1

CHAPTER 1

INTRODUCTION

Composites are combinations of two /more dissimilar materials to

form a new material with enhanced material properties that are not available

in the individual materials alone. The important constituents of composites

are the reinforced phase, the matrix and the interphase (Bisanda et al 2000).

The reinforcing phase may be present in the form of fibers, sheets or particles

and is embedded in the matrix. The matrix phase is continuous and acts as a

load transfer medium to the reinforced phases. Matrices can be polymers,

metals or ceramics (Maries Idicula 2008). Composites are used in all sectors

of industries like transportation, electronic and computer systems, commercial

appliances, construction industries etc.

1.1 REINFORCEMENT

(i) A Reinforcing constituent provides strength and rigidity

(Aziz and Ansel 2004).

(ii) It also provides certain additional properties like heat

resistance or conduction, resistance to corrosion etc,

(iii) The reinforcement may be fibers, whiskers, particulates and

flakes, they are shown in Figure1.1.

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Figure 1.1 Flow Chart of Reinforcement

1.1.1 Fibers

(i) The word fiber is a Latin word, meaning string or thread like

portions, which form the most important class of

reinforcements (Alvarez et al 2003). Fibers are classified

into

1. Natural fiber and

2. Synthetic fiber

(ii) They are flexible and can be spun / twisted for wearing,

braiding, knotting etc, to make the desired products.

(iii) They constitute cellulose; polymer of glucose bonded to

lignin, with varying amounts of other natural materials

(Bachtiar et al 2009).

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1.1.2 Natural Fibers

Natural fibers are vegetable fibers that are derived from plants and

animals. They have been employed in all the civilizations of the world to meet

basic requirements like clothing, construction materials, storage systems etc.

These fibers offer fabulous advantages like low pollution, bio-degradability,

low density and cost effectiveness (Bismarck et al 2005). Some of the

common natural fibers, family names and their annual production are shown

in Tables 1.1and 1.2 respectively.

Table 1.1 Common Natural Fiber Families and Scientific Name

Type General Name Family Name Scientific Name

Bast Fibers

Hemp Cannabaceae Cannabis sativa

Jute Tiliaceae Corchoruscapsularis

Flax Linaceae Linumusitatissimum

Kenaf Malvaceae Hibiscus cannabinus

Roselle Malvaceae Hibiscus sabdariffa

Ramie Urticaceae Boehmerianivea

Leaf Fibers

Abaka Musaceae Musa textilis

Sisal Agavaceae Agave sisalana

Henequen Agavaceae Agave fourcroydes

Pineapple Bromeliaceae Ananascomosus

Banana Musaceae Musa mannii

Fruit Fibers Coir Arecaceae Cocosnucifera

Seed FibersKapok Bombacaceae Ceibapentandra

Cotton Malvaceae Gossypium arboreum

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Table 1.2 Annual Productions of Natural Fibers and Sources

(Plackett et al 2004)

Fiber type Origin World Production 103 Tons

Coir Fruit 100

Banana Stem 200

Bamboo Stem 10,000

Jute Stem 2,500

Hemp Stem 215

Flax Stem 810

Abaca Leaf 70

Kenaf Stem 770

Roselle Stem 250

Ramie Stem 100

Sisal Leaf 380

Sun Hemp Stem 70

Cotton Lint Fruit 18,500

Wood Stem 1, 750,000

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1.1.2.1 Cotton Fiber

(i) Cotton is a soft, stable fiber that grows around the seeds of

the cotton plant, a shrub native to tropical and subtropical

regions around the world (Botelho et al 2003). The cotton

plant, cotton fiber with seed, cultivated cotton fibers and

cotton thread are shown in Figures 1.2 and 1.5.

(ii) Cotton fiber is the most widely used fiber across the world

(Das K et al 2009).

(iii) Cotton fibres are used to produce a number of textile

products, fishing nets, coffee filters, tents etc.

