Bio-based polyurethane composite foams with inorganic fillers studied by thermogravimetry

Bio-based polyurethane (PU) composite foams filled with various inorganic fillers, such as barium sulfate (BaSO4), calcium carbonate (CaCO3) and talc were prepared using polyols, such as diethylene glycol, triethylene glycol and polyethylene glycol (molecular weight ca. 200) containing molasses and lignin. Reactive hydroxyl groups in plant components and above polyols were used as reaction sites. Morphological observation of fracture surface of composites was carried out by scanning electron microscopy. Thermal properties of bio-based PU composites were examined by thermogravimetry. It was found that the above composites decompose in two stages reflecting decomposition of organic components. Decomposition temperature increased with increasing filler content, when plant components were homogenously mixed with inorganic fillers. Activation energy calculated by Ozawa-Wall-Flynn method was ca. 150 kJ mol−1. The durability of composites was predicted using kinetic data. Calculated values indicate that composites with fillers are more durable than that of those without fillers at a moderate temperature region.