Influence of Sol-Gel Derived Nanosilica on the Structure and Properties of Epoxy Composites and Coatings

Abstract

Using Raman spectroscopy, the features of the hydrolytic polycondensation of tetraethoxysilane (TEOS) with free access of air, as well as the effect of catalytic and excess amounts of the polyether amine Jeffamine T-403 on this process are studied. This amine was used as a curing agent to obtain a pure epoxy polymer and form a polymer matrix of the composite modified with silicon dioxide (2 wt %). Low-viscosity epoxy oligomer Eponex 1510 was used as a polymer binder. Thermophysical properties of film samples of the polymer and composite under tensile and bending loads were studied in detail. Based on TMA and DSC data, parameters characterizing the topological structure of the samples were determined. The effect of silica on the segmental mobility of interstitial chains of the network composite was established, which leads to an increase in the glass transition temperature by 10–16°C and a decrease in the relative deformation of the sample. Thermogravimetric studies have shown that the presence of silicon dioxide in the composite reduces the maximum rate of mass loss of the composite. The resulting composite coatings on the surface of the D16 aluminum alloy retain their integrity under prolonged exposure to salt fog, unlike coatings based on unfilled epoxy polymer.