Manufacture of Synthetic Rubber

8/18/2019 Manufacture of Synthetic Rubber

1/22

PE 391 Manufacture of Synthetic Rubber

Lecture 1

Overview

Dr. Ahmed E. A. e!mi

https://www.ahelmiconsultant.com/

https://www.ahelmiconsultant.com/https://www.ahelmiconsultant.com/


2/22

"our#e $o%ic#

• Overview on Rubber

• "!a##ification of Synthetic Rubber

• &enera! "haracteri#tic# of Rubber

• Raw Materia!# for Rubber Production

• 'utadiene Rubber

• Styrene 'utadiene Rubber (S'R)

• *itri!e Rubber (*R)


3/22


4/22

E MCH 213D Material Selection - 4

A#hby Materia! Se!ection "hart

http://www-materials.en.cam.ac.u!/mpsite/tutorial/non"#E/selchart.html

http://www-materials.eng.cam.ac.uk/mpsite/tutorial/non_IE/selchart.htmlhttp://www-materials.eng.cam.ac.uk/mpsite/tutorial/non_IE/selchart.html


5/22

*atura! Rubber

2#o%rene

2#o%rene

"4

"5"("3)+"5"

http://upload.wikimedia.org/wikipedia/commons/5/50/Isoprene.svghttp://upload.wikimedia.org/wikipedia/commons/5/50/Isoprene.svg


6/22

*atura! Rubber $ %ol&mer o' #soprene

Po!y2#o%rene(mo#t!y "i#+ 167 2#omer)


7/22

The Main Rubber TreeHevea Brasiliensis

http://upload.wikimedia.org/wikipedia/commons/4/49/Latex_-_Hevea_-_Cameroun.JPG


8/22

*atura! Rubber

• *atura! rubber ( also calle) "aoutchouc( is an e!a#tomer

*an elastic h&)rocar+on pol&mer , that was oriinall& )erie)'rom !ate8( a mil!& colloi) pro)uce) +& some plants.

• he plants woul) +e tappe)0( that is( an incision ma)e intothe +ar! o' the tree an) the stic!&( mil! colore) !ate8 uicecollecte) an) re'ine) into a usa+le ru++er.

• he puri'ie) 'orm o' natural ru++er is the chemicalcompoun) %o!yi#o%rene( which can also +e pro)uce)s&ntheticall&.

• atural u++er is use) etensiel& in man& applicationsan) pro)ucts( as is s&nthetic ru++er. #t is normall& er&stretch& an) 'lei+le an) etremel& waterproo'.

http://en.wikipedia.org/wiki/Elastomerhttp://en.wikipedia.org/wiki/Elasticity_(physics)http://en.wikipedia.org/wiki/Hydrocarbonhttp://en.wikipedia.org/wiki/Polymerhttp://en.wikipedia.org/wiki/Latexhttp://en.wikipedia.org/wiki/Colloidhttp://en.wikipedia.org/wiki/Isoprenehttp://en.wikipedia.org/wiki/Isoprenehttp://en.wikipedia.org/wiki/Colloidhttp://en.wikipedia.org/wiki/Latexhttp://en.wikipedia.org/wiki/Polymerhttp://en.wikipedia.org/wiki/Hydrocarbonhttp://en.wikipedia.org/wiki/Elasticity_(physics)http://en.wikipedia.org/wiki/Elastomer


9/22

*atura! Rubber

i#tory

• $he rubber tree initia!!y ,rew in South America. "har!e# Marie de La "ondamine i#credited with introducin, #am%!e# of rubber to the Acadmie Roya!e de# Science# ofrance in 1:3;.

• 2n 1:16 a %a%er %re#ented by rano#e%h Prie#t!ey6 in1::?6 that a %iece of the materia! wa# e8treme!y ,ood for rubbin, off %enci! mar@# on%a%er6 hence the name rubber . Later it #!ow!y made it# way around En,!and.

• South America remained the main #ource of the !imited amount# of !ate8 rubber that wereu#ed durin, much of the 19th century. 2n 14:;6 enry =ic@ham ,athered thou#and# ofrubber tree #eed# from 'rai!6 and the#e were ,erminated in Bew &arden#6 En,!and. $he#eed!in,# were then #ent to "ey!on (Sri Lan@a)6 2ndone#ia6 Sin,a%ore and 'riti#h Ma!aya.Ma!aya (now Ma!ay#ia) wa# !ater to become the bi,,e#t %roducer of rubber. About 1??year# a,o6 the "on,o ree State in Africa wa# a!#o a #i,nificant #ource of natura! rubber!ate8. Liberia and *i,eria a!#o #tarted %roduction of rubber.

