312895024-investigatory-project-on-polymers-for-class-12-students-in-CBSE.pdf

Certifcate  This is to certiy that Mr. Mr. yash Patel Student o Xll science Roll Roll no__________ Worked on project titled-Polyer titled-Polyer held in !ha"#ati international pu$lic school durin" the acadeic year %&'(-%&'). *e #orked sincerely sincerely under un der the "uidance o aculties and prepar prepared ed this dissertation.

+,ternal +,ternal Teacher each er  Teacher  Teacher

Su$ject Su$ject

Principal

ackno#led"eent irst o all / a iensely inde$ted to ali"hty "od or his $lessin" and "race #ithout #hich / could not ha0e $een a success. / hu$ly consider a pri0ile"e and honor to e,press y heartiest and proound "ratitude to Mr. Rajendra.S.Mal#al principal !/PS Patan. or his appropriate direction 0alua$le su""estion under jud"in" assistance so "enerously e,tended to e. / #ish to e,press y deepest eelin"s o "ratitude to Mr. 1a$akishor sorokhai$a cheistry departent !/PS Patan. or his erudite in0ol0eent and sustained "uidance #hich has $een pi0otal in y project #ork. *is inute o$ser0ation precious insi"hts critical coents ha0e indeed "reatly helped to shape y ideas.  This "uidance and support recei0ed or y entire classates #ho contri$uted and #ho are contri$utin" to this project is 0ital or the success o this project. / a "rateul or their constant support and help. / also o#e sense o "ratitude to y parents or encoura"eent and support throu"hout the project.

- 2ash Patel

C31T+1TS 1. Polymer 2. Polymer science 3. Historical development 4. Laboratory synthesis 5. Mechanical properties

Introduction

While the term polymer in popular usae suests !plastic!" polymers comprise a lare class o# natural and synthetic materials $ith a variety o# properties and purposes. %atural polymer materials such as shellac and amber have been in use #or centuries. Paper is manu#actured #rom cellulose" a naturally occurrin polysaccharide #ound in plants. &iopolymers such as proteins and nucleic acids play important roles in bioloical processes. Henri &raconnot's pioneerin $or( in derivative cellulose compounds is perhaps the earliest important $or( in modern polymer science. )he development o# vulcani*ation later in the nineteenth century improved the durability o# the natural polymer rubber" sini#yin the +rst populari*ed semi,synthetic polymer. )he +rst $holly synthetic polymer" &a(elite" $as discovered in 1-/. 0ntil the 1-2s" most scientists believed that polymers $ere clusters o# small molecules called colloids" $ithout de+nite molecular $eihts" held toether by an un(no$n #orce" a concept (no$n as association theory. In 1-22" erman chemist Hermann taudiner proposed that polymers $ere comprised o# !macromolecule s! consisted o# lon chains o# atoms held toether by covalent bonds. )houh poorly received at +rst" eperimental $or( by Wallace 6arothers"Herman Mar( " and others provided #urther evidence #or taudiner's theory. &y the mid,1-3s" the macromolecular theory o# polymer structure $as $idely accepted. 7or this and other $or( in the +eld" taudiner $as ultimately a$arded the %obel Pri*e. In the intervenin century" synthetic polymer materials such as %ylon" polyethylene" )e8on" andsilicone have #ormed the basis #or a bureonin polymer industry. ynthetic polymers today +nd application in nearly every industry and area o# li#e. Polymers are used in the #abrication o# microprocessors"