Figure 1.2 Cotton Plant

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Figure 1.3 Cotton Fiber with Seed

7

Figure 1.4 Cultivated Cotton Fibers

8

Figure 1.5 Threads of Cotton Fiber

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1.1.2.2 Jute Fiber

Jute is a vegetable fiber, which is long and shiny and can be spun

into coarse strong threads. It is obtained from the Stem of two species, viz,

Corchorus Capillaries L (white jute) and C.Uhtoruis L (tosa jute).

White jute is used for making ropes, twines and fabrics. Tosa jute

fiber is softer, silky and stronger than white jute. Jute fibers are hygroscopic

and swell 23% in diameter, 40% in cross-section and 0.06% in length.

Absorption of water modifies the dimensions, and mechanical and electrical

properties. Jute fibers consist of 12-14% lignin, 21-24% hemicellulose, 58-

63% - cellulose and trace amounts of nitrogenous matter, fats, wax and ash

(Cabral et al 2005). The jute plant, extraction of jute fibers, field of jute fibers,

bundle of jute fibers and structure of jute fiber are shown in Figures1.6 -1.10.

The main advantages of jute fibers are:

Renewable

Eco-friendly

Highly stable

Inexpensive

Have low density

Non-abrasive

Have high strength and low elongation

Resistant to fracture

Have Specific strength

Have reduced tool wear

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The disadvantages of jute fibers are that

They are hygroscopic

The Lignin degrades around 200 °C

They are liable to humid climates

They have decreased strength when wet

Figure 1.6 Jute Plant

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Figure 1.7 Extractions of the Jute Fibers from Jute Plant

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Figure 1.8 Field of Jute Fibers

13

Figure 1.9 Threads of Jute Fiber

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Figure 1.10 Structure of the Jute Fiber

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1.1.2.3 Hemp Fiber

Hemp is a bast fiber with long slender primary fibers on the outer

portion of the stalk. Hemp has been produced for thousands of years as a

source of the fiber for paper, cloth and building materials. There are two types

of hemp fibers (Bledzki et al 2004). They are

(i) Primary bast fibers

(ii) Secondary bast fibers

(i) Primary Bast Fiber

These fibers make up approximately 70 % of the fibers. They are

long with a high cellulose and low lignin content.

(ii) Secondary Bast Fibers

Secondary bast fibers make up the remaining 30% of the bast

fibers, with medium length and high lignin content. Hemp fibers are used for

making papers, textiles, biodegradable plastics, and in construction industries.

The hemp plant, cultivated hemp, field of hemp fiber and threads of hemp

fibers are shown in Figures 1.11 and 1.14.

Figure 1.11 Hemp Fibers Plant

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Figure 1.12 Cultivated Hemp Fibers Plant

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Figure 1.13 Field of Hemp Fibers

18

Figure 1.14 Threads of Hemp Fiber

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1.1.2.4 Sisal Fiber

Sisal is a strong, sturdy, tough and tan-colored fibers that is

prepared from the vascular tissue of the sisal plant. This fiber is resistant to

moisture and heat. It is used for making mats, ropes, carpets etc (Cyras et al

2004 and Garcia et al 2006). The Sisal plant, cultivated sisal, field of sisal

fiber and sisal fiber threads are shown in Figures 1.15-1.18.

Figure 1.15 Sisal Plant

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Figure 1.16 Cultivated Sisal Fibers plant

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Figure 1.17 Field of Sisal Fibers

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Figure 1.18 Threads of Sisal Fiber

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1.1.2.5 Banana Fiber

Banana Fiber is obtained from the edible-fruit bearing plant. The

trunk is removed and the brown-green skin is discarded to get a white portion,

which is processed to get fibers (Elanthikkal et al 2010). The fibers extracted

are dried in sun-light to get white fibers. These fibers can be used for making

a number of products like floor mats, table mats, bags, furnishing etc

(Corrales et al 2007). The banana plant, cut into small disk and banana fibers

are displayed in Figures 1.19 - 1.21.

