mohd junaedy bin osman - psasir.upm.edu.mypsasir.upm.edu.my/27400/1/fs 2011 97r.pdf · pengisian...

UNIVERSITI PUTRA MALAYSIA

PREPARATION AND CHARACTERIZATION OF POLY(LACTIC

ACID)/POLY(BUTYLENE ADIPATE-CO-TEREPTHALATE)/CLAY

NANOCOMPOSITES

MOHD JUNAEDY BIN OSMAN

FS 2011 97

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NANOCOMPOSITES

By


Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia,

in Fulfillment of the Requirements for Degree of Master of Sciences

February 2011

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Abstract of thesis presented to the Senate of Universiti Putra Malaysia in

fulfilment of requirements for the Degree Master of Science



NANOCOMPOSITES

By


February 2011

Chaiman: Nor Azowa bte Ibrahim, PhD

Faculty: Science

Poly(lactic acid) (PLA) is a biodegradable plastic that is brittle. Because of this

nature, PLA has a limitation in its usage. The toughness of PLA can be improved

by adding plasticizer. In this study, poly(butylenes adipate-co-terepthalate) was

added to act as a plasticizer for PLA. The new biodegradable plastic, poly(lactic

acid)/poly(butylene adipate-co-terepththalate) (PLA/PBAT), PLA/PBAT/sodium

montmorillonite (PLA/PBAT/Na-MMT) and PLA/PBAT/organomodified

montmorillonite (PLA/PBAT/OMMT) nanocomposites were prepared by using

melt blending technique. This thesis describes the preparation and

characterization of PLA/PBAT blends, PLA/PBAT/MMT composites and

PLA/PBAT/OMMT nanocomposites.

In order to improve the compatibility of polymer and clay, the clay was first

modified to become organoclay (OMMT). The organoclays were prepared from

sodium montmorillonite (Na-MMT) through cation exchange technique using

two types of organic surfactants; octadecyl amine (ODA) and dimethyl

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dioctadecyl amine bromide (DDOAB). Cloisite 20A (C 20A) commercialize

organoclay also used to compare the effect of this organoclay to PLA/PBAT

blends. The increase in interlayer spacing of OMMT was characterized using X-

Ray Diffraction (XRD) analysis. The presence of alkylammonium ions in

organoclay was also studied by Fourier Transform Infrared (FTIR). Thermal

behaviour and amount of surfactant intercalate into the clay galleries of OMMT

was study by Thermogravimetric analysis (TGA) and elemental analysis

respectively.

In studying properties of PLA/PBAT blends, the interaction between these two

polymers will affect the tensile and mechanical properties of PLA/PBAT blends.

In this study, PBAT acts as a plasticizer of PLA whereas the addition of PBAT

decreased the tensile strength and tensile modulus of PLA however increased the

elongation at break. The interaction between PLA and PBAT was examined by

FTIR. From the dynamic mechanical analysis, PLA and PBAT form immiscible

blends as there is two peaks at loss modulus curve represented the Tg for PLA

and PBAT. This was supported by SEM observation. Water absorption of sample

was found have the same trends as the biodegradation rate of the sample. With

greater amounts of PBAT, water absorption and biodegradation rate of the

sample increase.

Since blending PLA and PBAT will result immiscible blends, OMMT is

introduce into PLA/PBAT blends system to improve the compatibility between

PLA/PBAT and OMMT. The type of modifier plays a significant role to

influence the tensile properties of PLA/PBAT/OMMT nanocomposites.

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Generally, OMMT with more polar modifier give higher tensile properties of

PLA/PBAT/OMMT nanocomposites. This was expected due to the hydrogen

bonding between PLA/PBAT blends and the hydroxyl group inside the clay

galleries. As a result, shifting for C - O group detected on FTIR spectra.

Dynamic mechanical studies revealed the same result as the tensile properties.

The addition of OMMT into PLA/PBAT blends increased the thermal

degradation as shown in TGA. SEM images show the improvement on continuity

and compatibility of PLA/PBAT/OMMT nanocomposites as the reduction of

cavity and smoother surface. Transmission electron microscopy (TEM) was used

to observe the distribution of OMMT and study the type of nanocomposite

formed. The addition of OMMT also enhances the barrier properties in term of

water absorption of PLA/PBAT/OMMT nanocomposites, which due to

increasing of tortousity. The sample was confirmed as biodegradable as it

degraded (loss in weight) after 3 weeks of biodegradable test.

