Synthesis of high molecular weight polyethylene using FIcatalyst

AFI Zr-based catalyst of bis[ was prepared and used for polymerization of ethylene. The effects of reaction conditions on the polymerization N-(3,5-dicumylsalicylidene)-2′,6′-diisopropylanilinato]zirconium(IV) dichloridewere examined in detail. The increase in ethylene pressure and rise in polymerization temperature up to 35°C werefavorable for catalyst/MAO to raise the catalytic activity as well as the viscosity-average molecular weight (Mv)of polyethylene. The activity of the catalyst was linearly increased with increasing MAO concentration and nooptimum activity was observed in the range studied. Although introduction of the bulky cumyl and 2′,6′-diisopropylalkyl substitution groups on ortho positions to the phenoxy-oxygen and on phenyl ring on the N, respectivelyenhanced the viscosity average molecular weight (Mv) of the obtained polymer strongly, diminished the activityof the catalyst. Neither the activity of the catalyst nor the (Mv) of the obtained polymer were sensitive to hydrogenconcentration. However, higher amount of hydrogen could slightly increase the activity of the catalyst. The (Mv)of polyethylene ranged from 2.14×106 to 2.77×106 at the monomer pressure of 3 and 5 bar, respectively which aremuch higher than those of the reported FI Zr-based catalysts. Polyolefns J (2014) 1: 25-32

Keywords:

FI catalyst , high molecular weight , polyethylene , ethylene polymerization