高分子材料納米二氧化硅外文文獻(xiàn)翻譯

納米二氧化硅對(duì)成核、結(jié)晶和熱塑性能的影響外文文獻(xiàn)翻譯(含：英文原文及中文譯文)文獻(xiàn)出處：LaoutidF,EstradaE,MichellRM,etal.Theinfluenceofnanosilicaonthenucleation,crystallizationandtensilepropertiesofPP–PCandPP–PAblends[J].Polymer,2013,54(15):3982-3993.英文原文Theinfluenceofnanosilicaonthenucleation,crystallizationandtensilepropertiesofPP–PCandPP–PAblendsLaoutidF,EstradaE,MichellRM,etalAbstractImmiscibleblendsof80wt%polypropylene(PP)with20wt%polyamide(PA)orpolycarbonate(PC)werepreparedbymeltmixingwithorwithouttheadditionof5%nanosilica.Thenanosilicaproducedastrongreductionofthedispersephasedropletsize,becauseofitspreferentialplacementattheinterface,asdemonstratedbyTEM.PolarizedLightOpticalmicroscopy(PLOM)showedthataddingPA,PCorcombinationsofPA-SiO2orPC-SiO2affectedthenucleationdensityofPP.PAdropletscannucleatePPunderisothermalconditionsproducingahighernucleationdensitythantheadditionofPCorPC-SiO2.PLOMwasfoundtobemoresensitivetodeterminedifferencesinnucleationthannon-isothermalDSC.PPdevelopedspherulites,whosegrowthwasunaffectedbyblending,whileitsoverallisothermalcrystallizationkineticswasstronglyinfluencedbynucleationeffectscausedbyblending.AdditionofnanosilicaresultedinanenhancementofthestrainatbreakofPP-PCblendswhereasitwasobservedtoweakenPP-PAblends.Keywords：Nanosilica，Nucleation，PPblends1OverviewImmisciblepolymerblendshaveattractedattentionfordecadesbecauseoftheirpotentialapplicationasasimpleroutetotailorpolymerproperties.Thetensionisintwoimmisciblepolymerizationstages.Thiseffectusuallyproducesatransferphasebetweenthepressuresthatmayallowthesizeofthedispersedphasetobeallowed,leadingtoimprovedmixingperformance.Blockcopolymersandgraftcopolymers,aswellassomefunctionalpolymers.Forexample,maleicanhydridegraftedpolyolefinsactascompatibilizersinbothchemicalaffinities.Theycanreducethedropletvolumeattheinterfacebypreventingthetwopolymersfromcoalescing.Inrecentyears,variousstudieshaveemphasizedthatnanofillers,suchasclaycarbonnanotubesandsilica,canbeusedasasubstitutefororganicsolubilizersforincompatiblepolymermorphology-stabilizedblends.Inaddition,insomecases,nanoparticlesincombinationwithothersolubilizerspromotenanoparticleinterfaceposition.Theuseofsolidparticle-stabilizedemulsionswasfirstdiscoveredin1907byPickeringinthecaseofoil/emulsioncontainingcolloidalparticles.Intheproductionofso-called"Picklingemulsions",solidnanoparticlescanbetrappedintheinterfacialtensionbetweenthetwoimmiscibleliquids.Somestudieshaveattemptedtoinfertheresultsofblendingwithcolloidalemulsionpolymerblends.Wellmanetal.showedthatnanosilicaparticlescanbeusedtoinhibitcoalescenceinpoly(dimethylsiloxane)/polyisobutylenepolymers.mix.Eliasetal.reportedthathigh-temperaturesiliconnanoparticlescanmigrateundercertainconditions.Thepolypropylene/polystyreneandPP/polyvinylacetateblendinterfacesformamechanicalbarriertopreventcoalescenceandreducethesizeofthedispersephase.Incontrasttotheabovecopolymersandfunctionalizedpolymers,thenanoparticlesarestableattheinterfaceduetotheirdualchemicalnature.Forexample,silicacanaffectnanoparticle-polymeraffinitieslocally,minimizingthetotalfreeenergythatdevelopstowardthesystem.Thenanofillerispreferentiallyplacedinequilibriumandthewettingparameterscanbepredictedandcalculated.Thedifferenceintheinterfacialtensionbetweenthepolymerandthenanoparticlesdependsonthesituation.Thefree-diffusionofthenanoparticle,whichinducesthenanoparticlesandthedispersedpolymer,occursduringthehighshearprocessandshowsthatthelimitationoftheviscosityofthepolymerhardlyaffectstheBrownianmotion.Asaresult,nanoparticleswillexhibitstrongaffinityatthelocalinterfaceduetoviscosityanddiffusionissues.Blockcopolymersneedtochemicallytargetaparticularpolymertothenanoparticlemayprovidea"moregeneric"waytostabilizethetwo-phasesystem.Incorporationofnanosilicamayalsoaffecttheperformanceofotherblends.Toimprovethedistributionanddispersionofthesecondstage,mixingcanproducerheologicalandmaterialmechanicalproperties.Silicaparticlescanalsoactasnucleatingagentstoinfluencethecrystallizationbehavior.Onestudiestheeffectofcrystallinesilicaoncrystallinepolystyrenefilledwithpolybutyleneterephthalate(polybutyleneterephthalate)fibers.Theyfoundastablefibrilcrystallizationratebyincreasingthecontentofpolybutyleneterephthalateandsilica.Ontheotherhand,nosignificantchangeinthemeltcrystallizationtemperatureofthePAwasfoundinthePA/ABS/SiO2nanocomposites.TheblendingofPPwithengineeringplastics,suchaspolyesters,polyamides,andpolycarbonates,maybeausefulwaytoimprovePPproperties.Thatis,improvingthermalstability,increasingstiffness,improvingprocessability,surfacefinish,anddyeability.Thesurface-integratednano-silicaheat-generatingmorphologiesrequirehybridcompatibilizationforthe80/20weightratioofthethermalandtensilepropertiesoftheblendedpolyamideandpolypropylene(increasedperformance).Beforethiswork,somestudies[22]thatis,PAisthemaincomponent).Thisindicatesthattheinterfaciallyconstrainedhydrophobicsilicananoparticlesobstructthedispersedphase;fromthepolymerandallowingarefinementofmorphology,reducingthemixingscalecanimprovethetensilepropertiesofthemixture.Themainobjectiveofthepresentstudywastoinvestigatetheeffectofnanosilicaaloneonthemorphological,crystalline,andtensilepropertiesofmixturesofnanosilicaalone(formixedphaseswithpolypropyleneasamatrixandesterasafiller.Inparticular,PA/PCorPA/nanoTheeffectofSiO2andPC/nanosilicaonthenucleationandcrystallizationeffectsofPPasthemaincomponent.WewereabletostudythedeterminationofthenucleationkineticsofPPandthegrowthkineticsoftheparticlesbymeansofpolarizationopticalmicroscopy.DSCmeasurestheoverallcrystallizationkinetics.Therefore,amoredetailedassessmentofthenucleationandspherulitegrowthofPPwasperformed,however,theeffectofnanosilicaaddedinthesecondstagewasnotdetermined.TheresultwasAkemiandHoffman.AndHuffman'scrystaltheoryisreasonable.2testphase2.1RawmaterialsThepolymerusedinthisstudywasacommercialproduct:isotacticpolypropylenecamefromahomopolymerofpolypropylene.TheFrenchformula(B10FBmeltflowindex2.16Kg=15.6g/10minat240°C)nylon6fromDSMengineeringplastics,Netherlands(AgulonFahrenheittemperature136°C,meltflowindex240°C2.16kg=5.75g/10min)Polycarbonateusedtheproductionwasteofautomotiveheadlamps,itsmeltflowindex=5g/10minat240°Cand2.16kg.ThesilicapowderTS530isfromCabot,Belgium(about2.2ProcessingPP_PAandPP-PCblendsandnanocompositeswerehotmeltmixedinarotatingtwinscrewextruder.Extrusiontemperaturesrangefrom180to240°C.ThesurfacesofPP,PA,andPCwerevacuumizedat80°Candthepolymerpowderwasmixedintothesilicaparticles.Theformedparticleswereinjectedintoastandardtensilespecimenformingmachineat240C(3mmthicknessofD638intheAmericanSocietyforTestingMaterials).Priortoinjectionmolding,allthespheruliteswereinadehumidifiedvacuumfurnace(atatemperatureof80°Covernight).Themoldingtemperaturewas30°C.Themoldwascooledbywatercirculation.Themixtureofthiscombinationisshowninthetable.2.3FeatureDescription2.31TemperaturePerformanceTestAPerkineElmerDSCdiamondvolumethermalanalysisofnanocomposites.Theweightofthesampleisapproximately5mgandthescanningspeedis20°C/minduringcoolingandheating.Theheatinghistorywaseliminated,keepingthesampleathightemperature(20°Cabovethemeltingpoint)forthreeminutes.Studythesample'sultra-highpuritynitrogenandcalibratetheinstrumentwithindiumandtinstandards.Forhightemperaturecrystallizationexperiments,thesamplecoolingrateis60°C/minfromthemeltdirectlytothecrystalreachingthetemperature.Thesampleisstillthreetimeslongerthanthehalf-crystallizationtimeofTc.TheprocedurewasdeducedbyLorenzoetal.[24]afterwards.2.3.2StructuralCharacterizationScanningelectronmicroscopy(SEM)wasperformedat10kVusingaJEOLJSM6100device.Sampleswerepreparedbygoldplatingafterfractureatlowtemperature.Transmissionelectronmicroscopy(TEM)micrographswithaPhilipscm100deviceusing100kVacceleratingvoltage.Ultra-lowcutresectionofthesamplewaspreparedforcutting(LeicaOrma).Wide-AngleX-RayDiffractionAnalysisThesingle-line,Fourier-type,line-type,refinementanalysisdatawerecollectedusingaBRUKERD8diffractometerwithcopperKαradiation(λ=1.5405A).Scatteranglesrangefrom10oto25°.Witharotarystepsweep0.01°2θandthesteptimeis0.07s.Measurementsareperformedontheinjectionmoldeddisc.ThissuperstructuremorphologyandobservationofspherulitegrowthwasobservedusingaLeicaDM2500Ppolarizedlightopticalmicroscope(PLOM)equippedwithaLinkam,TP91thermalstagesamplemeltedinordertoeliminatethermalhistoryafter;temperaturereductionofTCallowedisothermalcrystallizationtooccurfromthemelt.TheformisrecordedwithaLeicaDFC280digitalcamera.Asensitiveredplatecanalsobeusedtoenhancecontrastanddeterminethebirefringenceofthesymbol.2.3.3MechanicalAnalysisTensiletestswerecarriedouttomeasurethestretchrateat10mm/minthroughaLloydLR10Kstretchbenchpress.Allspecimensweresubjectedtomechanicaltestsfor20±2°Cand50±3%relativehumidityforatleast48hoursbeforeuse.Measurementsareaveragedoversixtimes.3results3.1CharacterizationbyElectronMicroscopyItisexpectedthatPPwillnotbemixedwithPC,PAbecauseoftheirdifferentchemicalproperties(polarPPandpolarPC,PA)blendswith80wt%ofPP,andthedropletsandmatrixofPAandPCareexpectedmorphologies[1-4]ThemixtureactuallyobservedthroughtheSEM(seeFigures1aandb).Infact,becausethetwocomponentshavedifferentpolarmixturesthatresultintheformationofanunstablemorphology,ittendstomacroscopicphaseseparation,whichallowsthesystemtoreduceitstotalfreeenergy.Duringshearingduringmelting,PAorPPisslightlymixed,deformedandelongatedtoproduceunstableslenderstructuresthatdecomposeintosmallersphericalnodulesandcoalescetoformlargerdroplets(dropletsareneatintotalThesizeoftheblendis1~4mm.)ScanningelectronmicroscopypicturesandPP-PChybridPP-PAneatandcleandisplayleftthroughtheparticleremovalatcryogenictemperaturesshowingtypicallackofinterfacialadhesionoftheimmisciblepolymerblend.Theadditionof5%byweightofhydrophobicsilicatotheLEDisapowerfulblendofreducedsizeofthedispersephase,ascanbeobservedinFigures1candD.Itisworthnotingthatmostofthedispersedphasedropletsarewithinthesubmicronrangeofinternalsize.Theadditionofnano-SiO2toPAorPCproducesfinerdispersioninthePPmatrix.Fromthepositionalmorphologyresults,wecanseethisdramaticchangeandthepreferentialaccumulationattheinterfaceofsilicananoparticles,whichcanbeclearlyseeninFIG.2.PP,PApartofthesiliconisalsodispersedinthePPmatrix.ItcanbespeculatedthatthisformationofinterphasenanoparticlesaccumulatesaroundthebarrierofthesecondaryphaseoftheLED,thusmainlyformingsmallerparticles[13,14,19,22].Accordingtofenouillotetal.[19]Nanoparticlesaremixedinapolymerlikeanemulsifier;intheendtheywillstablymix.Inaddition,thepreferentiallocationintheintervalisduetotwodynamicandthermodynamicfactors.Nanoparticlesaretransferredtothepreferentialphase,andthentheywillaccumulateintheinterphaseandthefinalmigrationprocesswillbecompleted.Anotheroptionisthatthereisn'tasinglephaseofoptimizationandthenanoparticleswillbesetpermanentlyinphase.Inthecurrentsituation,accordingtoFigure2,thepageisapreferentialphaseandisexpectedtohavepolarpropertiesinit.3.2Wide-anglex-raydiffractionThepolymerandsilicaincorporateasmallamountofnanoparticlestomodifysomeofthemacroscopicpropertiesofthematerialandthetriggeredcrystalstructureofPP.TheWAXDexperimentwasperformedtoevaluatetheeffectoftheincorporationofsilicaonthecrystallinestructureofthemixedPP.Isotacticpolypropylene(PP)hasthreecrystallineforms:monoclinic,hexagonal,andorthorhombic[25],andthenatureofthemechanicalpolymerdependsonthepresenceofthesecrystallineforms.ThemetastableBformisattractivebecauseofitsunusualperformancecharacteristics,includingimprovedimpactstrengthandelongationatbreak.ThefigureshowsacommonformofinjectionmoldingoftheoriginalPPcrystal,reflectingtheappearanceat2θ=14.0,16.6,18.3,21.0and21.7correspondingto(110),(040),(130),(111)and(131)Thefaceisanα-ipp.20%ofthePAincorporationintoPPaffectstherecrystallizationofthecrystalstructureappearingat2θ=15.9°.Thecorresponding(300)surfaceoftheβ-iPPcrystalappearsacertainnumberofβ-phasesthatcanbetriggeredbythenucleationactivityofthePAphaseinPP(seeevidenceThefollowingnucleation)isthefirstinthecrystallineblendofPA6duetoitshighercrystallizationtemperature.Infact,Garbarczyketal.