Polyols and polyurethanes from hydroformylation of soybean oil

This paper compares physical and mechanical properties of polyurethanes derived via the hydroformylation approach and is a part of our study on the structure-property relationships in polyurethanes created from vegetable oils. The double bonds of soybean oil are first converted to aldehydes through hydroformylation using either rhodium or cobalt as the catalyst. The aldehydes are hydrogenated by Raney nickel to alcohols, forming a triglyceride polyol. The latter is reacted with polymeric MDI to yield the polyurethane. Depending on the degree of conversion, the materials can behave as hard rubbers or rigid plastics. The rhodium-catalyzed reaction afforded a polyol with a 95% conversion, giving rise to a rigid polyurethane, while the cobalt-catalyzed reaction gives a polyol with a 67% conversion, leading to a hard rubber having lower mechanical strengths. Addition of glycerine as a cross-linker systematically improves the properties of the polyurethanes. The polyols are characterized by DSC. The measured properties of polyurethanes include glass transition temperatures, tensile strengths, flexural moduli, and impact strengths.