Isocyanate terminated castor oil-based polyurethane prepolymer: Synthesis and characterization

The use of new materials from natural origin in the synthesis of urethane-derived polymers is recently drawing eminent care from social, environmental and also economic viewpoints. In this work, NCO-terminated castor oil-based polyurethane prepolymer (COPUP) is synthesized through the reaction between the isophorone diisocyanate (IPDI) and castor oil (CO) with a variable ratio of the isocyanate (NCO) and hydroxyl (OH) groups (0.5:1; 1:1; 1.5:1; 2:1) analyzed by nuclear magnetic resonance (NMR), Fourier transform infrared (FT-IR) spectroscopy. Furthermore, the polyurethane prepolymers synthesized from IPDI played a significant role of inter-mixing between the soft polyether segments and the hard urethane groups, as shown by the analysis of hydrogen bonding in FT-IR deconvolution. A detailed study of the relationship between structure–property of cured prepolymers was carried out. As a result, COPUP obtained from biomass-derived polyols may enhance a promising alternative to the use of other petrochemicals in the paving industry.