简介:Fourkindsofpalladiumcatalystsdispersedonpoly-N-vinyl-2-pyrrolidonewerepreparedbyusingCH3OH-NaOH,NaBH4,H2OorCH3OH-H2Oasthereducingagentintheprocessofcatalystpreparation.ThecatalystswerecharacterizedbyXPS,TEM,XRDandusedforthehydrogenationofmethylacrylate.Itwasfoundthatthevalencestateofpalladiumanddistributionofpalladiumparticlesaswellasthehydrogenationrateweregreatlyaffectedbythereducingagent.ThebestevenlydispersedpalladiumcatalystshowinghighhydrogenationactivitywaspreparedusingCH3OH-NaOHasthereducingagent.
简介:Inthisstudy,apoly(etherblockamide)(Pebax1657)compositemembraneappliedforCO2capturewaspreparedbycoatingPebax1657solutiononpolyacrylonitrile(PAN)ultrafiltrationmembrane.Ethanol/watermixturewasusedasthesolventofPebaxandtheeffectsofethanol/watermassratiosandPebaxconcentrationonthepermeationpropertiesofcompositemembranewerestudied.Toenhancethecompositemembranepermeance,thegutterlayer,madefromreactiveaminosiliconecrosslinkingwithpolydimethylsiloxane(PDMS),wasdesigned.Theinfluenceofcrosslinkingdegreeofthegutterlayeronmembraneperformancewasinvestigated.Asaresult,aPebax/aminoPDMS/PANmultilayermembranewithhexaneresistancewasdeveloped,showingCO2permeanceof350GPUandCO2/N2selectivityover50.Theblendofpolyethyleneglycoldimethylether(PEG-DME)withPebaxascoatingmaterialwasstudiedtofurtherimprovethemembraneperformance.AfterbeingcombinedwithPEG-DMEadditive,CO2permeanceofthefinalPebax-PEG-DME/amino-PDMS/PANcompositemembranereached400GPUabovewithCO2/N2selectivityover65.
简介:WithN-vinyl-2-pyrrolidone(NVP)anditaconicacid(IA),poly(N-vinyl-2-pyrrolidone/itaconicacid)[P(NVP/IA)]hydrogelwassynthesizedbyfreeradicalsolutionpolymerization.ThestructureofthisP(NVP/IA)wascharacterizedbyIR.Effectsofconcentrationofitaconicacid,amountofcross-linkagent,N,N′-methylene-bis-acrylamide,reactiontemperature,andtimeonpropertiesofswellingratio(SR)ofthehydrogelwereinvestigated.Theresultsshowthatthebestswellingpropertyofthehydrogelisobtainedat50℃and1.5h.pHsensitivityincreasesastheconcentrationofitaconicacidinthehydrogelsystemincreases.Swellingratioofthehydrogeldecreasesastheamountofcross-linkagentincreases.
简介:Underdifferentreactionconditions,theexpectedandunexpectedreactionproducts(ofwhichX-raycrystallographicstructurewaspresented)ofetherificationof2-per(poly)fluoroethyl4-substitutedphenolwithβ-haloethanolcanbeobtainedrespectively.
简介:阶段PVDF水晶结构和在先存在的阶段PVDF球粒以内的豌豆的结晶化上的豌豆的效果被光显微镜学OM,红外线的光谱学红外和扫描电子显微镜学SEM调查了。结果证明阶段PVDF球粒由展出高度弄弯的像滚动的形态学的lamellae组成并且在充满豌豆的混合优先地发展。与增加豌豆集中,滚动直径增加和滚动更好与对方被分开。豌豆在interspherulitic区域使第一结晶,transcrystalline层发展。随后,豌豆的transcrystalline层继续在阶段PVDF球粒以内成长,例如在在滚动之间的区域,直到在另外的豌豆transcrystalline层或球粒上侵犯。结晶化动力学结果显示在阶段PVDF的intraspherulitic区域的豌豆晶体的生长率与阶段PVDF的结晶化温度与豌豆,而是否定豌豆的内容显示出积极关联。
简介:Inthiswork,DSCandSEMstudiesindicatethation-ligandinteractioncanbeutilizedtoenhancetheinteractionofpoly(styrene-block-2-vinylpyridine)[P(S-b-2VP)]andpolyethylenebasedionomer(Surlyn).Thecompatibilityforthisblendingsystemcanbeimprovedbythisspecialinteractionand20/80wtistheoptimumblendingcompositionwithgoodcompatibility.FTIRresultsfurthercertifythatstronginteractionsexistintheblendingsystem.