Figure 1.19 Banana Plants

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Figure 1.20 Cut Banana Tree Trunk into Small Disk-Like Bases

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Figure 1.21 Banana Fibers

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1.1.2.6 Coir (Coconut Fiber)

Coir is derived from the tissues surrounding the seed of the coconut

palm. Coir is strong, light and can withstand heat. Coir is classified into two

types. They are brown fiber and white fibers. Brown fibers are obtained from

mature coconuts, whereas white fibers are extracted from immature green

coconuts (CNF 2009 Islam et al 2010). The coconut tree, coconut fiber with

shell, coconut fibers and coconut ropes are shown in Figures 1.22 - 1.25.

Brown coir is utilised for producing doormats, packaging

applications, brushes, etc (Brahmakumar et al 2005 and Haque et al 2009).

White coir is used for making ropes, fishing nets, decorative items etc.

Figure 1.22 Coconut Tree

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Figure 1.23 Coconut Fibers with Shell

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Figure 1.24 Coconut Fibers

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Figure 1.25 Ropes of Coconut Fiber

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1.1.2.7 Flax Fiber

Flax fiber is extracted from the skin of the flax plant. These fibers

are soft, strong, flexible and lustrous. It is used for preparing high quality

paper, paper for tea bags and packing cigarettes. Apart from the above

applications, it is also used in the production of linen, canvas, ropes and sacks

(Cao et al 2007). The flax plant, cultivated flax, field of flax and flax fiber is

shown in Figures 1.26 - 1.29.

Figure 1.26 Flax Plants

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Figure 1.27 Cultivated Flax Fibers Plant

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Figure 1.28 Field of Flax Fibers Plant

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Figure 1.29 Threads of Flax Fiber

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1.1.3 Chemical Composition of Natural Fibers

Natural fibers are composed mainly of cellulose, hemicellulose,

lignin and pectin. These constituents are widely distributed throughout the

fiber wall, and depend upon the place of origin, production area and variety

(Das et al 2010 and Josep et al 2002).

1.1.4 Chemical Treatment of Natural Fibers

A better understanding of the chemical composition and surface

adhesive bonding of natural fiber is necessary for developing natural fiber

reinforced composites (Islam et al 2009). The interfacial bonding between the

reinforcing fibers and the resin matrix is an important element for improving

the mechanical properties of the composites. Realizing this, several authors

(Ray et al 2001) have focused their studies on the treatment of fibers to

improve the bonding with the resin matrix (Deng et al 2010). The mechanical

properties of the composites are controlled by the properties and quantities of

the individual component and by the character of the interfacial region

between the matrix and the reinforcement. Lack of good interfacial adhesion

makes the use of cellular fiber composites less attractive (Ismail et al 2002).

Often the interfacial properties between the fiber and polymer matrix are low,

because of the hydrophilic nature of natural fiber which reduces its potential

of being used as reinforcing agents. Hence, chemical modifications are

considered to optimize the interface of fibers. Chemicals may activate

hydroxyl groups or introduce new moieties that can effectively interlock with

the matrix. There are various chemical treatments available for the fiber

surface modification (Doan et al 2004). Chemical treatments including alkali,

silane, acetylation, benzoylation, acrylation, isocynates, maleated coupling

agents (Doan et al 2005), permanganate treatment, which are discussed in

detail.

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1.1.4.1 Alkaline Treatment

Alkaline treatment is done on natural fibers to disrupt the hydrogen

bond in the network structure resulting in increased surface roughness.

Certain amounts of lignin, wax and oil, covering the outer surface of the fiber

cell wall are eliminated by this treatment (Gassan and Bledzki 1999). Apart

from this, it depolymerizes the cellulose and promotes the ionization of the

hydroxyl group to the alkoxide. The reaction of alkali treatment with fiber is

shown in Figure 1.30.

