Precise Synthesis of Ultra-High-Molecular-Weight Polymers Bearing Pendant Vinyl Groups by Living Lewis Pair Polymerization

Polymers bearing pendant vinyl groups are important building blocks for functional materials, yet their synthesis remains challenging, especially in the ultrahigh-molecular-weight (UHMW) regime. Herein, we report a frustrated Lewis pair (FLP) polymerization system comprising (1-(diethylphosphaneyl)ethylidene)triphenyl-λ 5 -phosphane and diisobutyl (2,6-di tert -butyl-4-methylphenoxy) aluminum ( Ph Y Me PEt 2 /(BHT)Al i Bu 2 ) that enables chemoselective, living polymerization of polar divinyl monomers. This approach affords soluble poly(allyl methacrylate) (PAMA) with UHMW ( M n up to 1932 kg/mol) and narrow dispersity ( D̵ as low as 1.06). The living characters are of this polymerization system were supported by successful chain-extension experiments, linear growth of the number-average molecular weight ( M n ) with conversion and with the monomer-to-initiator ratio, and the synthesis of well-defined di- and triblock copolymers via sequential comonomer addition. More importantly, UHMW PAMA exhibited enhanced thermal stability and toughness relative to its conventional-molecular-weight counterpart. In particular, PAMA with an M n of 1932 kg/mol showed a 3.1-fold increase in toughness compared to PAMA with an M n of 62 kg/mol. Similarly, the UHMW copolymer of AMA and 2-ethoxyethyl methacrylate (EEMA) also exhibited improved toughness. These findings establish a new platform for the development of high-performance functional materials.