abstract - umpir.ump.edu.myumpir.ump.edu.my/5122/1/cd6482.pdf · analisis morfologi, haba dan ujian...

v

ABSTRACT

Polylactic acid (PLA) has attracted much attention due to their biodegradability and

biocompatibility properties. The organically modified montmorillonite or known as

nanoclay namely Cloisite B30 (the montmorillonite modified with a quaternary

ammonium salt) was used in this research. PLA nanocomposite was prepared by melt

intercalation method. Morphological, thermal and mechanical analysis was investigated

for both pristine PLA and PLA organoclay nanocomposite. The morphological analysis

was observed using both X-ray Diffraction (XRD) and Scanning Electron Microscopy

(SEM). Thermal stability for the nanocomposites were studied using Thermogravimetric

Analysis (TGA). Glass transition temperature, Tg data has been collected and analyzed

using Differential Scanning Calorimeter (DSC). Other than that, the mechanical

properties of the nanocomposites were observed from tensile test. From this research, a

possible exfoliation of silicate layered of Cloisite B30 in the PLA matrix was

demonstrated as there were no noticeable XRD peaks was observed. SEM images could

not determine the nanoclay dispersion but the nanocomposite samples possessed large

aggregates, whose role as stress concentrators. In thermal analysis, TGA resulted in the

decrease of thermal stability with increasing loading of Cloisite B30. The glass

transition temperature for the nanocomposites also has no improvement on Tg compared

to pure PLA. Mechanical analysis of the nanocomposites was studied using Universal

Testing Machine. A poor ultimate stress and ultimate strength but more elasticity of

nanocomposites was observed compared to pure PLA.

vi

ABSTRAK

Asid Polilaktik (PLA) telah mendapat perhatian yang menggalakkan disebabkan oleh

ciri-cirinya yang biokompabiliti dan terbiodegradasi. Montmorilonit organik yang

diubah suai atau dikenali sebagai tanah liat bersaiz nano iaitu Cloisite B30

(montmorilonit yang diubah suai dengan garam ammonium) telah digunakan dalam

penyelidikan ini. Nanokomposit PLA telah dihasilkan dengan menggunakan teknik

interkalasi cairan. Analisis morfologi, haba dan ujian mekanikal telah dijalankan bagi

kedua-dua PLA asli dan juga PLA yang telah dicampurkan dengan tanah liat bersaiz

nano. Analisis morfologi telah dijalankan dengan menggunakan Pembelauan Sinar X

(XRD) dan Mikroskop Imbasan Elektron (SEM). Kestabilan haba nanokomposit telah

dikaji dengan menggunakan Analisis Thermogravimetri (TGA). Data suhu transisi kaca,

Tg telah direkodkan dan dianalisis menggunakan Imbasan Perbezaan Kalorimeter

(DSC). Selain daripada itu, ciri-ciri mekanikal yang terdapat pada nanokomposit

tersebut juga telah dikaji melalui ujian tegangan. Berdasarkan kajian yang telah

dijalankan, eksfoliasi silikat berlapis Cloisite B30 di dalam matriks PLA mungkin

terjadi kerana tiada puncak yang ketara dapat diperhatikan daripada data yang

diperolehi dari XRD. Imej SEM pula tidak dapat menentukan penyebaran bagi tanah liat

bersaiz nano tetapi dapat membuktikan bahawa sampel nanokomposit mempunyai

gumpalan besar yang menjadi pusat tumpuan tekanan. Dalam analisis haba, TGA

mencatatkan penurunan kestabilan haba nanokomposit sejajar dengan peningkatan

kandungan Cloisite B30 yang di tambah ke dalam matriks PLA. Tg bagi nanokomposit

PLA juga tidak menunjukkan peningkatan jika dibandingkan dengan PLA asli. Analisis

mekanikal untuk kesemua sampel telah dijalankan dengan menggunakan Mesin Ujian

Universal. Tekanan maksima dan kekuatan maksima bagi nanokomposit telah

merekodkan keputusan yang rendah tetapi menunjukkan ciri keelastikan yang lebih

tinggi berbanding dengan PLA asli.

