共查询到20条相似文献,搜索用时 31 毫秒
1.
Lichun Wang Jinhong Yu Zongliu Tang Pingkai Jiang 《Journal of Materials Science》2010,45(24):6668-6676
A novel flame retardant containing phosphorus–silicon, spirocyclic pentaerythritol bisphosphorate disphosphorylchloride/9,10-dihydro-9-oxa-10-phosphaphanthrene-10-oxide/vinyl
methyl dimethoxysilane (SPDV), has been used to modify multiwalled carbon nanotubes (MWNTs) and the m-MWNTs (MWNTs-g-SPDV) was obtained by the covalent grafting of SPDV onto the surfaces of MWNTs. And then the according poly(ethylene-co-vinyl acetate) nanocomposites were prepared via melt blending. Transmission electron microscopy (TEM) results showed that
a core–shell nanostructure with MWNTs as the hard core and SPDV as the soft shell was formed, and the resultant m-MWNTs can
achieve better dispersion than pristine MWNTs in EVM matrix. Cone calorimeter results showed that better flame retardancy
was obtained for EVM/m-MWNTs nanocomposites. Mechanical measurements showed that the Young’s modulus increases due to the
presence of MWNTs or m-MWNTs. The flammability and mechanical properties of the nanocomposites are strongly dependent on the
dispersion state of nanotubes. 相似文献
2.
Jing Xu Xian-Wen Wei Xiao-Jie Song Xiao-Jing Lu Chang-Chun Ji Yong-Hong Ni Guang-Chao Zhao 《Journal of Materials Science》2007,42(16):6972-6976
Cu–Ag bimetallic nanoparticles with atomic ratio of 2.1:1 and diameter in the range of 15–30 nm were decorated on acid-treated
multi-walled carbon nanotubes by a chemical reduction method, which was characterized by transmission electron microscope
(TEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy
(HRTEM). The Cu–Ag/MWNTs nanocomposites were used to construct a modified electrode toward biosensing of H2O2 with a high sensitivity. The catalytic ability of MWNTs/Cu–Ag toward H2O2 was much better than that of MWNTs/Cu and MWNTs/Ag, which indicated that there is a cooperation effect between Cu and Ag. 相似文献
3.
Valmiki B. Koli Sagar D. Delekar Shivaji H. Pawar 《Journal of materials science. Materials in medicine》2016,27(12):177
In this study, nanocomposites of Fe-doped TiO2 with multi-walled carbon nanotubes (0.1– 0.5?wt. %) were prepared by using sol–gel method. The structural and morphological analysis were carried out with using X-ray diffraction pattern and transmission electron microscopy, which confirm the presence of pure anatase phase and particle sizes in the range 15–20?nm. X-ray photoelectron spectroscopy was used to determine the surface compositions of the nanocomposites. UV–vis diffuse reflectance spectra confirm redshift in the optical absorption edge of nanocomposites with increasing amount of multi-walled carbon nanotubes. Nanocomposites show photoinactivation against gram-positive Bacillus subtilis as well as gram-negative Pseudomonas aeruginosa. Fe-TiO2-multi-walled carbon nanotubes (0.5?wt. %) nanocomposites show higher photoinactivation capability as compared with other nanocomposites. The photoluminescence study reveals that the Fe-TiO2-multi-walled carbon nanotubes nanocomposites are capable to generate higher rate of reactive oxygen species species than that of other nanocomposites. Our experimental results demonstrated that the Fe-TiO2-multi-walled carbon nanotubes nanocomposites act as efficient antibacterial agents against a wide range of microorganisms to prevent and control the persistence and spreading of bacterial infections. 相似文献
4.
O. Yu. Ivanshina M. E. Tamm E. V. Gerasimova A. P. Sirotina S. V. Savilov L. V. Yashina 《Inorganic Materials》2011,47(8):858-863
Using conical multiwalled carbon nanotubes (CNTs), we have prepared Pt/CNT and Pt/TiO2/CNT nanocomposites with an average platinum particle size of 3–5 nm, Pt/Ti molar ratio on the surface in the range 3.5–4,
and C/Pt = 21–22. Titania was deposited onto the CNTs through titanium tetrachloride (TiCl4) hydrolysis. Platinum particles were produced by reducing chloroplatinic acid (H2PtCl6) with sodium borohydride (NaBH4) in the presence of CNTs. The composition and structure of the composites have been studied using X-ray photoelectron spectroscopy,
electron microscopy, X-ray diffraction, and thermogravimetry. The materials have been tested as catalysts for hydrogen oxidation
and oxygen reduction. The results demonstrate that the modification of Pt/CNT with titania enhances the catalytic activity
of the material. 相似文献
5.