The effect of clay loading on tensile properties, mechanical properties, thermal

properties, water uptake and biodegradability of PLA/PBAT blends,

PLA/PBAT/MMT composites and PLA/PBAT/OMMT nanocomposites were

discuss in term of clay loading. The optimum clay loading for PLA/PBAT blends

is 1%. The tensile strength and tensile modulus increase until 1 % clay loading

and start to decrease with increasing clay loading due to the tactoid structure at

high clay loading. The mechanical properties and thermal properties increased

with increasing clay content due to the enhancement reinforcing action between

clay and polymer and the barrier properties of the clay. The tortuous path created

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after addition of clay influenced the water uptake and biodegradability of

PLA/PBAT/OMMT nanocomposites and PLA/PBAT/MMT composites.

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Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai

memenuhi keperluan untuk Ijazah Master Sains.

PENYEDIAAN DAN PENCIRIAN NANOKOMPOSIT POLI(ASID

LAKTIK)/POLI(BUTILENA ADIPAT-KO-TEREFTALAT)/TANAH LIAT

Oleh


Februari 2011

Pengerusi: Nor Azowa Bte Ibrahim, PhD

Fakulti: Sains

Poli(asid laktik) (PLA) adalah salah satu plastik terbiodegradasi yang rapuh.

Disebabkan sifat ini, PLA penggunaannya terbatas. Kekerasan PLA boleh

ditambahbaikkan dengan menambahkan pemplastik. Dalam kajian ini,

poli(butilena adipat-ko-tereftalat) (PBAT) telah ditambah untuk bertindak

sebagai pemplastik bagi PLA. Plastik terbiodegradasi baru, Poli(asid

laktik)/poli(butilena adipat-ko-tereftalat) (PLA/PBAT), PLA/PBAT/natrium

montmorillonit (PLA/PBAT/Na-MMT) dan PLA/PBAT/organik terubahsuai

montmorillonit (PLA/PBAT/OMMT) telah disediakan menggunakan teknik

pengadunan lebur. Tesis ini menghuraikan tentang penyediaan dan pencirian

adunan PLA/PBAT, PLA/PBAT/Na-MMT komposit dan PLA/PBAT/OMMT

nanokomposit.

Untuk menambahbaikkan keserasian polimer dan tanah liat, tanah liat telah

diubahsuai menjadi organo-tanah liat (OMMT). Organo-tanah liat telah

disediakan dari natrium montmorillonit (Na-MMT) melalui teknik pertukaran

kation menggunakan dua jenis surfaktan organik; oktadesil amino (ODA) dan

dimetil dioktadesil amino bromida (DDOA). Cloisit 20A (C 20A) organo-tanah

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liat komersil juga digunakan untuk membandingkan kesan organo-tanah liat ini

kepada adunan PLA/PBAT. Penambahan pada jarak antara lapisan OMMT telah

ditentukan menggunakan analisis belauan sinar X (XRD). Kehadiran ion

alkilammonium dalam organo-tanah liat telah ditentukan menggunakan

spektroskopi infra-merah pengubah Fourier (FTIR). Kelakuan terma dan jumlah

surfaktan yang masuk ke dalam lapisan tanah liat OMMT ditentukan

menggunakan analisis termogravimetri (TGA) dan analisis unsur.

Dalam mempelajari sifat-sifat adunan PLA/PBAT, interaksi antara kedua-dua

polimer ini dipercayai mempengaruhi regangan dan sifat-sifat mekanikal adunan

PLA/PBAT. PBAT telah diketahui bertindak sebagai pemplastik kepada PLA

dimana penambahan PBAT, menurunkan kekuatan regangan dan modulus

regangan PLA namun meningkatkan nilai pemanjangan putus. Interaksi antara

PLA dan PBAT telah disiasat menggunakan FTIR. Dari analisis mekanikal

dinamik, PLA dan PBAT membentuk adunan tidak berpadu kerana wujud dua

puncak pada modulus hilang mewakili Tg untuk PLA dan PBAT. Ini disokong

dengan pemerhatian SEM. Penyerapan air oleh sampel ditemui mempunyai

kecenderungan yang sama dengan kadar biodegradasi sampel. Dengan

penambahan jumlah PBAT, penyerapan air dan kadar biodegradasi sampel juga

bertambah.

