Synthesis of Polyethylenes with In-Chain Isolated Carbonyls from CO2 and Ethylene

Abstract

Aiming at accessing polyethylenes bearing in-chain degradable functionality, copolymerization of carbon dioxide (CO2) with ethylene has long been recognized as a significant but highly challenging transformation. Nevertheless, most trials resulted in ethylene homopolymerization because of the endothermic property and high energy barriers of CO2 insertion during polymer chain propagation. Here we report an unprecedented protocol synthesis of polyethylenes with low content carbonyls from CO2 and ethylene by the combination of photocatalytic CO2 reduction and palladium catalyzed coordination/insertion polymerization. The introduction of photocatalytic systems provides an easy way to tune the carbonyl content and insertion selectivity of the polyethylene copolymers. Significantly, excellent selectivity (up to >99%) for incorporating isolated carbonyls in the main polymer chain has been achieved, which allows the copolymers to retain the properties of polyethylene but makes them photodegradable.