i EFFECT OF MOISTURE ON TENSILE PROPERTIES OF OIL PALM ...
Transcript of 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 4.2: Weight Gain versus Time
(15% Fibre Volume Fraction) 57
Figure 4.3: Weight Gain versus Time
(20% Fibre Volume Fraction) 58
Figure 4.4: Stress-Strain Curves for Tensile Test of 10%
Fibre Volume Fraction with 1%, 2% and 3%
Moisture Content (Untreated) 59
Figure 4.5: Stress-Strain Curves for Tensile Test of 15%
Fibre Volume Fraction with 1%, 2% and 4%
Moisture Content (Untreated) 60
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Figure 4.6: Stress-Strain Curves for Tensile Test of 20%
Fibre Volume Fraction with 1%, 2% and 4%
Moisture Content (Untreated) 61
Figure 4.7: Tensile Strength of Untreated EFB Reinforced
Polyester Composites for 10%, 15% and 20%
Fibre Volume Fractions 61
Figure 4.8: Stress-Strain Curves for Tensile Test of 10%
Fibre Volume Fraction with 1%, 2% and 3%
Moisture Content (NaOH) 62
Figure 4.9: Stress-Strain Curves for Tensile Test of 15%
Fibre Volume Fraction with 1%, 2% and 4%
Moisture Content (NaOH) 63
Figure 4.10: Stress-Strain Curves for Tensile Test of 20%
Fibre Volume Fraction with 1%, 2% and 4%
Moisture Content (NaOH) 64
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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Figure 4.12: Stress-Strain Curves for Tensile Test of 10%
Fibre Volume Fraction with 1%, 2% and 3%
Moisture Content (Silane) 65
Figure 4.13: Stress-Strain Curves for Tensile Test of 15%
Fibre Volume Fraction with 1%, 2% and 4%
Moisture Content (Silane) 66
Figure 4.14: Stress-Strain Curves for Tensile Test of 20%
Fibre Volume Fraction with 1%, 2% and 4%
Moisture Content (Silane) 67
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
Figure 4.17: Tensile Strength of Untreated and Treated
EFB Reinforced Polyester Composites for
15% Fibre Volume Fraction 69
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Figure 4.18: Tensile Strength of Untreated and Treated
EFB Reinforced Polyester Composites for
15% Fibre Volume Fraction 70
Figure 4.19: Stiffness of Untreated and Treated EFB
Reinforced Polyester Composites for 10%
Fibre Volume Fraction 71
Figure 4.20: Stiffness of Untreated and Treated EFB
Reinforced Polyester Composites for 15%
Fibre Volume Fraction 72
Figure 4.21: Stiffness of Untreated and Treated EFB
Reinforced Polyester Composites for 20%
Fibre Volume Fraction 73
Figure 4.22: Energy at Break of Untreated and Treated EFB
Polyester Reinforced Composites for 10%
Fibre Volume Fraction 75
Figure 4.23: Energy at Break of Untreated and Treated EFB
Polyester Reinforced Composites for 15%
Fibre Volume Fraction 76
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Figure 4.24: Energy at Break of Untreated and Treated EFB
Polyester Reinforced Composites for 20%
Fibre Volume Fraction 77
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
Chapter 1 Introduction
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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
Chapter 1 Introduction
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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
Chapter 1 Introduction
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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.
Chapter 1 Introduction
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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.