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STUDY THE EFFECT OF ACIDS AND BASES ON THE TENSILE STRENGTH OF A FIBRE. A Project Report Submitted by
HYDER QAID JOHAR In partial fulllment of the
CBSE GRADE XI - B IN Chemistry AT
INDIAN PUBLIC SC!!L R!LL N!"-11#1$ #%1&-1'
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B!NA(IDE CERTI(ICATE This is to ceti!" that HAIDER #HO#HA$ALA o! Ga%e &I'B( INDIAN PUBLIC SHOOL )ith Ro** N+,-e / has co,0i*e% this Che,ist" 0o1ect i2 0atia* !+*3**,e2t o! the e4+ie,e2ts as 0esci-e% -" CBSE i2 the "ea 567'8.
Sig2at+e o! the Teache I2'chage
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AC*N!+LEDGE,ENT I )a,*" ac92o)*e%ge the co2ti2+o+s e2co+age,e2t a2% ti,e*" s+ggestio2s o:ee% -" o+ %ea Pi2ci0a* ;.#.A.Ro%ig+es. I e
," *a- teache ;s. J+*ie sa, !o the co2sta2t s+0e=isio2( 0o=i%i2g 2ecessa" i2!o,atio2 a2% s+00oti2g i2 co,0*eti2g the 0o1ect. I )o+*% *i9e to e<0ess ," gatit+%e to)a%s the, !o thei 9i2% co'o0eatio2 a2% e2co+age,e2t. Fi2a**" I e
Sig2at+e o! the Ca2%i%ate
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INDEX SN! NA,E
RE,AR *
P. No #
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BONAFIDE CARTIFICATE. AC#NO$LEDG;ENT.
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INTRODUCTION.
/-&
1
$
THEORY
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'-0
/
AI;
&
APPARATUS REQUIRED
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'
PROCEDURE.
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0
OBSER?ATIONS
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CONCLUSION.
1)
1%
PRECAUTIONS
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BIBLIOGRAPHY
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INTR!DUCTI!N Fi-e is a c*ass o! ,ateia*s that ae co2ti2+o+s 3*a,e2ts o ae i2 %iscete e*o2gate% 0ieces( si,i*a to *e2gths o! thea%. A 3-e is a2 e*o2gate% ta0ei2g thic9')a**e% 0*a2t ce** that i,0ats e*asticit"( @e
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3-e !o, )hich the" )ee oigi2a**" ,a%e 2ea*" a** ca2 -e ,a%e 2o) )ith othe 3-es( eithe 2at+a* o s"2thetic.The" ae =e" i,0ota2t i2 the -io*og" o! -oth 0*a2ts a2% a2i,a*s( !o ho*%i2g tiss+es togethe. H+,a2 +ses !o 3-es ae %i=ese. The" ca2 -e s0+2 i2to 3*a,e2ts( sti2g( o o0e( +se% as a co,0o2e2t o! co,0osite ,ateia*s( o ,atte% i2to sheets to ,a9e 0o%+cts s+ch as 0a0e o !e*t. Fi-es ae o!te2 +se% i2 the ,a2+!act+e o! othe ,ateia*s. The sto2gest e2gi2eei2g ,ateia*s ae ge2ea**" ,a%e as 3-es( !o e
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-e2e3ts (s+ch as co,!ot (o=e thei s"2thetic co+2te0ats.