• 2n 2ndia6 commercia! cu!tivation of natura! rubber wa# introduced by the 'riti#h %!anter#6a!thou,h the e8%erimenta! effort# to ,row rubber on a commercia! #ca!e in 2ndia were

initiated a# ear!y a# 14:3 at the 'otanica! &arden#6 "a!cutta. $he fir#t commercia! Hevea %!antation# in 2ndia were e#tab!i#hed at $hatte@adu in Bera!a in 19?.

http://en.wikipedia.org/wiki/Charles_Marie_de_La_Condaminehttp://en.wikipedia.org/wiki/Acad%C3%A9mie_Royale_des_Scienceshttp://en.wikipedia.org/wiki/Fran%C3%A7ois_Fresneauhttp://en.wikipedia.org/wiki/Joseph_Priestleyhttp://en.wikipedia.org/wiki/Pencilhttp://en.wikipedia.org/wiki/Henry_Wickhamhttp://en.wikipedia.org/wiki/Brazilhttp://en.wikipedia.org/wiki/Kew_Gardenshttp://en.wikipedia.org/wiki/Ceylonhttp://en.wikipedia.org/wiki/Sri_Lankahttp://en.wikipedia.org/wiki/Indonesiahttp://en.wikipedia.org/wiki/Singaporehttp://en.wikipedia.org/wiki/British_Malayahttp://en.wikipedia.org/wiki/Malaysiahttp://en.wikipedia.org/wiki/Congo_Free_Statehttp://en.wikipedia.org/wiki/Liberiahttp://en.wikipedia.org/wiki/Nigeriahttp://en.wikipedia.org/wiki/Calcuttahttp://en.wikipedia.org/wiki/Keralahttp://en.wikipedia.org/wiki/Keralahttp://en.wikipedia.org/wiki/Calcuttahttp://en.wikipedia.org/wiki/Nigeriahttp://en.wikipedia.org/wiki/Liberiahttp://en.wikipedia.org/wiki/Congo_Free_Statehttp://en.wikipedia.org/wiki/Malaysiahttp://en.wikipedia.org/wiki/British_Malayahttp://en.wikipedia.org/wiki/Singaporehttp://en.wikipedia.org/wiki/Indonesiahttp://en.wikipedia.org/wiki/Sri_Lankahttp://en.wikipedia.org/wiki/Ceylonhttp://en.wikipedia.org/wiki/Kew_Gardenshttp://en.wikipedia.org/wiki/Brazilhttp://en.wikipedia.org/wiki/Henry_Wickhamhttp://en.wikipedia.org/wiki/Pencilhttp://en.wikipedia.org/wiki/Joseph_Priestleyhttp://en.wikipedia.org/wiki/Fran%C3%A7ois_Fresneauhttp://en.wikipedia.org/wiki/Acad%C3%A9mie_Royale_des_Scienceshttp://en.wikipedia.org/wiki/Charles_Marie_de_La_Condamine


10/22

R bb St St i Di


11/22

Rubber Stre## Strain Dia,ramA $y%ica! E!a#tic 'ehavior

with y#tere#i# Loo%

y#tere#i#C•If the input varies from an initial point to a finalpoint and then retraces its value back to the initialpoint, then the two paths of the output should beidentical. If there is hysteresis in the system; thenthe input/output paths will not coincide.

•The stress-strain curve for rubber shows that thebehavior as it is loaded is not the same as when itis unloaded. The curves form a Hysteresis Loop.


12/22

atural u++er

• Pro%ertie#

u++er ehi+its uni5ue ph&sical an) chemical properties. u++er6sstress-strain +ehaior is o'ten mo)ele) as h&perelastic.

• 7win to the presence o' a )ou+le +on) in each repeat unit( naturalru++er is sensitie to o8one crac!in.

