8/17/2019 Samy Reprt 11

1/36

CHAPTER 1

INTRODUCTION

1.1. Overview of composites

The advantage of composite materials over conventional materials stem largel from their 

higher specific strength! stiffness and fatig"e characteristics! #hich ena$les str"ct"ral design to

 $e more versatile% & definition! composite materials consist of t#o or more constit"ents #ith

 phsicall separa$le phases% Ho#ever! onl #hen the composite phase materials have nota$l

different phsical properties it is recogni'ed as $eing a composite material% Composites are

materials that comprise strong load carring material ()no#n as reinforcement* im$edded in#ea)er material ()no#n as matri+*% Reinforcement provides strength and rigidit! helping to

s"pport str"ct"ral load% The matri+ or $inder (organic or inorganic* maintains the position and

orientation of the reinforcement% ,ignificantl! constit"ents of the composites retain their 

individ"al! phsical and chemical properties- et together the prod"ce a com$ination of 

."alities #hich individ"al constit"ents #o"ld $e incapa$le of prod"cing alone% The

reinforcement ma $e platelets! particles or  fi$ers and are "s"all added to improve mechanical

 properties s"ch as stiffness! strength and to"ghness of the matri+ material% /ong fi$ers that are

oriented in the direction of loading offer the most efficient load transfer% This is $eca"se the

stress transfer 'one e+tends onl over a small part of the fi$er0matri+ interface and pert"r$ation

effects at fi$er ends ma $e neglected% In other #ords! the ineffective fi$er length is small%

Pop"lar fi$ers availa$le as contin"o"s filaments for "se in high performance composites are

glass! car$on and aramid fi$ers%

1.2. Types of Composites

or the sa)e of simplicit! ho#ever! composites can $e gro"ped into categories $ased on the

nat"re of the matri+ each tpe possesses% 2ethods of fa$rication also var  according to

 phsical and chemical properties of the matrices and reinforcing fi$ers%

1.2.1 Metal Matrix Composites (MMCs)

1

8/17/2019 Samy Reprt 11

2/36

2etal matri+ composites! as the name implies! have a metal matri+% E+amples of matrices in

s"ch composites incl"de al"mini"m! magnesi"m and titani"m% The tpical fi$er incl"des

car$on and silicon car$ide% 2etals are mainl reinforced to s"it the needs of design% or 

e+ample! the elastic stiffness and strength of metals can $e increased! #hile large co0efficient of 

thermal e+pansion! and thermal and electrical cond"ctivities of metals can $e red"ced $ theaddition of fi$ers s"ch as silicon car$ide%

1.2.2 Ceramic Matrix Composites (CMCs)

Ceramic matri+ composites have ceramic matri+ s"ch as al"mina! calci"m! al"mino silicate

reinforced $ silicon car$ide% The advantages of C2C incl"de high strength! hardness! high

service temperat"re limits for ceramics! chemical inertness and lo# densit% Nat"rall resistant

to high temperat"re! ceramic materials have a tendenc to $ecome $rittle and to fract"re%

Composites s"ccessf"ll made #ith ceramic matrices are reinforced #ith silicon car$ide fi$ers%

These composites offer the same high temperat"re tolerance of s"per allos $"t #itho"t s"ch a

high densit% The $rittle nat"re of ceramics ma)es composite fa$rication diffic"lt% Us"all most

C2C prod"ction proced"res involve starting materials in po#der form% There are fo"r classes

of ceramics matrices3 glass (eas to fa$ricate $eca"se of lo# softening temperat"res! incl"de

 $orosilicate and al"mino silicates*! conventional ceramics (silicon car$ide! silicon nitride!

al"min"m o+ide and 'irconi"m o+ide are f"ll crstalline*! cement and concreted car$on

components%

1.2.3 Polymer Matrix Composites (PMCs)

The most common advanced composites are polmer matri+ composites% These composites

consist of a polmer thermoplastic or thermosetting reinforced $ fi$er (nat"ral car$on or 

 $oron*% These materials can $e fashioned into a variet of shapes and si'es% The provide great

strength and stiffness along #ith resistance to corrosion% The reason for these $eing most

common is their lo# cost! high strength and simple man"fact"ring principles% D"e to the lo#

densit of the constit"ents the polmer composites often sho# e+cellent specific properties%

1.3. Natural Fier Composites

i$er0reinforced polmer composites have plaed a dominant role for a long time in a variet

4

8/17/2019 Samy Reprt 11

3/36

of applications for their high specific strength and mod"l"s% The man"fact"re! "se and

removal of traditional fi$er5reinforced plastic! "s"all made of glass! car$on or aramid fi$ers5 

rein forced thermoplastic and thermoset resins are considered criticall $eca"se of 

environmental pro$lems% & nat"ral fi$er composites #e mean a composite material that is

reinforced #ith fi$ers! particles or platelets from nat"ral or rene#a$le reso"rces! in contrast tofor e+ample car$on or aramide fi$ers that have to $e snthesi'ed% Nat"ral fi$ers incl"de those

made from plant! animal and mineral so"rces% Nat"ral fi$ers can $e classified according to

their origin% The detailed classification is sho#n in ig"re 1%1%

 

Fi!ure 1.1 Classification of nat"ral fi$ers

1.3.1 Animal Fiber

Animal fiber generally comprise proteins; examples mohair, wool, silk, alpaca, angora.

Animal hair (wool or hair) are the fibers taken from animals or hairy mammals. E.g. Sheep’s

wool, goat hair (cashmere, mohair), alpaca hair, horse hair, etc. Silk fibers are the fibers

collected from dried saliva of bugs or insects during the preparation of cocoons. Examples

include silk from silk worms. Avian fibers are the fibers from birds, e.g. feathers and feather

fiber.

