THE EFFECT OF COUPLING AGENT ADDITION TO
THE MECHANICAL PROPERTIES OF WOOD PLASTIC
COMPOSITE (WPC) MADE OF
RECYCLED HIGH DENSITY POLYETHYLENE (RHDPE)
AND RECYCLED WOOD FLOUR (RWF)
NG GUAN YAO
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
THE EFFECT OF COUPLING AGENT ADDITION TO THE
MECHANICAL PROPERTIES OF WOOD PLASTIC
COMPOSITE (WPC) MADE OF
RECYCLED HIGH DENSITY POLYETHYLENE (RHDPE) AND
RECYCLED WOOD FLOUR (RWF)
This report submitted in accordance with requirement of the Universiti Teknikal Malaysia Melaka (UTeM) for the Bachelor Degree of Manufacturing Engineering
(Engineering Materials) with Honours.
by
NG GUAN YAO
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA
TAJUK: The Effect of Coupling Agent Addition to the Mechanical Properties of Wood Plastic Composite (WPC) Made of Recycled High Density Polyethylene (RHDPE) and Recycled Wood Flour (RWF)
SESI PENGAJIAN: 2009/10 Semester 2
Saya NG GUAN YAO
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 yang termaktub di dalam AKTA RAHSIA RASMI 1972)
(Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasi/badan di mana penyelidikan dijalankan)
Alamat Tetap:
169, LEBUH PENGKALAN BARAT 12,
TAMAN PENGKALAN BARU,
31650 IPOH, PERAK
Tarikh: 25th MAY 2010
Disahkan oleh:
Cop Rasmi:
Tarikh: _______________________
DECLARATION
I hereby, declared this report entitled “The Effect of Coupling Agent Addition to the Mechanical Properties of Wood Plastic Composite (WPC) Made of Recycled High Density Polyethylene (RHDPE) and Recycled Wood Flour (RWF)” is the results of
my own research except as cited in references.
Signature : ………..
Author’s Name : NG GUAN YAO
APPROVAL
This report is submitted to the Faculty of Manufacturing Engineering of UTeM as a partial fulfillment of the requirements for the Bachelor Degree of Manufacturing Engineering (Engineering Materials) with Honours. The member of the supervisory committee is as follow:
ABSTRACT
ABSTRAK
DEDICATION
To my beloved aunty, your love and support are my greatest inspiration. Without your love and support, I could never go so far until now.
ACKNOWLEDGEMENT
I would like to thank the Faculty of Manufacturing of Universiti Teknikal Malaysia Melaka that gives me an opportunity to undertaking manufacturing course.
Besides, I would like to express my warmest thanks to my lecturer, Madam Intan Sharhida binti Othman, who is my ex PSM supervisor. She has done a great job in guiding me during the starting of this research.
Also, I would like to thank Mr. Jeefferie bin Abd Razak who is my current PSM supervisor. He is willing to guide and give me full support on my research. Without his effort and support, my research wills not success.
Meanwhile, I would like to thank Mr. Mohamad Haidir bin Maslan who marks my PSM report as my first panel. He is willing to give tolerance during my hardest time.
