Thermal and Mechanical Properties of Sodium Lignosulfonate-based Rigid Polyurethane Foams Prepared with Three Kinds of Polyols

Abstract

Rigid polyurethane (PU) foams were prepared by the following procedures. Sodium lignosulfonate (LS) was dissolved in diethylene glycol (DEG), triethylene glycol (TEG) or polyethylene glycol (average molecular weight, Mn200: PEG200). Rigid polyurethane foams were prepared by reacting the obtained solutions with polyphenyl polymethylene polydiisocyanate (MDI) in the presence of a silicone surfactant, di-n-butyltin dilaurate (DBTDL) and water. Thermal and mechanical properties of these polyurethanes (PU’s) were studied by differential scanning calorimetry (DSC), thermogravimetry (TG) and mechanical tests. Glass transition temperatures (Tg’s) of PU’s increased with increasing LS content and decreased with increasing Mn of ethylene glycol. Thermal degradation took place in two stages and temperatures (Td‘s) decreased with increasing LS content. Compressive stress at 10% strain (σ10) and compressive yielding stress (σy) increased with increasing apparent density (ρ) of PU’s.