical department especially Mr. Sabariman, Mr. Rhyier and Mr. Masri

in assisting me using the laboratory apparatus and facilities.

Last but not least, my beloved family for their blessings and support, fellow

course mate and friends for giving opinions and shared their wisdom. Thank you

very much for those involved directly or indirectly for the completion of this project.

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ABSTRAK

Gentian daripada tandan tanpa buah kelapa sawit telah diguna dalam kajian ini

sebagai gentian yang berpotensi untuk digunakan dalam menghasilkan bahan

komposit berasaskan poliester. Bahan komposit berasaskan poliester daripada

gentian dari tandan tanpa buah kelapa sawit telah dihasilkan dalam susunan lapisan

yang rambang atau berteraburan. Spesimen-spesimen ini dikelaskan berdasarkan

jumlah gentian (10%, 15% dan 20%) yang terdapat di dalam komposit, jenis rawatan

(tidak di rawat, larutan Natrium Hidroksida dan larutan Silane) dan kandungan air

(1%, 2%, 3% dan 4%). Ujian kadar resapan air dan ujian tegangan berdasarkan

piawai ASTM D3039 telah dijalankan ke atas semua spesimen untuk memahami sifat

kandungan air tehadap tegangan komposit tersebut. Keputusan ujian menujukkan

komposit yang tidak dirawat dengan 20% nisbah gentian dan 1% kandungan air

mempunyai sifat mekanikal yang paling baik dari segi kekuatan tegangan, sifat

kelenturan dan tenaga apabila putus. Malahan, keputusan ujian juga menunjukkan

apabila peningkatan tahap kandungan air dalam semua spesimen yang mempunyai

nisbah gentian dan jenis rawatan yang sama berlaku, kekuatan tegangan semakin

berkurangan.

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ABSTRACT

This research addressed to the oil palm empty fruit bunch fibre as the potential fibre

for fibre reinforced polymer composites. An oil palm empty fruit bunch reinforced

polyester composites have been fabricated in a random orientation. The specimens

are categorized according to its fibre volume fraction (10%, 15% and 20%), the type

of surface treatment (untreated, NaOH and Silane), and moisture content (1%, 2%,

3% and 4%). A moisture absorption test and tensile test according to ASTM D3039

standard has been carried out in order to determine the moisture content and

understand the moisture effects of the composite under tension. The results showed

that the untreated composites with 20% fibre volume fraction and 1% of moisture

content had the best mechanical properties in terms of tensile strength, Young’s

modulus and energy at break. Furthermore, it also verified that the increment of

moisture content in specimen with the same fibre volume fraction and surface

treatment reduced the tensile strength.

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TABLE OF CONTENTS

NO. CONTENTS PAGES

CONFIRMATION LETTER OF PROJECT REPORT

SUBMISSION

APPROVAL SHEET

TITLE PAGE i

DEDICATION ii

ACKNOWLEDGEMENT iii

ABSTRAK iv

ABSTRACT v

TABLE OF CONTENTS vi

LIST OF TABLES x

LIST OF FIGURES xi

ABBREVIATIONS xviii

1.0 CHAPTER 1: INTRODUCTION

1.1 Introduction 1

1.2 Natural Composites 3

1.3 Moisture 4

1.4 Scope and Objective 4

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2.0 CHAPTER 2: LITERATURE REVIEW

2.1 Introduction 6

2.2 Composite Materials 6

2.3 Fibres 9

2.3.1 Natural Fibres 10

2.3.2 Empty Fruit Bunch (EFB) Fibres 11

2.4 Fibre Matrix Bonding (Coupling Agent) Effects 13

2.5 Resins 15

2.5.1 Unsaturated Polyester Resins 16

2.6 Tensile Test Theory 18

2.6.1 Tensile / Elastic Properties of Random Oriented Short

Fibre Composites 22

2.7 Moisture Content Behaviour of Polymeric Composite Materials 25

3.0 CHAPTER 3: METHODOLOGY

3.1 Introduction 35

3.2 Specimen Preparation 36

3.2.1 Raw Material Sources and Handling 36

3.2.2 Empty Fruit Bunch (EFB) Fibre Extraction 37

3.2.3 Fibre Chemical Treatments 38

3.2.3.1 Silane Treatment 39

3.2.3.2 Natrium Hydroxide (NaOH) Treatment 40

3.3 Fibre Orientation 41

3.4 Fibre Volume Fraction. 42

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3.5 Specimen Fabrications. 44

