Polyester polyols and polyurethanes from ricinoleic acid

Triols of molecular weights (MWs) 1000-4000, suitable for flexible foams, were prepared by transesterification of methyl esters of ricinoleic acid with trimethylol propane. These polyols were noncrystallizing, relatively low-viscosity liquids. They were reacted with diphenylmethane diisocyanate (MDI) to obtain elastomers having glass transition temperatures below -60 degrees C. Polymer networks from high-MW polyols exhibited relatively high sol fractions suggesting that some cyclization occurred during polyol preparation. The low Shore hardness, relatively low strength and modest elongation of the elastomers were attributed to the specific structure of polyricinoleic chains and the presence of dangling chains, serving as plasticizers. (C) 2008 Wiley Periodicals, Inc.