Figure 1. 30 Reaction of Alkali Treatment with Fiber

1.1.4.2 Acetylation of Natural Fiber

Acetylation causes the plasticization of cellulose fibers. The

reaction generates acetic acid as a by-product, which should be eliminated

before further use (Haque et al 2010 and Herrera et al 2005). Acetylation

decreases the hygroscopic nature of the natural fiber, and therefore, it can be

well accommodated in the fiber reinforced composites. The reaction of

acetylation treatment with fiber is shown in Figure 1.31.

Figure 1.31 Reaction of Acetylation Treatment with Fiber

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1.1.4.3 Permanganate Treatment

Permanganate treatments are done by using various concentrations

of the KMnO4 solution. This treatment decreases the hydrophilic nature of

the fibers, and therefore, reduces the water absorption behavior of the

composite prepared by these fibers. The reaction of permanganate treatment

with fiber is shown in Figure 1.32. (Joseph et al 2003 and Kamakar et al

2007).

Figure 1.32 Reaction of Permanganate Treatment with Fiber

1.2 MATRIX MATERIAL

When they are in a fibrous form many materials exhibit very good

strength properties, but to achieve these properties the fiber should be bonded

in a suitable matrix. The matrix isolates the fibers from one another, in order

to prevent abrasion and formation of new surface flaws, and acts as a bridge

to hold the fibers in place. A good matrix should possess the ability to deform

easily under applied load, transfer the load on to the fibers and evenly

distribute the stress concentration. A study of the nature of the bonding forces

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in laminates indicates, that upon initial loading there is a tendency for the

adhesive bond between them, that accounts for the high strength properties of

the laminates. The polymer matrix binds the fibers (Klaus et al 2012 and

Klemm et al 2011). They are thermoplastics and thermosetting. The

classification of matrices is shown in Figure 1.33.

Figure 1.33 Classifications of Matrices

1.2.1 Polymer Matrix Material

Polymer matrices are considered as an ideal material since they can

be easily processed, possess light weight and contribute good mechanical

properties. There are two kinds of polymer materials, namely thermoplastic

polymer and thermoset polymer (Ku et al 2011). The classification of polymer

matrix materials is shown in Figure 1.34.

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Figure 1.34 Classifications of Polymer Matrix Materials

1.2.1.1 Thermoplastics

Thermoplastic matrix materials have one or two dimensional

molecular structure and tend to soften at an elevated temperature, and roll

back their properties during cooling (Brostow and Lobland 2006). The best

examples of this kind are polyethylene, polypropylene, polystyrene, nylons,

polycarbonate, polyacetals, polyamide-imides, polyether, ether ketone,

polysulfone, polyphenylene sulfide, polyether imide etc (Brydson 1999).

1.2.1.2 Thermosetting

Thermoset matrix materials have a well bonded 3-d molecular

structure. They decompose instead of melting on hardening (Generi and Vasu

2000). The examples are epoxides, polyesters, phenolics, ureas, melamine,

silicone and polyimides.

1.2.2 Epoxy

Epoxy resins were first used in composites for application in the

early 1950s. This family of oxirane containing polymers can be made from a

wide range of starting components, and provide a broad spectrum of

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properties. Their good adhesion characteristics with glass, aramid and carbon

fibers have resulted in remarkable success as matrix materials for fiber

composites. They also have a good balance of physical, mechanical and

electrical properties and have a lower degree of cure shrinkage than other

thermosetting resins, such as polyester and vinyl ester resins (Lu et al 2006).

