UNIVERSITI PUTRA MALAYSIA

TRI PADUKAN PURBA

FH 2012 9

CHEMICAL MODIFICATION OF SESENDUK [Endospermum diadenum (Miq.) Airy Shaw] WOOD WITH LOW MOLECULAR WEIGHT

PHENOL FORMALDEHYDE

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CHEMICAL MODIFICATION OF SESENDUK [Endospermum diadenum (Miq.) Airy Shaw]

WOOD WITH LOW MOLECULAR WEIGHT PHENOL FORMALDEHYDE

By

TRI PADUKAN PURBA

MASTER OF SCIENCE UNIVERSITI PUTRA MALAYSIA

2012

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Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfillment of the requirement for the degree of Master of Science

CHEMICAL MODIFICATION OF SESENDUK [Endospermum diadenum

(Miq.) Airy Shaw] WOOD WITH LOW MOLECULAR WEIGHT PHENOL

FORMALDEHYDE

By

TRI PADUKAN PURBA

May 2012

Chairman : Associate Professor Zaidon Ashaari, PhD

Faculty : Forestry

Low-density wood, sesenduk (Endospermum diadenum) has great a

potential to substitute commercial timber, if its properties can be improved.

One of the potential processes to enhance the properties of this timber is

through bulking treatment with phenolic resin and rendered them insoluble in

the wood.

The objective of this study was to enhance the properties of sesenduk wood

through bulking treatment with low molecular weight phenol formaldehyde

(LmwPF, Mw = 600). The effect of initial moisture content (MC), duration of

soaking in the treating solution and incorporating urea in the PF resin on the

properties and formaldehyde emission of the treated wood were investigated.

Wood strips of dimension 10mm x 50mm x 150mm (impreg) and 20mm x

50mm x 150 mm (compreg) with initial MC of 15, 25 and >40% were

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impregnated with 15% LmwPF using a vacuum-pressure process. The

samples were left soaked under pressure for 30, 60 and 120 min. The effect

of the processing variables on the treatability of the wood was then analyzed.

After impregnation, the treated samples were partially cured at 65 °C for 6 h

and subsequently compressed to a compression ratio of 50% in a hot press

maintained at 150±2 °C for 60 min. In the second part of the study, urea

(formaldehyde catcher) at concentrations of 10, 20, and 30% (based on solid

PF) were incorporated separately in the PF resin and these mixture were

used as treating solution to treat the wood. The treatment without urea and

untreated solid wood served as controls for comparison purposes.

The results showed that the initial MC of the wood significantly (p<0.05)

affected polymer retention (PR), while soaking time affected PR and weight

percent gain (WPG) of the treated material. The highest PR and WPG were

attained by samples with initial MC of 25%. For each initial MC group,

soaking for 120 min yielded the highest PR and WPG. The results also

showed that there is positive correlation between PR and WPG.

For compreg sesenduk, initial MC significantly affects WPG while soaking

time did not have any significant effect on WPG. The highest and the lowest

WPG were at 15% and 40% of initial MC respectively.

Statistical analyses board properties showed that WPG had positive

correlation with density, and reduction in water absorption (Rabs), but

negative correlation with thickness swelling when tested soaking distilled

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water and exposure to humidity. Nevertheless, there is no significant

(p>0.05) correlation between WPG and volumetric swelling coefficient (S) or

anti-swelling efficiency (ASE) of the compreg.

Formaldehyde emission (FE) was significantly reduced when urea was

incorporated in the treating solution and the degree of reduction increased

with urea concentration. Compreg products produced with/without the

addition of urea had mechanical properties superior compared to untreated

wood; however, the swelling coefficient was inferior which was probably due

to the residual effect of the compression. When compared among the

treatment combinations, compregs produced without urea had mechanical

properties higher than those treated with the mixture.

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Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai memenuhi keperluan untuk ijazah Master Sains

KIMIA PENGUBAHSUAIAN KAYU SESENDUK [Endospermum diadenum

(Miq.) Airy Shaw] DENGAN FENOL FORMALDEHID BERAT MOLEKUL

RENDAH

Oleh

TRI PADUKAN PURBA

Mei 2012

Pengerusi : Profesor Madya Zaidon Ashaari, PhD

Fakulti : Perhutanan

Kayu berketumpatan rendah, sesenduk (Endospermum diadenum)

mempunyai potensi yang besar untuk menggantikan kayu komersial, jika

sifat-sifat kayu ini boleh diperbaiki. Salah satu proses yang berpotensi untuk

meningkatkan sifat-sifat kayu ini adalah melalui rawatan pukal dengan resin

fenolik dan menjadikan ia tidak larut di dalam sel kayu.