[26]TheproposedsurfacesolidificationcausedbylocalshearmeltsthesurfaceofPA6andPPandformsduringtheinjectionprocess,promotingtheformationofβ_iPP.Accordingtoquantitativeparameters,KX(Equation(1)),whichiscommonlyusedtoevaluatetheamountofB-crystallitesinPPincludingoneandB,thecrystalstructureofβ-PPhas20%PP_PA(110),H(040)andBlendsofH(130)heights(110),(040)and(130).TheheightatH(300)(300)fortypeApeaks.However,theBcharacteristicof5wt%silicananoparticlesincorporatedintothesamehybridLEDeliminatesreflectionandreflectiona-ippretentioncharacteristics.Aswillbeseenbelow,thecombinationofPAandnanosilicainducesthemosteffectivenucleatingeffectofPP,andaccordingtotowaxd,thiscrystalformationcorrespondstoonePPstructurecompletely.Thestrongreductivefracturestrainobservationswhenincorporatedintopolypropyleneandsilicananoparticles(seebelow)cannotbecorrelatedtothePPcrystalstructure.Infact,thetwooriginalPPandPP_PA_SiO2hybridscontainα_PPbuttheoriginalPPhasaveryhighformoffailurewhenthestrainvalue.Ontheotherhand,PP-PCandPP-PC-Sio2blends,throughtheirWAXDmodel,canbeproventocontainonlyone-PPform,whichisaductilematerial.3.3PolarizedOpticalMicroscopy(PLOM)TofurtherinvestigatetheeffectoftheadditionoftwoPAs,thecrystallizationbehaviorofPCandsilicananoparticlesonPP,theX-raydiffractionanalysisofitscrystallinestructureofPPsupplementsthestudyofquantitativeblendsbyusingisothermalkineticconditionsunderapolarizingmicroscope.TheeffectofthecompositiononthenucleationactivityofPPspherulitegrowth._PolypropylenenucleationactivityThenucleationactivityofapolymersampledependsontheheterogeneityinthenumberandnatureofthesamples.Thesecondstageisusuallyafactorintheincreaseinnucleationdensity.Figure4showstwoisothermalcrystallizationtemperaturesforthePPnucleationkineticsdata.ThisassumesthateachPPspherulitenucleatesinacentralheterogeneity.Therefore,thenumberofnascentspherulitesisequaltothenumberofactiveisomerousnuclearpages,onlythenucleus,PP-generatedspherulitescanbecounted,andPPspherulitesareeasilydetected.To,whilethePAorPCphasesareeasilyidentifiablebecausetheyaresecondaryphasesthataredispersedintodroplets.Athighertemperatures(Fig.4a),onlythePPblendinsideiscrystallized,althoughthecrystalsarestillneatPPamorphousattheobservedtime.ThisfactindicatesthatthesecondstageoftheincreasehasbeenabletoproducePP144°C.Itisimpossibletorepeattheporousexperimentinthetimeofsomenon-homogeneousnucleationeventsandneatPPexploration.ThemixedPP-PCandPP-PC-SiO2exhibitedrelativelylowcoredensitiesat144°C,(3105and3106nuc/cm3)suggestingthateitherPCnanosilicacanalsobeconsideredasgoodshapeNuclearagentisusedhereforPP.Ontheotherhand,PA,himself,hasproducedasporadicincreaseinthenumberofnucleatingeventsinPPcomparedtopurePP,especiallyinthelongercrystallizationtime(>1000seconds).InthecaseofthePP-PA_Sio2blend,theheterogeneousnucleationofPPisbyfarthelargestofallsampleinspections.AllthetwostagesofthenucleatingagentcombinedwithPAandsilicaarebestemployedinthiswork.InordertoobservethenucleationofpurePP,alowercrystallizationtemperaturewasused.Inthiscase,observationsathighertemperaturesfoundatrendthatwasroughlysimilar.TheneatPPandPP-PCblendshavesmallnucleationdensitiesinthePP-PC-SiO2nanocompositeandtheincreasealsoaddsfurtherPP-PAblends.TheverylargenumberofPPisoformswasrapidlyactivatedat135°CinthePP-PAnanoparticlenanometerSiO2compositestomakeanyquantificationoftheirnumbersimpossible,sothismixeddatadoesnotexistfromFigure4b.ThenucleationactivityofthePCphaseofPPissmall.ThenucleationofanyPCinPPcanbeattributedtoimpuritiesthataffectthemorecomplexnatureofthePAfromthePCphase.ItisabletocrystallizeathighertemperaturesthanPP,fractionalcrystallizationmayoccurandtheTtemperatureisshiftedtomuchlowervalues??