简介:Anewpreparationmethodhasbeendevelopedforthermallystableporouspolyimidemicrospheres.Porouspolyimidemicrosphereswerepreparedusingtriblockcopolymersthatconsistedofathermallystablepolyimidederivedfrompyromelliticdianhydride/4,4’-oxydianilineasthecontinuousphaseandathermallylabilepolyetherasthedispersedphase.Spheresofcopolymersweregeneratedinanonaqueousemulsionandthengraduallyheatedtocompletetheimidizationtoformamicrophase-separatedstructure.Subsequently,thermaltreatmentataslightlyreducedpressureremovedthelabileblocksandproducedpores.Undersuitabledecompositionconditions,theporesizeoftheporouspolyimidewasintherangeof200-400nm.
简介:Tensiledeformationandfracturecharacteristicsofpolyimide/montmorillonitenanocompositefilmsareinvestigatedtoenhancetheparticularmechanicalpropertiesandunderstandtheeffectivefactorsindominatingthemechanicalpropertiesofnanocomposites,suchasthenanolayer,matrixandnanolayer/matrixinterface.Howtocontributetothemechanicalpropertiesofnanocompositefilmisaverycomplexproblem.Inthispaper,thesefactorsareanalyzedbasedontheadditionamountandfracturemechanics.Theresultsindicatethatthespecimenat20wt%MMTbreaksprematurelywithafracturestrength(σb=78MPa)muchlowerthanthat(σb=128MPa)atthe1wt%MMT.However,theYoung'smodulus(3.2GPa)oftheformerishigherthanthat(1.9GPa)ofthelatter.Fractographyalsoindicatesthatthebrittlecrackingformedinhighcontentadditionisthemaincauseoffailurebutmicroscopicallyductilefracturemorphologystillexistslocally.Andforthetraceelementaddition,thesmallerthreadingslippingveinsareevenlydistributedontheentirefracturesectionofthesefilms.Therefore,thesecharacteristicswouldpresumablybeassociatedwithboththeconcentrationeffectsofsizeofnanocompositesheetsandtheincreasingdeformationharmonyinnanolayers.
简介:以便降低polyamic酸(泛美航空公司)的imidization温度,治好的代理人p-hydroxybenzoic酸(公众房产管理局)的催化活动,喹啉(QL),benzimidazole(双性人),benzotriazole(BTA),triethylamine(et3N)并且1,8-diazabicyclo[5.4.0]undec-7-ene(DBU)在泛美航空公司的热imidization的过程被调查。另外,热稳定性和结果的polyimide(PI)的机械性质上的这些各种各样的治好代理人的效果拍摄被决定。喹啉被发现是在为综合的二拍子的圆舞方法的使用的一台有效治好加速器PI。由于它的中等基础力量,低位的拥挤效果和中等沸腾点,喹啉不能仅仅加速泛美航空公司在180点完全完成imidization?
简介:Thestraininducedcrystallizationbehaviourinpolyimidefrom1,4-bis(3’,4’-dicarboxyphenoxy)benzeneand4,4’-oxydianiline(PEI-E)hasbeeninvestigatedbyWAXD,DSCandFTIR.TheresultsobtainedshowthatcrystallizationinPEI-Edidtakeplacejustaftertensileyielding.Meanwhile,theeffectofstraininducedcrystallizationonthethermomechanicalpropertieswasstudiedbyDMAandTMA,theresultsofwhichindicatethatthecrystallizationandhotstretchinghaveacertaininfluenceonthedynamicmechanicalproperties,suchasweakeningtheβrelaxationanddecreasingtheglasstransitiontemperature.TheTMAresultsconfirmtheshiftingofglasstransitiontemperaturetolowertemperatureregionafterhotstretching.ThisphenomenoncouldbewellexplainedbytheeffectofresidualstressaccordingtoEyring’stheory.
简介:Inthispaper,polyimide(PI)filmsaremodifiedusinganatmosphericpressureplasmageneratedbyadielectricbarrierdischarge(DBD)inargon.SurfaceperformanceofPIfilmanditsdependenceonexposuretimefrom0sto300sareinvestigatedbydynamicwatercontactangle(WCA),fieldemissionscanningelectronmicroscopy(FESEM),andFouriertransforminfraredspectroscopyinattenuatedtotalmultiplereflectionmode(FTIR-ATR).ThestudydemonstratesthatdynamicWCAexhibitsaminimumwith40splasmatreatment,andevenlydistributednano-dotsandshadowconcavesappearedfor40sand12sArplasmatreatmentindividually.AshortperiodofplasmamodificationcancontributetothescissionoftheimideringandtheintroductionofC-OandC=O(-COOH)bydetailedanalysisofFTIR-ATR.
