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Wyświetlanie 1-7 z 7
Tytuł:
Effect of the Silanization Processes on the Properties οf Oxidized Multiwalled Carbon Nanotubes
Autorzy:
Scheibe, B.
Borowiak-Palen, E.
Kalenczuk, R.
Powiązania:
https://bibliotekanauki.pl/articles/1807640.pdf
Data publikacji:
2009-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.65.Mq
81.07.De
61.48.De
65.80.-g
68.37.Lp
Opis:
This paper presents the results of the research on the effect of the two different silanization methods on the thermal and structural properties of oxidized multiwalled carbon nanotubes. As-purified material was oxidized in the mixture of nitric and sulfuric acids. An oxidized material was divided into two parts which underwent two silanization treatments by 3-aminopropyltriethoxysilane (APTES). The first experiment (I) was performed at room temperature in acetone (pH 7) for 30 min. The second experiment (II) involved a hydrolysis of APTES at 40°C in water (pH 4) for 3 h. The functionalization extent of the samples at each step of the preparation was investigated by the Raman spectroscopy. The presence of the functional groups on the nanotubes surface have been studied via the Fourier transform infrared spectroscopy (FT-IR). The quantity of the external moieties introduced on multiwalled carbon nanotubes surface after oxidation process was estimated by the Boehms titration method. The high resolution transmission electron microscopy analysis allowed us to observe the changes of the morphology of the investigated carbon nanotubes. The influence of the silanization processes on the thermal stability of multiwalled carbon nanotubes was thoroughly studied by thermogravimetry analysis. There was observed a significant increase of the thermal stability of the multiwalled carbon nanotubes samples upon silanization treatment in respect of pristine and oxidized multiwalled carbon nanotubes.
Źródło:
Acta Physica Polonica A; 2009, 116, S; S-150-S-155
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ab Initio Study of Functionalized Carbon Nanotubes
Autorzy:
Milowska, K.
Birowska, M.
Majewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1791295.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
31.15.ae
31.15.E-
61.46.Fg
61.48.De
73.22.-f
81.07.De
Opis:
In the present paper, we study the stability of (9, 0), (10, 0), (11, 0) carbon nanotubes functionalized with simple organic molecules $-CH_{n}$ (for n = 2, 3, 4). Our studies are based on ab initio calculations within the framework of the density functional theory. We determine binding energies of the functionalized carbon nanotubes and the changes in the geometry and electronic structure caused by the functionalization. We observe the characteristic effects such as rehybridization of the bonds induced by fragments attached to carbon nanotubes and pentagon/heptagon (5/7) defects in $-CH_{2}$ functionalized carbon nanotubes. We study also dependence of the binding energies of the functionalized carbon nanotubes on the density of the adsorbed molecules and diameter of the single-wall carbon nanotubes. Our calculations reveal that the $-CH_{2}$ fragments exhibit the strongest cohesion and we determine the critical density of the $-CH_{2}$ fragments which could be adsorbed.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 841-843
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Analysis of Magnetic Inclusions in Nanomaterials Based on Multiwall Carbon Nanotubes
Autorzy:
Brzózka, K.
Krajewski, M.
Małolepszy, A.
Stobiński, L.
Szumiata, T.
Górka, B.
Gawroński, M.
Wasik, D.
Powiązania:
https://bibliotekanauki.pl/articles/1032146.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.Qr
61.46.Fg
61.48.De
75.50.Tt
75.75.Cd
81.07.De
Opis:
Functionalized multiwall carbon nanotubes as well as nanocomposite based on that material covered by nanoparticles composed of iron oxides were the subject of investigations. In order to identify all iron-bearing phases including those reported on the base of previous X-ray diffraction measurements, the transmission Mössbauer spectroscopy was utilized. The experiments were carried out both at room temperature and also at low temperatures. It was stated that in the investigated nanotubes some impurities were present, originating from the catalyst remains, in form of Fe-C and α -Fe nanoparticles. The Mössbauer spectra collected for the nanocomposite showed a complex shape characteristic of temperature relaxations. The following subspectra related to iron-based phases were identified: sextet attributed to hematite, with hyperfine magnetic field reduced due to the temperature relaxations, sextet corresponding to iron carbide as well as two doublets linked to superparamagnetic hematite and ferrihydrites.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 863-865
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Band Structure of Coiled Carbon Nanotubes
Autorzy:
Milošević, I.
