Synthesis of Branched Polyethylene by Catalytic Degradation-Isomerization of High-Density Polyethylene in the Presence of Silica-Alumina Catalyst

Abstract

Branched polymers were synthesized through the process of molecular-weight-decrease reaction in the presence of silica-alumina catalyst. Gaseous products, liquid products, branched oligomers (Mw=400) and branched polymers (M_η=1.1x10₄-2.8x10₄) were obtained by the reaction. The straight-c1iain branches (C₁-0₅, C₆ and/or higher) and branched branches (2-ethylhexyl, 2-ethylpemtyl and 2-ethylbutyl) were found in the branched polymer by means of ¹³C-NMR measurements. The highest concentration of total branches in the polymer was 71 branches/1000 CH₂ and the yield of the polymer was 20 wt%. This concentration is much higher than that in commercial polyethylenes containing 10-20branches/1000 CH₂. Similar branches were, also found in the branched oligomer.