Ethanol organosolv lignin-based rigid polyurethane foam reinforced with cellulose nanowhiskers

An ethanol organosolv lignin polyol, prepared by reacting lignin with propylene oxide catalyzed by potassium hydroxide, was used to synthesize rigid polyurethane foam which was further reinforced by cellulose nanowhiskers (CNWs) up to 5 wt%. The resulting nanocomposites have shown significantly improved mechanical and thermal properties primarily attributed to the phenolic structure and high functionality of lignin as well as the rigidity of CNWs and crosslinking introduced by CNWs.