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Patel HJ, Kwon S . Length-dependent effect of single-walled carbon nanotube exposure in a dynamic cell growth environment of human alveolar epithelial cells. J Expo Sci Environ Epidemiol 2013; 23: 101–108.

Hsieh SF, Bello D, Schmidt DF, Pal AK, Rogers EJ . Biological oxidative damage by carbon nanotubes: fingerprint or footprint? Nanotoxicology 2012; 6: 61–76.

Based in Worcester, MA, Absolute Haitian is the exclusive sales and service partner in the US and Canada for Ningbo Haitian Machinery Co., Ltd. based in Ningbo, China. Ningbo Haitian Machinery Co., Ltd. is the world’s largest supplier of plastics injection molding machinery, shipping an average of 43,000 machines each year. Haitian products are sold in more than 130 countries with machine sizes ranging from 44 to 7,425 tons of clamp force.

Fleury D, Bomfim JAS, Vignes A, Girard C, Metz S, Muñoz F et al. Identification of the main exposure scenarios in the production of CNT-polymer nanocomposites by melt-moulding process. Journal of Cleaner Production 2013; 53: 22–36.

Pötschke P, Bhattacharyya AR, Janke A . Carbon nanotube-filled polycarbonate composites produced by melt mixing and their use in blends with polyethylene. Carbon 2004; 42: 965–969.

Rasmussen PE, Avramescu M-L, Jayawardene I, Gardner HD . Detection of carbon nanotubes in indoor workplaces using elemental impurities. Environ Sci Technol 2015; 49: 12888–12896.

Pötschke P, Abdel-Goad M, Alig I, Dudkin S, Lellinger D . Rheological and dielectrical characterization of melt mixed polycarbonate-multiwalled carbon nanotube composites. Polymer 2004; 45: 8863–8870.

NIOSH.. Current Intelligence Bulletin 65: Occupational exposure to carbon nanotubes and nanofibers, DHHS (NIOSH) Publication No. 2013-145. Atlanta, GA: US National Institute for Occupational Safety and Health 2013. Available at: http://www.cdc.gov/niosh/docs/2013-145/pdfs/2013-145.pdf.

Ogura I, Kotake M, Shigeta M, Uejima M, Saito K, Hashimoto N et al. Potential release of carbon nanotubes from their composites during grinding. J Phys Conf Ser 2013; 429: 012049.

Bussy C, Pinault M, Cambedouzou J, Landry MJ, Jegou P, Mayne-L'hermite M et al. Critical role of surface chemical modifications induced by length shortening on multi-walled carbon nanotubes-induced toxicity. Part Fibre Toxicol 2012; 9: 46.

Open house at 116,000-square-foot applications center in Moncks Corner, SC, featured more than 100 electric and servo-hydraulic plastic injection molding systems.

Köhler AR, Som C, Helland A, Gottschalk F . Studying the potential release of carbon nanotubes throughout the application life cycle. Journal of Cleaner Production 2008; 16: 927–937.

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Muller L, Riediker M, Wick P, Mohr M, Gehr P, Rothen-Rutishauser B . Oxidative stress and inflammation response after nanoparticle exposure: differences between human lung cell monocultures and an advanced three-dimensional model of the human epithelial airways. Journal of the Royal Society, Interface/the Royal Society 2010; 7 (Suppl 1): S27–S40.

Methner M, Crawford C, Geraci C . Evaluation of the potential airborne release of carbon nanofibers during the preparation, grinding, and cutting of epoxy-based nanocomposite material. J Occup Environ Hyg 2012; 9: 308–318.

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Zhang J . Impact of recycling on carbon nanotube filled polymers, Doctoral Thesis University of Massachusetts Lowell. 2015.

Schlagenhauf L, Chu B, Buha J, Nueesch F, Wang J . Release of carbon nanotubes from an epoxy-based nanocomposite during an abrasion process. Envion Sci Technol 2012; 46: 7366–7372.

The Haitian Group introduced their Haitian Precision and Haitian Die Casting product lines to US and Canadian markets at the open house. Both business units’ products are now sold in Asia, Europe, Mexico, and South America. Distribution in the US and Canada will be handled by the Absolute Group with full-scale distribution in 2024.

