Stereocontrolled Phenol‐Yne Click Polymerization Toward High‐Performance Bioplastics with Closed‐Loop Recyclability

Hydroxyl-yne click polymerization is a highly atom-economic and powerful tool for constructing sequence-controlled and structure-diverse unsaturated polymers. However, the cis/trans stereochemistry remains underdeveloped, thus lacking a stereodivergent synthesis of stereocontrolled polymers. Herein, we first report the organocatalyzed stereocontrolled phenol-yne click polymerization of bioderived diphenols and dipropiolates by judiciously changing the substrates, catalysts, and reaction solvents. Various sequence- and stereocontrolled poly(vinyl ether ester)s were effectively synthesized under mild reaction conditions, in which the trans content in the polymeric backbone can be proportionally altered in the range of 46%-100%. More importantly, the bulk properties of these materials such as thermal (T_d,5% of 329-362 °C; T_g of 48-92 °C), mechanical (ultimate tensile strengths of 41-89 MPa, tensile moduli of 960-1991 MPa, and elongations at break of 71%-242%), and transport properties (oxygen transmission rates of 0.2-0.3 bar and water vapor transmission rates of 1.3-2.8 g mm m^-2 day^-1) can be tuned broadly. Moreover, the installed dynamic acetal moieties contribute to the excellent degradability and recyclability of these materials. This study provides an efficient and sustainable strategy for synthesizing stereoregulated biopolymers with closed-loop recyclability, thereby expanding the chemical diversity of click polymers with structure-controlled and tailored properties.