EFFECT OF PHYSICAL AND MECHANICAL PROPERTIES OF PU

BIOPOLYMER MEMBRANES UPON USE OF DIFFERENT FABRICATION

TECHNIQUES

RAHIMAH BINTI ABD RAHIM

A thesis is submitted in partial

fulfillment of the requirement for the award of the

Degree of Master of Mechanical Engineering

Faculty of Mechanical and Manufacturing Engineering

University Tun Hussein Onn Malaysia

SEPTEMBER 2013

v

Abstract

In developing polymer membranes that response to prevents liquid water from

penetrating through, while at the same time permitting moisture past out through,

polymer membrane with various structure ranging from dense to highly asymmetric

morphologies (0.01 - 0.25 mm) were fabricated through three different techniques;

blends, curing and grafting fabrication. From FT-IR analysis, BP/PEG (blends, curing

and grafting) were fully converted into solid polymer membrane with functional group of

N-H stretching in region 3350 - 3250 cm-1.

Morphological result of BP/PEG shows three

types of surface; open, close and blind surface with cylindrical blind and ink bottle

shaped structure randomly. Due to lower porosity of skin over a symmetric support acts

as a barrier, BP/PEG polymer membranes resultant no water permeability as compared to

BP/DMF, which exhibit extremely higher water permeability with value 0.161 L/s.m3 at

lower concentration. Water absorption analysis shows that mechanical properties of the

prepared membranes were significantly influenced by their structure and amount of water

absorbed. Thus, BP/PEG (blends, curing and grafting) preparation gave lower amount of

water absorption with less than 0.01% water absorption increment rather than BP/DMF

12% (w/v) with highly porosity value of 0.07%. Thermogravimetric analysis (TGA)

reviewed that the hard segment decomposition temperature was occur at 295 0C – 395

0C,

meanwhile for soft segment at 370 0C – 500

0C. Based upon modulus, tensile, strain and

tear strength also energy at break, evidently shows that the BP/PEG (grafting) method

gave the best performance on physical and mechanical properties with highest mean

value of 12419 N/mm, 14.11 MPa, 38.289 %, 50.67 N/mm and 21.627 N respectively.

Reciprocally, PEG solvent does significantly increase the mechanical properties with the

reaction of BP rather than DMF solvent with varieties of concentration. Moreover,

BP/PEG membrane from each fabrication technique had obvious dense porous structural

feature with open, close and blind pores in practically boundless development as of

adequate final use in membrane application.

vi

Abstrak

Dalam membangunkan polimer membran yang menghalang tindak balas cecair

daripada meresap dan pada masa yang sama membenarkan kelembapan melaluinya,

polimer membran dengan pelbagai struktur, terdiri daripada morfologi yang padat

sehingga simetri yang tertinggi ( 0.01 - 0.25 mm) telah dihasilkan melalui tiga teknik

berbeza; campuran (blends), ikatan (curing) dan cantuman (grafting). Daripada

analisis FT-IR, BP/PEG (campuran ,ikatan dan cantuman) telah ditukar sepenuhnya

kepada polimer membran dengan kumpulan berfungsi NH regangan dalam rantau

3350-3250 cm-1. Hasil morfologi, BP/PEG menunjukkan tiga jenis permukaan;

terbuka, rapat dan buta dengan struktur silinder buta dan botol dakwat. Disebabkan

oleh keliangan permukaan, sokongan simetri bertindak sebagai penghalang, BP/PEG

polimer membran yang dihasilkan, tidak kebolehtelapan air berbanding BP/DMF,

yang mempamerkan kebolehtelapan air yang sangat tinggi dengan nilai 0.161 L/s.m3

pada kepekatan yang lebih rendah. Analisis penyerapan air menunjukkan, sifat-sifat

mekanikal membran ketara dipengaruhi oleh struktur dan jumlah air yang menyerap.

Oleh itu, BP/PEG (campuran, ikatan dan cantuman) memberikan jumlah yang lebih

rendah iaitu kurang 0.01 % air kenaikan penyerapan, berbanding BP/DMF 12%

(w/v) dengan keliangan tertinggi iaitu 0.07 %. Termogravimetri analisis ( TGA )

mengkaji bahawa segmen keras suhu penguraian berlaku pada 295 0C - 395

0C ,

sementara bagi segmen lembut pada 370 0

C - 500 0C. Berdasarkan modulus,

tegangan, tekanan dan kekuatan tenaga berhenti, jelas menunjukkan bahawa kaedah

BP/PEG (cantuman) menunjukkan persediaan yang terbaik pada sifat-sifat fizikal

dan mekanikal dengan nilai min tertinggi 12419 N / mm, 14.11 MPa, 38,289 %,

50.67 N /mm dan 21,627 N setiapnya. Pelarut PEG ketara meningkatkan sifat

mekanik dengan tindakbalas BP berbanding pelarut DMF. Selain itu, BP/PEG

membran dari setiap teknik fabrikasi mempunyai ciri-ciri yang struktur jelas tebal

berliang dengan liang terbuka, berhampiran dan buta dalam pembangunan praktikal

terbatas pada penggunaan akhir yang mencukupi dalam aplikasi membran.

vii

TABLE OF CONTENTS

TITLE i

DECLARATION ii

DEDICATION iii

ACKNOWLEGDEMENT iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENTS vii

LIST OF TABLES x

LIST OF FIGURES xi

LIST OF SYMBOLS xvi

CHAPTER 1: INTRODUCTION 1

1.1 Research Background 1

1.2 Problem Statement 2

1.3 Research Aim 3

1.4 Scopes of Study 3

1.5 Objectives of Study 4

CHAPTER 2: LITERATURE REVIEW 5

2.1 Background of Membranes 5

2.2 Membranes Classification 6

2.2.1 Isotropic Membranes 7

2.2.2 Anistropic Membranes 10

2.2.3 Porosity 11

viii

2.3 Typical Membrane Technique Preparation 13

2.4 Membrane Modification 17

2.5 Material for the Development of Polymer Membrane 35

CHAPTER 3: METHODOLOGY 44

3.1 Flow Chart of Methodology 45

3.2 Preparation of Bio-monomer 46

3.3 Overview of Fabrication Method of Biopolymer (BP) Membrane 46

3.4 Characterization of Membranes 54

3.4.1 Structure by means via Infra-red Spectroscopy (FTIR) 54

3.4.2 Scanning Electron Microscope (SEM) 55

3.4.3 Water Permeability 56

3.4.4 Water Absorption 56

3.4.5 Thermogravimetric Analysis (TGA) 57

3.4.6 Mechanical Properties of Polymeric Membrane for Tensile

and Tear Strength 59

3.4.6.1 Tensile Strength 59

3.4.6.2 Tear Strength 60

CHAPTER 4: RESULT AND ANALYSIS 62

4.1 Chemical Reaction of Biopolymer (BP) 63

4.2 Functional Group Determination by means of Infrared 66

spectroscopic (FT-IR) for BP/PEG (blends) - 1 ply,

BP/PEG (curing) - 2 plies and BP/PEG (grafting) - 1 ply

4.2.1 Bio-monomer (VOM), Biopolymer (BP) and PEG 66

4.2.2 BP/PEG (blends) - 1 ply 71

4.2.3 BP/PEG (curing) - 2 plies 74

4.2.4 BP/PEG (grafting) - 1 ply 77

4.2.5 BP/DMF 80

4.2 Morphological Changes of Polymer Membrane by 84

Scanning Electron Microscope (SEM).

4.3 Water Permeability 88

ix

4.4 Water Absorption 90

4.5 Thermal Gravimetric Analysis (TGA) Measurements 94

4.6.1 Weight Loss Kinetics of BP/PEG (blends) - 1ply,

BP/PEG (curing) - 2 plies, BP/PEG (grafting) - 1 ply

and Commercial Synthetic Membrane

4.6 Mechanical Properties via Tensile and Tear Strength 97

CHAPTER 5: CONCLUSIONS AND RECOMMENDATIONS 99

5.1 Conclusions 99

5.2 Recommendations 101

REFERENCES 102-114

APPENDIXES 115-122

VITA

x

LIST OF TABLES

Table 3.1 Ratio of bio-monomer to 4, 4’- methylen-bis-(phenylisocyanate),

MDI; (wt/wt)

Table 3.2 Ratio of PEG2000 to HMDI; (wt/wt)

Table 3.3 Ratio of bio-monomer to 4, 4’- methylen-bis-(phenylisocyanate),

MDI; (wt/wt)

Table 3.4 Ratio of PEG2000 to HMDI ; (wt/wt)

Table 3.5 Ratio of bio-monomer to 4, 4’- methylen-bis-(phenylisocyanate),

MDI; (wt/wt)

Table 3.6 Different concentration of N,N- dimethyl-formamide (DMF) solvent

used

Table 3.7 Basic wavenumbers of peaks used for FTIR analysis and

corresponding functional groups.

