Influence of nano-silica and polyethylene wax on the scratch behavior of acrylic-based polyurethane coatings

The scratch behavior and resistance of acrylic-based polyurethane coatings were studied. The effects of fumed silica and polyethylene wax were investigated using an area-contact scratch tip, which can apply a constant load to the coating surfaces at a relatively low stress level. Measurements of the normalized changes in gloss (%G(n)) and luminance (%L-n) could be provided as reliable and meaningful methodologies for estimating the scratch resistance and subtle damage to polymeric coating surfaces. A higher gloss-valued coating surface has better scratch resistance. The addition of nano-silica particles provides the increases in hardness, transparency, and resistance to scratch damage for the acrylic-based polyurethane surface, whereas the polyethylene wax contributes to the increases in gloss and smoothness for the coating surface. The surface characteristics observed are responsible for the improved scratch performance of the acrylic-based polyurethane coating surface.