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1、MaterialsChemistryandPhysics98(2006)248255Aninvestigationonchangesinchemicalpropertiesofpureethylene-propylene-dienerubberinaqueousacidicenvironmentsSusantaMitraa,b,AfshinGhanbari-Siahkalia,∗,PeterKingshotta,SørenHvilstedb,KristofferAlmdalaaTheDanishPolymerCentre,
2、RisøNationalLaboratory,Building124,P.O.Box49,Frederiksborgvej399,DK-4000Roskilde,DenmarkbTheDanishPolymerCentre,DepartmentofChemicalEngineering,TechnicalUniversityofDenmark,Building423,DK-2800KongensLyngby,DenmarkReceived9June2005;accepted6September2005AbstractThe
3、influenceoftwoaqueousacidicenvironmentsontwotypesofpureethylene-propylene-diene(EPDM)rubber(i.e.,elastomer)thinfilmsisstudied.AttenuatedtotalreflectanceFouriertransforminfraredspectroscopy(ATR-FTIR)resultsrevealedtheformationofseveraloxygenatedspeciesonthesurfaceafte
4、rexposure.RamanspectroscopyalongwithATR-FTIRresultsconfirmedthevulnerabilityoftheolefinicdoublebonds(CC)of5-ethylidene-2-norbornene(ENB)inacidicenvironments.Inaddition,theaggressivenatureof20%Cr(VI)/H2SO4wasalsoobservedthroughanincreaseinoxygenatedspeciesformationon
5、thesurfaceofEPDMrubberscomparedto20%H2SO4underidenticalconditions.ComplexformationonthesurfaceofEPDMsamplesexposedto20%Cr(VI)/H2SO4throughreactionsofcarboxylicgroups(generatedduetoEPDMdegradation)withCr(III)(formedduetoreductionofCr(VI))wasalsoevidentinATR-FTIR.Fi
6、nally,alltheoxygenatedspeciescombinedtoformcrosslinkingasobservedbytheincreaseingelfractionwithexposuretime.Effectofmolarmassonchemicalchangeswasnoticedassampleswithhighermolarmasseswerefoundtoformrelativelyhigheramountofgeluponexposure.However,nosignificanteffecto
7、flongchainbranchingwasnoticed.Onthisbasis,plausiblesurfacedegradationmechanismsareproposed.©2005ElsevierB.V.Allrightsreserved.Keywords:EPDM;Thinfilms;Elastomers;FTIR;Ramanspectroscopyandscattering;Gelfraction;Surfaces;Acid1.IntroductionThus,weinvestigatetheseconseq
8、uencesbymeansofattenu-atedtotalreflectanceFouriertransformedinfraredspectroscopyEthylene-propylene-dienerubber(EPDM)isoneofthemost(ATR-FTIR),Ramanspectro
