Title:
Safety Risks Associated with Carbon Nanotube-Reinforced Mortar
Author(s):
Hugh D. Miller, Sara Mesgari, Ali Akbarnezhad, and Stephen Foster
Publication:
Materials Journal
Volume:
114
Issue:
6
Appears on pages(s):
897-909
Keywords:
carbon nanotubes; fiber reinforcement; mortar
DOI:
10.14359/51700892
Date:
11/1/2017
Abstract:
Carbon nanotube (CNT) reinforcement has been reported to improve mechanical properties and durability of concrete. However, numerous health concerns have been attributed to CNTs, forming a major barrier to their widespread use. Human exposure to CNTs is considered unlikely while CNTs are dispersed in liquid or embedded in a concrete matrix. However, respirable CNT-contaminated particles, including free CNTs and CNTs attached to hydrated cement products, may be released during production, processing, or demolition of CNT-reinforced concrete. In this paper, the risk of presence of respirable CNT-contaminated particles in the wastewater generated during mixing and dusts generated during crushing of CNT-reinforced mortar is investigated by varying the type (singlewalled and multi-walled CNTs), concentration, and dispersion method of CNTs. A considerably lower risk of presence of CNTs in respirable particles generated during mortar production and demolition is found for multi-walled CNTs versus single-walled CNTs. Furthermore, functionalization of CNTs is identified as an effective method to reduce the health and safety risks associated with mixing and demolition of the CNT-reinforced cementitious materials. The presence of CNTs in the respirable particles generated is found to increase with an increase in concentration of CNTs.
Related References:
1. Baughman, R. H.; Zakhidov, A. A.; and de Heer, W. A., “Carbon Nanotubes—The Route Toward Applications,” Science, V. 297, No. 5582, 2002, pp. 787-792. doi: 10.1126/science.1060928
2. Chen, S. J.; Collins, F. G.; Macleod, A. J. N.; Pan, Z.; Duan, W. H.; and Wang, C. M., “Carbon Nanotube-Cement Composites: A Retrospect,” The IES Journal Part A: Civil & Structural Engineering, V. 4, No. 4, 2011, pp. 254-268.
3. Siddique, R., and Mehta, A., “Effect of Carbon Nanotubes on Properties of Cement Mortars,” Construction and Building Materials, V. 50, 2014, pp. 116-129. doi: 10.1016/j.conbuildmat.2013.09.019
4. Yu, M. F.; Lourie, O.; Dyer, M. J.; Moloni, K.; Kelly, T. F.; and Ruoff, R. S., “Strength and Breaking Mechanism of Multiwalled Carbon Nanotubes under Tensile Load,” Science, V. 287, No. 5453, 2000, pp. 637-640. doi: 10.1126/science.287.5453.637
5. Wang, M. S.; Golberg, D.; and Bando, Y., “Tensile Tests on Individual Single-Walled Carbon Nanotubes: Linking Nanotube Strength with Its Defects,” Advanced Materials, V. 22, No. 36, 2010, pp. 4071-4075. doi: 10.1002/adma.201001463
6. Lu, J. P., “Elastic Properties of Carbon Nanotubes and Nanoropes,” Physical Review Letters, V. 79, No. 7, 1997, pp. 1297-1300. doi: 10.1103/PhysRevLett.79.1297
7. Yu, M. F.; Files, B. S.; Arepalli, S.; and Ruoff, R. S., “Tensile Loading of Ropes of Single Wall Carbon Nanotubes and Their Mechanical Properties,” Physical Review Letters, V. 84, No. 24, 2000, pp. 5552-5555. doi: 10.1103/PhysRevLett.84.5552
8. Chan, L. Y., and Andrawes, B., “Finite Element Analysis of Carbon Nanotube/Cement Composite with Degraded Bond Strength,” Computational Materials Science, V. 47, No. 4, 2010, pp. 994-1004. doi: 10.1016/j.commatsci.2009.11.035
9. Campillo, I.; Dolado, J. S.; and Porro, A., High-Performance Nanostructured Materials for Construction, in Nanotechnology in Construction, Royal Society of Chemistry, London, UK, 2004.
