Study On Ceramifiable Silicone Rubber Composite Materials

The properties of ceramic silicone rubber composite materials are as same as the ordinary polymer materials at room temperature, but can become into ceramics in a high temperature environment which is capable of forming a self-supporting structure and even can withstand a certain force erosion. The discovery of the material is a breakthrough in the field of fire retardant and high temperature protection. Because of its processing and molding conditions are very similar to those of conventional polymer materials, even the equipments can be used in general which makes it have a good industrial application prospect and develop very rapidly.In this paper, a formula of porcelain silicone rubber composite with good comprehensive performances was studied. The recipe of the material which composed of constitution controller A, constitution controller B, constitution controller C, benzoyl peroxide(BPO), lithium carbonate, alumina, white carbon black, wollastonite and hydroxy silicone oil could obtain excellent mechanical properties and porcelain performances. The material can be used for fire retardant cables to ensure the fire wire and cable insulated and avoid short circuit accidents.By single factor experiments and orthogonal experiments investigated the influence of the substance dosage formulation on the material properties, got the optimal experimental formula composed of: alumina 8 parts, 15 parts of wollastonite and 13 parts of constitution controller A, 7 parts of constitution controller B, 11 parts constitution controller C, lithium carbonate 4 parts, BPO 2 parts, 4 parts of hydroxyl silicone oil. Examined the influence of components on tensile strength?elongation at break and the compressive strength of 600? ablation residue, the results showed as follow: the influence of tensile strength in descending order were: alumina> BPO> wollastonite > constitution controller B > lithium carbonate > constitution controller C > constitution controller A; the influence of elongation at break of the order of descending were: BPO > constitution controller A > alumina > constitution controller B > constitution controller C > wollastonite > lithium carbonate; the influence of the compressive strength of 600? ablation residue in descending order: constitution controller C > wollastonite > alumina > constitution controller A > constitution controller B > lithium carbonate > BPO.The tensile strength of materials prepared of the optimal formulation was up to 5.473 MPa, and the elongation at break was up to 305.667%, the compressive strength of 600? and 800? ablation residue were 4.663 MPa and 10.003 MPa, Shore A hardness was 51.333 degrees. By environmental scanning electron microscopy(SEM), X-ray spectroscopy and thermal analysis,we found that the ceramic mechanism differed depending on the temperature. At 600?, the role of porcelain was due to the liquid phase melted by partial porcelain filler adhered particles, while at 800?, performance of porcelain was partly of the molten liquid adhesive effect of porcelain filler, at the same time, there was a eutectic reaction to form a bond between the particles, and the new crystalline made structure denser.The silicone rubber composite materials studied in the thesis was with wide porcelain temperature range and low temperature ceramic(600?).The volume resistivity of its ablation residues at 1013?·cm or more, and met the requirements as porcelain insulating material.