TABLE OF CONTENT
Abstract i
Abstrak ii
Dedication iii
Acknowledgement iv
Table of Content v
List of Tables ix
List of Figures x
List of Abbreviations xiv
1. INTRODUCTION 1
1.1 Background 1
1.2 Problem Statement 2
1.3 Objectives 3
1.4 Scope 3
1.5 Benefits of Study 4
2. LITERATURE REVIEW 5
2.1 Wood Plastic Composite (WPC) 5
2.1.1 History 5
2.1.2 Manufacturing Process 7
2.1.3 Mechanical Properties of WPC 8
2.1.3.1 Effect of Moisture Content in Wood Flour 9
2.1.3.2 Effect of the Types of Polymer 10
2.1.3.3 Effect of Coupling Agent 11
2.1.3.4 Effect of the Percentage of Wood Flour 12
2.1.3.5 Effect of Wood Flour Size 13
2.2 Coupling Agents 14
2.2.1 Silane Crosslinking Mechanism 15
2.3 Natural Fiber (Wood Flour) 16
2.4.1 Recycled Versus Virgin HDPE 18
2.5 Recycle Issues 19
2.6 Mechanical Testing 20
3. METHODOLOGY 21
3.1 Introduction 21
3.2 Materials 22
3.2.1 Recycled Plastic Packaging bag 22
3.2.2 Wood Flour 23
3.2.3 Coupling Agent 23
3.2.4 Virgin High Density Polyethylene (HDPE) Resin 23
3.3 Sequence of Research 24
3.3.1 Material Characterization 25
3.3.1.1 Characterization of Plastic Packaging Bag 25
3.3.1.2 Characterization of Wood Flour 27
3.3.2 Raw Material Preparation 27
3.3.2.1 Wood Flour 28
3.3.2.2 Plastic Packaging Bag 28
3.3.3 Matrix and Reinforcement Composition Preparation 29
3.3.4 Extrusion (Pre-Mixing) 31
3.3.4.1 Standard Operating Procedures for Extrusion Process 31
3.3.5 Pallet Preparation 32
3.3.6 Forming 32
3.3.6.1 Standard Operating Procedures for Hot Press Process 33
3.3.7 Mechanical Testing 33
3.3.7.1 Flexural Test 34
3.3.7.2 Impact Test 37
3.3.7.3 Tensile Test 39
3.3.8 Fracture Surface Analysis 41
3.3.8.1 Standard Operating Procedures for Optical Microscope 42
4. RESULT 41
4.1 Introduction 41
4.2 Material Characterization 41
4.2.1 Wood Flour 41
4.2.2 Plastic Packaging Bag’s Polymer Layer Material 44
4.3 Tensile Test 46
4.3.1 Fracture Surface Morphology Analysis 51
4.4 Impact Test 55
4.5 Flexural Test 58
5. DISCUSSION 62
5.1 Introduction 62
5.2 Effects of Process Methods 62
5.2.1 Microscopic Observation 63
5.2.2 Surface Wetting Observation 65
5.3 Effects of Coupling Agent Addition 67
5.3.1 Fracture Surface Morphology Analysis 68
5.4 Effects of Plastic Packaging Bag Addition 70 5.5 Effects of Various Percentages of Wood Flour Additions 71
6. CONCLUSION AND RECOMMENDATION 72
6.1 Conclusion 72
6.2 Recommendation 73
REFERENCES 74
APPENDICES
A Gantt Chart of Work
LIST OF TABLES
2.1 Mechanical Properties of Some Common Polymers in Room Temperature (Harper, 2003).
18
3.1 Raw material composition for WPC fabrication 30
4.1 Tensile Properties of pure HDPE and WPCs with the absence and present of CA and PPB fabricated by single way and two ways methods
48
4.2 Impact strength of pure HDPE and WPC with the absence and present of CA and PPB fabricated by single way and two ways method
56
4.3 Flexural strength of pure HDPE and WPC with the absence and present of CA and PPB fabricated by single way and two ways method
LIST OF FIGURES
2.1 The Degree of Crosslinking for X-Dry (Crosslinking, Dry) and X-Wet (Crosslinking, Wet) Composites After Various Storage Times in SA (Sauna) and Rt (Room Temperature) (Grubbström and Okman, 2009).
9
2.2 Stress–Strain Curves for All Crosslinked Composites as well as the Non-Crosslinked Control Material (Grubbström and Okman, 2009).
11
2.3 Average Values of the Relative Tensile Strength as a Function of Wood Content. (Bengtsson et al., 2005)
12
2.4 Effect of Mixing Temperature and Powder Size on Tensile Strength of WPC (Miki et al., 2009).
13
2.5 The Suggested Reaction Mechanism During: (a) Peroxide Induced Melt Grafting of Vinyltrimethoxy Silane onto Polyethylene, (b) Radical Induced Crosslinking of Polyethylene (Bengtsson et al., 2005)
