DQ-1高效催化剂的活性中心分布变化规律

Changes in Active Center Distribution of DQ-1 High Yield Ziegler-Natta Catalyst

用相对分子质量分布分峰拟合方法研究了DQ-1-AlEt3/Ph2Si(OMe)2和DQ-1-Al(i-Bu)3/Ph2Si(OMe)2两种催化体系催化1-己烯聚合的活性中心分布,考察了聚合温度、外给电子体用量、聚合反应时间等因素影响活性中心分布的规律,据此分析了不同活性中心的结构和性质。在DQ-1催化剂的A、B、C、D4种活性中心中,可生成相对分子质量最高的聚合物的A型活性中心稳定性较差,其活性在聚合温度升高、聚合时间延长及给电子体用量增大时明显下降。

The active center distributions in 1-hexene polymerization catalyzed by DQ-1-TEA/ED and DQ-1-TIBA/ED (DQ-1 is a Ti-Mg based high-yield Ziegler-Natta catalyst,ED is external donor) were studied by fitting polymer relative molecular mass distribution curve with multiple Flory functions.The influence of polymerization temperature,ED and polymerization time on active center distribution were investigated. Structures and properties of different type active centers were discussed based on experimental results.Among four types of catalyst active centers,the active centers producing polymer of highest relative molecular mass were least stable; the activity of which decreased sharply with increasing polymerization temperature,polymerization time and amount of ED.