简介:Anovelbiphenylside-chaineddiaminewithalkyloxyspacerandalkyloxytail,4'-butoxy-4-(3,5-diaminobenzoyloxy)hexyloxybiphenyl(C6BBC4),wassynthesizedandcharacterizedbyFTIRand1HNMR.Aseriesofpolyimide(PI)filmswithdifferentsidechaincontentswassynthesizedfrombiphenyltetracarboxylicdianhydride(BPDA),4,4'-oxydianiline(ODA)andC6BBC4,andtheirthermalproperties,opticaltransparencyandliquidcrystalalignmentproperty,andsoon,wereinvestigatedbythermogravimetricanalysis(TGA),differentialscanningcalorimetry(DSC),crystalrotationmethod,polarizingmicroscopyandUV-Visspectra.Withthecontentofsidechaineddiamineincreasingfrom0to100%,theηinhofpoly(amideacid)(PAA)decreasedrapidlyfrom3.0to0.51,theglasstransitiontemperature(Tg)ofpolyimides(PIs)decreasedfrom274℃to203℃andtheVis-lighttransmittanceofalignmentfilmssubstantiallyincreased.Asforthealignmentproperties,thepretiltangleofPIalignmentfilmswithoutrubbingcouldreach90°whenthecontentofC6BBC4was60%ormore.Atthesametime,thealignmentstabilitycouldmeettheindustrialrequirements.Itwasconsideredthatthealkoxyspacer,thebiphenylunitandthealkoxytailmayallplayimportantrolesinachievingalargepretiltangleevenupto90°,andtheintroductionofonlythealkoxyspaceroralkoxytailcanalsoimprovethepretiltangle,butnotbymuch.
简介:Inordertoimprovethenonlinearopticalpropertyandstabilityofazo-dyechromophore,thenonlinearopticalpolyimide(NLOPI)attachedwithazochromophoresidechainissynthesizedbydiazocouplingreactionof4-nitrobenzenediazoniumtetrafloroborate.Thedesignedchemicalstructureofproductioncanbeprovedintheinfraredspectrumandultraviolet-visibleabsorptionspectrum.TheNLOPIexhibitedUV-Visabsorptionoftheazobenzenechromophoreinthevicinityofthewavelengthsof330and490nm.ThebroadamorphouspeakprovedthattheNLOPIwasamorphouswithalittleperiodicalstructurealongthesidechain.Accordingtotransmissionelectronmicroscope,theNLOPIfilmwashomogeneous.NLOPIonlydisplayedadecreaseinmassofabout5%atthetemperatureof400℃throughthermogravimetricanalysis.
简介:UsingCu-phthalocyanine(CuPc),4,4'-diaminodiphenyletherandpyromelliticdianhydrideasmonomermaterials,polyimide(PI)thinfilmsdoped-CuPchavebeenpreparedontoglasssubstratebyvaporphaseco-depositionpolymerizationunderavacuumof2×10-3Paandthermalcuringofpolyamicacidfilminattemperatureof150-200Cfor60min.Inthisprocess,thepolymerizationcanbecarriedoutthroughcontrollingthestoichiometricratio,heatingtimeanddepositionratesofthethreemonomers.IRspectrumidentifiesthedesignedchemicalstructureofthepolymer.Theabsorptionofpolyimidedoped-CuPcisveryintenseinvis-rangeandnear-infraredbyUV-Visspectrum.And,thePIfilmsdoped-CuPcpolymerizedbyvaporphasedepositionhaveuniformity,finethermalstabilityandgoodnonlinearopticalproperties,andthethird-orderopticalnonlinearsusceptibilityx(2)withdegeneratefour-wavemixingcanbe1.984×10-9ESU.
简介:WefabricatepolycrystallineCu(In,Ga)Se2(CIGS)filmsolarcellsonpolyimide(PI)substrateattemperatureof450°Cwithsingle-stageprocess,andobtainapoorcrystallizationofCIGSfilmswithseveralsecondaryphasesinit.Forimprovingitfurther,thetwo-stageprocessisadoptedinsteadofthesingle-stageone.AnextraCu-richCIGSlayerwiththethicknessfrom100nmto200nmisgrownonthesubstrate,andthenanotherCu-poorCIGSfilmwiththicknessof1.5-2.0μmisdepositedonit.Withthemodificationoftheevaporationprocess,thegrainsizeofabsorberlayerisincreased,andtheadditionalsecondaryphasesalmostdisappear.Accordingly,theoveralldeviceperformanceisimproved,andtheconversionefficiencyisenhancedbyabout20%.
简介:Thestructureofpolyimidefrom1,4-bis(3’,4’-dicarboxyphenoxy)benzeneand4,4’-oxydianilinefilmspecimensbeforeandafterhotstretchinghasbeeninvestigatedbyWAXD,DSCandFTIR.AsevidencedbyboththeWAXDandDSCresults,itcouldbebelievedthatstraininducedcrystallizationdidtakeplaceafterhotstretching.Meanwhile,shiftingpositionandsplittingofsomebandpeaksexistedontheFTIRspectrogramswereexplainedintermsoftheclosepackingofchainsandthechangesofinter-molecularcharge-transferinteractionbetweenimidegroupsandaromaticgroupsuponcrystallization.
简介:Opticallyactive(R)-(+)-2,2’-bis(2-trifluoro-4-aminophenoxy)-1,1’-binaphthylwaspreparedfrom1,1’-bi-2-naphthol.Theopticallyactivearomaticpolyimidewasalsosuccessfullysynthesized.Thisnewpolymerhasgoodsolubility,thermalstabilityetc.Itsspecificrotationwasfoundtobe+174°,anditschiropticalpropertywasalsostudied.