Nanoparticles such as carbon nanotubes are increasingly added to polymer matrices to improve tensile strength electrical and thermal conductivity and to reduce gas permeability. During use and after disposal these plastic nanocomposites (PNCs) will be degraded into microplastics by physical and chemical processes including mechanical abrasion UV light exposure hydrolysis and oxidation. Such polymers have the potential to enter aquatic environments and release potentially hazardous polymer associated chemicals and transformation products. This work identifies and quantifies polymer associated chemicals leached from polymers and nanocomposites during simulated environmental exposure. Epoxy and polycarbonate PNCs containing single-walled carbon nanotube (SWCNT) loadings ranging 0 % to 1 % wt. were exposed to water for 5 days and the release of the chemicals bisphenol A (BPA) and 4-tert-butylphenol (TBP) was measured. The role of UV exposure pH temperature and natural organic matter (NOM) in regulating chemical release was also investigated. Temperature pH and UV light were found to be the most significant factors influencing release of TBP and BPA from PNCs. Additionally increasing carbon nanotube loading in both polycarbonate and epoxy composites was found to decrease the release of these phenolic chemicals. A 0.3% higher SWCNT loading decreased the release of BPA 45 ± 18% and a 1% SWCNT loading decreased chemical release from epoxy by 48 ± 26% for BPA and 58 ± 8% for TBP respectively. This information provides important data that can be used to help assess the risks posed by SWCNT polymer nanocomposites in aqueous environments particularly as they age and are transformed.
