Ionic liquid-based monolithic porous polymers as efficient flame retardant and thermal insulation materials

It remains very challenging to create porous materials with both good thermal insulation and flame retardancy for construction of energy-saving buildings. Herein, we report the first example of ionic liquid (IL)-based monolithic porous polymers as efficient flame retardant with good thermal insulation, which was synthesized by polymerization of vinyl tetrafluoroborate ionic liquid monomers with polydivinylbenzene (PDVB) as a crosslinker through a facile solvothermal synthesis followed by freeze drying (named as PDVB-BF4ILs). The PDVB-BF4ILs is mainly composed of mesopores with a pore sizes ranging from 8.8 to 20.3 nm. The PDVB-BF4ILs has a decomposition temperature of higher than 320 °C. The PDVB-BF4ILs show high thermal insulation with a low thermal conductivity (0.019W m−1 k−1) in air. Also, the PDVB-BF4ILs possesses excellent flame retardancy with a low peak heat released rate (139.3W g−1). Compared with porous PDVB, the pHRR of PDVB-BF4ILs was reduced by approximately 75%. Torch burn test implies that the PDVB-BF4ILs shows self-extinguishing behavior without generation of any melt dripping, indicating an excellent flame retardancy. Taking advantages of simple fabrication process, easily to be scaled-up, excellent thermal insulation and flame retardancy, such IL-based monolithic porous polymers may have great potential for real applications.