Application of acrylic-based nanocomposites in the consolidation of historical enamel layers

Enamel is a special coating obtained from the mixture of powdered minerals, fluxes and various pigments. This coating is used on metal to protect it against corrosion. Enamel offers properties superior to those of traditional materials, including good chemical resistance, increased thermal and colour stability. Positive features of enamels have been noted by artists, which resulted in the development of various decorative techniques. These embellishments were characterised by the highest level of artistry. However, enamel is also a very brittle material; mechanical strain or rough handling may cause cracking or exfoliation. To control these effects, the damaged structure of historic enamel is filled with an agent which stabilises it against breaking stress, whether between the coating and the metal or in the enamelling layer itself. Presented are the results of research on the consolidation of enamel by means of nanocomposites. The polymer matrix applied was acrylic resin (Paraloid). The filler was Aerosil 200 fumed silica modified by 3-methacryloxypropyltrimethoxysilane. Selected properties of the polymer/filler composition were measured, including adhesion, hardness and flexibility. It was observed how the addition of a modified filler to acrylic resin changed its properties. Relative to the initial properties of the resin, the differences in the adhesion between the composite and glass (enamel imitation) or the composite and metal indicate interactions between the composite and the metal or glass substrate.