 Polymer 4ppearance o real linear polyer chains as recorded usin" an atoic orce icroscope on surace under li5uid ediu. Chain contour len"th or this polyer is 6%&7 n8 thickness is 6&.7 n. 4 polymer is a lar"e olecule 9acroolecule: coposed o  repeatin" structural units. These su$units are typically connected $y co0alentcheical $onds. 4lthou"h the ter  polymer  is soeties taken to reer to plastics it actually encopasses a lar"e class o  natural and synthetic aterials #ith a #ide 0ariety o properties. !ecause o the e,traordinary ran"e o properties o polyeric aterials they play an essential and u$i5uitous role in e0eryday lie.  This role ran"es ro ailiar synthetic plastics and elastoers to natural $iopolyers such as nucleic acids  and proteins that are essential or lie. 1atural polyeric aterials such as shellac a$er and natural ru$$er ha0e $een used or centuries. 4 0ariety o other natural polyers e,ist such as cellulose #hich is the ain constituent o #ood and paper.  The list o synthetic polyers  includes synthetic ru$$er !akelite neoprene nylon P;C polystyrene polyethylene polypropylene polyacrylonitrile P;! silicone and any ore. Most coonly the continuously linked $ack$one o a polyer used or the preparation o plastics consists ainly o car$on atos. 4 siple e,aple is polyethylene #hose repeatin" unit is $ased on ethyleneonoer. *o#e0er other structures do e,ist8 or e,aple eleents such as silicon or ailiar aterials such as silicones

Polymer science Most polyer research ay $e cate"ori
includes researchers in cheistry  9especially or"anic cheistry: physics and en"ineerin". The feld o polyer science includes $oth e,periental and theoretical research. The /=P4C recoends that polyer science $e rou"hly di0ided into t#o su$disciplines> polyer cheistry  9or acroolecular cheistry: and polyer physics. /n practice the distinction $et#een the t#o is rarely clearcut.  The study o $iolo"ical polyers their structure unction and ethod o synthesis is "enerally the pur0ie# o $iolo"y $iocheistry and $iophysics. These disciplines share soe o the terinolo"y ailiar to polyer science especially #hen descri$in" the synthesis o $iopolyers such as ?14 or polysaccharides. *o#e0er usa"e di@erences persist such as the practice o usin" the ter acroolecule to descri$e lar"e non-polyer olecules and cople,es o ultiple olecular coponents such as heo"lo$in. Su$stances #ith distinct $iolo"ical unction are rarely descri$ed in the terinolo"y o polyer science. or e,aple a protein is rarely reerred to as a copolyer

Historical development Startin" in 'A'' *enri !raconnot did pioneerin" #ork in deri0ati0e cellulose copounds perhaps the earliest iportant #ork in polyer science. The de0elopent o 0ulcani
?espite si"nifcant ad0ances in synthesis and characteri
Laboratory synthesis a$oratory synthetic ethods are "enerally di0ided into t#o cate"ories step-"ro#th polyeri
Microstructure o part o a ?14 dou$le heli,biopolymer Main article> !iopolyer  There are three ain classes o $iopolyers> polysaccharides polypeptides and polynucleotides. /n li0in" cells they ay $e synthesi
Monomer arranement in copolymers

Monoers #ithin a copolyer ay $e or"ani
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9lternatin copolymers possess onoer residues> H4!...I n 9%:.

re"ularly

alternatin"

Periodic copolymers ha0e onoer residue types arran"ed in a repeatin" se5uence> H4 n!...I  $ein" di@erent ro n . tatistical copolymers  ha0e onoer residues arran"ed accordin" to a kno#n statistical rule. 4 statistical copolyer in #hich the pro$a$ility o fndin" a particular type o  onoer residue at an particular point in the chain is independent o the types o surroundin" onoer residue ay $e reerred to as a truly random copolymer 9G:. &loc( copolymers ha0e t#o or ore hoopolyer su$units linked $y co0alent $onds 97:. Polyers #ith t#o or three $locks o t#o distinct cheical species 9e.". 4 and !: are called di$lock copolyers and tri$lock copolyers respecti0ely. Polyers #ith three $locks each o a di@erent cheical species 9e.". 4 ! and C: are tered tri$lock terpolyers.

Mechanical properties

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4 polyethylene saple neckin" under tension.  The $ulk properties o a polyer are those ost oten o end-use interest. These are the properties that dictate ho# the polyer actually $eha0es on a acroscopic scale.

