Ti,Al改性Phillips乙烯聚合催化剂的结构及性能研究

Ti, Al modified phillips chromium catalysts and their catalytic performance for ethylene polymerization

通过添加钛(Ti)、铝(Al)对Cr/SiO_(2) Phillips催化剂进行改性,制备出了Cr-Ti/SiO_(2)和Cr-Ti-Al/SiO_(2)两种改性催化剂,考察了改性催化剂的结构及催化乙烯聚合性能。结果表明,添加Ti和Al后,催化剂表面变得粗糙,孔径变小,比表面积增大;催化活性增加,最高活性分别为55.36和82.55g(PE)/g(Cat),而Cr/SiO_(2)仅为45.39g(PE)/g(Cat)。改性催化剂的PE产品分子链变长,结晶度增加,高分子量组分增多,分子量分布变宽。

Two modified Phillips catalysts for ethylene polymerization,Cr-Ti/SiO_(2) and Cr-Ti-Al/SiO_(2) were prepared by adding titanium(Ti)and aluminum(Al)into the Cr/SiO_(2) catalyst.The structure and catalytic performance of the modified catalysts were investigated.The results showed that,the particles of catalysts doping with Ti and Al elements,become more rough,decreasing in pore diameter and increasing in specific surface area.And it is more active for catalysing ethylene polymerization,the highest activity of Cr-Ti/SiO_(2) and of Cr-Ti-Al/SiO_(2) are 55.36g(PE)/g(Cat)and 82.55g(PE)/g(Cat).Respectively,compared that of Cr/SiO_(2) is 45.39g(PE)/g(Cat).The PE products with the modified catalysts contains more long chain portion,higher crystallinity;and wider molecular weight distribution.