Isothiocyanate derivatives of soybean oil triglycerides: Synthesis, characterization, and polymerization with polyols and polyamines

Abstract

AbstractIn this article, a novel two step synthesis of soy oil based isothiocyanate is described. Allylicaly brominated soybean oil (ABSO) was reacted first with ammonium thiocyanate in tetrahydro furan to form allylic thiocyanates. These compounds were then converted to isothiocyanated soybean oil (ITSO) by a thermal rearrangement. Conversion was found to be 70%. The structure of the ITSO was characterized by IR and 1 H‐NMR techniques. Then ITSO was reacted with ethylene glycol, glycerol, and castor oil to produce polythiourethanes and ethylene diamine and triethylene tetra amine to produce polythioureas. Thermal properties of the products were determined by DSC and TGA techniques. DSC traces showed Tg's for ethylene glycol polythiourethane at −39 and 58°C, for glycerol polythiourethane at −39 and 126°C, for castor oil polythiourethane at −38°C and −17°C, for ethylene diamine polythiourea at −45°C, and for triethylene tetra amine poly thiourea at −39°C. Additionally, DSC analysis of polythioureas showed an endotherm at around 100°C. All of the polymers started to decompose around 200°C. Tensile properties of the polymers were determined. Polythiourethanes showed higher tensile strength and lower elongation when compared with their urea analogs. Stress at break values of the polymers were 1.2 MPa for glycerol polythiourethane, 0.6 MPa for ethylene glycol polythiourethane, 0.5 MPa for ethylene diamine polythiourea, and 0.9 MPa for triethylene tetra amine polythiourea polymers. Unfortunately, polymers synthesized showed poor solvent resistance. All polymers swelled and disintegrated in CH2Cl2 in 5 h. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010