聚丙烯中英文对照外文翻译文献

中英文对照外文翻译(文档含英文原文和中文翻译)CrystallizationBehaviorsofLinearandLongChainBranchedPolypropyleneABSTRACT:Thenonisothermalcrystallizationkineticsoflinearandlongchainbranchedpolypropylene(LCBPP)wereinvestigatedbydifferentialscanningcalorimetry(DSC)atvariouscoolingrates.SeveralmethodssuchasAvrami,Ozawa,andJeziornywereappliedtodescribethecrystallizationprocessoflinearPPandLCBPPswithdifferentLCBlevelundernonisothermalconditions.Thevaluesoft1/2,Zc,andF(T)showthatLCBhastheroleofheterogeneousnucleatingagentandacceleratesthecrystallizationprocessofPP.Moreover,theKissingermethodwasusedtoevaluatetheactivationenergyoflinearPPandLCBPPs.TheresultshowsthattheactivationenergyofLCBPPsarehigherthanthatoflinearPP,indicatingthatthepresenceofLCBbafflesthetransferofmacromolecularsegmentsfromPPmelttothecrystalgrowthsurface.Furthermore,thecrystalmorphologyoflinearPPandLCBPPswasobservedthroughpolarizedopticalmicroscopy(POM),andfinespheruliteswereobservedforLCBPPs.Keywords:polypropylene;longchainbranch;nonisothermalcrystallization;kineticINTRODUCTIONIsotacticpolypropylene(iPP)hasmanydesirableandbeneficialphysicalpropertiessuchaslowdensity,highmeltingpoint,andchemicalresistance.Therefore,iPPhasbeenusedwidelyinindustrialandcommercialapplications.However,iPPisalinearpolymer,asaresult,itexhibitslowmeltstrengthandnostrainhardeningbehaviorinthemeltstate,whichlimitsitsuseinapplicationssuchasthermoforming,foaming,andblowmolding.ThemosteffectivemethodtoimprovethemeltstrengthofPPistointroducelongchainbranching(LCB)ontothePPbackbone.TherehasbeenconsiderableinterestintherelationshipsbetweenLCBmoleculararchitectureandrheologicalbehaviorofPPintherecentyears.ThechangeofmoleculararchitecturecanaffectnotonlyrheologicalpropertybutalsocrystallizationpropertyofPP.However,thecrystallizationbehavioroflinearandlongchainbranchedpolypropylene(LCBPP)hasseldombeenstudiedindetail.TherehavemanystudiesonthecrystallizationofgraftedPP.ItiswidelyacceptedthatgraftedPPpartlyactsasanucleatingagentforthematrixandacceleratesthecrystallizationrate.speculatedthatthedifferentcrystallizationbehaviorbetweenPP-g-MAandPPisduetoachaininteraction,suchashydrogenbondingbetweenhydrolyzedmaleicanhydridegroups.ThereisnospecificdefinitionaboutLCB,however,fromrheologicalviewpoint,thelengthnecessaryforabranchtobehaveasalongchainbranchis2Me(Memolecularweightbetweenentanglements).Therefore,themoleculararchitecturesforgratedPPandLCBPPareverydifferent.Asaresult,thecrystallizationbehaviorandcrystalmorphologyofLCBPPwillbedifferentfromlinearPPorgraftedPP.ItcanbeconcludedfromlimitedliteraturesthatLCBPPhashighercrystallizationtemperature,shortercrystallizationtime,andbroadermeltingrangewhencomparedwithlinearPP.

