简介:Theoneplusone(1+1)modeofhydrosilationreactionofladderlikecis-isotaticpolyallylsilsesquioxane(AllyI-T)andpolyhydrosilsesquioxane(H-T)usingdicyclopentadienylplatinumdichloride(Cp2PtCl2)asthecatalystleadstotheformationofanewpolyorganosiloxane(POS).ThepresenceofnanoscaletubularstructureintheproductPOSwaspreliminarilyprovedbyIR,1H-NMR,differentialscanningcalorimetry(DSC),X-raydiffraction(XRD),gelpermeationchromatography(GPC),atomicforcemicroscopy(AFM)andmolecularsimulation.
简介:Thestructureofpolyimidefrom1,4-bis(3’,4’-dicarboxyphenoxy)benzeneand4,4’-oxydianilinefilmspecimensbeforeandafterhotstretchinghasbeeninvestigatedbyWAXD,DSCandFTIR.AsevidencedbyboththeWAXDandDSCresults,itcouldbebelievedthatstraininducedcrystallizationdidtakeplaceafterhotstretching.Meanwhile,shiftingpositionandsplittingofsomebandpeaksexistedontheFTIRspectrogramswereexplainedintermsoftheclosepackingofchainsandthechangesofinter-molecularcharge-transferinteractionbetweenimidegroupsandaromaticgroupsuponcrystallization.
简介:Theglassytransitionofthepolyethyleneterephthalate(PET)sampleswhichhavebeensubjectedtosolventinducedcrystallization(SINC)wasinvestigatedbymodulateddifferentialscanningcalorimetry(MDSC)anddensitymeasurement.Thedif-ferentialofheatcapacitysignal,dC_p/dTfromMDSC,wasusedtomonitortheSINCprocess.ItrevealsthattheT_gtemperatureshiftstohighervaluewiththeadvancementofSINC.Whenthetoluene-immersingtimewaslonger(168h),thedetectionofT_gbecomemoredifficult,becausesomesmallerpeaksemergedatthelowertemperaturesandtheseareexplainedasthemovementofsmallsegmentsintheamorphousregion.TheseobservedresultsareduetothemorphologyandstructureintroducedbytheSINCprocess.
简介:ThepreparationofconductingPPQfilmwasfirstreportedinthepreviouspaper.Itisveryinterestingthatthisfilmishighlysensitivetomoistureinair.ThehydrationanddehydrationofthefilmareaccompaniedbychangenotonlyincolorbutalsoinconductivityandUV-visiblespectrum.TheconductingPPQisreducedtoPPQandlosesitsconductivityafterbeingsoakedinwater.
简介:Poly(β-carboxyethylmethylsiloxane)-LiClO4andpoly(β-alkoxylethylmethylsiloxane)-LiClO4crosslinkedfllmshavebeenprepared.Theionicconductivityofthefilmsdependsonthepolymerspecies,concentrationoflithiumperchlorate,temperatureandcontentofcrosslinkingagent.Theeffectofhighpolarorganicsolvent1,4-butyrolactoneontheionicconductivityandmechanicalpropertiesofpoly(β-carhoxyethylmethylsiloxane)-LiClO4systemwasalsoinvestignied.
简介:Ionicconductivityvaluesforsegmentedpolyetherpolyurethaneurea(PEUU)complexeswithLiClO4weredeterminedandvaluesashighas~1.1×10-4S·cm-1at353Kand~1.0×10-5S·cm-1at306Kwereachieved.TheionicconductivitydatawereanalyzedusingtheVTF(Vogel-Tamman-Fulcher)equationandWLF(Williams-Landel-Ferry)typeequation.Valueshavebeenestimatedforthe"apparent"activationenergiesofiontransportfromVTFequationandtheylieintherange2.70—5.53kJ·mol-1.
简介:Thiscontributionreportsethylenepolymerizationbehavioroftitaniumcomplexesincorporatingbis(phenoxyimine)ligands.Sixphenoxy-imineTi(IV)complexes{6-R1-2-[CH=N(2,6-difluoro-3,5-diR2-4-R3Ph)]C6H3O}2TiCl2(1:R1=H,R2=H,R3=H;2:R1=H,R2=H,R3=4-vinylphenyl;3:R1=CH3,R2=H,R3=H;4:R1=CH3,R2=H,R3=4-vinylphenyl;5:R1=CH3,R2=F,R3=H;6:R1=CH3,R2=F,R3=4-vinylphenyl)havebeensynthesizedandevaluatedforethylenepolymerizationusingdriedMAO(simplifiedasDMAO)ascocatalyst.AnobviouscatalyticheterogeneityofCat2(Complex2/DMAO)towardsethylenepolymerizationwasobserved,whichwasillustratedbydecreasedactivity,multimodalmolecularweightdistributionandpartiallyimprovedparticlemorphologycomparingwithCat1.Moreover,Cat3exhibits'living'characteristicsintheprocessundercertainconditions(25°C,lessthan20min).Otherwise,themoderatetohighethylenepolymerizationactivityofca.105-106gPE/(molTi·h)andhighmolecularweight(Mw=105-106)ofpolyethylenecanbeobtainedbychangingtheskeletonstructureofthesecomplexes.
