Nature of Strain-Induced Crystallization in Synthetic Poly-isoprene by In-Situ Synchrotron X-ray Study (Paper No.20)

摘要

Dynamic (strain-induced) crystallization and static (temperature- or time-induced) crystallization of poly-isoprene rubbers have been studied by simultaneous in-situ synchrotron X-ray and mechanical measurements. The deformed samples at high stretching ratio clearly exhibited strain-induced crystallization. Upon stretching, the deformed sample kept at a constant strain exhibited stress relaxation or stress build-up depending on temperature. The decrease in temperature or isothermal annealing reduced the stress significantly by promoting static crystallization. In contrast, the increase in temperature increased the bulk stress even though some strain-induced crystallites became melted. The different contributions in stress by static and dynamic crystallization processes will be discussed in this study.