Other attractive features for composite application are relatively good hot wet

strength, chemical resistance, dimensional stability, and ease of processing

and low cost (Nishino and Arimoto et al 2005). Epoxy resins are

characterized by the existence of the epoxy group which is a three membered

ring with two carbon atoms and one oxygen. Epoxy resins (Figure 1.35) can

be classified into six different types:

i) Bisphenol A based glycidyl esters

ii) Glycidal ether

iii) Glycidal amines

iv) Novolacs

v) Brominated resins

vi) Cycloaliphatic

Figure 1.35 Structure of Epoxy Resin

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1.3 INTERFACE

The interface is a bounding zone where a discontinuity occurs,

physical, mechanical and chemical. Fibers are wetted by the matrix and to

increase the wettability coupling agents are added. Well “wetted” fibers

increase the interface surfaces area. To obtain the desirable properties in a

composite, the applied load should be effectively transferred from the matrix

to the fibers via the interface (George et al 2001 and Ghosh 2004). This

means that the interface must be large and exhibit strong adhesion between

the fibers and the matrix. Failure at the interface (called de-bonding) may or

may not be desirable (Chitta Rajan 2010).

1.4 CLASSIFICATION OF COMPOSITES

1.4.1 Based on Matrix Material

Based on the matrix materials composites can be classified into

three types. They are

1. Polymer Matrix Composites (PMC)

2. Metal Matrix Composites ( MMC)

3. Ceramic Matrix Composites ( CMC)

1.4.1.1 Polymer Matrix Composites (PMC)

A Polymer matrix composite (PMC) consists of a polymer matrix

combined with a fibrous/particulate reinforcing phase. PMCs are very popular

due to their low cost and simple fabrication methods.

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PMCs are the most developed composite material group, and have

found widespread applications across the globe. The PMC can be easily

fabricated into large complex shape (Generi and Vasu 2000).

The most common polymers employed for PMC are polyester,

vinylester, epoxy, phenolic, polyimmido, polyamido, polypropylene and

others. The reinforcement materials are often fibers and grounded materials.

1.4.1.2 Metal Matrix Composites (MMC)

Metals are durable materials, and have been widely exploited

across the world. When metals are combined with reinforcements such as B,

C, Al2O3, SiC etc, to get metal matrices composites. MMCs are light in

weight, exhibit good stiffness and low specific weight. Apart from these they

also have excellent properties, they have good fracture toughness, thermal

stability, ductility, and increased elevated temperature tolerance.

1.4.1.3 Ceramic Matrix Composites (CMC)

Ceramics are chemically stable and crystalline materials. They are

made by the action of heating and subsequent cooling, from compounds of

metallic or non-metallic elements. Ceramic matrix composites are prepared

by combining a ceramic matrix with suitable fibers such as poly crystalline/

amorphous inorganic fibers/ carbon fibers. Thermosetting and thermoplastics

materials can withstand temperatures upto 300 °C while metals and alloys can

be utilized upto 900 °

C. Above all materials ceramics can withstand

temperatures above 1500° C. Therefore this clearly indicates that ceramics are

the only material which can be used upto 1500 °C ( Nishino and Kotera 2003).

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The most commonly employed ceramic matrix materials include

glass-ceramics and ceramics such as carbon, SiC, silicon nitride, aluminides

and oxides.

1.4.2 Classification of Composites Based on Reinforcement Material

As the word indicates, it provides the strength that makes the

composite what it is. But they also serve certain additional purposes like heat

resistance or conduction, resistance to corrosion and provide rigidity.

Reinforcement can be made to perform all or one of these functions as per the

requirements (Nishino et al 2004).

A reinforcement that embellishes the matrix strength must be

stronger and stiffer than the matrix and should be capable of changing the

failure mechanism of the composite (Srinivasan 2009).

1.4.2.1 Fiber Reinforced Composites

In fiber reinforced composites fiber serves as the reinforced/

dispersed phase. The fiber generally occupies 30% to 70% of the matrix

volume in the composites. The fibers may be in the chopped form or woven

(Figure 1.36). To enhance the bonding between the fiber and matrix they are

treated with starch, gelatin, oil or wax. The most common natural fibers used

for the fabrication composites are jute, hemp, banana, flax, cotton etc, for

advanced composite material, glass fibers, aramid carbon etc are utilized

(Mwaikambo and Ansell 2002). The continuous and short fiber is shown in

Figure 1.37.

