氢气、外给电子体及聚合温度对iPP微观结构的影响

Effect of hydrogen, external electron donor and polymerization temperature on microstructure of isotactic polypropylene

用工业非均相Ziegler-Natta催化剂通过实验室制备和工业生产获得等规聚丙烯(i PP),利用高温凝胶渗透色谱仪、差示扫描量热仪等对i PP进行分析表征。在聚合温度分别为60,70℃条件下,研究了H2、外给电子体环己基-甲基-二甲氧基硅烷(CHMMS)对i PP相对分子质量及其分布、立构规整性及结晶性能等的影响。结果表明:H2,CHMMS对i PP微观结构的影响与聚合温度有很大关系;在不加CHMMS、聚合温度为60℃时,加入H2使i PP全同立构五单元组序列结构含量从60.16%增至77.45%;H2和CHMMS通过影响丙烯分子的"头-头"或"头-尾"结合方式对i PP的微观立体缺陷分布有调整作用。

Isotactic polypropylene（iPP） produced with an industrial heterogeneous Ziegler-Natta catalyst in lab and on industrial scale was characterized by high temperature gel permeation chromatography（GPC）, differential scanning calorimetry（DSC）,etc. The effects of hydrogen and external electron donor cyclohexyl methyl dimethoxy silane（CHMMS） on the relative molecular mass and its distribution,stereoregularity and crystallization property of iPP were investigated at the polymerization temperature of 60,70 ℃. The results show that the influences of hydrogen and CHMMS on the microstructure of iPP depend on the polymerization temperature greatly. The content of stereoregularity pentad sequence structure is increased from 60.16% to 77.45% by adding hydrogen without CHMMS at 60 ℃. Hydrogen and CHMMS regulate the three-dimensional micro-defect distribution of iPP by influencing head-head or head-tail combination way of propylene molecules.