超临界二氧化碳作用下含β成核剂等规聚丙烯的结晶行为

Influence of Supercritical Carbon Dioxide on Crystallization Behavior of Isotactic Polypropylene with β-Nucleating Agent

研究了含有β成核剂等规聚丙烯在CO2环境中的结晶行为。分别使用X射线衍射仪、差示扫描量热仪及红外光谱仪研究了样品中的β晶含量和β晶的热稳定性。结果表明,相对于常压N2环境,在CO2环境中生成的β晶在升温熔融过程中没有发现β-α重结晶现象,这意味着CO2环境中生成的β晶更稳定。而随着CO2环境中降温速率增大,结晶过程不完善,生成的β晶不稳定,升温熔融过程中逐渐发生了β-α重结晶现象。

The influence of supercritical carbon dioxide(scCO2)on the crystallization behavior of isotactic polypropylene with β-nucleating agent was studied.XRD,DSC and FT-IR were employed to investigate the crystal content and the thermal stability of the β-form in iPP.The results show that the β-αrecrystallization never happens for the β-form crystal obtained in CO2 environment,indicating that the β-form created in CO2 is more stable than that in N2.With the cooling rate increasing,the crystallization in CO2 is not perfect,which would lead to the unstable β-form crystal and hence the β-α recrystallization during the melting process.