2005%20高分子研討會(huì)ppt.ppt

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1、Y.H.Wen(溫玉合)andC.C.Hua(華繼中)DepartmentofChemicalEngineering,NationalChungChengUniversityATheoreticalandExperimentalInvestigationonShort-TimeStretchRelaxationofEntangledPolymerSolutionsIntroductionHistoricalSketchdeGennes(1971)DoiandEdwards(1986)Thetub

2、e(orreptation)modelanditsderivativeshaveprovenverysuccessful,especiallyindescribingthelinearviscoelasticityofentangledpolymerliquidsLinearrelaxationChainRetraction(nonlinearrelaxation)AStoryaboutNonlinearViscoelasticityOrientationRelaxation(linearrel

3、axation)PS/DEPsolution(Mw=5.5x106g/mol;PI=1.01;Zeq=77)ChainRetraction(nonlinearrelaxation)DilutesolutionConcentratedsolutionRousechainObjectivesofthecurrentinvestigation:TheRouseModelPredictiononShort-timeChainRetractionNonlinearStressRelaxationDatai

4、nSingle-stepStrainFlowsFortimescales

5、eand:shearstress:D-Euniversalfunction(w/oIAassumption):plateaumodulus:strain:tubesurvivalprobability:dimensionlesschainstretching:No.ofRousemodes:No.ofentanglementsperchainatequilibriumNonlinearstressrelaxationmodulus:ExperimentallyDeterminedModelPar

6、ametersNumberofentanglementsperchainatequilibrium,TheRousetime,φ:volumefractionofpolymerPS/TCPsolutionTheory/DataComparisonsPS/DEPsolutionPS/DEPsolutionSelf-consistentlyRenormalizedRouseModes(a)t=0(atequilibrium)Adifferentnumberofentanglementsperchai

7、n?NisadynamicvariableARenormalizedRousemodel:where(b)t=0+StretchingRetraction(c)t

8、nglementpropertyhasasignificantimpactonshort-timechainretractionofentangledpolymersolutions.Self-consistentmoderenormalizationleadstobetteragreementwithexperimentaldata.Remainingdiscrepanciesmightresultfrom(a)Inaccuracyofshort-timerelaxationdataand/o