The photocatalytic synthesis and closed-loop recycling of poly(semi-aromatic 1,2-ethanediol)s

Abstract

The strategy of the closed-loop recycling of plastic waste has been recognized as an indispensable approach for solving environmental problems and relieving resource scarcity. However, the design of new monomer-to-polymer-to-monomer recycling systems remains a significant challenge. In this work, starting from dialdehyde monomers, a series of poly(semi-aromatic 1,2-ethanediol)s with good functional-group tolerance has been developed. Catalyzed by a super organophotoreductant, the unprecedented photoreductive pinacol polymerization of dialdehydes afforded various polymeric diols in up to 99% yields with high molecular weights (up to 8.2 kDa). The rigid aromatic-ring backbones raise the decomposition temperature, and different branched structures have different glass transition temperatures. For closed-loop recycling, these polymeric diols could be depolymerized back to the original dialdehyde monomers under oxidation conditions in moderate to high yields. This system offers excellent potential for new sustainable and environmentally friendly polymeric diol materials.