Anti-scratch and adhesion properties of photo-curable polymer/clay nanocomposite coatings based on methacrylate monomers

Different types of polymer/clay nanocomposite were prepared and evaluated for theirapplication as hard and anti-scratch coating materials. Photo-curable nanocomposites, based on 2,2-bis[4-(methacryloxypropoxy)-phenyl]propane (Bis-GMA (2,2-bis[4-(methacryloxypropoxy)-phenyl]propane))and tri (ethylene glycol)dimethacrylate (TEGDMA (tri(ethylene glycol)dimethacrylate)) (50/50 wt%) wereprepared using three types of clay at different loading levels. The adhesion properties and scratchresistivity of the coatings on polymethymethacrylate slabs were investigated. The results were correlatedwith the clay dispersion state, determined by a transmission electron microscopy, X-ray diffraction andthe surface morphology by atomic force microscopy. It was concluded that exfoliation or intercalationplays an important role, primarily in surface roughness, which in turn affects adhesion by changingthe characteristics of the coating-substrate interface. The highest scratch resistivity with appropriateadhesion quality was obtained for a sample containing 1 wt% of more compatible clay, Cloisite⃝R 30B inthe nanocomposite resin mixture.