Inourpreviousstudy,LCBPPswithdifferentLCBlevelwerepreparedbymeltgraftinginthepresenceofperoxideandpolyfunctionalmonomer,andtheirlinearviscoelasticpropertieswerealsostudied.ThepurposeofthisarticleistoinvestigatethenonisothermalcrystallizationkineticsofLCBPPswithdifferentLCBlevelcomparedwithlinearPP.Severalnonisothermalcrystallizationkineticequationswereused.Thenecessarydatawereobtainedfromdifferentialscanningcalorimetry(DSC)thermogram.ThekineticparameterssuchastheOzawaexponentandtheactivationenergieswerecalculated.Inaddition,thecrystalmorphologyoflinearPPandLCBPPswasalsostudiedbypolarizedopticalmicroscopy(POM).SamplepreparationLCBPPswithdifferentLCBlevelwerepreparedbymeltinggraftinginthepresenceof2,5-dimethyl-2,5(tbutylperoxy)hexaneperoxideandpentaerythritoltriacrylate(PETA)polyfunctionalmonomerinmixerat1808C;thedetailsofthepreparationprocessandcharacterizationbyrheologymethodswerediscussedinRef.15.Theformulation,zero-shearviscosity,andLCBlevelofsampleswerelistedinTableI,whereZ0andLCB/104Cweredeterminedbyrheologymethod.LCBlevelofD3cannotbecalculatedaccuratelybecauseitslongerrelaxationtimeislargerthanthemaximumrelaxationtimethatcanbedeterminedfromourexperiments.However,itcanbeconfirmedthatLCBlevelofD3ishigherthanthatofD2.DifferentialscanningcalorimetryThermalanalysisofthesampleswascarriedoutwithadifferentialscanningcalorimeter(DSC)instrumentundernitrogenatmosphere.Tostudythecrystallizationandmeltingbehaviors,thesamplesabout4mgweremeltedat2008Cfor5mintoeliminatethermalhistory,followedbycoolingatarateof108C/minandthecrystallizationthermogramwasmeasured.Thetemperatureofpeakswastakenasthecrystallizationtemperature,Tc.Assoonasthetemperaturereached508C,itwasreheatedagainatarateof108C/minandthemeltingthermogramwasmeasured.Theprocedurefornonisothermalcrystallizationwasasfollows:thesamplesweremeltedat200Cfor5mintoeliminatethermalhistory,andthencooledtoroomtemperatureat5,10,20,30,and40oc/min,respectively.TheexothermalcurvesofheatflowasafunctionoftemperaturewererecordedtoanalyzethenonisothermalcrystallizationprocessofPPandLCBPPs.PolarizedopticalmicroscopyAsamplewassandwichedbetweentwomicroscopecoverglasses,meltedat2008Cfor5mintoeliminatethermalhistory,andthencooledtoroomtemperatureat208C/min.RESULTSANDDISCUSSIONCrystallizationandmeltingbehaviorofPPandLCBPPsFigure1(a,b)showscoolingandheatingthermogramsofPPandLCBPPs,andthecorrespondingcrystallizationandmeltingparametersdeterminedfromFigure1aregiveninTableII.ItcanbeseenfromcoolingthermogramsinFigure1(a)thatthecrystallizationtemperatures(Tc)ofLCBPPsarehigherthanthatofPP.AsshowninTableII,TcofPPis115.38CandTcofD1,D2,andD3is130.8,132.0,and132.18C,respectively.ItisclearthatthepresenceofLCBstructuremakesTcofPPimprovemorethan158C,however,TcincreasesslightlywithLCBlevel.Furthermore,incaseofLCBPPs,asmallshoulderonthecoolingthermogramscanbeobserved.ItcanbebelievedthattheshoulderrelatedtothepresenceofLCBstructure,whichwillbediscussedlater.ThesubsequentreheatingthermogramsofPPandLCBPPsareshowninFigure1(b).Themeltingtemperature(Tm)andtheenthalpiesoffusion(DHm)arealsolistedinTableII.ItcanbeseenthatthethermogramsforPPandLCBPPsallshowedsinglemeltingpeak.TmofLCBPPsshifttohighertemperaturecomparedwiththatofPP,moreover,theshapeofmeltingpeaksforLCBPPsisbroaderthanthatofPP,whichsuggeststhatthecrystallinesofPParemoreperfectthanthatofLCBPPs.ThecrystallinityofPPcanbedeterminedfromheatingscansusingthefollowingequations:ThecrystallinityofPPandLCBPPswascalculatedbyeq.