1.3.2 Mineral fiber: 

6

Natural Fibers

Plant FibersMineral FibersAnimal Fibers

Seed fiber

Leaf fiber

Skin fiber

Fruit fiber

Stalk fiber

Asbestos

Ceramic fibers

Metal fibers

Animal hair Silk 

fiber

Avian fiber

8/17/2019 Samy Reprt 11

4/36

Mineral fibers are naturally occurring fiber or slightly modified  fiber procured from

minerals. These can be categorized into the following categories: Asbestos is the only naturally

occurring mineral fiber. Varietions are serpentine and amphiboles, anthophyllite. Ceramic

fibers includes glass fibers (Glass wood and Quartz), aluminium oxide, silicon carbide, and

boron carbide. Metal fibers includes aluminium fibers

1.3.3 Pla"t fier

 Plant fi$ers are generall comprised mainl of cell"lose3 e+amples  incl"de cotton! 7"te!

fla+! ramie! sisal and hemp% Cell"lose fi$ers serve in the man"fact"re of paper and cloth% This

fi$er can $e f"rther categori'es into follo#ing as3 ,eed fi$er are the fi$ers collected from the

seed and seed case e%g% cotton and )apo)% /eaf fi$er are the fi$ers collected from the leaves e%g%

sisal and agave% ,)in fi$ers are the fi$ers are collected from the s)in or $ast s"rro"nding the

stem of their respective plant% These fi$ers have higher tensile strength than other fi$ers%

Therefore! these fi$ers are "sed for d"ra$le arn! fa$ric! pac)aging! and paper% ,ome e+amples

are fla+! 7"te! $anana! hemp! and so$ean% r"it fi$er are the fi$ers are collected from the fr"it

of the plant! e%g% cocon"t (coir* fi$er% ,tal) fi$er are the fi$ers are act"all the stal)s of the

 plant% E%g% stra#s of #heat! rice! $arle! and other crops incl"ding $am$oo and grass% Tree

#ood is also s"ch a fi$er%

 Nat"ral fi$er composites are $ no means ne# to man)ind% Alread the ancient Egptians "sed

cla that #as reinforced $ stra# to $"ild #alls% In the $eginning of the 48th cent"r #ood0 or 

cotton fi$er reinforced phenol0 or melamine formaldehde resins #ere fa$ricated and "sed in

electrical applications for their non0cond"ctive and heat0resistant properties% At present animals

or hair mammals% E%g% ,heep9s #ool! goat hair (cashmere! mohair*! alpaca hair! horse hair! etc%

,il) fi$ers are the fi$ers collected from dried saliva of $"gs or insects d"ring the preparation of 

cocoons% E+amples  incl"de sil) from sil) #orms% Avian fi$er are the fi$ers from $irds! e%g%

feathers and feather fi$er%

:

8/17/2019 Samy Reprt 11

5/36

la+ &orneo

;o#ar India! so"th#est Pacific! A"stralia

Areca malasia! India

Ramie Hond"r"s! 2a"riti"s

;"te India! Egpt!

8/17/2019 Samy Reprt 11

6/36

1.#.1 $ute

;"te fi$er (see ig 4* is one of the most important vegeta$le fi$ers "sed for vario"s

applications! $eing characteri'ed $ a long! soft and shin fi$er #hich can $e sp"n into coarsestrong threads% Environment friendl $eing 188? $io0degrada$le! the 7"te fi$er is afforda$le

and can $e $lended #ith other fi$ers! either snthetic or nat"ral%

;"te fi$er presents a high tensile strength! lo# e+tensi$ilit! lo# thermal cond"ctivit and

aco"stic ins"lating properties%

ig 1%4 7"te fi$er 

1.#.2 %emp

Hemp is the name of the soft! d"ra$le fi$er that is c"ltivated from plants of cannabis

 genus for ind"strial and commercial "se% The common application of the hemp fi$er is to $e

 $lend #ith polproplene in a non#oven mat #hich thro"gh compression molding techni."e

t"rns to a three dimensional part%

@hen the hemp #as compared #ith glass fi$er has sho#ed an e."ivalent o"ngBs

mod"l"s! a m"ch lo#er densit and costs (appro+imatel half the price*! and a red"ction in

molding time%

8/17/2019 Samy Reprt 11

7/36

ig 1%6 hemp fi$er 

D"e to its properties the can $e "sed for a"tomotive applications! sporting goods! m"sical

instr"ments! l"ggage! etc%! thro"gh the processes availa$le li)e compression molding! in7ection

molding! and hand la"p or even h$rid technologies%

ig 1%: Application of hemp fi$er 

1.#.3 &e"af  

 

=enaf is an her$aceo"s ann"al plant that can $e gro#n "nder a #ide range of #eather 

condition! for e+ample! it gro#s more than 6m #ithin 6 months even in moderate am$ient

condition%

1%> =enaf fi$er

The interest in c"ltivate )enaf is d"e to its potential to a$sor$ nitrogen and phosphor"s incl"ded

in the soil and also $ the potential in assimilate a significant rate of car$on dio+ide%

8/17/2019 Samy Reprt 11

8/36

=enaf e+hi$its lo# densit! non0a$rasiveness d"ring processing! high specific mechanical

 properties and $iodegrada$ilit% It can $e "sed as a domestic s"ppl of cordage fi$er in

man"fact"re of rope! t#ine carpet $ac)ing and $"rlap% In a"tomotive ind"str #or)s as a

s"$stit"te for fi$erglass or other snthetic fi$ers! and can $e fo"nd in a"tomo$ile dash$oards!

carpet padding and corr"gated medi"m%The main processes $ #hich the fi$er and matri+ cant"rn into final prod"ct are in7ection molding and e+tr"sion%

1.#.# 'reca

The Areca h"s) is availa$le in large ."antities as resid"e from areca prod"ction in man

areas! #hich is ielding the coarse areca fi$er% Among all the nat"ral fi$er0reinforcing

materials! areca appears to $e a promising material $eca"se it is ine+pensive! availa$ilit is

a$"ndant and a ver high potential perennial crop% It $elongs to the species Areca catech" /%!

