Study On Dielectric And Fire Resistance Properties Of Ceramizable Silicon Rubber

With the use of wires and cables has increased year by year,and the hidden fire hazards caused by them have become increasingly prominent.If a fire occurs,it will cause huge economic losses.For new fire-resistant cables,extruded flame-retardant protective sleeves can be used for protection.For power cables that have been put into operation,how to improve their fire-resistant performance on the spot has become an important research direction.In this study,ceramizable silicone rubber composites were prepared by melting blending method.The amount of flux,flame retardant,reinforcing agent,ceramic filler and the modification of the matrix resin on the ceramizable silicone rubber composite were studied.The effects of the amount of flux,flame retardant,reinforcing agent,ceramic filler and modification of matrix resin on the tensile properties,electrical properties and flame retardant property of ceramizable silicone rubber composites were studied.And further studied the dynamic combustion performance of the composite material and the porcelain-forming effect of the sintered ceramic body,and explored its fire and flame retardant effect from multiple angles.In this paper,the tensile properties of composite materials are tested,and the research is carried out from two perspectives of elasticity and plastic deformation.The results show that with the increase in the amount of flux glass powder and zinc borate,the compatibility of the flux with the matrix deteriorates,and the plastic deformation and plastic deformation properties of the material have decreased.The Si O₂ is uniformly dispersed in the silicone rubber matrix,which increases the compactness of the filler network structure,enhances the interaction force between the molecular chains,and increases the elastic deformation performance and tensile strength of the composite material.The blending of EVA and silicone rubber is a rubber-plastic blending system.EVA modifies the silicone rubber from a physical level.The molecular chains of EVA and silicone rubber are intertwined with each other,which makes the filler structure more stable and improves the elastic modulus and plastic deformation properties of the composite material.By the materials’volume resistivity and breakdown field strength testing to characterize its electrical properties,the results show that the addition of flux introduces more impurity ions,which weakens the binding of free electrons,and makes the volume resistivity and breakdown field strength of the composite material decrease.With the increase in the amount of Si O₂,the filler network structure is gradually compacted,that limits the migration of carriers and the movement of free electrons,leading the increase of the resistivity and breakdown field strength of the composite material.The addition of EVA changes the continuous phase distribution state of the silicone rubber,thereby affecting the dispersion state of the filler in the matrix,causing the filler to accumulate locally,which is conducive to the transition of carriers,and the volume resistivity of the sample decreases.At the same time,the interface force is attenuated,that result in the sample is more prone to breakdown.An excessive amount of flame retardant ceramic powder can lead to defects inside the material,the interface damping force,a strong decrease in breakdown field sample.Combustion property of ceramizable silicone rubber composites were tested.The results show that the flame retardant property of the material gradually increases with the increase of the filler.When the amount of glass frit/Si O₂ is 40/40,the oxygen index of the material is the highest While the peak heat release rate and the peak smoke generation rate of the sample are reduced,the fire performance index is improved,and the fire risk is reduced.After the sample burns,a stronger expanded carbon layer is formed on the surface of the sample,which can play the role of smoke suppression,heat insulation and oxygen barrier.The sample can maintain the basic shape after high temperature sintering,and the increase in the amount of flux and reinforcing agent will help the integrity of the ceramic body sample structure after sintering,and there will be less surface cracks.