Durable flame-retardant, smoke-suppressant, and thermal-insulating biomass polyurethane foam enabled by a green bio-based system

Bio-based polyurethane foam has attracted increasing attentions due to eco-friendliness and fossil feedstock issues. However, the inherent flammability limits its application in different fields. Herein, we demonstrate a green bio-based flame-retardant system to fabricate polyurethane foam composite with durable flame retardancy, smoke suppression, and thermal insulation property. In this system, the green bio-based polyol (VED) with good reactivity and compatibility plays a role of flame retardant and EG acts as a synergistic filler. As a result, the LOI value of foam composite increased to 30.5 vol.% and it achieved a V-0 rating in the UL-94 vertical burning test. Additionally, the peak heat release rate (pHRR) and the total smoke production (TSP) decreased by 66.1% and 63.4%, respectively. Furthermore, the foam composite maintained durable flame retardancy after accelerated thermal aging test, whose thermal-insulating property was maintained even after being treated in high-humidity environment with 85% R.H. for a week. This work provides a facile strategy for durable flame retardancy and long-term thermal insulation performance, and creates opportunities for the practical applications of bio-based foam composites.