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Characterization and Control of Airborne Particles Emitted During Production of Epoxy / Carbon Nanotube Nanocomposites
Journal article   Open access   Peer reviewed

Characterization and Control of Airborne Particles Emitted During Production of Epoxy / Carbon Nanotube Nanocomposites

Lorenzo G Cena and Thomas M Peters
Journal of occupational and environmental hygiene, Vol.8(2), pp.86-92
02/2011
DOI: 10.1080/15459624.2011.545943
PMCID: PMC4778245
PMID: 21253981
url
http://doi.org/10.1080/15459624.2011.545943View
Open Access

Abstract

This work characterized airborne particles that were generated from the weighing of bulk, multi-wall carbon nanotubes (CNTs) and the manual sanding of epoxy test samples reinforced with CNTs. It also evaluated the effectiveness of three local exhaust ventilation (LEV) conditions (no LEV, custom fume hood, and biosafety cabinet) for control of particles generated during sanding of CNT-epoxy nanocomposites. Particle number and respirable mass concentrations were measured using an optical particle counter (OPC) and a condensation particle counter (CPC), and particle morphology was assessed by transmission electron microscopy. The ratios of the geometric mean (GM) concentrations measured during the process to that measured in the background (P/B ratios) were used as indices of the impact of the process and the LEVs on observed concentrations. Processing CNT-epoxy nanocomposites materials released respirable size airborne particles (P/B ratio: weighing = 1.79; sanding = 5.90) but generally no nanoparticles (P/B ratiô1). The particles generated during sanding were predominately micron-sized with protruding CNTs and very different from bulk CNTs that tended to remain in large (>1 μm) tangled clusters. Respirable mass concentrations in the operator’s breathing zone were lower when sanding was performed in the biological safety cabinet (GM = 0.20 μg/m 3 ) compared to those with no LEV (GM = 2.68 μg/m 3 ) or those when sanding was performed inside the fume hood (GM = 21.4 μg/m 3 ; p-value < 0.0001). The poor performance of the custom fume hood used in this study may have been exacerbated by its lack of a front sash and rear baffles and its low face velocity (0.39 m/sec).
CNT nanocomposite exposure assessment respirable mass concentration Multi-wall carbon nanotubes

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