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Figure 1.36 Aligned, Random and Woven Fibers

Figure 1.37 Continuous and Short Fibers

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1.4.2.2 Particulates Reinforced Composites

Particulates are uniformly dispersed in a softer ductile matrix. The

particulates provide desirable material properties. Particulate reinforced

composites offer several advantages and are usually produced by injection

moulding technique (Orts et al 2005). Particle reinforced composites (Figure

1.38) are classified into a) Large particle composites and b) Dispersion

strengthened composites.

a) Large Particle Composites:

Large particle composites consist of large sized particles embedded

in a relatively soft matrix. The matrix and the reinforced particles share the

load. A typical example is concrete.

b) Dispersion Strengthened Composites:

Dispersion strengthened composites contains extremely small sized

particles in the range of 10-100 nm. These particles increase the particle-

matrix interactions at the atomic level thereby enhancing the strength of

matrix against deformation.

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Figure 1.38 Particle reinforced composites

1.4.2.3 Laminates

Laminate composites are consists of layers of materials which are

held together by matrix. These layers are arranged alternative fashion for the

better bonding between reinforcement and the matrix. These laminates can

have uni-directional or bi-directional orientation of the fiber reinforcement

according to the application of the composite (Mao et al 2010 and Metha et al

2005). The different types of composite laminates are unidirectional, angle-

ply, cross-ply and symmetric laminates.

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1.5 LITERATURE SURVEY

1.5.1 Jute Fiber Reinforced Composites

Boopalan et al (2012) compared the mechanical properties of jute

and sisal fiber reinforced polymer composites, and found that the jute fiber

reinforced composites possessed good mechanical properties than sisal fiber

reinforced composites.

Kabir et al (2010) studied the effect of benzenediazonium salt in

alkaline medium on the mechanical properties of jute fiber reinforced

polypropylene composites. Except elongation all the mechanical properties

were found to be exceptionally good than the raw jute polypropylene

composites. The elongation at break of treated jute polypropylene composite

decreased to a large extent as compared to that of polypropylene.

Rout et al (2011) investigated the effect of the addition of surface

modified jute fiber on the mechanical properties of polyester. Significant

improvement in tensile properties was observed in the case of alkali treated

composites whereas better flexural strength was observed in the case of

bleached jute-polyester composites.

Alves (2010) reported the effects of the jute fiber treatments on the

mechanical performance of the composite materials. The surface of the jute

fibers was modified by drying and bleaching/drying treatments to improve the

wetting behavior of the polar polyester, improving the mechanical properties

of the composites. Finally, jute composites were compared with glass

composites and results show that the jute fiber treatments imply a significant

increase of the mechanical properties of the composites without damaging

their environmental performances.

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The effect of coupling agent on abrasive wear behaviour of

chopped jute fiber-reinforced polypropylene composites was studied by Navin

Chand (2006). The use of coupling agent gave better wear resistance as

compared to without the use of coupling agent.

Mubarak A. Khan et al (2001) performed the effect of

pretreatment with UV radiation on physical and mechanical properties of

photo cured jute yarn with 1, 6-hexanediol diacrylate (HDDA). UV radiation

pretreatment improved the mechanical properties. The tensile strength and

modulus increased upto 84% and 132% respectively than that of virgin, jute

yarn. An experiment involving water absorption capacity shows that water

uptake by treated samples was much lower than that of the untreated samples.

During the weathering test, treated yarns exhibited less loss of mechanical

properties than untreated yarns.

Rana and Jayachandran (2001) investigated the role of jute

composite as wood substitute. The different methods of jute composite

manufacture with its potentials and prospects are also described.

The processing and characterization of short-fiber reinforced

jute/poly butylene succinate biodegradable composites was studied by Ishiaku

(2006). The results revealed that elongation at break and toughness are most

sensitive to the presence of the weld-line whereas flexural properties are least

sensitive.

