| An experimental setup was designed to measure and characterize the emission of particles during the sanding of composite materials containing carbon nanotubes (CNTs). The experimental setup consisted of a sand-blasting cabinet with HEPA-filtered air intakes. An electrical motor outside the cabinet was connected to a pulley through a v-belt. A material feeder with constant force was constructed. The system was tested with a belt sander by sanding 1) glass fiber/epoxy resin, 2) glass fiber/epoxy resin containing post-coated multi-walled carbon nanotubes (MWCNTs), 3) acrylonitrile butadiene styrene (ABS) 4), ABS containing MWCNTs, 5) ABS containing glass-fiber-infused MWCNTs, 6) ABS containing carbon black, and 7) ABS containing carbon black and MWCNTs. Total number concentrations, respirable mass concentrations, and particle size number/mass distributions of the emitted particles were measured using a scanning mobility particle sizer, an optical particle counter and a condensation particle counter . Additionally, samples for electron microscopy analysis were collected with a thermophoretic sampler and filter samples. Measurements were repeated with coarse (150 grit) and fine (320 grit) sandpaper. The addition of CNTs did not consistently increase particle emission for all of the materials, while the choice of sandpaper grit had a more consistent association with particle emission from the materials. Micron-sized particles with CNT-protrusions were observed on microscopy analysis. No free-standing CNTs were observed on microscopy analysis. |
