Preparation Of Low Molecular Weight Polyethylene By Coordination Chain Transfer Method

Molecular weight polyethylene were synthesized by coordination chain transfer method with Ziegler-Natta and metallocene catalyst as the main catalyst.The structure and thermal properties of the polyethylene wax were characterized.The rheological behavior of the system was studied with the low molecular weight polyethylene and the high density polyethylene.The main contents of the work are as follows:1.A series of molecular weight polyethylenes were synthesized by the coordination chain transfer synthesis method,using the catalyst of magnesium chloride Ziegler-Natta titanium tetrachloride as the main catalyst,triethyl aluminum as the catalyst system.The molecular weight,molecular weight distribution and thermal properties of the products were characterized by GPC,DSC and melt index.The results show that isoprene has an obvious effect on the improvement of polyethylene melting index,and the maximum melting index of polyethylene can reach 46.15g/10 min.The molecular weight of polyethylene was measured by GPC,and the molecular weight and molecular weight distribution of polyethylene decreased after hydrogenation.2.A series of low molecular weight polyethylene wax was synthesized by hydrogenation of dicyclopentadiene two zirconium chloride(/MAO),and the rheological behavior of the blends was characterized by blending with a series of low molecular weight polyethylene wax.The molecular weight,molecular weight distribution,thermal properties,polymer structure and rheology of the polymer were characterized by GPC,DSC,NMR and rheometer.It was found that the energy storage modulus and viscosity of the blends decreased with the increase of the content of polyethylene wax,and the polyethylene wax had a significant influence on the rheological behavior of HDPE,especially in the high frequency region.