简介:Theuniaxialratchetingbehaviorofapolyetherimide(PEI)polymer'TECAPEI'wasstudiedusingstress-controlledcyclicloadingatroomtemperature,includingbothcyclictension-compressionwithnon-zerotensilemeanstressandtension-unloadingtests.Theexperimentalobservationswerefocusedonthetime-dependentratchetingofthePEIpolymerrevealedincyclictestsatdiversestressratesandwithdifferentpeakstressholdingtimes.TheresultsshowedthatthePEIpolymershowsobviousratchetingdeformation;i.e.,theratchetingstrainaccumulatesprogressivelyinthetensiledirectionduringstress-controlledcyclictestswithnon-zeromeanstress.Theratchetingishighlydependentontheappliedmeanstressandstressam-plitude,andisalsocharacterizedbyastrongtime-dependencyduringthecyclicstressingatdiversestressratesandwithdifferentpeakstressholdingtimes.Thetime-dependentratchetingofthePEIpolymeriscausedmainlybyitsremarkableviscosity.AcomparisonoftheratchetingoccurringbeforeandbeyondtheultimatestresspointofthePEIpolymershowedthattheratchetingbeyondtheultimatestresspointismoresignificantthanthatoccurringbeforethatpoint.
简介:Thepresentpaperdescribesexperimentsaimedatdelineatingsignificantchemicalcharacteristicsofelectrochemicalreactionsinpolymericsolutions,includinghowrigidsolventenvironmentsaffectmasstransportrates,andalsodiscussesthepossibilitythatthemicroelectrodecoatedwithpoly(ethyleneoxide)(PEO)filmcanbeusedasgassensor.
简介:IntroductionMoleculeimprintingtechnologyhasmadegreatprogressinmakingchiralstationaryphasewithpredeterminedchiralselectivityagainstenantiomerssuchasaminoacidandtheirderivatives;sugarandtheirderivatives;naproxenandmethylbenZylamine’-’.Functionalmonomer...
简介:DistributedLagrangeMultiplier/FictitiousDomain(DLM/FD)methodwasemployedtosimulatethechannelflowwithpolymersuspension.ThepolymermoleculesweremodeledasFinitelyExtensibleNonlinearElastic(FENE)chainsandFENEchaincluster.Thecoiled-stretchedtransitionofFENEchainswasexaminedandthechangeinconfigurationofFENEchainswaspresented.Theaveragevelocityprofileofthefullydevelopedchannelflowwith64FENEchainswasgivenandfittedwellwiththepower-lawcurve.Thechangeofchainclusterconfigurationwasalsosimulated.ThesesimulationsshowthatDLM/FDmethodiscapableofsimulatingthemotionofnotonlyFENEchain,butalsoFENEchaincluster.
简介:Twokindsofrhodiumcatalystssupportedoncross-linkedstyrene-divinylbenzenecopolymerscontainingbipyridineoro-phenylenediaminehavebeenpreparedandfoundtodisplayhighactivityformethylacetatecarbonylationtoformaceticanhydride,theactivitiesareevenhigherthantheirhomogeneouscounterparts.XPSanalysiswasusedtocharacterizethesyntheticcatalysts.TheapparentactivationparametersweredeterminedtobeEα=73.3KJ/mol,ΔH^≠=66.3KJ/mol,ΔS^≠=-28.6eu.Theseparametersareveryclosetothoseinmethanolcarbonylationandimplytohaveanalogousmechanisminbothcases.
简介:Sphericalmacroporousadsorbentswithactivesitescapableofhydrogenbondingadsorptionbasedonurea-formaldehydecondensedpolymerweresynthesizedviareversedsuspensionpolymerization.Thepropertiesoftheobtainedadsorbentwerealsoinvestigatedindetail.Theresultsshowedthatthewaterpermeabilitycouldbeimprovedbyaddinghydroxyl-contatiningorganiccompoundmoietyintotheadsorbent.Thespecificsurfaceareaandaverageporediameteroftheseadsorbentsincreaswedwhiletheporosityfirstincreasedthendecreasedwiththeincreaseoftheamountoftheaddedhydroxyl-containingcompound.
简介:PolymerLBfilmscontainingphotofuntionalgroupswerepreparedbythecopolymerizationofN-dodecylacrylamide(DDA),whichhasanexcellentpropertytoformastablemonolayerandLBmultilayerswithphotofunctionalmonomers.Tris(2,2’-bipyridine)rutheniumcomplex,Ru(bpy)32+,oneofthemostwell-knownredox-activesensitizer,wasincorporatedintotheDDAcopolymer.ThephotogalvaniceffectbasedonthephotoinducedelectrontransferusingtherutheniumcomplexinthepolymerLBmonolayerwasdiscussed.
