Improved mechanical property, thermal performance, flame retardancy and fire behavior of lignin-based rigid polyurethane foam nanocomposite

Liquefied lignin-based polyol (LBP) was successfully obtained by liquefying calcium lignosulphonate with a polyhydroxy alcohol mixture, which can substitute 30 % petroleum-based polyether polyol to prepare rigid polyurethane foam (RPUF). In an effort to reduce the flammability and smoke release from RPUF, liquefied LBP in combination with commercial flame retardant polyol (FRP), polyurethane microencapsulated ammonium polyphosphate (MAPP) and organically modified layered double hydroxide (OLDH) were used to fabricate halogen-free flame retardant RPUF nanocomposite. The influences of incorporating LBP, FRP, MAPP and OLDH into RPUF on the thermal conductivity, mechanical property, thermal performance, flame retardancy and fire behaviors of RPUFs were comprehensively investigated. It is noteworthy that simultaneously incorporating LBP, FRP, MAPP and OLDH into RPUF can significantly improve the mechanical property, thermal performance, flame retardancy and fire behavior of RPUF. The improved flame retardancy and fire behavior of RPUF are attributable to combined effects among LBP, FRP, MAPP and OLDH in gas phase and condensed phase.