MECHANICAL PROPERTIES OF WOOD PLASTIC
COMPOSITE (WPC) MADE OF RECYCLED HIGH
DENSITY POLYETHYLENE (HDPE) AND RECYCLED
WOOD FLOUR (RWF)
NANTHA S/O MUNIANDY
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
Mechanical Properties of Wood Plastic Composite (WPC) Made of
Recycled High Density Polyethylene (HDPE) and Recycled Wood
Flour (RWF)
Thesis submitted in accordance with the requirements of the
Universiti Teknikal Malaysia Melaka for the Degree of
Bachelor of Manufacturing Engineering
(Engineering Material)
By
NANTHA S/O MUNIANDY
UTeM Library (Pind.1/2007)
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
BORANG PENGESAHAN STATUS TESIS*
JUDUL: _______________________________________________________________
_______________________________________________________________
_______________________________________________________________
SESI PENGAJIAN: _______________________
Saya
_____________________________________________________________________
mengaku membenarkan tesis (PSM/Sarjana/Doktor Falsafah) ini disimpan di
Perpustakaan Universiti Teknikal Malaysia Melaka (UTeM) dengan syarat-syarat
kegunaan seperti berikut:
1.
Tesis adalah hak milik Universiti Teknikal Malaysia Melaka .
2.
Perpustakaan Universiti Teknikal Malaysia Melaka dibenarkan membuat salinan
untuk tujuan pengajian sahaja.
3.
Perpustakaan dibenarkan membuat salinan tesis 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)
(TANDATANGAN PENULIS)
Alamat Tetap:
Tarikh: _______________________
Disahkan oleh:
(TANDATANGAN PENYELIA)
Cop Rasmi:
Tarikh: _______________________
* Tesis dimaksudkan sebagai tesis bagi Ijazah Doktor Falsafah dan Sarjana secara penyelidikan, atau disertasi bagi pengajian secara kerja kursus dan penyelidikan, atau Laporan Projek Sarjana Muda (PSM). ** Jika tesis ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa/organisasi berkenaan dengan menyatakan sekali sebab dan tempoh tesis ini perlu dikelaskan sebagai SULIT atau TERHAD.
MECHANICAL PROPERTIES OF WOOD PLASTIC COMPOSITE
(WPC) MADE OF RECYCLED HIGH DENSITY POLYETHYLENE
(HDPE) AND RECYCLED WOOD FLOUR (RWF)
NANTHA A/L MUNIANDY
737-D JLN KUALA BENUT, SUNGAI KARANGAN,
09410 PADANG SERAI,
KEDAH DARUL AMAN
FAKULTI KEJURUTERAAN PEMBUATAN
Rujukan Kami (Our Ref) : 30 April 2008
Rujukan Tuan (Your Ref):
Pustakawan
Perpustakawan Universiti Teknikal Malaysia Melaka
UTeM, Ayer Keroh
MELAKA.
Saudara,
PENGKELASAN TESIS SEBAGAI SULIT/TERHAD
- TESIS SARJANA MUDA KEJURUTERAAN PEMBUATAN (BAHAN KEJURUTERAAN):
NANTHA A/L MUNIANDY
TAJUK: MECHANICAL PROPERTIES OF WOOD PLASTIC COMPOSITE (WPC) MADE
OF RECYCLED HIGH DENSITY POLYETHYLENE (HDPE) AND RECYCLED WOOD
FLOUR (RFW)
Sukacita dimaklumkan bahawa tesis yang tersebut di atas bertajuk
“Mechanical Properties of Wood Plastic Composite (WPC) Made of
Recycled High Density Polyethylene (HDPE) and Recycled Wood Flour
(RFW)”
mohon dikelaskan sebagai terhad untuk tempoh lima (5) tahun dari
tarikh surat ini memandangkan ia mempunyai nilai dan potensi untuk
dikomersialkan di masa hadapan.
Sekian dimaklumkan. Terima kasih.
“BERKHIDMAT UNTUK NEGARA”
Yang benar,
INTAN SHARHIDA BINTI OTHMAN
Pensyarah,
Fakulti Kejuruteraan Pembuatan
06-2332421
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
Karung Berkunci 1200, Ayer Keroh, 75450 Melaka Tel : 06-233 2421, Faks : 06 233 2414
DECLARATION
I hereby, declared this thesis entitled “Mechanical Properties of Wood Plastic
Composite (WPC) Made of Recycled High Density Polyethylene (HDPE) and
Recycled Wood Flour (RWF)” is the results of my own research except as cited in
references.