(seeReferences[29-39].However,asDSCexperimentsshowthatinthecurrentcaseThephaseofthePAiscapableofcrystallizing(fashionbeforefractionation)thePPmatrix,andthenucleationofPPmayhaveepitaxyorigin.ThematerialshowninthefigurerepresentsaPLOAMmicrograph.PurePPhastypicalα-phasenegativespherulites(Fig.5A)inthecaseofPP-PAblends(Fig.5B),andthePAphaseisdispersedwithdropletsofsizegreaterthanonemicron(seeSEMmicrograph,Fig.1).WecouldnotobservethespherulitesoftheB-phasetypeinPP-PAblends.EvenaccordingtoWAXD,20%ofthemcanbeformedininjectionmoldedspecimens.ItmustbeborneinmindthatthesamplestakenusingthePLOAMtestwerecutofffromtheinjectionmoldedspecimensbuttheirthermalhistory(direction)wasremovedbymeltingpriortomeltingforisothermalcrystallizationnucleationexperiments.ThePAdropletsaremarkedlyenhancedbythenucleationofpolypropyleneandthenumberofspherulitesisgreatlyincreased(seeFigures4and5).SimultaneouslywiththePP-PAblendofsilicananoparticles,thesharpincreaseinnucleationdensityandFig.5Cindicatethatthesizeofthespherulitesisverysmallanddifficulttoidentify.ThePP-PCblendsshowedsignsofsampleformationduringthePCphase,whichwasjudgedbylarge,irregularlyshapedgraphs.Significanteffects:(a)NocoalescedPCphase,nowoccurringfinelydispersedsmalldropletsand(B)increasednucleationdensity.Asshowninthefigureabove,nano-SiO2tendstoaccumulateattheinterfacebetweenthetwocomponentsandpreventcoalescencewhilepromotingsmalldispersephasesizes.Fromthenucleationpointofview,itisinterestingtonotethatitiscombinedwithnanosilicaandasabetternucleatingagentforPP.CombiningPCswithnanosilicadoesnotproducethesameincreaseinnucleationdensity.Independentexperiments(notshownhere)PP_SiO2samplesindicatethatthenumberofactivecoresat135°CisalmostthesameasthatofPP-PC-SiO2intermixing.Therefore,silicacannotberegardedasaPPnucleatingagent.Therefore,themostlikelyexplanationfortheresultsobtainedisthatPAisthemostimportantreasonforallthematerialsusedbetweenpolypropylenenucleatingagents.TheincreaseinnucleationactivitytoalargeextentmaybeduetothefactthatthesenanoparticlesreducethesizeofthePAdropletsandimproveitsdispersioninthePPmatrix,improvingthePPandPAintheinterfacialblendsystem.Betweentheregions.DSCresultsshowthatnano-SiO2isaddedherewithoutanuclearPAphase.4Conclusion5%weightofpolypropylene/hydrophobicnanosilicablendedpolyamideandpolypropylene/polycarbonate(80E20wt/wt)blendsformapowerfulLEDtoreducethesizeofdisperseddroplets.ThissmallfractionofreduceddropletsizeisduetothepreferentialmigrationofsilicananoparticlesbetweenthephasesPPandPAandPC,resultinginananti-aggregationandblockingtheformationofdropletsofthedispersedphase.TheuseofopticalmicroscopyshowsthattheadditionofPA,theinfluenceofPC'sPA-Sio2orPC-Sio2combinationonnucleation,thenucleationdensityofPPpolypropyleneunderisothermalconditionsisinthefollowingapproximateorder:PP<PP-PC<PP-PC-SiO2<<PP-PA<<<PP-PA-SiO