PERPUSTAKAAN UMP

Ill Ill Ill Ill I UU 1111 IIII III 0000073693

PREPARATION AND CHARACTERIZATION OF POLY(HYDROXAMIC ACID)

CHELATING RESIN FOR METAL IONS REMOVAL FROM WATER

NUR 'ATIKAH BINTI ABDULLAH

Report submitted in partial fulfilment of the requirements for the award of Bachelor of Applied Science (Honours) in Industrial Chemistry

Faculty of Industrial Science and Technology

Universiti Malaysia Pahang

2012

ABSTRACT

Graft copolymerization of methyl acrylate (MA) onto kenaf cellulose was carried out using redox method in which ammonium ferrous sulphate was used as an initiator. The poly (methyl acrylate) grafted kenaf cellulose was obtained at 55 °C after 2 hours stirring, and purified acrylic polymer-grafted cellulose was characterized by FTIR and ICP-MS analysis. There in, the ester and nitrile functional groups of the grafted copolymers were reacted with hydroxylamine solution for conversion into the hydroxamic acid ligands. The chelating behavior of the prepared ligands toward some metal ions was investigated using batch technique. The adsorptions of metal ions onto ligands were dependent on pH parameter and the amount adsorbed towards metal ions following order: Zn2 > Fe3 > Cr> Cu2 > Ni2.

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ABSTRAK

Pempolimeran metil ekrilat (MA) dicangkukkan dengan selulosa kenaf melalui kaedah redoks di mana ferum ammonium sulfat telah digunakan sebagai bahan pemula. Pempolimeran dilakukan pada suhu 55 °C selama 2 jam dan dilakukan pencirian dengan menggunakan FTIR dan ICP-MS. Terdapat ester dan kumpulan nitril dalam kopolimer yang telah bercantum dan bertindak balas dengan larutan hidroksilamin untuk bertukar ke ligan asid hidrokamilc. Sifat 'chelating ligands' yang bersedia terhadap beberapa ion logam telah disiasat dengan dengan menggunakan teknik 'batch'. penjerapan ion logam ke ligan bergantung kepada parameter pH dan jumlah yang terserap ke arah ion logam

