Utilization of by-product (Shiro-kasu) from wheat starch industry for polyurethane

Polyurethane(PU) foams and films were prepared from Shiro-kasu which was discharged from a commercial wheat starch and gluten production. PU foams were obtained by reacting the mixture of Shiro-kasu and polyol with diphenylmethane diisocyanate. Apparent density of PU foams decreased with increasing Shiro-kasu content because of increase of foaming ratio. The mechanical properties were measured by a tensile test machine. The compression stress of PU foams decreased and the tensile stress of PU films increased with increasing Shiro-kasu content. Thermal properties of PU's were measured by differential scanning calorimetry and thermogravimetry. Glass transition temperature (T-g) of PU's increased and decomposition temperature (T-d) of those decreased with increasing Shiro-kasu content. Biodegradability of PU films was measured by activated sludge method. The weight of PU films in activated sludge remarkably decreased with increasing Shiro-kasu content. These results indicated that Shiro-kasu could be used as a polyol for biodegradable PU.