Silicone-acrylic hybrid aqueous dispersions of core–shell particle structure and corresponding silicone-acrylic nanopowders designed for modification of powder coatings and plastics. Part III: Effect of modification with selected silicone-acrylic nanopowders on properties of polyurethane powder coatings

Abstract

Abstract Polyurethane powder coating systems consisting of polyester resin, blocked polyisocyanate and two types of “nanopowders” containing core–shell nanoparticles where the core was silicone resin of very low glass transition temperature and the shell was poly(methyl methacrylate) were examined. The blocked polyisocyanate was synthesized using biuretpolyisocyanate obtained from ureapolyisocyanate as starting material capable for blocking and ɛ-caprolactam as blocking agent. The surface properties of cured powder coatings were investigated using scanning electron microscopy (SEM) combined with energy dispersive spectrometry (EDS), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The surface structure was correlated with the chemical structure of the coatings and macroscopic surface behavior: contact angle, surface free energy, gloss, abrasion resistance, hardness and adhesion to the steel surface.