Mars III servo-hydraulic molding machine – MA 6500 / 6300h (730 U.S. tons) running a two-cavity flowerpot mold; cycle time of 18 seconds

Palomaki J, Valimaki E, Sund J, Vippola M, Clausen PA, Jensen KA et al. Long, needle-like carbon nanotubes and asbestos activate the NLRP3 inflammasome through a similar mechanism. ACS Nano 2011; 5: 6861–6870.

Jupiter III servo-hydraulic, two-platen molding machine – JU 5500 / 4630 (618 U.S. tons) running a thick-wall electrical junction box mold

Zeres III electric molding machine – ZE 1500 / 210 III (169 U.S. tons) running a 4-cavity, thin-wall cup mold; cycle time of 10 seconds

Bello D, Wardle B, Yamamoto N, Guzman deVilloria R, Garcia E, Hart A et al. Exposure to nanoscale particles and fibers during machining of hybrid advanced composites containing carbon nanotubes. J Nanopart Res 2009; 11: 231–249.

Absolute Haitian held an open house and luncheon September 28 for customers and industry members at its 116,000-square-foot applications center in Moncks Corner, SC, which opened in 2019. The event gave industry professionals the opportunity to view new technology, product introductions and more than 100 electric and servo-hydraulic stock machines and large-tonnage subassemblies ready for quick delivery.

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Supplementary Information accompanies the paper on the Journal of Exposure Science and Environmental Epidemiology website

Mazzuckelli LF, Methner MM, Birch ME, Evans DE, Ku BK, Crouch K et al. Identification and characterization of potential sources of worker exposure to carbon nanofibers during polymer composite laboratory operations. J Occup Environ Hyg 2007; 4: D125–D130.

This research was supported by the NSF Grants 120329 and 0425826 and in part by a seed grant from the UC Center for Laboratory Safety. We are grateful to Dr. Earl Ada for his assistance with TEM and SEM analysis, and Dr. Rebecca Gore for her advice with statistical analysis. We also would like to sincerely thank Dr. Eileen Birch of NIOSH for her efforts to analyze CNT-PC and airborne samples for their CNT content and Dr. Martin Shafer of the University of Wisconsin for his assistance with the SF-ICP-MS analysis of the airborne dust.

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In this study, the characteristics of airborne particles generated during injection molding and grinding processes of carbon nanotube reinforced polycarbonate composites (CNT-PC) were investigated. Particle number concentration, size distribution, and morphology of particles emitted from the processes were determined using real-time particle sizers and transmission electron microscopy. The air samples near the operator’s breathing zone were collected on filters and analyzed using scanning electron microscope for particle morphology and respirable fiber count. Processing and grinding during recycling of CNT-PC released airborne nanoparticles (NPs) with a geometric mean (GM) particle concentration from 4.7 × 103 to 1.7 × 106 particles/cm3. The ratios of the GM particle concentration measured during the injection molding process with exhaust ventilation relative to background were up to 1.3 (loading), 1.9 (melting), and 1.4 (molding), and 101.4 for grinding process without exhaust ventilation, suggesting substantial NP exposures during these processes. The estimated mass concentration was in the range of 1.6–95.2 μg/m3. Diverse particle morphologies, including NPs, NP agglomerates, particles with embedded or protruding CNTs and fibers, were observed. No free CNTs were found during any of the investigated processes. The breathing zone respirable fiber concentration during the grinding process ranged from non-detectable to 0.13 fiber/cm3. No evidence was found that the emissions were affected by the number of recycling cycles. Institution of exposure controls is recommended during these processes to limit exposures to airborne NPs and CNT-containing fibers.

Attendees heard from industry experts in a series of quick-hitting “Tech Talks” geared towards providing high-value takeaways. Presenters included:

Boonruksa P, Bello D, Zhang J, Isaacs JA, Mead JL, Woskie SR . Characterization of potential exposures to nanoparticles and fibers during manufacturing and recycling of carbon nanotube reinforced polypropylene composites. Ann Occup Hyg 2016; 60: 40–55.

De Volder M, Tawfick S, Baughman R, Hart A . Carbon nanotubes: present and future commercial applications. Science 2013; 339: 535–539.

