Bioinspired Sustainable Polymer with Stereochemistry-Controllable Thermomechanical Properties

The regulation of polymer properties based on stereochemistry is essential but rarely studied. Inspired by the isomerization of unsaturated phospholipids in cell membranes, we report a novel method of preparing stereocontrolled polymer using sustainable Eucommia ulmoides gum (EUG) as a raw material. Under the catalysis of thiyl radical, EUG with 100% trans-1,4-polyisoprene structure isomerized to cis-configuration partly in a controllable way, thus achieving the rational modulate of thermomechanical properties. The isomerization mechanism was verified by density functional theoretical calculation. The isomerized EUG (IEUG) with low cis content (≤8.7%) can serve as plastics or shape memory materials, while high cis content (≥10.7%) IEUG transferred into elastomer materials. Especially for IEUG-10.7%, its vulcanizates without filler reinforcement shows high tensile strength (15.5 MPa) and elasticity (97%) comparable to natural rubber due to its strain-induced crystallization ability, which has the potential to be the second natural rubber. This paper provides a new strategy for stereocontrol of polymer properties, and the prepared materials have broad application prospects in the intelligent sensing and rubber industry.