Thestraininducedcrystallizationbehaviourinpolyimidefrom1,4-bis(3’,4’-dicarboxyphenoxy)benzeneand4,4’-oxydianiline(PEI-E)hasbeeninvestigatedbyWAXD,DSCandFTIR.TheresultsobtainedshowthatcrystallizationinPEI-Edidtakeplacejustaftertensileyielding.Meanwhile,theeffectofstraininducedcrystallizationonthethermomechanicalpropertieswasstudiedbyDMAandTMA,theresultsofwhichindicatethatthecrystallizationandhotstretchinghaveacertaininfluenceonthedynamicmechanicalproperties,suchasweakeningtheβrelaxationanddecreasingtheglasstransitiontemperature.TheTMAresultsconfirmtheshiftingofglasstransitiontemperaturetolowertemperatureregionafterhotstretching.ThisphenomenoncouldbewellexplainedbytheeffectofresidualstressaccordingtoEyring’stheory.