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Tensile strength

 The tensile stren"th  o a aterial 5uantifes ho# uch stress the aterial #ill endure $eore su@erin" peranent deoration. This is 0ery iportant in applications that rely upon a polyerJs physical stren"th or dura$ility. or e,aple a ru$$er $and #ith a hi"her tensile stren"th #ill hold a "reater #ei"ht $eore snappin". /n "eneral tensile stren"th increases #ith polyer chain len"th and crosslinkin" o polyer chains. Young's modulus of elasticity 

 2oun"Js Modulus 5uantifes the elasticity o the polyer. /t is defned or sall strains as the ratio o rate o chan"e o stress to strain. ike tensile stren"th this is hi"hly rele0ant in polyer applications in0ol0in" the physical properties o polyers such as ru$$er $ands. The odulus is stron"ly dependent on teperature.

%:L;%" 9 6ondensation Polymer 1ylon #as the result o research directed $y Wallace *ue Carothers at du Pont. The research tea #as interestedin duplicatin" the characteristics o silk. 1ylon "ained rapid acceptance or use in stockin"s and in akin" parachutes. Carothers ho#e0er #as su$ject to $outs o depression and in 'BG) shortly $eore du Pont placed nylon stockin"s on the arket8 Carothers coitted suicide $y drinkin" cyanide. a#ety Precautions Wear saety "o""les at all ties in the la$oratory.  The aterials in this e,perient are considered to,ic. They are irritants to the eyes and ucous e$ranes. Wear "lo0es and #ork in a #ell 0entilated area. • •

Materials needed •

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*e,aethylenediaine 9'(-he,anediaine: KL a5ueous solutionSe$acoyl chloride 9or adipyl chloride: KL solution in cyclohe,ane Sodiu hydro,ide 1a3* %&L a5ueous solution !eaker K& 

orceps Stirrin" rod. Procedure Pour '&  o *e,aethylenediaine solution into a K&  $eaker. 4dd '& drops o %&L sodiu hydro,ide solution. Stir. Careully add '&  o se$acoyl chloride solution $y pourin" it do#n the #all o the tilted $eaker. T#o layers should $e e0ident in the $eaker and there should $e an iediate. • •

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;" 9 6opolymer •

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Supera$sor$ants #ere ori"inally de0eloped $y the =nited States ?epartent o 4"riculture in 'B((. This aterial consisted o a "rated copolyer o hydroly
Polymer deradation

4 plastic ite #ith thirty years o e,posure to heat and cold $rake uid and sunli"ht. 1otice the discoloration s#ollen diensions and tiny splits runnin" throu"h the aterial Polyer de"radation is a chan"e in the propertiesQtensile stren"th color shape olecular #ei"ht etc.Qo a polyer or polyer-$ased product under the inuence o one or ore en0ironental actors such as heat li"ht cheicals and in soe cases "al0anic action. /t is oten due to the scission o polyer chain $onds 0ia hydrolysis leadin" to a decrease in the olecular ass o the polyer. 4lthou"h such chan"es are re5uently undesira$le in soe cases such as $iode"radation  and recyclin" they ay $e intended to pre0ent en0ironental pollution. ?e"radation can also $e useul in $ioedical settin"s. or e,aple a copolyer o Polylactic acid and poly"lycolic acid  is eployed in hydrolysa$le stitches that slo#ly de"rade ater they are applied to a #ound.

Product #ailure

Chlorine attack o acetyl resin plu$in" joint /n a fnished product such a chan"e is to $e pre0ented or delayed. ailure o saety-critical polyer coponents can cause serious accidents such as fre in the case o  cracked and de"raded polyer uel lines. Chlorineinduced crackin" o acetyl resin plu$in" joints and poly$utylene pipes has caused any serious oods in doestic properties especially in the =S4 in the 'BB&s.  Traces o chlorine in the #ater supply attacked 0ulnera$le polyers in the plastic plu$in" a pro$le #hich occurs aster i any o the parts ha0e $een poorly e,truded or injection olded. 4ttack o the acetyl joint occurred $ecause o aulty oldin" leadin" to crackin" alon" the threads o the fttin" #hich is a serious stress concentration.

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Polyer o,idation has caused accidents in0ol0in" edical de0ices. 3ne o the oldest kno#n ailure odes is o hydrolysis. 1ylon ((  is suscepti$le to acid hydrolysis and in one accident a ractured uel line led to a spilla"e o diesel into the road. / diesel uel leaks onto the road accidents to ollo#in" cars can $e caused $y the slippery nature o the deposit #hich is like $lack ice.