简介:Thetreatmentandresourcereuseof1,2,4-acidproducingwastewaterbyself-mademacroporousadsorptionresinND,A-107wasstudiedinthispaper.Optimumadsorptionanddesorptionprocessparameterswereacquiredbysystematicallystudy.ThepolymericresinNDA-107indicatedgoodadsorption&desorptionof1,2,4-acidinthewastewater.Theremovalefficiencyof1,2,4-acid,CODerisabout78%,72%respectively.Itisevidentthatthisadsorptionprocessisanefficienttreatmentmethodfor1,2,4-acidproducingwastewater.Atthesametime,theaccumulationandresourcereuseofl,2,4-acidcanberealizedinthisprocess.
简介:TiCl_4/MgCl_2/claycompoundcatalystwaspreparedbychemicalreaction.Exfoliatedpolypropylene(PP)/claynanocompositesweresynthesizedbyinsitupolymerizationwiththiscompoundcatalyst.Effectsofpolymerizationtemperature,polymerizationtime,propylenepressure,solventconsumptionandpre-treattimeofcatalystoncatalystactivityandcatalyticstereospecificitywerestudied.Underoptimalconditions,activityofthenano-compoundcatalystisabout88.3kg/(molTi·h).IsotacticityofPPobtainedinthenanocompositesisintherangeof89%-99%,anditsmeltingtemperatureisabout159℃.Theweight-averagemolecularweightofPPcanreach6.7×10~5-7.8×10~5,andthemolecularweightdistributionisbetween7.7and7.9.
简介:Polyolefinsthatbearachiralsidechain(typicallyanisobutylgroup)experienceaso-calledmacromolecularamplificationofchirality:thechiralside-chaininducesaslightpreferenceforeithertgortg-mainchainconformation.Thisslightconformationalbiasisamplifiedcooperativelyalongthechain,andresultsinpreferredchiralityofthemainchainhelicalconformations.Asaresult,thesepolymersdisplayaliquid-crystal(LC)phasebothinsolutionand,inthemeltasatransientphaseonthewaytocrystallization.Theexistenceoftwoprocesses(melt-LCandLC-crystaltransitions)resultsinunconventionalbehaviorsthatwerefirstanalyzedbyPinoandcollaboratorsbackin1975.Thesepolymersalsoofferameanstotestthestructuralconsequencesofrecentlyintroducedcrystallizationschemes.Theseschemespostulatetheformationofatransientliquid-crystalphaseasageneralschemeforpolymercrystallization.
简介:Gasphasereductionofcarbonmonoxidetoformaldehydeandethylenewasfoundinelectrochemicalcellwithaninorganicionexchangerα-Zr(HPO4)2·H2Ousedassolidproton-conductingelectrolyteatroomtemperatureandatmosphericpressure.ThetypeandamountoftheelectroreductionofCOdependonthedifferentmetalelectrodesandcurrentdensities,whichgivesalankbetweenheterogeneouscatalysisandelectrochemistry.
简介:Kineticsofchloride/sulfate,chloride/nitrateandnitrate/sulfateforwardexchangesandreverseexchangesatsolutionconcentrationsof1N,0.2Nand0.02Non201×7strongbaseanionexchangeresin,respectively,havebeenexaminedat25℃.Itisfoundthattheforwardandthereverseexchangeratesofthetwogivenionsatlowsolutionconcentration,respectively,underidenticalconditionscanbecontrolledbydifferentmechanisms,whilethoseathighsolutionconcentrationareallcontrolledbyparticlediffusion.Theternaryexchangeratesofsulfate/(chloride+nitrate)andnitrate/(chloride+sulfate)havealsobeenexamined.
简介:Dithia-monoaza18-Crown-6anditsimmobilizationproduct,silica-bound1,7-dithia-4-aza-10,13,16-trioxa-cyclooctadecaneviaaspacerofthreecarbonatoms,anditsplatinumcomplexhavebeensynthesized.Itisfoundthattheplatinumcomplexisanefficienthydrosilylationcatalystforolefins.TheXPSdataoftheplatinumcomplexarereported.
简介:Newmodelcompound1H,1′H-Bis(benz-Δ^4-imidazoline)2,2′-spiro-titaniumdichloridewaspreparedandthestructureofthecompoundwasdeterminedby1R,MSandelementaryanalysis.