Quantifying Photo-Induced Released Nanoparticles from Nanosilica/Epoxy Composites

L. Sung, D. Stanley, C-C Tien, J. Gorham, S. Rabb, L.L. Yu, T. Nguyen
National Institute of Standards and Technology, US

Keywords: environmental health and safety, nanoparticle, photodegradation, UV

Summary:

Nanoparticles are increasingly used in polymer composites to improve properties of traditional composites such as mechanical, electrical,and UV resistance. These high performance nanocomposites are often used in outdoor environments. However, because polymers are susceptible to degradation by weathering elements, nanopartilces in composites may be released into the environments during the life cycle of a composites. Such release potentially poses an environmental health and safety (EHS) concern and may hinder commercialization of these advanced composites. This study presents protocols and experimental technique to quantify surface accumulation and release of nanosilica (SiO2) from nano-SiO2/epoxy system as a function of UV exposure. Specimens of epoxy/5 % SiO2 composites in specially-designed holders were exposed to 295-400 nm UV radiation in a well-controlled high-intensity UV chamber. UV irradiated specimens were removed at specified time intervals for measurements of chemical degradation, mass loss, accumulation of nanosilica on specimen surface, and nanosilica release as a function of UV dose. Results showed that material mass loss, chemical degradation, and silica accumulation on specimen surface increased with UV radiation dose. Results at four different temperatures will be presented.