Table 4.1 Range of pore sizes for different surfaces

Table 4.2 Range of pore sizes for different surfaces

Table 4.3 Water permeability of BP/PEG and BP/DMF polymer membranes

Table 4.4 Water absorption increment of BP/PEG and BP/DMF polymer

membranes

Table 4.5 Decomposition temperature for BP/PEG polymer and synthetic

commercial membranes

Table 4.6 TGA parameter of BP/PEG and BP/DMF polymer membranes

Table 4.7 Ratio of monomer to MDI as compared to the ratio of derivative

weight loss of soft to hard segment after thermal decomposition

Table 4.8 Mechanical properties of BP/PEG and BP/DMF polymer membranes

Table 4.9 Tear strength of BP/PEG and BP/DMF polymer membranes

xi

LIST OF FIGURES

Figure 2.1 Membrane classification

Figure 2.2 Membrane classification according to the morphology

Figure 2.3 Schematic diagram of different membrane morphologies of isotropic

membrane

Figure 2.4 Schematic diagram of different membrane morphologies

Figure 2.5 Schematic diagram of different membrane morphologies of

anisotropic membrane

Figure 2.6 Closed, blind and through pores in materials

Figure 2.7 Different types of pores

Figure 2.8 SEM images of membranes prepared by phase inversion method with

different thickness and drying time

Figure 2.9 Schematic representation of the methods of polymer modification

Figure 2.10 SEM images that showed the effect of blending of chitosan with PEG

on membrane surface morphology

Figure 2.11 Morphology of PVDF/PEO-b-PMMA polymer membranes

Figure 2.12 Surface morphologies of PBLG/PAA modification bend films

Figure 2.13 Relationship between the tensile strength of PBLG/PAA blend films

and PAA mole contents

Figure 2.14 Micrograph of membranes based on ionomer/additive. (A) Cross-

sections; (B) surfaces; (1) matrix polymer neat ionomer; (2) matrix

polymer ionomer/additive 80:20 by weight; (3) matrix polymer

ionomer/additive 70:30 by weight

Figure 2.15 ATR–FT-IR spectra of PU membrane surfaces before and after each

step of modification (PU control, PU/HMDI, and PU/PEG)

Figure 2.16 SEM micrographs for the control and modified polyurethane

membranes. (a) and (d); control membranes, (b) and (e); treated

xii

with HMDI, (c) and (f); treated with PEG at the molecular weight of

1500

Figure 2.17 ATR-FTIR spectra for the control PU, PU-MDI and PU-BPEG

modified surfaces

Figure 2.18 Production (million tonnes and %) of nine major vegetable oils in

2011/12 (Sources: USDA February 2013 of vegetable oils)

Figure 2.19 Fatty acids as starting materials for the synthesis of novel fatty

compounds: (1) oleic acid, (2) linoleic acid, (3) linolenic acid, (4)

petroselinic acid, (5) erucic acid, (6) calendic acid, (7) α-eleostearic

acid, (8) vernolic acid, (9) ricinoelic acid

Figure 2.20 Hard segment and soft segments of polyurethane elastomer

Figure 2.21 Virtually crosslinked of polyurethane elastomer

Figure 2.22 TGA thermograms of soybean oil polyol based PU foam vs. PPO-

based foam in N2

Figure 2.23 Structural of Methylene diphenyl diisocyanate (MDI) and Toluene

(TDI)

Figure 2.24 Methylene diphenyl diisocyanate (MDI)

Figure 2.25 Structural of Toluene diisocyanate (TDI)

Figure 2.26 Hexamethylene Diisocyanate (HMDI)

Figure 2.27 Structural of Polyethylene glycol (PEG)

Figure 2.28 Structural of dimethylformamide (DMF)

Figure 3.1: Methodology flow chart

Figure 3.2: Bio-monomer (VOM)

Figure 3.3: Simplified view of BP/PEG (blends) - 1 ply membrane preparation

Figure 3.4: Simplified view of BP/PEG (curing) – 2 plies membrane preparation

Figure 3.5: Simplified view of BP/PEG (grafting) membrane preparation

Figure 3.6: Simplified view of BP/DMF membrane preparation

Figure 3.7: Fourier Transform Infrared Spctroscopy (FTIR)

Figure 3.8: Scanning Electron Microscope (SEM)

Figure 3.9: Water permeability test equipment

Figure 3.10 Water absorption of membranes

Figure 3.11 TGA profile with derivative weight loss of membrane

Figure 3.12 Schematic illustration of tensile test for polymer membrane according

to ASTM D882 Tensile Strength Properties

xiii

Figure 3.13 Positioning of polymer membrane sample placed between the two

vertical rubber grips of the tester during the test

Figure 3.14 Universal Testing Machine (UTM)

Figure 3.15 Schematic illustration of tear test for polymer membrane according to

ASTM D1922 Tear Strength Properties

Figure 3.16 Positioning of polymer membrane sample between two vertical rubber

grips of the tester during the test

Figure 4.1 Preparation of BP with cross linking agent MDI

Figure 4.2 Second solution of HMDI with PEG (PEG layer)

Figure 4.3 Expected structure of the biopolymer (BP) and polyethylene glycol

(PEG 2000) based on grafting technique

Figure 4.4 FTIR spectra at region 4000-600 cm-1

of Virgin Oil Monomer (VOM)

Figure 4.5 FTIR spectra at region 4000-600 cm-1

of Biopolymer (BP)

Figure 4.6 Overlay FTIR spectra at region 4000-600 cm-1

of Virgin Oil Monomer

(VOM) and Biopolymer (BP)

Figure 4.7 FTIR spectra at region 4000-600 cm-1

of PEG after reaction with

HMDI

Figure 4.8 FTIR overlay spectra at region 4000-600 cm-1

for BP and PEG

Figure 4.9 FTIR spectra at region 4000-600 cm-1

of BP/PEG (blends) - 1ply

Figure 4.10 FTIR overlay spectra at region 4000-600 cm-1

for BP and BP/PEG

(blends) – 1 ply

Figure 4.11 FTIR overlay spectra at region 4000-600 cm-1

for PEG and BP/PEG

(blends) – 1 ply

Figure 4.12 FTIR overlay spectra at region 4000-600 cm-1

for BP, PEG and

BP/PEG (blends) – 1 ply

Figure 4.13 FTIR spectra at region 4000-600 cm-1

for BP/PEG (curing) – 2 plies

Figure 4.14 FTIR overlay spectra at region 4000-600 cm-1

for BP and BP/PEG

(curing) – 2 plies

Figure 4.15 FTIR overlay spectra at region 4000-600 cm-1

for PEG and BP/PEG

(curing) - 2 plies

Figure 4.16 FTIR overlay spectra at region 4000-600 cm-1

for BP, PEG and

BP/PEG (curing) – 2 plies

Figure 4.17 FTIR spectra at region 4000-600 cm-1

for BP/PEG (grafting) – 1 ply

xiv

Figure 4.18 FTIR overlay spectra at region 4000-600 cm-1

for BP and BP/PEG

(grafting) - 1 ply

Figure 4.19 FTIR overlay spectra at region 4000-600 cm-1

for PEG and BP/PEG

(grafting) - 1 ply

Figure 4.20 FTIR overlay spectra at region 4000-600 cm-1

for BP, PEG and

BP/PEG (grafting) – 1 ply

Figure 4.21 FTIR spectra at region 4000-600 cm-1

for BP/DMF 12% (w/v)

Figure 4.22 FTIR spectra at region 4000-600 cm-1

for BP/DMF 15% (w/v)

Figure 4.23 FTIR spectra at region 4000-600 cm-1

for BP/DMF 18% (w/v)

Figure 4.24 FTIR overlay spectra at region 4000-600 cm-1

for three different

concentrations (DMF) 12%, 15% and 18% (w/v)

Figure 4.25 FTIR overlay spectra at region 4000-600 cm-1

for BP and BP/DMF

12% (w/v)

Figure 4.26: FTIR overlay spectra at region 4000-600 cm-1

for BP and BP/DMF

15% (w/v)

Figure 4.27 FTIR overlay spectra at region 4000-600 cm-1

for BP and

BP/DMF18% (w/v)

Figure 4.28 FTIR overlay spectra at region 4000-600 cm-1

for BP, and three

different concentrations (DMF) 12%, 15% and 18% (w/v)

Figure 4.29 SEM micrographs of polymer membranes illustrating the effects of

different solvent type on the porous structure and preparation method.

(a – g) (1) top surface, (a – g) (2) cross-section and (a – g) (3) bottom

surface.

Figure 4.30 Water permeability of the porous and nonporous polymer membranes

Figure 4.31 Water absorption increment of biopolymer; (___) BP, (___) BP/PEG

(curing) - 1ply, (___) BP/PEG (blends) - 2 plies, (___) BP/PEG

(grafting), (___) BP/DMF (12% w/v), (___) BP/DMF (15% w/v),

(___) BP/DMF (18% w/v)

Figure 4.32 TGA Thermogram and derivative weight loss of BP/PEG (blends)-1

ply membrane.

Figure 4.33 TGA Thermogram and derivative weight loss of BP/PEG (curing)-2

plies membrane.

Figure 4.34 TGA Thermogram and derivative weight loss of BP/PEG (grafting-1

ply membrane.

xv

Figure 4.35 TGA Thermogram and derivative weight loss of commercial

(synthetic membrane)

Figure 4.36 Tear strength of BP/PEG and BP/DMF polymer membranes

Figure 5.I Correlation summary among membrane structures and properties of

different fabrication techniques.

xvi

LIST OF SYMBOLS

MDI : 4,4’-Methylen-bis-(phenylisocynate)

PEG : Polyethylene glycol

HDMI : Hexamethylene Diisocyanate

DMF : N,N-dimethylformamide

SEM : Scanning Electron Microscope

UTM : Universal Testing Machine

FTIR : Fourier Transform Infrared

TGA : Thermogravimetric

PU : Polyurethane

ºC : Degree Celcius

1

CHAPTER 1

INTRODUCTION

1.1 Background of Research

Membrane and membrane processes are not a recent invention and it is a part of our

daily life. Membrane technology is now been industrially establish in impressively

large scale after a long period through the producing of biological membrane. As

reported [1], the key property is the ability of membranes to control the permeation

rate of water and liquid through the membranes. According to Baker et al. [2],

polymeric membranes have reached high growth and have gained an important place

in broad range of applications including in industrial sectors, gas separation,

wastewater treatment, food processing, medical devices and many others.

Due to the concern about global warming and the contribution of greenhouse

effect has increased dramatically; the use of renewable resource in the preparation of

various applications has been revitalized as studied [3]. Walpoth et al. [4] had been

studied that vegetable oil is one of the most valuable to develop as raw materials for

membrane. As reported [4], vegetable oil offer advantages such as low cost,

acceptable specific properties, biodegradability and availability of renewable

resources.

Medical devices are one of membrane applications which are fast growing

field that represents the largest consumption of membrane area per year as reported

[5]. In terms of total membrane produced, medical applications are at least equivalent

to all industrial membrane applications. By focusing to a very high cost of getting

medical devices in particular of dental bib for dental clinic use, proposed an ideas to

developing polymer membrane that respond to moisture/liquid content for use as a

protective clothing based on renewable resources (vegetable oil).

2

AnikaZafiah in her studied [6-7], plant oils and their derivatives have been

used by polymer chemists due to their renewable nature, world wide availability,

relatively low price, and their rich application possibilities, in which its main

constituent are triacylglycerols. Several arguments can be found to believe in the

great potential of plant oils as an alternative resource for the production of polymeric

materials as reported [7].

In the context of renewable, plant oils offer many advantages apart from its

renewability. Their world-wide availability and relatively low prices make them

industrially attractive and feasible, as daily demonstrated with industrial

oleochemistry. Furthermore, diverse chemistry can be applied on them, leading to a

large variety of monomers and polymers [8].

