Characterization of Exposures To Nanoscale Particles and Fibers During Solid Core Drilling of Hybrid Carbon Nanotube Advanced Composites

Bello, Dhimiter; Wardle, Brian L.; Zhang, Jie; Yamamoto, Namiko; Santeufemio, C.; Hallock, Marilyn F.; Virji, M. Abbas

doi:10.1179/107735210799159996

Cited by 54 publications

(30 citation statements)

References 13 publications

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“…Sawing, drilling, and sanding of composite materials containing CNTs can release both fine and nanoscale particles with peak concentrations as high as 8380 μg/m 3 being reported during the dry cutting of composites in the absence of exposure controls. 7,8 Methner et al 9 measured peak airborne particle concentrations 2-64 times higher than office area levels during weighing and mixing of CNFs. These airborne particles included loosely agglomerated CNFs.…”

Section: Workplace Exposures To Cnts or Cnfsmentioning

confidence: 99%

Occupational Nanosafety Considerations for Carbon Nanotubes and Carbon Nanofibers

2012

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CONSPECTUSCarbon nanotubes (CNTs) are carbon atoms arranged in a crystalline graphene lattice with a tubular morphology. CNTs exhibit high tensile strength, possess unique electrical properties, are durable, and can be functionalized. These properties allow applications as structural materials, in electronics, as heating elements, in batteries, in the production of stain-resistant fabric, for bone grafting and dental implants, and for targeted drug delivery. Carbon nanofibers (CNFs) are strong, flexible fibers that are currently used to produce composite materials.Agitation can lead to aerosolized CNTs and CNFs, and peak airborne particulate concentrations are associated with workplace activities such as weighing, transferring, mixing, blending, or sonication. Most airborne CNTs or CNFs found in workplaces are loose agglomerates of micrometer diameter. However, due to their low density, they linger in workplace air for a considerable time, and a large fraction of these structures are respirable.In rat and mouse models, pulmonary exposure to single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), or CNFs causes the following pulmonary reactions: acute pulmonary inflammation and injury, rapid and persistent formation of granulomatous lesions at deposition sites of large CNT agglomerates, and rapid and progressive alveolar interstitial fibrosis at deposition sites of more dispersed CNT or CNF structures.Pulmonary exposure to SWCNTs can induce oxidant stress in aortic tissue and increases plaque formation in an atherosclerotic mouse model. Pulmonary exposure to MWCNTs depresses the ability of coronary arterioles to respond to dilators. These cardiovascular effects may result from neurogenic signals from sensory irritant receptors in the lung. Pulmonary exposure to MWCNTs also upregulates mRNA for inflammatory mediators in selected brain regions, and pulmonary exposure to SWCNTs upregulates the baroreceptor reflex. In addition, pulmonary exposure to MWCNTs may induce levels of inflammatory mediators in the blood, which may affect the cardiovascular system.

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Section: Workplace Exposures To Cnts or Cnfsmentioning

confidence: 99%

Occupational Nanosafety Considerations for Carbon Nanotubes and Carbon Nanofibers

2012

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“…The metric tonnes which are followed by carbon fibres with a use of 3.9 × 10 4 metric tonnes (Gutiérrez and Bono, 2013). Fibre-reinforced composites often require reworking by machining such as sanding, sawing, grinding or drilling to obtain the final product with the process producing dust in the respirable size range (Midtgard and Jelnes, 1991;Bello et al, 2009;Bello et al, 2010;Cena and Peters, 2011). Recently, the development of advanced composites that utilize engineered nanomaterials raised a concern that workers machining nanocomposites are exposed to airborne particulate matter including individual engineered nanoparticles (see e.g., Thostenson et al, 2005;Ging et al, 2014;Kingston et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Exposure Assessment of Particulate Matter from Abrasive Treatment of Carbon and Glass Fibre-Reinforced Epoxy-Composites - Two Case Studies

Jensen

Levin

Koivisto

et al. 2015

Aerosol Air Qual. Res.