Signature : ……….
Author’s Name : ……….
Date : ………. 1 MAY 2008
APPROVAL
This Thesis submitted to the senate of UTeM and has been as partial fulfillment of
the requirements for the degree of Bachelor of Manufacturing Engineering
(Engineering Material). The members of the supervisory committee are as follow:
………
ABSTRACT
The goal of our research was to value add the waste material, to compare the
mechanical properties and to find the best optimum ratio between the PE and wood
flour. In this study, Wood Plastic Composite (WPC) fabricated using virgin material and
post-consumer high density polyethylene (PE) and wood flour using a twin-screw
extruder and hot compression machine. The tests of composite based on wood flour at
three different ratio filler content, 20%, 30% and 40%, were carried out using universal
tensile machine and impact tester according to ASTM D 3039, ASTM D 790 and ASTM
D 6110 respectively and their result were presented. To improve the interfacial adhesion
between the wood fiber and the HDPE, silane was used in same quantity level as
modifiers to treat wood fiber and the results are presented. The experiment results
showed that tensile and flexural properties of the composite increased with the increase
of the wood flour particles. This result is totally opposite for the impact test. The effects
of different material used and wood fiber length on the mechanical properties of WPC
were investigated and presented. Tensile fracture surfaces of tested WPC samples were
examined by using SEM and the fracture mechanism of WPC was also analyzed in this
research. From the research done we identified that the better tensile strength is
(19.24 MPa) for recycled WPC, flexural strength (50.75 MPa) for non-recycled WPC
and impact energy is (1.45 KJ/m2) for recycled WPC. As a conclusion regarding the
mechanical properties, it is shown that 30% is the optimal filler content for both type
of WPC. As overall observation the result shows that recycled WPC has better
ABSTRAK
Matlamat kajian kita adalah megkaji dan menambah nilai bahan buangan serta
mencari formulasi optimum terbaik diantara serbuk kayu dan plastic. Dalam kajian
ini, komposit panel yang berasaskan kayu dihasilkan dengan mengunakkan mesin
penyempritan skru berkembar dan mesin penekan. Ujian panel komposit berasaskan
serbuk kayu ini dilakukan pada tiga komposisi gentian kayu yang berlainan, iaitu
20%, 30% dan 40%, dimana dengan menggunakan mesin penguji tegangan dan
mesin penguji kesan daya menurut piawaian ASTM D 3039, ASTM D 790 dan
ASTM D 6110. Keputusan ujian ini turut dibincangkan dalam kajian ini. Untuk
mengukuhkan pelekatan antara gentian kayu and plastik (HDPE), “silane” telah
digunakan dalam kuantiti yang sama untuk semua komposisi bagi merawat serbuk
kayu dan keputusannya juga dibincangkan. Hasil kajian ini menunjukkan bahawa
ciri-ciri kekuatan lenturan dan tegangan selari meningkat apabila partikel serbuk
kayu meningkat. Keputusan ini adalah terbalik bagi ujian hentaman. Kesan
pengunaan bahan dan gentian kayu yang panjangnya berlainan dalam ciri-ciri
mekanikal, komposit panel kayu dikaji dan dibincang dalam kajian ini. Permukaan
bahagian patah pada sampel ujian lenturan dikaji dengan menggunakan mikroskop
elektron pengskanan dan mekanisma retak turut dibincangkan dalam kajian ini. Hasil
daripada kajian ini, kita dapat tahu bahawa kekuatan tegangan yang baik adalah
19.24 MPa untuk komposit panel kayu yang dikitar semula, kekuatan lenturan yang
baik adalah 50.75 MPa untuk komposit panel kayu semula jadi dan Kekuatan
hentaman yang baik adalah 1.45 KJ/m2 untuk komposit panel yang dikitar semula.
