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UNIVERSITI PUTRA MALAYSIA
PREPARATION AND PHYSICO-CHEMICAL PROPERTIES OF POLYPROPYLENE AND OIL PALM EMPTY FRUIT BUNCH FIBRE
COMPOSITES
NORAZLINA BINTI HASHIM
FS 2008 26
PREPARATION AND PHYSICO-CHEMICAL PROPERTIES OF POLYPROPYLENE AND OIL PALM EMPTY FRUIT BUNCH FIBRE
COMPOSITES
NORAZLINA BINTI HASHIM
MASTER OF SCIENCE UNIVERSITI PUTRA MALAYSIA
2008
PREPARATION AND PHYSICO-CHEMICAL PROPERTIES OF POLYPROPYLENE AND OIL PALM EMPTY FRUIT BUNCH FIBRE
COMPOSITES
By
NORAZLINA BINTI HASHIM
Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia in Fulfilment of the Requirement for the Degree of Master of Science
January 2008
Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfilment of the requirement for the degree of Master of Science
PREPARATION AND PHYSICO-CHEMICAL PROPERTIES OF
POLYPROPYLENE AND OIL PALM EMPTY FRUIT BUNCH FIBRE COMPOSITES
By
NORAZLINA BINTI HASHIM
JANUARY 2008
Chairman : Associate Professor Dr. Mohamad Zaki bin Ab Rahman, PhD Faculty : Science
Composites of polypropylene (PP) and oil palm empty fruit bunch (OPEFB) were
prepared by melt blending, and the effects of ethylene-butene copolymer (EBNR) as
an impact modifier, on the mechanical and thermal properties of OPEFB:PP
composites were investigated by using FTIR, DSC, TGA and SEM. Composites
were prepared at 10, 20, 30, 40, 50 and 60% by weight of fibre. Different fibre
loading, temperatures, rotation time and rotation speeds were tested to determine the
optimum condition of blending. Two range sizes of fibre were used in this study and
there are below 200 µm and between 200-315 µm of length (known as 200 µm and
315 µm). The study was mainly conducted on composite with 20% and 40% fibre
loading. The optimum temperature and reaction period for blending OPEFB with PP
were 170oC and 10 minutes with rotation speed at 50 rpm, respectively.
ii
The result from FTIR analysis indicated that the interaction is only physical between
the components of the composite. Tensile tests on the composites showed that EBNR
had a positive effect on the elongation at break and negative effect on tensile
modulus, but no improvement on tensile strength. This impact modifier was found to
decrease the stiffness of the composites. The impact strength was improved in
addition of EBNR, but for flexural test, no significant effect was observed. The
increasing in impact strength was shown for both notched and unnotched samples
starting from 1% of EBNR loading but they reduced when it reached at optimum
volume. Smaller fibre size, 200 µm gave higher impact strength compared to 315
µm.
The presence of EBNR on the composite made a weak improvement in thermal
stability as shown by thermogravimetric analysis (TGA). DMA studies established
that the EBNR led to reduction of stiffness and enhancing mobility of the resulting
composite. The surface morphology showed less void in EBNR composites where
OPEFB fibre seems to be covered with a smooth layer of EBNR.
The environmental degradation behaviour on the physical and mechanical properties
of OPEFB:PP composites has been studied with special reference to the influence of
ageing conditions like treatment with water, soil degradation, and chemical
resistance. With the increased of fibre loading, the water absorption was also
increased, and the addition of EBNR led to less water absorption, and the lowest
absorption was observed for 8% EBNR loading. Tensile properties decrease with
water uptake and time of immersion. The effect of alkaline (0.5M NaOH) and acidic
(0.5M HCl) solutions on the composites were investigated in a period of one month.
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The results showed the decreasing in tensile strength and mass. Temperature
dependence studies were also conducted at different temperature, 25oC, 45oC and
75oC, and found that the degradation was faster at higher temperature. The
biodegradability of composites was evaluated by the soil-burial test in six months.
