Thermal properties of lignin- and molasses-based polyurethane foams

Lignin- and molasses-based polyurethane (PU) foams with various lignin/molasses mixing ratios were prepared. The hydroxyl group in molasses and lignin is used as the reaction site and PU foams with various isocyanate (NCO)/the hydroxyl group (OH) ratios were obtained. Thermal properties of PU foams were investigated by differential scanning calorimetry (DSC), thermogravimetry (TG) and thermal conductivity measurement. Glass transition temperature (T-g) was observed depending on NCO/OH ratio in a temperature range from ca. 80 to 120 degrees C and thermal decomposition temperature (T-d) from ca. 280 to 295 degrees C. Mixing ratio of molasses and lignin polyol scarcely affected the Tg and Td. Thermal conductivity of PU foams was in a range from 0.030 to 0.040 W m(-1) K-1 depending on mixing ratio of lignin and molasses.