A novel type nanocomposite coating based on alkyd-melamine formaldehyde resin containing modified silica: Preparation and film properties

Abstract

In this study, the surface of the silica particles was modified with glycidoxypropyl trimethoxysilane and then silica nanoparticle modified alkyd-melamine resins were synthesized by two methods, namely in situ (IS) polymerization and blending (BL) methods. After alkyd resins containing 40% oil were prepared; these resins were blended with 30% of a commercial melamine-formaldehyde. The films of the alkyd-melamine formaldehyde resins were prepared from 60% solid content in xylene solutions. These films were cured at 170 degrees C and properties of the films were determined. The effect of modified silica on the film properties and thermal behaviors of the resins was investigated. The scanning electron micrographs of the nanocomposite resin showed that modified silica particles have been dispersed into polymer resins substantially for IS polymerization. According to results of surface coating tests, we can say that, film properties of the resins prepared by IS method were better than that of prepared by BL method. In addition, using modified silica did not have a negative effect on the thermal behaviors of the resins with respect to thermogravimetric analysis. Furthermore, adding the modified silica in the resin structure caused increasing the thermal stability especially for resins prepared by IS method. As a result, alkyd-melamine resins containing modified silica nanoparticle are suitable for manufacturing of industrial baking enamels. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012