3.6 Curing 46

3.7 Tabbing on Test Specimen. 47

3.8 Cutting the Specimen . 48

3.9 Total Number of Test Specimens 48

3.10 Tensile Specimen 49

3.11 Specimen Testing. 49

3.11.1 Moisture Absorption Parameters 50

3.11.2 Tensile Test Testing Method for Tensile Properties of

Polymer Matrix Composites [ASTM D3039] 51

3.11.3 Scanning Electron Microscope (SEM) Analysis 54

4.0 CHAPTER 4: RESULTS AND DISSCUSSIONS

4.1 Introduction 55

4.2 Moisture Absorption Determination 56

4.3 Result and Data of the Tensile Test 58

4.3.1 Tensile Test Results of Untreated Specimens 59

4.3.2 Tensile Test Results for Specimens Treated with NaOH 62

4.3.3 Tensile Test Results for Specimens Treated with Silane 65

4.4 Tensile Strength of Untreated and Treated EFB Reinforced

Polyester Composites 68

4.5 Stiffness of Treated and Untreated EFB Reinforced Polyester

Composites 71

4.6 Energy at Break of Treated and Untreated EFB Reinforced

Polyester Composites 74

4.7 Scanning Electron Microscope (SEM) Analysis 77

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5.0 CHAPTER 5: CONCLUSIONS AND RECOMMENDATIONS

5.1 Introduction 80

5.2 Conclusions 80

5.3 Recommendations 83

REFERENCES 85

APPENDIX 89

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LIST OF TABLES

TABLE

PAGE

Table 2.1: Fibres advantages and disadvantages 10

Table 2.2: Physical and mechanical properties of

selected natural fibres and synthetic fibres 11

Table 2.3: Comparison of Typical Ranges of Property

Values for Thermosets and Thermoplastics 16

Table 2.4: Detail of ASTM Tensile Test Method 19

Table 2.5: Several Polymer Resins Water Absorption

Property at Room Temperature 26

Table 3.1: Numbers of Test Specimens Prepared

According to the Different Coupling Agent and

Volume Fraction 49

Table 5.1: General Results of The Research 82

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LIST OF FIGURES

FIGURE PAGES

Figure 1.1: Oil Palm Empty Fruit Bunch 2

Figure 2.1: Phases of a composite material 7

Figure 2.2: Oil Palm Empty Fruit Bunch (EFB) 12

Figure 2.3: Polyester: (a) Constitution of the Resin

(b) Cured Resin with Cross-Linked Network 17

Figure 2.4: Load Applied on Tensile Test 20

Figure 2.5: Stress-Strain Curve of an Idealized

Fibre-Reinforced Composite 22

Figure 2.6: Diagram of Random Oriented Short

Fiber-Reinforced Composite 23

Figure 2.7: Effect of Moisture Absorption on The Fatigue

Behaviour of Epoxy Composites with

(a) E. Glass and (b) Kevlar 49 27

Figure 2.8: Effects of Internal Stress on The Measured

Water Uptake of A Graphite / Thermoplastic 29

Figure 2.9: Hygric Strains In Unidirectional AS4/3501-6

Carbon / Epoxy Composite as A Function Of

Moisture Concentration 34

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Figure 3.1: The process flow of the Project 35

Figure 3.2: Empty Fruit Bunch Soak in Water 37

Figure 3.3: Empty Fruit Bunch Fibres 38

Figure 3.4: EFB Fibres after the Surface Treatment

with Silane 39

Figure 3.5: EFB Fibres after the Surface Treatment

with NaOH 41

Figure 3.6: The Specimen’s Fibre Orientation with

Random Oriented Chopped Short Fibre 42

Figure 3.7: The Dimension of the Mould 45

Figure 3.8: Cold Press (a) press open – loading resin;

(b) press closed – pressure applied 46

Figure 3.9: The Specimen Water Absorption Process 50

Figure 3.10: The Specimen Weighing Process 51

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Figure 3.11: Testometric 52

Figure 3.12: The tensile test specimen according to

ASTM D3039; (a) plane view (b) side view 53

Figure 3.13: Scanning Electron Microscope (SEM) 54

Figure 4.1: Weight Gain versus Time

(10% Fibre Volume Fraction) 56





Figure 4.4: Stress-Strain Curves for Tensile Test of 10%

Fibre Volume Fraction with 1%, 2% and 3%

Moisture Content (Untreated) 59




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Figure 4.7: Tensile Strength of Untreated EFB Reinforced

Polyester Composites for 10%, 15% and 20%

Fibre Volume Fractions 61



Moisture Content (NaOH) 62







Figure 4.11: Tensile Strength of NaOH Treated EFB

Polyester Reinforced Composites for 10%,

15% and 20% Fibre Volume Fraction 64

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Moisture Content (Silane) 65







Figure 4.15: Tensile Strength of Silane Treated EFB

Reinforced Polyester Composites for 10%,

15% and 20% Fibre Volume Fraction 67

Figure 4.16: Tensile Strength of Untreated and Treated

EFB Reinforced Polyester Composites for

10% Fibre Volume Fraction 68




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Figure 4.19: Stiffness of Untreated and Treated EFB

