Engineering Ethylene/1-Hexene Copolymers from Ethylene Stock with a Model-Guided Catalyst Feeding Policy

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.

Synthesis and characterization of polyolefin thermoplastic elastomers: A review

“…The model fits well with the polymerization rate, copolymer composition, molecular weight, and distribution obtained from the experiments. Luo et al [ 52 ] further established a model for tandem solution polymerization of ethylene with SNS‐Cr/CGC‐Ti/MAO as a catalytic system. Based on the model, a model‐aided oligomer catalyst feeding strategy was developed to tailor the copolymer composition distribution of ethylene/1‐hexene copolymers.…”

Kinetic Parameter Estimation of the Polyethylene Process by Bayesian Optimization

“…The obtained kinetic parameter lacks the necessary accuracy to predict the consumption of monomers and comonomers. Liu 8 and Luo 9 utilize the method of moments and population balance model to establish the kinetic models of ethylene/octene copolymerization and tandem polymerization of ethylene, respectively. They perform parameter estimation by fitting experimental data and establishing a precise polymerization reaction model for guiding feeding strategy in experimental process aimed at producing specific products.…”