Combined metallocene catalysts: an efficient technique to manipulate long-chain branching frequency of polyethylene

The solution polymerization of ethylene in Isopar E in a semi-batch reactor using combined CGC-Ti and EtInd]₂ZrCl₂ catalysts was studied. Methylaluminoxane (MAO) and tris(pentafluorophenyl)borane were used as co-catalysts. Samples were analyzed by ¹³C NMR and gel permeation chromatography (GPC) for their branching content and molecular weight distribution. It was shown that there was an optimum ratio of CGC-Ti/EtInd]₂ZrCl₂ that maximizes the number of long-chain branches of the formed polyethylene.