Engineering Ethylene/1-Hexene Copolymers from Ethylene Stock with a Model-Guided Catalyst Feeding Policy
Liqiong Luo, Kan Liu, Jie Jiang, Mengfei Qi, Qiulin Li, Pingwei Liu, Bo‐Geng Li, Wenjun Wang
Abstract
The synthesis of ethylene/α-olefin copolymers with controlled chain composition distribution via tandem polymerization of ethylene is of great challenge because of the complexity of the reaction process involving both ethylene oligomerization and copolymerization. Herein, we report a model-guided oligomerization catalyst feeding approach for tailoring copolymer composition distribution, producing ethylene/1-hexene copolymers with high performance. The copolymers having a cumulative copolymer composition of 5.7 mol % and instantaneous composition distribution in the range of 0–7.3 mol % can be tailored using this strategy, compared to a narrower distribution of 2.8–7.6 mol % under one-time feeding of the oligomerization catalyst. Meanwhile, the model-guided feeding strategy afforded the copolymers having higher contents of [EEE] and [EHH] sequences at 85.93 and 0.33% in comparison with 83.44 and 0.03% for one-time feeding. The lamellar thickness distribution is also increased from 1.16 to 1.33. As a result, the tensile strength of the copolymer increases from 26.3 to 38.1 MPa and the elongation at break increases from 685 to 740%. Tandem polymerization of ethylene with the model-guided feeding of the oligomerization catalyst promises the preparation of high-performance copolymers of ethylene and 1-hexene or other α-olefins.