• So!vent#• here are two main solents 'or ru++er: turpentine an) naphtha

*petroleum,. he 'ormer has +een in use since 1:;7 when 9ranois9resnau ma)e the )iscoer&. ;ioanni 9a++roni is cre)ite) with the)iscoer& o' naphtha as a ru++er solent in 1


13/22

%roperties o' u++er

• "hemica! ma@e+u%• ?ate is a natural pol&mer o' isoprene *most o'ten cis-1(4-pol&isoprene, @

with a molecular weiht o' 1AA(AAA to 1(AAA(AAA.• &picall&( a small percentae *up to B o' )r& mass, o' other materials( such

as proteins( 'att& aci)s( resins an) inoranic materials *salts, are 'oun) in

natural ru++er.

• %ol&isoprene is also create) s&ntheticall&( pro)ucin what is sometimesre'erre) to as s&nthetic ru++er.

• Some natural ru++er sources calle) utta-percha are compose) o' trans-1(4-pol&isoprene( a structural isomer which has similar( +ut not i)entical(properties.

• atural ru++er is an elastomer an) a thermoplastic. Howeer( it shoul) +enote) that once the ru++er is ulcani8e)( it will turn into a thermoset. Mostru++er in eer&)a& use is ulcani8e) to a point where it shares properties o'+oth i.e.( i' it is heate) an) coole)( it is )era)e) +ut not )estro&e).

http://en.wikipedia.org/wiki/Polymerhttp://en.wikipedia.org/wiki/Isoprenehttp://en.wikipedia.org/wiki/Molecular_weighthttp://en.wikipedia.org/wiki/Proteinshttp://en.wikipedia.org/wiki/Fatty_acidshttp://en.wikipedia.org/wiki/Resinshttp://en.wikipedia.org/wiki/Gutta-perchahttp://en.wikipedia.org/wiki/Structural_isomerhttp://en.wikipedia.org/wiki/Elastomerhttp://en.wikipedia.org/wiki/Thermoplastichttp://en.wikipedia.org/wiki/Thermosethttp://en.wikipedia.org/wiki/Thermosethttp://en.wikipedia.org/wiki/Thermoplastichttp://en.wikipedia.org/wiki/Elastomerhttp://en.wikipedia.org/wiki/Structural_isomerhttp://en.wikipedia.org/wiki/Gutta-perchahttp://en.wikipedia.org/wiki/Resinshttp://en.wikipedia.org/wiki/Fatty_acidshttp://en.wikipedia.org/wiki/Proteinshttp://en.wikipedia.org/wiki/Molecular_weighthttp://en.wikipedia.org/wiki/Isoprenehttp://en.wikipedia.org/wiki/Polymer


14/22

atural ru++er

is an elastomer an)

a thermoplastic

• $ thermo%!a#tic( also !nown as a thermo#oftenin,%!a#tic( is a pol&mer that turns to a li5ui) when heate)an) 'ree8es to a er& lass& state when coole)su''icientl&.

• Most thermoplastics are hih-molecular-weiht pol&mers whose chains associate throuh wea!Fan )er Gaals 'orces *pol&eth&lene, stroner)ipole-)ipole interactions an) h&)roen +on)in *n&lon, or een stac!in o' aromatic rins *pol&st&rene,.

• hermoplastic pol&mers )i''er 'rom thermosettin pol&mers *>a!elite, in that the& can +e remelte) an)remoul)e). Man& thermoplastic materials area))ition pol&mers e..( in&l chain-rowth pol&mers

such as pol&eth&lene an) pol&prop&lene.

http://en.wikipedia.org/wiki/Elastomerhttp://en.wikipedia.org/wiki/Thermoplastichttp://en.wikipedia.org/wiki/Polymerhttp://en.wikipedia.org/wiki/Molecular_masshttp://en.wikipedia.org/wiki/Polymerhttp://en.wikipedia.org/wiki/Chain_(sequence)http://en.wikipedia.org/wiki/Van_der_Waals_forcehttp://en.wikipedia.org/wiki/Polyethylenehttp://en.wikipedia.org/wiki/Dipolehttp://en.wikipedia.org/wiki/Hydrogen_bondhttp://en.wikipedia.org/wiki/Nylonhttp://en.wikipedia.org/wiki/Aromatichttp://en.wikipedia.org/wiki/Polystyrenehttp://en.wikipedia.org/wiki/Thermosetting_plastichttp://en.wikipedia.org/wiki/Bakelitehttp://en.wikipedia.org/wiki/Addition_polymerhttp://en.wikipedia.org/wiki/Vinylhttp://en.wikipedia.org/wiki/Polypropylenehttp://en.wikipedia.org/wiki/Polypropylenehttp://en.wikipedia.org/wiki/Vinylhttp://en.wikipedia.org/wiki/Addition_polymerhttp://en.wikipedia.org/wiki/Bakelitehttp://en.wikipedia.org/wiki/Thermosetting_plastichttp://en.wikipedia.org/wiki/Polystyrenehttp://en.wikipedia.org/wiki/Aromatichttp://en.wikipedia.org/wiki/Nylonhttp://en.wikipedia.org/wiki/Hydrogen_bondhttp://en.wikipedia.org/wiki/Dipolehttp://en.wikipedia.org/wiki/Polyethylenehttp://en.wikipedia.org/wiki/Van_der_Waals_forcehttp://en.wikipedia.org/wiki/Chain_(sequence)http://en.wikipedia.org/wiki/Polymerhttp://en.wikipedia.org/wiki/Molecular_masshttp://en.wikipedia.org/wiki/Polymerhttp://en.wikipedia.org/wiki/Thermoplastichttp://en.wikipedia.org/wiki/Elastomer