vii

TABLE OF CONTENTS

Page

SUPERVISOR’S DECLARATION ii

STUDENT’S DECLARATION iii

ACKNOWLEDGEMENTS iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENTS vii

LIST OF TABLES x

LIST OF FIGURES xiii

LIST OFSYMBOLS xv

LIST OFABBREVIATIONS xvi

CHAPTER 1 INTRODUCTION 1

1.1 Background of Research 1

1.2 Problem Statement 3

1.3 Research Objective 3

1.4 Scope of Research 4

1.5 Significance of Research 4

CHAPTER 2 LITERATURE REVIEW

2.1 Introduction 6

2.2 Polymer Nanocomposite 6

2.3 Types of Nanocomposite 9

2.3.1 Exfoliated Nanocomposites 9

2.4 Nanoclay 11

2.5 Polylactic Acid (PLA) 15

viii

2.5.1 Polylactic acid (PLA) nanocomposite 17

2.6 Preparation Method of Polymer Nanocomposites 18

2.6.1 In-Situ Polymertization 18

2.6.2 Solution Dispersion 19

2.6.3 Melt Intercalation 19

2.7 Characterization 21

2.7.1 Morphological studies 21

2.7.1.1 X-Ray Diffraction (XRD) Analysis 21

2.7.1.2 Scanning Electron Microscopy (SEM) 23

2.7.1.3 Transmission Electron Microscopy (TEM) 24

2.7.2 Thermal Analysis 26

2.7.2.1 Differential Scanning Calorimetry (DSC) 26

2.7.2.2 Thermogravimetric Analysis (TGA) 30

2.7.3 Mechanical testing 31

2.7.3.1 Tensile strength 31

2.7.3.2 Young’s modulus 31

2.8 Conclusion 34

CHAPTER 3 RESEARCH METHODOLOGY

3.1 Introduction 35

3.2 Materials 35

3.3 Preparation of PLA and PLA Nanocomposites 35

3.4 Sample Characterization 40

3.4.1 Thermal analysis 40

3.4.1.1 Differential Scanning Calorimeter (DSC) 40

3.4.1.2 Thermogravimetric Analysis (TGA) 42

3.4.2 Morphological studies 43

3.4.2.1 X-ray Diffraction (XRD) analysis 43

3.4.2.2 Scanning Electron Microscopy (SEM) 44

3.5 Mechanical Analysis 47

3.5.1 Tensile Test 47

CHAPTER 4 RESULT AND DISCUSSION 50

4.1 Introduction 50

4.2 Morphological Analysis 50

4.2.1 X-ray Diffraction (XRD) analysis 51

4.2.2 Scanning Electron Microscopy (SEM) 54

4.3 Thermal Anlaysis 57

4.3.1 Thermogravimetric Analysis (TGA) 57

ix

4.3.2 Differential Scanning Calorimetric (DSC) 58

4.4 Mechanical Analysis 61

4.4.1 Tensile strength test 61

4.5 Conclusion 65

CHAPTER 5 CONCLUSION AND RECOMMENDATION

5.1 Introduction 67

5.2 Conclusion 67

5.3 Recommendations for Future Research 68

REFERENCES 69

APPENDICES 73

A Methodhology 73

B Tensile test result 78

x

LIST OF TABLES

Table No. Title Page

2.1 Example of nanocomposites commercial utility 8

2.2 Characteristics of clay 12

2.3 Properties of Cloisite C20 13

2.4 Properties of Cloisite B30 14

2.5 Properties and characteristics of PLA 17

2.6 d-Spacing information for the nanoclays 22

2.7 Glass transition changes with nanofiller 27

2.8 DSC result for PLA and PLA LLDPE 28

2.9 Tg values of various PLA/B30 nanocomposites 29

2.10 Summary of the mechanical test result of PLA, PLA/PEG, and

their nanocomposites 33

3.1 Materials designation and composition 36

3.2 Temperature profile for extruder machine 36

3.3 Temperature profile for injection molding machine 37

3.4 Injection molding machine time setting 38

4.1 Effect of clay loading on glass transition temperature 59

4.2 Summary of tensile testing results with respect to pristine PLA

samples 62

4.3 Change in elastic modulus 65

6.1 Tensile strength test result for pure PLA 79

6.2 Tensile strength test result for 99.5% PLA/0.5% Cloisite B30

81

xi