2.PADripNucleationPPProductionofnucleationdensitiesatisothermaltemperaturesishigherthanwithPCorPCSio2D.WhennanosilicaisalsoaddedtothePP-PAblend,thedispersion-enhancedmixingoftheenhancednanocompositesyieldsanintrinsicfactorPP-PA-Sio2blendthatrepresentsaPAthatisidentifiedashavingahighnucleationrate,duetonanosecondsSiliconoxidedidnotproduceanysignificantnucleationPP.PLOAMwasfoundtobeamoresensitivetoolthantraditionalcoolingDSCscanstodeterminedifferencesinnucleationbehavior.TheisothermalDSCcrystallizationkineticsmeasurementsalsorevealedhowthedifferencesinnucleationkineticswerecomparedtothegrowthkineticmeasurements.Blends(andnanocompositesofimmiscibleblends)andmatrixPPspheruliteassembliescangrowandtheirgrowthkineticsareindependent.Thepresenceofasecondaryphaseofdensitycausesdifferencesinthe(PAorPC)andnanosilicanuclei.Ontheotherhand,theoverallisothermalcrystallizationkinetics,includingnucleationandgrowth,stronglyinfluencethenucleationkineticsbyPLOAM.BoththespherulitegrowthkineticsandtheoverallcrystallizationkineticsweresuccessfullymodeledbyLaurieandHuffmantheory.Althoughvarioussimilaritiesinthemorphologicalstructureofthesetwofilledandunfilledblendswereobserved,theirmechanicalpropertiesaredifferent,andthereasonforthiseffectiscurrentlybeinginvestigated.Theadditionof5%byweightofhydrophobicnano-SiO2resultedinbreakingthestrain-enhancementofthePP-PCblendandfurtherweakeningthePP-PAblend.中文譯文納米二氧化硅對(duì)PP-PC和PP-PA共混物的成核，結(jié)晶和熱塑性能的影響LaoutidF,EstradaE,MichellRM,etal摘要80(wt%)聚丙烯與20(wt%)聚酰胺和聚碳酸酯有或沒有添加5%納米二氧化硅通過(guò)熔融混合制備不混溶的共聚物。由于界面上電磁場(chǎng)的位置優(yōu)先,納米二氧化硅能烈的減少分散液滴的大小。偏光光學(xué)顯微鏡顯示了添加PA、PC或組合PA-Sio2對(duì)PP成核密度的影響。添加了PA液滴的聚丙烯的成核密度比相同條件下添加PC或PC-Sio2的成核密度更高。顯微鏡被認(rèn)為比非等溫DSC能更敏感的確定成核的差異。PP的球晶生長(zhǎng)發(fā)達(dá)不受混合物的影響,而其整體等溫結(jié)晶的動(dòng)力學(xué)能強(qiáng)烈的影響成核效應(yīng)引起共混。添加納米二氧化硅導(dǎo)致PP—PC共混物斷裂應(yīng)變的增強(qiáng),而據(jù)觀察削弱了PP-PA共混物斷裂應(yīng)變。關(guān)鍵詞:納米二氧化硅、成核、PP混合物1概述非混相聚合物共混物幾十年來(lái)引起關(guān)注的是鑒于他們潛在的應(yīng)用作為一個(gè)簡(jiǎn)單地路線剪裁聚合物的性能。穩(wěn)定的非混相聚合物混合形態(tài)可以通過(guò)使用增容代替降低界面之間的張力在兩個(gè)非混相聚合階段。這種效應(yīng)通常產(chǎn)生一個(gè)減小分散相的尺寸可能允許的壓力之間的轉(zhuǎn)移階段,導(dǎo)致改善混合性能。嵌段共聚物及接枝共聚物,以及一些功能聚合物。例如,馬來(lái)酸酐接枝聚烯烴在化學(xué)親和力這兩個(gè)段作為增容劑。他們可以在界面通過(guò)防止兩種聚合物聚結(jié),減小液滴的體積。近年來(lái),各種研究都強(qiáng)調(diào)了納米填料,如粘土碳納米管和二氧化硅可以用來(lái)作為一種替代有機(jī)增溶劑對(duì)不相容聚合物形態(tài)穩(wěn)定的共混物。此外,在某些情況下,納米粒子與其他增溶劑組合促進(jìn)界面位置的納米粒子。固體粒子穩(wěn)定乳液的使用,首先被皮克林于1907年發(fā)現(xiàn)油/乳液的情況下含膠體粒子。在生產(chǎn)的,所謂的“皮克林乳液”,固體納米粒子可能被困在界面張上的兩種不混溶的液體之間的界面張力影響。一些研究已經(jīng)試圖推斷出用膠體乳液聚合物共混來(lái)混溶的結(jié)果,韋爾曼特等人表明納米二氧化硅粒子可用于抑制聚結(jié)在聚(二甲基硅氧烷)/聚異丁烯聚合物共混。伊萊亞斯等人報(bào)道高溫硅納米粒子可以遷移,在一定條件下聚丙烯/聚苯乙烯和PP/聚醋酸乙烯酯共混物接口形成一個(gè)機(jī)械屏障防止聚結(jié)從而降低分散相尺寸。與上述共聚物和功能化聚合物相比不同的是,納米顆粒由于其雙化學(xué)性質(zhì)它是穩(wěn)定界面處的。例如,二氧化硅可以在局部影響納米顆?！酆衔镉H和力,使發(fā)展趨向系統(tǒng)的總自由能最小化。優(yōu)先使納米填料處于平衡處,可以預(yù)測(cè)計(jì)算潤(rùn)濕參數(shù)。聚合物和納米粒子之間的界面張力的差異依情況而定。高剪切過(guò)程中發(fā)生熔融處理誘導(dǎo)納米顆粒和分散的聚合物之間的碰撞液滴和出現(xiàn)的主要機(jī)制負(fù)責(zé)進(jìn)入熔體的納米粒子的界面的位移。納米粒子的自由擴(kuò)散展示了由聚合物粘度限制幾乎不影響布朗運(yùn)動(dòng)。結(jié)果是,由于粘度以及擴(kuò)散問(wèn)題,納米粒子將會(huì)在局部接口展示強(qiáng)烈的親和力。嵌段共聚物需要以化學(xué)方法針對(duì)一個(gè)特定的聚合物對(duì)納米顆?？