Preparation of a novel epoxy/SiO₂ hybrid coating

In this paper, epoxy/SiO₂ hybrid coating was successfully prepared through sol-gel technique, the structure and thermal properties of epoxy/SiO₂ hybrid coating were investigated. First, γ-isocyanatopropyltriethoxysilane " (KBE-9007) " was used to modify the epoxy resin so that the ethoxysilane could be grafted on the epoxy resin. Nano-SiO₂ precursor was synthesized by tetraethoxysilane(TEOS) through sol-gel technique. Then the modified epoxy resin and the nano-SiO ₂ precursor were mixed for 4 hours to let the macromolecules of epoxy resin graft on the surface of nano-SiO₂, and modified nano-SiO ₂ precursor was obtained. At last, epoxy/SiO₂ hybrid coating was produced by using the modified nano-SiO₂ precursor. The graft reaction was confirmed by the analyses of FT-IR. The analyses of XPS indicated that there are lots of SiO₂ particles and Si-C covalent bonds on the surface of epoxy/SiO₂ hybrid coating, they also suggested that most TEOS had changed into SiO₂ particles and Si-C covalent bond had been formed between epoxy resin and SiO₂. The analyses of SEM fracture surface image of epoxy/SiO₂ hybrid coating showed that SiO₂ particles dispersed in epoxy matrix homogeneously and the size of the particles was between 50nm and 100 nm. Thermoanalysis Instrument was employed to detect the thermal properties of epoxy coating and epoxy/SiO₂ hybrid coating, the results indicated that the thermal decomposition temperature of epoxy/SiO₂ hybrid coating is 21.7 °C higher than that of epoxy coating, the thermal properties of the epoxy/SiO ₂ hybrid coating were improved because of the introduction of nano-SiO₂.