(1)andthedatawerelistedinTableII.AsshowninTableII,thecrystallinityofLCBPPsishigherthanthatofPP,indicatingthatthebranchedchainscanactasanucleatingagentandhelptoincreasethecrystallinityofPP.NonisothermalcrystallizationbehaviorofPPandLCBPPsFigure1showsthenonisothermalcrystallizationexothermalcurvesofPPandLCBPP(sampleD2)atdifferentcoolingrates.Someusefulparameterssuchastheonsetcrystallizationtemperature(To),thepeaktemperature(Tp),andtheendcrystallizationtemperature(Te)canbeobtainedfromthesecurves,andthevalueswerelistedinTableIII.Asexpected,theexothermicpeakshiftedtolowertemperatureandbecamebroaderwithcoolingrateincreasingforallsamples.AsshowninTableIII,TpofLCBPPsishigherthanthatofPPatgivencoolingrate,indicatingthatthecrystallizationrateincreasedandthedegreeofsupercoolingrequiredforthecrystallizationreducedwhenLCBwasintroducedontoPPbackbone.Moreover,atthegivencoolingrate,TpincreasedslightlywithLCBlevelincreasing;however,italmostdoesnotchangeagainwhenLCBlevelachievedagivenvalue,i.e.,D2.Inaddition,asmallshoulderappearedontheLCBPPscoolingcurvesatlowertemperatureandbecameunconspicuouswiththeincreasingcoolingrate.Toourknowledge,thisphenomenonwasnotreportedinotherlinear,grafted,orbranchedpolymers.Theexactreasonwasnotknown,butitcanbecertainthattheshoulderisrelatedtothepresenceofLCBstructure,whichinfluencesthecrystallizationkineticprocessofPP.Thisphenomenonwillbediscussedinfollowinganalysisofnonisothermalcrystallizationkineticparameters.ObservationofcrystalmorphologybyPOMThecrystalmorphologyofPPandLCBPPswasobservedthroughPOM.Figure9showsthepolarizedmicrographsofPPandLCBPPsnonisothermalcrystallizedatacoolingrateof208C/min.ThelinearPPshowswell-definedspheruliteswitha‘‘Maltesecross’’structure,whereasLCBPPsshowmorenucleationsitesandverytinycrystallites,indicatingthatLCBstructureactsasanucleatingagent.ItcanbeobservedthattheintroducingofLCBacceleratedthenucleation,buttheradialgrowthrateofthespherulitesdecreased.Thisobservationagreeswiththeanalysisaboutnonisothermalkineticparameters.Ontheotherhand,itwasobservedthatthespheruliticdevelopmentofPParisefromsporadicnucleation,whilethatofLCBPParisefrominstantaneousnucleation.Homogeneousnucleationstartsspontaneouslybychainaggregationbelowthemeltingpoint,whichrequiresalongertime,whereasheterogeneousnucleationformssimultaneouslyassoonasthesamplereachesthecrystallizationtemperature.23Consideringtheabove-mentionedkineticanalysis,itcanbeconcludedthatLCBPPcrystallizesmainlyviaheterogeneousnucleation,whilePPcrystallizesviabothheterogeneousnucleationandhomogeneousnucleation.CONCLUSIONSThenonisothermalcrystallizationkineticsoflinearPPandLCBPPswereinvestigatedsystematicallybytheDSCtechnique.Theresultsshowthatatvariouscoolingrates,theexothermicpeaksofLCBPPsdistinctlyshiftedtohighertemperaturescomparedwiththatoflinearPP.TheAvrami,Jeziorny,Ozawa,andMomethodscandescribethenonisothermalcrystallizationprocessoflinearPPandLCBPPverywell.TheAvramiexponentnofLCBPPsissmallerthanthatoflinearPPatvariouscoolingrate,indicatingthattheintroducingofLCBinfluencesthemechanismofnucleationandthegrowthofPP,moreover,thecoolingratehasweakeffectonthevalueofnforLCBPPscomparedtolinearPP.ThevalueofZcforLCBPPsishigherthanthatforlinearPPandthevalueoft1/2forLCBPPsislowerthanthatforlinearPP,suggestingthatthebrancheshavetheroleofheterogeneousnucleatingagentandacceleratedthecrystallizationprocess.TheactivationenergyDEoflinearPPandLCBPPswascalculatedusingKissingermethod.TheresultshowsthatthevaluesofDEforLCBPPsarehigherthanthatforPP,indicatingthatthepresenceofLCBbaffledthetransferofmacromolecularsegmentsfromPPmelttothecrystalgrowthsurface.Moreover,thevalueofDEdecreaseslightlywithLCBlevelincreasing.ThecrystalmorphologyofPPandLCBPPswasobservedthroughPOM.TheresultsshowthatthespherulitesofLCBPPsaremuchsmallerthanthatofPP,indicatingthatLCBstructureactsasnucleatingagent.