Objektif kajian ini adalah untuk meningkatkan sifat-sifat kayu sesenduk

melalui rawatan pukal dengan fenol formaldehid berat molekul yang rendah

(LmwPF, Mw = 600). Kesan kandungan lembapan permulaan (MC), tempoh

rendaman dalam larutan pengawet dan kesan penambahan urea dalam resin

PF ke atas sifat dan pelepasan formaldehid pada kayu yang dirawat telah

disiasat. Kayu jalur berukuran 10mm x 50mm x 150mm (impreg) dan 20mm x

50mm x 150 mm (compreg) dengan MC permulaan sebanyak 15, 25 dan

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>40% telah diimpregnasi dengan menggunakan LmwPF 15% melalui proses

vakum tekanan. Sampel-sampel dibiarkan terendam di bawah tekanan

selama 30, 60 dan 120 minit. Kesan pembolehubah pemprosesan pada

kebolehrawatan kayu telah dianalisis. Selepas diimpregnasi, sampel terawat

dimatangkan secara separa pada suhu 65ºC selama 6 jam dan kemudiannya

dimampatkan dengan nisbah mampatan sebanyak 50% dalam penekan

panas pada suhu 150±2 ºC selama 60 minit. Dalam bahagian kedua kajian

ini, urea (penangkap formaldehid) pada kepekatan 10, 20, dan 30%

(berdasarkan pepejal PF) telah dicampurkan ke dalam resin PF secara

berasingan dan campuran ini telah digunakan sebagai larutan pengawet

untuk merawat kayu. Rawatan tanpa urea dan kayu pepejal tidak dirawat

digunakan sebagai kawalan untuk tujuan perbandingan.

Keputusan menunjukkan bahawa MC awal kayu ketara (p<0.05) memberikan

kesan signifikan pada penahanan polimer (PR), manakala masa rendaman

memberikan kesan yang signifikan pada PR dan peratus penambahan berat

(WPG) bahan yang dirawat. PR dan WPG tertinggi telah dicapai oleh sampel

dengan MC permulaan 25%. Bagi setiap kumpulan MC, rendaman selama

120 minit menghasilkan PR dan WPG tertinggi. Keputusan juga

menunjukkan bahawa terdapat korelasi yang positif antara PR dan WPG.

Untuk compreg sesenduk, MC awal memberi kesan signifikan pada WPG

manakala masa rendaman tidak mempunyai apa-apa kesan yang signifikan

pada WPG. WPG tertinggi dan terendah masing-masing diperoleh pada 15%

dan 40% MC awal.

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Analisis statistik terhadap sifat papan menunjukkan bahawa WPG

mempunyai korelasi positif dengan ketumpatan, dan pengurangan dalam

penyerapan air (Rabs), tetapi berkorelasi negatif dengan pembengkakan kayu

apabila direndam dengan air suling dan didedahkan kepada kelembapan.

Walau bagaimanapun, tidak terdapat korelasi yang signifikan (p>0.05) antara

WPG dan pekali pembengkakan isipadu (S) atau kecekapan anti-

pembengkakan (ASE) compreg.

Pelepasan formaldehid (FE) telah dikurangkan dengan ketara apabila urea

telah dicampurkan ke dalam larutan pengawet dan tahap pengurangan

meningkat dengan kepekatan urea. Produk compreg yang dihasilkan dengan

atau tanpa tambahan urea mempunyai sifat-sifat mekanik terbaik berbanding

kayu yang tidak dirawat; bagaimanapun, S adalah lebih rendah yang

mungkin disebabkan oleh kesan sisa mampatan. Apabila dibandingkan

antara gabungan rawatan, compreg yang dihasilkan tanpa urea mempunyai

sifat mekanikal yang lebih tinggi daripada mereka yang dirawat dengan

campuran.

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ACKNOWLEDGEMENTS

I would like to express my deepest gratitude and appreciation to my

supervisor, Assoc. Prof. Dr. Zaidon Ashaari for his invaluable guidance,

comments, and encouragement on the entire project. I also would like to

express my appreciation to my co-supervisor, Assoc. Prof. Dr. Edi Suhaimi

Bakar for his assistance.

A special acknowledgement goes to the staff of the Faculty of Forestry, Mr.

Muhamad Azizi Mustapa, Mr. Mohamad Rizal Abdul Rahman, Mr. Rahmat

Ismail, Mr. Zamani bin Mohd. Daud, Mr. Khairul Izudin bin Hashim. My

deepest thanks to Dr. Anwar Fitrianto from Department of Mathematic,

Faculty of Science, Universiti Putra Malaysia for assisting the author on the

statistical analyzes.

I am also indebted to my beloved parents, brother, and sisters for their never-

ending love and support through the good times and through the challenging

times. My warmest gratitude also goes to my colleagues especially

Sofydzulhayry bin Mohd Noor, Chong Yi Wei, Mohamad Amarullah, Farin

Sharani and also to all member of Indonesian Student Association in UPM,

thank you for the wonderful memories. Last but not least, I would like to thank

Cynthia Yulina Dewi for her support and encouragement throughout my

study.

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I certify that an Examination Committee has met on 28 May 2012 to conduct the final examination of Tri Padukan Purba on his thesis entitled “Chemical

Modification of Sesenduk [Endospermum diadenum (Miq.) Airy Shaw] Wood with Low Molecular Weight Phenol Formaldehyde” in accordance with Universiti Pertanian Malaysia (Higher Degree) Act 1980 and Universiti Pertanian Malaysia (Higher Degree) Regulations 1981. The Committee recommends that the student be awarded the Master of Science.

