Comonomer-controlled synthesis of long-chain branched (LCB)-polyethylene

In this contribution, we disclose the ability of α,ω-diene comonomers, namely 1,7-octadiene and 1–10-undecadiene, as long-chain branching (LCB)/cross-linking promoters in ethylene polymerization catalyzed by bis(indenyl) bis(cyclopentadienyl) catalyst systems, rac-{EBTHI}ZrCl2 (Zr-1) (nBuCp)2ZrCl2 (Zr-2). Both under homogeneous heterogeneous (slurry) conditions, Zr-1-based systems efficiently produced LCB/cross-linked polymers even with very small amounts diene, demonstrated melt rheology measurements. On other hand, higher co-monomer concentrations were required for Zr-2/MAO system, while only linear PEs isolated presence its silica-supported version supp-Zr-2 operated regardless amount diene employed. Rheological NMR spectroscopy studies proved that consumption formation structures take place during early stages polymerization. The experimental observations rationalized DFT computations.