10. Li, G. Y.; Wang, P. M.; and Zhao, X. H., “Mechanical Behavior and Microstructure of Cement Composites Incorporating Surface-Treated Multi-Walled Carbon Nanotubes,” Carbon, V. 43, No. 6, 2005, pp. 1239-1245. doi: 10.1016/j.carbon.2004.12.017
11. Cwirzen, A.; Habermehl-Cwirzen, K.; and Penttala, V., “Surface Decoration of Carbon Nanotubes and Mechanical Properties of Cement/Carbon Nanotube Composites,” Advances in Cement Research, V. 20, No. 2, 2008, pp. 65-73. doi: 10.1680/adcr.2008.20.2.65
12. Konsta-Gdoutos, M. S.; Metaxa, Z. S.; and Shah, S. P., “Multi-Scale Mechanical and Fracture Characteristics and Early-Age Strain Capacity of High Performance Carbon Nanotube/Cement Nanocomposites,” Cement and Concrete Composites, V. 32, No. 2, 2010, pp. 110-115. doi: 10.1016/j.cemconcomp.2009.10.007
13. Musso, S.; Tulliani, J. M.; Ferro, G.; and Tagliaferro, A., “Influence of Carbon Nanotubes Structure on the Mechanical Behavior of Cement Composites,” Composites Science and Technology, V. 69, No. 11-12, 2009, pp. 1985-1990. doi: 10.1016/j.compscitech.2009.05.002
14. Melo, V. S.; Calixto, J. M. F.; Ladeira, L. O.; and Silva, A. P., “Macro- and Micro-Characterization of Mortars Produced with Carbon Nanotubes,” ACI Materials Journal, V. 108, No. 3, May-June 2011, pp. 327-332.
15. Metaxa, Z. S.; Seo, J. W. T.; Konsta-Gdoutos, M. S.; Hersam, M. C.; and Shah, S. P., “Highly Concentrated Carbon Nanotube Admixture for Nano-fiber Reinforced Cementitious Materials,” Cement and Concrete Composites, V. 34, No. 5, 2012, pp. 612-617. doi: 10.1016/j.cemconcomp.2012.01.006
16. Konsta-Gdoutos, M. S.; Metaxa, Z. S.; and Shah, S. P., “Highly Dispersed Carbon Nanotube Reinforced Cement Based Materials,” Cement and Concrete Research, V. 40, No. 7, 2010, pp. 1052-1059. doi: 10.1016/j.cemconres.2010.02.015
17. Abu Al-Rub, R. K.; Ashour, A. I.; and Tyson, B. M., “On the Aspect Ratio Effect of Multi-Walled Carbon Nanotube Reinforcements on the Mechanical Properties of Cementitious Nanocomposites,” Construction and Building Materials, V. 35, 2012, pp. 647-655. doi: 10.1016/j.conbuildmat.2012.04.086
18. Collins, F.; Lambert, J.; and Duan, W. H., “The Influences of Admixtures on the Dispersion, Workability, and Strength of Carbon Nanotube-OPC Paste Mixtures,” Cement and Concrete Composites, V. 34, No. 2, 2012, pp. 201-207. doi: 10.1016/j.cemconcomp.2011.09.013
19. Sobolkina, A.; Mechtcherine, V.; Khavrus, V.; Maier, D.; Mende, M.; Ritschel, M.; and Leonhardt, A., “Dispersion of Carbon Nanotubes and its Influence on the Mechanical Properties of the Cement Matrix,” Cement and Concrete Composites, V. 34, No. 10, 2012, pp. 1104-1113. doi: 10.1016/j.cemconcomp.2012.07.008
20. Nasibulina, L. I.; Anoshkin, I. V.; Nasibulin, A. G.; Cwirzen, A.; Penttala, V.; and Kauppinen, E. I., “Effect of Carbon Nanotube Aqueous Dispersion Quality on Mechanical Properties of Cement Composite,” Journal of Nanomaterials, V. 2012, 2012, pp. 1-6. doi: 10.1155/2012/169262
21. Kumar, S.; Kolay, P.; Malla, S.; and Mishra, S., “Effect of Multiwalled Carbon Nanotubes on Mechanical Strength of Cement Paste,” Journal of Materials in Civil Engineering, ASCE, V. 24, No. 1, 2012, pp. 84-91. doi: 10.1061/(ASCE)MT.1943-5533.0000350
22. Metaxa, Z. S.; Konsta-Gdoutos, M. S.; and Shah, S. P., “Carbon Nanofiber Cementitious Composites: Effect of Debulking Procedure on Dispersion and Reinforcing Efficiency,” Cement and Concrete Composites, V. 36, 2013, pp. 25-32. doi: 10.1016/j.cemconcomp.2012.10.009
23. Wang, B. M.; Han, Y.; and Liu, S., “Effect of Highly Dispersed Carbon Nanotubes on the Flexural Toughness of Cement-Based Composites,” Construction and Building Materials, V. 46, 2013, pp. 8-12. doi: 10.1016/j.conbuildmat.2013.04.014