赡芴峁┮粋€(gè)“更通用“的方式穩(wěn)定兩相系統(tǒng)。摻入納米二氧化硅也可能影響其他共混物性能。改進(jìn)分布和分散第二階段的,混合可以產(chǎn)生流變和材料力學(xué)性能。二氧化硅粒子也可以作為成核劑影響結(jié)晶行為。Mei等人研究晶體二氧化硅在結(jié)晶的聚苯乙烯充滿了聚丁烯(對(duì)苯二酸酯)(聚對(duì)苯二甲酸丁二酯)纖維的影響。他們通過(guò)增加聚對(duì)苯二甲酸丁二酯和二氧化硅的含量找到了一個(gè)穩(wěn)定原纖維的結(jié)晶速率。另一方面,對(duì)于PA/ABS/SiO2納米復(fù)合材料在納米二氧化硅相關(guān)內(nèi)容中發(fā)現(xiàn)PA的熔融結(jié)晶溫度沒有顯著的變化。PP與工程塑料共混,如,聚酯,聚酰胺、聚碳酸酯可能是提高PP屬性的一個(gè)有用的方法。也就是,改善熱穩(wěn)定性,增加剛度,改善加工性能,表面光潔度和可染性。為增強(qiáng)性能需要混合增容。在這之前工作,一些研究[22]表明整合納米二氧化硅發(fā)熱形態(tài)對(duì)80/20重量比混合的聚酰胺和聚丙烯的熱性能和拉伸性能的影響(也就是,PA是主要成分)。這表明界面約束的疏水性二氧化硅納米粒子阻礙了分散相;從聚合物和允許一個(gè)形態(tài)學(xué)的細(xì)化,減少混合的尺度能夠改善混合物的拉伸性能。目前研究的主要目的調(diào)查單獨(dú)的納米二氧化硅(沒有添加聚合物增溶劑)對(duì)非混相以聚丙烯聚合物為基體,(以一個(gè)固定的占80wt%的聚合物組分)包含PA或聚碳酸酯作為填料的混合物在形態(tài)上、結(jié)晶和拉伸性能的影響。特別是添加了PA/PC或PA/納米二氧化硅和PC/納米二氧化硅以PP為主要成分在成核和結(jié)晶效果的影響。我們能夠通過(guò)偏振光光學(xué)顯微鏡想、研究確定PP的成核動(dòng)力學(xué)以及球粒的生長(zhǎng)動(dòng)力學(xué)。而采用DSC測(cè)量整體結(jié)晶動(dòng)力學(xué)。因此,對(duì)PP的成核和球晶生長(zhǎng)進(jìn)行一個(gè)詳細(xì)的評(píng)估,然而第二階段添加的納米二氧化硅的影響沒有確定。結(jié)果是阿基米和Hoffman和霍夫曼結(jié)晶理論是合理的。2試驗(yàn)階段2.1原材料本研究中使用的聚合物是商業(yè)產(chǎn)品:等規(guī)聚丙烯來(lái)至聚丙烯的均聚物。法式(B10FB熔體流動(dòng)指數(shù)在240℃時(shí)2.16Kg=15.6g/10min)尼龍6來(lái)源于DSM工程塑料,荷蘭(阿古隆華氏溫度136℃,熔體流動(dòng)指數(shù)在240℃時(shí)2.16㎏=5.75g/10min)聚碳酸酯采用了汽車前照燈的生產(chǎn)廢料,它的熔體流動(dòng)指數(shù)=5g硅石粉TS530來(lái)自卡博特,比利時(shí)(每225㎡/g平均顆粒(骨粒)約200—300nm的長(zhǎng)度,以后稱為二氧化硅是一種疏水性硅土經(jīng)氣相法合成六甲基二硅烷與硅醇反應(yīng)在粒子表面。2.2加工PP_PA和PP-PC混合物和納米復(fù)合材料在一個(gè)旋轉(zhuǎn)雙螺桿擠出機(jī)中進(jìn)行熱熔混合。擠壓溫度范圍從180到240℃之間擠壓。PP、PA、PC的表面在真空80℃和聚合物粉末被混入二氧化硅粒子。形成的顆粒在240℃被注入標(biāo)準(zhǔn)的抗拉試樣的成型機(jī)中(美國(guó)試驗(yàn)材料學(xué)會(huì)中D638的厚度為3毫米)。注射成型之前,所有的球晶都在除濕的真空爐中,(在80℃2.3特性描述2.31溫度性能的測(cè)試一個(gè)PerkineElmerDSC金剛石量熱議對(duì)納米復(fù)合材料的分析。樣品的重量大約5mg和掃描速度為20℃/min在冷卻和加熱過(guò)程中。加熱歷史被消除,保持樣品在高溫(峰熔點(diǎn)以上20對(duì)于高溫結(jié)晶實(shí)驗(yàn),樣品冷卻速度為60℃2.3.2結(jié)構(gòu)表征掃描電子顯微鏡(SEM)進(jìn)行分析在10kV使用JEOLJSM6100裝置。制備樣品通過(guò)低溫?cái)嗔押箦兘稹鬏旊娮语@微鏡(TEM)的顯微照片與飛利浦cm100裝置使用100個(gè)千伏的加速電壓。樣品的TEM進(jìn)行超cryomicrotomy準(zhǔn)備切割(徠卡歐爾馬)。廣角X射線衍射分析單線傅氏線型精煉分析法數(shù)據(jù)收集使用BRUKERD8衍射儀與銅Κα輻射(λ=1.5405A)。散射角范圍為10o~25°。與一個(gè)旋轉(zhuǎn)步驟掃0.01°2θ和步驟時(shí)間為0.07s。測(cè)量進(jìn)行注塑光盤。這個(gè)superstructural形態(tài)學(xué)和球晶生長(zhǎng)觀察使用徠卡DM2500p偏振光光學(xué)顯微鏡(PLOM)配備一個(gè)Linkam,TP91熱階段的樣品熔融為了消除后,熱歷史;溫度的降低TC允許等溫結(jié)晶從熔體發(fā)生。形態(tài)用徠卡DFC280數(shù)碼相機(jī)記錄。一個(gè)敏感的紅色板還可用于增強(qiáng)對(duì)比度和確定符號(hào)的雙折射。2.3.3力學(xué)分析進(jìn)行拉伸試驗(yàn)測(cè)量通過(guò)勞埃德LR10K拉伸板凳機(jī)在拉伸率的10毫米/分鐘。所有標(biāo)本使用機(jī)械測(cè)試之前進(jìn)行條件事20±2℃3結(jié)果3.1通過(guò)電子顯微鏡形貌表征預(yù)計(jì)PP將不與PC、PA混合因?yàn)樗麄兊牟煌幕瘜W(xué)性質(zhì)(極性PP和極性的PC、PA)共混物與80wt%的PP,PA和PC的液滴與基體是預(yù)期的形態(tài)[1—4]實(shí)際上觀察到的情況通過(guò)SEM整齊的混合物(見圖1a和b)。事實(shí)上,因?yàn)檫@兩個(gè)組件具有不同的極性混合物會(huì)導(dǎo)致形成不穩(wěn)定的形態(tài),它傾向于宏觀相分離,這一過(guò)程允許系統(tǒng)減少它的總自由能。在融化過(guò)程中的剪切作用下,PA或PP輕微混合,變形和拉長(zhǎng)到產(chǎn)生不穩(wěn)定的細(xì)長(zhǎng)結(jié)構(gòu)分解為較小的球形結(jié)節(jié)和凝聚形成更大的水滴(液滴在整潔的共混物的大小是1~4mm)掃描電鏡的圖片和PP-PC混合PP-PA整潔干凈的顯示離開通過(guò)粒子去除在低溫?cái)嗔扬@示典型的缺乏界面粘附的非混相聚合物混合。5%重量的疏水性二氧化硅的加入LED是一個(gè)強(qiáng)大的共混物分散相的尺寸減少,可以觀察到在圖1c和D。值得注意的是,大多數(shù)的分散相液滴的亞微米范圍內(nèi)的大小。納米SiO2的加入PA或PC在PP基體中產(chǎn)生的更精細(xì)的分散。從位