Preparation And Characterization Of Silicone/SiO₂ Hybrid Material

Organic/inorganic hybrid materials possess combinations of the properties of both organic and inorganic materials, which render it promising materials for coating. In this paper, tetraethyl orthosilicate (TEOS) as inorganic precursor, methyl triethoxysilane (MTES) and diphenyl dimethoxy silane (DDS) as organic precursor, silicone/SiO₂ hybrid materials was synthesized by sol-gel method. An organic /inorganic hybrid nano material was synthesized by adding nano-TiO₂ in silicone/SiO₂ hybrid materials, and the various properties of the coating prepared by nano-TiO₂ in silicone/SiO₂ hybrid materials were tested. The results showed that the coating exhibited excellent corrosion resistance and heat resistance. Meanwhile, this coating showed good protectiveness in hydrothermal and mildew environment. The results of these experiments listed as follows:1. The optimum volume of TEOS, MTES and DDS for synthesizing hybrid sols process was obtained by evaluating of hybrid coatings physical properties and heat resistance. The amount of organic silicon monomer molar ratio was determined as n(TEOS):n(MTES):n(DDS)=6:9:1. By judging gelling time of the hybrid sols, the best molar ratio of reactants used for preparing hybrid materials between the addition of EtOH, H₂O, HC1 and organic silicon monomer were determined as n(HCl): n(H₂O): n(EtOH):n(Si) = 0.0025:2:2:1, and the curing conditions of preparation hybrid materials was obtained.2. Silicone/SiO₂ hybrid materials with different content of SiO₂ have been prepared by sol-gel method. The infrared spectrum (FT-IR) showed that organic and inorganic dual-phase formed a strong interaction in all hybrid materials although they were prepared by the different content of TEOS. Heat-resistance was investigated by Thermo Gravimetric Analysis (TGA) and heat-resistance test. Corrosion-resistance was studied by electrochemical impedance spectroscopy (EIS), immersion test and salt spray test. The results show that the thermal decomposition temperature of the hybrid coating were increased by 67℃, and its corrosion resistance was improved obviously by addition of a certain amount of TEOS.3. The samples which were prepared by the molar ratio of organic silicon monomer were n(TEOS) : n(MTES) : n(DDS) =6:9:1 were immersed in 3.5% NaCl solution for different time and studied by electrochemical impedance spectroscopy (EIS). The equivalent circuits were established according to the impedance spectral characteristics. The mechanism of corrosion resistance of hybrid coatings has been discussed base on the equivalent circuit and fitted results of electrochemical impedance spectroscopy immersing in 3.5% NaCl solution for different times. The results indicate that the corrosion resistance of the hybrid coatings is excellent.4. By in situ polymerization and physical blending process, The TiO₂/silicone/SiO₂ hybrid materials with different content of TiO₂ were prepared by adding TiO₂ sol and powder nano-TiO₂ in silicon/SiO₂ hybrid sol, respectively. The infrared spectrum (FT-IR) showed that the Ti atoms in two types of hybrid materials are grafted to the hybrid network. The properties of TiO₂/silicone/SiO₂ hybrid coatings were studied. The results showed that the physical properties and corrosion resistance of the coating with lwt% of TiO₂ prepared by in-situ polymerization process showed better anti-mildew effects.