Vinyl polymers with fully degradable carbon backbones enabled by aromatization-driven C–C bond cleavage

Abstract

Degradation of carbon-backbone polymers, which make up most plastics, remains a formidable challenge owing to strong and inert main-chain C–C bonds. While incorporation of comonomers that generate backbone radicals under certain conditions can induce degradation of the polymer chain, such strategies yield complex oligomer mixtures. Here we report aromatization-driven C–C bond cleavage as a viable and powerful strategy to endow the degradability into carbon backbones using acrylic polymers as a model example. The key to this new strategy is the efficient, living, alternating addition copolymerization of acrylates with simple, commercially available and biorenewable coumarin using a frustrated Lewis pair cooperative catalyst. The resulting acrylic copolymers are strong, transparent thermoplastics with key thermal, optical, mechanical properties comparable or superior to poly(methyl methacrylate). Under strong base, alternating copolymers can completely degrade at room temperature through efficient cleavage of main-chain C–C bonds utilizing aromatization as a thermodynamic driving force, to generate pure, pharmaceutically valuable molecules, thus affording durable, robust yet fully degradable carbon-backbone acrylic polymers.