Damnjanović, M.
Powiązania:
https://bibliotekanauki.pl/articles/1503008.pdf
Data publikacji:
2011-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.48.De
73.22.-f
81.07.-b
Opis:
More than fifteen years have passed since the first report of experimental evidence of regularly coiled carbon nanotubes, but, the structure, formation mechanism and theoretical aspects of these nanotubes still remain unresolved. We propose model of hexagonal, helically coiled single wall carbon nanotubes, determine their line group symmetry and calculate electronic band structure of the relaxed configurations by means of fully symmetry adopted density functional tight binding method implemented into the POLSym code. Electrical properties of the straight and coiled carbon nanotubes of different chiralities are compared and analyzed.
Źródło:
Acta Physica Polonica A; 2011, 120, 2; 221-223
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and Characterization of ZnO Nanopowders and ZnO-CNT Nanocomposites Prepared by Chemical Precipitation Route
Autorzy:
Gültekin, D.
Alaf, M.
Akbulut, H.
Powiązania:
https://bibliotekanauki.pl/articles/1399778.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.46.Df
81.07.Wx
81.05.Dz
61.48.De
81.20.Fw
Opis:
The aims of this work are synthesis of ZnO nanopowders and producing nanocomposites by mixing with carbon nanotubes. ZnO nanopowders have been synthesized by chemical precipitation route. Different amount of collected nanosized Zn-based precipitates and chemically oxidized carbon nanotubes powder have been mix together and annealed at 400°C. Characterization of produced nanopowders and nanocomposites have been carried out by X-ray diffractometer and scanning electron microscope.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 274-276
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation and Characterisation of Silicon/Carbon Nanotube Composite Electrodes for Li-Ion Battery Systems
Autorzy:
Cetinkaya, T.
Tocoglu, U.
Cevher, O.
Guler, M.
Akbulut, H.
Powiązania:
https://bibliotekanauki.pl/articles/1399951.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.uf
61.48.De
81.20.Ev
81.07.-b
Opis:
Silicon powders and different amounts of multiwalled carbon nanotube were mechanically alloyed in polyacrynitrile solution via high speed planetary ball milling. Produced composite was characterised via X-ray diffraction pattern, scanning electron microscopy, energy dispersive spectroscopy and thermogravimetric analysis.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 398-400
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preliminary Investigations into the Purification and Functionalization of Multiwall Carbon Nanotubes
Autorzy:
Trykowski, G.
Biniak, S.
Stobinski, L.
Lesiak, B.
Powiązania:
https://bibliotekanauki.pl/articles/1536523.pdf
Data publikacji:
2010-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.48.De
81.16.Be
07.57.Ty
82.80-d
68.37.Hk
Opis:
The purification and functionalization of commercial multiwall carbon nanotubes was investigated. Carbon nanotubes (CNT CO., Ltd, Korea) were treated with boiling concentrated HNO_3 under a reflux condenser for about 50 h at 120°C in order to purify and oxidize the raw material. The oxidized multiwall carbon nanotubes were rinsed with deionized water until stabilization of the filtrate pH. Measurement techniques included elemental analysis (CHN), scanning electron microscopy with energy dispersive X-ray spectrometer, inductively coupled plasma mass spectrometry, Fourier transform infrared spectroscopy and thermal analysis. With the measurement techniques used the following information was obtained: CHN analysis provided information about the quantitative composition of the following elements carbon, hydrogen, nitrogen, scanning electron microscopy imaging provided information on shape, thickness and length of the nanotubes, energy dispersive X-ray spectrometry analysis of information about surface atomic composition of the quantitative analysis, inductively coupled plasma mass spectrometry quantitative analysis of the atomic composition (metals, especially Fe, Al), the Fourier transform infrared studies provided information about qualitative analysis of surface functional groups $C_{x}O_{y}H_{z}$ (COOH, OH, COO) and thermal gravimetric-differential thermal analysis - quantitative analysis of thermal decomposition products. It was found that oxidation leads to the removal of amorphous carbon and forms mainly carboxylic functional groups linked to the nanotubes. The Fourier transform infrared spectra indicate the presence of some other structures, like ketone (quinone), acid anhydride, ether and epoxy groups. Nitric acid treatment also effectively removes aluminum oxide catalyst and iron catalyst from commercial multiwall carbon nanotubes.
Źródło:
Acta Physica Polonica A; 2010, 118, 3; 515-518
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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