1.2 Problem Statement

Although, there are many techniques that have been used in polymer membrane

application, however it were not meet all the performance requirements for a

membrane dedicated to a particular application.

According to Sin et al. [9] through solvent casting techniques, it may yield

the following disadvantages such as skin of nonporous polymer of the surface, non-

homogeneous dispersion of pores, lack of inner connectivity of the pores and

remaining porogen within the scaffold after porogen leaching.

Other than that, through gas foaming, this technique resulting many pores are

closed with lack of pore inner connectivity as reported by Strathman et al. [10] .

Therefore membrane modifications are gaining rapidly increasing importance such as

blending, curing and grafting.

The volume of petroleum-based synthetic material such as plastic, appear as

wastes presents disposal authorities with an increasingly very serious problem and

becoming implication to the environmental problem as reported by Huayu et al. [11].

At one time it was relatively inexpensive to dispose of domestic and industrial waste

in holes in the ground.

Lucas et al. [12] in studied, reported that plant oils and their derivatives have

been used by polymer chemists due to their renewable nature, world wide

availability, relatively low price, and their rich application possibilities. Furthermore,

Nayak et al. [13] studied that by increasing demand of industrial raw materials to use

3

the renewable resources, vegetable oils were brought focus as a potential source of

raw materials. This is due to their potential to substitute petrochemical derivatives as

studied [13].

According to Gogolewski et al. [14], even polymeric membranes dominating

a very broad range due to its advantages, however membrane polymer also have their

limitations. This include, a very well-defined regular pore structure is difficult to

achieve. In addition, mechanical strength, thermal stability and the chemical

resistance are rather low for many organic polymers.

In contrast, some inorganic materials have disadvantages such as very brittle,

and due to complicated preparation methods and manufacturing technology, the

prices for many inorganic membranes are still very high.

1.3 Aim of Research

The key aim of this research is to early develop renewable biopolymer membranes

based on new functional group by means of FTIR, morphological structure by SEM,

water permeability, thermal stability by TGA, and mechanical properties (tensile and

tear strength) through the different membrane preparation technique (curing, blends

and grafting technique) with correlation of their membrane structure and property.

1.4 Scope of Research

This research focuses on developing renewable biopolymer membranes which based

on three different membrane preparation technique; curing, blends and grafting.

Polymer membranes with different range of pore (1 -100 µm) and thickness (0.01 -

0.25 mm) were prepared.

Chemical composition of the functional group was studied by using Fourier

Transform Infrared Spectroscopy (FTIR) while Scanning Electron Machine (SEM) is

to investigate the influences of the fabrication technique on membranes surface

morphological structure. Studies of thermal stability and mechanical properties were

observed by using Thermal gravimetric analysis (TGA), tensile and tear strength by

Universal Testing Machine (UTM) respectively. In addition, permeability was

determined by using water permeability, water absorption/water uptake analysis to

measure the amount of water through the pore of membranes.

4

1.5 Objectives of Research

i. To fabricate renewable polymer membrane via three different technique

preparation: BP/PEG (blends) - 1ply, BP/PEG (curing) – 2 plies and BP/PEG

(grafting) – 1 ply with PEG.

ii. To determine the best fabrication techniques based on the physical and

mechanical property functional group determination via FT-IR.

iii. To investigate the morphology, decomposition, water permeability, water

absorption and mechanical properties, physical and structure of polymer

membranes via Scanning Electron Machine (SEM), Thermogravimetric

Analysis (TGA), water permeation and Universal Testing Machine (UTM).

5

CHAPTER 2

LITERATURE REVIEW

2.1 Background of Membranes

A membrane is an interphase between two adjacent phases acting as a selective

barrier, regulating the transport of substances between the two components as studied

by Klempner et al. [15]. In general, membranes are thin layers, that can have

significantly different structures, but all have the common feature of selective

transport to different components in a feed. Mulder et al. [16] from his studied, state

that membranes are generally classified by the nature of the materials, selective

barrier, structure, membrane morphology, geometry, preparation method, separation

regime and process.

Membranes and membrane processes were first introduced as an analytical

tool in chemical and biomedical laboratories and then developed very rapidly into

industrial products with significant technical and commercial impact as reported

[16]. According to Gogolewski et al. [17], membranes are used on a large scale in

wide range of application areas such as to produce potable water from sea and

brackish water, to clean industrial effluents and recover valuable constituents, to

concentrate, purify, or fractionate macromolecular mixtures in the food and drug

industries, and to separate gases and vapors in petrochemical processes. It also plays

as key components in energy conversion and storage systems, in chemical reactors,

in artificial organs, and in drug delivery devices.

Lonsdale [18] in his studied, explain that membranes used in the various

applications differ widely in their structure, function and the way operated. However,

all membranes have several features in common that make them particularly

attractive tools for separation of molecular mixtures. Most important is that the

6

separation is performed by physical means at ambient temperature without

chemically altering the constituents of a mixture.

According to Drioli et al. [19], although synthetic membranes are widely

used as valuable scientific and technical tools in a modern industrialized society, they

are not very well defined in terms of their structure and function. The most

prominent association that many people have when thinking of a membrane

resembles that of a filter. However, a membrane can be much more complex in both

structure and function.

Bhattacharyya et al. [20] has summarized, the permeability of a membrane is

a measure of the rate at which a given component is transported through the

membrane under specific conditions of concentration, temperature, pressure, or

electric field. The study [21] shows, the transport rate of a component through

membrane is determined by the structure of the membrane, by a size of permeating

component, by the chemical nature and the electrical charge of the membrane

material and permeating components, and by the driving force such as concentration,

pressure or electrical potential gradient across the membrane.

Drioli et al. [22] studied, the use of different membrane structures and driving

forces has resulted in a number of rather different membrane processes such as

reverse osmosis, microfiltration, ultrafiltration, nanofiltration, dialysis,

electridialysis, Donnan dialysis, pervaporation, gas separation, membrane contactors,

membrane distillation, membrane based solvent extraction, membrane reactors and

others.

2.2 Membranes Classification

Membranes are grouped into polymeric and inorganic membranes. Membranes may

be homogeneous or heterogeneous, symmetrical or asymmetrical, and porous or non-

porous or with special chemical affinity dictated the mechanism of permeation and

separation. They also can be organic or inorganic, liquid or solid. The permeation

properties of polymer membranes are strongly influenced by both the preparative

route used and the final configuration (isotropic, asymmetric or composite) of the

membrane by studied [23]. The membrane classifications are shown in Figure 2.1.

7

Figure 2.1: Membrane classification [22]

From Zhang et al. [24] studied that in essence, a membrane is nothing more

than a discrete, thin interface that moderates the permeation of chemical species in

contact with it. This interface may be molecularly homogeneous, that is, completely

uniform in composition and structure, or it may be chemically or physically

heterogeneous. Figure 2.2 shows the schematic diagrams of the principal types of

membranes.

Figure 2.2: Membrane classification according to the morphology [24]

2.2.1 Isotropic Membranes

Isotropic microporous membranes have a rigid, interconnected pore, voided and

structure distributed randomly. The separation process is controlled by the pore size

distribution of microporous membranes and the hydrodynamic conditions. The

8

microporous membranes are prepared by phase separation, tracked etch, stretching,

or leaching. The phase separation is the most important method for the isotropic

microporous membrane preparation[25]. Figure 2.3 shows the schematic diagram of

different membrane morphologies.

(a) Dense membrane (b) Microporous

membrane

(c) Electrically charged

membrane

Figure 2.3: Schematic diagram of different membrane morphologies of isotropic

membrane [25]

As refer to Figure 2.3(a) of dense membrane morphology, studies from Krause et.al

[26] shows that dense membranes, also called “diffusion” membranes have no open

pores in the membrane wall or the outer skin of the wall. This membrane is rarely

used in practical membrane separation process because of its low flux caused by its

high membrane thickness, but the intrinsic properties of polymers will determine the

membrane performance and separation characteristics. Likewise, Marcano et al. [27],

explain that dense membranes are mainly used in laboratory to characterize the

intrinsic membrane properties for control release, gas separation, pervaporation,

nanofiltration, and reverse osmosis membranes for material screening. They are

prepared by solution casting and thermal melting extrusion approaches.

According to Klaaseen et al. [28], dense membranes consist of a dense film

through which permeate are transported by diffusion under the driving force of a

pressure, concentration, or electrical potential gradient. The separation of various

components of a mixture is related directly to their relative transport rate within the

membrane, which is determined by their diffusivity and solubility in the membrane

material. Thus, nonporous, dense membranes can be separate permeants of similar

size if their concentration in the membranes to perform the separation. Usually these

membranes have an anisotropic structure to improve flux. However, the advantage of

9

these membranes was their relatively high wall thickness due to mechanical

requirements.

Brieter et al. [29], from their studied explain that morphology of microporous

membrane is very similar in structure and function to a conventional filter as refer to

Figure 2.3(b). It has a rigid, highly voided structure with randomly distribute, and

interconnected pores. However, these pores differ from those in conventional filter

by being extremely small, on the order of 0.01 to 10 µm in diameter. All particles

larger than the largest pores are completely rejected by virtue of a sieving effect.

The sponge-like structure of this membrane is homogeneous and isotropic

with open surfaces on both wall sides. These membranes achieve reliable, adequate

performance and the mechanical stability in term of tensile strength and elongation at

break is combined with high reliability and handling safely during the manufacturing

process. Figure 2.4 below shows the types of microporous membrane structures.

Mulder [30] in his studied, explain that electrically charged membranes

morphology as refer to Figure 2.3(c) can be dense or microporous, but are most

commonly very finely microporous, with the pore walls carrying fixed positively

charged ions is referred to as an anion-exchange membrane because it binds anions

in the surrounding fluid. Similarly, a membrane containing fixed negatively charged

ions is called a cation-exchange membrane. Separation with charged membranes is

achieved mainly by exclusion of ions of the same charge as the fixed ions of the

membrane structure, and to a much lesser extent by the pore size. The separation is

affected by the charge and concentration of the ions in solution.

