Polyurethanes based on renewable polyols from bioderived lactones

Ring opening transesterification polymerization of lactones derived from menthone and carvomenthone was used to synthesize polyols for polyurethane film formulations. The polyols were synthesized at 140°C using tin(ii) octoate as catalyst, diethanolamine as trifunctional initiator, and with ratios of lactone:initiator of 9:1 or 18:1. Polyol structural features were deduced by comparison of NMR spectral data with those of simple model amide/esters of the initiator. Films were formulated from the renewable polyols, diphenylmethane diisocyanate [or poly(diphenylmethane diisocyanate)], and diethylene glycol. Thermal and mechanical properties of these polyurethane films were measured, demonstrating their potential utility as biobased thermosets for rigid or flexible foams.