Special features for functionalization of carbon nanotubes nanopowders
DOI:
https://doi.org/10.15407/hftp10.04.367Keywords:
carbon nanotube powders, powder modification, physicochemical characteristicsAbstract
Physical and mechanical properties of carbon nanotube (CNT) powders depend on the method of their synthesis and chemical refinement. In order to create new composite materials that contain CNT powders as a filler, it is necessary to achieve functionalization of powder surface.
Functionalization of MWCNT-A brand CNT powder surface using pulse processing by high voltage electric discharges (HVED) in liquid leads to changes in distribution of its particles by size, a decrease in amorphous carbon content and in powder thermostability. Sedimentation separation of powder after HVED processing leads to formation of powder in three size ranges (0.118–0.139, 2.639–20.895 and 2.44–33.701 µm). Thermochemical modification of CNT powders leads to an increase in specific surface area, total volume of pores and micropores, their mean radii, a decrease in impurities content, changes in distribution of its particles by size, a decrease in amorphous carbon content and in powder thermostability. Electrochemical reconstruction of the surface of specimens of initial MWCNT-A brand CNT powder allows decreasing impurities content, free energy of surface saturation by water vapor, specific magnetic susceptibility, electrokinetic potential as well as increasing specific surface area, pores total volume and hydrogen adsorption.
Consecutive application of these methods leads to a decrease in impurities content in MWCNT-A brand CNT powder and to changes of its physical and chemical characteristics. Mass share of impurities decreases 3.7 times, mass share of soluble impurities decreases 7 times, specific magnetic susceptibility increases 5.2 times, electrokinetic potential increases 7.8 times. Specific electric resistivity increases 1.3 times, which leads to changes of adsorption and structural characteristics of powder: specific surface area increases 1.4 times and free energy of surface saturation by water vapor decreases by 11.9 %, which means that surface becomes more hydrophobic. As a result of such changes, rate of hydrogen adsorption on powders surface increases by 46 % and the current density at the potential of –0.6 V increases by 50 %.
References
1. Vterkovskii M.Ia., Solodkii E.V., Bohomol Yu.I. The effect of the concentration of carbon fibers on the mechanical properties of ceramics based on boron carbide obtained by the method of infiltration. In: Materials science refractory compounds. Proc. 6th Int. Scientific Conf. (22-24 May, 2018, Kyiv). P. 86. [in Russian].
2. Tkachov A.H., Zolotukhin I.V. Equipment and Methods for Synthesis of Solid-State Nanostructures. (Moskow: Mashinostroenie, 2007). [in Russian].
3. Shylo A.E. Composite tool materials. In: Superhard material. Generation and application. V. 6. (Kyiv: ISM, IPC «ALKON» NANU, 2005). [in Russian].
4. Bazaliy G.A., Ilnitskaya G.D., Oleinik N.A., Tsyba N.N. Study of adsorption-structural and electrophysical characteristics of modified carbon nanotubes. Nanosystems, Nanomaterials, Nanotechnology. 2014. 12(3): 485. [in Russian].
5. Bogatyreva G.P., Marinich M.A., Bazaliy G.A. Research of influence of chemical treatments on physical and chemical properties of carbon nanotubes. Rock-cutting and metal-working tool - equipment and technology of its production and application. (Kyiv: ISM NANU, 2010). 13: 326. [in Russian].
6. Bogatyreva G.P., Sizonenko O.M., Oliinyk N.O. Effect of high voltage electric discharges on the physico-chemical and physico-mechanical characteristics of nanotubes. Naukovi notatky. 35: 23. [in Ukrainian].
7. State Standard of Ukraine. (DSTU 3292-95).
8. Method of determining the specific magnetic susceptibility of powders of superhard materials. (M88 Ukraine 90.256-2004). (Kyiv: ISM NANU, 2004). [in Russian].
9. Bogatyreva G.P. Guidelines for the study of physical and chemical properties of superhard materials. (Kyiv: ISM NANU, 1992). [in Russian].
10. Method of determining the electrical resistivity of dispersed powders of superhard materials (M 23.9-303:2014). (Kyiv: ISM NANU, 2014). [in Russian].
11. Method for determining electrokinetic potential of powders of carbon nanotubes (M 24.1-323:2018). (Kyiv: ISM NANU, 2018). [in Russian].
12. Vyacheslavov A.S., Pomerantseva E.A. Surface area and porosity Measurement by nitrogen capillary condensation method. Methodical development. (Moscow: MSU M.V. Lomonosov, 2006). [in Russian].
13. Gregg S., Sing K. Adsorption Surface Area and Porosity. Second ed. (New York: Academic, 1982).
14. Method of estimating the degree of chemical heterogeneity of the surface of dispersed diamond nanopowders (M 28.5-292:2010). (Kyiv: ISM NANU, 2010). [in Russian].
Downloads
How to Cite
Issue
Section
License
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work.
