Morphology Control and Performance of Crystalline Polymers by drawing under Supercritical Fluids

我们设计了一个拉伸测试系统，在其中我们可以测量超临界流体下的聚合物薄膜的应力-应变行为。结晶聚合物在超临界CO_2条件下增塑，拉伸性能得到改善。在不同温度和压力的CO_2气体中进行拉伸，可以得到各种性能的高分子材料。超临界CO2高温拉伸使聚丙烯的结晶度和熔融温度提高，而低温拉伸使聚丙烯的密度降低，形成纳米有序的孔洞。通过小角X射线散射和电子显微镜的结果讨论了由此获得的特征形貌的进展。

We designed a tensile testing system in which we can measure the stress-strain behavior of polymer films under supercritical fluids. The crystalline polymers were plasticized and the drawability was improved under supercritical CO_2. Polymer materials with various properties could be obtained by drawing under CO_2 at various temperatures and CO_2 pressures. Crystallinity and melting temperature of polypropylene were increased by drawing at high temperature under supercritical CO_2, while nano-ordered voids were formed and the density decreased by drawing at low temperature under CO_2. The progress of the characteristic morphologies thus obtained was discussed by the results of small-angle x-ray scattering and electron microscope.