Fabrication of Fire-Retardant and Impact-Resistant Hierarchical Rigid Porous Composites via Surface Coating Strategy

Rigid polyurethane foam (RPUF) shows great application potential in the fields of architecture, household, and transportation due to its lightweight, durability, and excellent heat insulation. However, it remains challenging to construct flame-retardant and impact-resistant RPUF composites with good thermal insulation through a facile approach. Herein, multifunctional hierarchical RPUF composites were prepared by simple one-pot foaming and brush-coating methods. Due to the hierarchical structure and multifunctional polyborosiloxane/phytic acid/polyethylenimine (PBS/PAP) coating, the as-created foams displayed excellent fire safety and impact resistance. For instance, the peak of heat release rate and total heat release of the RPUF composite with the PBS/PAP coating decreased by 70.1 and 57.0%, respectively, relative to those of pure RPUF. Furthermore, the composite showed good heat insulation and improved thermal stability performance. This work offers a paradigm for the design of multifunctional RPUF composites with outstanding fire resistance, impact resistance, and heat insulation properties, which represent prospective potential in safety protective materials.