线性和长链支化聚丙烯的结晶行为摘要:线性和长链支化聚丙烯的非等温结晶动力学(LCBPP)在不同冷却速率下进行了差示扫描量热法(DSC)。有几种方法，比如阿夫拉米，小泽一郎和Jeziorny描述线性PP的结晶过程和LCBPPs在非等温条件下的不同LCB水平。而t1/2和F(T)的值表明，LCB异质成核剂的作用,加速PP的结晶过程。此外,基辛格的方法被用来评估线性PP和LCBPPs的活化能。结果表明,LCBPPs的活化能高于线性页，LCB挡板的存在从PP熔体高分子领域的转移到晶体生长的表面。此外,线性PP和LCBPPs的晶体结构是通过偏振光学显微镜观察(POM)和细观察LCBPP球晶得来的。关键词:聚丙烯、长链分支、非等温结晶动力学简介等规聚丙烯(iPP)有许多可取的和有益的物理特性,如低密度、高熔点、耐化学性。因此,iPP已经广泛应用于工业和商业应用。然而,iPP是线型高分子,因此,它不显示在融化状态下的低熔体强度和应变硬化行为,这限制了它的使用在应用程序如热成型、发泡、吹塑。最有效的方法来改善PP的熔体强度是引入长链分支(LCB)到PP骨干。近年来对LCB分子结构之间的关系和PP的流变行为有相当大的兴趣。分子结构的变化不仅会影响流变性质也影响PP的结晶属性。然而,线性和长链支化聚丙烯的结晶行为(LCBPP)很少被详细研究。有许多研究是关于接枝PP的结晶。人们普遍认为接枝PP部分矩阵作为成核剂能够加速结晶率。推测PP-g-MA和PP之间的不同的结晶行为是由于链相互作用,如氢键之间水解马来酸酐组。对LCB没有具体的定义,然而,从流变学的观点来看,一个分支行为所需的长度作为一个长链分支2Me。因此,PP碎片的分子结构和LCBPP是非常不同的。因此,LCBPP的结晶行为和结晶形态不同于线性聚丙烯或接枝PP。它可以从有限的文献总结得知,LCBPP的结晶温度高,结晶时间短,与线性PP相比有更广泛的范围融化。在我们先前的研究中,LCBPPs与LCB不同的水平是由于融化嫁接在过氧化氢的存在和多官能团单体决定的,同时对线性粘弹性性能也进行了研究。本文的目的是调查的非等温结晶动力学LCBPPs和不同水平的LCB与几种非等温结晶动力学方程的线性关系。从差示扫描量热法(DSC)热法得到必要的数据。以及小泽等动力学参数指数和激活能量的计算。此外,也研究了线性PP的晶体结构和LCBPPs偏振光学显微镜(POM)。样品制备LCBPPs与不同水平的LCB被融化嫁接前的准备，将tbutylperoxy，己烷和季戊四醇，PETA多官能单体在180oc混合器中混合;制备过程的细节和特征流变学方法过讨论了,zero-shear粘度、和LCB水平的样本是列在表一。LCBD3水平无法准确计算,因为它再弛豫时间大于最大弛豫时间可以确定从我们的实验。然而,它可以证实,LCBD3水平是高于D2。差示扫描量热法在氮气环境中对热分析的样品进行了差示扫描量热计(DSC)仪器。研究结晶和熔融行为,4毫克样品在200oc下大约融化5分钟,消除热历史,紧随其后的是10oc/分钟的速度的冷却和结晶热法的测量。温度峰值作为结晶温度,Tc。当温度达到50摄氏度时,它又以10oc/分钟的速度进行加热和熔化热法的测量。非等温结晶的过程如下:样本用5分钟在200oc下融化来消除热历史,然后在5、10、20、30和40oc/分钟分别冷却到室温。热流的放热曲线作为温度的函数记录分析聚丙烯的非等温结晶过程和LCBPPs。偏振光学显微镜线性PP和LCBPPs的晶体结构研究用偏光显微镜。样本被夹在两个显微镜盖眼镜,用5分钟在200oc下融化来消除热历史,然后以20oc/分钟冷却到室温。结果与讨论PP的结晶和熔融行为和LCBPPs图1(a,b)显示PP和LCBPPs冷却和加热温谱图,相应的结晶和熔融参数在表二与图1给出决定。从冷却热分析图可以看出图1(a),LCBPPs的结晶温度(Tc)是高于PP。如表二所示,PP的Tc是115.3oc而D1、D2、D3分别是130,132和132.1oc,