Characterization of Released Particles on the Surface of a Weathered Nanosilica/Polyurethane Coatings after Abrasion

摘要

Objective of this study is to understand the mechanism and process of nanoparticle release from nanocoatings under different environment stresses. A commercial PU coating having 5 % mass fraction of nanosilica was selected. Specimens were exposed in a well-controlled high-intensity UV environment at 50 °C and approximately 0 % relative humidity. After UV expoure, a mechanical abrasion test method was applied to induce particles release from UV exposed nanocoatings. Laser scanning confocal microscopy (LSCM) and atomic force microscopy (AFM) were used to characterize the surface morphological changes and nanoparticle accumulation on the coating surface at different exposure times. After abrasion, the number and size distribution of released particles on the abraded surfaces were also quantified using LSCM with image analysis. The effect of UV expsoure time on the surface mechanical properties under abrasion will be examined and mechanical-induced particle release (through Si mass) will be quantified using inductively coupled plasma-optical emission spectroscopy (ICP-OES) and compared to the release results via simulated rain method from the same coating system.