高效乙烯淤浆聚合催化剂的制备及其性能

制备了一种高效乙烯淤浆聚合催化剂MgCl_2-TiCl_4-Tin(OEt)_4;考察了制备条件对该催化剂性能的影响,并与商品催化剂(BCH)对比了催化剂的粒径分布和聚合物的颗粒形态;考察了MgCl_2-TiCl_4-Ti(OEt)_4催化乙烯均聚及乙烯与1-己烯共聚的性能。研究结果表明,载钛温度对MgCl_2-TiCl_4-Ti(OEt)_4催化剂性能的影响至关重要;MgCl_2-TiCl_4-Ti(OEt)_4催化剂的颗粒形态优于BCH催化剂,聚乙烯中的细粉含量显著降低,聚乙烯的粒径分布更集中;共聚单体1-己烯的加入使共聚物的密度和熔点同时降低,共聚物中的细粉含量低于BCH催化剂制备的共聚物;H_2的加入提高了聚乙烯的熔体流动指数,降低了聚乙烯的熔点,增加了聚乙烯的结晶焓。

Preparation and Performance of Polyethylene Catalyst for Slurry Process

A ethylene polymerization catalyst MgCl_2-TiCl_4-Ti(OEt)_4 for the slurry process was prepared.Effects of the reaction conditions on performance of the catalyst were studied.Compared with the commercial BCH catalyst,particle size distributions of both the prepared catalyst and the polymers,and the performances of the catalyst in both ethylene homo-polymerization and ethylene copolymerization with n-hexene were discussed.The results indicated that the temperature of loading Ti obviously affected the performance of the catalyst.Morphology of the catalyst MgCl_2-TiCl_4-Ti(OEt)_4 was better than that of the BCH catalyst,the fine powder content in the product polyethylene was lower and its particle size distribution was narrower.Addition of the co-monomer n-hexene lowered the polyethylene density and its melting point.Introduction of hydrogen reduced melting point of the product polyethylene,and heightened its melting index and crystal enthalpy.