Nanoparticles are increasingly used in consumer and structural polymeric products to enhance a variety of properties. Under the influences of environmental factors (e.g., ultraviolet, moisture, temperature) and mechanical actions (e.g., scratching, vibrations, abrasion), nanoparticles might release from the products and thus potentially have negative effects on the environments, health and safety. The fate of nanoparticles in polymer nanocomposites during their exposure to UV environment has been investigated. Epoxy polymer containing multi-walled carbon nanotubes (MWCNTs) and silica nanoparticles were studied. Specially-designed cells containing nanocomposite specimens were irradiated with UV between 295 nm and 400 nm in a well-controlled UV chamber. Chemical degradation, mass loss and surface morphology of the epoxy nanocomposites, and release of nanoparticles were measured. Epoxy containing MWCNTs exposed to UV radiation degraded at a much slower rate than the unfilled epoxy or the epoxy/nanosilica composite. Photodegradation of the matrix resulted in substantial accumulation of nanoparticles on the composite surfaces. Silica nanoparticles were found to release into the environment, but MWCNTs formed a dense network on the composite surface, with no evidence of release even after prolonged exposure. Conceptual models for silica nanoparticle release and MWCNT retention on the surface during UV exposure of nanocomposites are presented.
Proceedings Title: Nanosafe2010
Conference Dates: November 16-18, 2010
Conference Location: Grenoble, -1
Pub Type: Conferences
EHS, fate, life cycle, nanoparticles, release, UV, polymer nanocomposites