"nder the famil palmecea and originated in the 2alaa penins"lar! East India% 2a7or ind"strial

c"ltivation is in East India and other co"ntries in Asia% In India! areca n"t c"ltivation is coming

"p on a large scale $asis #ith a vie# to attaining self s"fficienc in medicine! paint! chocolate!

to :%? of 

hemicell"loses! :%:? of ash content and remaining to 4>? of #ater content% The fi$ers

ad7oining the inner laer are irreg"larl lignified gro"p of cells called hard fi$ers and the

 portions of the middle laer contain soft fi$ers% Areca fi$er is highl hemi cell"losic and is

m"ch greater than that of an other fi$ers% Areca has higher lignin content than fi$ers FG

8/17/2019 Samy Reprt 11

9/36

 

Fi! 1. 'reca fire

1.#.* $owar fier

;o#ar fi$er #hich is derived from the species of sorgh"m $icor plant stem% It is gro#n"p #armer climates #orld#ide% ,pecies are native to tropical and s"$tropical regions of all

continents in addition to the so"th#est Pacific and A"stralasia and India%

;o#ar fi$er has a tensile strength of 684 2Pa! mod"l"s of % ? higher 

than sisal and $am$oo% The diameter of the 7o#ar fi$er is 8 Jm to >88 Jm F4G%

 

Fi! 1.+ $owari fier

 

http://en.wikipedia.org/wiki/Australasiahttp://en.wikipedia.org/wiki/Australasia

8/17/2019 Samy Reprt 11

10/36

 1.*. C,emical treatme"t

Cell"lose fi$ers! #hich are strongl polari'ed! are inherentl incompati$le #ith hdropho$ic

 polmers d"e to their hdrophilic nat"re% In man cases! it is possi$le to ind"ce compati$ilit

in t#o incompati$le materials $ introd"cing a third material that has properties intermediate

 $et#een those of the other t#o% There are several co"pling mecha0nisms in materials (e%g%!#ea) $o"ndar laers! deforma$le laers! restrained laers! #etta$ilit! chemical $onding! and

acid5$ase effect*%

The development of a definite theor for the mecha0nism of $onding "sing co"pling agents in

composites is a comple+ pro$lem% The main chemical $onding theor alone is not s"fficient% ,o

the consideration of other concepts appears to $e necessar% These incl"de the morpholog of 

the interphase! the acid5$ase reactions in the interface! s"rface energ and the #etting

 phenomena% Chemical modifications of nat"ral fi$ers aimed at improving the adhesion #ithin

the polmer matri+ "sing different chemicals #ere investigated% There are several chemical

treatment are availa$le li)e al)ali'ation! silane co"pling agent! acetlsation method

1.*.1 -ila"e treatme"t

The s"rface energ of fi$ers is closel related to the hdrophilic nat"re of the fi$er%

,ome investigations are concerned #ith methods to decrease hdrophilicit% ,ilane co"pling

agents ma contri$"te hdrophilic properties to the interface! especiall #hen amino0f"nctional

silanes! s"ch as epo+ies and "rethanes silanes! are "sed as primers for reactive polmers% The

 primer ma s"ppl m"ch more amine f"nctionalit than can possi$l react #ith the resin in the

interphase% Those amines! #hich co"ld not react! are hdrophilic and therefore responsi$le for 

the poor #ater resistance of $onds% An effective #a to "se hdrophilic silanes is to $lend them

#ith hdropho$ic silanes s"ch as pheniltrimetho+silane% 2i+ed silo+ane primers also have an

improved thermal sta$ilit! #hich is tpical for aromatic silicones%

18

8/17/2019 Samy Reprt 11

11/36

1.*.2 'lali"e treatme"t

Al)aline treatment or merceri'ation is one of the most "sed chemical method (removes

a certain amo"nt of lignin! #a+ and oils covering the e+ternal s"rface of the fi$er cell #all* for 

nat"ral fi$ers #hen "sed to reinforce thermoplas0tics and thermosets% The important

modification achieved #ith al)aline treatment is the disr"ption of the hdrogen $onding in thenet#or) str"ct"re! there$ increasing the s"rface ro"ghness

1.*.3 'cetylatio"

Acetlation is another method of modifing the s"rface of nat"ral fi$ers and ma)ing

them more hdropho$ic% It descri$es the introd"ction of an acetl f"nctional gro"p into an

organic compo"nd% The main idea of acetlation is to coat the OH gro"ps of fi$ers #hich are

responsi$le for their hdrophilic character #ith molec"les that have a more hdropho$ic

nat"re%

1.*.# Maleate/ coupli"!

 No#adas! maleated co"pling is #idel "sed to strengthen nat"ral fi$er reinforced

composites% The f"ndamental difference #ith other chemical treatments is that maleic

anhdride is not onl "sed to modif fi$er s"rface $"t also the polmeric matri+ to achieve

 $etter interfacial $onding in $et#een fi$er and matri+ and improved mechanical properties in

composites% There are n"mero"s p"$lished st"dies in #hich the effect of maleic anhdride

grafting on the mechanical properties of nat"ral fi$ers has $een investigated and it is

impossi$le to list all of them here% Hence! onl a fe# representative st"dies are disc"ssed here%

As in composite prod"ct #ith snthetic fi$ers! the drivers for the selection of the appropriate

 process technolog are the same #ith the nat"ral fi$ers% Iss"es li)e the final prod"ct shape!

 performance! cost of the prod"ct and lo# cost of man"fact"re involves! too the nat"ral fi$ers%

,everal factors #hich m"st $e considered in selecting the process are the distri$"tion of the

resin #ithin the fi$ers- the compati$ilit $et#een the hdropho$ic matri+ and hdrophilic

fi$ers- that fi$er attrition is minimi'ed d"e to processing to ens"re reinforcement- that the

moist"re inherent #ithin the fi$er is at the desired level% These factors #ere incl"ded in the

