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

• Published in: Journal of applied polymer science 2021-05, Vol.138 (20), p.n/a
• Main Authors: Matsko, Mikhail A., Semikolenova, Nina V., Zakharov, Vladimir A., Soshnikov, Igor E., Shundrina, Inna K., Sun, Wen‐Hua
• Format: Article
• Language: English
• Subjects: Catalysts; Coordination compounds; Ethylene; Materials science; Mechanical properties; Molecular weight distribution; Polyethylene; Polyethylenes; Polymers; polyolefins; Silicon dioxide; structure‐property relationships; thermal properties; Thermodynamic properties
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.50436

Comparative data on the micro‐structures and properties of branched polyethylenes (BPE) produced via ethylene homopolymerization over homogeneous N,N‐α‐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 (Mw[Mn]−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. It was shown a possibility to produce branched polyethylenes (BPE) (17 ‐ 18 CH3(1000C)‐1) via ethylene homopolymerization (without comonomers) over supported catalysts N,N‐α‐diimine LNiBr2/SiO2(Al) with Al(iso‐Bu)3 as a cocatalyst. It is possible to regulate molecular masses (1800‐210 kg mol‐1) and molecular weight distributions (Mw(Mn)‐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.