Kesimpulan daripada ciri-ciri mekanikal, nilai optimum gentian untuk serbuk kayu
adalah sebanyak 30%. Secara pemerhatian keseluruhan hasil kajian ini menunjukkan
sampel yang menggunakan bahan kitar semula mempunyai ciri-ciri mekanikal yang
DEDICATION
ACKNOWLEDGEMENTS
By the Grace of God, finally I have completed my thesis based on the knowledge and
experience that I got during my entire project. Here I would like to take this
opportunity to thank the people for their utmost help and guidance given to me. I
sincerely appreciate the following people for their utmost cooperation to me during
my project flow.
¾ Dean, Head of Department, Lecturers and Technician of Manufacturing
Engineering Faculty who had always given me their undivided guidance and
corrected my mistakes during doing my PSM.
¾ I extend my appreciation to the respective Pn. Intan Sharhida bt Othman, my
project supervisor who has shared her knowledge and experience as well as
give me information and also given me full support and guidance in order to
build my confidence and ability while doing my project.
¾ My panel lecturers who will conduct the secondary evaluation for my PSM
¾ Last but not least, my Colleagues who were always keep in touch and guide
me during the project.
This project is dedicated to everyone who was involved while I am doing the project
because without his or her help and support, I would not have been able to create this
TABLE OF CONTENT
Declaration………... Approval………... Abstract……… Abstrak……… Dedication……… Acknowledgement………...Table of Content………...
List of Figures………..
List of Tables………...
List Of Abbreviations, Symbols, Specialized Nomenclature……….. i ii iii iv v vi vii viii ix iix
1. INTRODUCTION………..
1.1 Problem background………...
1.2 Problem statement……….………..
1.3 Objective ………
1.4 Scope of the project……….…..………..
1.5 Study Benefit ……….. 1 1 2 3 4 4
2. LITERATURE REVIEW……….………...
2.1 Wood Plastic Composite………...
2.1.1 Wood Plastic Composite Feedstocks………
2.1.1.1 Wood………. ………
2.1.1.2 Plastic……….
2.1.1.3 Compounded Pallets………...………
2.1.1.4 Additives………...……
………
2.1.2 Manufacture of Wood Plastic Composite...……..
………
2.1.2.1 Compounding……….………
2.1.2.2 Extrusion……...……….………….…………...
2.1.3 Material Preparation………
2.1.3.1 Cleanliness of Plastic………..
2.1.3.2 Physical Form of the Plastic………
2.1.3.3 Cleanliness of the Wood……….
2.1.3.4 Physical Form of the Wood………
2.1.3.5 Particle Size of Wood Flour………
2.1.3.6 Moisture Content of the Wood………
2.1.3.7 Species of the Wood………...
2.1.4 Properties of Wood Plastic Product………..
2.2 Recycling Wood Plastic Composite
…
………...2.2.1 Introduction………...
2.2.1.1 Use of Recycled Material in WPC’s………..
2.2.1.2 Wood Based Material……….
2.2.1.3 Recycled Plastic in WPC’s……….
2.2.1.4 Potential for use of other recycled sources...
2.2.1.5 Raw Material Effects………..
2.2.1.6 Processing Effects………..
2.2.1.7 Environmental Effects………
2.2.2 Recycled Plastic Feedstocks for Composites………
2.2.2.1 Number 1 (PET or PETE)………...
2.2.2.2 Number 2 (HDPE)………..
2.2.2.3 Number 3 (PVC)……….
2.2.2.4 Number 4 (LDPE)………...
2.2.2.5 Number 5 (PP)………
2.2.2.6 Number 6 (PS)………
2.2.2.7 Number 7 (Other)………
2.2.3 Recycled Wood Feedstocks for Composites……….
2.2.3.1 Primary Wood Wastes………
2.2.3.2 Secondary Wood Wastes………
2.2.3.4 Urban Forest Residues………
2.3 Composite………..……...
2.3.1 Polymer Matrix Composite………...………...
2.3.2 Constituents of Fiber Reinforcement Composite………. ….……..
2.3.2.1 Fiber………
2.3.2.2 Matrix……….
2.3.3 Manufacturing Techniques………...
2.4 Previous Research on Wood Plastic Composite……….
2.4.1 Some of the properties of wood plastic composites………..
2.4.2 Polypropylene/wood flour composites: treatment and properties………….
2.4.3 Properties of wood plastic composites made of recycled HDPE and wood
flour from CCA-treated wood removed from service………...