15/22

7nce the ru++er is ulcani8e)(

it will turn into a thermo#et

• $ thermo#ettin, %!a#tic( also !nown as a thermo#et( ispol&mer material that irreersi+l& cures *Cross-lin!e),. he curema& +e )one throuh heat *enerall& a+oe 2AA C *3=2 9,,(throuh a chemical reaction( or irra)iation such as

electron +eam processin.• hermoset materials are usuall& li5ui) or mallea+le prior to

curin an) )esine) to +e mol)e) into their 'inal 'orm( or use)as a)hesies. 7thers are soli)s li!e that o' the mol)incompoun) use) in semicon)uctors an) interate) circuits *#C,.

• $ccor)in to #I%$C recommen)ation: $ thermosettin pol&meris a prepol&mer in a so't soli) or iscous state that chanesirreersi+l& into an in'usi+le( insolu+le pol&mer networ! +&curin. Curin can +e in)uce) +& the action o' heat or suita+le

ra)iation( or +oth. $ cure) thermosettin pol&mer is calle) athermoset.

http://en.wikipedia.org/wiki/Thermosethttp://en.wikipedia.org/wiki/Polymerhttp://en.wikipedia.org/wiki/Curing_(chemistry)http://en.wikipedia.org/wiki/Irradiationhttp://en.wikipedia.org/wiki/Electron_beam_processinghttp://en.wikipedia.org/wiki/Malleablehttp://en.wikipedia.org/wiki/Molding_(process)http://en.wikipedia.org/wiki/Adhesivehttp://en.wikipedia.org/wiki/Semiconductorshttp://en.wikipedia.org/wiki/Integrated_circuitshttp://en.wikipedia.org/wiki/IUPAChttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/IUPAChttp://en.wikipedia.org/wiki/Integrated_circuitshttp://en.wikipedia.org/wiki/Semiconductorshttp://en.wikipedia.org/wiki/Adhesivehttp://en.wikipedia.org/wiki/Molding_(process)http://en.wikipedia.org/wiki/Malleablehttp://en.wikipedia.org/wiki/Electron_beam_processinghttp://en.wikipedia.org/wiki/Irradiationhttp://en.wikipedia.org/wiki/Curing_(chemistry)http://en.wikipedia.org/wiki/Polymerhttp://en.wikipedia.org/wiki/Thermoset


16/22

Rubber E!a#ticity

• 2n mo#t e!a#tic materia!#6 #uch a# meta!# u#ed in #%rin,#6 the e!a#tic behavior i# cau#ed by bond di#tortion#. =hen force i# a%%!ied6 bond !en,th# deviate from the (minimum ener,y) eui!ibrium and#train ener,y i# #tored e!ectro#tatica!!y. Rubber i# often a##umed to behave in the #ame way6 but itturn# out thi# i# a %oor de#cri%tion. Rubber i# a curiou# materia! becau#e6 un!i@e meta!#6 #trainener,y i# #tored therma!!y.

• 2n it# re!a8ed #tate6 rubber con#i#t# of !on,6 coi!ed+u% %o!ymer chain# that are inter!in@ed at a few%oint#. 'etween a %air of !in@#6 each monomer can rotate free!y about it# nei,hbor6 thu# ,ivin, each#ection of chain !eeway to a##ume a !ar,e number of ,eometrie#6 !i@e a very !oo#e ro%e attached to a

%air of fi8ed %oint#. At room tem%erature6 rubber #tore# enou,h @inetic ener,y #o that each #ection ofchain o#ci!!ate# chaotica!!y6 !i@e the above %iece of ro%e bein, #ha@en vio!ent!y. $he entro%y mode! ofrubber wa# deve!o%ed in 1937 by =erner Buhn.

