Bio-base polyurethane building material derived from lignin

The synthesis of bio-base polymer materials from renewable wood biomass resources has attracted lots of attention. Polyurethane building materials based on lignin were prepared by lignin polyol and isocyanate. Lignin was modified by polyethylene glycol and glycerol to obtain lignin polyol, and polyurethane material based on lignin was prepared from lignin polyol and isocyanate. Gel time for polymerization, morphology, compressive strength, thermal conductivity and burning behavior of lignin based polyurethane were investigated. The results showed that the apparent activation energy for the polymerization of lignin based polyurethane was low. Compressive strength changed with lignin polyol content, and reached peak value with 30% lignin polyol content. When lignin polyol content was 30%, the thermal conductivity was 0.02517 W/m·K. The heat release rate curves presented an initial peak followed by a drop and then the heat release processed in a gentle manner, reflecting the formation of flame retardant char as a barrier. It was detected that lignin could be used to prepare polyurethane in replacement of petroleum polyols. This study will pave the way for the application of lignin in bio-base polyurethane heat insulating building material.