Effects of talc/hollow glass beads on the flame retardancy of silicone foams

Abstract

Low-density, flame-retardant silicone foams (SiFs) were obtained through appropriately blending super fine talc powder (SFT) and hollow glass beads (HGB). The effects of SFT and HGB on mechanical properties, flame retardancy, and thermal stability of SiFs were investigated. The incorporation of SFT significantly improved the mechanical properties of SiFs, and HGB showed a positive effect on reducing the density of the SiFs. The flame retardancy of SiFs could be prominently improved by interfusing SFT and HGB. SiFs could achieve the UL-94-V0 rating with no less than 10 wt% SFT or 5 wt% HGB. Remarkably, the peak heat release rate and total heat release were the lowest when 30 wt% SFT and 1 wt% HGB were incorporated. Thermogravimetric analysis (TG) test showed that SFT and HGB could prompt the char formation in the degradation process of SiFs. The initial decomposition temperature and the residue at 900 °C of SiF with 30 wt% SFT and 1 wt% HGB were noticeably higher than that of pure SiF. It was a promising strategy for preparing flame retardant SiFs with improved mechanical performance and thermal stability by incorporating SFT and HGB.