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,,(,510640):,,:;;:TQ320.65:B:1001O9278(2003)08O0079O04MeltStrengthofPolymersandItsMeasurementTechnologyZHANGuo2rong,ZHOUNan2qiao,PENGXiang2fang(NationalEngineeringResearchCenterofNovelEquipmentforPolymerProcessing,TheKeyLaboratoryofPolymerProcessingEngineering,MinistryofEducationofChina,SouthChinaUniversityofTechnology,Guangzhou510640,China)Abstract:Somefactorsaffectingmeltstrengthareanalysedsuchaspolymerstructurefactorsincludingmeltindex,longchainbranching,comonomertypeandmolecularweightdistributionandmeasuringconditionsincorporatingtemperature,extrusionrateanddrawdistance.TwomeasurementmethodsforpolymermeltstrengthbyusingGottfertRheotensmeltstrengthtesterandmeltindextesterarestressedandthelatterisverifiedthroughexperimentsthatitisasimpleandviablewaytomeasurethemeltstrengthofpolymers.Moreover,byusinganewkindofprocessingtechnologytheelectromag2neticdynamicextrusiontechnology,thepolymermeltstrengthcanbereinforced.Keywords:polymer;meltstrength;measurementtechnology(),,,,,,,,:2003O06O10(29904001),(20003013),,,,[1,2],:,,PP,,Throne[3]:PP143166,,,;,,(),178Vol.17,No.820038CHINAPLASTICSAug.,2003PPPP[4]1[5]1.1,,,1.2,,,,PE2LDPE2LLD4,1.3,-,,,,,,1.4(MFR),,PE2HD,,(),,PE2LDPE2LDPE2LD22.1[6],,[7],,,,,,[6]:log(MS)=E/RT+logCMSCE,Jmol-1R,8.314J(molK)-1T,K,,2.2[6],,[8](,),,,,2.3[9]:,33.11Fig.1ExperimentalarrangementforrheotensmeasurementsBrabenderRheomexGottfertRheotens,1,80,,[9],[1]3.2[10]PE1906min,,,3min,,5%,22190PEFig.2CorrelationsbetweenthemeltstrengthsofPEmeasuredbythedrop2weightmethodandbythemelttensileflowmethod(Rosandprecision)at190:MS()=0.024MS()1.72R2=0.997,PE2mLLDPE2LD,,4,,3min,,,1PE2mLLDPE2LD1,,31PE2mLLDPE2LD()Tab.1ThemeltstrengthofPE2mLLDandPE2LDatdifferenttemperature(bythedrop2weightmethod)/180190200210PE2mLLD/g0.35650.30710.28010.2696PE2LD/g0.46990.36780.34110.3198PE2mLLDPE2LD3PE2mLLDPE2LD()Fig.3ThemeltstrengthofPE2mLLDandPE2LDvs.temperature(bythedrop2weightmethod)PE2mLLDPE2LD4PE2mLLDPE2LD()Fig.4ThemeltstrengthofPE2mLLDandPE2LDvs.temperature(bythemelttensileflowmethod)3PE2mLLDPE2LD,:()=0.024()1.72,,434,20038814,,,55Fig.5Schematicdiagramofscrewspulseinthedirectionofaxesandcircumference,,,,5,,,,,,,:[1]J.M.DealyandK.F.Wissbrun.MeltRheologyandItsRoleinPlasticsProcessing[M].VanNostrandReinhold,NewYork,1990.[2]H.H.Winter.CollaborativeStudyontheRelationBetweenFilmBlowingPerformanceandRheologicalPropertiesofTwoLow2DensityandTwoHigh2DensityPolyethyleneSamples[J].PureandAppliedChemistry,1983,55:943.[3]J.L.Throne.Thermoforming[M].HanserPublishers,Munich,1987.[4]J.J.Morad.HighMeltStrengthPolypropyleneforLargePartThermoforming[R].ANTEC95,1995:783.[5]ShivendraK.Goyal.TheInfluenceofPolymerStructureonMeltStrenghBehaviorofPEResins[J].PlasticsEngineer2ing,1995,51(2):25.[6]H.C.Lau.S.N.Bhattacharya.andG.J.Field.MeltStrengthofPolypropylene:ItsRelevancetoThermoforming[J].PolymerEngineeringandScience,November,1998,38(11):19151923.[7]A.C.Y.Wong.V.H.K.Cheung.ElongationalStrengthofPolyethylenemelt[J].JournalofMaterialProcessingTech2nology,1997,67:117119.[8]C.D.Han.RheologyinPolymerProcessing[M].AcademicPress.NewYork,1976.[9]S.Muke,etal.ExtensionalRheologyofPolypropyleneMeltsfromtheRheotensTest[J].JournalofNon2NewtonianFluidMechanics,2001,101:7793.[10]KAMHO,etal.MeltStrengthofLinearLow2densityPolyethylene/Low2densityPolyethyleneBlends[J].JournalofAppliedPolymerScience,2002,85:14081418.82