2+ 3+ 3+ 2+ mengikut susunan yang berikut: Zn > Fe > Cr > Cu > Ni

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TABLE OF CONTENTS

Page

SUPERVISOR'S DECLARATION

STUDENT'S DECLARATION

DEDICATION iv

ACKNOWLEDGEMENT v

ABSTRACT

ABSTRAK vii

TABLE OF CONTENT viii

LIST OF TABLES xii

LIST OF SCHEME xiii

LIST OF FIGURES xiv

LIST OF SYMBOLS xv

LIST OF ABBREVIATIONS xvi

CHAPTER 1— INTRODUCTION

1.1 Background

1.1.1 Softwood Of Cellulose 1

1.1.2 Ion Exchange Resins 3

1.1.3 Chelating Resins 4

1.1.4 Hydroxamic Acid 4

1.1.5 Effect Heavy Metals Toxicity To Health And 4

Environment

1.1.6 Removal Of Heavy Metal Ions From Wastewater 6

1.2 Objectives Of The Research 7

1.3 Scope Of The Study

1.4 Problem Statements 8

CHAPTER 2- LITERATURE REVIEW

2.1 Graft Copolymerization 10

2.2 Grafting Initiated By Chemical Means 12

2.2.1 Redox Method 14

2.2.1.1 Persulfate Systems 14

2.2.1.2 Fenton's Reagent (H202 / Fe) Systems 15

2.2.1.3 Ceric Ion As Initiator 17

2.2.2 Chain-Transfer Initiation 18

2.2.3 Adsorbents Produced By Direct Modification Of 19

Cellulose

2.2.3.1 Esterification 20

2.2.3.2 Halogenation 20

2.2.3.3 Etherification 21

2.2.3.4 Oxidation 21

2.3 Synthesis Of Graft Copolymers By Chemical Initiation 22

2.3.1 Initiation By Metal Ions 24

2.3.1.1 Manganese (III) 24

2.3.1.2 Vanadium(V) 27

2.3.1.3 Cobalt(III) 28

2.3.1.4 Chromium(VI) 30

2.3.1.5 Copper(II) 32

2.3.1.6 Iron(III) 33

2.3.1.7 Cerium(IV) 35

2.4 Chelating Ion Exchangers 39

2.5 Chelating Groups 40

2.6 Polymeric Matrices 40

2.7 Application Of Chelating Ion Exchangers 41

2.8 Poly(Hydroxamic Acid) Resin

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CHAPTER 3— METHODOLOGY

3.1 Introduction 47.

3.2 Materials And Methods 48

3.3 Preparation Of Cellulosic Material From Kenaf Wood 48

3.4 Graft Copolymerization Of Methyl Acrylate Onto Softwood Of 48

Cellulose

3.5 Synthesis Of Poly(Hydroxamic Acid) Ligand 49

3.6 Extraction Of Metal Ions By Batch Technique 50

3.7 FTIR Analysis 50

CHAPTER 4- RESULT AND DISCUSSION

4.1 Introduction 51

4.2 Result

4.2.1 Preparation Of Cellulosic Material And Graft 51

Copolymerization

4.2.2 Synthesis Of Poly(Hydroxamic Acid) Ligands 53

4.2.3 FTIR Analysis 53

4.2.4 Reaction Mechanism 54

4.2.5 Physical Appearance Of Chelate Complex 56

4.2.6 ICP-MS Analysis 57

4.3 Discussion

4.3.2 Sorption Of Metals By Batch Technique

4.3.2.1 Effect Of pH On Cu 58

4.3.2.2 Effect Of pH On Fe 60

4.3.2.3 Effect Of pH On Cr 61

4.3.2.4 Effect Of pH OnNi 62

4.3.2.5 Effect Of pH On Zn 64

4.3.3 Factors Affecting Metal Ion Adsorption 67

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4.4 Concusion 68

CHAPTER 5— CONCLUSION

5.1 Conclusion 69

5.2 Recommendation For The Future Research 69

REFERENCES 71

APPENDIXES 75

A Standard Table Of Characteristic IR Absorptions 77

B Calculation

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LIST OF TABLE

Table No Title Page

Table 2.1 Cellulose modification methods with various chemical reagents 22 and associated functional groups

Table 2.2 Grafting techniques and associated advantages and disadvantage 23

Table 2.3 Chemically modified and grafted celluloses and associated 24 adsorption capacities

Table 4.1 F.TIR analysis 54

Table 4.2 Physical appearance of chelate complex

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Table 4.3 Sorption of Metals by Batch Technique

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LIST OF SCHEME

Scheme no Title Page

Scheme 1.1 Exchange of ions between an insoluble (polymer) phase and a 3 solution phase.

Scheme 2.1 A similar mechanism has been suggested when other metal ion 15 like Ag.

Scheme 2.2 Ferrous Iron(II) is oxidized by hydrogen peroxide to ferric 16 iron(III)

Scheme 2.3 Mechanism of initiation of graft copolymerization onto 16 cellulose with either H202

Scheme 2.4 The reaction of ceric ion in aqueous solution with cellulose 17

Scheme 2.5 The decomposition of the complex between Mn 3 and organic 25 substrate

Scheme 2.6 The radicals formed from the dissociation radical ion initiates 26 the polymerization

Scheme 2.7 Redox system involving Co 3+ 29

Scheme 2.8 General mechanism of chromic acid oxidations 31

Scheme 2.9 The formation of unstable species Cr 6 and Cr5 was responsible 32 for the initiation

Scheme 2.10 Formation of amino radicals

Scheme 2.11 Mechanism of oxide/Fe2 system 34

Scheme 2.12 The polymerization of methyl methacrylate polymerization 36 initiated by ceric ions

Scheme 2.13 Polymerization of phenylalanine by ceric ions 37

Scheme 2.14 Polymerization of acrylamide are chelating 38 polyaminocarboxylic acids with Ce(IV)

II

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LIST OF FIGURES

Figure No. Title Page

Figure 2.1 Schematic diagram of argon glow discharge treatment for the 11 immobilization of surfactants