Two types of molybdenum–carbon nanotubes and molybdenum treated carbon nanotubes/titania composites were prepared using a
sol–gel method. These composites were characterized comprehensively by the Brauer–Emett–Teller (BET) surface area, scanning
electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, X-ray diffraction (XRD), transmission electron microscopy
(TEM) and UV-vis absorption spectroscopy. It was found that the photocatalytic degradation of a methylene blue solution could
be attributed to the combined effects caused by the photo-degradation of titania, the electron assistance of carbon nanotube
network, and the enhancement of molybdenum. The proposed redox mechanism of the photodegradation of methylene blue on Mo-CNT/TiO2 composites is suggested. 相似文献
6.
O. Yu. Ivanshina M. E. Tamm E. V. Gerasimova M. P. Kochugaeva M. N. Kirikova S. V. Savilov L. V. Yashina 《Inorganic Materials》2011,47(6):618-625
Pt/CNT nanocomposite materials with an average platinum particle size of 3–5 nm and platinum content of 13–28 wt % have been
prepared by reducing chloroplatinic acid, H2PtCl6, in the presence of conical carbon nanotubes. The effect of synthesis conditions on the average platinum particle size, total
platinum content, and surface composition of the nanocomposites has been studied using X-ray photoelectron spectroscopy, IR
spectroscopy, electron microscopy, X-ray diffraction, and thermogravimetry. The materials have been tested as catalysts for
hydrogen oxidation and oxygen reduction. Their performance has been assessed by cyclic and steady-state voltammetric techniques.
The structure and composition effects on the electrocatalytic properties of the nanocomposites are discussed. 相似文献
7.
H. Q. Wu D. M. Xu Q. Wang Y. Z. Yao Q. Y. Wang G. Q. Su 《Bulletin of Materials Science》2008,31(5):801-806
Fe46Co35Ni19/CNTs nanocomposites have been prepared by an easy two-step route including adsorption and heat treatment processes. We investigated
the effect of heat treatment conditions on structure, morphology, nanoparticle sizes and magnetic properties of the Fe46Co35Ni19 alloy nanoparticles attached on the carbon nanotubes by X-ray powder diffraction (XRD), scanning electron microscopy (SEM),
high-resolution transmission electron microscopy (HRTEM), energy-disperse X-ray spectroscopy (EDS) and vibrating sample magnetometer
(VSM). When the reducing temperature changes from 300–450°C, a transition of the crystalline structure from bcc phase to fcc-bcc dual phase and an increase in particle size of Fe46Co35Ni19 nanoparticles together with a local maximum at 350°C are observed. Meanwhile, the saturation magnetization (M
s) for Fe46Co35Ni19 nanoparticles increases with the increase of reducing temperature and the coercivity (H
c) decreases rapidly with a local minimum at 350°C. When the reducing time (tr) changes from 2–5 h, bcc phase is predominant in the Fe46Co35Ni19 alloy particles. Both the particle size and M
s have a maximum at tr = 3 h, and the H
c reaches a maximum at tr = 4 h. 相似文献
8.
Zhenbao Liu Yanfei Liu Dongming Peng 《Journal of materials science. Materials in medicine》2014,25(4):1033-1044
Hydroxylation of carbon nanotubes (CNTs) can enhance their dispersibility in water, and allows the capability to conjugate with other molecules for the expected applications. However, the cytotoxicity of hydroxylated CNTs has not been thoroughly investigated. Here, we compared the cytotoxicity of hydroxylated multi-walled carbon nanotubes (MWCNTs–OH) on a human cell line with that of pristine multi-walled carbon nanotubes (p-MWCNTs). We showed that while both MWCNTs–OH and p-MWCNTs induced apoptosis in a time- and dose-dependent manner, MWCNTs–OH triggered a significantly milder cytotoxic response than that of p-MWCNTs. We further showed that such attenuated response could be attributed to a reduced disruption of the mitochondrial membrane potential (MMP), leading to the attenuation of both cytochrome c (cyt-c) release and activation of caspases. These findings suggest that MWCNTs–OH, could be more biocompatible for in vivo applications than that of p-MWCNTs by limiting the activation of the mitochondrial mediated apoptotic pathway. 相似文献
9.
