The Preparation Of Micro-porous Materials Of Liquid Silicone Rubber

The porous silicon rubber material has much excellent performance, such as low-density, high temperatures-resistence, noise-insulated, and others, which is widely used in the aerospace, electronic components, medical and other areas. The liquid silicone rubber porous materials are the main direction, because of its simple preparation, short cycle, and high efficiency.Now the study and preparation of the porous silicon rubber material has been done a lot, but the methods are only used two, which are chemical foam-method and physical foam–method, the latter is to add low boiling point solvents. Both of these two methods need long time to prepare, and the products'cells are mostly uneven and obturated. To solve the problems of these two methods, the most effective way is to use the particles leaching–method to prepare the opening-porous materials. So the controllability and uniformity of the porous cell's size can be achieved. The innovation of this study is to use particle leaching to prepare the liquid silicone rubber porous materials, this is a new preparation method at present.In this paper, the particles which always are NaCl are added in SC-8311AB silicone rubber to prepare liquid silicone rubber porous materials. The particles in porous materials will be leached in boiling water. We found that, with the content of the pore-forming agent increased: the number of the cell increased, the distribution of the pore-size was uniform and the product was a multi-porous system; the density of the porous materials reduced from 1 g/cm3 to 0.2658 g/cm3; porosity of the porous material change from 30% to 75%. The tensile strength of the porous material fell to about 0.3 MPa, the rate of the tear strength reduced much, from10 kN/m, down to 1 kN/m; the compression performance was improved, and the compressed flat area was much longer.In the process of preparing the porous materials, the silica nanotubes is used as reinforcing filler to adjust the mechanical properties, when the content of the pore-forming agent is three times of the silicon rubber, the tensile strength in 2 percent reaches the maxium- 4.059 MPa, and the tear strength in 3 percent reaches the maximum, but this can damage the compressibility of the porous materials, and the flat area of compression becames short. The structure of this porous material has good compressibility, which can be used as a kind of material to damper and prevent earthquakes. Although the mechanical properties of this porous material has dropped, which can be greatly improved, and applied widely by filling reinforced material.In this paper, the research and exploration of the liquid silicone rubber conductive composite material have been done, such as adding carbon fiber, graphite, carbon nanotubes conductive fillers, but the results was not so well as we expected before.