A comparative study on the effect of type of reinforcement on the scratch behavior of a polyacrylic-based nanocomposite coating

In this article the effects of type of reinforcement on the scratch behavior of nanocomposite coatings are studied. Such coatings can be used in the automotive industry as clear top paint coats. Three types of reinforcements were used, including detonation nanodiamond, nondetonation nanodiamond, and nano-alumina, with an average particle size of 4–6, 50–60, and ~50 nm, respectively. Nanocomposites containing 1.5 and 3 wt% of each filler type in polyacrylic as matrix were produced by sonication. The macrostructure, microstructure, and scratch behavior of coatings were investigated and compared with those of neat polyacrylic polymer. The scratch behavior was evaluated based on the ASTM G171 standard and also by common industrial tests such as the pencil hardness test. The results revealed that the nano-alumina coatings showed the best, and the nondetonation nanodiamond coatings the worst, scratch resistance—even less than that of the neat polyacrylic polymer.