With modular, combinable building blocks, silicone can be produced at room temperature and under normal pressure for a variety of practical applications.
AG Wagner, Goethe University
Silicones have a wide range of applications from medical implants and cosmetics to hydraulic oils and sealants through to corrosion protection. To optimise silicon materials for specialised applications, made-to-measure chlorosilane building blocks are required in order to produce and crosslink the long-chain polymers. This influences the material's viscosity and flow properties, for example.
Professor Matthias Wagner's research group at the Institute for Inorganic and Analytical Chemistry from Goethe University has presented the process in the Journal of the American Chemical Society. This process has several advantages over the Müller-Rochow Direct Process and uses hexachlorodisilane and chlorinated hydrocarbons as starting materials. "Hexachlorodisilane is already mass-produced for the semiconductor industry and the perchlorethylene (PER) we use particularly frequently is a non-flammable liquid, which is so inexpensive that it’s used worldwide as a solvent for dry cleaning," explains Wagner. Furthermore, the process takes place at room temperature and under normal pressure and requires only a low concentration of chloride ions in place of a catalyst to activate it.
"Our process produces highly functionalised organochlorosilanes that are ideal crosslinkers. In addition, their special structure offers excellent possibilities to adjust the mechanical flexibility of the silicon chains as desired," explains co-inventor Isabelle Georg. The Frankfurt-based chemists believe that their monomers have special potential since they contain both silicon-chlorine bonds used to construct inorganic silicon-oxygen chains and carbon-carbon multiple bonds used to form organic polymers. This unique combination will open up new avenues for the development of inorganic-organic hybrid materials.