2.4.4 Wood flour filled PP composite: Compatibilization and adhesion………...
3. METHODOLOGY………...………..
3.1 Introduction….……….………...
3.1.1 Flow Chart……….………
3.2 Sample Preparation………..………...
3.2.1 Thermoplastic Polymer (HDPE)………...
3.2.2 Wood Flour………...
3.2.3 Mould Fabrication……….
3.2.4 Compounding Process………...
3.2.5 Crushing Bulk Material……….
3.2.6 Hot Press………...
3.3 Test Procedure for Evaluating Wood Plastic Composite………
3.3.1 Introduction………...
3.3.2 Tensile Testing………..
3.3.2.1 Testing Scope………..
3.3.2.2 Summary of Test Method………...
3.3.2.3 Tensile Testing Procedure………...
3.3.3 Flexural Testing………
3.3.3.2 Summary of Test Method………...
3.3.3.3 Flexural Testing Procedure……….
3.3.4 Impact Testing………..
3.3.4.1 Testing Scope……….
3.3.4.2 Summary of Test Method………..
3.3.4.3 Impact Testing Procedure………...
3.4 Microstructure Observation………
3.4.1 Procedure to use the SEM………
3.5 Conclusion………..
4. RESULT AND DISCUSSION………..
4.1 Data Analysis………..
4.1.1 Mechanical Testing………...
4.1.1.1 Tensile Testing………
4.1.1.2 Flexural Testing………..
4.1.1.3 Impact Testing…...
4.1.2 Mechanical Properties of the WPC ……….
4.1.3 Comparison between Recycle and Non-Recycled WPC samples testing
Outcome………
4.2 Morphology Analysis……….
4.2.1 SEM Examination on Tensile Fracture Surface………
4.2.2 Relationship between SEM photo and Mechanical Properties……….
4.2.3 SEM Examination on Wood Flour Particle Structure………..
4.3 Challenges on processing methods……….
4.4 Characteristics Influence the WPCs properties………..
4.4.1 Influence of Aspect Ratio……….
4.4.2 Influence of Particle Size……….. ………..
4.4.3 Dispersion of the Fiber……….
4.4.4 Influence of Fiber Orientation………..
4.4.5 Influence of Coupling Agents………...
5. CONCLUSION AND RECOMMENDATIONS……….
5.1 Conclusion………..
5.2 Recommendation………
5.2.1 Research………
5.2.2 Commercialization………
REFERENCE……….
APPENDIX……….
A Gantt chart for PSM 1& 2……….
B Formulas & Calculation……….………...
C Testing Results………..
D Tensile Testing Graph………... 104
104
105
105
106
LIST OF FIGURES
2.1 Clockwise from top left: virgin polyethylene pellets, wood flour,
and wood plastic composite pellets
6
2.2 Schematic layout of Conex wood extruder 16
2.3 Woodtruder extrusion system showing material feeding
systems, extruders and cooling tank
17
2.4 Pultrusion die design for wood plastic composites 18
2.5 Effect of plastic type (polyethylene o, polypropylene ǻ,
polystyrene ×) and wood loading levels on properties of wood
plastic composites
26
2.6 Effect of plastic type on critcal properties in polypropylene,
polyethylene, and general purpose polystryrene with different
wood loading levels
37
2.7 Typical Composite 42
2.8 Illustrating the combined effect on Modulus of the addition of
Fibres to a resin matrix
44
3.1 WPC’s Manufacturing Process Flow Chart 55
3.2 Virgin Polyethylene (HDPE) Materials 57
3.3 Post consumer milk bottles 57
3.4 Virgin Wood Flour 58
3.5 Recycle Wood Flour 58
3.6 Rectangular Mild Steel Plate Mold 59
3.7 Co-Rotating Twin screw Extruder (Polylab Extruder OS, HAAKE
Rheomix OS)
61
3.8 General setting on HAAKE PolySoft OS monitor 62
3.9 Bulk Shape of WPC 63
3.10 Blend Material after Crushing (Pallet Form) 63
3.12 Dimension of Tensile Specimen 67
3.13 General Tensile test setup 68
3.14 Flexural Test Sample Dimension 70
3.15 General flexural test setup 71
3.16 Charpy V-notch specimen 73
3.17 General Charpy V-notch test setup 74
3.18 Scanning Electron Microscope (Model EVO 50) 75
4.1 Tensile Strength for Recycled and Non-Recycled WPC 78
4.2 Tensile Modulus for Recycled and Non-Recycled WPC 79
4.3 Flexural Strength for Recycled and Non-Recycled WPC 81
4.4 Flexural Modulus for Recycled and Non-Recycled WPC 82
4.5 Impact Energy (KJ/m2) of the Recycled and Non-Recycled WPC 84
4.6 Fracture surface of Tensile specimen for 20% filler in Recycle WPC
along force direction by SEM with magnification of 500 X.