The mass of composites slowly showed the decreasing after that time as expected.
iv
Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai
memenuhi keperluan untuk ijazah Master Sains
PENYEDIAAN DAN CIRI-CIRI FIZIK-KIMIA KOMPOSIT
POLIPROPILENA DAN FIBER TANDAN KOSONG BUAH KELAPA SAWIT
Oleh
NORAZLINA BINTI HASHIM
JANUARI 2008 Pengerusi : Profesor Madya Dr. Mohamad Zaki bin Ab Rahman, PhD Fakulti : Sains
Komposit polipropilena (PP) dan tandan kosong buah kelapa sawit (OPEFB) telah
disediakan melalui kaedah adunan dan kesan menggunakan pengubah impak,
kopolimer etilena-butilena (EBNR) kepada sifat mekanik dan terma komposit
OPEFB:PP telah dikaji dengan menggunakan pelbagai teknik seperti FTIR, DSC,
TGA dan SEM. Komposit disediakan pada 10, 20, 30, 40, 50 dan 60% berdasarkan
berat fiber. Amaun fiber, suhu, jangka masa dan laju putaran yang berbeza telah
dikaji untuk mendapatkan keadaan adunan yang optimum. Dua skala saiz fiber
digunakan iaitu lebih kecil daripada 200 μm dan antara 200-315 μm panjang
(dikenali sebagai 200 μm dan 315 μm). Akhirnya, penambahan OPEFB sebanyak
20% dan 40% digunakan dalam kajian ini. Suhu optimum dan jangka masa untuk
adunan OPEFB dan PP adalah 170oC, 10 minit adunan dengan 50 rpm kelajuan
putaran.
v
Analisis FTIR menunjukkan hanya terdapat interaksi fizikal antara komponen dalam
komposit. Ujian tensil bagi komposit menunjukkan EBNR memberi kesan positif ke
atas pemanjangan pada takat putus dan merendahkan modulus tensil tetapi tiada
perubahan dalam kekuatan tensil dapat dilihat. Pengubah impak ini telah
merendahkan kesan kekakuan komposit. Kekuatan impak ditingkatkan dengan
penambahan EBNR di dalam komposit, tetapi tiada perubahan lenturan dikesan.
Peningkatan dalam kekuatan impak dapat dilihat untuk kedua-dua sampel yg ditakuk
dan tak ditakuk bermula daripada 1% EBNR tetapi berkurang setelah penambahan
EBNR mencapai tahap optimum. Saiz fiber yang lebih kecil, 200 μm memberi
kekuatan impak yang lebih tinggi berbanding saiz 315 μm.
Kehadiran EBNR dalam komposit tidak memperbaiki kestabilan terma seperti yang
ditunjukkan dalam analisis termogravimetri (TGA). Kajian DMA menunjukkan
EBNR menjurus kepada penurunan kekerasan dan menambahkan mobiliti komposit.
Kajian permukaan sampel menunjukkan kurang ruang kosong terbentuk di dalam
komposit EBNR di mana OPEFB diselaputi lapisan licin EBNR.
Kesan degradasi persekitaran kepada ciri-ciri fizikal dan mekanikal bagi komposit
OPEFB:PP dikaji dengan melibatkan ujian sampel ke atas penyerapan air, degradasi
tanah dan ketahanan ke atas bahan kimia. Penyerapan air meningkat dengan
pertambahan fiber dan penambahan EBNR membawa kepada pengurangan kadar
penyerapan air dengan serapan terendah pada 8% kandungan EBNR. Ciri-ciri
kekuatan tensil berkurang dengan peningkatan penyerapan air dan waktu rendaman
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sampel. Kesan larutan alkali (0.5M NaOH) dan asid (0.5M HCl) ke atas komposit
dikaji selama satu bulan.
Keputusan menunjukkan pengurangan jisim dan kekuatan tensil. Kesan suhu ke atas
sampel dilakukan pada tiga keadaan suhu yang berbeza iaitu pada 25oC, 45oC and
75oC dan ia menunjukkan kadar degradasi bertambah dengan peningkatan suhu.
