The effect of α-alumina filler/acrylic–melamine polymer interfacial interactions on the abrasion resistance of an automotive topcoat layer

The study of the effect of interfacial interactions on the abrasion properties of a selected automotive topcoat system has been undertaken. This was achieved by using a fixed patch of abrasive rubbing on a flat rotating disc coated with a layer of test material. The interactions that arise in acrylic–melamine/alumina assemblies were the subject of this investigation. The alumina particles had different surface treatments and were introduced to the polymeric matrix at four different loading levels. In general, it was found that there is a strong correlation between the abrasion resistance, and both the α-alumina loading level and the nature of surface treatment given to the alumina particles. The α-alumina particle with a surface treatment of p-hydroxy benzoic acid (PHBA), gave improved abrasion resistance, relative to the untreated particle, where functionalization of the surface with an alkyl benzene sulphonic acid (ABSA), decreased the abrasion resistance of the coating system. The differences were attributed to the effect of surface treatment on the interaction between the hard particle and the matrix.