Moisture absorption, tensile strength and microstructure evolution

of short jute fiber/polylactide composite in hygrothermal environment was

studied by Rui-Hua Hu (2010). The results reveal that the moisture absorption

and aging process can be effectively retarded by coating. The molecular

weight measurement by gel permeation chromatography (GPC) indicated that

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the PLA matrix was severely degraded in hygrothermal environment. Tensile

strength severely decreased after aging.

Sahari et al (2011) reported the natural fiber reinforced

biodegradable polymer composites. These materials have the capability to

fully degrade and compatible with the environment.

Saha et al (2010) reported the jute fiber reinforced polyester

composites by dynamic mechanical analysis. It is also observed that

incorporation of jute fiber (both unmodified and modified) with the

unsaturated resin reduced the tan peak height remarkably.

Sridhar et al (2011) reported the mechanical properties of jute polyester

composites. The tensile, flexural and impact properties of unidirectional and

bidirectional laminates of jute fiber-polyester composites and the mechanical

properties of glass-jute-polyester composites are reported. The effects of

lignin coated bidirectional jute fiber reinforcement composites gives better

mechanical properties than uni directional jute fiber reinforced composites.

ChandanDatta et al (2012) reported that the mechanical and

dynamic mechanical properties of jute fibers–Novolac–epoxy composite

laminates. It was found that jute fiber reinforced composite using Novolac-

epoxy resins exhibit increased stiffness without sacrificing their ductility.

JochenGassan, and Andrzej K. Bledzki (2004)dipictedthe effect of

moisture content on the properties of silanized jute-epoxy composites. The

introduction of the coupling agent distinctly influences the mechanical

properties of the composite: Dynamic modulus was doubled, damping was

reduced by about 50%, and the Wöhler curves showed fatigue limits increased

by about 20%. The investigations pointed out further that the moisture uptake

of composites with silanized fibers was reduced by about 10–20%. Moisture

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at equilibrium and kinetics of absorption increase with increasing fiber

content. Finally, the application of the coupling agent caused a reduction of

moisture effects on the mechanical properties. Tensile strength, tensile

modulus, and fatigue strength under repeated tensile stress were reduced up to

30%. This tendency was not duplicated in the results for flexural strength and

flexural modulus.

Joshi et al (2001) compared life cycle environmental performance

of natural fiber composites with glass fiber reinforced composites and found

that natural fiber composites are environmentally superior in the specific

applications studied.

Shah and Lakkad (2008) compared the mechanical properties of

jute-reinforced and glass-reinforced composites. The results shows that the

jute fibers, when introduced into the resin matrix as reinforcement,

considerably improve the mechanical properties, but the improvement is

much lower than that obtained by introduction of glass and other high

performance fibers. Hence, the jute fibers can be used as reinforcement where

modest strength and modulus are required. Another potential use for the jute

fibers is that, it can be used as filler, fiber, replacing the glass as well as the

resin in a filament wound component. The main problem in this work is that

it is difficult to introduce a large quantity of jute fibers into the JRP laminates

because the jute fibers, unlike glass fibers, soak up large amount of resin. This

problem is partly overcome when hybridsing with glass fibers is carried out.

Jute fibers were subjected to alkali treatment with 5% NaOH

solution for 0, 2, 4, 6 and 8 h at 30 °C by Ray et al (2009). The fibers after

treatment were find, having less hemicellulose content, increased crystallinity,

reduced amount of defects resulting in superior bonding with the vinylester

resin.

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Jute fibers were treated with alkali (NaOH) solution (Sahaet al

2010). The treatments were applied under ambient and elevated temperatures

at high pressure steaming conditions. The results indicated that the uniaxial

tensile strength increased up to 65% for alkali-steam treatment. The

treatments without steaming were not as effective as Physico-chemical

characterization of fibers showed that the increase in tensile strength was due

to the removal of non-cellulosic matters like lignin, pectin and hemicellulose.

Jawaid et al (2011) studied the chemical resistance, void content

and tensile properties of oil palm/jute fiber reinforced polymer hybrid

composites. It is found from the chemical resistance test that all the

composites are resistant to various chemicals. It was observed that marked

reduction in void content of hybrid composites in different layering pattern.

