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Acid Free Oxidation and Simple Dispersion Method of MWCNT for High-Performance CFRP. NANOMATERIALS 2018; 8:nano8110912. [PMID: 30404184 PMCID: PMC6266042 DOI: 10.3390/nano8110912] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Revised: 10/30/2018] [Accepted: 11/01/2018] [Indexed: 11/19/2022]
Abstract
Carbon nanotubes (CNT) provide an outstanding property spectrum which can be used to improve a wide range of materials. However, the transfer of properties from the nanoscale to a macroscopic material is a limiting factor. Different approaches of functionalizing the surface of a CNT can improve the interaction with the surrounding matrix but is connected to difficult and expensive treatments, which are usually inconvenient for industrial applications. Here, a simple and eco-friendly method is presented for the oxidation of CNT, where hydrogen peroxide (H2O2) is the only chemical needed and no toxic emissions are released. Also, the extensive step of the incorporation of CNT to an epoxy matrix is simplified to an ultrasonic dispersion in the liquid hardener component. The effectiveness is proven by mechanical tests of produced CNT/CFRP and compared to a conventional processing route. The combination of those simple and cost efficient strategies can be utilized to produce multiscale composites with improved mechanical performance in an ecological and economical way.
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Carbon-Based Nanomaterials in Biomass-Based Fuel-Fed Fuel Cells. SENSORS 2017; 17:s17112587. [PMID: 29125564 PMCID: PMC5713132 DOI: 10.3390/s17112587] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 11/05/2017] [Accepted: 11/07/2017] [Indexed: 12/15/2022]
Abstract
Environmental and sustainable economical concerns are generating a growing interest in biofuels predominantly produced from biomass. It would be ideal if an energy conversion device could directly extract energy from a sustainable energy resource such as biomass. Unfortunately, up to now, such a direct conversion device produces insufficient power to meet the demand of practical applications. To realize the future of biofuel-fed fuel cells as a green energy conversion device, efforts have been devoted to the development of carbon-based nanomaterials with tunable electronic and surface characteristics to act as efficient metal-free electrocatalysts and/or as supporting matrix for metal-based electrocatalysts. We present here a mini review on the recent advances in carbon-based catalysts for each type of biofuel-fed/biofuel cells that directly/indirectly extract energy from biomass resources, and discuss the challenges and perspectives in this developing field.
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Hamilton RF, Tsuruoka S, Wu N, Wolfarth M, Porter DW, Bunderson-Schelvan M, Holian A. Length, but Not Reactive Edges, of Cup-stack MWCNT Is Responsible for Toxicity and Acute Lung Inflammation. Toxicol Pathol 2017; 46:62-74. [PMID: 28946794 DOI: 10.1177/0192623317732303] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Multiwalled carbon nanotube (MWCNT) toxicity after inhalation has been associated with size, aspect ratio, rigidity, surface modification, and reactive oxygen species production. In this study, we investigated a series of cup-stacked MWCNT prepared as variants of the Creos 24PS. Mechanical chopping produced a short version (AR10) and graphitization to remove active reaction sites by extreme heat (2,800°C; Creos 24HT) to test the contribution of length and alteration of potential reaction sites to toxicity. The 3 MWCNT variants were tested in vitro in a human macrophage-like cell model and with C57BL/6 alveolar macrophages for dose-dependent toxicity and NLRP3 inflammasome activation. The 24PS and 24HT variants showed significant dose-dependent toxicity and inflammasome activation. In contrast, the AR10 variant showed no toxicity or bioactivity at any concentration tested. The in vivo results reflected those observed in vitro, with the 24PS and 24HT variants resulting in acute inflammation, including elevated polymorphonuclear counts, Interleukin (IL)-18, cathepsin B, and lactate dehydrogenase in isolated lung lavage fluid from mice exposed to 40 µg MWCNT. Taken together, these data indicate that length, but not the absence of proposed reaction sites, on the MWCNT influences particle bioactivity.
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Affiliation(s)
- Raymond F Hamilton
- 1 Department of Biomedical and Pharmaceutical Sciences, Center for Environmental Health Sciences, University of Montana, Missoula, Montana, USA
| | - Shuji Tsuruoka
- 2 Institute of Carbon Science and Technology, Shinshu University, Nagano, Japan
| | - Nianqiang Wu
- 3 Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, West Virginia, USA
| | - Michael Wolfarth
- 4 National Institute for Occupational Safety and Health, Morgantown, West Virginia, USA
| | - Dale W Porter
- 4 National Institute for Occupational Safety and Health, Morgantown, West Virginia, USA
| | - Melisa Bunderson-Schelvan
- 1 Department of Biomedical and Pharmaceutical Sciences, Center for Environmental Health Sciences, University of Montana, Missoula, Montana, USA
| | - Andrij Holian
- 1 Department of Biomedical and Pharmaceutical Sciences, Center for Environmental Health Sciences, University of Montana, Missoula, Montana, USA
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Stueckle TA, Davidson DC, Derk R, Wang P, Friend S, Schwegler-Berry D, Zheng P, Wu N, Castranova V, Rojanasakul Y, Wang L. Effect of surface functionalizations of multi-walled carbon nanotubes on neoplastic transformation potential in primary human lung epithelial cells. Nanotoxicology 2017; 11:613-624. [PMID: 28513319 DOI: 10.1080/17435390.2017.1332253] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Functionalized multi-walled carbon nanotube (fMWCNT) development has been intensified to improve their surface activity for numerous applications, and potentially reduce toxic effects. Although MWCNT exposures are associated with lung tumorigenesis in vivo, adverse responses associated with exposure to different fMWCNTs in human lung epithelium are presently unknown. This study hypothesized that different plasma-coating functional groups determine MWCNT neoplastic transformation potential. Using our established model, human primary small airway epithelial cells (pSAECs) were continuously exposed for 8 and 12 weeks at 0.06 μg/cm2 to three-month aged as-prepared-(pMWCNT), carboxylated-(MW-COOH), and aminated-MWCNTs (MW-NHx). Ultrafine carbon black (UFCB) and crocidolite asbestos (ASB) served as particle controls. fMWCNTs were characterized during storage, and exposed cells were assessed for several established cancer cell hallmarks. Characterization analyses conducted at 0 and 2 months of aging detected a loss of surface functional groups over time due to atmospheric oxidation, with MW-NHx possessing less oxygen and greater lung surfactant binding affinity. Following 8 weeks of exposure, all fMWCNT-exposed cells exhibited significant increased proliferation compared to controls at 7 d post-treatment, while UFCB- and ASB-exposed cells did not differ significantly from controls. UFCB, pMWCNT, and MW-COOH exposure stimulated significant transient invasion behavior. Conversely, aged MW-NHx-exposed cells displayed moderate increases in soft agar colony formation and morphological transformation potential, while UFCB cells showed a minimal effect compared to all other treatments. In summary, surface properties of aged fMWCNTs can impact cell transformation events in vitro following continuous, occupationally relevant exposures.