Symmetric Asymmetric Composite

Figure 2.4: Schematic diagram of different membrane morphologies [30]

10

2.2.2 Anisotropic Membranes

According to Koenhen et al. [31], anisotropic membranes are layer structures,

changing the porosity and pore size over the whole membrane wall. The anisotropic

membranes usually have a very thin surface layer supported on a thick microporous

substrate. The thin skin layer is the selective layer to perform separation, while the

microporous substrate mainly provides the mechanical strength. Because of the very

thin selective layer, the membrane fluxes are very high. Integrally asymmetric

membranes, composite membranes and supported liquid membranes are in the

category of anisotropic membranes

(a) Supported liquid

membrane

(b) Loeb-Sourirajan/

Assymetric membrane (c) Composite

Figure 2.5: Schematic diagram of different membrane morphologies of anisotropic

membrane [31]

In these recent years, interest in membranes formed from less conventional

materials has increased as reported [32]. Ceramic membranes, a special class of

microporous membranes, are being used in ultrafiltration and microfiltration

applications for which solvent resistance and thermal stability are required. Dense

metal membranes, particularly palladium membranes, are being considered for the

separation of hydrogen from gas mixtures, and supported liquid films as refer to

Figure 2.5 (a) are being developed for carrier-facilitated transport processes.

Meanwhile, the asymmetric membranes combine high permeant flow,

provided by a very thin selective top layer and a reasonable mechanical stability,

resulting from the under laying porous structure as refer to schematic diagram of

11

different membrane morphologies of anisotropic membrane in Figure 2.5(b).

According to Atala et al. [33], an asymmetric structure characterizes most of the

presently commercially available membranes, which are now produced from a wide

variety of polymers. By the most common method in generation of asymmetric

structures in membranes is the “phase-inversion” process.

Most of the presently available membranes are porous or consist of a dense

top layer on a porous structure. The preparation of membrane structures with

controlled pore size involves several techniques with relatively simple principles, but

which are quite tricky.

In Figure 2.5(c), a composite membrane is comprised of more than one

material and structure, and it also considered to belong to asymmetric membranes.

Such membranes are usually prepared by multistep method. The top and sub layer

can be originated from different polymeric materials with different structures, with

each layer able to be optimized independently. Usually, the top is a thin dense

polymer skin formed over a microporous support substrate. It can be achieved by

dip-coating, interfacial polymerization, in-situ polymerization or plasma

polymerization.

Tsui et. al [34] has summarized, usually the top layer is the active layer made

of high performance polymer that causes the separation of the solutes. This layer has

a thickness around 0.15 to 1 μm. This layer on its own has insufficient mechanical

strength and requires some support/reinforcement. As such, the desirable

reinforcement layer has to be porous material with desirable mechanical properties

and should not resist the passage of liquid. Compares with integrally asymmetric

membranes, composite membranes usually contain two separated layers with

different separation functions and different membrane materials. The porous

substrate acts as mechanical support and the skin layer is mainly used for the

selective purpose.

2.2.3 Porosity

According to Gupta et al. [35], filtration media in various forms including

membranes, woven, nonwoven and particulate beds are used extensively in a wide

variety of applications in areas such as biotech, health care, pharmaceutical, food and

beverage, power sources and chemical industries. The performance of filtration

12

media in all of these industries is determined by the pore structure characteristics of

the media.

Three kinds of pores are normally found in materials as in Figure 2.6. The closed

pores are not accessible while the blind pores terminate within the material. The

through pores permit fluid flow through the material and, hence, are the relevant

pores for this application. The important pore structure characteristics of filter media

are the most constricted through pore diameter, the largest pore diameter, the mean

pore diameter, pore shape, pore distribution, pore volume, pore volume distribution,

surface area, liquid permeability, gas permeability. Meanwhile influence of

operational parameters are such as compressive stress, cyclic compression, pressure,

temperature, chemical environment, sample orientation, inhomogeneity and layered

or graded structures.

Figure 2.6: Closed, blind and through pores in materials [35]

Porosity contain pores (cavities, channels, interstices) which are deeper than wide. It

also either describe the pores, or describe the cell/pore wall.

Figure 2.7: Different types of pores [35]

13

2.3 Typical Membrane Technique Preparation

There are various techniques available to produce porous polymeric structures. These

included: (i) particulate leaching/solvent casting, (ii) gas foaming, (iii) freeze drying,

(iv) electrospinning, and (v) phase inversion, to mention but a few as reported [36].

In general for each types of typical membrane technique preparation are as follow:

(i) Particulate leaching/solvent casting

The porogen leaching was first patented by Osada et al. [37]. This technique

involves dispersing water-soluble particles, such as salt, sugars, or polymer

spheres, in a matrix consisting of the scaffold material dissolved in an organic

solvent. After solvent evaporation, a composite of the polymer and porogen

remains. The composite is then immersed in water until complete dissolution

of the porogen occurs, resulting in a porous scaffold.

This technique may yield the following disadvantages such as skin of

nonporous polymer of the surface, non-homogeneous dispersion of pores,

lack of inner connectivity of the pores and remaining porogen within the

scaffold after porogen leaching.

(ii) Gas foaming

The use of carbon dioxide to create porosity in polymers has been studied by

Mikos et al. [38]. This technique avoids the use of organic solvents and high

temperatures, which permits incorporation of growth factors during

fabrication. Polymers are subjected to high-pressure carbon dioxide (800psi)

for 48 h to saturate the polymer with the gas. When the pressure is slowly

reduced to atmospheric pressure, carbon dioxide nucleates and grows within

the polymer, forming pores.

This is a simple method with suitable range of biomaterials and no

special equipment needed which attract a group of studies [39]. Fully

interconnecting pores and large pore interconnections can be fabricated.

However, one disadvantage of this technique is that many of the resulting

pores are closed (e.g., there is lack of pore inner connectivity). Modifications

to this technique include combining gas foaming with particulate-leaching,

and this resulted more pore inner connectivity.

14

(iii) Freeze drying

Gorna et al. [40] shows, the freeze-drying technique involves creating an

emulsion by homogenizing a polymer solvent solution and water. The

mixture is then rapidly quenched in liquid nitrogen, and the solvent and water

are removed by freeze-drying. Control of processing parameters, such as

volume fraction of the dispersed phase, results in control of the porosity.

Advantages of this technique include the ability to control pore size

from 15 to 200 microns, the ability to obtain more than 90%, and the

possibility of incorporating growth factors within the scaffolds.This technique

has been utilized many biocompatible polymers, including PGA, PLLA,

PLGA, and PPF blends. Inclusions of polymers like PPF in composite

scaffolds is beneficial for adjustment of compressive strength and properties

related to hydrophobicity.

According to Holannder et al. [41], this is a simple method with

suitable range of biomaterials and no special equipment needed. Fully

interconnecting pores and large pore interconnections can be fabricated. No

organic solvents are required. Some researcher using this method to studied

about nanopowder of rare earth tungsten for emission materials.

(iv) Electrospinning

Studied from [42], a modern method for creating porous scaffolds composed

of nano and microscale biodegradable fibers employs electrostatic fiber

spinning, or electrospinning, a technology derived from the electrostatic

spraying of polymer coatings. This method had been used by to form

microporous, non-woven poly(e-caprolactone) (PCL) scaffolds.

(v) Phase inversion

Kaushiva et al. [43] studied, phase inversion is a process one-phase solution

containing the membrane polymer transformed by a

precipitation/solidification process into two separate phases into separate

phases (a polymer-rich solid and polymer-lean liquid phase) as reported [43].

This process is most common used in generation of asymmetric structure in

membranes.

15

According to Bhattacharya et al. [45], the effect of surface properties on the

biocompatibility of biomaterials based on the same material; polyurethane

membranes with different surface properties were prepared. Phase inversion

technique was using as a method to fabricate the membranes. Ulbricht [46] reported

that microporous membranes with controlled pore size and structure were produce

from biodegradable polyurethane by using the modified phase inversion technique in

some studies.

In other cases, some researcher use two different types of phase inversion

technique which consisted wet phase inversion method and dry phase inversion

method to produces two different types of membranes (asymmetric and dense film).

The in-vitro response of human platelets was studied upon adherence to

films/membranes of polyurethane with different soft segments was studied [47].

Chalida et al. [48] has summarized, typically for membranes prepared by

phase inversion procedure, the properties of casting polymer solution have

significant influence on the structure of the resultant membranes. The more viscous

the solution, the smaller exchange rate between nonsolvent and solvent in polymer

film solution due to the rheological hindrance, thus resulting in membrane structure

with smaller pore size.

Most established membrane polymers however were not meet all the

performance requirements for a membrane dedicated to a particular application,

therefore membrane modifications are gaining rapidly increasing importance.

Acording to Chalida et al. [48] in his studied, based on the preparation of porous ion-

exchanged membranes with their characterizations was summarized that from

conventional precipitation method which by immersing the nascent polymer

membrane the nascent polymer film directly into water bath which casting solution

was took around 1min to form nascent film at room temperature.

As shown in Figure 2.6, sPES membranes with different porosities were

synthesized using a so-called phase inversion process, namely wet phase inversion

(precipitation), or dry phase inversion (solvent evaporation), or the combination of

these two processes. The membrane obtained from conventional precipitation

method by immersing the nascent polymer film directly into water bath (it took

casting solution around 1 min to form nascent film at room temperature.

As refer to Figure 2.8, (a1–3) was highly porous with largest pore size

compared to membranes prepared under other conditions. On the other hand, the

16

membrane obtained from solvent evaporation method exhibited dense and non-

porous structure as shown in Figure 2.8 (g1–3).

Typically for membranes prepared by phase inversion procedure, the

properties of casting polymer solution have significant influence on the structure of

the resultant membranes as reported by Sirkar et al. [49]. The more viscous the

solution, the smaller exchange rate between nonsolvent and solvent in polymer film

solution due to the rheological hindrance, thus resulting in membrane structure with

smaller pore size. If we suddenly immersed the casted film in water bath, the low

viscous polymer can be partly dissolved in water and membrane sheet could not be

formed.

Figure 2.8: SEM images of membranes prepared by phase inversion method with

different thickness and drying time [48]

17

2.4 Membrane Modification

According to Guo et al. [50], the parameter affecting the process of membranes such

as type of solvent, solvent-nonsolvent ratio, polymer concentration in solution,

polymer solidification time, and thickness of the polymer solution layer cast on a

substrate were investigate. The phase inversion process consists of the induction of

phase separation in a previously homogeneous polymer solution either by

temperature change, by immersing the solution in a non-solvent bath (wet process) or

exposing it to a non-solvent atmosphere (dry process).

