IMX Seminar Series - Development of High Performance Polyolefin Elastomers

Polyolefins accounting for more than 50% of overall plastic consumption, is the largest chemical product in the world. Polyolefin elastomer (POE), a random copolymer of ethylene and α-olefin, is one of the high-end polyolefins possessing both rubbery elasticity and plastic processability. By designing and tailoring the chain structures that provide elasticity and plasticity, POEs with better mechanical properties and performances can be synthesized while maintaining the same copolymer composition. We thus design a comb branched polyolefin elastomer (CPOE) using high-temperature solution tandem polymerization. The CPOE has a crystalline polyethylene (plasticity, hard segment) as the side chain and the amorphous ethylene/α-olefin copolymer (elasticity, soft segment) as the backbone.1 Both soft and hard segments of the CPOE can be adjusted, thus increasing the melting point and reducing the glass-transition temperature. The rheological properties of the CPOE reveal the influence of long side chains on the elastic-plastic transition, chain conformation, and melt viscosity. By incorporating diene olefins in polymer chains, a reversible dynamic cross-linking is introduced to offer a synchronous enhancement in mechanical properties and processability of the POE.2 Furthermore, tandem polymerization kinetics models for the POE and CPOE are developed. Under the model’s guidance in controlling the addition of oligomerization catalyst, the copolymer composition distribution in the POEs is tailored to improve both strength and toughness of the polymers.3 The polymer chain structure design and polymerization process control thus provide an effective way for the development of high-performance polymers.
References:
1. K Zhang, P Liu, W-J Wang, B-G Li, W Liu, and S Zhu, Preparation of Comb-Shaped Polyolefin Elastomers Having Ethylene/1-Octene Copolymer Backbone and Long Chain Polyethylene Branches via a Tandem Metallocene Catalyst System, Macromolecules 2018, 51, 8790−8799
2. Y Xiao, P Liu, W-J Wang, B-G Li, Dynamically Cross-Linked Polyolefin Elastomers with Highly Improved Mechanical and Thermal Performance, Macromolecules 2021, 54, 10381−10387
3. L Luo, K Liu, J Jiang, M Qi, Q Li, P Liu, B-G Li, W-J Wang, Engineering Ethylene/1-Hexene Copolymers from Ethylene Stock with a Model-Guided Catalyst Feeding Policy, Macromolecules 2022, 55, 462−471
Bio: Dr. Wen-Jun Wang is currently a professor of Chemical Engineering at Zhejiang University (ZJU) and an adjunct professor of McMaster University (Mac). He received a chemical engineering bachelor degree at ZJU in 1986. After receiving his PhD degree in the field of polymer reaction engineering (PRE) at ZJU in 1995, he undertook his post-doctoral research in PRE at Mac. Then he spent his career in R&D and management positions with Coveright Surfaces Canada and Nexwood Industries Ltd, Canada, for several years before he joined the Department of Chemical and Biological Engineering of ZJU as a faculty member in 2008. His research lies in high-performance polyolefins, biodegradable polymers/composites, polymer nanocomposites, and reuse/recycling of post-consumer polyolefins. He has authored over 140 papers and has more than 40 granted patents.