Figure 2.2 Schematic representation of the methods of polymer modification 13

Figure 2.3 General step in the chain transfer method 18

Figure 3.1 Flow Chart of the Laboratory Work 47

Figure 4.1 Effect pH on absorbance capacity of Cu(II) ions by the ligands 58

Figure 4.2 Effect pH on absorbance capacity of Fe(II) ions by the ligands 60

Figure 4.3 Effect pH on absorbance capacity of Cr(II) ions by the ligands 61

Figure 4.4 Effect pH on absorbance capacity of Ni(II) ions by the ligands 63

Figure 4.5 Effect pH on absorbance capacity of Zn(II) ions by the ligands 65

Figure 4.6 pH vs Amount absorbed (mmollg) 66

LIST OF SYMBOLS

A Alpha

Sigma bond

Pi bond

qe Equilibrium sorption amount

Co Initial concentration of metal solution

Ce Equilibrium concentration of metal

V Volume of metal solution

L Mass of polymeric ligands

M Mol weight of specific metal

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LIST OF ABBREVIATIONS

AA Acrylamide

AGU Anhydro Glucose Units

AN Acrylonitrile

As Arsenic

ATRP Atom Transfer Radical Polymerization

CAN Cerium (Iv) Ammonium Nitrate

Cd Cadmium

Cell-PEI Cellulose - Polyethyleneimine

Cr Chromium

DSC Differential Scanning Calorimetry Analysis

DTPA Diethylenetriamine Pentaacetic Acid

EDTA Ethylenediamine Tetraacetic Acid

FTIR Fourier Transform Infrared Spectroscopy

Hg Mercury

ICP-MS Inductively Coupled Plasma Mass Spectrometry

IR Infrared

M Monomer

MA Methyl Acrylate

MAam Methacrylamide

MMA Methyl Methacrylate

NDA Nitrilotriacetic Acid

P Polymer

PAA/PAAm Poly(Acrylamide)

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PAN Poly(Acrylonitrile)

Pb Lead

PHA Poly(Hydroxamic Acid)

PMA Poly(Methyi Acrylate)

TGA Thermogravimetric Analysis.

Ti Thallium

FAAS flame atomic absorption spectrometry

PFR phthaiic acid-formaldehyde-resorcinol

DDTC Diethyldithiocarbamate

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CHAPTER 1

INTRODUCTION

1.1 BACKGROUND

1.1.1 Softwood of Cellulose

Cellulose is one of many polymers found in nature (Simon et al., 2011). Wood,

paper, and cotton all contain cellulose. It occurs in almost pure form in cotton fiber and

in combination with other materials, such as lignin and hemicelluloses, in wood, plant

leaves and stalks, etc. The principle and main routes of direct modification of the

cellulose for the preparation of adsorbent materials are esterification, etherification,

acetyl formation, hydrolysis, oxidative degradation, and thermal degradation. For

industrial use, cellulose is mainly used to produce paperboard and paper. Converting

cellulose from energy crops into bio-fuels such as cellulosic ethanol is under

investigation as an alternative fuel source. The efficient conversion of inexpensive

cellulosic materials into fuel ethanol is expected to be the needed breakthrough in

producing affordable and renewable liquid fuel (Ye Sun and Jiayang Cheng, 2002). To

break down cellulosic biomass into fermentable reducing-sugars, enzymatic hydrolysis

is considered the most promising vehicle. However, cellulosic bio-mass is more difficult

and more expensive to convert into ethanol than corn grain based on current

technologies; One of the main obstacles is the poor enzymatic hydrolysis of cellulose. To

make cellulose susceptible to hydrolysis, a pretreatment process is needed to remove

lignin, reduce the cellulose crystallinity, and increase the cellulose porosity (Galbe and Zacchi, 2002).

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X-ray diffraction can showed significant differences in monoclinic angle of two

groups of hardwoods and softwoods. These differences were reduced by chemical

treatments (hydrolysis and delignification). Electron reflection showed little difference.

From these observations it is concluded that the structural variations of cellulose crystals

between hardwoods and softwoods are preferable to non-crystalline substances such as

amorphous cellulose, polyposis and lignin which may have some connections with

cellulose crystals in the cell walls.

Softwoods are the dominant lignocelluloses feedstock for bioconversion in the

Northern hemisphere and are viewed as a potential source of fermentable carbohydrate

for fuel-ethanol production in Canada, Sweden and US. In British Columbia, an

estimated 2.2 million tons of surplus wood residues are generated per year. Conversion

of these residues into fuel ethanol and other commodity chemicals provides an attractive

opportunity for more sustainable development of forest resources.