As reported by Seymour et al. [51], in the thermal process, a low molecular

weight component usually acts as a solvent at high temperature and as a non-solvent

at low temperature. It is then removed after formation of the porous structure.

Usually the polymer solution is immersed in a non-solvent bath and a solvent-non-

solvent exchange leads to phase separation. The polymer-rich phase forms the porous

matrix, while the polymer-poor phase gives rise to the pores. The morphology is

usually asymmetric, with a selective skin on the surface.

The discussion so far implies that membrane materials are organic polymers

and,in fact, the vast majority of membranes used commercially are polymer-

based.Furthermore, polymeric membranes were dominating a very broad range of

industrial applications due to their following advantages:

(i) different types of polymeric materials are commercially available

(ii) a large variety of different selective barriers: porous, nonporous, charged and

affinity, can be prepared by versatile and robust methods

(iii)production of large membrane area with consistent quality is possible on the

technical scale at reasonable cost based on reliable manufacturing processes

(iv) Various membrane shapes (flat sheet, hollow-fiber, capillary, tubular, capsule

and formats including membrane modules with high packing density modules

can be produced.

Therefore, membrane modification is aimed either to minimize undesired

interactions, which reduce membrane performance (e.g., membrane fouling), or to

introduce additional interactions (e.g., affinity, responsive or catalytic properties) for

improving the selectivity or creating and entirely novel separation function. An

18

increasing number of methods and technologies investigated for polymer surfaces in

general are now being adapted to surface fuctionalization of polymeric membranes in

studied by Szwarc [52].

A key feature of a successful surface modification is a synergy between the

useful properties of the base membrane and the novel functional layer. In order to

achieve a stable effect, chemical modification is preferable over physical

modification. Attachment of functional moieties onto a membrane surface by

physical principles can be done via following ways:

(i) Adsorption/adhesion – the functional layer is only physically fixed on the

base material, and the binding strength can be increased via multiple

interactions between functional groups in the macromolecular layer and on

the solid surface.

(ii) Interpenetration via mixing between the added functional polymer and the

base polymer in an interphase.

(iii)Mechanical interpenetration (macroscopic entanglement) of an added

polymer layer and the pore structure of a membrane.

There are several means to modify polymer properties such as blending,

grafting, and curing: (a) Blending is the physical mixture of two (or more) polymers

to obtain the requisite properties, (b) Curing is polymerization of an oligomer

mixture forms a coating which adheres to the substrate by physical forces, and (c)

Grafting is a method wherein monomers are covalently bonded (modified) onto the

polymer chain as summarized by Kuitian et al. [53]. Curing gives a smooth finish by

filling in the valleys in the surface. The schematic representation of the above

membrane modification method is as refer to Figure 2.9.

19

Figure 2.9: Schematic representation of the methods of polymer modification [53]

(a) Blending

According to Kuitian et al. [54], polymer blends are defined as combination

and intimate mixtures of two kinds of two kinds of polymer, with no covalent

bonds between them. In most cases, blends are homogeneous on scales larger

than several times the wavelengths of visible light. While in principle, the

constituents of a blend are separable by physical means. Material prepared in

historically usually contain several percent of elastomer, dispersed in plastic

matrix, the plastic component predominates.

There are four basic of conception in which the principal methods of

mixing two kinds of polymer molecules include; (a) mechanical blending, (b)

graft copolymerization, (c) block copolymerization and (d) interpenetration of

polymer network. Therefore, the most important characteristic of a polymer

blend of two (or more) polymers is the phase behavior in which two basic

types of polymer blends; (a) miscible and (b) immiscible as summarized by

Kim et al. [55].

Miscibility in the context of polymer blends is defined as the degree

of mixing yield properties such as glass transition temperature and

permeability, expected of a single phase material. It may be homogeneous

20

down to the molecular level and associated with the negative value of the free

energy of mixing and the domain sizes comparable to the dimensions of the

macromolecular statistical segment. Concentration fluctuations of miscible

polymers would be expected to be of the order of several nanometer. In fact,

many blends noted to be miscible show structure of the order of several

nanometers when sensitive method [55].

In contrast, the vast majority of polymer pairs are immiscible with one

another. There are only few commercially important polymer blends based on

miscible and partially miscible (such as miscible within a low range of

concentration) polymer pairs. It is seldom possible to mix two or more

polymers and create a blend with useful properties [55].

Figure 2.10: SEM images that showed the effect of blending of chitosan with

PEG on membrane surface morphology [55]

According to Anbarason et al [56] in his studied about the effect of

blending of chitosan with PEG on surface morphology and crystallization, it

is well know that chitosan molecules are quite rigid, and the condition of

sample preparation normally has marked effect on crystallization. Through

this reason, chitosan film could present branch crystal, spherulites an so on.

Since both chitosan and PEG are crystalline structure polymers, they

may interact with each other in a certain manner so that the original

crystalline structures of each component have been disturb odor partially

damaged to a different extend, leading to various crystalline structures of the

blend film.

21

At first, pure chitosan appeared as a slender acicular structure

dispersed homogenously as shown in Figure 2.10 (a). With addition of PEG,

the surface structure changed markedly. The surface of chitosan appeared

more smooth and uniform, in which with addition of PEG as shown in Figure

2.10 (b), the surface of blend film displayed some irregular holes. As a result

of migration, many holes were generated on the surface of blend film.

Figure 2.11: Morphology of PVDF/PEO-b-PMMA polymer

membranes [56]

Likewise, Anbarason et al. [57] in his study about the formation of

pores is dependent on the mass fraction of PEO-b-PMMA, membranes shows

exhibit a large number of small pores as shown in Figure 2.11 (a), but then

the pore distribution on the surface of membrane becomes denser with

increase of PEO-b-PMMA as shown in micrograph (e). This can be attributed

to the high porosity of PVDF/PEO-b-PMMA blend macroporous membranes,

in which the pores in the bulk of the membranes are not well interconnected

find when PEO-b-PMMA content is low as shown in Figure 2.11 (a–c).

However, the pores become well interconnected when the mass

fraction of PEO is about 30% as shown in Figure 2.11 (d). In the solution of

22

PVDF/DMF/glycerin, with the evaporation of DMF (solvent), the phase

separation between PVDF and glycerin (non-solvent) forms a polymer-rich

phase and a polymer-poor phase. The former finally forms the polymer

matrix, while the latter forms the porous structure.

Instead, when preparing a new polymer blend from immiscible resins,

it is necessary to devise a specific strategy for compatibilizing the mixture to

provide for optimum physical performance and long-term stability. Although

there do exist a very small number of commercial blends of immiscible

polymers that are not compatibilized, most commercially available blends of

immiscible polymers have been compatibilized by some specific mechanism.

Polymer blends like low molecular weight solvents can exhibit

miscibility or phase separation and various levels of mixing in between the

extremes such as partial miscibility. The most important factor leading to

miscibility in low molecular weight materials is the combinatorial entropy

contribution which is very large compared to high molecular weight

polymers. This contribution is the reason that solvent-solvent mixtures offer a

much broader range of miscibility than polymer-solvent combinations. The

range of miscible combinations involving polymer-polymer mixtures is even

much smaller [58-59].

Due to some disadvantages such as poor mechanical properties of

polymers from renewable resources, or to offset the high price of synthetic

biodegradable polymers, various blend and have been developed. Blends

comprises of three kinds of polymers from renewable resources [60]:

(i) Natural polymers, such as starch, protein and cellulose.

(ii) Synthetic polymers from natural monomers, such as polylactic acid.

(ii) Polymers from microbial fermentation, such as polyhydroxybutyrate

are described with an emphasis on potential applications.

The majority of polymer blends containing elastomeric, thermoplastic,

liquid crystalline polymers are processed by melt extrusion at some point.

After melt extrusion with intensive mixing, the morphology of an immiscible

polymer blend on a microscopic scale will often consist of a dispersed phase

of the more viscous polymer in a continous matrix of less viscous polymer

23

depending upon relative amounts and viscosities of the two polymers in blend

as referred to Wang et al. [61].

The formation of optimum dispersed phase particle size and long-term

stabilization of blend morphology are critical if the blends is to have optimum

properties and in particular good mechanical properties. If this morphology is

not stabilized, then the dispersed phase may coalesce during any subsequent

heat and high stress treatment such as injection molding [62].

According to Samal et al. [63], an important aspect of all

compatibilization strategies is the promotion of morphology stabilization. It

be provided by sufficient interfacial adhesion and lowered interfacial tension

between the two polymer phases of the various compatibilization strategies

that have been devised an increasingly common method is either to add a

block, graft, or crosslinked copolymer of the two (or more) separate polymers

in the blend or to form such copolymer through covalent or ionic bond

formation during “Reactive Compatibilization” step.

Blends are usually made in two ways; (1) The first way is to dissolve

two polymers in the same solvent, and the (2) second way wait for the solvent

to evaporate and just eft with a blend at the bottom in beaker, presuming that

two polymers are miscible.

According to Bhattacharya [64], the basic strategies for “Reactive

Compatibilization” of two-phase polymer blends can divide into at least three

major categories:

(i) Co-crystallization of two phases

This particular strategy is limited to those cases in which an immiscible

polymer blend contains two semi-crystallize. It may also occur as a secondary

process in an intimately mixed blend containing a copolymer with

concomitant effects on blend properties [65].

(ii) In situ Immobilization of one phase: Dynamic Vulcanization

In these cases, a dispersed phase of cross linkable rubber is vulcanizable in

the presence of a matrix of a second, immiscible, non-vulcanizable polymer

during the residence time of melt processing. There are five key requirements

for preparing optimum composition by dynamic vulcanization [66].

24

(i) Good match between surfaces energies of the dispersed phase and the

matrix.

(ii) Low entanglement molecular length (high entanglement density) of

the rubber.

(iii) Crystalline plastic matrix.

(iv) Stable rubber and plastic at blend processing

(v) Availability of appropriate curing system for rubber under desired

processing conditions.

(iii) Addition of a third material as a compatibilizing agent

There are two basic options for addition of a copolymer compatibilizer to a

blend of immiscible polymers:

Addition of a separate compatibilizing agent

The copolymer can be synthesized in a separate step followed by addition to

the blend. It may be a third material which not derived from either of the

two immiscible polymers. This is also chemically unreactive analog of one or

both of the two immiscible polymers that has an attractive interaction with

each polymer [67].