24. Sanchez, F., and Ince, C., “Microstructure and Macroscopic Properties of Hybrid Carbon Nanofiber/Silica Fume Cement Composites,” Composites Science and Technology, V. 69, No. 7-8, 2009, pp. 1310-1318. doi: 10.1016/j.compscitech.2009.03.006
25. Chaipanich, A.; Nochaiya, T.; Wongkeo, W.; and Torkittikul, P., “Compressive Strength and Microstructure of Carbon Nanotubes—Fly Ash Cement Composites,” Materials Science and Engineering A, V. 527, No. 4-5, 2010, pp. 1063-1067. doi: 10.1016/j.msea.2009.09.039
26. Nochaiya, T., and Chaipanich, A., “Behavior of Multi-Walled Carbon Nanotubes on the Porosity and Microstructure of Cement-Based Materials,” Applied Surface Science, V. 257, No. 6, 2011, pp. 1941-1945. doi: 10.1016/j.apsusc.2010.09.030
27. Morsy, M. S.; Alsayed, S. H.; and Aqel, M., “Hybrid Effect of Carbon Nanotube and Nano-clay on Physico-mechanical Properties of Cement Mortar,” Construction and Building Materials, V. 25, No. 1, 2011, pp. 145-149. doi: 10.1016/j.conbuildmat.2010.06.046
28. Hunashyal, A. M.; Lohitha, S. J.; Quadri, S. S.; and Banapurmath, N. R., “Experimental Investigation of the Effect of Carbon Nanotubes and Carbon Fibres on the Behaviour of Plain Cement Composite Beams,” The IES Journal Part A: Civil & Structural Engineering, V. 4, No. 1, 2011, pp. 29-36.
29. Peyvandi, A.; Sbia, L. A.; Soroushian, P.; and Sobolev, K., “Effect of the Cementitious Paste Density on the Performance Efficiency of Carbon Nanofiber in Concrete Nanocomposite,” Construction and Building Materials, V. 48, 2013, pp. 265-269. doi: 10.1016/j.conbuildmat.2013.06.094
30. Kim, H. K.; Nam, I. W.; and Lee, H. K., “Enhanced Effect of Carbon Nanotube on Mechanical and Electrical Properties of Cement Composites by Incorporation of Silica Fume,” Composite Structures, V. 107, 2014, pp. 60-69. doi: 10.1016/j.compstruct.2013.07.042
31. Makar, J., The Effect of SWCNT and Other Nanomaterials on Cement Hydration and Reinforcement in Nanotechnology in Civil Infrastructure, Springer, 2011.
32. Chuah, S.; Pan, Z.; Sanjayan, J. G.; Wang, C. M.; and Duan, W. H., “Nano Reinforced Cement and Concrete Composites and New Perspective from Graphene Oxide,” Construction and Building Materials, V. 73, 2014, pp. 113-124. doi: 10.1016/j.conbuildmat.2014.09.040
33. Raki, L.; Beaudoin, J.; Alizadeh, R.; Makar, J.; and Sato, T., “Cement and Concrete Nanoscience and Nanotechnology,” Materials (Basel), V. 3, No. 2, 2010, pp. 918-942. doi: 10.3390/ma3020918
34. Bandyopadhyaya, R.; Nativ-Roth, E.; Regev, O.; and Yerushalmi-Rozen, R., “Stabilization of Individual Carbon Nanotubes in Aqueous Solutions,” Nano Letters, V. 2, No. 1, 2002, pp. 25-28. doi: 10.1021/nl010065f
35. Yan, L. Y.; Li, W. F.; Mesgari, S.; Leong, S. S. J.; Chen, Y.; Loo, L. S.; Mu, Y. G.; and Chan-Park, M. B., “Use of a Chondroitin Sulfate Isomer as an Effective and Removable Dispersant of Single-Walled Carbon Nanotubes,” Small, V. 7, No. 19, 2011, pp. 2758-2768. doi: 10.1002/smll.201100708
36. Arena, U.; Mastellone, M. L.; Camino, G.; and Boccaleri, E., “An Innovative Process for Mass Production of Multi-Wall Carbon Nanotubes by Means of Low-Cost Pyrolysis of Polyolefins,” Polymer Degradation & Stability, V. 91, No. 4, 2006, pp. 763-768. doi: 10.1016/j.polymdegradstab.2005.05.029
37. Jia, G.; Wang, H. F.; Yan, I.; Wang, X.; Pei, R. J.; Yan, T.; Zhao, Y. L.; and Guo, X. B., “Cytotoxicity of Carbon Nanomaterials: Single-Wall Nanotube, Multi-Wall Nanotube, and Fullerene,” Environmental Science & Technology, V. 39, No. 5, 2005, pp. 1378-1383. doi: 10.1021/es048729l
