硅胶负载型烯烃聚合催化剂的研究 Ⅴ 化学活化对催化剂相结构和聚合动力学的影响

用ＸＲＤ手段对硅胶负载型气相聚乙烯催化剂的相结构受化学活化的影响进行了研究，在一定范围内三乙基铝的加入量对热活化硅胶载体相结构影响很小，所制备的催化剂仍为非晶型，当三乙基铝的加入量超过脱除热活化硅胶表面剩余羟基所需量较大时，催化剂表面会形成微量的络合结晶物，这些微量结晶物使催化剂的聚合效率明显降低。聚合动力学实验表明，没有经过化学活化的催化剂聚合动力学为快速衰减型且聚合活性很低，只有通过使用适当三乙基铝配比的化学活化后才能获得动力学平稳的高效催化剂

STUDIES ON SILICASUPPORTED POLYOLEFIN CATALYSTS EFFECTS OF CHEMICALACTIVATION ON CATALYSTS PHASE STRUCTURE AND ETHYLENEPOLYMERIZATION KINETICS

In the UNIPOL ethylene gas phase polymerization processes, the chemicalactivation process of support would affect the properties of the catalysts significantly. In this paper, the effects of chemicalactivation on catalysts phase structure have been studied by XRD method. Within certain amount of AlEt3, chemicalactivation would not change the thermoactivated silica supports phase structure. When the amount of AlEt3 surpass the corresponding amount for dehydroxylation of the thermoactivated silica, a little amount of crystallized complex occurred, and it will result in the decrease of the catalyst activity. Without chemicalativation step the polymerization kinetics appeared as a fast decay type, and the activity is also very low. Only with proper chemicalactivation process could the catalyst get high efficiency as well as stationary acceleration type of kinetics.