Addition of a copolymer of the two immiscible polymers

Adding a copolymer to a blend of immiscible polymers is to form the

copolymer in situ which most economical and efficient process for a chemical

reaction during the extrusion process during establishment of the immiscible

phase morphology (Reactive Compatibilization).

Sanli et al. [68] reported that this manner is very ideal suited to act as

compatibilizing agent for an immiscible blend, where if the copolymer is at

the interface of the two phases, then the segments of the copolymer dissolve

in the respective bulk phases of the same identity. The copolymer acts as

emulsifying agent for the blend resulting in reduced interfacial energy and

improved interphase adhesion.

102

REFERENCES

1. Gogolewski, S.,Pennings, A.J., Lommen, E., Wildevuur, C.R.H. and

Neuwenhius, P. Growth of a Neo-Artery Induced by a Biodegradable

Polymeric Vascular Prosthesis. Makromolecular Chemical Rapid

Communications. 1983. 4(4): 213-219.

2. Baker, R.W. Membrane Technology and its Application. 2nd Edition. Menlo

Park California. John Wiley & Son. 2004.

3. Suprakas, S.R. and Bousmina, M. Biodegradable Polymers and Their

Layered Silicate Nanocomposites: In greening the 21st century materials

world. Progress in Materials Science. 2005. 50(8): 962–1079.

4. Walpoth, B.H., Rheiner, P., Cox, J.N., Faidutti, B., Megevand, R. and

Gogolewski, S. Implantations Chroniques De Membranes Et Protheses En

Polyurethanes. Helvetica Chimica Acta. 1988. 55(1-2): 62-157.

5. Heidi, L., Schreuder, G., Quoc, T., John, E., Walker, J.R., Joseph, D., Wander

and Wayne, E.J. Chemical and Biological Protection and Detection in Fabrics

for Protective Clothing. Materials Research Society. 2003. 28(8): 574-5

6. AnikaZafiah, M.R. Effect of Titanium Dioxide on Material Properties for

Renewable Rapeseed and Sunflower Polyurethane. International Journal of

Integrated Engineering (Issues on Mechanical, Materials and

Manufacturing Engineering. 2009a. 1: 15-22.

7. AnikaZafiah, M.R. Degradation Studies of Polyurethanes Based on Vegetable

Oils. Part 2; Thermal. Degradation and Materials Properties. Progress

Reaction Kinetic and Mechanism, Science Reviews. 2009b. 34: 1-43.

8. AnikaZafiah, M.R. (2010): Polymer from Renewable Materials, Science

Progress. 2010. 93(3): 285-300.

9. Sin, D.C., Miao, X., Liu, G., Wei, F., Chadwick, G., Yan, C. and Friis, T.

Polyurethane (PU) Scaffolds Prepared by Solvent Casting/Particulate

Leaching (SCPL) Combined with Centrifugation. 2009.

103

10. Strathmann, H. Production of Microporous Media by Phase Inversion

Process. In: Lloyd DR, Editor. Materials Science of Synthetic Membranes.

Washington, DC: American Chemical Society. pp; 65-195;1987

11. Lucas, M.D.E., Michael, A.R. and Meier. Plant oils: The Perfect Renewable

Resource for Polymer Science. European Polymer Journal. 2011. 47: 837–

852.

12. Huayu, T., Zhaohui, T., Xiuli, Z., Xuesi, C. and Xiabin, J. Biodegradable

Synthetic Polymers: Preparation, Functionalization and Biomedical

Application. Progress in Polymer Science. 2012. 37: 237– 280.

13. (a) Meier, M.A.R., Metzger, J.O. and Schubert, U.S. Plant oil renewable

resources as green alternatives in polymer science. Chemical Social. 2007.

36:802-1788; (b) Metzger, J.O. Fats and Oils as Renewable Feedstock for

Chemistry. European J. Lipid Science Technology. 2009. 111(9): 76-865.

14. Gogolewski, S., Walpoth, B. and Rheiner, P. Polyurethane microporous

membranes as pericardial substitutes. Colloid Polymer Science. 1987.

265(11): 7-971.

15. Klempner, D. and Frisch, K.C. The Handbook of Polymeric Foams and Foam

Technology. Munich, Germany. Hauser. 1991.

16. Mulder, M. Basic Priciples of Membrane Technology. Netherlands. Kluwer

Academic, Dodrecht. 1991.

17. Walpoth, B.H., Rheiner, P., Cox, J.N., Faidutti, B., Megevand, R. And

Gogolewski, S. Implantations chroniques de membranes et protheses en

polyurethanes. HelvChirActa. (1988); 55(1-2): 157-62.

18. Lonsdale, H.K. The Growth of Membrane Technology. Journal Membrane

Science. 1982. 10: 81-181.

19. Drioli, E. and Romano, M. Progress and New Perspectives on Integrated

Membrane Operations for Sustainable Industrial Growth. Industry

Engineering Chemical Research. 2001. 40: 1277.

20. Bhattacharyya, D. and Butterfield, D.A. Amsterdam. New Insights into

Membrane Science and Technology:Polymeric and Biofunctional

Membranes. Elsevier. 2003.

21. Zeman, L.J. and Zydney, A.L. Microfiltration and Ultrafiltration:Principles

and Applications. New Yok.Marcel Dekker Inc. 1996.

104

22. Drioli, Z.E. and Giorno, L. Biocatalytic Membrane Reactors: Aplication in

Biotechnology and the Pharmaceutical Industry. London, UK.Taylor &

Francis Publisher. 1999.

23. Ho, W. and Sirkar, K.K. Membrane Handbook. New York. Van Nostrand

Reihnold Publisher. 1992.

24. Zhang, R., and Ma, P.X. Porous Poly(L-Lactic Acid)/Apatite Composites.

Biomimetic Process Journal Biomedical Material. 1999.45: 285.

25. Witte, P.V., Dijkstra, P.J, Berg J.W.A. and Feijen, J. Phase separation

Processes in Polymer Solutions in Relation to Membrane Formation. Journal

Membrane Science. 1996. 117: 1–31.

26. Krause, B., Gohl, H. and Wiese, F., Ohlrogge, K. and Ebert K. Membrane.

Weinheim Wiley-VCH. 2006.

27. Marcano, J.S. and Tsotsis, T.T. Catalytic Membranes and Membrane

Reactors. Weinhem Wiley-CVH. 2002.

28. Klaaseen R., Feron, P.H.M and Jansen, A.E. Membrane Contactor in

Industrial Aplication. Trans Icheme Part A. Chemical Engineering Research

and Design. 2005. 83(A3): 234-246.

29. Breiter, S. M., Wiese, F., Wodetzki, A. and Schuster, O. Membrane

Technology: Membrane for Life Science. ASAIO Journal, 2004. 50:153.

30. Mulder, M. Basic Principles of Membrane Technology: 2nd

edition. Springer.

1996.

31. Koenhen, D. M., Mulder, M.H.V. and Smolders, C.A. Phase separation

phenomena during the formation of asymmetric membranes. Journal Applied

Polymer Science. 1997. 21(1): 199-215.

32. Lanza, R.P. And Vacanti, J. Principles of Tissue Engineering; Edition 3:

Academic Press. USA. 2007.

33. Atala, A. and Lanza, R.P. Methods of Tissue Engineering. United States of

America: Elsevier. 2002.

34. Tsui, Y.K. And Gogolewski, S. Microporous Biodegradable Polyurethane

Membranes for Tissue Engineering. Jornal Material Science: Material

Medical. 2009. 20:1729-1741.

35. Gupta, K.M and Jena, A.K. Pore Size Distribution in Porous Materials.

Proceedings of International Conference Filtration (3-4 November 1999).

Chicago, INDIA, 1999 .

105

36. Manole, A.V., Melnig, V., Zonda, R., Vacareanu, C. and Chiper, S. A. In-

Vitro Evaluation of Platelet Adhesion on Polyurethane Films and

Membranes. Romanian Journal Biophysical. 2008. 18(1): 29–37.

37. Osada, Y. and Nakagawa, T. Membrane Science and Technology. Marcel

Dekker Inc. 1992.

38. Mikos, A.G. and Temenoff, J.S. Formation of Highly Porous Biodegradable

Scaffolds for Tissue Engineering. Electronic Journal Biotechnol. 2000. 3(2):

9-114.

39. Xi, X., Nie, Z., Yang, J., Fu, X., Ji, D., and Zuo, T. Preparation and

Characterization of Non powder of Emission Materials by Freeze-Drying.

Journal of Nanoscience and Nanotechnology. 2005. 24(3): 199-272.

40. Gorna, K. and Gogolewski, S. Porous Biodegradable Polyurethane Scaffolds

for Tissue Repair and Regeneration. Journal Biomedical Material Research.

2006;79A(1): 128–38.

41. Hollander, A.P. and Hatton, P.V. Biopolymer Methods in Tissue

Engineering. Molecular Biology: Human Press. United Kingdom. Vol 238.

2004.

42. Yoshimoto, H., Shin, Y.M., Terai, H. and Vacanti, J.P. A Biodegradable

Nanofiber Scaffold by Electrospinning and its Potential for Bone Tissue

Engineering. Biomaterials. 2002. 24:2077-2082.

43. Kaushiva, A., Turzhitsky, V.M., Backman, V. and Ameer, G.A. A

Biodegradable Vascularizing Membrane: A Feasibility Study. Acta

Biomaterial. 2007. 3:631–642.

44. Kato, K., Uchida, E., Kang E., Uyama, Y. and Ikada, Y. Progress in Polymer

Science. 2003. 28: 209-259

45. Sperling, L.H. Introduction to Physical Polymer Science. 4th

ed. New Jersey:

John Wiley & Sons, Inc. 2006.

46. Ulbricht, M. Polymer. 2006. 47: 2217-2262.

47. Bhattacharya, A. Radiation and Industrial Polymers. Progress Polymer

Science. 2000. 25: 371–401.

48. Chalida, K., Seung H.M., Bradley, P., Ladewiga,, C.G.Q., Max, L. and

Lianzhou, W. Preparation of Porous Ion-Exchange Membranes (Iems) And

Their Characterizations. Journal of Membrane Science. 2011. 371: 37–44.

106

49. Sirkar, K.K., Winston, and Ho A.S. Membrane handbook. New York. Van

Nostrand Reinhold. 1992.

50. Guo, Y.Q., Tong, Z., Chen, M.C and Liang, X.H. Phase change behavior of

Polyethelene Glycol. Polymer Material Science Engineering. 2003. 19(5):

53-149.

