Synthesis and Characterization of Non-Isocyanate Polyurethane from Epoxidized Linoleic Acid - A Preliminary Study

Non-isocyanate polyurethane (NIPU) was synthesized from epoxidized linoleic acid (ELA) from rubber seed oil. In this study, carboxylation method was used to synthesize a new monomer, carboxylated linoleic acid (CLA) to produce urethane inter-linkage polymer. ELA with tetrabutylammonium bromide (TBABr) as catalyst was purged with carbon dioxide as gas reactant. Pressure and temperature reactions were controlled at 10 psi and 150 degrees C. CLA was mixed with ethylenediamine (EDA) and the viscous mixture was cured in a covered mold in an oven at 100 degrees C and curing was performed after 12 hours. Tacky test was done to evaluate the curing. The initial epoxy value of ELA was 7.36 % and it was observed during synthesis to reduce via Oxygen Oxirane Content test, which illustrated the conversion of ELA to CLA. The formation of epoxy group in ELA to carboxylate functional group in CLA was characterized using Fourier Transform Infrared (FTIR) at absorption peak of 1803.69 cm(-1) that represent cyclic carbonate group. H-NMR was used to support the characterization of ELA and CLA.