A primary techno-economic challenge in all lignocelluloses to ethanol

bioconversion processes is overcoming the recalcitrance of the cellulose fraction to

enzymatic hydrolysis. Cellulose is intrinsically resistant to enzyme attack and is further

protected by the surrounding matrix of lignin and hemicelluloses in lingo-cellulose.

Softwood lignocelluloses are considered particularly recalcitrant for hydrolysis owing to

the amount and nature of the lignin component. Steam explosion is one of the most

intensively studied pretreatment methods for bioconversion of softwood materials. The

steam explosion process uses high temperature and pressure, followed by sudden

release, to separate individual fibers within the wood. Meanwhile, most of

hemicelluloses is hydrolyzed and removed during steam explosion, contributing to the

improved susceptibility of the substrate. However, the steam-explosion process does not

result in net delignification: the lignin content after steam explosion is actually increased

due to the removal of hemicelluloses.

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1.1.2 Ion Exchange Resins

Ion exchange resins bearing chelating functional groups have long been of

interest for removing metals from water. The design of chelating ligands depends on the

stability of the basic macromolecular network and its ability to add on the desired

chelating functional groups. Because the alkali and alkaline earth metals occur in

relatively high concentrations in natural waters, a desirable property of metal chelating

ligands having useful environmental or commercial application is their ability to bind

heavier elements selectively. They should be able to bind the heavier transition, rare

earth, and main group metal ions in the presence of high concentration of calcium,

magnesium, sodium and potassium. The different ion exchange resins consist of

different polymers and different ligands covalently bound to the polymers. Ion exchange

resins are useful because of the insolubility of the resin phase. After contact with the ion

containing solution, the resin can be separated by filtration. Ion exchange resins have

been used in water softening, removal of toxic metals from water in the environment,

wastewater treatment, hydrometallurgy, sensors, chromatography and bio -molecular

separations. They have also been used as catalysts, both in place of homogeneous

catalysts such as sulfuric acid and to immobilize metallic catalysts.

[Polymer] - X A + B - [Polymer] - X B + A

Anion exchange resin

[Polymer] - Y C + D - [Polymer] - Y D + C

Cation exchange resin

Scheme 1.1: Exchange of ions between an insoluble (polymer) phase and a solution phase.

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1.1.3 Chelating resins

Chelating resins having a wide applicability for the selective removal of metal

ions and polymeric' substances with the ability to complex with metal ions are very

common. These materials, which have polyelectrolyte characteristics, have a very large

number of sorption sites per macromolecule and have been used to remove toxic and

polluting metal ions from wastewater and mine water (Faraj et al., 2009). Chelating resin

can be used to remove trace metals from water, reagents and macromolecular samples.

Chelating resin has a high preference (Luthor et al., 2001). Its selectivity for divalent

ions over monovalent ions is high (5,000:1) and it has a very high attraction for

transition metals, even in concentrated salt solutions. The chelating polymer materials

are mainly used in analytical, industrial and radiochemical laboratories.

1.1.4 Hydroxamic acid

Hydroxamic acids are versatile chelating agents forming very stable complexes

with a large number of metal. Hydroxamic acids have been known for their chelation

ability with heavy metals. They have been found to be effective chelating ligands with

the ions such as V 5", Fe 3+, M06"', Ti4", Hg2", Cu2", and UO2 . Number of chelating

polymers, containing hydroxamic acid group, have been prepared from various starting

materials using different methods. Po!y(hydroxamic acid) was synthesized from

polyacrylamide at different conditions. Polyhydroxamic acids have found wide

applications in the field of analytical chemistry (Khaled et al., 2011).

1.1.5 Effect heavy metals toxicity to health and environment

The term heavy metal refers to any metallic chemical element that has a

relatively high density and is toxic or poisonous at low concentrations. Examples of

heavy metals include mercury (Hg), cadmium (Cd), arsenic (As), chromium (Cr),

thallium (TI), and lead (Pb). Heavy metals are natural components of the Earth's crust.

Heavy metal also is a member of a loosely-defined subset of elements that exhibit

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metallic properties. It mainly includes the transition metals, some metalloids, lanthanides

and actinides. They cannot be degraded or destroyed. To a small extent they enter our

bodies via food, drinking water and air. As trace elements, some heavy metals

(e.g. copper, selenium, zinc) are essential to maintain the metabolism of the human

body. However, at higher concentrations they can lead to poisoning. Heavy metal

poisoning could result, for instance, from drinking water contamination (e.g. lead pipes),

high ambient air concentrations near emission sources, or intake via the food chain.

