(643d) Engineering Polyolefin Thermoplastic Elastomers with Model-Guided Catalyst Feeding Policies Using a Tandem Polymerization

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 an approach of model-guided oligomerization catalyst feeding for tailoring copolymer composition distribution, producing ethylene/1-hexene copolymers with high performance. The copolymers having a cumulative copolymer composition of 6.1 mol% and instantaneous composition distribution in the range of 0-8.0 mol% can be tailored using this strategy, compared with a narrower distribution of 3.9-6.6 mol% under one-time feeding of oligomerization catalyst. The model-guided feeding strategy further permitted the synthesis of 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, and broader distribution of lamellar thickness increased to 1.33 from 1.16. As a result, the tensile strength of the copolymer increases to 38.1 MPa from 26.3 MPa and the elongation at break to 740 % from 685 %. Tandem polymerization of ethylene with model-guided feeding of oligomerization catalyst has a great potential to engineer high-performance polyolefin thermoplastic elastomers.