| Ceramic silicone rubber fire-resisting material has been proved to be a new fireproof composite. The new type of flame retardant material consists of silicone rubber as the base polymer, to which inorganic clay filler, dispersant agent and other additives are added. The behaviors of ceramifiable composite are similar with common polymer in normal temperature while in high temperature or in flame it converts into a rigid ceramic protective layer. This protective layer plays an important role in cutting off the flame, thus ensures the normal transmission of communication and power under fire conditions. Thus, it is very important to develop a low-cost ceramifiable silicone rubber composite with excellent comprehensive proterties, such as mechanical properties, sintering and fame retardancy properties. This paper prepared a series of ceramifiable and flame retardant silicone rubber composites by using silicone rubber as the base polymer, to which different types of inorganic fillers, fluxing agent and flame-retardant fillers were added. Finally, ceramifiable and flame retardant silicone rubber composites with excellent comprehensive proterties were prepared and the effect of various fillers on the comprehensive proterties of silicone rubber composites was investigated.1、Silicone rubber composites(SR-composites) were prepared using frits and five different inorganic fillers(Kaolin, Sericite, Bentonite, Alumina and Aluminum hydroxide). The effect of the treatment of fillers, the types of fillers and the amount of fillers on comprehensive proterties of silicone rubber composites was explored. The results revealed that the treatment of inorganic fillers highly improved the mechanical properties of SR-composites and composite with treated kaolin showed the best tensile properties(8.59Mpa). Residues at 950℃ showed better sintering properties than 650℃ while greater volume shrinkage of different residues occurred at 950 ℃. The residue of sericite filled SR-composites exhibited the highest compress strength(1835N), which was 15 times larger than 650℃(123N). Kaolin and sericite filled ceramifiable SR-composites showed the outstanding mechanical properties, electrical insulation properties and sintering properties.2、SR-composites were prepared using kaolin and four different fluxing agent(Frits, Glass fiber, Zinc borate, Zinc oxide). The effect of the types and the amount of fluxing agent on the SR-composites before and after pyrolysis was explored. The results revealed that the strength of residue greatly increased with the amount of frits, glass fiber and zinc borate increased. SR-composites with frits as fluxing agent showed the excellent mechanical and sintering properties. When the amount of frits was 20 phr, a hard and compact ceramic body with porous structure was obtained. The mechanical porperties of SR-composites were decreased a lot with the addition of glass fiber while the compress strength of residue was the highest of the four fluxing agent(1856N) and the volume shrinkage of the residue was 25.96%. The tensile strength of zinc borate filled SR-composite was 7.11 Mpa. The compress strength of the residue with 20 phr zinc borate was 919 N and the XRD tests proved the formation of spinel in the residues. The mechanical and sintering properties of zinc oxide filled SR-composites were unsatisfactory compared with other three fluxing agent, the tensile and compress strength were 7.26 Mpa and 177 N.3 、 The ceramifiable and flame retardant SR-composites with excellent comprehensive proterties were prepared by filling sericite, zinc borate, platinum catalyst and different types of fire retardant. The effect of the types and the amount of fire retardant on mechanical, sintering and flame retardant properties of the SR-composites was explored. The results revealed that the level of vertical burning of SR-composites with 30 phr ATH/MH reached FV-0 while the tensile strength of composite was 7.95 Mpa, elongation at break was 150%, compress strength of residue was 1230 N. When filling 30 phr MCA/MPOP, the level of vertical burning of SR-composites also reached FV-0 while the tensile strength of composite was 6.04 Mpa, elongation at break was 280%, compress strength of residue was 546 N. The ceramifiable and flame retardant SR-composites with LDHs exhibited the excellent comprehensive proterties. When filling 20 phr LDHs, a hard and compact ceramic body was obtained. The level of vertical burning of SR-composites reached FV-0 while the tensile strength of composite was 7.32 Mpa, elongation at break was 220%, compress strength of residue was 1102 N. |
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