Formation of branched polyethylenes by ethylene homopolymerization using LNiBr₂ homo- and heterogeneous precatalysts: Interpretation of the polymer structures in comparison with commercial LLDPE

Comparative data on the micro-structures and properties of branched polyethylenes (BPE) produced via ethylene homopolymerization over homogeneous N,N-alpha-diimine LNiBr2 complexes with different ligand composition (AlEt2Cl as a cocatalyst) and corresponding supported catalysts LNiBr2/SiO2(Al) (Al[iso-Bu](3) as a cocatalyst) are presented. Noticeable differences were observed between micro-structures of BPEs obtained using homo- and heterogeneous LNiBr2 complexes as catalysts. Supported catalysts produce BPEs with the majority of methyl branches (17-18 CH3(1000 C)(-1) characterized by different molecular masses (1800-210 kg mol(-1)) and molecular weight distributions (M-w[M-n](-)(1) = 5.9 and 2.6). Thermal and mechanical properties of these BPE samples obtained over supported Ni catalysts are similar to those of commercial LLDPE samples prepared with metallocene and Ziegler-Natta catalysts.