11

8/17/2019 Samy Reprt 11

12/36

 processes presented a$ove as for thermoset process! regarding to the thermoplastic processes

e+tr"sion! in7ection and D0/T are descript% As r"le! the same processes as for snthetic fi$ers

involve the nat"ral fi$ers! #ith some changes incl"ding the dr process of the nat"ral fi$er 

 prior to impregnation%

1.6. Thermoset

The method involves the same $ehavio"r as for an other composite snthetic

reinforcement% &eginning in preparing the mold! appling an eno"gh degree of finishes and

release agent% Then a gel coat consisting of a resin #ith or #itho"t a pigment is applied to the

same mold to g"arant a resin0rich top s"rface% The prepreg is laid on the prepared mold! than

is pressed #ith a hand roller to eliminate the air $"$$les and the e+cess of resin% After c"ring

the prod"ct is s"$7ected to a post 0 c"ring treatment% Thro"gh this process the level in achieving

a fi$re loading is not high! $eing dependent on the post 5 c"re treatment and on the anatomical

feat"res of the nat"ral fi$res% It is mandator for the nat"ral fi$er reinforcement to $e dr in an

oven prior to resin impregnation! to avoid poor #etting and moist"re entrapment in the

composite%

The nat"ral fi$ers that ma $e "sed thro"gh this process #ith resin polester are3 coir 

fi$er! $ananasisal!$anana cotton fa$ric%

1.+. M'N0F'CT0N T4C%N504-

1.+.1 Compressio" mol/i"!

The press"re method is ver pop"lar in the man"fact"re of nat"ral fi$er composites

 $eca"se of its high reprod"ci$ilit and lo# ccle time% The t#o methods in "se are compression

and flo# compression molding% The  processes differ concerning the )ind of semi0finished

 prod"ct "sed and its c"tting% In the compression molding process! flat semi0finished prod"cts or 

h$rid fleeces are "s"all "sed that are either larger than the form or are c"t e+actl to the si'eof the desired part%

14

8/17/2019 Samy Reprt 11

13/36

1.+.2 Filame"t wi"/i"!

In filament #inding the contin"o"s fi$ers are impregnated in a resin mi+ $ath and then

#o"nd on a rotating mandrel% The s"ccessf"l clinders #ith longit"dinal or helical and hoop

reinforcement #ere made #ith sisal epo+ and 7"te0polester%

1.+.3 %a"/ pultrusio"

As is )no#n! p"ltr"sion is a "sef"l techni."e in ma)ing contin"o"s prod"cts for varied

application% Reported $ Ray et al ! the "sed this method to fa$ricate composite rod samples

for e+perimentation% The hollo# glass t"$es #ere "sed as mo"ld% The pre dried fi$re #ere

mi+ed #ith the resin sstem (resin mi+ #ith accelerator! catalst and promoter* and p"lled

thro"gh the glass t"$es $ hand to prod"ce composites in the form of rods%

8/17/2019 Samy Reprt 11

14/36

contin"o"sl fed to a heated cham$er and carried along $ a feed0scre# #ithin% As the solid

resin is conveed! it compressed! melted and forced o"t of the cham$er thro"gh a die% Thro"gh

the cooling process the melt part res"lts in a resolidification of the resin into a piece%

ig 1% E+tr"sion process

In the case of $io0composites! the $asic e+tr"der e."ipment (see ig 14* #or)s the same or had

s"pported fe# modifications%

8/17/2019 Samy Reprt 11

15/36

fi$ers are impregnated #ith resin* and forced o"t thro"gh a die% After cooling process the melt

 part res"lts in a contin"o"s profile%

The e."ipment #hich had s"pported modifications is intended to create ra# materials for the

in7ector% The adaptations #ere made to the feed stoc)er- in fact another feed stoc)er #as added! $eing in this #a g"aranteed the e+actl ."antities of fi$ers inside of $eads or pallets% Other 

tpes of e+tr"ders can incl"de t#in scre#s! #hich can $e co0rotating and co"nter rotating and

 planetar e+tr"ders #hich can incl"de single0scre#% All this adaptations had and achieve the

same goals3 material feed! heat application! dispersing mi+ing! distri$"te mi+ing!

devolatili'ation and material e+tr"sion thro"gh die%

1.+. "6ectio" mol/i"!

In7ection molding is the main process "sed $ man"fact"res for ma)ing

composite prod"cts! #here comple+ shapes are needed in a cclic! high vol"me prod"ction%

The advantages on "sing this process are the e+cellent dimensional tolerance and short ccle

times! co"pled #ith fe# post processing operations%

According to the ;O2 5 Novem$er 488 maga'ine! one of the challenges posed $ in7ection

molding nat"ral fi$ers composites is to prod"ce pellets of a consistent ."alit% This challenge

has $een e+posed $ the North American and E"ropean in7ection molding e."ipment s"ppliers

thro"gh a process called direct long fi$er thermoplastic molding D0/T and is descript on the

follo#ing sentences%K

1.+.+ 789FT

1>

8/17/2019 Samy Reprt 11

16/36

  Direct /ong i$er In7ection or D0/T process consist in a t#in 5scre# e+tr"der #here

ra# polproplene and glass reinforcements are melt res"lting in a molten charge! that is

s"$se."entl compression molded in a cold tool%

Composite Prod"cts Inc% adopted this process to prod"ce polproplene reinforced #ith :8?

nat"ral fi$er! s"ch as3 )enaf! fla+ and nat"ral fi$erglass h$rids% Another compan is Daimler Chrsler A

 

1.: 'pplicatio"s of "atural fier composites

1

8/17/2019 Samy Reprt 11

17/36

The re."irements of light #eight! lo# cost and nevertheless the red"ction of the CO 4 t"rn the

man"fact"res of all the ind"str to pa more attention of the rene#a$le ra# materials% The

"tili'ation of the nat"ral fi$ers offers the potential to replace a large segment of the glass fi$er 

and mineral fillers at a m"ch lo#er cost% Door panels! seat $ac)s! headliners!