简介:Asupercriticalcarbondioxide(ScCO2)assistedphaseinversionwasdevelopedtoproducemicroporouspoly(vinylidenefluoride)(PVDF)membraneswhosemorphologycharacteristicsarisefrombothliquid-liquiddemixingandsolid-liquiddemixing(crystallization).ThisresultwasconfirmedbyFouriertransforminfraredspectroscopy(FTIR),fromwhichbothαandβcrystalswerefound.Asrevealedbycontactangleexperiment,thePVDFmembranespreparedviaScCO2assistedphaseinversionweremorehydrophobiccomparedwiththecontrolmembraneproducedviaconventionalimmersionprecipitationtechnique.Inparticular,thesamplewith15wt%PVDFpreparedat45°Cand13MPaexhibitedacontactangleof142°,whichwasmainlycausedbythemultilevelmicro-andnano-structure.Theeffectsofpolyethyleneglycol(PEG),polyvinylpyrrolidone(PVP)andlithiumchloride(LiCl)onthestructuresandcrystalformwereinvestigated.PVPpromotedtheformationofβphasecrystalform,whilePEGbooststheevolutionofαphase.LiClrestrainedthecrystallizationdegreeofPVDFmembraneunderScCO2.
简介:Ithasbeenwellknownthatfluorinatedpolyurethanesexhibituniquelylowsurfaceenergy,biocompatibilityandbiostability,thermalandoxidativestabilityandnonstickingbehavior.Consequently,thesepolymershaveattractedconsiderableinterest.However,themechanicalpropertiesoffluorinatedpolyurethanesusuallydeclinewithincreasingfluorinecontents.Theblendingoffluorinatedpolyurethaneswithnormalpolyurethanewascarriedouttoachievebalancedmechanicalandsurfaceproperties.Itwasfoundthatpolyurethanewithgoodmechanicalpropertiesandlowsurfaceenergycanbeobtainedbyaddingasmallamountoffluorinatedpolyurethane.Thefluorinatedsidechainscaneasilymigratetouppermostsurfacesoftheblendsuntillthefluorinelevelatthesurfacebecomesalmostsaturated.Ithasbeenshownfromcontactangle,XPSandAFMmeasurementsthatonlyaslittleas0.34wt%offluorinelevelisenoughtoproduceasurfacesaturatedwithfluorine,andthefluorinelevelattheuppermostsurfaceisonehundredtimeshigherthanthatintheblendbulk.Thefinaloutersurfacestructuresofthepolyurethaneblendwereindependentofthecontentofthefluorinatedpolyurethaneintheblendsduetothesurfacessaturatedbyfluorine.
简介:Carbonylationofallylhalidescatalyzedbypoly(N-vinyl-2-pyrro-lidone)anchoredpalladiumcatalystaffordsβ,r-butonicacidunderatmo-sphericpressureandatroomtemperature.Theactivityandefficiencyofthecatalystaremuchhigherthanthoseofthereportedcatalystsforthisreaction.
简介:Anovelsmallband-gapconjugatedpolymer-poly[(3-acetylpyrrole-2,5-diyl)(4-dimethylaminobenzyliene)(3-aeetylpyrrolequinodimethane-2,5-diyl)](PAPDMABE)-anditsprecursorweresynthesizedbyasimplemethodandcharacterizedby1H-NMR,FT-IR,TGAandUV-VIS.ThepolymercanbedissolvedinstrongpolarsolventssuchasDMSO,DMForNMP.Theband-gapenergyofPAPDMABEwasfoundtobe0.95eV.Theconductivityofdopedproductswithiodinefallsintherangeofasemiconductor.``
简介:3-Ethynyl-4-(trimethylsilyl)thiophene(1a)and3-ethynyl-4-bromothiophene(1b)selectivelyundergoacetylenepolymerizationsinthepresenceoftheMoCl5-andWCl6-Ph3SiHcatalyststogivesoluble,high-molecular-weightpoly(thienylacetylenes)(2)(Mwupto602000)inhighyields(upto100%).LighttransmissionspectraofTHFsolutionsof2continuouslyred-shiftwithincreasingconcentration.Theconcentratochromismshowsalogarithmicconcentrationdependence;thatis,theopticaltransitionsof2arepredictablytunablebysimplychangingtheirconcentrations.
简介:Poly(4-vinylpyridine)(P4-VP)nanofiberandfluoresentpoly(4-vinylpyridine)/porphyrin(P4-VP/TPPA)nanofiberwererespectivelypreparedbyelectrospinning.TheeffectoftheconcentrationofP4-VP/dimethylformamide(DMF)electrospinningsolutionsonthemorphologyofP4-VPnanofiberwasinvestigatedanditwasfoundthattheaveragediameterofthenanofiberofP4-VP/DMFincreasedwiththeincreaseoftheconcentrationofthespinningsolution.AftertheadditionofTPPAtotheP4-VP/DMFspinningsolution,thediameterofP4-VP/TPPAnanofiberbecameevenduetotheincreaseoftheconductivityoftheP4-VP/DMF-TPPAsolution.Thephotoluminescent(PL)spectralanalysisindicatesthattheemissionpeakpositionofP4-VP/TPPAnanofiberisalmostthesameasthatofpureTPPAatabout650nmwithoutpeakshift,andwhenitwasstoredfor20days,theemissionpeakofP4-VP/TPPAnanofiberisalsoat650nm,indicatingthatthefluorescentpropertyofP4-VP/TPPAnanofiberisstable.Fourier-transforminfrared(FTIR)spectrumconfirmsthechemicalcompositionoftheresultingP4-VP/TPPAcompositenanofiber.