Proses biodegradasi komposit telah ditentukan dengan menanam sampel di dalam
tanah selama enam bulan. Jisim komposit telah berkurang secara perlahan-lahan
seperti yang dianggarkan.
vii
ACKNOWLEDGEMENTS
First of all, I would like to express my sincere and deepest appreciation to my
supervisor, Assoc. Professor Dr. Mohamad Zaki Ab Rahman, also co-supervisors Dr.
Nor Azowa Ibrahim and Professor Wan Md Zin Wan Yunus for their supervision,
invaluable guidance, unfailing help and superb tolerance throughout the course of
this work.
Special thanks to all the laboratory assistants in Department of Chemistry for their
help and advice.
I am also very grateful to Mr. Shahril, Mr Lim Chee Siong, Mrs. Zaidina, Mrs. Wan
Yusmawati, other lab mates and my housemates, whose help, suggestions,
encouragement and companion are of great help in sustaining the morale and
enthusiasm.
Last but not least, I would like to express my deepest gratitude to my beloved family
and Mr. Mohd Zailani Ismail whose have always believes in me, and endured with
me during difficult times. Without their unconditional and endless love, it would not
have been possible for me to complete this Master of Science thesis.
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This thesis was submitted to the Senate of Universiti Putra Malaysia and has been accepted as fulfilment of the requirement for the degree of Master of Science. The members of Supervisory Committee were as follows: Mohamad Zaki Ab Rahman, PhD Associate Professor Faculty of Science Universiti Putra Malaysia (Chairman) Wan Md Zin Wan Yunus, PhD Professor Faculty of Science Universiti Putra Malaysia (Member) Nor Azowa Ibrahim, PhD Lecturer Faculty of Science Universiti Putra Malaysia (Member)
AINI IDERIS, PhD Professor and Dean
School of Graduate Studies Universiti Putra Malaysia
Date: 10 April 2008
x
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.
___________________________
NORAZLINA BINTI HASHIM Date: 29 February 2008
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TABLE OF CONTENTS
Page
ABSTRACT іі ABSTRAK v ACKNOWLEDGEMENTS vіii APPROVAL ix DECLARATION xi LIST OF TABLES xv LIST OF FIGURES xvi LIST OF ABBREVIATION/ NOTATION/GLOSSARY OF TERMS xix CHAPTER 1 INTRODUCTION 1.1 Background of Study 1 1.1.1 Toughening of PP matrix 3 1.1.2 Toughening of Filled Polymers 3 1.1.3 Size and Dispersion of Filler 4 1.2 General Background 5 1.2.1 The Fibres-Oil Palm Production 5 1.2.2 Oil Palm Waste Products 7 1.2.3 Utilisation 7 1.2.4 Properties of Oil Palm Empty Fruit Bunch Fibres 9 1.2.5 The Matrix – Thermoplastic 11 1.2.6 Properties of Thermoplastic 13 1.2.7 Thermoplastic Impact Copolymer 14 1.2.8 Mechanical Properties of Fibre – Thermoplastic Composites 14 1.3 Objectives 16 2 LITERATURE REVIEW 2.1 Overview of Natural Fibre Composites 17 2.2 Application of Composites 18 2.3 Improvement of Fibre – Thermoplastic Reaction 20 2.3.1 Coupling/Compatibilizing Agents 22 2.3.2 Elastomer as Impact Modifier 24 2.4 Factors Affecting the Mechanical Properties of 26 Fibre – Thermoplastic Composites 2.4.1 Effect of Fibre Loading 26 2.4.2 Effect of Fibre Size 27 2.4.3 Effect of Coupling/Compatibilizing Agents 28 2.5 Ageing Condition 30 2.5.1 Water Sorption 31 2.5.2 Chemical Resistance 33 2.5.3 Biodegradation 34 2.6 Thermal and Dynamic Mechanical Properties 35
xii