90
4.7 Fracture surface of Tensile specimen for 20% filler in Non-Recycled
WPC along force direction by SEM with magnification of 500 X.
90
4.8 Fracture surface of Tensile specimen for 30% filler in Recycled
WPC along force direction by SEM with magnification of 500 X
91
4.9 Fracture surface of Tensile specimen for 30% filler in Non-Recycled
WPC along force direction by SEM with magnification of 500 X
91
4.10 Fracture surface of Tensile specimen for 40% filler in Recycled
WPC along force direction by SEM with magnification of 500 X
92
4.11 Fracture surface of tensile specimen for 40% filler in Non-Recycled
WPC along force direction by SEM with magnification of 500 X
92
4.12 Fracture surface of Tensile specimen’s microstructure for Recycled
WPC at maximum stress
93
4.13 Fracture surface of Tensile specimen’s microstructure for Non-
Recycled WPC at maximum stress
94
4.14 SEM micrograph showing the Recycle Wood fiber used in the study. 96
4.15 SEM micrograph showing the Non-Recycled Wood fiber used in the
study
LIST OF TABLES
2.1 Dimensions and Chemical Composition of some Common
Agro-Fibers
9
2.2 Effect of Pine Wood Flour Particle Size on Performance of
Wood-filled
Polypropylene Composite
22
2.3 Effects of Wood Species on Performance of Wood-filled
Polypropylene Composites
24
2.4 Post Consumer Plastics 38
3.1 Ratio of the raw material and additive agent used for panel
manufacture
60
3.2 Standard Dimension for Rigid and Semirigid Plastics, ASTM D638.
(Tensile Specimen)
67
4.1 Tensile Strength of the Recycled and Non-Recycled WPC (MPa) 77
4.2 Tensile Modulus of the Recycled and Non-Recycled WPC (GPa) 79
4.3 Flexural strength of the Recycled and Non-Recycled WPC (MPa) 81
4.4 Flexural Modulus of the Recycled and Non-Recycled WPC (GPa) 82
LIST OF ABBREVIATIONS, SYMBOLS, SPECIALIZED
NOMENCLATURE
WF - Wood Flour
HDPE - High Density Polyethylene
RWF - Recycled Wood Flour
WPC - Wood Plastic Composite
PMC - Plastic Matrix Composite
PP - Polypropylene
PVC - Polyvinylchloride
PS - Polystyrene
LDPE - Low Density Polyethylene
PET - Polyethylene teraphthalate
GPS - General Purpose Polystyrene
HIPS - High Impact Polystyrene
MAH - Maleic anhydride
SSE - Single Screw Extruder
CTSE - Co-Rotating Twin Screw Extruder
CRTSE - Counter Rotating Twin Screw Extruder
MSW - Municipal Solid Waste
SPI - Society for the Plastic Industry
SEM - Scanning Electron Microscope
UTM - Universal Testing Machine
MOR - Modulus of Rupture
MOE - Modulus of Elasticity
1
CHAPTER 1
INTRODUCTION
1.1
Project Background
In today’s modern age, there has been a large leap in development of mankind from the
beginning of this race. Due to this rapid improvement, the needs of human increases
from day to day in order to improve the quality of life. Regarding to this, many product
or equipment have been invented to make human life more comfortable and easy. As
time passes, all of this equipment wears of due to constant usage or improvement on the
product itself causing all of them to be thrown as a waste.
Usually people will ignore the left over or wastage material, for example plastic chairs
and wooden table. These things will end up in the dumping site without knowing the real
usage or benefits behind them. Besides wastage, this material can cause serious
environmental effect since some of the materials produced are non-biodegradedable.
Materials such as this will not decomposed even after few years. It is a waste not to
recycle these materials since recycling can help to lower the cost of production to so that
it can be utilized by every walk of life poor nor rich and in the same time protect the
environment.
