Effects of propylene prepolymerization on ethylene/1-hexene and ethylene/1-octene copolymerization with an immobilized metallocene catalyst

The impacts of propylene prepolymerization on ethylene/1-hexene and ehylene/1-octene copolymerization studies carried out with a catalyst comprising a zirconocene and MAO immobilized on a silica support were analyzed. The copolymerization of samples, following the prepolymerization, was carried out by the charging of the desired amount of the comonomer to the reactor, along with n-heptane and an ethylene pressure applied. The catalyst used was prepared by the impregnation of a silica support with a mixture of MAO and rac-Et/(Ind) 2ZrCl2. Results show that the application of a propylene prepolymerization was significantly increased in the subsequent ethylene polymerization. Also, the prepolymerization of a silica-supported metallocene catalyst with propylene before ethylene/1-hexene or ethylene/1-octene copolymerization can lead to a narrowing of the CCD in the resulting copolymers.