Oleh kerana mengadun PLA dan PBAT akan menghasilkan adunan tidak

berpadu, OMMT diperkenalkan ke dalam adunan PLA/PBAT untuk

menambahbaikkan keserasian antara PLA/PBAT dan OMMT. Jenis

pengubahsuai memainkan peranan yang penting dalam mempengaruhi sifat

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regangan PLA/PBAT/OMMT nanokomposit. Amnya OMMT dengan

pengubahsuai yang lebih polar menghasilkan PLA/PBAT/OMMT nanokomposit

bersifat regangan tinggi. Ini sudah dijangka kerana ikatan hidrogen antara adunan

PLA/PBAT dan kumpulan hidroksil di dalam lapisan tanah liat. Ini disahkan

dengan penganjakkan untuk kumpulan C - O dikesan pada spektra FTIR. Kajian

mekanikal dinamik membuktikan keputusan yang sama dengan keputusan sifat

regangan. Penambahan OMMT ke dalam adunan PLA/PBAT meningkatkan

degradasi termal seperti yang ditunjukkan dalam TGA. Imej SEM menunjukkan

penambahbaikkan dalam kesinambungan dan keserasian PLA/PBAT/OMMT

nanokomposit dari pengurangan jumlah lubang dan permukaan yang rata.

Mikroskop transmisi elektron (TEM) digunakan bagi memerhatikan pengagihan

OMMT dan mengkaji jenis nanokomposit terhasil. Penambahan OMMT juga

meningkatkan sifat rintangan dari sudut penyerapan air PLA/PBAT/OMMT

nanokomposit adalah kerana peningkatan keluk-keluk dalam polimer. Sampel

disahkan terdegradasi kerana terdapat penyusutan berat selepas 3 minggu dalam

ujian terbiodegradasi.

Kesan pengisian tanah liat terhadap sifat regangan, sifat mekanikal, sifat terma,

pengambilan air dan sifat biodegradasi adunan PLA/PBAT, PLA/PBAT/MMT

komposit dan PLA/PBAT/OMMT nanokomposit dibincangkan dari sudut jumlah

pengisian tanah liat. Pengisian tanah liat yang optimum untuk adunan

PLA/PBAT adalah 1%. Kekuatan regangan dan modulus regangan bertambah

sehingga 1% kandungan tanah liat dan mula berkurang dengan penambahan

kandungan tanah liat kerana struktur taktoid dalam kandungan tanah liat yang

tinggi. Sifat mekanikal dan sifat termal meningkat dengan penambahan tanah liat

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termuat disebabkan peningkatan kesan peneguhan antara tanah liat dan polimer

juga sifat rintangan tanah liat. Laluan berkelok-kelok terhasil setelah

penambahan tanah liat mempengaruhi pengambilan air dan biodegradasi

PLA/PBAT/OMMT nanokomposit dan PLA/PBAT/MMT komposit.

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ACKNOWLEDGEMENTS

Alhamdulillah, praise to Allah the Almighty for his blessing this study was

completely carried out. First and foremost I would like to express my profound

and most sincere gratitude to Dr Nor Azowa Bte Ibrahim chairman of the

supervisory committee and other member of the committee, Prof Dato Dr Wan

Md Zain Bin Wan Yunus and Dr Jamaliah Bte Sharif for their guidance,

suggestion and continuous encouragement throughout the course of this research.

I would like to acknowledge the technical staff of chemistry department, UPM

for their help in getting the TGA, CHNS, FTIR, the Bioscience Institute, UPM

for their help in getting SEM and TEM micrographs and polymer unit of Nuclear

Agency for their help in getting DMA results.

I am thankful to all my friends’ expecially Mohd Nazri Mohd Rahim, Mohd

Lokman Che Jusoh, Mohd Izwan Lazim, Mohd Fazlin Nazli, Mohd

Khairulneeza, Chieng Buong Wei, Nurazlin Amrullah, and Then Yoon Yee for

their help and advice in completing this research.

I also grateful to the UPM for giving me GRF to support my life during two

years in master course. Finally, I would like to extend my sincere gratitude to my

beloved family because of constant morale support and inspiration.

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APPROVAL

I certify that an Examination committee has met on 17 February 2011 to conduct

the final examination of Mohd Junaedy Bin Osman on his degree thesis entitled

“Preparation and characterization of poly(lactic acid)/poly(butylenes adipate-co-

terepththalate) clay nanocomposites” in accordance with Universiti Pertanian

Malaysia (Higher Degree) Act 1980 and University Pertanian Malaysia (Higher

Degree) Regulation 1981. The committee recommended that the student awarded

the degree of Master of Science.

Member of the Examination Committee were as follows:

Mansor Ahmad, PhD

Associate Professor

Faculty of Science

Universiti Putra Malaysia

(Chairman)

Mohamad Zaki Ab. Rahman, PhD

Associate Professor

Faculty of Science


(Internal Examiner)

Sidik Silong, PhD

Associate Professor

Faculty of Science


(Internal Examiner)

Ishak Ahmad, PhD

Associate Professor

School Of Chemical and Food Technology

Faculty of Science and Technology

Universiti Kebangsaan Malaysia

43600, Bangi, Selangor

Malaysia.