Majid Arvand Bahareh Palizkar 《Materials science & engineering. C, Materials for biological applications》2013,33(8):4876-4883
In this work, using of amine-functionalized TiO2/multi-walled carbon nanotubes (NH2-TiO2-MWCNTs) nanocomposite for modification of glassy carbon electrode (GCE) was investigated. The nanocomposite was characterized by Fourier transformed infrared spectroscopy, transmission electron microscopy and scanning electron microscopy. The efficiency of modified electrode for electrocatalytic the oxidation of olanzapine was studied by cyclic voltammetry, square wave voltammetry and chronoamperometry. The electrochemical measurements were carried out in phosphate-buffered solution (PBS, pH 5.0). The NH2-TiO2-MWCNTs/GCE provided high surface area and more sensitive performance. The charge transfer coefficient (α) and the apparent charge transfer rate constant (ks) were calculated to be equal to 0.42 and 0.173 s? 1, respectively. The square wave voltammetry exhibited two linear dynamic ranges and a detection limit of 0.09 μM of olanzapine. In addition, the modified electrode was employed for the determination of olanzapine in pharmaceutical and human blood serum samples in order to illustrate the applicability of proposed method. 相似文献
10.
Xue-Gang Tang Meng Hou Jin Zou Rowan Truss Mingbo Yang Zhonghua Zhu 《Composites Science and Technology》2012
Bud-branched nanotubes, fabricated by growing metal particles on the surface of multi-wall carbon nanotubes (MWCNTs), were used to prepare poly(vinylidene fluoride) (PVDF) based nanocomposites. The results of differential scanning calorimetry (DSC) showed that the introduction of the MWCNTs and bud-branched nanotubes both increased the crystallization temperature, while no significant variation of Tm (melting temperature), ΔHc (melting enthalpy) and ΔHm (crystallization enthalpy) occurred. The results of wide angle X-ray diffraction (WAXD) tests showed that α-phase was the dominated phase for both pure PVDF and its nanocomposites, indicating the addition of the MWCNTs and bud-branched nanotubes did not alter the crystal structures. Dynamic mechanical analysis (DMA) tests showed that bud-branched nanotubes were much more efficient in increasing storage modulus than the smooth MWCNTs. In addition, no significant variation of the Tg (glass transition temperature) was observed with the addition of MWCNTs and bud-branched nanotubes. Tensile tests showed that the introduction of MWCNTs and bud-branched nanotubes increased the modulus. However, a dramatic decrease in the fracture toughness was observed for PVDF/MWCNTs nanocomposites. For PVDF/bud-branched nanotubes nanocomposites, a significant improvement in the fracture toughness was observed compared with PVDF/MWCNTs nanocomposites. 相似文献
11.
Hua-Qiang Wu Pin-Shi Yuan Hong-Yan Xu Dong-Mei Xu Bao-You Geng Xian-Wen Wei 《Journal of Materials Science》2006,41(20):6889-6894
Fe–Co alloy nanoparticles with different size were attached on the carbon nanotubes through adjusting the ratio of the metal
to carbon in the mixed solution of nitrate with Fe:Co = 1:1 (molar ratio) via wet chemistry. X-ray powder diffraction (XRD),
transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and energy-dispersive X-ray
spectrometry (EDX) indicated that the Fe–Co alloy nanoparticles attached on the surface of carbon nanotubes has body-centered
cubic (bcc) structure, with sizes in the range of 13–25 nm and in the shape of spheroids. Magnetization measurements indicated
that both the coercivities and the saturation magnetizations altered with size changes of the Fe–Co alloy nanoparticles. The
saturation magnetization decreases with decreasing the Fe–Co alloy nanoparticles’ sizes. A decrease in coercivity with increasing
Fe–Co size together with a local maximum coercivity at size of ca. 15 nm is visible. A linear relationship between the inverse particle diameter and the coercivity was found for larger particles.
These demonstrated that the chemical method here is promising for fabricating Fe–Co alloy nanoparticles coated on carbon nanotubes
for magnetic storage applications. 相似文献
12.
Mirza Nadeem Ahmad Maria Nadeem Yuhong Ma Wantai Yang 《Journal of Materials Science》2010,45(20):5591-5597
Photochemical modification of single-walled carbon nanotubes (SWCNTs) was carried out by covalent attachment of 2-propanol-2-yl
radicals on the surface of SWCNTs, which were engendered by the photolysis of 1-[4-(2-Hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one
(HPHMP) under ultraviolet (UV) light. Pristine single-walled carbon nanotubes (p-SWCNTs) were dispersed in acetone along with
HPHMP photoinitiator. After that, the mixture was irradiated by UV light to generate the free radicals which were introduced
onto the surface of SWCNTs. The modification of SWCNTs was supported by UV/visible spectroscopy, Fourier transform infrared
spectroscopy (FT-IR), Raman spectroscopy, thermal gravimetric analysis–mass spectrometry (TGA–MS), and transmission electron
microscopy (TEM). UV/visible results revealed the loss of van Hove singularities due to covalent modification. The modification
was further verified by FT-IR showing the signals at 3421 and 1100 cm−1 due to stretching and bending of O–H group, respectively. Moreover, other peaks at 2927 and 2858 cm−1 indicated the asymmetric and symmetric stretching modes of aliphatic C–H bond, respectively. Raman spectra illustrated that
the intensity ratio of the tangential mode to the disorder mode (I
G/I
D), for modified SWCNTs (F-SWCNTs), decreased nearly four times than p-SWCNTs. TGA–MS also evidenced the signal corresponding
to m/z 59 at 400 °C indicating the presence of 2-propanol-2-yl groups. TEM and dispersibility data demonstrated that the sidewall
modification detached the bundled structure, enhanced the dispersion in common organic solvents and retained the original
size of SWCNTs without hefty modification, which could cut or damage the nanotubes. 相似文献
13.
