摘要
研究了流延聚丙烯高温下的应力-应变行为,在特定的实验条件下捕捉到了应力波动,即应力随应变的增大而发生复杂波动的现象。通过试样拉伸前后结构的DSC和WAXD表征,发现拉伸后试样的熔融行为和结晶结构都发生较大的变化,因此认为应为波动主要与高温条件下拉伸过程引起的试样的应力诱导结晶有关。为了避免应力波动,提高拉伸速率时,应使共聚物的序列分布均匀,即乙烯链能均匀地插入丙烯主链中,打乱丙烯链段的连续性,以降低结晶速率和结晶度,实现高速稳态拉伸。
The stress-strain behavior of cast polypropylene(CPP) at elevated temperature was investigated, and the complexstress oscillation phenomenon, i. e. the complicated fluctuation of the stress with the increasing of strain under some special conditions, was captured in stress-strain curves of the CPP samples. The structures of samples before and after stretching were characterized by Differential Scanning Calorimetry (DSC) and Wide Angle X-ray Diffraction ( WAXD). The resulting melting behavior and crystalline structure were found to change greatly. It is believed that the stress oscillation was caused by stress-induced crystallization. For higher production rate and preventing the stress oscillation, it is necessary to control the distribution of commonomer sequences to lower the crystallization rate and crystallinity and achieve high speed stable production of CPP films.
出处
《工程塑料应用》
CAS
CSCD
北大核心
2002年第12期37-39,共3页
Engineering Plastics Application
基金
国家重点基础研究专项经费资助项目(G1999O64805)
关键词
应力波动
挤出成型
流延聚丙烯
高温应力-应变行为
cast polypropylene, stress-strain behavior, stress oscillation, high temperature