THEORY Depending upon the source, various fibres can be categorized as: 1. Animal fibre(e.g., silk and wool) . !egetable fibre(e.g., cotton and linen) ". #$nthetic fibre(e.g., n$lon and ra$on) %atural fibres can be classified according to their origin. &he vegetable, or cellulose'base, class includes such important fibres as cotton, fla, and jute; the animal, or protein'base, fibres include wool,mohair, and silk an important fibre in the mineral class is asbestos. &he vegetable fibres can be divided into smaller groups, based on their origin within the plant. Cotton, kapok , and coir are eamples of fibres originating as hairs borne on the seeds or inner walls of the fruit, where each fibre consists of a single, long, narrow cell. Flax, hemp, jute, and ramie are bast fibres, occurring in the inner bast tissue of certain plant stems and made up of overlapping cells. Abaca, heneuen, and sisal are fibres occurring as part of the fibro vascular s$stem of the leaves. *hemicall$, all vegetable fibres consist mainl$ of cellulose,
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although the$ also contain var$ing amounts of such substances as hemicellulose, lignin, pectins, and waes that must be removed or reduced b$ processing. &he animal fibres consist eclusivel$ of proteins and, with the eception of silk, constitute the furor hair that serves as the protective epidermal covering of animals. #ilk filaments are etruded b$ the larvae of moths and are used to spin their cocoons. +ith the eception of mineral fibres, all natural fibres have an affinit$ for water in both liuid and vapour form. &his strong affinit$ produces swelling of the fibres connected with the uptake of water, which facilitates d$eing in water$ solutions. -nlike most s$nthetic fibres, all natural fibres are nonthermoplastic that is, the$ do not soften when heat is applied. At temperatures below the point at which the$ will decompose, the$ show little sensitivit$ to dr$ heat, and there is no shrinkage or high etensibilit$ upon heating, nor do the$ become brittle if cooled to below freezing. %atural fibres tend to $ellow upon eposure to sunlight and moisture, and etended eposure results in loss of strength. All natural fibres are particularl$ susceptible to microbial !ecomposition, including mildew and rot. *ellulosic fibres are decomposed b$ aerobic bacteria (those that live onl$ in o$gen) and fungi. *ellulose mildews and decomposes rapidl$ at high humidit$ and high temperatures, especiall$ in the absence of light. +ool and silk are also sub/ect to microbial decomposition b$ bacteria and molds. Animal fibres are also sub/ect to damage b$ moths and carpet beetles termites and silverfish attack cellulose fibres. 0rotection against both microbial damage and
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insect attacks can be obtained b$ chemical modification of the fibre substrate modern developments allow treatment of natural fibres to make them essentiall$ immune to such damage.
A"# To fin! the effect of aci!s an! alkalies on tensile stren$th of cotton% silk an! wool fibres&
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Apparatus Reuirements'( *otton, wool, silk, pol$ester, hook, weight hanger, weights.
Chemical Reuirement'( $drochloric acid( 2314) and sodium h$droide(2314 ).
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Proce23re"-
. C+t o+t e4+a* *e2gth o! cotto2( )oo* a2% si*9 thea%s !o, gi=e2 sa,0*es. The thea%s sho+*% -e 2ea*" the sa,e thic92ess. 5. Dete,i2e the te2si*e ste2gth o! each 3-e as e<0*ai2e% i2 e<0ei,e2t . . Soa9 a gi=e2 thea% i2to a %i*+te so*+tio2 o! so%i+, h"%o
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!4ser56tio7s"-
SI.N T"0e o! O 3-e.
. 5. . /.
cotto2 )oo* si*9 0o*"este
Te2si*e ste2gth o! 3-eN Be!oe a!te soa9i2g a!te soa9i2g Soa9i2g. i2 NaOH. HCL.
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CO)C*+,"O)& *onclusions drew from the eperiment are:' 1. Alkalies decrease the tensile strength of woolen fibers. . Acids practicall$ do not affect this fiber. ". &ensile strength of cotton thread is decreased b$ acids and it remains unaffected b$ alkalis. 5. %$lon fiber is practicall$ unaffected b$ both acids and alkalies.
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-RECA+T"O),'( 1. &hread must be of identical diameters. . Alwa$s take the same length of threads. ". Add the weights in small amount ver$ slowl$.
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BIBLI!GRAP8
Comprehe7si5e pr6ctic69 chemistry-XI +i:ipe2i6 E7cyc9ope2i6 Brit677ic6 !79i7e E7cyc9ope2i6 ;;;te=