Cr2O3–CNT/TiO2 composites derived from chromium acetylacetonate, multi-walled carbon nanotubes (MWCNT) and titanium n-butoxide (TNB) were prepared, and the photocatalytic activity of the Cr2O3–CNT and CNT/TiO2 composites was examined. The Cr2O3–CNT/TiO2 composites were characterized by BET surface area measurement, X-ray diffraction, transmission electron microscopy, and energy
dispersive X-ray analysis. The photocatalytic activity was determined from the decomposition of methylene blue (MB) under
visible light irradiation. Methylene blue was photodegraded successfully in the presence of the Cr2O3–CNT/TiO2 composite under visible light irradiation. 相似文献
14.
Falk Heinroth Dominic Gruss Sven Müller Florian Waltz Julia Martynczuk Armin Feldhoff Peter Behrens Michael Wiebcke 《Journal of Materials Science》2010,45(6):1595-1603
Having new potential applications in forging processes in mind, composites of an ordered mesoporous carbon and luminescent
metal phosphate nanocrystals were synthesized for the first time. Three kinds of CMK-3/CePO4:Tb nanocomposites were prepared by treating a mesoporous CMK-3 host with different lanthanide phosphate precursor solutions.
Characterization of the obtained nanocomposites by small-angle X-ray scattering, wide-angle X-ray diffraction, transmission
electron microscopy, thermogravimetry, and nitrogen physisorption analysis showed that in two cases, the nanocrystals (ca.
2–3 nm in size) were located inside the mesopores, whereas in the third case the nanocystals (ca. 6 nm in size) merely adhered
to the outer surfaces of the carbon particles. The CMK-3 and the two nanocomposites had ordered hexagonal structures (space
group p6mm); all the materials possessed amorphous carbon walls. After combustion of the nanocomposites, the residues upon excitation
with UV light exhibited the typical green luminescence of Tb3+. A preliminary evaluation of the lubrication properties of the CMK-3 and one nanocomposite material was performed. The friction
factors determined by means of ring upsetting tests revealed that the carbon materials were able to lower frictional forces
although they were 3–4 times less efficient than a commercial graphite-based reference lubricant. 相似文献
15.
Yuxin ChenHongchen Gu 《Materials Letters》2012,67(1):49-51
Uniform Fe3O4 nanoparticles with diameters of 3-5 nm are successfully decorated onto the external walls of multiwall carbon nanotubes (MWCNTs) by in situ high-temperature decomposition of Fe(acac)3 in polyol solution under the irradiation of microwave. With this method, reaction time of forming Fe3O4-MWCNTs nanocomposites has been significantly shortened to 15 min. The resulting Fe3O4-MWCNTs nanocomposites show superparamagnetic property at room temperature and can be remained as stable aqueous dispersion for 2 months. Longitudinal relaxivity (r1) and transverse relaxivity (r2) of the magnetic MWCNTs are 8.34 Fe mM−1 S−1 and 146 Fe mM−1 S−1 respectively. The much higher r2 value and the obvious change in the gray scale of MR images confer the Fe3O4-MWCNTs nanocomposites as potential candidates for T2-weighted MRI contrast agents. 相似文献
16.