51. Seymour, R.W., and Cooper, S. L. Thermal analysis of polyurethane block

polymers. Macromolecules 1973;6:48–53.

52. Szwarc M. Living Polymers:Their Discovery, Characterization and

Properties. Journal Polymer Science Part A: Polymer Chemical. 1998. 36: 9–

95.

53. Kuitian, T. and Obendorf, S.K. Surface Modification of Micro-porous

Polyurethane Membrane with Polyethylene glycol to Develop a Hybrid

Membrane. Journal of Membrane Science. 2006. 274(1-2): 150-158.

54. Kuitian, T. and Obendorf S.K. Hybrid Microporous Membranes Intended for

Protective Clothing, 15th

National Textile Center Conference. February 25-

27. Hilton Head Island, South Carolina. 2007.

55. Kim, M.J., Sea, B., Youn, K.H., and Lee, K.H. Morphology and Carbon

Dioxide Transport Properties of Polyurethane Blend Membranes.

Desalination. 2005. 193:43-50.

56. Anbarason, R., Jayasehara, J., Sudha, H., Nirmala, P.V. and Gopalon, A.

Peroxosalts Initiated Graft Copolymerization of O-Toluidine Onto Rayon

Fibre:A Kinetic Approach. Journal Polymer Material. 2000. 48(2): 199–223.

57. Anbarason, R., Jayasehara, J., Sudha, H., Nirmala, P.V. and Gopalon, A.

Peroxydisulphate Initiated Graft Copolymerization of O-Toluidine Onto

Synthetic Fibers—A Kinetic Approach. Applied Makromolecular Chemistry

and Physic. 2000. 201: 76-1869.

58. Celik, M. and Sacak, M. The Rate of Grafting and Some Kinetic Parameters

of the Graft Copolymerization of Methacrylic Acid on Poly(Ethylene

Terephthalate) Fibers With Azobisisobutyronitrile. Turkey Journal Chemical.

2000. 24(3): 74-269.

59. Bhattacharyya, S.N. and Maldas, D. Graft Copolymerization Onto

Cellulosics. Progress Polymer Science. 1983. 10: 171–270.

107

60. Khalil, M.I., Rafie E.M.H., Bendak, A. and Hebeish, A. Graft Polymerization

of Methylmethacrylate Onto Wool Using Dimethylaniline/Cu(II) System.

Cellulose Chemistry and Technology 1982. 16(5): 71- 465.

61. Wang, M., Wu, L.G, Mo, J.X., and Gao, C.J.C. The Preparation and

Characterization of Novel Charged Polyacrylonitrile/PES-C Blend

Membranes Used for Ultrafiltration. Journal Membrane Science. 2006. 274:

200–208.

62. Sun, T., Xu, P., Liu, Q., Xue, J. and Xie, W. Graft Copolymerization of

Methacrylic Acid onto Carboxymethyl Chitosan. European Journal Polymer.

2003. 39: 92-189.

63. Samal, S., Sahu, G., Lenka, S. and Nayak, P.L. Photoinduced Graft

Copolymerization (XI):Graft Copolymerization of Methylmethacrylate onto

Silk using Isoquinoline-sulphur Dioxide Charge Transfer Complex as the

Initiator. Journal Applied Polymer Science. 1987. 33(5): 8-1853.

64. Tang, Z.G. and Teoh, S.H. Microstructural Evaluation of an Elastomeric

Composite Membrane from Two Immiscible Polymers (UHMWPE and

polyurethane) for Soft Tissue Replacement, Colloids Surface B:

Biointerfaces. 2000: 19.

65. Wang, M., Wu L.G, Mo, J.X, Gao, C.J. The Preparation and Characterization

of Novel Charged Polyacrylonitrile/PES-C Blend Membranes used for

Ultrafiltration. Journal Membrane Science. 2006.274: 20–200

66. Cheriyan, M. Ultrafiltration and Microfiltration Handbook. USA: Technmic

Publishing Company. 1998: 9.

67. Tang, J.X., He, N.Y., Tan, M..J., He, Q.G and He, H.C, A Novel Substrate

For In Situ Synthesis of Oligonucleotide: Plasma-Treated Polypropylene

Microporous Membrane, Colloids Surface A. Physicochemical Engineering

Aspects. 2004. 242: 53.

68. Sanli, O. and Pulet, E., Solvent Assisted Graft Copolymerization of

Acrylamide on Poly(Ethylene Terephthalate)Films Using Benzoyl Peroxide

Initiator. Journal Applied Polymer Science. 1993. 47 :1–6.

69. Yamaki, T., Asano, M., Maekawa, Y., Morita, Y., Suwa, T., Chen, J.,

Tsubokawa, N., Kobayashi, K., Kubota, H. and Yoshida, M. Radiation

Grafting of Styrene Into Crosslinked PTFE Films and Subsequent Sulfonation

for Fuel Cell Applications. Radiation Physic and Chemistry. 2003. 67: 7-403.

108

70. Kaur, I., Barsola, R., Gupta, A. and Misra, B.N. Graft Copolymerization Of

Acrylonitrile and Methacrylonitrile onto Gelatin by Mutual Irradiation

Method. Journal Applied Polymer Science. 1994. 54: 9-1131.

71. Kaur, I., Misra, B.N., Chauhan, M.S, Chauhan, S. and Gupta, A. Viscometric,

Conductometric and Ultrasonic Studies of Gelatin-G-Polyacrylamide

Composite. Jornal Applied Polymer Science. 1996. 59: 97-389.

72. Kaur, I., Misra, B.N., Barsola, R. and Singla, K. Viscometric Studies of

Starch-G-Polyacrylamide Composites. Jornal Applied Polymer Science.

1993. 47: 74-1165.

73. Coessens V, Pintauer T, and Matyjaszewski K. Functional Polymers by Atom

Transfer Radical Polymerization. Progress Polymer Science. 2001. 26(7): 7-

337.

74. Zhang, R., and Ma, P.X. Poly(Alpha-Hydroxy Acids)/Hydroxyapatite Porous

Composites for Bone Tissue Engineering: 1. Preparation and Morphology.

Jornal Biomedical Material Research. 1999. 44:446

75. Schamberg, E. and Hoigne, J. Radical And Radiation-Induced Grafting of

Some Synthetic High Polymers Within the Temperature Range of Their Glass

Transition. Journal Polymer Science Part A: Polymer Chemistry. 1970. 8: 8-

693.

76. Stehling, U.M., Malmstrom, E.E., Waymouth, R.M. and Hawker, C.J.

Synthesis of Poly(Olefin)Graft Copolymers by a Combination of Metallocene

and Living Free Radical Polymerization Techniques. Macromolecules. 1998.

31: 8-4396.

77. Wang, J.S, Matyjaszewski, K. Controlled Living Radical Polymerization.

Atom Transfer Radical Polymerization in the Presence of Transition-Metal

Complexes. Journal American Chemical Society. 1995. 117: 5-614.

78. Matyjaszewski, K. Transition metal catalysis in controlled radical

polymerization: atom transfer radical polymerization. Journal Chemical

European. 1999. 5: 102-3095.

79. Bhattacharya, A and Misra, B.N. Grafting: A Versatile Means To Modify

Polymers Techniques, Factors and Applications. Progress Polymer. Science.

2004. 29:767–814.

80. Uflyand, I.E., Ilchenko, I.A., Sheinker, V.N. and Savostyanov, V.S. Polymers

Containing Metal Chelate Units. VI. Post-Graft Polymerization of Metal

109

Chelate Monomers Based on 1-Phenyl-4-Methyl Pent-4-Ene-1,3 Dione.

Reaction Function Polymer. 1992. 17: 96-289.

81. Chen, J., Iwata, H., Maekawa, Y., Yoshida, M. and Tsubokawa, N. Grafting

of Polyethylene by G-Radiation Grafting onto Conductive Carbon Black and

Application as Novel Gas and Solute Sensors. Radiation Physic and

Chemistry. 2003. 67(3–4): 397–401.

82. Stehling, U.M., Malmstrom, E.E., Waymouth, R.M. and Hawker, C.J.

Synthesis of Poly(Olefin)Graft Copolymers by A Combination of

Metallocene and Living Free Radical Polymerization Techniques.

Macromolecules. 1998. 31: 8-4396.

83. Kuitian, T and Obendorf S.K., Development of Antimicrobial Microporous

Polyurethane Membranes, 34th ACS Northeast Regional Meeting. October 5-

7. Binghamton, NY. 2006.

84. Kuitian, T. and Obendorf, S.K. Development of an Antimicrobial and

Breathable Microporous Polyurethane Membrane, the Fiber Society Annual

Conference. October 10–12, Tennessee. 2006.

85. Marmey, P., Porte, M.C. and Baquey, C. PVDF Multifilament Yarns Grafted

with Polystyrene Induced by G-Irradiation: Influence of The Grafting

Parameters on the Mechanical Properties. Nuclear Instrument and Methods.

2003. 208:33-429.

86. Bhattacharya, A., Das, A. and De, A. Structural Influence on Grafting of

Acrylamide Based Monomers on Cellulose Acetate. Industry Journal

Chemical Technology. 1998. 5: 8-135.

87. Lips, P.A.M., Velthoen, I.W., Dijkstra, P.J., Wessling, M. and Feijen, J. Gas

Foaming of Segmented Poly(ester amide) films. Radiation Physic and

Chemistry. 2005.46(22):9396-9403

88. Aich, S., Bhattacharya, A. and Basu, S. Fluroscence Polarisation of N-Vinyl

Carbazole on Cellulose Acetate Film And Electron Transfer with 1,4

Dicyanobenzene. Radiation Physic and Chemistry. 1997. 50(4): 347–54.

89. Maldas D. Radiation Induced Grafting of Styrene and Acrylamide on

Cellulose Acetate from A Binary Mixture. Thesis, University of Calcutta.

1983.

90. Wenzel, A., Yamgishita, H., Kitamoto, D., Endo, A., Haraya, K., Nakane, T.,

Hanai, N., Matsuda, H., Kamuswetz, H. and Paul, D. Effect of Preparation

110

Condition of Photoinduced Graft Filling Polymerized Membranes on

Pervaporation Performance. Journal Membrane Science. 2000. 179: 69–77.

