Supported metallocene catalysts for ethylene polymerization

摘要

Polymerizations of ethylene were carried out with SiO_2 - supported Cp_2ZrCl_2 catalyst in toluene at 50 °C. Several kinds of heterogeneous catalysts were prepared and an experimental design was elaborated in order to find the best preparing conditions of these catalysts. Silica gel for catalyst support was calcinated before used and for some catalysts, pretreatment with methylaluminoxane (MAO) at different concentrations was carried out. The molecular weight, molecular weight distribution, melting point and crystallinity of the obtained polymers and also the polymerization behavior such as catalytic activity were examined.