Authors: S.A. Rabb, L.L. Yu, T. Nguyen
Affilation: National Institute of Standards and Technology, United States
Pages: 728 - 731
Keywords: nanosilica release, composite films, ICP-OES
Silica nanoparticles are being utilized to enhance the mechanical performance of polymeric coatings used in automotive and construction industries. However, cumulative effects of UV radiation will degrade the polymeric molecules, resulting in a potential for release of the nanoparticles into the environment. As part of a study on the environmental fate of nanoparticles in polymer nanocomposites, three films, containing different mass fractions (0 %, 5 % and 10 %) of silica nanoparticles, have been subject to controlled degradation conditions at specified humidity, temperature, and UV radiation doses over a period of 59 days. To determine the rate of release, an analytical method is being developed to selectively attack silica nanoparticles on the surface of the film without extracting nanoparticles from the interior. Variable concentrations of hydrofluoric acid (HF) have been investigated to optimize this dissolution process. The mass fraction of nanosilica in the extracted solutions is measured by inductively coupled plasma – optical emission spectroscopy (ICP-OES). Multiple sections of the film are analyzed to determine repeatability of release for each film. The results of this study will assist in establishing a reliable and sensitive method for measuring the release rate of silica nanoparticles from UV-irradiated polymer nanocomposites.