Heavy metals are dangerous because they tend to bioaccumulate.

Bioaccumulation means an increase in the concentration of a chemical in a biological

organism over time, compared to the chemical's concentration in the environment.

Compounds accumulate in living things any time they are taken up and stored faster than

they are broken down (metabolized) or excreted. Heavy metals can enter a water supply

by industrial and consumer waste, or even from acidic rain breaking down soils and

releasing heavy metals into streams, lakes, rivers and groundwater.

Heavy metals in wastewater can be readily absorbed by marine animals and

directly enter the human food chains, thus presenting a high health risk to consumers

(Sheng et al., 2000). Small amounts of these elements are common in our environment

and diet and are actually necessary for good health, but large amounts of any of them

may cause acute or chronic toxicity (poisoning). Heavy metal toxicity can result in

damaged or reduced mental and central nervous function, lower energy levels, and

damage to blood composition, lungs, kidneys, liver and other vital organs (Luthor et al.,

2009). Long-term exposure may result in slowly progressing physical, muscular, and

neurological degenerative processes that mimic Alzheimer's disease, Parkinson's disease,

muscular dystrophy and multiple sclerosis. Allergies are not uncommon and repeated

long-term contact with some metals or their compounds may even cause cancer.

For some heavy metals, toxic levels can be just above the background concentrations naturally found in nature. Heavy metals will not degrade into harmless

end products Thus, treatment of aqueous wastes containing soluble heavy metals

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In this project, we extracted the metal ions by using batch technique. Therefore,

the propose chelating ion exchange resin is the poly(amidoxime) ligands, which is

applied to the removal of target metal ions such as copper, iron, chromium, zinc,

cadmium, lead and arsenic.

1.2 OBJECTIVES OF THE RESEARCH

This experiment had carried out some objectives:

1. To prepare poly(methyl acrylate) grafted kenaf cellulose by chemical

initiating process.

2. To synthesize a novel chelating resin containing hydroxamic acid functional

groups from acrylic polymer grafted kenaf cellulose.

3. To investigate the performance of resin towards wastewater containing toxic

metal ions.

1.3 SCOPE OF THE STUDY

1. The cellulose obtained from local trees and modifying the cellulose and

converted to polymeric chelating ligand.

2. The polymeric chelating ligand could be used to extract metal ions from

industrial waste water and it was found to be highly efficient. Thus, the

polymer chelating ligand can be a suitable material as adsorbent to remove

metals and save the environment.

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1.4 PROBLEM STATEMENTS

Now days, our government take seriously about water pollution because it very

dangerous to ourselves and animal. Heavy metal do not degrade easily into harmless end

products and due to their high toxicity, industrial wastewater containing heavy metals

must be treated before being discharged in the environment. A large environment, public

health and economic impact are evident due to the toxic metals entering into the

environment. Heavy metals contamination in aqueous wastes from many industries such

as metal plating, mining operation, tanneries, chioroalkali, radiator manufacturing,

smelting, alloy industries and storage batteries industries.

Removal heavy metal ions from wastewater need much attention and we have been

focused on the use of cellulose as low cost adsorbents to remove heavy metal ions from

contaminated waters. Spent cellulose, an abundantly available material that is currently

disposed of as a solid waste, are potentially suitable for such applications. Besides that,

most of these living plant investigated so far have limitations in terms of efficiency and

their adsorption capacities for heavy metals. The limitations of some of the

aforementioned technologies which include high cost, unavailability, generation of large

volumes of secondary waste and poor removal efficiency has necessitated the continued

search for new adsorbent materials.

The removal percentage of heavy metal is crucial. Because some heavy metal

compounds still contain in waste water. In addition, the management of the heavy metal

and concentrated contaminants present in the sludge is still one of the most difficult and

vital problems in the field of wastewater effluent. So that, a sustainable treatment is

necessary for remove heavy metal from wastewater and protect the environment.