From the different layering pattern, the tensile properties were slightly higher

for the composite having jute as skin and oil palm EFB as core material.

Effect of fabric treatment and filler content on jute polyester

composites was done by Kanakasabai et al (2007). It was observed that due to

fabric treatment, the mechanical properties were improved significantly.

Alkali treatment was found to reduce moisture absorption and the effect of

calcium carbonate on the mechanical performance of the composite is not

significant.

Wang et al (2009) reported the preparation and characterization of

micro and nano fibrils from jute. This technique includes chemical (room

temperature alkaline, acid steam, and 80 °C alkaline) and physical (high

pressure steam) treatments of natural fibers. The effects of chemical and

physical treatments on the morphological development of jute fibers from

micro-to nano-scale were observed by using scanning electron microscopy

(SEM). Two advantages were found. One is the long strands of natural fibers

keep their length by special acid steam treatment, but the traditional acid

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solution treatment makes the length of natural fibers short. Another one is the

high pressure steam treatment that made jute fibers nano-fibrils.

Bhatnagar and Sain (2009) reported the processing of cellulose

nano fiber-reinforced composites. Cellulose nano fibers are obtained from

various sources such as flax bast fibers, hemp fibers, kraft pulp, jute and

rutabaga, by chemical treatments followed by innovative mechanical

techniques. The nano fibers thus obtained have diameters between 5 and 60

nm. The ultrastructure of cellulose nano fibers is investigated by atomic force

microscopy (AFM) and transmission electron microscopy (TEM). The

cellulose nano fibers are characterized in terms of crystallinity. Reinforced

composite films comprising 90% polyvinyl alcohol and 10% nano fibers are

also prepared. The comparison of the mechanical properties of these

composites with those of pure PVA confirmed the superiority of the former.

The Jute as raw material for the preparation of microcrystalline

cellulose performed by Sarwar Jahan (2010). Cellulose was extracted at a

yield of 59.8% from jute fibers based on the formic acid/peroxy formic acid

process at an atmospheric pressure. The amounts of dissolved lignin and

hemicelluloses were determined in the spent liquor. The results showed that

the spent liquor contained 10.6% total sugars and 10.9% lignin (based on

jute). Microcrystalline cellulose (MCC) was further prepared from the jute

cellulose based on the acid hydrolysis technique. A very high yield, 48–52.8%

(based on the jute raw material) was obtained.

Das (2011) reported the physico-mechanical properties of the jute

micro/nanofibril reinforced starch/polyvinyl alcohol biocomposite films. Jute

micro/nanofibrils (JNF) were prepared from jute by acid hydrolysis route.

Starch/polyvinyl alcohol (PVA) based biocomposite films reinforced with

JNF at different loading of 5, 10 and 15 wt.% were prepared by solution

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casting method, incorporating glycerol as a plasticizer. The 10 wt.% JNF

loaded films exhibited best combination of properties.

1.6 SCOPE AND OBJECTIVES

1) To prepare the nano jute fibers from jute fiber

2) To characterize the nano jute fiber by FTIR and SEM

analysis

3) To fabricate various wt. % of (1%, 2%, 3%, 4%, 5%, 6%, 7%,

8 %) raw jute fiber reinforced epoxy polymer composites

4) To fabricate various wt. % of (1%, 2%, 3%, 4%, 5%, 6%, 7%,

8 %) nano jute fiber reinforced epoxy polymer composites

5) To evaluate the mechanical properties (Tensile, Flexural,

Impact and Hardness) of the prepared composites samples

6) To evaluate the dynamic mechanical analysis (DMA), thermo

gravimetric analysis (TGA), heat deflection temperature

(HDT)

7) To evaluate the water absorption studies

8) To characterize the composites samples by TEM, AFM, and

X-Ray Diffraction

9) To compare the raw jute fiber and nano jute fiber reinforced

epoxy polymer composites