简介:Awell-dispersedmetallicpalladiumcatalystmodifiedbypolymer-anchoredthioetherligandswasusedforthehydrogenationofcyclopentadienetocyclopentenewithhighactivityandselectivityinambientcondition.Theevidencestoshowthemodificationofcatalyticpropertiesbypolymeranchoredligandsweregiven.
简介:Theionictransportprocessinpolymerelectrolytes(suchaspolyethyleneoxide)wassimulatednumericallyonatwodimensionalsquarelatticewherechargecarriersareaccommodatedbythelatticesitesconnectedrandomlywithavailablebondstorepresenttheamorphouschainconfiguration.Followingthedynamicbondpercolationtheory(DBPT),thechainmotioncontributiontotheionicconductionwasincorporatedviaperiodicalrenewaloftherandombondconfiguration.TocheckandextendthepredictionmadebyDBPTemployingglobalabruptbondrenewal,spatialcorrelationofthebondreassignmentwasintroducedtothesystemby:1)regionalbondrenewaland2)organizedbondmotion.ItisfoundthatthedifferencebetweenthediffusivitiessimulatedinvolvingregionalbondrenewalandthoseofDBPTbecomesnegligiblewhenthebondrenewalrateapproachesthecarrierhoppingrate.
简介:Theeffectofwettabilityonpolymerbehaviorinporousmediaisinvestigatedthroughaseriesofsyntheticpolymerfloodsconductedinwater-andoil-wetBentheimandBereasandstonecores.Anewexperimentalsetupisusedinwhichthecoreeffluentpolymerconcentrationsarenotmeasuredduringpolymerflooding,butinsteadarepassedthroughacapillarytubethatisconnectedtothecoreoutlet.Usingthenotionofintrinsicviscosity,anapproximateexpressionispresentedthatcanbeusedtodeterminethebreakthroughtimeoftheinjectedpolymersolution.Inaddition,polymeradsorption,inaccessibleporevolume,andapparentviscositiesareevaluatedforallcoresandwettingconditions.Ingeneral,inthepresenceofresidualoil,theoil-wetcoresdisplaythelowestdegreeofpolymerretention(Berea)andthelowestinaccessibleporevolume-IPV(Bentheim).ThelargestwettabilityimpactonthepolymerbehaviorinporousmediaappearstobefortheBereaformation;polymerretentioninoil-wetcoresdecreases90%andIPV52%comparedtothecorrespondingamountsforthewater-wetones.Ontheotherhand,theestimatedpolymerretentionandIPVvaluesappeartobesimilarfortheoil-andwater-wetBentheimcores,thisisattributedtoquestionablewettabilityalteration.
简介:Inthispaper,wereportahigh-performanceP3HT/PCBMbulk-heterojunctionsolarcellwithapowerconversionefficiencyof4.85%fabricatedbyadjustingthepolymercrystallinityandnanoscalephaseseparationusinganultrasonicirradiationmixingapproachforthepolymer.ThegrazingincidenceX-raydiffraction,UV/Visspectroscopic,andatomicforcemicroscopicmeasurementresultsfortheP3HT/PCBMblendfilmsrevealthattheP3HT/PCBMfilmfabricatedbyultrasonicirradiationmixingoftheP3HTandPCBMsolutionsfor10minhasahigherdegreeofcrystallinity,ahigherabsorptionefficiency,andbetterphaseseparation,whichtogetheraccountforthehigherchargetransportpropertiesandphotovoltaiccellperformance.
简介:ToraisetheroomtemperatureionicconductivityandimprovethemechanicalstrengthofaPEO-basedpolymerelectrolyte,anoncrystallinetwo-componentepoxyelectrolytesystemhasbeenprepared.Thediglycidyletherofpolyethyleneglycolsasprecursorsofthesystemweresynthesizedbyatwo-stepprocess.Thepresumedstructureoftheproductwascharacterized,by13C,1HNMRandIRspectroscopy.Itwasfoundthataside-reactionoccurredbetweenthesecondaryhydroxylgroupofPEG-chlorohydrinandepichlorohydrininsomedegree,resultinginaby-productcontaining—CH2Clsidegroup.Byselectingacharacteristicsignal,whichisundistortedbytheincreaseinthelengthofCH2CH2—Osegment,a1HNMRapproachofdeterminingtheequivalentepoxyweight(EEW)wasproposed.ThemethodisvalidtospecimenseventhoughtheEEWisashighas2,000.TheexaminationofthespecimensbyDSCshowedthatepoxidationgreatlydepressedthecrystallinityofthePEG’s,whereastheTgwasraised.