38. Park, E.-J.; Kim, H.; Kim, Y.; Yi, J.; Choi, K.; and Park, K., “Carbon Fullerenes (C60s) Can Induce Inflammatory Responses in the Lung of Mice,” Toxicology and Applied Pharmacology, V. 244, No. 2, 2010, pp. 226-233. doi: 10.1016/j.taap.2009.12.036
39. Lam, C.; James, J. T.; McCluskey, R.; Arepalli, S.; and Hunter, R. L., “A Review of Carbon Nanotube Toxicity and Assessment of Potential Occupational and Environmental Health Risks,” Critical Reviews in Toxicology, V. 36, No. 3, 2006, pp. 189-217. doi: 10.1080/10408440600570233
40. Kang, S.; Herzberg, M.; Rodrigues, D. F.; and Elimelech, M., “Antibacterial Effects of Carbon Nanotubes: Size Does Matter,” Langmuir, V. 24, No. 13, 2008, pp. 6409-6413. doi: 10.1021/la800951v
41. Kang, S.; Mauter, M. S.; and Elimelech, M., “Physicochemical Determinants of Multiwalled Carbon Nanotube Bacterial Cytotoxicity,” Environmental Science & Technology, V. 42, No. 19, 2008, pp. 7528-7534. doi: 10.1021/es8010173
42. Kang, S.; Mauter, M. S.; and Elimelech, M., “Microbial Cytotoxicity of Carbon-Based Nanomaterials: Implications for River Water and Wastewater Effluent,” Environmental Science & Technology, V. 43, No. 7, 2009, pp. 2648-2653. doi: 10.1021/es8031506
43. Kang, S.; Pinault, M.; Pfefferle, L. D.; and Elimelech, M., “Single-Walled Carbon Nanotubes Exhibit Strong Antimicrobial Activity,” Langmuir, V. 23, No. 17, 2007, pp. 8670-8673. doi: 10.1021/la701067r
44. Shvedova, A. A.; Kisin, E. R.; Mercer, R.; Murray, A. R.; Johnson, V. J.; Potapovich, A. I.; Tyurina, Y. Y.; Gorelik, O.; Arepalli, S.; Schwegler-Berry, D.; Hubbs, A. F.; Antonini, J.; Evans, D. E.; Ku, B. K.; Ramsey, D.; Maynard, A.; Kagan, V. E.; and Castranova, V., “Unusual Inflammatory and Fibrogenic Pulmonary Responses to Single-Walled Carbon Nanotubes in Mice,” American Journal of Physiology. Lung Cellular and Molecular Physiology, V. 289, No. 5, 2005, pp. L698-L708. doi: 10.1152/ajplung.00084.2005
45. Muller, J.; Huaux, F.; Moreau, N.; Misson, P.; Heilier, J. F.; Delos, M.; Arras, M.; Fonseca, A.; Nagy, J. B.; and Lison, D., “Respiratory Toxicity of Multi-Wall Carbon Nanotubes,” Toxicology and Applied Pharmacology, V. 207, No. 3, 2005, pp. 221-231. doi: 10.1016/j.taap.2005.01.008
46. Ding, L.; Stilwell, J.; Zhang, T.; Elboudwarej, O.; Jiang, H.; Selegue, J. P.; Cooke, P. A.; Gray, J. W.; and Chen, F. F., “Molecular Characterization of the Cytotoxic Mechanism of Multiwall Carbon Nanotubes and Nano-Onions on Human Skin Fibroblast,” Nano Letters, V. 5, No. 12, 2005, pp. 2448-2464. doi: 10.1021/nl051748o
47. Wei, W.; Sethuraman, A.; Jin, C.; Monteiro-Riviere, N. A.; and Narayan, R. J., “Biological Properties of Carbon Nanotubes,” Journal of Nanoscience and Nanotechnology, V. 7, No. 4, 2007, pp. 1284-1297. doi: 10.1166/jnn.2007.655
48. Basak, G. C.; Kumar, K. D.; Bandyopadhyay, A.; and Bhowmick, A. K., “Elegant Way of Strengthening Polymer: Polymer Interface Using Nanoclay,” ACS Applied Materials & Interfaces, V. 2, No. 10, 2010, pp. 2933-2943. doi: 10.1021/am100865n
49. Demo, M.; Jentsch, W.; and Hoffmann, L., “Effect of Long Time Exposure to Different Environmental Temperatures on Heat Production of Growing Pigs,” Livestock Production Science, V. 43, No. 2, 1995, pp. 149-152. doi: 10.1016/0301-6226(95)00035-J
50. Hoffmann, M. R.; Martin, S. T.; Choi, W.; and Bahnemann, D. W., “Environmental Applications of Semiconductor Photocatalysis,” Chemical Reviews, V. 95, No. 1, 1995, pp. 69-96. doi: 10.1021/cr00033a004
51. Hansen, S. F.; Michelson, E. S.; Kamper, A.; Borling, P.; Stuer-Lauridsen, F.; and Baun, A., “Categorization Framework to Aid Exposure Assessment of Nanomaterials in Consumer Products,” Ecotoxicology (London, England), V. 17, No. 5, 2008, pp. 438-447. doi: 10.1007/s10646-008-0210-4
