摘要
在100℃高温时,采用MgCl2负载的Ziegler-Natta催化剂合成了聚丙烯。用核磁共振碳谱、示差扫描量热和X射线衍射等方法对聚丙烯的规整性、结晶过程和形态进行了表征。表征结果显示,聚丙烯等温结晶过程原生晶型有3种形态:α晶型,α和β混合晶型或α和γ混合晶型;当聚丙烯等温结晶过程只生成α晶型时,聚丙烯的规整性与结晶速率成线性关系,规整性越高,结晶速率越快;当聚丙烯等温结晶过程中有β或γ晶型生成时,其结晶速率比相同规整性的只有α晶型的聚丙烯的结晶速率快。
Isothermal crystallization behavior of polypropylenes （PP） prepared with MgCl2 supported Ziegler-Natta catalyst system at high polymerization temperature （100℃ ） was studied mainly by DSC. Structure and morphology of PP were also investigated with temperature rising elution fractionation and characterized by means of 13C NMR and XRD. Three different crystal phases are possible present when PP is crystallizing from the melt： a crystal form only, mixture of α and β crystal forms and mixture of α and γ crystal forms. Isothermal crystallization studies showed that crystallization rate of PP increased linearly as a function of average isotactic sequence length （MRL） when PP contained crystals of a form only. However, crystallization rate of PP, in which β-PP crystals or T-PP crystals appear, is faster than that with only α crystals, even though they have same MRL value.
出处
《石油化工》
CAS
CSCD
北大核心
2009年第6期640-644,共5页
Petrochemical Technology
基金
东莞市科技计划项目(2006018)
关键词
聚丙烯
规整性
结晶动力学
晶型
polypropylene
isotacticity
crystallization kinetics
crystal form