6.3 Tensile strength test result for 99.0% PLA/1.0% Cloisite B30 83

6.4 Tensile strength test result for 98.0% PLA/2.0% Cloisite B 85

6.5 Mechanical test results of PLA, PLA/PEG, and their

nanocomposites 87

6.6 Actual and corrected value of max stress for PLA and PLA

nanocomposites 88

xii

LIST OF FIGURES

Figure No. Title Page

1.1 Classification of the biodegradable polymers 2

2.1 Schematic of the (A) intercalated, (B) exfoliated structure and

(C) phase separated of polymer nanoclay composite

morphology

9

2.2 Mechanism of organoclay and exfoliation during melt

processing 10

2.3 Structure of montmorillonite 11

2.4 Illustration of different states of dispersion of organoclay in

polymers with corresponding WAXS and TEM result 15

2.5 Schematic of nanocomposite synthesis by in-situ

polymerization 19

2.6 Melt intercalation approach 20

2.7 XRD diffractograms of OMMT, PLA, PLA/OMMT and PLA/

OMMT/EPMgMA5 23

2.8 SEM micrograph of fillers (SF, MSF and WF) 24

2.9 Change of TEM images with the different contents of

ZnAL(DS) in the PS/LDH nanocomposites sample: (a) 5 wt%,

(b) 10 wt%, and (c) 20 wt%. The inset in (c) shows the enlarge

image of the part marked by rectangle

25

2.10 DSC thermograms for PLA with 0%, 1%, 2%, 3%, 4%, and 5%

(w/w) of Cloisite B30 29

2.11 TGA curves of PLA and PLA nanocomposites 30

2.12 Tensile strength and modulus for MA compatibilized PE organo

MMT nanocomposites 32

2.13 Stress strain curves for PLA, PEG/PLA, and their

nanocomposites 33

xiii

3.1 EUROLAB 16 Twin Screw Extruder 37

3.2 NISSEI Injection Molding Machine NS20 38

3.3 Scheme of PLA nanocomposites samples preparation 39

3.4 TGA/DSC STARe System (Mettler Toledo) 40

3.5 Scheme of thermal characterization method using DSC 41

3.6 Scheme of thermal characterization method using TGA 42

3.7 XRD Miniflex (Rigaku) 43

3.8 Scheme of characterization method using XRD 44

3.9 SEM EVO 50 series (Carl Zeiss) 45

3.10 Scheme of characterization method using SEM 46

3.11 Shimadzu AG-X Universal Testing Machine 47

3.12 Scheme of mechanical testing method 48

3.13 Scheme of overall research methodology 49

4.1 XRD pattern for pristine PLA 52

4.2 XRD pattern for 99.5% PLA/0.5% Cloisite B30 52



4.5 Fracture surface of Pristine PLA (a) at 100x magnification (b)

at 2500x magnification 55

4.6 Fracture surface of 99.5% PLA/0.5% Cloisite B30 (a) at 100x

magnification (b) at 2500x magnification 55





4.9 TGA profiles for pure PLA and PLA nanocomposites at

different loading of Cloisite B30 58

xiv

4.10 DSC thermograms of neat PLA 59

4.11 DSC thermograms of 99.5% PLA/0.5% Cloisite B30 60



4.14 Ultimate strain results from tensile testing 63

4.15 Ultimate stress results from tensile testing 64

4.16 Elastic modulus results from tensile testing 65

6.1 Drying and mixing process of PLA pellets 74

6.2 Extrusion and pelletizing process of PLA nanocomposites 75

6.3 PLA nanocomposite processing method using injection molding

machine 76

6.4 Scanning Electron Microscopy (SEM) method 77

6.5 Tensile testing method 78

6.6 Graph of stress versus strain for pure PLA 80

6.7 Graph of stress versus strain for 99.5% PLA/0.5% Cloisite B30 82



xv

LIST OF SYMBOLS

cal Caloric

cm Centimeter

Tc Crystallization temperature

°C Degree celcius

Tg Glass transition temperature

Tm Melting temperature