52. Safe Work Australia, Safe Handling and Use of Carbon Nanotubes, IT and Knowledge Management, 2012, 3 pp.
53. Buzea, C.; Pacheco, I. I.; and Robbie, K., “Nanomaterials and Nanoparticles: Sources and Toxicity,” Biointerphases, V. 2, No. 4, 2007, pp. MR17-MR71. doi: 10.1116/1.2815690
54. Horie, M.; Komaba, L. K.; Fukui, H.; Kato, H.; Endoh, S.; Nakamura, A.; Miyauchi, A.; Maru, J.; Miyako, E.; Fujita, K.; Hagihara, Y.; Yoshida, Y.; and Iwahashi, H., “Evaluation of the Biological Influence of a Stable Carbon Nanohorn Dispersion,” Carbon, V. 54, 2013, pp. 155-167. doi: 10.1016/j.carbon.2012.11.015
55. Soto, K. F.; Garza, K. M.; Shi, Y.; and Murr, L. E., “Direct Contact Cytotoxicity Assays for Filter-Collected, Carbonaceous (Soot) Nanoparticulate Material and Observations of Lung Cell Response,” Atmospheric Environment, V. 42, No. 9, 2008, pp. 1970-1982. doi: 10.1016/j.atmosenv.2007.12.027
56. Herzog, E.; Byrne, H. J.; Casey, A.; Davoren, M.; Lenz, A. G.; Maier, K. L.; Duschl, A.; and Oostingh, G. J., “SWCNT Suppress Inflammatory Mediator Responses in Human Lung Epithelium in Vitro,” Toxicology and Applied Pharmacology, V. 234, No. 3, 2009, pp. 378-390. doi: 10.1016/j.taap.2008.10.015
57. NIOSH, “Occupational Exposure to Carbon Nanotubes and Nanofibers,” Current Intelligence Bulletin 65, 2013.
58. Hinkley, G. J., and Roberts, S. M., “Particle and Fiber Toxicology,” Particulate Products: Tailoring Properties for Optimal Performance, Springer International Publishing Switzerland, 2014, pp. 153-165.
59. WHO/SDE/OEH/99.14R., “Hazard Prevention and Control in the Work Environment: Airborne Dust,” Protection of the Human Environment Occupational Health and Environmental Health Series, World Health Organization, Geneva, Switzerland, 1999.
60. Safe Work Australia, Guidance on the Interpretation of Workplace Exposure Standards for Airborne Contaminants, 2013, 40 pp.
61. Köhler, A. R.; Som, C.; Helland, A.; and Gottschalk, F., “Studying the Potential Release of Carbon Nanotubes throughout the Application Life Cycle,” Journal of Cleaner Production, V. 16, No. 8-9, 2008, pp. 927-937. doi: 10.1016/j.jclepro.2007.04.007
62. Read, S. A. K.; Jiménez, A. S.; Ross, B. L.; Aitken, R. J.; and van Tongeren, M., “Nanotechnology and Exposure Scenarios,” Handbook of Nanosafety, U. Vogel et al., eds., Academic Press, San Diego, CA, Chapter 2, 2014, pp. 17-58.