3 MATERIALS AND METHODS 3.1 Introduction 37 3.2 Materials 38 3.2.1 Oil Palm Empty Fruit Bunch (OPEFB) 38 3.2.2 Thermoplastic 38 3.2.3 Ethylene-Butene Copolymer 39 3.2.4 Chemicals 40 3.3 Methods 41 3.3.1 Preliminary Test 41 3.3.1.1 Effect of Fibre Loading and Fibre Size 41 3.3.1.2 Effect of Time, Temperature and Rotation 42 Speed of Blending 3.3.2 Effect of Ethylene-Butene Copolymer (EBNR) 43 3.4 Properties Assesment 43 3.4.1 Preparation of Test Specimens 43 3.4.2 Sample for Testing 44 3.4.3 Mechanical Properties 44 3.4.3.1 Tensile Properties 44 3.4.3.2 Flexural Properties 45 3.4.3.3 Izod Impact Resistance 46 3.4.4 Ageing Test 47 3.4.4.1 Water Sorption Test 47 3.4.4.2 Chemical Resistance Test 48 3.4.4.3 Biodegradability Test 48 3.5 Characterization of the Composites 49 3.5.1 Fourier Transform Infrared (FTIR) 49 3.5.2 Thermogravimetric Analysis (TGA) 49 3.5.3 Differential Scanning Calorimetry (DSC) 50 3.5.4 Dynamic Mechanical Analysis (DMA) 51 3.5.5 Scanning Electron Microscopy (SEM) 51
4 RESULT AND DISCUSSION 4.1 Preparation of OPEFB:PP Composites 52 4.2 Fourier Transform Infra Red (FTIR) 52 4.3 Tensile Properties of Composites 55 4.3.1 Effect of Fibre Loading on Tensile Strength 55 4.3.2 Effect of Fibre Loading on Tensile Modulus 57 4.3.3 Effect of Fibre Loading on Elongation at Break 58 4.3.4 Effect of Rotation Time on Tensile Strength 60 4.3.5 Effect of Rotor Speed on Tensile Strength 61 4.3.6 Effect of Temperature on Tensile Strength 62 4.3.7 Effect of EBNR on Tensile Properties 63 4.4 Flexural Properties of Composites 65 4.4.1 Effect of Fibre Loading on Flexural Properties 65 4.4.2 Effect of EBNR on Flexural Properties 68 4.5 Impact Properties of Composites 69 4.5.1 Effect of Fibre Loading on Impact Strength 69 4.5.2 Effect of EBNR on Impact Strength 73 4.6 Thermogravimetry Analysis 75
xiii
4.7 Differential Scanning Calorimetry Analysis 80 4.8 Dynamic Mechanical Properties of Composites 82 4.8.1 Storage Modulus of Composites 82
4.8.2 Loss Modulus of Composites 85 4.8.3 Tan Delta of Composites 87 4.9 Scanning Electron Microscopy 89 4.10 Ageing Tests 92 4.10.1 Water Sorption 92 4.10.1.1 Water Uptake of Composites 92 4.10.1.2 Effect of Water Uptake on Properties of 95
Composites 4.10.1.3 Effect of Water Uptake on Surface Morphology 100 of Composites 4.10.2 Chemical Resistance 102
4.10.2.1 Weight Loss of Samples 102 4.10.2.2 Effect of Chemicals (HCl and NaOH) on Tensile 103 Strength of Composites 4.10.3 Biodegradation Test 105 4.10.3.1 Weight Loss of Samples 105
5 CONCLUSIONS AND RECCOMENDATIONS
5.1 Conclusions 109 5.2 Recommendations 112
REFERENCES 114 BIODATA OF THE AUTHOR 123
xiv
LIST OF TABLES
Table Page 1.1 Growth of the oil palm trade ('000t) 6 1.2 Chemical composition of oil palm fibres and some important natural 9
fibres
1.3 The fibre morphology of oil palm trunk compared to other fibres 10
1.4 Projected demand and supply situation in Malaysia 12
1.5 Application of plastic by percentage in Malaysia 12
2.1 Value for the surface tension of plastics and cellulose based materials 21
2.2 Tensile properties of PP/Hemp and PP/Hemp/PP-g-GMA properties 29
2.3 The effect of boiling water on Young's modulus and elongation at 32 break of the composite with different fibre loadings and chemical
treatments after exposure in boiling water for 7 hours
3.1 Typical properties of polypropylene (PP) 39
3.2 The properties of EBNR 7467,00 ethylene-butene copolymer 40
3.3 Composition of samples prepared 42
4.1 Weigth loss of samples at different temperature after 28 days 103 immersion in different media solutions
xv
LIST OF FIGURES Figure Page
1.1 The empty fruit bunch (EFB) photograph 8
1.2 General formula of plastic 11