• =hen rubber i# #tretched6 the !oo#e %iece# of ro%e are taut and thu# no !on,er ab!e to o#ci!!ate.$heir @inetic ener,y i# ,iven off a# e8ce## heat. $herefore6 the entro%y decrea#e# when ,oin, fromthe re!a8ed to the #tretched #tate6 and it increa#e# durin, re!a8ation. $hi# chan,e in entro%y can a!#obe e8%!ained by the fact that a ti,ht #ection of chain can fo!d in fewer way# (=) than a !oo#e #ectionof chain6 at a ,iven tem%erature (nb. entro%y i# defined a# S5@F!n(=)). Re!a8ation of a #tretched

rubber band i# thu# driven by an increa#e in entro%y6 and the force e8%erienced i# not e!ectro#tatic6rather it i# a re#u!t of the therma! ener,y of the materia! bein, converted to @inetic ener,y. Rubberre!a8ation i# endothermic6 and for thi# rea#on the force e8erted by a #tretched %iece of rubberincreases with tem%erature. (Meta!#6 for e8am%!e6 become #ofter a# tem%erature increa#e#).

• $he materia! under,oe# adiabatic coo!in, durin, contraction. $hi# %ro%erty of rubber can ea#i!y beverified by ho!din, a #tretched rubber band to your !i%# and re!a8in, it. Stretchin, of a rubber band i#in #ome way# euiva!ent to the com%re##ion of an idea! ,a#6 and re!a8ation i# euiva!ent to it#e8%an#ion. *ote that a com%re##ed ,a# a!#o e8hibit# e!a#tic %ro%ertie#6 for in#tance in#ide an

inf!ated car tire.

http://en.wikipedia.org/wiki/Metalshttp://en.wikipedia.org/wiki/Coil_springhttp://en.wikipedia.org/wiki/Chemical_bondhttp://en.wikipedia.org/wiki/Electrostatic_potentialhttp://en.wikipedia.org/wiki/Thermal_energyhttp://en.wikipedia.org/wiki/Disulfide_bondhttp://en.wikipedia.org/wiki/Room_temperaturehttp://en.wikipedia.org/wiki/Kinetic_energyhttp://en.wikipedia.org/wiki/Entropyhttp://en.wikipedia.org/wiki/Werner_Kuhnhttp://en.wikipedia.org/wiki/Entropyhttp://en.wikipedia.org/wiki/Rubber_bandhttp://en.wikipedia.org/wiki/Endothermichttp://en.wikipedia.org/wiki/Adiabatic_processhttp://en.wikipedia.org/wiki/Gas_compressionhttp://en.wikipedia.org/wiki/Gas_compressionhttp://en.wikipedia.org/wiki/Adiabatic_processhttp://en.wikipedia.org/wiki/Endothermichttp://en.wikipedia.org/wiki/Rubber_bandhttp://en.wikipedia.org/wiki/Entropyhttp://en.wikipedia.org/wiki/Werner_Kuhnhttp://en.wikipedia.org/wiki/Entropyhttp://en.wikipedia.org/wiki/Kinetic_energyhttp://en.wikipedia.org/wiki/Room_temperaturehttp://en.wikipedia.org/wiki/Disulfide_bondhttp://en.wikipedia.org/wiki/Thermal_energyhttp://en.wikipedia.org/wiki/Electrostatic_potentialhttp://en.wikipedia.org/wiki/Chemical_bondhttp://en.wikipedia.org/wiki/Coil_springhttp://en.wikipedia.org/wiki/Metals


17/22

Gu!canied Rubber

• Fulcani8ation o' ru++er creates more )isul'i)e +on)s +etween chains( so itshortens each 'ree section o' chain. he result is that the chains tihtenmore 5uic!l& 'or a ien lenth o' strain( there+& increasin the elastic 'orceconstant an) ma!in ru++er har)er an) less etensi+le.

• Ghen coole) +elow the lass transition temperature( the 5uasi-'lui) chainsements 'ree8e into 'ie) eometries an) the ru++er a+ruptl& loses itselastic properties( althouh the process is reersi+le. his is a propert& itshares with most elastomers.