J Joule

nm Nanometer

s Second

wt% Weight percent

c Degree of crystallinity

Theta

xvi

LIST OF ABBREVIATIONS

Al Aluminum

ASTM American Society for Testing and Materials

CEC Cation exchange capacity

CNT Carbon nanotube

DSC Differential Scanning Calorimeter

EPMgMA Maleic anhydeide-grafed ethylene propylene rubber

LDH Layered double hydroxide

LLDPE Linear low density polyethylene

MSF Modified soy flour

MWCNT Multi-wall carbon nanotube

OMMT Organo-montmorillonite

PEG Polyethylene glycol

PLA Polylactic Acid

SEM Scanning Electron Microscopy

SF Soy flour

SWCNT Single-wall carbon nanotube

TEM Transmission electron microscopy

TGA Thermogravimetric Analysis

TPO Thermoplastic polyolefin

WD Wood floor

XRD X-ray Diffraction

CHAPTER ONE

INTRODUCTION

1.1. BACKGROUND OF RESEARCH

Polymer is a large molecule that is macromolecule which made up from

repeating structural units typically linked by covalent chemical bonds. The first polymer

used was natural products, especially cotton, starch, proteins, and wool. Polymer refers

to a large class of natural and synthetic materials with a wide variety of properties. The

wide application of polymer is in plastic industry. Due to the extraordinary range of

properties of polymeric materials, polymer plays an essential role in everyday life,

ranging from familiar synthetic plastics and elastomers to natural biopolymers such as

DNA and proteins.

Nanotechnology is now recognized as one of the most promising areas for

technological development currently. Nanotechnology can be defined as the science and

engineering in the design, synthesis, characterization, and application of materials and

devices where the smallest dimension of particles is on the nanometer scale or one

billionth of a meter (Kamel, 2007). In materials research, the development of polymer

nanocomposites is rapidly emerging as a research activity that could broaden the

applications of polymers for the benefit of many different industries. Polymer

nanocomposites are polymers which are thermoplastics, thermosets or elastomers that

have been reinforced with small quantities.

Nanoscale interactions have significant implications on the macroscopic

behaviour of materials as every structural level contributes to the mechanical stability

and durability of the resulting materials (Ciprari, 2004). It has become increasingly

2

important to understand and manipulate materials at the nanoscale to develop new

functional materials for engineering and other application. Nanostructured and

nanocomposite materials can show significant improvement of mechanical properties

(Khudyakov, David Zopf & Turro, 2009).

Polylactic acid (PLA) is a biodegradable polymer derived from a lactic acid. It is

a highly versatile material which made from 100% renewable resources such as corn,

sugar beet, wheat and other starch-right products. It exhibits many properties that are

comparable to or better than many petroleum based plastics that make PLA can be use

for various applications (Platt, 2006). PLA cannot be considered as a new biodegradable

polymer because as early as 1845, it was synthesized by Theophile-Jules Pelouze by the

condensation of lactic acid (Auras et. al., 2010). Figure 1.1 shows the classification of

biodegrable polymer.