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Affiliation(s)
- Todd A Stueckle
- a Health Effects Laboratory Division , National Institute for Occupational Safety and Health , Morgantown , WV , USA
| | - Donna C Davidson
- a Health Effects Laboratory Division , National Institute for Occupational Safety and Health , Morgantown , WV , USA
| | - Ray Derk
- a Health Effects Laboratory Division , National Institute for Occupational Safety and Health , Morgantown , WV , USA
| | - Peng Wang
- b Department of Pharmaceutical Sciences, School of Pharmacy , West Virginia University , Morgantown , WV , USA
| | - Sherri Friend
- a Health Effects Laboratory Division , National Institute for Occupational Safety and Health , Morgantown , WV , USA
| | - Diane Schwegler-Berry
- a Health Effects Laboratory Division , National Institute for Occupational Safety and Health , Morgantown , WV , USA
| | - Peng Zheng
- c Department of Mechanical and Aerospace Engineering , West Virginia University , Morgantown , WV , USA
| | - Nianqiang Wu
- c Department of Mechanical and Aerospace Engineering , West Virginia University , Morgantown , WV , USA
| | - Vince Castranova
- b Department of Pharmaceutical Sciences, School of Pharmacy , West Virginia University , Morgantown , WV , USA
| | - Yon Rojanasakul
- b Department of Pharmaceutical Sciences, School of Pharmacy , West Virginia University , Morgantown , WV , USA
| | - Liying Wang
- a Health Effects Laboratory Division , National Institute for Occupational Safety and Health , Morgantown , WV , USA
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Watson-Wright C, Singh D, Demokritou P. Toxicological Implications of Released Particulate Matter during Thermal Decomposition of Nano-Enabled Thermoplastics. NANOIMPACT 2017; 5:29-40. [PMID: 29333505 PMCID: PMC5764161 DOI: 10.1016/j.impact.2016.12.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Nano-enabled thermoplastics are part of the growing market of nano-enabled products (NEPs) that have vast utility in several industries and consumer goods. The use and disposal of NEPs at their end of life has raised concerns about the potential release of constituent engineered nanomaterials (ENMs) during thermal decomposition and their impact on environmental health and safety. To investigate this issue, industrially relevant nano-enabled thermoplastics including polyurethane, polycarbonate, and polypropylene containing carbon nanotubes (0.1 and 3% w/v, respectively), polyethylene containing nanoscale iron oxide (5% w/v), and ethylene vinyl acetate containing nanoscale titania (2 and 5% w/v) along with their pure thermoplastic matrices were thermally decomposed using the recently developed lab based Integrated Exposure Generation System (INEXS). The life cycle released particulate matter (called LCPM) was monitored using real time instrumentation, size fractionated, sampled, extracted and prepared for toxicological analysis using primary small airway epithelial cells to assess potential toxicological effects. Various cellular assays were used to assess reactive oxygen species and total glutathione as measurements of oxidative stress along with mitochondrial function, cellular viability, and DNA damage. By comparing toxicological profiles of LCPM released from polymer only (control) with nano-enabled LCPM, potential nanofiller effects due to the use of ENMs were determined. We observed associations between NEP properties such as the percent nanofiller loading, host matrix, and nanofiller chemical composition and the physico-chemical properties of released LCPM, which were linked to biological outcomes. More specifically, an increase in percent nanofiller loading promoted a toxicological response independent of increasing LCPM dose. Importantly, differences in host matrix and nanofiller composition were shown to enhance biological activity and toxicity of LCPM. This work highlights the importance of assessing the toxicological properties of LCPM and raises environmental health and safety concerns of nano-enabled products at their end of life during thermal decomposition/incineration.
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Affiliation(s)
| | | | - Philip Demokritou
- To whom correspondence should be addressed: Prof. Philip Demokritou, Associate Professor, Department of Environmental Health, Harvard T.H. Chan School of Public, Health, 677 Huntington Avenue, Boston, MA 02115, USA, , Tel: 617-432-3481
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