论文部分内容阅读
Real time synchrotron wide angle and small angle X-ray scattering (WAXS and SAXS,respectively) were used to characterize the stretch induced structural evolution of αtrans-1,4-polyisoprene (trans-PI).2D WAXS results indicated two ensembles of crystalline modifications with distinctive orientation modes coexisted during stretching.Stretching transformed part of the monoclinic α phase into highly oriented orthorhombic β phase at strain ε=~0.4.The β phase had rather high orientational degree with polymer chains parallel to the stretching direction,while the orientational degree of α phase was much lower.Complemented by qualitative 2D SAXS analysis,it was found that amorphous layer deformation and intralamellar chain slip dominated at different stretching stage.The melt and recrystallization process of α phase which led to the formation of βphase was also investigated.Formation of two interpenetrating networks of crystalline skeleton (constructed by residual α and β crystals) and amorphous entanglement accounted for the stress-hardening in the late stage.