Novel Bio-based Thermoplastic Polyurethanes Derived From Oleanolic Acid

A series of novel polyurethanes (PU) were synthesized by incorporation of erythrodiol (ErDO), produced by direct reduction of the naturally occurring pentacyclic triterpenoid oleanolic acid (OA). Polyaddition was performed with four different diisocyanates, including the bio-based 1,5-pentamethylene diisocyanate (PDI). PUs were obtained with Mn values up to 43 kg mol–1 (from size-exclusion chromatography), thermal stability up to 310 °C, and high glass-transition temperatures (Tg) up to approximately 250 °C. Copolymerization with 1,6-hexanediol produced a series of fully biobased, ternary ErDO/PDI-containing PUs with Tg ranging from 206 to 81 °C, without compromising thermal stability.