Fundamental Study On RTV Silicone Rubber Used For Fip Electro-magnetic Shielding Conductive Rubber

Electromagnetic interference (EMI) is considered as a crucial environmental andreliability issue in electronic information industries, especially with the rapiddevelopment of information technology. Since electromagnetic signals are prone to beinterfered by external electromagnetic radiation, it is urgent to take effective measuresto reduce, or ultimately eliminate the electromagnetic interference. Electromagneticshielding conductive silicone rubber hence attracts great attention based on suchdemands.In this research, we report our fundamental studies on conductive polymercomposite materials, i.e., adding different conductive filler into polymer to achieverequired conductivity. More exactly, one component room temperature vulcanized(RTV-1) silicone rubber was used as the basic polymer materials and Ni/C particleswere utilized as conductive filler. Conductive polymer composite materials have beenwidely used in many different areas owing to its low cost and uncomplicatedprocessing techniques. In order to achieve better performance, the two maincomponents, silicone rubber and conductive filler, should both exhibit goodperformance and compatibility.The ketonic oxime type RTV-1silicone rubber currently available in the marketare mostly designed as the final product, the properties of which are alreadydetermined. Those products cannot be used for the preparation of conductivecomposite silicone rubber since the mechanical properties and processingperformance cannot meet the requirements. As one of the basic components to prepareelectromagnetic shielding conductive silicone rubber, the RTV-1silicone rubbershould exhibit optimum mechanical properties. Therefore after the addition ofconductive filler, the final product still has proper strength and elongation to meet theperformance requirements. Taking the processing performance into account, theviscosity and fluidity are also very important owing to the large amount of conductivefiller that should be added into the RTV-1silicone rubber. As the main additive, silicahas significant influence on the properties of final products. With the increase of silicacontent, the mechanical properties are improved whereas the viscosity is sharplyincreased, resulting in a decreasing fluidity. Therefore it is of great importance todetermine the optimal silica content via experiment and research in order to solve thecontradiction between mechanical properties and processing performance. The properties of RTV-1silicone rubber, the intermediate products, can be controlled byadjusting the processing parameter. In other words, the intermediate products can beprepared with different properties and performance according to the requirements offinal products.This paper is focused on the RTV-1silicone rubber. The attempt to improve theperformance of silicone rubber was based on the experimental efforts on formuladesign as well as processing improvement. The formula and processing of RTV-1silicone rubber with required performances was investigated from a series ofcomparative experiments. The influence of silica content of different type (fumedsilica and precipitated silica) on the performance of RTV-1silicone rubber wasrevealed from experimental results.85oC-85%RH aging,100oC aging, and salt spraytesting (SST) were different ways we employed to investigate the reliability of RTVsilicone rubber and conductive silicone rubber. Several aspects of service performancewere tested and characterized.