| In order to reduce the damage to life and property in our daily life, which caused by fire, fire retardant materials becomes the key point. By adding halogen-containing flame retardants such as pentabromophenyl, it releases a lot of toxic and hazardous fumes during the combustion process despite its excellent flame retardant effect, which was forbidden by domestic environmental law. Now the main choice is LSZH rubber products, such as silicone rubber, ethylene propylene rubber, ethylene vinyl acetate rubber, which may work well under fire, but can’t keep its strength and maintain the structure during a long-time use. That might lead the next occurrence of secondary damage, so its wider application is limited. As a kind of fire retardant material, ceramizable silicone rubber composite has made a wide range of applications in the field, and expected to have a further value. In this paper, ceramizable silicone-based composite was prepared by using VMQ as matrix and Kaolin as additives, the ceramifying reaction can occur at high temperature and become a self-supporting structure of the ceramic body.In this paper, caramizable silicone rubber was prepared by adding Kaolin to VMQ. TG-DSC test showed that thermal stability was significantly improved as Kaolin added. When the addition of Kaolin was 40wt%, the residual rate was 50.23%, while the pure VMQ was 37.33%. As low melting point glass powder added, the TG-DSC analysis showed that T5 and Tmax of the material were both reduced a lot. The T5 was lowered to 3870 C from 4170 C, and Tmax is reduced in the range of 50~700C, even dropped from 512.40 C to 446.90 C. SEM results showed that Kaolin/frits/VMQ start the organic-inorganic transition at 8000 C, the surface is intact and there is no obvious cracks or voids. Scanning electron microscopy analysis showed within the softening temperature range, there were many continuous molten pellets, which were proved glass powder by EDS, they helped to bond the matrix and additives. According to the caramazation behavior, wollastonite and larnite were achieved at 600~8000C from CaO and SiO2, and endothermic at 7030 C for metakaolin, then heated into mullite and finally appeared the emergence of diffraction peaks CaAl2O4 at 12000 C.Zinc borate was added as an alternative solvent to prepare the ceramizable silicone rubber composites. By TG-DSC analysis, residual increased to 57.63wt% as the addition of ZB was 15wt%, which was higher than Kaolin/frits/VMQ. T5 and Tmax were slightly lower, but don’t as obvious as Kaolin/frits/VMQ was. SEM showed the interior part became dense, homogeneous lattice-shaped from about 6000 C, and more obvious at higher temperature, and showed significant change in densification at 8000 C. There appeared some new molten liquid phase at 10000 C, and were proved “eutectic” by EDS spectrum analysis, which could combine silica with Kaolin filler well, act as a “bridging” effect, and that could cured under ignition point, the ceramic structure could formed after the strip cooling, and the maximum strength was obtained at this temperature. In this case, the structure was complete and the surface crack is minimal.High silica glass fiber was added as a reinforcing material, which can effectively improve the thermodynamic property of silicone rubber. When glass powder was added, the residual rate increased from 54.00% to 63.00%, and the other group which added ZB also increased from 57.63% to 65.12%. The flexural strength of two groups were both improved significantly after 6000 C, and the maximum were 1.89 MP, 2.01 MPa, which increased 1.19 MPa, 1.22 MPa, compared with fiber enhanced before. |
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