Members of the Examination Committee were as follows:

Jegatheswaran A/L Ratnasingam, PhD Associate Professor Faculty of Forestry Universiti Putra Malaysia (Chairman) Mohd Zin bin Jusoh, PhD Associate Professor Faculty of Forestry Universit Putra Malaysia (Internal Examiner) Rasmina binti Halis, PhD Lecturer Faculty of Forestry Universiti Putra Malaysia (Internal Examiner)

Rokiah Hashim, PhD Associate Professor School of Industrial Technology Universiti Sains Malaysia (External Examiner)

SEOW HENG FONG, PhD

Professor and Deputy Dean School of Graduate Studies Universiti Putra Malaysia Date:

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This thesis was submitted to the Senate of Universiti Putra Malaysia and has been accepted as fulfillment of the requirement for the degree of Master of Science. The members of the Supervisory Committee were as follows:

Zaidon Ashaari, PhD

Associate Professor Faculty of Forestry Universiti Putra Malaysia (Chairman) Edi Suhaimi Bakar, PhD

Associate Professor Faculty of Forestry Universiti Putra Malaysia (Member)

BUJANG BIN KIM HUAT, PhD Professor and Dean School of Graduate Studies Universiti Putra Malaysia Date:

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DECLARATION

I declare that the thesis is my original work except for quotations and citations which have been duly acknowledged. I also declare that it has not been previously, and is not concurrently, submitted for any other degree at Universiti Putra Malaysia or at any other institution.

TRI PADUKAN PURBA

Date: 28 May 2012

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TABLE OF CONTENTS

Page

ABSTRACT ii

ABSTRAK v

ACKNOWLEDGEMENTS viii

APPROVAL ix

DECLARATION xi

LIST OF TABLES xv

LIST OF FIGURES xvi

LIST OF ABBREVIATIONS xviii

CHAPTER

1 INTRODUCTION 1

1.1 General Background 1

1.2 Problem Statement and Justification 4

1.3 Main Objective 5

1.3.1 Specific Objectives 6

2 LITERATURE REVIEW 7

2.1 Scenario of Wood Industries in Malaysia 7

2.2 Sesenduk 9

2.2.1 General 9

2.2.2 Wood Anatomy of Sesenduk 10

2.2.3 General Physical Properties of Sesenduk 11

2.2.4 Uses of Sesenduk 11

2.3 Treatments to Enhance Wood Properties 12

2.3.1 Bulking Treatments 12

2.3.2 Crosslinking 14

2.4 Phenol Formaldehyde (PF) Resin 16

2.4.1 Impregnation of Wood (Impreg) 19

2.4.2 Compregnation of Wood (Compreg) 22

2.5 Formaldehyde Emission and Admixed Urea as 25

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Formaldehyde Scavenger

2.6 Wood Modification 27

2.7 Wood Modification and Dimensional Stability 29

2.8 Weight Percent Gain and Polymer Retention 31

2.9 Mechanical Properties of Modified Wood 33

2.10 Durability of Chemical Modified Wood 36

3 MATERIAL AND METHODS 40

3.1 Materials 40

3.2 Treating Solution Preparation 40

3.3 Moisture Content Determination 41

3.4 Wood Impregnation 43

3.5 Wood Compregnation 44

3.6 Wood Compregnation Admixed with Urea 46

3.7 Treatability of Wood 47

3.7.1 Polymer Retention 47

3.7.2 Weight Percent Gain 47

3.8 Dimensional Stabilization 48

3.8.1 Anti Swelling Efficiency 48

3.8.2 Water Absorption and Thickness Swelling 50

3.8.3 Mechanical Properties Evaluation 51

3.9 Determination of Formaldehyde Emission 56

3.9.1 Reagents 56

3.9.2 Test Pieces 56

3.9.3 Sample Collection 58

3.9.4 Determination of Formaldehyde 58

3.9.5 Formaldehyde Standard Solution 59

3.9.6 Determination of the Calibration Curve 60

3.9.7 Calculation of the Concentration of 60

Formaldehyde Emission

3.10 Data Analysis 61

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4 RESULTS AND DISCUSSION 63

4.1 Wood Impregnation Treatment 63

4.1.1 Effect of Initial MC on PR and WPG 63

4.1.2 Properties of Compreg-treated Wood 68

4.2 Effect of WPG on Density and Dimensional Stability 73

of Compreg Sesenduk

4.3 Formaldehyde Emission, Dimensional Stability and 82

Mechanical Properties of Phenol Formaldehyde+Urea

(PFU)-treated Wood

4.3.1 Formaldehyde Emission from PFU-treated 82

Wood

4.3.2 Density and Dimensional Stability of PFU- 86

Treated Wood

4.3.3 Static Bending Strength of PFU-treated Wood 92

4.3.4 Compressive Stress of PFU-treated Wood 95

4.3.5 Hardness of PFU-treated Wood 96

5 CONCLUSIONS AND RECOMMENDATIONS 99

5.1 Conclusions 99

5.2 Recommendations 100

REFERENCES 102

APPENDICES 110

BIODATA OF STUDENT 120