Thermally stable <i>C</i><sub>2</sub>-symmetric α-diimine nickel precatalysts for ethylene polymerization: semicrystalline to amorphous PE with high tensile and elastic properties
Xiaoxu Li, Zexu Hu, Qaiser Mahmood, Yizhou Wang, Sunny Sohail, Song Zou, Tongling Liang, Wen‐Hua Sun
Abstract
-substituents hindered the rate of monomer insertion, chain propagation, and chain walking reactions, leading to the synthesis of semi-crystalline polyethylene with an exceptionally high melt temperature of 134.6 °C and a high crystallinity of up to 31.9%. Most importantly, nickel bromide complexes demonstrated significantly higher activity compared to their chloride counterparts, while the latter yielded polymers with higher molecular weights and increased melt temperatures. These high molecular weights, coupled with controlled branching degrees, resulted in polyethylenes with excellent tensile strength (up to 13.9 MPa) and excellent elastic properties (up to 81%), making them suitable for a broad range of applications.