聚乙烯催化剂PCG-01的制备及性能评价

以乙氧基镁为载体,烷氧基硅烷为给电子体,制备出Mg-Ti系乙烯聚合Ziegler-Natta催化剂PGC-01。研究了该催化剂的聚合反应动力学、氢调敏感性和共聚性能,考察了催化体系Al/Ti摩尔比、聚合温度等工艺条件对催化剂聚合性能的影响,并采用SEM,DSC等分析方法对催化剂和聚合产物的颗粒形态及性能进行了表征。结果表明,该催化剂具有颗粒形态好,粒径分布窄,活性高,聚合产物堆密度高,反应平稳,氢调敏感性良好的特点;以AlEt3为助催化剂,在n(Al)/n(Ti)为120、压力为0.8 MPa、温度为80℃、反应时间为2 h的条件下,催化剂PCG-01的乙烯聚合活性达37.2 kg/g;聚合产物具有近球形结构,粒径主要分布在180～425μm。

Preparation and properties evaluation of polyethylene catalyst PCG-01

Mg- Ti based Ziegler- Natta supported catalyst PGC -01 for ethylene polymerization was prepared with Mg （OEt）2 as carrier and novel alkoxy silanes as electron donor. The polymerization kinetics,hydrogen response and copolymerization behavior of the catalyst were examined. The influences of mole ratio of Al to Ti and polymerization process conditions, such as temperature and time on properties of the catalyst were investigated. The particle morphology of catalyst and polymer product as well as the properties of product were characterized by SEM and DSC respectively. The results showed that the catalyst had good particle morphology, narrow particle size distribution, high polymerization activity,high bulk density of polymer product, steady reaction behavior and good hydrogen response. With A1Et3 as cocatlyst, under the optimal conditions of mole ratio of A1 to Ti 120,total pressure 0.8 MPa, temperature 80 ℃ and time 2 h,the activity of cata- lyst PCG - 01 could reach 37.2 kg/g, the polymer particle had a sphere - like spherical structure, and its diameters mainly distributed in 180-425 μm.