Pham GT, Park YB, Wang S, Liang Z, Wang B, Zhang C et al. Mechanical and electrical properties of polycarbonate nanotube buckypaper composite sheets. Nanotechnology 2008; 19: 325705.

Pal AK, Hsieh S-F, Khatri M, Isaacs JA, Demokritou P, Gaines P et al. Screening for oxidative damage by engineered nanomaterials: a comparative evaluation of FRAS and DCFH. J Nanopart Res 2014; 16: 2167.

Froggett SJ, Clancy SF, Boverhof DR, Canady RA . A review and perspective of existing research on the release of nanomaterials from solid nanocomposites. Parti Fibre Toxicol 2014; 11: 17.

On display were three operating injection molding machine cells and a static display of the electric Zeres III molding machine equipped with Haitian’s Medical Package introduced at K 2022. Injection molding machine cells in operation included:

Boonruksa, P., Bello, D., Zhang, J. et al. Exposures to nanoparticles and fibers during injection molding and recycling of carbon nanotube reinforced polycarbonate composites. J Expo Sci Environ Epidemiol 27, 379–390 (2017). https://doi.org/10.1038/jes.2016.26

Unwin J, Coldwell MR, Keen C, McAlinden JJ . Airborne emissions of carcinogens and respiratory sensitizers during thermal processing of plastics. Ann Occup Hyg 2013; 57: 399–406.

Warheit DB, Borm PJ, Hennes C, Lademann J . Testing strategies to establish the safety of nanomaterials: conclusions of an ECETOC workshop. Inhal Toxicol 2007; 19: 631–643.

Nowack B, David RM, Fissan H, Morris H, Shatkin JA, Stintz M et al. Potential release scenarios for carbon nanotubes used in composites. Environ Int 2013; 59: 1–11.

Kingston C, Zepp R, Andrady A, Boverhof D, Fehir R, Hawkins D et al. Release characteristics of selected carbon nanotube polymer composites. Carbon 2014; 68: 33–57.

Golanski L, Guiot A, Pras M, Malarde M, Tardif F . Release-ability of nano fillers from different nanomaterials (toward the acceptability of nanoproduct). J Nanopart Res 2012; 14: 1–9.

Sun B, Wang X, Ji Z, Li R, Xia T . NLRP3 inflammasome activation induced by engineered nanomaterials. Small 2013; 9: 1595–1607.

Bello D, Martin J, Santeufemio C, Sun Q, Lee Bunker K, Shafer M et al. Physicochemical and morphological characterisation of nanoparticles from photocopiers: implications for environmental health. Nanotoxicology 2013; 7: 989–1003.

Haitian Die Casting was established in 2016 and has quickly become of the largest suppliers of die-casting machines in the world. Haitian Die Casting offers standard machines sizes from 180 to 4,500 tons and is one of the few suppliers in the world with the manufacturing capability for die casting machines up to 9,000 tons.  On display was an HDC550 with tonnage of 618 tons/560 tonnes.

Bello D, Wardle BL, Zhang J, Yamamoto N, Santeufemio C, Hallock M et al. Characterization of exposures to nanoscale particles and fibers during solid core drilling of hybrid carbon nanotube advanced composites. Int J Occup Environ Health 2010; 16: 434–450.

Haitian Precision was established in 2002 and offers a wide range of CNC machinery including vertical and horizontal machining centers, lathes, and dual-column machining centers. A preview of the new Haitian Precision product line at the open house included a TC25 II CNC lathe and a VMC850 II vertical machining center. Four vertical machining centers are currently in stock in South Carolina.

Ma-Hock L, Treumann S, Strauss V, Brill S, Luizi F, Mertler M et al. Inhalation toxicity of multiwall carbon nanotubes in rats exposed for 3 months. Toxicol Sci 2009; 112: 468–481.

Wick P, Manser P, Limbach LK, Dettlaff-Weglikowska U, Krumeich F, Roth S et al. The degree and kind of agglomeration affect carbon nanotube cytotoxicity. Toxicol Lett 2007; 168: 121–131.

Journal of Exposure Science & Environmental Epidemiology (J Expo Sci Environ Epidemiol) ISSN 1559-064X (online) ISSN 1559-0631 (print)