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The use of composites is ever increasing due to their important structural and chemical features. The composite component production often involves high energy grinding and sanding processes to which emissions workers are potentially exposed. In this study we investigated the machining of carbon and glass fibre-reinforced epoxy composite materials at two facilities. We measured particle number concentrations and size distributions of the released material in near field and far field during sanding of glass-and carbon fibre-reinforced composites. We assessed the means of reducing exposure during the work by means of different working style, local exhaust ventilation, and enclosing the process area. Machining processes released particles primarily in < 100 nm size range. Without enclosure, process particle concentrations were 3.9 × 10 4 cm -3 in the near field and 1.3 × 10 4 cm -3 in the far field. Therefore workers in the same area may not be aware of being exposed to the process particles and the need of wearing protective outfits. Comparison of workers working style and effect on near field particle concentrations showed that a careless working style increased particle concentrations of 1.1% and 14.1% when comparing with a careful working style. Investigating the effect of the local exhaust ventilation showed that a maximum flow rate caused removal of close to 100% of particles from the working zone. A 28% reduction in the flow rate reduced particle removal efficiency more than 50%. With the enclosure around the process area, the process particle concentrations were 1.7 × 10 6 cm -3 in the near field, while the concentration in the far field was negligible. The enclosure used was shown to provide an average protection factor of more than 100.

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“…Different types of nanomaterials have been studied by other researchers, among which metals and metal oxides (Park et al, 2009;Tsai et al, 2009) and carbonaceous nanomaterials (Yeganeh et al, 2008;Bello et al, 2010;Johnson et al, 2010) are the most-studied.…”

Section: Introductionmentioning

confidence: 99%

“…Ogura studied the release potential of polystyrenebased composites during the grinding process and reported a significant release of nanoparticles which were realized to be dominantly volatile (Ogura et al, 2013). Solid core drilling of two types of advanced CNT hybrid composites were studied by Bello, who found that very small particles (< 5 nm) were generated from thermal degradation of the composite material (Bello et al, 2010). Cena and Peters measured the respirable mass and number concentration of airborne particles generated from sanding of epoxy nanocomposites and concluded that there were no particles in the nano size range released from this activity (Cena and Peters, 2011).…”

Section: Introductionmentioning

confidence: 99%

Are There Generalizable Trends in the Release of Airborne Synthetic Clay Nanoparticles from a Jet Milling Process?

Faghihi

Martin

Clifford

et al. 2015

Aerosol Air Qual. Res.

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Despite recent efforts to assess the release of nanoparticles to the workplace during different nanotechnology activities, the existence of a generalizable trend in the particle release has yet to be identified. This study aimed to characterize the release of synthetic clay nanoparticles from a laboratory-based jet milling process by quantifying the variations arising from primary particle size and surface treatment of the material used, as well as the feed rate of the machine. A broad range of materials were used in this study, and the emitted particles mass (PM 2.5 ) and number concentrations (PNC) were measured at the release source. Analysis of variance, followed by linear mixed-effects modeling, was applied to quantify the variations in PM 2.5 and PNC of the released particles caused by the abovementioned factors. The results confirmed that using materials of different primary sizes and surface treatment affects the release of the particles from the same process by causing statistically-significant variations in PM 2.5 and PNC. The interaction of these two factors should also be taken into account as it resulted in variations in the measured particles release properties. Furthermore, the feed rate of the milling machine was confirmed to be another influencing parameter. Although this research does not identify a specific pattern in the release of synthetic clay nanoparticles from the jet milling process this is generalizable to other similar settings, it emphasizes that each tested case should be handled individually in terms of exposure considerations.

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Characterization of Exposures To Nanoscale Particles and Fibers During Solid Core Drilling of Hybrid Carbon Nanotube Advanced Composites

Cited by 54 publications

References 13 publications

Occupational Nanosafety Considerations for Carbon Nanotubes and Carbon Nanofibers

Occupational Nanosafety Considerations for Carbon Nanotubes and Carbon Nanofibers

Exposure Assessment of Particulate Matter from Abrasive Treatment of Carbon and Glass Fibre-Reinforced Epoxy-Composites - Two Case Studies

Are There Generalizable Trends in the Release of Airborne Synthetic Clay Nanoparticles from a Jet Milling Process?

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