Rigid Polyurethanes, Polyesters, and Polycarbonates from Renewable Ketal Monomers

Abstract

Two novel biobased diols containing rigid cyclic ketal functionalities have been synthesized on a relatively large scale from glycerol and two diketones, i.e., 1,4-cyclohexanedione and 4,4′-bicyclohexanone. The diols have been used in several types of step growth reactions, resulting in polycarbonates, polyesters, and polyurethanes. While molecular weights (Mn) of up to 50 kg mol–1 are obtained for the polyurethanes, they also exhibit high glass transition (Tg = 95–150 °C) and degradation temperatures (Td = 260–320 °C), are transparent, and show a high mechanical strength (E = 1.10–1.35 GPa) but brittle behavior. For the polycarbonates, Mn values higher than 24 kg mol–1 and Tg’s in the range of 70–100 °C have been obtained. Moreover, the polycarbonates show good mechanical properties like ductility and are transparent. Finally, a new generation of fully renewable polyesters have been synthesized with dimethyl succinate and dimethyl furan dicarboxylate. While moderate molecular weight values are obtained, the polyesters show Tg’s of up to 96 °C as well as high Td’s (±315 °C).