2.1 Role of compatibilizing agent at the interface between natural filler 23 and matrix polymer
4.1 FTIR spectra for PP, OPEFB and OPEFB:PP composites 53
4.2 FTIR spectra for OPEFB:PP composites with EBNR 54
4.3 Effect of fibre loading on tensile strength of OPEFB:PP composites 56 for different size of fibre
4.4 Effect of fibre loading on tensile modulus and percentage of elongation 59 at break of OPEFB:PP composites for different size of fibre
4.5 Effect of rotation time on tensile strength 60
4.6 Effect of rotor speed on tensile strength 61
4.7 Effect of blending temperature on tensile strength 62
4.8 Effect of EBNR loading on tensile strength for different particle size 63 and percentage of fibre
4.9 Effect of EBNR loading on tensile modulus for different particle size 64 and percentage of fibre
4.10 Effect of EBNR on percentage of elongation at break for different 64 particle size and percentage of fibre
4.11 Effect of fibre loading and particle size on flexural strength OPEFB:PP 66 composites 4.12 Effect of fibre loading and particle size on flexural modulus OPEFB:PP 67 composites 4.13 Effect of EBNR loading on flexural strength for different particle size 68
and percentage of fibre
4.14 Effect of EBNR loading on flexural modulus for different particle size 69 and percentage of fibre
xvi
4.15 Izod impact test as a function of the fibre loading for notched OPEFB:PP 70 Composites
4.16 Izod impact test as a function of the fibre loading for unnotched 71 OPEFB:PP composites
4.17 Effect of EBNR loading on impact strength of notched samples 74
4.18 Effect of EBNR loading on impact strength of unnotched samples 74
4.19 TG and DTG thermograms of OPEFB 76
4.20 TG and DTG thermograms of OPEFB:PP composite of 40% of OPEFB 77
4.21 TG and DTG thermograms of OPEFB:PP with EBNR composite 78
4.22 Thermogravimetry of composites 79
4.23 DSC curves of OPEFB 80
4.24 DCS curves of OPEFB:PP composite 81
4.25 Influence of fibre content and size on storage modulus of PP 83
4.26 Influence of fibre content and EBNR loading on storage modulus 84 of composites
4.27 Influence of fibre content and size on loss modulus of PP 85
4.28 Influence of fibre content and EBNR loading on loss modulus of 86 composites
4.29 Influence of fibre content and size on tan delta of PP 87
4.30 Influence of fibre content and EBNR loading on tan delta of 88 composites
4.31 SEM micrographs of fracture surfaces of OPEFB:PP composite at 90 (a) 50x and (b) 300x magnifications
4.32 SEM micrographs of fracture surfaces of OPEFB:PP with EBNR 91 composite at (a) 50x and (b) 300x magnifications
4.33 Effect of OPEFB loading and particle size of fibre on water uptake 93
4.34 Effect of EBNR loading on water uptake in composites with 20% 94 of fibre loading
4.35 Effect of EBNR loading on water uptake in composites with 40% 95 of fibre loading
xvii
4.36 Effect of water uptake on tensile strength of composites 97
4.37 Effect of water uptake on tensile modulus of composites 98
4.38 Effect of water uptake on elongation at break of composites 98
4.39 Effect of water uptake on tensile strength of composites with EBNR 99
4.40 SEM micrograph of OPEFB:PP composite (a) before ageing; 100 (b) after ageing at 300x magnification
4.41 SEM micrograph of OPEFB:PP composite with EBNR (a) before 101 ageing; (b) after ageing at 300x magnification
4.42 Tensile strength of composites after immersion in HCl and NaOH 104
4.43 Weight loss of neat PP and OPEFB:PP composites during the burial 106 test in soil
4.44 Weigth loss of OPEFB:PP composites for 20% of OPEFB with 107 different EBNR loading during the burial in soil
