Novel Ti@COF catalysts for the preparation of ultra-high molecular weight linear polyethylene

Abstract

The development of the polyolefin industry hinges on the development of high-performance catalysts. Covalent organic frameworks (COFs), as novel porous materials, hold great potential in heterogeneous catalysis. In this study, Ti@COF catalysts, namely Ti@TbDa and Ti@TtDa, were designed and synthesized under solvothermal conditions and post-modification. Ethylene polymerization experiments demonstrated that Ti@TtDa exhibited an extremely high polymerization activity of 4.31 × 10⁴ g_PE mol_Ti⁻¹ h⁻¹ at a pressure of 0.5 MPa, and the products have opened up new avenues for the production of ultra-high molecular weight linear polyethylene (M_w = 1.57 × 10⁶ g mol⁻¹) and a low molecular weight distribution (D = 4.80). Such catalysts brought new ideas for the design of olefin polymerization catalysts and contributed to the upgrading of the polyethylene industry.