Pac)age tras! dash$oards and p"ltr"ded t"$es are made $ nat"ral fi$ers reinforced thermosetor thermoplastic resin in ig 1%11

1%11

E+amples of nat"ral fi$er composite parts

CHAPTER 2

LITERATURE SURVEY

1

8/17/2019 Samy Reprt 11

18/36

This chapter o"tlines some of the recent reports p"$lished in literat"re on mechanical $ehavior 

of nat"ral fi$er $ased polmer composites #ith special emphasis on areca and 7o#ar fi$er 

reinforced polmer composites%

The development of high performance material made from nat"ral reso"rces is

increasing in the #orld% The nat"ral fi$er components ma $e #ood! sisal! hemp! cocon"t!

cotton! )enaf! fla+! 7"te! a$aca! $anana leaf fi$ers! $am$oo! #heat stra# or other fi$ro"s

material% The advantages of nat"ral fi$er composites incl"de light#eight! lo#0energ

 prod"ction! and environmental friendl% The vario"s tpes of fi$er and their properties are

disc"ssed F1G% N% Len)atesh#aran et al F4G investigated mechanical and #ater a$sorption

 properties $ananasisal reinforced h$rid composites%

In the st"d sho# that addition of sisal fi$er in the composite! res"lts in 1? increase in

tensile strength! :? increase in fle+"ral strength and 6>? increase in impact strength% 2oist"re

a$sorption st"d of h$rid composite sho#s the minim"m moist"re "pta)e is $ >83>8 h$rid

composite% Tensile strength and mod"l"s of short! randoml oriented nat"ral fi$er reinforced

h$rid composites #as predicted "sing the R"le of H$rid 2i+t"res (RoH2s* e."ation% It #as

o$served that the RoH2 e."ation predicted tensile properties of h$rid composites are little

higher than e+perimental val"es% 2% &oopalan et al F6G are st"d mechanical and thermal

 properties of 7"te $anana h$rid composites% This st"d sho#s that addition of $anana fi$er in

 7"teepo+ composites of "p to >8? $ #eight res"lts in increasing the mechanical and thermal

 properties and decreasing the moist"re a$sorption propert% A%L% Ratna Prasad and =%2ohan rao

F:G eval"ated mechanical properties of 7o#ar! sisal $am$oo reinforced polester resin% The

res"lts sho# those 7o#ar fi$er composites almost e."al to $am$oo composites and 1% times

higher than sisal fi$er composites%

The fle+"ral strength of 7o#ar fi$er composites :?! 6>? and the fle+"ral mod"l"s 1%14

times! 4%1 times greater than $am$oo and sisal fi$er composites% =e /i" et al F>G st"died the

"ni directional a$aca and $am$oo h$rid composites% This st"d the effects of the

microstr"ct"re of nat"ral fi$er on the transverse thermal cond"ctivit of "nidirectionalcomposite! a$aca and $am$oo fi$ers #ere "nidirectional aligned to fa$ricate epo+ composites

 $ a resin transfer molding (RT2* techni."e% The res"lts indicated that the transverse thermal

cond"ctivit sho#ed t#o tpes of tendencies #ith fi$er content increasing3 increasing for 

 $am$oo fi$er composites! and decreasing for a$aca fi$er composites%

1

8/17/2019 Samy Reprt 11

19/36

The fi$re5matri+ interface is a diff"sion or reaction 'one! in #hich t#o phases are

chemicall andor mechanicall com$ined% Interfacial adhesion plas a predominant part to

characteri'e the mechanical properties of the composites% If there is poor adhesion across the

 phase $o"ndar! then relativel #ea) dispersion of force occ"rs and res"lts in poor mechanical

 properties% or reinforcement of nat"ral fi$re into the matri+! several pro$lems occ"r along theinterface d"e to the presence of hdrophilic hdro+l gro"ps% This hdrophilic nat"re hinders

the effective reaction #ith the matri+% The ma7or pro$lem of nat"ral fi$re composites originate

from the hdrophilic nat"re of the fi$re and hdropho$ic nat"re of the matri+%

The inherent incompati$ilit $et#een these t#o phases res"lts #ea)ening $onding at

the interface% Chemical treatments on reinforcing fi$re can red"ce its hdrophilic tendenc and

th"s improve compati$ilit #ith the matri+ FG% A$aca #as chemicall treated #ith $en'ene

dia'oni"m salt in order to improve in the mechanical properties of the a$aca0PP composites%

&oth ra# and treated a$aca samples #ere "tili'ed for the fa$rication of the composites% The

mechanical properties of the composites prepared from chemicall treated a$aca are fo"nd to

increase s"$stantiall compared to those of "ntreated ones% Tensile strengths of the composites

of $oth ra# and chemicall treated a$aca0PP composites sho#ed a decreasing trend #ith

increasing filler content% Ho#ever! the val"es for the chemicall treated a$aca0PP composites at

all mi+ing ratios are fo"nd to $e higher than that of neat PP FG% Nat"ral fi$ers offer man

advantages over snthetic fi$ers $"t the nota$le disadvantage of nat"ral fi$ers is its hdrophilic

nat"re% D"e to this nat"re an incompati$ilit $et#een the fi$er and matri+ e+ist #hich

decreases the properties of the composite%

This defect can $e overcome $ chemical modification of fi$er s"rface so as to ma)e it

less hdrophilic% In this #or)! al)ali (NaOH* of vario"s concentrations (8%>?! 1?! 4?! >?!

18?! 1>? and 48?* #as "sed to treat the fi$er s"rface and the effect of these concentrations

on the mechanical and visco0elastic $ehavio"r of the composites #ere carried o"t% rom the

e+perimental investigation! it is fo"nd that 1? NaOH treated fi$er reinforced composites

 $ehaves s"periorl than other treated and "ntreated fi$er composite FG% The incorporation of 

nat"ral fi$res s"ch as sisal7"te #ith glass fi$er composites has gained increasing applications

 $oth in man areas of Engineering and Technolog%

The aim of this st"d is to eval"ate mechanical properties s"ch as tensile and fle+"ral

 properties of h$rid glass fi$er0sisal7"te reinforced epo+ composites% The sisal

8/17/2019 Samy Reprt 11

20/36

2Pa% The 7"te

8/17/2019 Samy Reprt 11

21/36

 ,"ita$le ."antit of c"lms of 7o#ar #as collected after c"tting at their $ase from the

harvest% The leaves at the nodes are removed and the ends of the c"lms #ere trimmed% After 

trimming the c"lms #ere tried in shade for period of one #ee)% The node portions are removed

 $ the c"tting and the c"lms #ere separated into pieces of re."ired length% The clindrical

 pieces #hich contain lignin in central portion are made into strips $ peeling them inlongit"dinal direction and the lignin #hich is ver soft incase of 7o#ar removed from them%

The strips #ere )ept in #ater for a period of a$o"t 6h in order to soften them! and s"$7ected to

a mechanical process $ $eating them gentl #ith a plastic mallet in order to loosen and

separate the fi$er%

3.1.2 'reca

Dried areca fr"it h"s) #as collected from 2ett"pallaam agric"lt"ral area! collected

areca h"s) #as soa)ed in #ater for a$o"t five das% The soa)ing process loosens the fi$er!