简介:Aseriesofpoly(2-acetoxyethylmethacrylate)/polystyrene(PAEMA/PS)latexinterpenetratingpolymernetworks(LIPNs)werepreparedbyseededsoap-freeemulsionpolymerizationofstyreneonthecrosslinkedPAEMAseedparticlesusinganoil-solubleinitiator.ThesePAEMA/PSLIPNsshowedawell-definedphase-separatedstructurewithPSphasedispersingincontinuousPAEMAphase.ThedomainsizeofPSphasewasfoundtodependonthecrosslinkingdegreeofPAEMAseedparticlesandtheamountofsecond-stagestyrenemonomer.
简介::Twonovelpoly[(3-alkyhhiophene-2,5-diyl)-(benzylidenequinomethane-2,5-diyl)s]derivatives,poly[(3-butylthiophene-2,5-diyl)-(p-N,N-dimethylamino)benzylidenequinomethane-2,5-diyl)](PBTDMABQ)andpoly[-(3-octylthiophene2,5-diyl)-(p-N,N-dimethylamino)benzylidenequinomethane-2,5-diyl)](POTDMABQ),weresynthesized.Thebandgapsofthetwopolymersarecalculatedas1.75eVforPBTDMABQand1.69eVforPOTDMABQ,respectively.Thehomogenousfilmsofthetwopolymerswerepreparedandtheirthird-ordernonlinearopticalpropertieswerestudiedbythebackwarddegeneratefour-wavemixingat532nm.Byusingtherelativemeasurementtechnique,thethird-ordernonlinearopticalsusceptibilitiesofPBTDMABQandPOTDMABQarecalculatedas5.62×10^-9and1.22×10^-8ESU,respectively.Itisfoundthatsubstitutedalkygroupshavestrongeffectsonthebandgapandnonlinearopticalpropertiesofthetwopolymers.Therelativelybigthird-ordernonlinearopticalsusceptibilitiesandsmallbandgapofPOTDMABQresultedmainlyfromthelongeralkylwithstrongelectron-donatingabilitycanenhancethedelocationdegreeofconjugatedπelectronics.
简介:Bilayerhumidity-responsiveactuatorsaregenerallycomposedofactuatingandsupportinglayersofdifferentmaterialswithlargelydifferentwettability.Suchkindsofbilayeractuatorssufferfromlowadhesiveforcebetweenthetwolayersduringusage.Thisstudydemonstratesthepreparationofhumidity-responsivebilayeractuatorsthathavethesamematerialsintheactuatingandsupportinglayerstoavoidtheadhesiveissue.Thebilayeractuatorsconsistofaporouspoly(acrylicacid)σAA)/poly(allylaminehydrochloride)(PAH)layerandanonporousPAA/PAHlayerthatarefabricatedbyexponentiallylayer-by-layerassemblymethod.Atahigh/lowrelativehumidity(RH),thenonporousPAAIPAHlayercanefficientlyexpand/shrinkbyabsorbing/desorbingwaterwhilethevolumeexpansion/shrinkageoftheporousPAA/PAHlayerinanenvironmentwithchangedhumidityissignificantlysuppressedbythemicrometer-sizedpores.Thelargelydifferentexpansion/shrinkageofthenonporousandporousPAA/PAHlayerswhensubjectedtohumiditychangesenablesrapidandreversiblerolling/unrollingmotionsofthebilayeractuator.Thebilayeractuatorshowsafasterrollingspeedandalargerbendingcurvaturewhensubjectedtoalargerhumidityincrease.
简介:结晶化修正(vinylidene氟化物)(PVDF)poly为PVDF并且poly的混合电影(甲基methacrylate)(PMMA)被调查。集体crystallinity(c)并且进一步,阶段内容(PVDF的F()),与不同集体比率为asprepared混合电影被学习。另外,c和F的变化()一旦PMMA部件从相关混合系统被移开,系统地被探查。DSC,FTIR和XRD大小都显示了那1)c,F()并且甚至阶段的内容(F())与PMMA的增加减少了;2)与PMMA的抽取,c和F()当时,增加了F()减少。它是值得注意的c和F的增加()取决于提取PMMA(EPMMA)的相对数量,即,越多PMMA被移开,越多c和F()增加。这些结果从PMMA成分揭示阻碍者效果到PVDF的结晶化,并且因而,当PMMA被提取时,这限制将被释放。