Yılmaz Simsek Lutfi Ozyuzer A. Tugrul Seyhan Metin Tanoglu Karl Schulte 《Journal of Materials Science》2007,42(23):9689-9695
The aim of this study is to investigate temperature dependence of electrical conductivity of carbon nanotube (CNT)/polyester
nanocomposites from room temperature to 77 K using four-point probe test method. To produce nanocomposites, various types
and amounts of CNTs (0.1, 0.3 and 0.5 wt.%) were dispersed via 3-roll mill technique within a specially formulized resin blend
of thermoset polyesters. CNTs used in the study include multi walled carbon nanotubes (MWCNT) and double-walled carbon nanotubes
(DWCNT) with and without amine functional groups (–NH2). It was observed that the incorporation of carbon nanotubes into resin blend yields electrically percolating networks and
electrical conductivity of the resulting nanocomposites increases with increasing amount of nanotubes. However, nanocomposites
containing amino functionalized carbon nanotubes exhibit relatively lower electrical conductivity compared to those with non-functionalized
carbon nanotubes. To get better interpretation of the mechanism leading to conductive network via CNTs with and without amine
functional groups, the experimental results were fitted to fluctuation-induced tunneling through the barriers between the
metallic regions model. It was found that the results are in good agreement with prediction of proposed model. 相似文献
17.
Edson Giuliani R. Fernandes Demetrio Artur W. Soares Alvaro Antonio Alencar De Queiroz 《Journal of Materials Science: Materials in Electronics》2008,19(5):457-462
The electrical properties of polyaniline nanotubes-aluminum like Schottky diode are described. Polyaniline nanotubes (PANI)
were deposited on aluminum thin films using the polarographic technique. The nanotubes were characterized by scanning electron
microscopy (SEM) and UV-Vis absorption spectra. The electrical properties of the heterojunction PANI-Al were examined. The
current density–voltage (J × V) profile has shown a behavior typical of Schottky diode, with ideality factor (n) of 6.76 and ϕ
b of 0.70 eV. Impedance spectroscopy data apparently shows that the resistance dominated the AC behavior of the PANI-Al system.
The equivalent circuit is composed from a resistor in series with a parallel resistor–capacitor circuit. The results indicate
that polyaniline nanotubes may be interesting to the development of electro-optical devices with 2D structure. 相似文献
18.
Qingzhi Luo Xueyan Li Desong Wang Yanhong Wang Jing An 《Journal of Materials Science》2011,46(6):1646-1654
A series of polypyrrole (PPy)/titanium dioxide (TiO2) nanocomposites were prepared in different polymerization conditions by ‘in situ’ chemical oxidative polymerization. The
nanocomposites were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectra (FT-IR), X-ray
photoelectron spectroscopy spectra (XPS), and UV–Vis diffuse reflectance spectra. The photocatalytic degradation of methyl
orange (MO) was chosen as a model reaction to evaluate the photocatalytic activities of TiO2/PPy catalysts. The results show that a strong interaction exists at the interface between TiO2 and PPy, the deposition of PPy on TiO2 nanoparticles can alleviate their agglomeration, PPy/TiO2 nanocomposites show stronger absorbance than neat TiO2 under the whole range of visible light. The obtained PPy/TiO2 nanocomposites exhibit significantly higher photocatalytic activity than the neat TiO2 on the degradation of MO aqueous solution under visible and UV light illumination. The reasons for improving the photocatalytic
activity were also discussed. 相似文献
19.
We have studied the working optical characteristics and electron kinetic coefficients of a short-wavelength, electric discharge
exciplex-halogen UV-VUV lamp employing a mixture of argon and chlorine with a total pressure of P = 0.5–10 kPa. The lamp operates on a system of broadened electron-vibrational bands of ArCl (175 nm) and chlorine (200, 258
nm) molecules, which overlap to form a continuum in the spectral range of 160–260 nm. It is established that the optimum mixtures
are those with p(Ar) − p(Cl2) = (2–4)−(0.15–0.30) kPa. The average output power of the short-wavelength radiation is 1–2 W at an efficiency of ∼5%. The
electron energy distribution functions (EDFs) and the discharge plasma parameters have been calculated by solving the Boltzmann
equation for a gas mixture with the experimentally determined optimum composition in the range of E/P values from 1 to 200 V/(cm Torr), where E is the electric field strength and P is the total gas pressure. Using the obtained EDFs, the electron transport characteristics, specific discharge power losses
for the main elementary processes, and rate constants of electron processes are determined. 相似文献
20.
《Journal of Experimental Nanoscience》2013,8(1):52-60
Multi-wall carbon nanotubes (MWCNTs) were prepared by spray-pyrolysis of a botanical hydrocarbon, alpha-pinene and ferrocene as the catalyst at 700–1000°C. The MWCNTs were analysed by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy and X-ray diffraction. The microscopy studies show the formation of carbon nanotubes with diameters between 20 and 30 nm and length greater than 100 µm. Raman spectroscopy revealed that the alpha-pinene-grown carbon nanotubes were graphitised showing both the D and G bands at 1330 and 1590 cm?1, respectively, and that the corresponding intensity band ratio (I D/I G) varied with respect to temperature formation. 相似文献