Evaluating Stability and Structural Changes of Nanocomposites and Developing Methods to Evaluate the Release of Nanoparticles

E. Sahle-Demessie, A. Zhao, H. Grecsek
U.S. Environmental Protection Agency, US

Keywords: nanocomposite, aging, nanorelease, TGA

Summary:

The increase in structural breakdown and possible release of nanoparticles from composites caused by brittling of the matrix material is being analyzed using thermogravimetric analysis (TGA) coupled with gas chromatography mass spectrometry (GC-MS), and the changes in glass transition temperatures using a differential scanning calorimeter (DSC). To provide insight to the stability and kinetics of structural changes of UV weathering, measurement of the light emitted through chemoluminescence is used to determine the concentration of the excited polymer matrix elements. These results are compared with other characterization techniques, fourier transform infrared spectroscopy (FTIR), electron microscopy (SEM and TEM) and x-ray diffraction analysis, x-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM), to measure changes with increase dose of uv-light. The release of nanomaterial to water and gas phase will also be measured. Metal based nano materials in air or rain wash will be determined using Single Particle ICP-MS (SP-ICP-MS), and lyophilized samples will be analyzed by TEM. Tests are made to simulate the release of nanoparticles during wash cycles of textile nanocomposite (mostly polyamids) that have been environmentally aged.