气相法钛系乙烯聚合催化剂的研究──催化剂性质、颗粒形态对乙烯气相聚会及产物颗粒形态的影响

研究了研磨法(CM型)和结晶沉淀反应法(MG－2型)制备的2种乙烯聚合钛系载体催化剂.CM型催化剂含钛3.4％～4.0％,三价钛占总钛含量15％～25％,比表面积为130m₂/g,催化剂活性为9.20kgPE/gTi·h,聚合反应衰减快.MG－2型催化剂含钛7.0％～8.0％,三价钛占总钛含量55％～69％,比表面积为78m₂/g,催化活性为4.45kgPE/(gTi·h),聚合反应衰减慢,反应平稳.对催化剂和聚合产物的扫描电镜和图象分析研究发现,催化剂颗粒小,颗粒分散度小,则聚会产物颗粒及颗粒分散度就小;反之亦然.当CM型和MG－2型催化剂平均粒径(D_av)和颗粒分散度(D_avmax/D_avmin)分别为6.8、33μm和9.2、7.0时,相应聚合产物平均粒径和颗粒分散度分别为155、263μm和10.8、9.0.结果表明,聚合产物颗粒形态复现催化剂颗粒形态。

Studies on Ti-Mg Supported Catalysts for the Gas-Phase Polymerization of Ethylene-The Influence of Properties and Morphology of Particle of Catalyst on the Gas-Phase Polymerization of Ethylene and the Morphology of the Product

Two kinds of Ti-Mg supperted catalysts for gas-phase polymerization of ethylene were studied.The Ti³⁺ content in the milling-made catalyst (CMtype) containing titanium 3-4%-4.0% by mass is 15%-25% of the total titanium.The surface area of the catalyst and catalytic activity for the polymerization are 130m²/g and 9.20 kg PE/(gTi.h).The polymerization showed quickly decaying kinetics.The Ti³⁺ content in the reacting-made cat-alyst(MG-2 type) containing titanium 7.0%-8.0% by mass is 55 %-69% of the total tita-nium.The surface area of the catalyst and catalytic activity are 78 m²/g and 4.45 kgPE/(gTi.h).The polymerization was relative steady.The average value of diameter (D_av) and D_avmax/D_avmin of the CMand MG-2 catalyst particles are 6.8 pm, 33 pm and 9.2, 7.0, respec-tively, and corresponding values of polymerization product PEparticles are 155μm, 263μm,and 10.8, 9.0, respectively.The results indicated that the morphology of the polymerization product reproduced that of the catalyst particle.