Figure 1.1: Classification of the biodegradable polymers

Source: Averous and Boquillon (2004)

3

Polymer composite theory predicts that improved bonding between polymer and

matrix leads to improved mechanical properties. Despite these predictions, however,

mechanical testing of nanocomposites has shown mixed results.

Some experimental data

has shown that reduced particle size improves mechanical properties, specifically elastic

modulus.

Other studies have shown that elastic modulus decreases with reducing on

dimension (Ciprari, 2004).

In the past decade, extensive research has focused on polymer nanocomposites

in hopes of exploiting the unique properties of materials in the nano-sized particle.

A

general conclusion has been drawn that nanocomposites show much improved

mechanical properties over their micro-sized counterparts.

Because of their small size,

nanoparticles have a high surface to volume ratio and provide high energy surfaces

(Winey, 2006). An expected result of embedding nanoparticles into a polymer matrix is

enhanced bonding between the polymer matrix and filler, resulting from the

nanoparticles’ high interfacial energy (Li et. al., 2010).

1.2 PROBLEM STATEMENT

PLA composite (microcomposite) is traditionally used in industries but it offers low

strength and low thermal stability of material. Therefore, PLA nanocomposite is

introduced because it shows improvement in those properties.

1.3 RESEARCH OBJECTIVE

1.3.1 To investigate the thermal properties of PLA nanocomposite that is incorporated

with modified nanoclay.

4

1.4 SCOPE OF RESEARCH

This research is focusing on PLA nanocomposites which is biodegradable

aliphatic polyester that can be synthesize from renewable resources. The scopes of this

research are as follow:

1.4.1 Cloisite B30 is type of nanoclay known as montmorillonite modified with a

quaternary ammonium salt was used as nanofiller in this research that is to be

incorporated with pristine PLA. Nanoclay is chosen as the nanofiller because it

is easy to acquire from suppliers and the price is low compared to other

nanofiller such as carbon nanotube (CNT).

1.4.2 Melt intercalation method is implemented to prepare PLA nanocomposite as it is

widely use in industrial application.

1.4.3 Characterization of PLA nanocomposite consists of morphological and thermal

analysis. The morphological analysis was done using X-Ray Diffraction (XRD)

and Scanning Electron Microscopy (SEM). In addition, Differential Scanning

Calorimeter (DSC) and Thermogravimetric Analysis (TGA) have been utilized

in order to observe the thermal behaviour of PLA nanocomposites.

1.4.4 The mechanical properties of the nanocomposites was obtained from tensile test

result.

1.5 SIGNIFICANCE OF RESEARCH

This research discussed about virgin PLA that was incorporated with Cloisite

B30 forming PLA nanocomposite as the key of modification. Polymer nanocomposites

consisting of a polymer matrix with nanoparticle filler, have been predicted to be one of

the most beneficial applications of nanotechnology. Nanoparticles provide better

thermal and mechanical properties compared to microparticle. PLA nanocomposite is

one of the most promising biodegradable polymer as it can be produce from 100%

renewable resources. It is relatively cheap and has some remarkable properties that it

5

suitable for different applications. Besides, PLA has been intensively studied and used

for biomedical material as it can be degraded in human body. The use of PLA has been

further extended for food packaging applications because of its high film and packaging

performance characteristics. Currently, PLA is used for containers for bottled water

packaging, bottled juices, sandwich containers, and yogurts (Ahmed, Varhney, & Auras,

2010).

CHAPTER TWO

LITERATURE REVIEW

2.1 INTRODUCTION

Nanotechnology is one of the most popular fields for research and development

currently. The term ‘nanotechnology’ is only specifically referred recently although

nanotechnology involve nanoscale dimension has been discovered decades ago.

Nanoscale interactions have profound implications on the macroscopic behaviour of

materials as every structural level contributes to the mechanical stability and durability

of the resulting materials (Devaprakasam et. al., 2007). In nanocomposite field with the

critical scale below 100nm, there are many diverse topics which consist of composite

reinforcement, barrier properties, flame resistance, electro-optical properties, cosmetic

applications, bactericidal properties. This review will focus on polymer nanocomposite,

types of nanocomposites, PLA composite, PLA nanocomposite and a characterization

method of nanocomposite.

