Vegetable oil-based triols from hydroformylated fatty acids and polyurethane elastomers

Abstract

Novel bio-based polyols were prepared from hydroformylated oleic acid (9/10-hydroxymethyl-octadecanoic acid) methyl esters (HFME) and trimethylolpropane by transesterification. Hydroformylation produces primary hydroxyls, which allow relatively lower transesterification temperatures and better yields than hydroxy fatty acids with secondary hydroxyl groups. These non-crystallizing polyols have no double bonds and their viscosities are acceptable. Polyurethane (PU) elastomers prepared by reaction of these polyols with diphenylmethane diisocyanate had glass transition temperatures from –33 to –56 °C, depending on the molecular weight of the triols. Tensile strength and Shore A hardness were higher, and elongation, swelling and sol fraction lower than those of corresponding networks from polyricinoleic acid polyols. The plasticizing effect of longer dangling chains in HFME-based PU compensated, to a degree, the presence of double bonds in ricinoleic acid, effectively resulting in similar glass transitions between the two families of polyols.