Preparation of polymer/clay mineral nanocomposites via dispersion of silylated montmorillonite in a UV curable epoxy matrix

Surface modification of clay minerals plays an important role for their application as fillers for polymeric materials. Among the many modification reactions, the silanization reaction uses alkoxysilanes and exploits the OH reactive sites of the montmorillonite structure. We found that using an excess of silane it is possible to functionalize the clay mineral and, at the same time, to intercalate some monomers or oligomers into the clay mineral galleries, greatly enhancing the interlayer distance. The montmorillonite modified in this way has been then used in the preparation of nanocomposite coatings by mixing it with a photocurable epoxy matrix. After UV irradiation the coatings obtained were submitted to morphological, thermal and mechanical analysis. The photopolymerization kinetics was also investigated. The introduction of the modified montmorillonite allowed to obtain transparent nanocomposite coatings characterized by a mixed intercalated/exfoliated structure and better thermal and scratch resistance performances in comparison with the montmorillonite free coatings.