2.2 POLYMER NANOCOMPOSITE

A polymer composite is a combination of a polymer matrix and a strong

reinforcing phase, or filler. Polymer composites provide desirable properties unavailable

in matrix or filler materials alone. A polymer nanocomposite is a polymer matrix with a

reinforcing phase containing one dimensional nano-sized particle. Nanocomposites are

polymers with particle-filled which at least one dimension of the dispersed particle is in

nanometer scale (Kashiwagi et. al., 2004). The polymer nanocomposites also defined as

polymer matrix containing nanostructures of inorganic nature (Fréchette & Reed, 2007).

7

In order to enhance the performance of polymer especially rubber, fillers of

polymers is introduced. According to Ciprari’s studies, 2004 nanocomposites showed

improvements in mechanical properties over their micro-sized similar systems. It is due

to nanoparticles have a high surface to volume ratio and provide high energy surfaces.

Polymer composite theory suggests that improved bonding between polymer and matrix

leads to improved mechanical properties.

Besides that, increase of polymer toughness (J/m3) always considered as an

improvement or enhancement of polymer nanocomposites properties (Kudyakov et al.,

2009). In addition, polymers with nanoscale additive showed an improvement in

flammability properties because one weak aspect of polymer is that they are

combustible under certain conditions but nanocomposites provide a possible alternative

to conventional flame retardants (Kashiwagi et. al., 2004).

Devaprakasam et. al., studies state that nanoparticles with uniform packing

density in the polymer matrix results in homogeneous mechanical properties compared

to microcomposite which results in heterogeneous mechanical properties. It is due to

high energy dissipation and big particles with weak interfacial bonding of

microcomposite. The clay-based nanocomposites always obey continuum mechanics

predictions where they can exhibit properties not expected with larger scale particulate

reinforcemens (Paul & Robeson, 2008). The wear resistance of the nanocomposite is

enhanced as the strong interfacial bonding between the nanoparticles and matrix due to

high specific area of nanoparticle. Thus, it offers better nanotribo-mechanical

performance compared to that of the microcomposite (Devprakasan et. al., 2007).

8

Table 2.1 Example of nanocomposites commercial utility

Polymer Matrix Nanoparticle Property

improvement Application

Polyamide 6 Exfoliated clay Stiffness Timing belt cover

for automotive

Thermoplastic

polyolefin (TPO) Exfoliated clay

Stiffness and

strength

Exterior step

assist

Epoxy Carbon nanotubes Stiffness and

strength Tennis rackets

Epoxy Carbon nanotubes Stiffness and

strength Hockey sticks

Polyisobutylene Exfoliated clay Permeability barrier Tennis balls, tires

and soccer balls

SBR, natural rubber

and polybutadiene

Carbon black

(20-100 nm:

primary particles)

Strength and wear Tire

Various MWCNT Electrical

conductivity

Electrostatic

dissipation

Unknown Silver Antimicrobial Wound care and

bandage

Nylon MXD6, PP Exfoliated clay Barrier

Beverage

containers and

film

SBR rubber Not disclosed

Improved tire

performance in

winter

Winter tires

Natural rubber Silver Antimicrobial Latex gloves

Various Silica Viscosity control and

thixotropic agent Various

Polyamides nylon 6,

66, 12 Exfoliated clay Barrier Auto fuel system

Source: Paul and Robesson, (2008)

9

2.3 TYPES OF NANOCOMPOSITE

Nanoparticles are classified in three different natures. The types of

nanocomposite comprising of intercalated clay, exfoliated clay and phase separated

polymer-nanocomposite. From the three nanocomposites, exfoliated clay is the most

desired one. The three main types of nanocomposite are schematically presented in

Figure 2.1.

