Formulation and characterization of a polyurethane-based flame-retarding polymer derived from soybean seed oil

Abstract

A polyurethane-based polymer derived from soybean seed oil was formulated using boric acid and talc as flame retardants, hot water floatation method was employed for the extraction of the soybean oil. Epoxidation and hydroxylation methods were carried out on the extracted seed oil to produce the polyol. The acid value, viscosity and iodine values of the crude soybean, epoxidized soybean oil and the soybean polyol detected was 15.27±0.90 mg KOH/g, 1.55±0.0097 Pa, 119.00 g I₂ /100g; 10.79±0.50 mg KOH/g, 0.721±0.0068 Pa, 78.32 g I₂ /100g and 13.44±0.65 mg KOH/g, 1.183±0.0092 Pa and 65.43 g I₂ /100g respectively. The effect of the reaction times on iodine value conversion and oxirane oxygen content of the epoxidized soybean seed oil was studied for the polyurethane formulation which showed appreciable rate of conversion. The effects of flame retardants on the flame propagation rate, ignition time, after-glow time, flame duration and char formation of the polyurethane foam were studied, it was observed that the polyurethane foam showed good resistance to flame propagation as the concentration of the flame retardants increased, reduced after-glow and flame duration times were also observed as the concentration of the flame retardants were increased. Thus, boric acid-talc nanocomposites was effective. However, the ignition time and % char formation showed increase as the concentration of the flame retardants were increased which was expected due to its suitability.