15
2.6 The Hydrolysis Step (1) and Condensation Step (2) During Silane Crosslinking (Bengtsson et al., 2005).
16
2.7 Chain Configuration of HDPE, LDPE, and LLDPE (Harper, 2003).
17
3.1 Layout of the PPB 22
3.2 Flow Chart 24
3.3 FT/IR-6100 (Fourier Transform Infrared Spectroscopy, JAS.CO)
25
3.4 ATR PRO450-S/470-H Single reflection ATR accessories 26 3.5 Single screw extruder (Polylab Extruder, HAAKE
Rheomix OS)
31
3.6 Hot Press Machine (GT 7014-A) 32
3.7 Universal Testing Machine (UTM, Shimadzu) 34
3.9 Flexural Test Specimen 35
3.10 Impact Tester (MH 365) 37
3.11 Impact Test Specimen 38
3.12 Universal Testing Machine with tensile Test Equipment Setup (UTM, Shimadzu)
39
3.13 Tensile Test Specimen 40
3.14 Optical microscope (Optical Microscope, Zeiss) 41
4.1 Wood flour image under 1X of Magnification 43 4.2 First wood flour sample image under 1X of magnification 43 4.3 Spectrum search result for the external polymer layer 45 4.4 Spectrum search result for the internal polymer layer 46 4.5 Effect of CA and PPB addition and various process
methods to the tensile strength (MPa) of WPCs with varied percentages of wood flour loading where (a) is the
fabricated samples from single way method and (b) is the fabricated samples from two ways method
49
4.6 Effect of CA and PPB addition and various process methods to the tensile modulus (MPa) of WPCs with varied percentages of wood flour loading where (a) is the fabricated samples from single way method and (b) is the fabricated samples from two ways method
50
4.7 Fracture surface morphology of the WPC sample (1A1~1A4) from single way process method at 10X of magnification
52
4.8 Fracture surface morphology of the sample (1B1~1B4) with 5% CA from single way process method at 10X of magnification
52
4.9 Fracture surface morphology of the sample (1C1~1C4) with 5% CA, and 5% PPB from single way process method at 10X of magnification
53
4.10 Fracture surface morphology of the sample (2A1~2A4) from two ways process method at 10X of magnification
4.11 Fracture surface morphology of the sample (2B1~2B4) with 5% CA from two ways process method at 10X of magnification
54
4.12 Fracture surface morphology of the sample (2C1~2C4) with 5% CA, and 5% PPB from two ways process method at 10X of magnification
54
4.13 Effect of CA and PPB addition and various process
methods to the impact strength (Nm) of WPCs with varied percentages of wood flour loading where (a) is the
fabricated samples from single way method and (b) is the fabricated samples from two ways method
57
4.14 Flexural test with three points bending test setup 58 4.15 Effect of CA and PPB addition and various process
methods to the flexural strength (MPa) of WPCs with varied percentages of wood flour loading where (a) is the fabricated samples from single way method and (b) is the fabricated samples from two ways method
60
5.1 Non-homogenous dispersion of the matrix and filler at 10X of magnification (side surface of the sample 1B1) at 10X of magnification
64
5.2 Homogenous dispersion of the matrix and filler at 10X of magnification (side surface of the sample 2A4) at 10X of magnification
64
5.3 Poor surface wetting quality due to the improper mixing process from the sample fabricated by single way method (1B1 Fracture Surface) at 10X of magnification
66
5.4 Good surface wetting quality due to extrusion process from the sample fabricated by two ways method (2A2 Fracture Surface) at 10X of magnification
66
5.5 Possible covalent and/or hydrogen bonding between wood and vinyltrimethoxy silane-grafted-HDPE (Bengtsson et al. 2005)
5.6 Plastically deformed polymer matrix of sample with CA addition at the fractured surface (sample 2B3) at 10X of magnification
68
5.7 Matrix deformation pattern surrounding the filler when subjected to tensile loading (Callister 2005)
69
5.8 Fracture surface of the sample with PPB addition (sample 2C1) at 10X of magnification
LIST OF ABBREVIATIONS
ABS - Acrylonitrile Butadiene Styrene
Al - Aluminum
CA - Coupling agent
DSC - Differential Scanning Calorimeter FTIR - Fourier Transform Infrared Spectroscopy HDPE - High Density Polyethylene
LPA - Laser Particle Analyzer LDPE - Low Density Polyethylene
LLDPE - Linear Low Density Polyethylene MA - Maleic Anhydride
MA-PE - Maleated Polyethylene MAPP - Maleated Polypropylene MDPE - Medium Density Polyethylene
MPa - Mega Pascal
N - Newton
PE - Polyethylene
PET - Polyethylene Terepthalate
PMPPIC - Polymethylene-Polyphenyl-Isocyanate
PP - Polypropylene
PPB - Plastic packaging bag
rHDPE - Recycled High Density Polyethylene RPP - Recycled Polypropylene
RT - Room Temperature
SA - Sauna
SEM - Scanning Electron Microscope
TM - Tensile modulus
TS - Tensile strength
UTM - Universal Testing Machine
WF - Wood flour
CHAPTER 1
INTRODUCTION
1.1 Background
Wood plastic composite (WPC), the combination of wood fiber and polymer has been a growing interest in the development of construction and automotive industrial over the past decade. Recently, WPC applications have been extended other than automotive industry such as siding, fencing, window frames and decking. The reasons behind are that the WPC are low density, high stiffness and strength, low price, environmental friendly, less-abrasive to processing equipment, renewable, recyclable, and biodegradable. Other than that, the industries were forced by the environment awareness of people nowadays to choose natural materials as substitutes for non-renewable materials.