#hich then can $e e+tracted easil% inall the fi$er #ere #ashed again #ater and dried #ith

room temperat"re for 1: das% The dried fi$ers #ere designated as "ntreated fi$er%

3.2 '9&'9 T4'TM4NT OF F;4-

The dr areca fr"it fi$ers and 7o#ar #ere treated #ith 1?! 4%>? and >? NaOH sol"tion

separatel for a$o"t :> min at room temperat"re% The fi$ers #ere then #ashed #ith fresh #ater 

to ta)e a#a an NaOH stic)ing on the fi$er s"rface% The fi$ers #ere ne"trali'ed #ith 4%>?

HCl sol"tion at room temperat"re% The fi$ers #ere again #ashed in distilled #ater and dried at

room temperat"re for 4: hr%

  3.3 F';C'TON POC4--

Here compression 2olding is "sed for fa$ricate the nat"ral fi$er composites% The $ase

 plate is fi+ed inside the frame for fa$ricate the nat"ral fi$er composites 8? of rein and

remaining nat"ral fi$ers are "sed% The mi+ed resin and hardener is filled in the pattern% The

 prepared nat"ral fi$ers are randoml po"red in the resin accelerator mi+t"re #itho"t an gap%

41

8/17/2019 Samy Reprt 11

22/36

The roller is rolled in the mo"ld% Again the mo"ld is filled in pattern $ ne+t laer and fi$ers

 po"red randoml%

Fi!3.1 Compressio" Mol/i"! Mac,i"e

This process is sim"ltaneo"sl done till the height of the mo"ld 18mm%The lid is fi+ed on the

top of the frame for distri$"te the load evenl on the mo"ld% The set"p is )ept in the dr placefor 4: ho"rs% After 4:ho"rs the mo"ld is ta)e a#a from the pattern! finall the nat"ral fi$er 

composite is fa$ricated

3.# MO097 P4P''TON-

44

8/17/2019 Samy Reprt 11

23/36

  2o"ld "sed in this #or) is made of mild steel 3

8/17/2019 Samy Reprt 11

24/36

3. -P4CM4N P4P''TON

The fa$rication of the vario"s composite materials is carried o"t thro"gh the

compression molding techni."e% ,hort cocon"t coir fi$ers are reinforced #ith epo+ resin! the

lo# temperat"re c"ring polester resin% The polester resin and the are s"pplied $% Three

different tpes of composites have $een fa$ricated #ith three different fi$er lengths s"ch

18mm% Each composite consisting of 68? of fi$er and 8? of polester resin% The mi+ is

stirred man"all to disperse the fi$ers in the matri+% The cast of each composite is c"red "nder 

a press"re of a$o"t 1 2pa for 1 ho"r $efore it removed from the mo"ld% Then this cast is post

c"red in the air for another 4: ho"rs after removing o"t of the mo"ld% ,pecimens of s"ita$le

dimension are c"t "sing a diamond c"tter for mechanical testing% Utmost care has $een ta)en to

maintain "niformit and homogeneit of the composite%

3.+ T4-TN -T'N7'7-

After fa$rication! the test specimens #ere s"$7ected to vario"s mechanical tests as per 

A,T2 standards%

3.+.1 Te"sile test

Tensile testing of specimen prepared according to A,T2 D 686 #as carried o"t! "sing

electronic tensile testing machine #ith cross head speed of 4 mmmin and a ga"ge length of 

188 mm% the specimen #as prepared 4>8 + 4> + 6 mm% The tensile strength and elongation at

the $rea) of the composites #ere calc"lated from the load5displacement c"rve% Three

specimens #ere tested for each set of samples and the mean val"es #ere reported%

3.+.2 Flexural test

The fle+"ral test #as performed $ the three points $ending method according to

A,T2 D 8 "sing the instr"ment! at 4 C #ith :8 M 4? relative h"midit! and cross headspeed of 4 mmmin! ga"ge length >8mm% The specimen is1:8 16 6 mm 6! Three specimens

#ere tested! and the average #as calc"lated% The specimen #as freel s"pported $ a $eam! the

ma+im"m load #as applied in the middle of the specimen! and the fle+"ral mod"l"s is

calc"lated from the slope of the initial portion of the load deflection c"rve%

3.+.3 mpact test

4:

8/17/2019 Samy Reprt 11

25/36

In impact test! the strength of the samples #as meas"red "sing an I'od digital impact

tester according to A,T2 D 4> standards and all test samples #ere notched% The specimen is

> 16 6 mm6! notched- five specimens #ere tested! to determine the impact resistance and

impact strength of composites% The test specimen #as s"pported $ a vertical cantilever $eam

and #as $ro)en $ a single s#ing of a pend"l"m! the pend"l"m stro)e the face of notches! andthe impact resistance and impact strength of short Agave fi$re reinforced epo+ samples at

room temperat"re #ere o$tained%

Process met,o/olo!y

4>

i$er ,eparation from areca h"s) 

and 7o#ar plant

Cleaning the fi$er "sing al)ali

treatment

8/17/2019 Samy Reprt 11

26/36

Ta$le 6%1 Process 2ethodolog

C%'PT4 #

M4C%'NC'9 C%''CT4-TC- OF

COMPO-T4- 4-09T- > 7-C0--ON-

This chapter presents the mechanical properties of the coir fi$er reinforced polester 

composites prepared for this present investigation% Details of processing of these composites

and the tests cond"cted on them have $een descri$ed in the previo"s chapter% The res"lts of 

vario"s characteri'ation tests are reported here% This incl"des eval"ation of tensile strength!

