Sulfonated porous organic polymer supported Ziegler–Natta catalysts for the synthesis of ultra-high molecular weight polyethylene

Abstract

Porous organic polymers (POPs) are attracting attention for their easy functionalization and potential as catalyst supports in olefin polymerization. In this study, sulfonated POP (s-POP) supported Ziegler–Natta catalysts were used for ethylene polymerization, producing ultra-high molecular weight polyethylene, with M_ν reaching up to 6.83 × 10⁶ g mol⁻¹. The maximum M_ν of polyethylene was achieved by Cat-3 with DIBP as the internal donor, albeit with a partial loss of catalytic activity. Polymerization conditions also play a pivotal role in determining the molecular weight of polyethylene. Hydrogen, being the most efficient chain transfer agent, can decrease the molecular weight to 9.68 × 10⁴ g mol⁻¹ at higher hydrogen concentrations ([H₂] : [C₂H₄] = 0.83), and the s-POP-supported ethylene polymerization catalysts were observed to exhibit high sensitivity to hydrogen response. The effects of polymerization temperature, [Al] : [Ti] molar ratio, and ethylene pressure on ethylene polymerization were thoroughly investigated.