Hollow glass microspheres-based ultralight non-combustible thermal insulation foam with point-to-point binding structure using solvent evaporation method

Abstract Usually, the thermal insulation and flame retardancy of traditional building material are mutually exclusive. It is very challenging to make a material with both of these properties. In this study, a hollow glass microsphere based ultralight non-combustible thermal insulation foam (HGMs-TIF) with point-to-point binding structure was prepared using solvent evaporation method. Five samples were prepared with different mass ratios of hollow glass microspheres and phenolic resin. The results showed that as the mass proportion of HGMs increase from 60.6% to 88.5%, the thermal insulation as well as flame retardancy of composite is improved. Remarkably, the HGMs-TIF-01 which has the largest proportion of HGMs (88.5%) shows lowest thermal conductivity of 0.0452 W/(m∙K) and lowest gross heat of combustion of 2.844 MJ/kg, what implies it is a non-combustible material according to the National Standard of the People's Republic of China GB/T 8624-2019 (i.e. gross heat of combustion of the standard of class A2 is lower than 3 MJ/kg). Besides, the HGMs-TIF-01 also is a lightweight and high-strength material, which has a low density of 0.142 g/cm3 and a high compressive strength of 0.748 MPa. It is helpful for the further design of the non-combustible thermal insulation material.