4

1?! 4%>?!>? al)ali treatment

a$rication of Polmer (compression

mo"lding* composites $ased on @t? andaspect ratio

Cond"cting mechanical propert tests of  polmer $ased nat"ral fi$er composites

and some other tests%

8/17/2019 Samy Reprt 11

27/36

fle+"ral strength! impact strength and micro0hardness has $een st"died and disc"ssed% The

interpretation of the res"lts and the comparison among vario"s composite samples are also

 presented%

3.1. T4N-94 POP4T4-

The effect of the al)ali treatment on the tensile performance of the h$rid fi$re5epo+

composites #ith different chemical treaded fi$er #as investigated and the displacements!

engineering stress and strain! tr"e stress and strain! load! tensile mod"l"s #ere determined% It

sho#s the tensile load of the composites ra#! 1? !4%>?! samples gave good res"lts #hen

compared #ith the other samples%

All the c"rves displaed a linear Hoo)e9s la#% The appearance of a load5deflection

c"rve sho#n $et#een tensile fail"re mode and shear fail"re mode forms can $e considered as a

res"lt of a mi+ed fail"re mode% ,"rface modification of the fi$re $ al)ali treatment improved

chemical $onding and helped to #ithstand high tensile load $ the composites made of them%

The sample 4%>? and 1? gave $etter tensile strength% percents increase in tensile load

e+hi$ited $ all the al)ali treated fi$re composite samples co"ld $e related to the enhanced

mechanical interloc)ing of the fi$re and the resin% This res"lt might $e attri$"ted to a chemical

str"ct"re change in the cell"lose that is inherent in the fi$res $eca"se cell"lose molec"lar 

chains in the microfi$rils lose their crstalline str"ct"re locall as a res"lt of the al)ali

treatment% The engineering stress vers"s engineering strain graphs are sho#n in ig :%1 and the

"ltimate tensile strength (UT,* of the ra#! 1?! 4%>?! >? are >%! %14! 14%>! 18%1 2Pa

respectivel% ra# samples #ere fo"nd to sho# poor tensile strength #hen compared to 1? and

4%>? samples% This increment #as attri$"ted to the increased chemical interactions $et#een the

fi$re and the matri+ $eca"se of the al)ali treatment% ,imilarl! the tr"e stress vers"s tr"e strain

#as analsed for h$rid fi$re reinforced composites as sho#n in ig% :%6% The stress5strain

 $ehavio"r of the composite is controlled $ the characteristics of the fi$re and the matri+% It is

#ell )no#n that the fi$re reinforcing effect is most efficient along the fi$re length and #ith the

res"lts o$tained from vario"s sample! the 4%>? fi$re composite has given $etter tr"e stress%

 The 4%>? and 1? samples9 tr"e stress #as thirt percent more than that of ra# and >?

treated fi$er samples% &oth engineering stress and tr"e stress of 4%>? specimen #ere fifteen

 percent more compared to that of 1? and >? treated fi$er composites% The fail"re tensile strain

for all "ntreated fi$re specimens #as fo"nd to increase compared to that of al)ali treatment

4

8/17/2019 Samy Reprt 11

28/36

specimens%% The s"rface of the "ntreated fi$re indicates fi$re matri+ interfacial fail"re follo#ed

 $ fi$re p"ll o"ts from the matri+% The treated fi$re composites ielded higher o"ng9s

mod"l"s than that of the ra# fi$re composites% It indicated that the al)ali treatment removed

some lignin and hemicell"lose from the fi$re s"rface! th"s! the fi$re s"rface area also increased

and also 4%>? treated fi$re sho# $etter interface $et#een the fi$re and the matri+% The tensile properties in a composite depend mainl on fi$re orientation! $"t the

adhesion $et#een the fi$re and the matri+ is also important and it is tr"e for fi$re reinforced

composites%

ig

load vs displacement graph

4

8/17/2019 Samy Reprt 11

29/36

ig:%4 Ultimate tensile strength

ig:%6 Tr"e stress vs Tr"e strain

i$er treatment tensile strength fle+"ral strength fle+"ral mod"l"s impact strength

4

8/17/2019 Samy Reprt 11

30/36

  ? 2Pa 2Pa 11%>

Areca : :%: %: 14%>

A; Ra# fi$er >%> 1% 48% 4%8

A; 1? %14 44%>4 41%: 4%>treated

A; 4%>? 14%> 4:%> 16%446 :%8treated

A; >? 18%1 11%> %16 :%>treated

Ta$le 1 mechanical propert of treated and "ntreated Areca;o#ar h$rid composites

A; 5 Areca and 7o#er fi$er h$rid composites

3.3. Flexural properties

The fle+"ral strength of the al)ali treated and "ntreated h$rid fi$re reinforced epo+

composites plotted as a f"nction of the different fi$re length is sho#n in igs% The fi$re al)ali

treatment had a marginal effect on the fle+"ral load% The 1? and 4%>? samples gave $etter 

res"lts #hen compared to ra# and >? samples as sho#n in ig% :%>% The fle+"ral strength of 

1? samples #as improved $ appro+imatel five percent than that of 4%>? samples%

 The al)ali treated fi$re composite specifies that a $etter contact and the increase in area

of contact $et#een the fi$re and the matri+ are improving the level of adhesion! possi$l $ theincorporation of a mechanical component of adhesion for the matri+5fi$re interfacial strength

as fo"nd in 4%>? treaded fi$ers and epo+ matri+ composites% This indicates that there is

increased area of contact $et#een the fi$re and matri+ and also implies that the minim"m (18

mm* fi$re length enhances the mechanical components of adhesion for the matri+5fi$re

interfacial strength%

The fle+"ral strength #as fo"nd to $e greater for al)ali treated composites% Increased

fi$re5matri+ adhesion provides increased stress transfer $et#een them as earlier reported% or 

al)ali treated fi$re composite! the interfacial friction stress $et#een matri+ and fi$re is higher 