Reinforced Polyester Composites for 10%

Fibre Volume Fraction 71







Figure 4.22: Energy at Break of Untreated and Treated EFB

Polyester Reinforced Composites for 10%





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Figure 4.25: Scanning Electron Microscope (SEM) Image

of (a) Untreated, (b) NaOH treated and

(c) Silane Treated Fibre in Dry Condition

(100µm) 79

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ABBREVIATIONS

σ Stress

ε Strain

tΕ Modulus of Elasticity in tension

fσ Stress of fibre

mσ Stress of matrix

fν Volume of fibre

mν Volume of matrix

Ltuσ Longitudinal tensile strength

c moisture concentration

D diffusion coefficient

t time

M Moisture uptake

ρ Density

W Weight

m mass

Lmin Tab Length

cσ Strength of composite

τ Shear strength

t Thickness

Wf Weight of fibres

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W m Weight of matrix

W c Weight of composites

ASTM American Society for Testing and

Materials

Sodium Hydroxide NaOH

MPa Mega Pascal

EFB Empty Fruit Bunch

°C Degree Celsius

F Force

g Gram

M Mass

mg Milligram

min Minute

ml Milliliter

mm Millimeter

Chapter 1 Introduction

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CHAPTER 1

INTRODUCTION

1.1 Background

Oil palm, Elaeis guineensis, is originated from western Africa continent,

particularly in East Nigeria, where it has been traditionally used as a source of food.

It was introduced to Malaysia in 1917 as a decorative plant but was grown

commercially since 1980’s as an agricultural crop for its versatility in application of

oil and fat. To date, palm oil constitutes about 21% and 47% of global edible oil and

fat production and market trade respectively (Basiron et al, 2004). By 2020, it is

expected to constitute 40% of the world market and to overtake soy bean as the

world largest consumed edible oil (Basiron and Weng, 2004).

The palm oil can be commercialized and manufactured to many varieties of

product. The nut can be used as foodstuffs and make into cooking oil, margarine,

cream and pastry. Besides, it can be used in industrial products such as raw materials

for cosmetics, soap, detergent and candles. The commercialization of the oil palm


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also contributes to environmental problem especially from its waste. Oil Palm Empty

Fruit Bunch (EFB) (Figure 1.1), is the leading solid waste in the palm oil mills

industry but it is also can be utilised. Due to its bulky nature, EFB causes high land-

fill disposal cost and was traditionally burnt in simple incinerators where a tonnes of

EFB produces only 4 kg of ash (Prasetsan, 1996).

Figure 1.1: Empty Fruit Bunch

However, due to the new environmental laws, some countries such as Malaysia

have banned this type of removal. Therefore, in some plantations, EFB are left to

decompose under oil palm trees but such acts result in very high breeding of Oryctes

rhinoceros beetles, which has become the most serious pest for oil palm trees and

could cause up to 92 % crop loss (Ooi et al, 2004).

This research addressed the oil palm crop waste such as EFB as a potential fibre

for particle reinforced composite. This is due mainly to the availability of the waste


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which can be massively found all over Malaysia. Moreover, the technology of

natural fiber-polymer composite had attracted a lot of interest from the industrial

sectors such as construction, aviation and automotive.

1.2 Natural Composites

According to Schaffer et. al. (1999), composites are materials formed by uniting

two or more basic materials in which one materials, called the reinforcing phase is in

form of fibres, sheets or particles, embedded in another material called the matrix.

The most common applications for fibre reinforces composites are as structural

materials where rigidity, strength, and low density are important. Examples of some

current applications of composites include the diesel piston, brake shoes and pad,

tires, and the Beechcraft aircraft in which 100% of the structural component are

composites (Schaffer et al, 1999).

Other form of composites that are very popular nowadays and easily available

from the natural resources are natural composite (natural fibres). The examples of

natural fibres are cotton, flax, jute, hemp, ramie, wood, straw, hair, wool, palm,

coconut, banana and silk. In recent years, the use of natural fibres as reinforces in the

fibre thermoplastic composites has been of great interest, particularly to automotive

industry. These fibres have many advantages such as low density, high specific


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strength and modulus, relative non-abrasiveness, ease of fibre surface modification,

wide availability and renewability (Krishnan, 1987).

1.3 Moisture

Other than having to withstand with loading extremes, composites materials

have also to survive in a range of different environment of moisture and temperature.

Most of the polymer matrix composites absorb moisture when exposed to humid air

or water environments by instantaneous surface absorption followed by diffusion

through the matrix (Mallick, 1993). This is usually limited to the resin matrix, but

some fibres also absorb moisture (Matthews and Rawlings, 1999). Moreover from

several past study, this environmental effect is believed affecting the mechanical

properties of the composites material.

1.4 Scope and Objective

The main objective of this study is to investigate the moisture effects of

untreated and treated oil palm reinforced polymer composites that was constructed

with different volume fraction and random orientation of fibres under tensile test.


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In order to achieve the primary objective, the research will be carried out

according to ASTM D3039 which is a standard test method for tensile properties of

polymer matrix composite material. The fibres are treated with Silane 174 and

Sodium Hydroxide (NaOH). The properties of untreated composite, composite

treated by silane and treated with NaOH are finally compared.

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