Eco-friendly and efficient flame retardant rigid polyurethane foam reinforced with lignin and silica aerogel.

With the continuous improvement of living standards, the development of eco-friendly rigid polyurethane foam (RPUF) materials with excellent flame retardancy, thermal insulation, and outstanding mechanical strength has become an urgent challenge. This study presented an innovative strategy using lignin as a mechanical reinforcement and flame-retardant synergist, combined with DMMP and EG as highly efficient flame retardants. Furthermore, the incorporation of a silica aerogel coating via surface post-treatment significantly enhanced the flame retardancy of the composite.