(8d) A Model of Surface Indentation of Polymer Composites

Composite coatings are prepared either by a dip coating or by extrusion or by web coating processes. After wet coatings are dried, defects can emerge depending on the drying conditions of time and temperature. The surface defects affect charging and adhesion to the coating surface and wear of coatings. Coatings of polycarbonate and polyester with additives were made on aluminum surfaces. The coatings were characterized for tensile modulus and hardness using a Hysitron nanoindenter. Drying time and temperature affected quality of coatings and defects on the coatings which in turn affected the modulus and hardnness of the coatings. Effect of diaryl amine additives in polycarbonate resulted in increasing Young’s modulus, reducing glass transition temperature but making the surface more brittle and reducing fracture toughness..  Composite modulus and hardness was analyzed as a concentration of diaryl amine and interaction parameters between the polymer matrix and the additive interface. These results are compared and contrasted with silica in polycarbonate and polyester matrixes.