#hen compared to composites #ith "ntreated fi$res% or an al)ali treated fi$re composite! the

chemical $ond $et#een the fi$re and matri+ is s"perior! in t"rn! giving a higher interfacial

stress%

68

8/17/2019 Samy Reprt 11

31/36

The fle+"ral mod"l"s is fo"nd to $e more for al)ali treated composites as ill"strated in

ig%:%%

8/17/2019 Samy Reprt 11

32/36

ig:%> fle+"ral strength

  ig:% fle+"ral 2od"l"s

64

8/17/2019 Samy Reprt 11

33/36

3.#. mpact properties

The impact strength can onl $e improved $ improved the fi$re treatement and $

increasing the friction stress $et#een the fi$re and the matri+% The total energ dissipated in the

composite $efore final fail"re occ"rs is a meas"re of its impact resistance%

2a7or microfail"re mechanisms operating d"ring impact loading of the composite

incl"de initiation and propagation of matri+ crac)ing! fi$re5 matri+ de$onding! and the fi$re

 $rea)age and fi$re p"llo"t% Impact strength of the fi$re reinforced polmeric composites

depends on the nat"re of the fi$re! polmer! and fi$re5matri+ interfacial $onding% It #as clear 

that the short al)ali treated fi$re reinforced epo+ composites perform $etter in impact than the

"ntreated fi$re5epo+ composites (igs%:%*% The notched impact of ra#!1?! 4%>? and >?

materials #as 4! 4%> :%8!and :%> ; respectivel! evidencing increased interfacial $ond e+hi$ited

 $ the al)ali treated fi$re and matri+%

ig:% Impact strength

66

8/17/2019 Samy Reprt 11

34/36

co"clusio"

• Al)ali treatment sho#s improve the interfacial $onding strength and also improve

mechanical properties #hether the added h$rid fi$ers #ith chemical treatment%

And also its indicates t#o fi$ers are separate it #ill sho# higher than h$rid fi$ers%

• In areca #ith epo+ composites sho#s $etter res"lts compare to the areca and 7o#er 

reinforced epo+ matri+ in all mechanical properties

• ;o#ar epo+ composites tensile strength is 14: 2Pa and areca composites alone :

2Pa and areca! 7o#ar h$rid composites are 18%2Pa #hen the 4%>? chemical

treatment is performed% ,o its val"e hiher than h$rid composites%

• ;o#ar epo+ composites fle+t"ral strength is 16: 2pa and areca composites alone

:%: 2Pa and areca 7o#ar h$rid composites are 4:%> 2pa #hen the 4%>? chemical

treatment is performed% H$rid fi$er val"es are lo#er than individ"al fi$er%

• ;o#ar epo+ composites fle+t"ral mod"l"s is %: 2pa and areca composites alone %:

2Pa and areca composites alone :%: 2Pa This fle+"ral 2od"l"s onl $etter res"lts

compare the areca or 7o#ar #ith epo+ reinforced composites% It indicate 48 times more

than areca or 7o#ar #ith epo+ composites%

• Then the impact strength of 7o#ar #ith epo+ composites is 11%> ;! and areca

composites alone 14%> ;! and areca 7o#ar h$rid composites are :%> ; #hen the >?

chemical treatment is performed• This res"lts are sho#s that mechanical properties are h$rid composite is lo#er than

individ"al fi$er composites%

6:

8/17/2019 Samy Reprt 11

35/36

%

References

1% Omar ar")a! Andr'e7 =% &led')ia! Hans0Peter in)! 2ohini ,ain! &iocomposites

reinforced #ith nat"ral fi$ers3 488854818! Progress in Polmer ,cience 6 (4814*

1>>45 1>%

4%  N% Len)atesh#aran ! A% ElaaPer"mal ! A% Alav"deen ! 2% Thir"chitram$alam!

2echanical and #ater a$sorption $ehavio"r of $ananasisal reinforced h$rid

composites! 2aterials and Design 64 (4811* :815:841

6% 2% &oopalan! 2% Niran7anaa! 2%;% Umapath! ,t"d on the mechanical properties andthermal properties of 7"te and $anana fi$er reinforced epo+ h$rid composites!

Composites Part &3 Engineering !Lol"me >1! A"g"st 4816! Pages >:5>

:% A%L% Ratna Prasad! =%2ohan rao! 2echanical properties of nat"ral fi$er reinforced

 polester3 7o#ar! sisal and $am$oo! 2aterial and design 64 (4811* :> 0 :6

5. =e /i"! Hitoshi Ta)agi! Ros")e Os"gi! himao ang! Effect of phsicochemical

str"ct"re of nat"ral fi$er on transverse thermal cond"ctivit of "nidirectionala$aca$am$oo fi$er composites! Composites Part A3 Applied ,cience and

2an"fact"ring Lol"me :6! Iss"e ! A"g"st 4814! Pages 146:514:1

6>

8/17/2019 Samy Reprt 11

36/36

6. 2%2% =a$ir ! H% @ang! =%T% /a"! % Cardona! Chemical treatments on plant0$asednat"ral fi$re reinforced polmer composites3 An overvie#! Composites3 Part & :6

(4814* 46544

% 2d% Re'a"r Rahman! 2d% 2onim"l H"."e! 2d% Na'r"l Islam! 2ah$"$ Hasan!

2echanical properties of polproplene composites reinforced #ith chemicall treated

a$aca! Composites3 Part &

%  N% Len)atesh#aran! A% Elaa Per"mal! D% Ar"ns"ndaranaagamc! i$er s"rfacetreatment and its effect on mechanical and visco0elastic $ehavio"r of $ananaepo+

composite

% 2%Ramesh! =%Palani)"mar! =%Hemachandra Redd! Comparative Eval"ation on

Properties of H$rid