Copolymerization with cleavable comonomers is a versatile approach to generate vinyl polymer with viable end-of-life option such as biodegradability. Nevertheless, such strategy is ineffective in producing readily degradable 2, 3-dihydrofuran (DHF) copolymer with high-molecular-weight (>200 kDa). The latter is a strong and biorenewable thermoplastic that eluded efficient cationic copolymerization synthesis. Here, we show that an anion-binding catalyst seleno-cyclodiphosph(V)azanes enable the efficient cationic copolymerization with cyclic acetals by reversibly activate both different dormant species to achieve both high living chain-end retention and high-molecular-weight. This method leads to incorporating low density of individual in-chain acetal sequences in PDHF chains with high-molecular-weight (up to 314 kDa), imparting on-demand hydrolytic degradability while without sacrificing the thermomechanical, optical and barrier properties of the native material. This methodology can be readily adapted to traditional cationic polymerization to furnish facile degradable polymers with tunable performances for various applications and environmental sustainability.
