新型聚丙烯催化剂的性能研究

根据气相法生产均聚双向拉伸聚丙烯的特点,制备了定向能力易于随助催化剂与外给电子体的摩尔比(铝硅比)变化而调节的NA-Ⅱ型Ziegler-Natta聚丙烯催化剂。对比了NA-Ⅱ型催化剂与其他两种参比催化剂的组成、形态和粒径,并研究了铝硅比对催化剂定向能力的影响。分别以二异丁基二甲氧基硅烷和二异丙基二甲氧基硅烷为外给电子体对NA-Ⅱ型催化剂及两种参比催化剂的均聚和共聚性能进行了研究。实验结果表明,NA-Ⅱ型催化剂具有较好的颗粒形态,氢调敏感性较好,聚丙烯的等规度易于调控。

Study on Property of New Polypropylene Catalyst

A new Ziegler-Natta catalyst—NA-Ⅱcatalyst was developed aiming at its adaptability to features of present installation for gas-phase polymerization of propylene and flexibility to produce bioriented polypropylene.Comparisons were made between NA-Ⅱcatalyst and other two reference catalysts in terms of specifications,morphology and particle size,etc..The stereospecific ability of NA-Ⅱcatalyst was studied by changing mole ratio of A1 to Si(mole ratio of cocatalyst to external donor).The properties of the three catalysts in homopolymerization and copolymerization were also studied by using different external donors,namely diisobutyl dimethoxysilane and diisopropyl dimethoxysilane.NA-Ⅱcatalyst is regular in particle morphology and sensitive in hydrogen responsibility.The isotacticity of product polypropylene is easily adjusted by controlling mole ratio of Al to Si.