Effect of Lignin Polyol Incorporation on the Properties and Flame Retardancy of Polyurethane Foam

This study investigates the potential of lignin as a partial polyol replacement in polyurethane (PU) foam production and evaluates the impact of varying lignin content on the foam's physical and chemical properties.Lignin-based polyurethane (LPU) foam were successfully fabricated with different lignin contents, and FT-IR, XPS, and EA analyses confirmed the formation of urethane bonds between lignin and PU.As lignin content increased, the reactivity of the PU network changed, significantly impacting the foam's properties.Contact angle measurements revealed that the higher the lignin content, the more hydrophobic the foam, indicating lignin's role in enhancing the foam's water resistance.Additionally, compressive strength improved as lignin content increased, suggesting lignin's reinforcing effect within the PU matrix.The foam's thermal stability and flame resistance were also positively affected, with higher lignin content enhancing flameretardant performance.These results demonstrate that lignin is a promising sustainable polyol alternative, offering improved mechanical, thermal, and flame-retardant properties for PU foams.Furthermore, this study suggests that LPU foams with tunable properties can be applied in a wide range of fields, contributing to the development of more eco-friendly and functional materials.