摘要
用光学显微镜观察了六种聚丙烯试样熔体在非等温结晶过程中形态织构的变化。并且与在同样条件下试样结晶过程中观察到的声发射现象进行对照。证实聚丙烯熔体结晶过程中产生声发射讯号主要是在结晶后期,特別是球晶生长结束并形成边界后,在球晶边界和球晶内部形成微缺陷的过程所导致的。它与球晶形成时体积收缩、内应力的产生和增加直接有关。
The transformation of morphology and texture of polypropylene melt duringnon-isothermal crystallization has been continuously observed by optical microscope and hasbeen compared with the results of acoustic emission(AE)at the same cooling rate.During thelate stage of crystallization the impingement of sphrulites leads to the formation ofinterspherulites boundaries,the volume shrinkage of spherulites resulted from the density in-creasing by crystallization causes the stress arising on the boundaries and inside the spherulites.When the stress is abruptly released,acoustic waves are emitted and microcavities and cracksoccure.
基金
国家自然科学基金
9287006
关键词
声发射
聚丙烯
结晶
acoustic emission
polypropylene
non-isothermal crystallization
spherulite