Figure 2.1: Schematic of the (A) intercalated, (B) exfoliated structure and (C) phase

separated of polymer nanoclay composite morphology

Source: Bhat. et. al. (2008)

2.3.1 Exfoliated Nanocomposites

Exfoliation is a measure of how separated the nanoclay platelets are (Snyder,

2007). Complete exfoliation that is separation of platelets from one another and

dispersed individually in the polymer matrix is the desired goal of formation for many

10

purposes. Paul and Robesson studies have suggested alternative ideas about how the

details of the mixing equipments and conditions change the state of the dispersion

achieved. The ideas are summarized in the figure below:

Figure 2.2: Mechanism of organoclay and exfoliation during melt processing

Source: Paul and Robeson (2008)

Comparing to the pristine polymer or polymer with smectic clay, exfoliated

nanocomposite with high aspect ratio demonstrates enhance properties and in most

cases (Kudyakov et. al., 2009). Based on modification of polymeric systems, exfoliated

clays could result in significant mechanical property advantages (Gacitua, Ballerini &

Zhang, 2005). In intercalated nanocomposites, the unit cells of clay structure are

expended by the insertion of polymer into the interlayer spacing while the periodicity of

the clay structure is maintained. However, the crystal structure of the clay for exfoliated

nanocomposite is completely exfoliated by individual dispersion of the clay layers into

the polymer matrix (Yusoh, Jin & Song, 2010). The difference in the micro-phase

morphology of these two types is the reason in the difference of their physical properties

(Xia, Shaw & Song, 2005). There is a number of ways to increase a degree of

11

exfoliation in a nanocomposite, such as in situ polymerization, melt blending, solution

blending, sonication, high shear mixing, melt intercalation (Kudyakov et al., 2009).

2.4 NANOCLAY

Montmorillonite or also known as clay consist of platelets with an inner

octahedral layer sandwiched between two silicate tetrahedral layers as illustrated in

Figure 2.3. It is the most widely used clay to prepare polymer nanocomposites. The

dioctahedral 2:1 phyllosilicate consists of silica tetrahedrons having oxygen and

hydroxyl ions tetrahedrally arranged around Si atom. The base of the tetrahedrons is

made up of oxygen atoms while the hydroxyl group makes up the tip of the tetrahedron

and is fused with the aluminum octahedron (Alian, 2008).

Figure 2.3: Structure of montmorillonite

Source: Galgali (2003)

12

Filler in the nanoscale is known as nanoclay. A valuable nanocomposite is one

with the largest possible surface of nanofiller. In fact, it means avoiding aggregation of

nanoparticles but exfoliation of nanoclays is the most desired type of nanocomposite

(Kudyakov et. al., 2009). Nanoclay is a type of filler which is one of the most affordable

materials in industry. It is made of montmorillonite mineral deposits that known to have

platelets structure with average dimension of 1 nm thick and 70 to 150 nm wide (Bhat,

Hegde, Kamath, & Deshpande, 2008). A measure of how thoroughly mixed a clay with

a resin is called dispersion.

A technique that is used to analyze the dispersion is by examining the location

where there is no nanoclay present as to determine whether the clay is evenly distributed

among the resin. However, exfoliation is a measure of how separate nanoclay platelets

are. The analysis technique of exfoliation is an attempt to determine the average spacing

between platelets. The analysis is also to quantify the number of platelets in each

particle. While there is currently no single system that can describe both the levels of

exfoliation and dispersion of the nanoclays with complete certainty, X-ray Diffraction

(XRD) coupled with Transmission Electron Microscopy (TEM) microscope analysis is

the most reliable and is currently the most often used to examine clay containing

nanocomposites (Ryan, 2007).

Table 2.2: Characteristics of clay

Source: Fukushima, Tabuani, and Camino (2008)

abstract - umpir.ump.edu.myumpir.ump.edu.my/5122/1/cd6482.pdf · analisis morfologi, haba dan ujian...

Documents