(External Examiner)

________________________

Shamsuddin Sulaiman, PhD

Professor and Deputy Dean

School of Graduate Studies


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 Master of Science. The

members of the Supervisory Committee were as below:

Nor Azowa Ibrahim, PhD

Associate Professor

Faculty of Science

University Putra Malaysia

(Chaiman)

Dato’ Wan Md Zin Wan Yunus, PhD

Professor

Faculty of Science


(Member)

Jamaliah Sharif, PhD

Polymer Department

Malaysian Nuclear Agency

Bangi, 43000 Kajang

Selangor,

Malaysia

_______________________________

HASANAH MOHD GHAZALI, PhD

Professor and Dean

School of Graduate Studies


Date:

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DECLARATION

I declare that the thesis is my original work except for quotation and citation,

which have been duly acknowledged. I also declare that this thesis has not been

previously and is not concurrently submitted for any other degree at Universiti

Putra Malaysia or any other institution.

_____________________________


Date: 17 February 2011

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TABLE OF CONTENTS

ABSTRACT ii

ABSTRAK vi

ACKNOWLEDGEMENT x

APPROVAL

DECLARATION

TABLE OF CONTENTS

xi

xiii

xiv

LIST OF FIGURES xvii

LIST OF TABLES xxi

LIST OF SYMBOLS AND ABBREVIATIONS xxii

CHAPTER

1 INTRODUCTION

1.1 Background of study

1.2 Research Problems

1.3 Objectives of study

1

1

3

6

2 LITERATURE REVIEW

2.1 Biodegradable Plastic

2.1.1 Poly(lactic acid) (PLA)

2.1.2 Poly(butylenes adipate-co-terepththalate)

(PBAT)

2.2 Polymer blends

2.3 Problems in polymer blends

2.4 Ways to improve miscibility of the blends

2.5 Clay modification

2.6 Preparation of nanocomposite

2.7 Properties of nanocomposites

7

7

8

10

11

14

23

26

29

30

3 MATERIALS AND METHODS

3.1 Materials

3.2 Preparation of organoclay

3.3 Preparation of PLA/PBAT blends

3.4 Preparations of PLA/PBAT Nanocomposites

34

34

34

36

37

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3.5 Characterization of organoclay

3.5.1 X-Ray Diffraction study

3.5.2 Fourier Transform Infrared spectroscopy

(FTIR) study

3.5.3 Thermogravimetric Analysis

3.5.4 Elemental Analysis

3.6 Characterization of PLA/PBAT and PLA/PBAT

nanocomposites

3.6.1 X-Ray Diffraction Study

3.6.2 Tensile Properties study

3.6.3 Fourier Transform Infrared spectroscopy

3.6.4 Dynamic Mechanical Analysis

3.6.5 Thermogravimetric Analysis

3.6.6 Scanning Electron Microscopy

3.6.7 Transmission Electron Microscopy

3.6.8 Water Adsorption Test

3.6.9 Biodegradable Test

38

38

39

39

39

40

40

40

41

41

42

42

42

43

44

4 RESULTS AND DISCUSSIONS

4.1 Preparation and characterization of organoclay

4.1.1 Interlayer spacing of Organoclay (XRD)

4.1.2 FTIR analysis

4.1.3 Thermogravimetric analysis

4.1.4 Elemental analysis

4.2 Preparation of PLA/PBAT blends

4.2.1 Tensile Properties

4.2.2 FTIR analysis

4.2.3 Dynamic Mechanical Analysis

4.2.4 Morphology characterization

4.2.5 Water absorption test

4.2.6 Biodegradability test

4.3 Characterization of nanocomposites: Effect of type of

organoclay

45

45

45

49

52

54

55

56

61

62

65

68

69

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4.3.1 XRD analysis

4.3.2 FTIR analysis

4.3.3 Tensile strength

4.3.4 Tensile modulus

4.3.5 Dynamic Mechanical properties


4.3.7 Surface morphology

4.3.8 TEM analysis

4.3.9 Water Adsorption Test

4.3.10 Biodegradability Test

4.4 Characterization of PLA/PBAT nanocomposites: Effect

of clay loading

4.4.1 XRD analysis of PLA/PBAT nanocomposites

4.4.2 Tensile strength

4.4.3 Tensile modulus

4.4.4 Dynamic Mechanical properties


4.4.6 Water absorption test

4.4.7 Biodegradability test

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75

78

79

81

85

88

91

94

96

98

99

102

104

106

110

114

117

5 CONCLUSION AND RECOMMENDATIONS

5.1 Conclusion

5.2 Recommendation for future work

121

121

124

REFERENCES 125

BIODATA OF STUDENT 139

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