Preparation And Properties Research On The Ceramic Silicone Rubber

Silicone rubber can be an excellent fire retardant material because of its desirable properties on fire, such as nonflammable, low heat release rate, slow burning rate without both the flaming drip and the toxic smoke. However, the product produced by firing silicone rubber is powder without any strength and could hardly continue to retard firing, which limits its application. Therefore, ceramic silicone rubber was prepared by adding ceramic filler into silicone rubber in this paper, the material had excellent properties similar to the silicone rubber at room temperature and tranformed into hard ceramic shell after ablation at high temperature. The shell could continue to resist both the ablation of flame and the impact of external forces, which made it to play the role of isolating the falme and preventing the fire.The effect of type, content and compound of ceramic filler on properties of ceramic silicone rubber before and after abalation were investigated. The results showed that wollastonite and mica could improve flame retardant property, thermal stability and mechanical properties after ablation at high temperature of silicone rubber, while reducing the mechanical properties at room temperature. The silicone rubber added with acicular wollastonite had preferable thermal stability and the acicular wollastonite had optimum draw ratio, when the content of acicular wollastonite was 60%, the temperature of highest degradation rate of silicone rubber increased from 604 degrees to 660 degrees, the highest degradation rate was only 0.123%?-1 and the quality of residue under 900 degrees was up to 78.6%. The silicone rubber added with mica had great strength after ablation at high temperature, when the content of mica was 30%, the three-point bending strength of sintered body was 5.10MPa. Mixing acicular wollastonite and mica could make silicone rubber get better performance, we could get the best comprehensive performance when the quality ratio was 7:3 and the total content was 60%.The effect of type and content of silane coupling agent on properties of ceramic silicone rubber before and after abalation were investigated. The results showed that the addition of KH550 could obviously improve the dispersity and wettability of ceramic filler in silicone rubber matrix compared to A151 and KH560, which improved comprehensive performance. When the addition of KH550 was 1.8%, silicone rubber performed best, however, increased the content continuously could result in bad performance.The effect of ablation temperature and ablation time on the strength of ceramic silicone rubber after abalation were investigated. The results showed that increasing the ablation temperature and prolonging the ablation time could help the formation and diffusion of liquid phase eutectic during the ablation process of silicon rubber, which made the strength of sintered body larger. The three-point bending strength of sintered body formed after abalation at 1000 degrees was 3.51 times as much as that at 600 degrees, and the three-point bending strength of sintered body formed after abalation at 800 degrees in 4 hours was 3.21 times as much as that in 15 minutes. When the temperature exceeded 1000 degrees or the time exceeded 60 minutes, the strength of sintered body had little change by increasing the ablation temperature and prolonging the ablation time continuously.