31 research outputs found
STUDY OF THE COMPLEX FORMATION OF Ti(IV) WITH THE AZO DERIVATIVE OF PYROGALLOL IN THE PRESENCE OF A THIRD COMPONENT
Synthesis of fe/ni bimetallic nanoparticles and application to the catalytic removal of nitrates from water
This work investigated the effectiveness of zerovalent iron and Fe/Ni bimetallic nanoparticles in the treatment of water polluted by a high concentration of nitrates. Nanoparticle synthesis was carried out by a sodium borohydride reduction method in the presence of sodium oleate as a surfactant. The particles were characterized by XRD and SEM. Batch experiments were conducted on water samples contaminated by 300 mg L−1 of nitrate. The parameters investigated were the Fe/Ni dosage (0.05, 0.1, 0.2, 0.3, and 0.4 g L−1) and the reaction pH (unbuffered; buffered at pH = 3; initial pH = 3, 5, and 10). The results showed that almost complete nitrate removal (>99.8%) was always achieved after 15 min at a concentration of bimetallic nanoparticles higher than 0.2 g L−1 . The optimization of bimetallic nanoparticle dosage was carried out at a fixed pH. Kinetic study tests were then performed at different temperatures to assess the effect of temperature on the nitrate removal rate. By fixing the pH at acidic values and with an operating temperature of 303 K, nitrates were completely removed after 1 min of treatment
Structure and thermal properties of copper-polypropylene based nanocomposites
Polymer nanocomposites based on PP/Cu were obtained by the combining of ex-situ casting solution and hot pressing methods. The structure of polymer nanocomposites was characterized by XRD, SEM, EDS, AFM and FT-IR spectroscopy analysis. The thermal properties were analyzed using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It was found that the addition of copper nanoparticles to the PP polymer matrix increases the thermal stability of the polymer, and this thermal stability reaches its maximum value at 3% content of copper nanoparticles in the polymer. The reason for the increase in the thermal properties of nanocomposites is associated with the formation of a more perfect, dense and ordered structure of PP-based composites and the fact that nanoparticles play the role of a nucleus of crystallization for polymer matrices
Erratum to: “The Effect of the Temperature–Time Mode of Crystallization on the Morphology and Properties of Nanocomposites Based on Polypropylene and Cadmium Sulfide”
Correction to: Influence of magnetite nanoparticles on the dielectric properties of metal oxide/polymer nanocomposites based on polypropylene (Russian Physics Journal, (2018), 60, 9, (1572-1576), 10.1007/s11182-018-1253-5)
The name of the first author should read A. М. Maharramov
Influence of Temperature-Time Mode of Crystallization on Electrophysical Characteristics of the Polypropylene/Magnetite Nanocomposite
Influence of Polarization Processes on the Morphology and Photoluminescence Properties of PP/TiO₂ Polymer Nanocomposites
The paper reports of synthesis and investigation of polymeric nanocomposites based on isotactic polypropylene and titanium dioxide nanoparticles PP+TiO₂ (PPT). The structure of the PPT nanocomposites was studied by scanning electron and atomic force microscopy. There was also studied the influence of the polarization process by corona discharge on the structure and photoluminescence properties of PPT nanocomposites. It was found that intensity of the photoluminescence after the polarization increases, and this depends on the concentration of titan dioxide nanoparticles in the polymer matrix. It was shown that rms roughness for non-polarized sample compositions is 60-100 nm, whereas for polarized samples after the corona discharge polarization, makes 20-40 nm, i.e. there takes place grinding of the structural elements. It is supposed that, in the composite there forms sufficiently high internal local field, due to the boundary charges, so under the influence of this field there were excited additional luminescent centers, and as a result, after the polarization there was observed the increase of luminescence intensity
The effect of the temperature-time mode of crystallization on the morphology and thermal properties of nanocomposites based on polypropylene and magnetite (Fe3O4)
In the present study, the influence of the temperature–time mode of crystallization (TTC) on the morphology and thermal properties of PP/Fe3O4 nanocomposite materials was investigated. The morphology of the nanocomposites prepared in different TTC mode was studied by atomic force microscope. AFM study shows that the root mean square roughness of samples is 90–95, 50, 21 nm for PP/Fe3O4@20, PP/Fe3O4@200 and PP/Fe3O4@20000 respectively. Thermo gravimetric analysis was employed to investigate the thermal stability of PP/Fe3O4 nanocomposites obtained applying different TTC modes. It was found that thermal stability of water-cooled nanocomposite samples (PP/Fe3O4@200) is higher than the thermal stability of samples obtained with other two modes. Crystallization and melting behaviors of nanocomposite samples prepared in different TTC mode have been studied with DSC method and the degree of crystallinity of samples was calculated. It was found that, degree of crystalization decreases with increasing of cooling rate. The XRD patterns of samples produced in different TTC modes also correlate well with this result
Influence of magnetite nanoparticles on the dielectric properties of metal oxide/polymer nanocomposites based on polypropylene
Structure and dielectric properties of polymer nanocomposites based on isotactic polypropylene and iron oxide
(Fe3O4) nanoparticles are studied. Distribution of magnetite nanoparticles in a polymer matrix was studied by
scanning electron microscopy (SEM, Carl Zeiss). Dielectric properties of nanocomposites were examined by
means of E7-21 impedance spectrometer in the frequency range of 102–106 Hz and temperature interval of
298–433 K. The frequency and temperature dependences of the dielectric permittivity ε, as well as the
temperature dependence of log (ρ) were constructed. It is shown that introduction of the magnetite (Fe3O4)
nanoparticles into a polypropylene matrix increases the dielectric permittivity of nanocomposites. An increase
in the dielectric permittivity is explained by the increase in the polarization ability of nanocomposites. It is
found that a decrease in the specific resistance with increasing temperature up to 318 K is associated with an
increase in the ionic conductivity of nanocomposites. An increase in the resistance at temperatures higher than
358 K is due to the destruction of the crystalline phase of the polymer, as a result of which the distance between
the Fe3O4 nanoparticles increases