Hollow glass microspheres modified polyurethane sponge with enhanced flame retardancy

Abstract Nowadays, with the continuous improvement of domestic fire safety requirements, the development of materials with better thermal insulation and flame retardant performance is of great significance to modern building energy conservation. Herein, hollow glass microspheres (HGM) modified polyurethane sponge (PU‐HGM) with enhanced flame retardancy is prepared by dipping HGM onto PU sponge through polydimethylsiloxane. The PU‐HGM sponge exhibits porous network structure with rich micron sized pores, as well as the HGM with closed hollow spherical structure endow the prepared PU‐HGM better thermal insulation performance, and the thermal conductivity is 0.050 W m −1 K −1 . Besides, the PU‐HGM maintains excellent elasticity of PU sponge, and shows strong mechanical strength, the stress of PU‐HGM sponge was as high as 882 kPa at 70% strain after 3 cycles. More importantly, compared with pure PU sponge, the PU‐HGM shows excellent flame retardancy. It keeps its original shape after combustion, and no obvious flame was observed on the surface of PU‐HGM sponge. Thus, combined with its high mechanical strength, low material cost, simple and scalable preparation method, the as‐prepared PU‐HGM sponge shows great potential for application in the field of heat insulation and flame retardant.