Sol-gel composite coatings from methyltriethoxysilane and polymethylhydrosiloxane

New composite coatings were prepared by mixing pre-hydrolyzed methyltriethoxysilane (MTES) sol by an acidic catalyst dibutyltin dilaurate (DBTDL) and polymethylhydrosiloxane (PMHS) in gasoline at room temperature. The gel process was thoroughly investigated regarding the use of different basic catalyst [3-aminopropyltriethoxysilane (APTES) or triethylamine (TEA)], as well as the ratios of pre-hydrolyzed MTES sol and PMHS with various content of active H. It was revealed that the composite coating from 2:1 ratio (w/w) of pre-hydrolyzed MTES sol with equimolar amounts of water and PMHS1.55 under the catalysis of APTES demonstrated high pencil hardness, and excellent resistance against contamination and corrosion. This composite coating (MTPM21-A) was further characterized by FTIR, Si-29 NMR, DSC and TGA.