4.45 Weigth loss of OPEFB:PP composites for 40% of OPEFB with 108 different EBNR loading during the burial in soil
xviii
LIST OF ABBREVIATIONS/NOTATION/GLOSSARY OF TERMS
ABS Acrylonitrile-butadiene-styrene
AS (3-aminopropyl)-triethoxysilane
ASTM American Standard for Testing and Materials
BGRP Bamboo fibre reinforced polypropylene composite
CPE Chlorinated polyethylene
DMA Dynamic mechanical analysis
DSC Differential scanning calorimetry
DTG Differential thermogravimetry
EBNR Ethylene-butene copolymer
EFB Empty fruit bunch
EPDM Ethylene/propylene/diene copolymer
EPDM-MAH Maleated ethylene/propylene/diene copolymer
EPM Ethylene/propylene copolymer
EP-MAH Maleated ethylene-propylene
EVA Ethylene/vinyl acetate
FFB Fresh fruit bunch
FTIR Fourier transform infrared
GF Glass fibre
GMA Glycidyl metacrylate
GP/PP Glass fibre-polypropylene composite
HCl Hydrochloric acid
HDPE High density polyethylene
LDPE Low density polyethylene
xix
LF/PP Luffa fibre-polypropylene composite
MAPP Maleic anhydride-polypropylene
MMA Methyl metacrylate
MPOB Malaysian Palm Oil Bard
MS 3-(trimethoxysilyl)-1-propanethiol
NaOH Sodium hydroxide
NBR Acrylonitrile/butadiene elastomer
OPEFB Oil palm empty fruit bunch
OPEFB:PP Oil palm empty fruit bunch-polypropylene composite
PE Polyethylene
PE/WF Polyethylene-wood fibre composite
PET Polyester
PIB Polyisobutylene
PLA Poly-lactic acid
PMMA Polymethyl metacrylate
PORIM Palm Oil Research and Development Board
PP Polypropylene
PP/RNFC Polypropylene-recycled newspaper cellulose fibre
PP/WF Polypropylene-wood fibre composite
PPG Polypropylene glycol
PP-g-GMA Polypropylene grafted glycidyl metacrylate
PS Polystyrene
PVC Polyvinyl chloride
R&D Research and development
RNFC Recycled newspaper cellulose fibre
xx
xxi
SBS Styrene-butadiene-styrene
SEBS-MAH Maleated styrene-ethylene/butadiene-styrene
TDI Toluene diisocyanate
TDI/PPG Toluene-2,4-diisocyanate/polypropylene glycol
Tg Glass transition
TG Thermal gravimetric
TGA Thermogravimetric analysis
Tm Melting temperature
TPO Ethylene/propane thermoplastic elastomer
UV Ultra-violet
WPC Wood-plastic composite
CHAPTER 1
INTRODUCTION
1.1 Background of Study
Advanced in science and technology pose new challenges in relation to certain
environmental issues, such as biodegradability, recyclability, eco-friendliness etc., that
needs to be addressed to help preserve and protect our environment. Composite
materials from the annually renewable natural fibres and biodegradable matrices have
been developed in the past decades in an attempt to find alternatives to the fossil fuel-
based polymeric materials in the automotive and packaging industries.
The benefits offered by lignocellulosic materials include making the final product lighter
and decreasing the wear of the machinery used in the production process. Moreover,
lignocellulosic materials have the advantages of low cost, biodegradability and the
absence of residues or toxic byproducts, whereas inorganic materials such as glass fibre,
carbon fibre, talc, clay, synthetic fibre, etc. do not have these benefits (Yang et al., 2004;
Lee et al., 2004). Yet another attraction of using these materials is the fact that it would
allow various agro-wastes to be appropriately recycled.
The performance and properties of composite materials depend on the properties of the
individual components and their interfacial compatibility. To ensure appropriate
interfacial interactions their surface properties must be modified accordingly.
1