Immediate concerns with ligands, includes the weak nonspecific binding abilities

for heavy metals. The polymeric chelating ligands in the chains that lack either chain

length or sufficient bonding sites may produce precipitates that are unstable over time

and under certain pH conditions. For this reason, it has been the focus of our research to

design and synthesize better polymeric chelating ligands, which not only bind heavy

metals, but also produce stable precipitates. Stabilizing metal complexes is

accomplished through interaction with metal cations on the ligand.

CHAPTER 2

LITERATURE REVIEW

2.1 Graft Copolymerization

In modern civilization, we must try to replace the natural materials with either all

synthetic materials or modified natural materials. In the polymeric age, it is essential to

modify the properties of a polymer according to tailor-made specifications designed for

target applications. There are several means to modify polymers properties, blending,

grafting and curing. Grafting is a method where in monomers are covalently bonded

(modified) onto the polymer chain, whereas in curing, the polymerization of an oligomer

mixture forms a coating which adheres to the substrate by physical forces. Actually,

there is no time scale for the process of grafting, which can take minutes, hours or even

days.

A polymer comprising molecules in which the main backbone chain of atoms has

attached to it at various points side chains containing different atoms or groups from

those in the main chain. The main chain may be a copolymer or may be derived from a

single monomer. Graft copolymers are prepared by linking two different polymers but

unlike block copolymers, structural sequence is such that one type of polymer is linked

to the other through a branched structure. Based on Starmett et al., 1984, "a graft

Copolymer consists of a polymeric backbone with lateral covalently linked side chains,

both the backbone and side chain polymers can be homopolymers or copolymers.

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The formation of copolymers of various synthetic and natural polymers via graft

copolymerization has been extensively studied. Various monomers such as methyl

acrylate (MA) and methyl methacrylate (MMA) have been graft copolymerized with

numerous polymeric ' backbones using various initiating systems. "A number of reviews

Stannet et al., 1984; Bhattacharyya et al., 1984) were published which differ from each

other in various degrees of detail. Some stressed one method of initiation while others

considered different methods of initiation. However, the bulk of graft copolymerization

studies owe their origin to initiation by free radical initiators. Free radicals are produced

on the starch substrate and then react with the monomers to form the respective graft

copolymers. Free radicals can be produced by a number of methods such as chemical

method, mechanical degradation and low or higher energy irradiation technique. Our

review emphasizes on the chemical initiation method.

a

Figure 2.1: Schematic diagram of argon glow discharge treatment for the immobilization of surfactants.

Source: Stannet et al., 1984; Bhattacharyya et al., 1984

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Cellulose graft copolymers is the general name given to a class of cellulose

derivatives containing polymeric side chains, covalently linked to oxygen of the

glycosidic unit. Since 1950, different olefins have been grafted onto cellulose and starch

(Estella et al., 1998) with the aim of preparing new products having peculiar properties.

Grafting processes used nowadays typically proceed under heterogeneous conditions:

cellulose in the solid state is attacked by a number of chemical agents in order to

undergo free-radical or ionic grafting, the free-radical methods being the most common

ones. Aqueous solutions of peroxides, persulfates and redox systems (e.g. Ce 4 or Fe 2+

/H202) can be used in the initiation step: however, depending on the olefin chemical

nature, other suitable solvents, such as acetic acid, dimethyl sulfoxide, sulfuric acid or

mixed polar solvents, may replace water. The final product, after separation from the

reaction medium, is always a mixture of graft copolymer, unreacted cellulose and olefin

homopolymer, the proportion among the three components depending on the processing

conditions.

2.2 Grafting Initiated by Chemical Means

A method for producing polymer coatings by surface initiated polymerization

from a plasma deposited coating is provided. The modification of surfaces by polymer

attachment is a versatile and efficient means of controlling interfacial properties, such as

surface energy (i.e. wetting behavior), permeability, bio-activity and chemical reactivity.

The present invention provides a method whereby plasma deposited coating is applied to

a substrate and the polymer coating formed by surface initiated polymerization is formed

on the coating rather than the substrate itself. This means that the growth of the polymer

using the grafting from procedure can be performed efficiently and independently of the

substrate from.

Two major types of grafting methods may be considered: (i) grafting with a

single monomer and (ii) grafting with a mixture of two or more monomers. The first

type usually occurs in a single step. While, second step may occur with either the

sunultaileous or sequential use of the two monomers. There are five techniques of