63. Mesgari, S.; Coulombe, S.; Hordy, N.; and Taylor, R. A., “Thermal Stability of Carbon Nanotube-Based Nanofluids for Solar Thermal Collectors,” Materials Research Innovations, V. 19, 2015, pp. 650-653. doi: 10.1179/1432891714Z.0000000001169
64. Mesgari, S.; Sundramoorthy, A. K.; Loo, L. S.; and Chan-Park, M. B., “Gel Electrophoresis Using a Selective Radical for the Separation of Single-Walled Carbon Nanotubes,” Faraday Discussions, V. 173, 2014, pp. 351-363. doi: 10.1039/C4FD00092G
65. Sundramoorthy, A. K.; Mesgari, S.; Wang, J.; Kumar, R.; Sk, M. A.; Yeap, S. H.; Zhang, Q.; Sze, S. K.; Lim, K. H.; and Chan-Park, M. B., “Scalable and Effective Enrichment of Semiconducting Single-Walled Carbon Nanotubes by a Dual Selective Naphthalene-Based Azo Dispersant,” Journal of the American Chemical Society, V. 135, No. 15, 2013, pp. 5569-5581. doi: 10.1021/ja312282g
66. Sun, Y. P.; Fu, K. F.; Lin, Y.; and Huang, W. J., “Functionalized Carbon Nanotubes: Properties and Applications,” Accounts of Chemical Research, V. 35, No. 12, 2002, pp. 1096-1104. doi: 10.1021/ar010160v
67. Mesgari, S.; Taylor, R. A.; Hjerrild, N. E.; Crisostomo, F.; Li, Q. Y.; and Scott, J., “An Investigation of Thermal Stability of Carbon Nanofluids for Solar Thermal Applications,” Solar Energy Materials and Solar Cells, V. 157, 2016, pp. 652-659. doi: 10.1016/j.solmat.2016.07.032
68. Duan, W. H.; Wang, Q.; and Collins, F., “Dispersion of Carbon Nanotubes with SDS Surfactants: A Study from a Binding Energy Perspective,” Chemical Science (Cambridge), V. 2, No. 7, 2011, pp. 1407-1413. doi: 10.1039/c0sc00616e
69. Du, M. R.; Jing, H. W.; Duan, W. H.; Han, G. S.; and Chen, S. J., “Methylcellulose Stabilized Multi-Walled Carbon Nanotubes Dispersion for Sustainable Cement Composites,” Construction and Building Materials, V. 146, 2017, pp. 76-85. doi: 10.1016/j.conbuildmat.2017.04.029
70. Chen, S. J.; Wang, W.; Sagoe-Crentsil, K.; Collins, F.; Zhao, X. L.; Majumder, M.; and Duan, W. H., “Distribution of Carbon Nanotubes in Fresh Ordinary Portland Cement Pastes: Understanding from a Two-Phase Perspective,” RSC Advances, V. 6, No. 7, 2016, pp. 5745-5753. doi: 10.1039/C5RA13511G
71. Hordy, N.; Rabilloud, D.; Meunier, J.-L.; and Coulombe, S., “High Temperature and Long-Term Stability of Carbon Nanotube Nanofluids for Direct Absorption Solar Thermal Collectors,” Solar Energy, V. 105, 2014, pp. 82-90. doi: 10.1016/j.solener.2014.03.013
72. Tamura, M.; Inada, M.; Nakazato, T.; Yamamoto, K.; Endo, S.; Uchida, K.; Horie, M.; Fukui, H.; Iwahashi, H.; Kobayashi, N.; Morimoto, Y.; and Tao, H., “A Determination Method of Pristine Multiwall Carbon Nanotubes in Rat Lungs after Intratracheal Instillation Exposure by Combustive Oxidation-Nondispersive Infrared Analysis,” Talanta, V. 84, No. 3, 2011, pp. 802-808. doi: 10.1016/j.talanta.2011.02.017
73. Wepasnick, K. A.; Smith, B. A.; Bitter, J. L.; and Fairbrother, D. H., “Chemical and Structural Characterization of Carbon Nanotube Surfaces,” Analytical and Bioanalytical Chemistry, V. 396, No. 3, 2010, pp. 1003-1014. doi: 10.1007/s00216-009-3332-5
74. Huang, Y. Y., and Terentjev, E. M., “Dispersion of Carbon Nanotubes: Mixing, Sonication, Stabilization, and Composite properties,” Polymers, V. 4, No. 4, 2012, pp. 275-295. doi: 10.3390/polym4010275
75. Jain, R., “Carbon Nanotube Reinforced Polyacrylonitrile and Poly(etherketone) Fibers,” Textile and Fibre Engineering, Georgia Institute of Technology, Atlanta, GA, 2009, 274 pp.