Biobased Polyurethanes from Rapeseed Oil Polyols: Structure, Mechanical and Thermal Properties

Biobased polyols were synthesized from rapeseed oil (RO) with diethanolamine (DEA), triethanolamine (TEA) and glycerol (GL) at different molar ratios. The structures of the synthesized polyols were analyzed using FTIR-ATR spectroscopy. Polyurethane (PU) networks from RO/DEA polyols and polymeric MDI showed higher tensile strength, modulus and hardness, but their elongation at break decreased, compared to the case of the PU obtained from RO/TEA and RO/GL polyols. The tensile strength and modulus of PU networks increased with increasing PU cohesion energy density (CED) and decreasing molecular weight between crosslinks Mc. From the thermogravimetric analysis and its derivative thermograms, at the first stage of destruction (below 5 % weight loss) in the air and inert atmosphere, the PU obtained from RO polyols were ranked in the following order: PU RO/GL > PU RO/TEA > PU RO/DEA, and their thermostability was higher than that of the PU based on propylene oxide.