The main drawback in WPC production are difficult to achieve strong interfacial adhesion between wood fiber and polymer since they are hydrophilic and hydrophobic material just like water and oil which cannot be mixed together. This will leads to composites with poor durability and mechanical properties. Meanwhile, there has been a lot of researchers come across this problem by introducing coupling agent into the WPC production. From their study, they found out that the coupling agent addition will strengthen the material in terms of mechanical, surface, water absorption, etc. (Bengtsson and Oksman, 2006), (Felix and Gatenholm, 1991), (Kazayawoko et al., 1999), (Kokta et al., 1989), (Maldas and Kokta, 1994), and (Raj,
In the processing of WPC, there are two important topics shall be clearly identified as basic approach toward WPC design value determination. The first topic is the processing method which includes compounding and forming, whereby the second topic is the specific formulation of WPC parameter such as the composition of wood fiber and coupling agent. These two approaches can help to optimize the WPC mechanical properties to suit the particular application.
1.2 Problem Statement
Mankind, the unique race that exists in the earth has been a large leap in development. Due to the rapid development, million tones of waste per annum are produced from household, commercial, and industrial. Polymer waste such as polyethylene (PE) is the most likely material to be found in dumpling area. Furthermore, this material takes thousand years for degradation in the dumpling area. This was lead to the problem of insufficient dumpling area, and thus, more landfills have to be created to meet the requirement year to year. Consequently, it will cause bad scenery to the environment and ecosystem, contribute to various diseases, and also contribute to global warming.
In regard to the above problem, an alternative way to recycle the plastic packaging bags should be taken. Since the separation of polymer and metal layers in plastic packaging bags are impossible, the alternative way is to recycle and use both materials in one application. This could be done by mixing the plastic packaging bags material into the WPC parameter where the polymer layer will become the matrix and metal layer will act as additional filler which may further strengthen the mechanical properties of WPC.
1.3 Objectives
(a) To investigate the effects of coupling agent in various percentage addition to the mechanical properties of wood plastic composite (WPC).
(b) To study the effects of recycled woof flour percentage and recycled plastic packaging bag material percentage addition in WPC to the mechanical properties of WPC.
(c) To evaluate the effects of different process method to the mechanical properties of WPC.
1.4 Scope
This research will include the processing of WPC through single way method and two ways method where two ways method involves the pre-mixing process by using extruder whereas the single way method does not. Meanwhile, the material characterization process is conducted to analyze the wood flour size, wood flour density, and plastic packaging bag (PPB).
Besides, the materials involved are recycled PPB, wood flour, Silane, and virgin HDPE granules. The specific formulation of WPC will only focus on the absence and presence of coupling agent (CA), and the presence of PPB with CA. Besides, the HDPE to WF ratios are set to 9:1, 8:2, 7:3, and 6:4. The detail formulations will be discussed in methodology section.
By the way, water absorption test, thickness swelling test, degree of crosslinking test will not be included in this research. The main focus will be on the mechanical properties of WPC fabricated by 25 specific formulations.
1.5 Benefits of Study
From the analysis in this research, a lot of benefits and information could be acquired for example:
(a) Silane percentage addition in optimizing the mechanical properties of WPC. (b) Wood flour percentage addition effect to mechanical properties of WPC. (c) Alternative way to recycled complicated polymer material such as plastic
packaging bags.
(d) Recycled plastic packaging bag material usage in WPC and its effect to mechanical properties of WPC.
(e) WPC processing methods, steps, and parameter setup.