Realizing its potential, this project will focuses on developing a wood plastic composite
(WPCs) from recycled plastic and recycled wood flour. At the same time, this project
2
material) and first generation material (non-recycle or virgin material). From the
development of this new composite, analysis as well as further research will also be
done to determine whether this material can be recycled again.
In our research, we will use both virgin and post consumer materials. The High Density
Polyethylene (HDPE) functions as the polymer matrix and wood flour as the filler. The
recycled HDPE is obtained from crushed milk bottle and the wood flour gets from post
consumer wood products. In order to do a through research, a few testing will be done
on the panel itself such as Tensile testing, Flexural testing and Impact testing in order to
observe its mechanical properties. From the series of testing the behavior of wood
plastic composite (WPCs) will be observe such as tensile strength, yield point and
Modulus of Elasticity (MOE). This data will help to determine the capability of the
material as well as identify the best formulation in order to commercialize the recycled
products.
1.2
Problem Statements
Currently the amount of garbage or waste is increasing day after day as the world’s
population increases. If we see closely, most of the wastes are from the things that we
used daily such as plastic and paper. Due to the increasing number of mankind in the
world, more products have to be manufactured to cater the needs of every human being.
These cause natural resources such as wood and petroleum to deplete fast.
Realizing this, recycling is introduced as a way to curb the problems that arise. By
recycling natural resources can be preserved for future use and in the same time protect
the environment such as forest that gives oxygen for human to life. Recycling also
reduces amount of waste produce and can help to encounter garbage accumulation
problem. Recycling also reduces cost since manufacturing product from raw material to
3
To overcome this problem, this study is done in order to develop composite from
recycled material such as wood flour and plastic. So from this combination of wood
flour and plastic, it is known as Wood Plastic Composite (WPC). By doing this research,
a deeper study on the properties of WPCs can be done in order to develop and improve
the usage of this composite in the future.
1.3
Objectives
(a) To find the best formulation of recycled HDPE and WF in order to produce
high strength WPC.
(b) To compare the mechanical properties of composites made from
non-recycled and non-recycled waste woods and plastics.
(c) To convert recycled wood fiber and recycled plastic into durable product that
4
1.4
Scope of Project
(a) Characterization of non-recycled and recycled wood flour and HDPE.
(b) Grinding and sieving of the recycled wood flour and HDPE in order to get
the desired sizes
(c) To find the best formulation of non-recycled and recycled WF and HDPE in
order to get high strength WPC.
(d) Fabrication of WPC involving certain process such as compounding, hot etc.
(e) To study the influence of blending formulation to mechanical properties and
microstructure of the composite.
1.5
Study Benefit
This research provides vast knowledge and information to all future researchers around
the world. Some of the benefits can be acquired through this research are:-
(a) From the experiment and testing done, the result can provide information
which answers all or some doubt regarding to the newly developed recycled
composite especially in terms of its properties.
(b) By this research, new acquired information can encourage more researchers
to keep on going improving the composite produce as well as develop other
new form of composite from recycled materials.
(c) This research also acts as a guide line for future researchers to do test as well
as develop new composites and testing equipment to aid the study and R&D
that will be done in the future.
Hopefully from the benefits listed above, more new minds can be develop in furthering
the research that have been done as well as used this research in achieving new
5
CHAPTER 2
LITERATURE REVIEW
2.1 Wood
Plastic
Composite
Wood Plastic composites (WPCs), variously known as wood fiber-plastic composites
and green composites are a new group of materials that are generating interest in many
applications. WPCs are defined as composite materials that contain wood (in various
forms) and thermoplastic polymer and do not include wood flour-thermoset plastics like
bakelite and particleboard products such as medium density fiberboard (Andrea
Wechsler, 2006). WPC products use a range of polymers such as polyethylene (PE),
polypropylene (PP) or polyvinylchloride (PVC) in various proportions along with wood
or other natural fibers to produce profiles or molded objects with the structural integrity
and workability of wood and the durability of polymers (Figure 2.1). While wood flour
or waste wood is mainly used as a cost-cutting alternative to mineral fillers like talc and
calcium carbonate, plant fibers like flax, hemp and kenaf are currently being evaluated
as environmentally friendly and low-cost alternatives for glass or carbon fibers in