• $t er& low temperatures( ru++er is rather +rittle it will +rea! into shar)s

when struc! or stretche). his critical temperature is the reason winter tiresuse a so'ter ersion o' ru++er than normal tires.

• he 'ailin ru++er o-rin seals that contri+ute) to the cause o' theChallener )isaster were thouht to hae coole) +elow their criticaltemperature the )isaster happene) on an unusuall& col) )a&.


18/22

Schematic presentation o' two stran)s *b!ue an) ,reen,

o' natural ru++er a'ter

ulcani8ation with elemental sul'ur.


19/22

A##i,nment H 1 to receive the an#wer #heet# on

Sunday October 19

(an#wer# in =ord fi!e)

+++++++++++• 2 + &oo,!e for (A!! data in =i@i%edia)C

• F "hemica! ormu!a F Structure F Den#ity F and 'oi!in, Point ofC

2#o%rene6 Styrene6 'utadiene6 and Acri!onitri!e

22 + De#cribe what i# meant byC

Hevea Brasiliensis, Late86 Materia! (A) i# Rubbery whi!e Materia! ' i# *on+

Rubbery6 $hermo%!a#tic Po!ymer6 $hermo#et Po!ymer6 vu!canied rubber.

222 + Search forC

=hat i# meant by y#tere#i# that characterie the Stre##+ Strain Dia,ram of

mo#t of the Rubbery materia!#.

E! ti t i


20/22

• E!a#tic y#tere#i#

• $he area in the centre of the hy#tere#i# !oo% i# the ener,y di##i%ated due to materia!%!a#ticity.

• E!a#tic hy#tere#i# wa# one of the fir#t ty%e# of hy#tere#i# to be e8amined. A #im%!e wayto under#tand it i# in term# of a rubber band with wei,ht# attached to it. 2f the to% of arubber band i# hun, on a hoo@ and #ma!! wei,ht# are attached to the bottom of the bandone at a time6 it wi!! ,et !on,er. A# more wei,ht# are loaded onto it6 the band wi!! continueto e8tend becau#e the force the wei,ht# are e8ertin, on the band i# increa#in,. =heneach wei,ht i# ta@en off6 or unloaded 6 it wi!! ,et #horter a# the force i# reduced. A# thewei,ht# are ta@en off6 each wei,ht that %roduced a #%ecific !en,th a# it wa# !oaded ontothe band now %roduce# a #!i,ht!y !on,er !en,th a# it i# un!oaded. $hi# i# becau#e theband doe# not obey oo@eI# !aw %erfect!y. $he hy#tere#i# !oo% of an idea!ied rubber

band i# #hown in the be!ow ,iven i,ureC


21/22

n one #en#e the rubber band wa# harder to #tretch when ita# bein, !oaded than when it wa# bein, un!oaded. 2n anotheren#e6 a# one un!oad# the band6 the cau#e (the force of theei,ht#) !a,# behind the effect (the !en,th) becau#e a #ma!!era!ue of wei,ht %roduce# the #ame !en,th.

n another #en#e more ener,y wa# reuired durin, the !oadin,han the un!oadin,J that ener,y mu#t have ,one #omewhere6 ita# di##i%ated or !o#t a# heat.

!a#tic hy#tere#i# i# more %ronounced when the !oadin, andn!oadin, i# done uic@!y than when it i# done #!ow!y.

ome materia!# #uch a# hard meta!# donIt #how e!a#ticy#tere#i# under a moderate !oad6 wherea# other hardateria!# !i@e ,ranite and marb!e do.

Materia!# #uch a# rubber e8hibit a hi,h de,ree ofe!a#tic hy#tere#i#.


22/22

A word of cautionC

Rubber behave# !i@e a ,a#. =hen the rubber band i# #tretched itheat# u%. 2f it i# #udden!y re!ea#ed6 the rubber coo!# down6 very

ea#y to %erceive Ku#t by touchin,.

So6 there i# a !ar,e hy#tere#i# from the therma! e8chan,e with theenvironment and a #ma!!er hy#tere#i# due to interna! friction withinthe rubber.

$hi# %ro%er6 intrin#ic hy#tere#i# cou!d be mea#ured on!y ifadiabatic i#o!ation of the rubber band i# im%o#ed.

Documents

Manufacture of Synthetic Rubber