91. Yamaguchi, T., Yamahara, S., Nakao, S. and Kimura, S., Preparation of

Pervaporation Membranes for Removal of Dissolved Organics from Water by

Plasma-Graft Filling Polymerization. Journal Membrane Science. 1994. 95:

39–49.

92. Chen, T., Kumar, G., Harries, M.T, Smith, P.J. and Payne, G.F. Enzymatic

Grafting of Hexyloxyphenol onto Chitosan to Alter Surface and Rheological

Properties. Biotechnology Bioengineering. 2000. 70(5): 73-564.

93. Kaplan, D. Biopolymers from Renewable Resources. Germany: Springer.

Verlag Berlin Heidelberg. 1998.

94. Smith, W.F. and Hashemi. Foundations of Materials Science and

Engineering. 4th

ed. New York: McGraw-Hill. 2006.

95. Geddie, U.W. Polymer Physics. Netherlands: Kluwer Academic Publishers.

1999.

96. Meier, M.A.R., Metzger, J.O. and Schubert. U.S. Plant Oil Renewable

Resources as Green Alternatives. Polymer Science Chemical Social Reviews.

2007. 36: 1788–1802.

97. Narine, S.S. and Kong, X. Vegetable Oils in Production of Polymers and

Plastics. Bailey’s Industrial Oil and Fat Products. 6th

ed. John Wiley & Sons.

2005.

98. Kaith, B.S. and Kaur, I. Cellulose Fibers: Bio and Nano-Polymer

Composites: Green Chemistry Technology. New York: Springer. 2011.

99. Hill, K. Fats and Oils as Oleochemical Raw Materials. Pure Applied

Chemical. 2000. 72(7): 1255–1264.

100. Liu, Y. New Biodegradable Polymers from Renewable Resources.

Department of Polymer Technology, Royal Institute of Technology (KTH).

Sweeden. 2000.

101. Guo A, Javni I, Petrovic Z. Rigid Polyurethane Foams based on Soybean oil.

Journal Applied Polymer Science. 2000. 77: 467–7

102. Burdick, J.A. and Mauck, R.L. Biomaterials for Tissue Engineering

Applications: A Review of the Past and Future Trends. New York: Springer.

Verlag/Wein . 2011.

111

103. Wu, J., Gong, X., Chen, L., Xia, H. and Hu., Z. Preparation and

Characterization of Isotropic Polyurethane Magnet Archaeological Elastomer

Through In Situ Polymerization. Journal of Applied Polymer Science. 2009.

114: 901-910.

104. Williams, C.K. And Hillmyer, M.A. Polymers from renewable resources: A

Perspective for a Special Issue of Polymer Reviews, Polymer Reviews. 2008.

48: 1–10.

105. Yoshimoto, H., Shin, Y.M., Terai, H. and Vacanti, J.P. A Biodegradable

Nanofiber Scaffold by Electrospinning and its Potential for Bone Tissue

Engineering. Biomaterials. 2002. 24: 2077-2082.

106. Lucas, N., Bienaime, C., Belloy, C., Queneudec, M., Silvestre, F. (2008).

Polymer Biodegradation: Mechanisms and Estimation Techniques.

Chemosphere. 2008. 73: 429–442.

107. Koutny, M., Lemaire, J., Delort, A. M. (2006). Biodegradation of

Polyethylene Films with Prooxidant Additives. Chemosphere, vol 64. pp

1243–1252.

108. Gopalakrishnana, S. and Sujathaa, R. Synthesis and Thermal Properties of

Polyurethanes from Cardanolfurfural Resin. Journal Chemical Pharmacy

Research. 2010. 2(3): 193-20

109. Allport, D., Gilbert, D., and Outterside, S. MDI and TDI: Safety, Health and

the Environment. John Wiley & Sons, Ltd, West Sussex, England. 2003,

110. Randall, D.; Lee, S. (2003). The Polyurethanes Book. New York: Wiley.

ISBN 978-0-470-85041-1.

111. Andersen, F.A. Special Report: Reproductive and Developmental Toxicity of

Ethylene Glycol and Its Ethers". International Journal of Toxicology. 1999.

112. Nakamura, K. Proceedings of The International Workshop on

Environmentally Compatible Materials and Recycling Technology. Tsukuba,

Japan, 15-16, Nov. 1993: 239-244

113. Weissermel, K. and Arpe, H.J. Industrial Organic Chemistry: Important Raw

Materials and Intermediates. Wiley-VCH. 45–46.

114. Dimethylformamide". Spectral Database for Organic Compounds. Japan:

AIST. Retrieved 2012-06-28.

115. Polymer Thin Films from Renewable Resources.

2010/PT/TMI/PTA1.81/APP/0479/PCG. DEC 2010.

112

116. AnisNS, A.B. Preliminary Fabrication of Biodegradable Polymer Membranes

from Renewable Resources. Universiti Tun Hussein Onn Malaysia, 2011.

117. ASTM International. Standard Test Method for water absorption of thin

plastic sheeting. U.S., D 570-81(1994b). 1994,

118. Andrade, J.D. Interfacial Phenomena and Biomaterials. Medical Instrument.

1974. 7: 20-110

119. ASTM International. Standard Test Method for Tensile Properties of Thin

Plastic Sheeting. U.S., D882-02. 2002,

120. ASTM International. Standard Test Method for Tear Properties of Thin

Plastic Sheeting. U.S., D1922. 2002.

121. Gopalakrishnana, S. and Sujathaa, R. Synthesis and thermal properties of

polyurethanes from cardanolfurfural resin. Journal Chemistry Pharmacy

Research. 2010. 2(3): 20-193

122. Barth, C., Goncalves, M.C, Pires, A.T.N., Roeder, J., and Wolf, B.A.

Asymmetric Polysulfone and Polyethersulfone Membranes: Effects of

Thermodynamic Conditions During Formation on Their Performance.

Journal Membrane Science. 2000. 169: 287–299.

123. Barzin, J. and Sadatnia, B. Theoretical Phase Diagram Calculation and

Membrane Morphology Evaluation for Water/Solvent/Polyethersulfone

System. Polymer. 2007. 48: 1620–1631.

124. Conesa, A., Gumi, T. and Palet, C. Membrane Thickness and Preparation

Temperature as Key Parameters for Controlling the Macrovoid Structure of

Chiral Activated Membranes (CAM). Journal Membrane Science. 2007. 287:

29–40.

125. Warrer, K., Karring, T., Nyman, S., and Gogolewski, S. Guided Tissue

Regeneration Using Biodegradable Membranes of Polylactic Acid or

Polyurethane. Journal of Clinical Periodontology. 1992. 19: 40-633.

126. Patil, D.R. and Fanta, G.F. Graft Copolymerization of Starch with

Methylacrylate: An Examination of Reaction Variables. Journal Applied

Polymer Science. 1993. 47: 72-1765.

127. Mulder, M. Basic principles of membrane technology: 2nd

edition. Springer.

1996

113

128. Strathmann H. Production of Microporous Media by Phase Inversion Process.

In: Lloyd DR, Editor. Materials Science of Synthetic Membranes. American

Chemical Society. Washington, DC. 1985. 165-195

129. Kuitian. T and S.K. Obendorf S.K. Development of an Antimicrobial

Microporous Polyurethane Barrier Membrane. Journal of Membrane Science.

2007. 199: 289

130. Kuitian, T. and Obendorf, S.K. Surface Modification of Micro-porous

Polyurethane Membrane with Polyethylene glycol to Develop a Hybrid

Membrane. Journal of Membrane Science. 2006, 274(1-2):150-158.

131. Kuitian, T and Obendorf S.K. Development of Novel Membranes for High

Performance Protective Clothing , The Hilton Head Beach Marriott & Golf

Resort:17-19, February. Hilton Head Island, South Carolina, 2006.

132. Seungsin, L. and Obendorf S.K, Developing Protective Textile Materials as

Barriers to Liquid Penetration Using Melt-Electrospinning. Journal of

Applied Polymer Science (in press).

133. Seungsin, L. and Obendorf S.K. Barrier Effectiveness and Thermal Comfort

of Protective Clothing Materials. Journal of the Textile Institute. 2007. 98:

87-97.

134. Recio, R., Pradanos, P., Hernandez, A., Shishatskiy, S., Peinemann K. V.,

Bottino, A.and Capannelli, G., Asymmetric Membranes for Gas Separation.

Different Technique to Determine the Active dense Skin Thickness, Marie

Curie Workshop on New Materials for Membranes, Geestacht. 2007.

135. Recio, R., Pradanos, P., Hernandez, A., Tejerina, F., Shishatskiy, S. and

Peinemann K.V. Characterization Con AFM de Membranes Mixtas de

Inversion de Fase para Separacion de Gases, Proc. 5 Congreso

Iberoamericano de Ciencia y Technologia de Membranes (CITEM 2005),

Valencia. 2005.

136. Nunes, S.P. and Peinemann K.V. Membrane Technology in the Chemical

Industry. Wiley-VCH, Weinheim. 2001.

137. Guo, Y.Q., Tong, Z., Chen, M.C and Liang, X.H. Phase Change Behavior of

Polyethelene Glycol. Polymer Material Science Engineering. 2003. 19(5):

53-149.

138. Medical Bib. Bahagian Pergigian, Pusat Kesihatan Universiti Tun Hussein

Onn (UTHM).

114

139. Oprea, S. and Vlad, S. Polyurethane materials for passive isolation bearings.

Journal of Optoelectronics and Advanced Materials. 2006. 8(2). 675 – 681

140. Jin, C., Christensen, P.A., Egerton, T.A., Lawson, E.J. And White, J.R. Rapid

Measurement of Polymer Photo-degradation by FTIR Spectrometry of

Evolved Carbon Dioxide. Polymer Degradation and Stability. 2006. 91:

1086-1096.

141. Price, D.M., Hourston, D.J. and Dumont, G. Thermogravimetry of

Polymers.Encyclopedia of Analytical Chemistry: John Wiley & Sons Ltd,

Chichester, 2000: 8094–8105.

142. Chattopadhyay, D.K. and Webster, D.C. (2006). Thermal Stability and Flame

Retardancy of Polyurethanes. Progress in Polymer Science. 2006. 3: 2389-

2356.

143. Huang, S.L., Chang, P.H., Tsai, M.H. and Chang, H.C. Properties and

Pervaporation Performances of Crosslinked HTPB-based polyurethane

Membranes. Separation and Purification Technology. 2007. 56: 63–70.