【摘要】 为了研究Ziegler-Natta催化剂的多活性中心催化特性和动力学特性,进行了在其作用下的丙烯/1-丁烯共聚实验,估算了单体表观竞聚率以反映共单体插入能力,聚合物分子量分布去卷积成Flory组分,提出用双活性中心模型描述聚合过程中的丙烯消耗速率。结果表明,随1-丁烯初始进料浓度的提高,聚合活性先降低后增高;聚合物分子量随1-丁烯初始进料浓度的提高而降低、随聚合时间的延长而略微升高。五活性中心的Flory分布函数足够描述聚合物分子量分布,根据动力学特性将催化体系内活性中心分成两类,该双活性中心模型可以很好地描述聚合过程中丙烯消耗速率,也吻合分子量分布去卷积计算出的组分质量分率。更多还原

【Abstract】 Copolymerization of propene/1-butene was studied to investigate the multicenter catalytic characteristics and kinetic characteristics of Ziegler-Natta catalysts. Apparent monomer reactivity ratios were estimated as a reflection of co-monomer incorporation ability, and molecular weight distributions(MWDs) of the polymers were deconvolved into Flory components. A two-site-type kinetic model was proposed to describe propene consumption rates. The results show that the polymerization activity decreases first and then increases with the increase of 1-butene concentration. The molecular weights of the polymers decrease with the increase of 1-butene concentration and increase with the increase of polymerization time. Flory distribution functions with five active center types can adequately describe polymer MWDs, and the active centers in the catalyst can be classified into two types in terms of kinetic characteristics. The proposed two-site-type kinetic model can well fit the propene consumption rates and the mass fractions of the Flory components in MWD deconvolution.更多还原