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Combined hybrid nanocomposites based on PVDF+CdS/ZnS were developed and studied. The structure of nanocomposites was characterized by XRD, SEM, EDS, UV- spectroscopic techniques. XRD analysis shows...

The structure and dielectric properties of new hybrid polymer nanocomposites based on polyvinylidene fluoride (PVDF) and CdS and ZnS nanoparticles (NPs) have been studied. It was established that ZnS and CdS NPs, when added at low concentrations, define the structure of the host polymer matrix, and new polar groups and stable charge traps arise, which, in turn, leads to an increase in the dielectric permittivity and polarizing ability of the nanocomposites based on PVDF + CdS/ZnS NPs. As the NP concentration is increased, the NPs start to behave like a separate dispersion phase, and the conductivity of nanocomposites grows as the content of this phase increases, which results in the nanocomposite’s polarizing ability gradually diminishing.

There have been presented investigation results of electrothermopolarization influence on electret properties and charge state of PE + PbCrO4nanocomposition. Structural change of PE + PbCrO4 nanoco...

In this study have been prepared optically transparent polymeric nanocomposites based on PP/YSZ by combination of ex-situ and hot pressing methods. The structure of the synthesized nanocomposites was studied by XRD analysis, UV spectroscopy, scanning electron microscopy. The optical and photoluminescent (PL) properties of polymer nanocomposites were investigated. It was found that with an increase in the concentration of YSZ nanoparticles in the PP matrix to 3% of the content of nanoparticles, the PL intensity increases, with a further increase in the nanoparticles content, the PL intensity decreases. This is explained by the fact that with an increase in the concentration of YSZ nanoparticles, their size increases and their specific surface decreases, and this leads to a decrease in the contacting region between the polymer and the nanoparticle. A decrease in the interphase boundary leads to a decrease in interphase interactions, and this in turn leads to a change in the PL intensity. It was also shown that the PL intensity for nanocomposites at all wavelengths increases with increasing annealing temperature to 120°C, and then decreases. Possible reasons for a significant increase in the PL intensity after thermal annealing are the redistribution of charge carriers between levels in the band gap or the recharging of recombination centers and the removal of organic compounds adsorbed on the surface of nanocomposites.

In this study, the production and the EM-wave absorption properties of the polymer nanocomposites were investigated. The two- and three-phase polymer nanocomposites on the base of the PVDF matrix, multi-walled carbon nanotubes, and magnetite nanoparticles were produced by the in-situ method. With the help of XRD and SEM methods, produced nanocomposites were analyzed. Measurement of the absorption coefficient of the nanocomposites with different filler concentrations shows that the maximum effect was obtained for the nanocomposite, with 20 wt% of MWCNT in the PVDF matrix. Very close value to maximum was also, got for a nanocomposite, which contained 10 wt% of MWCNT and 5 wt% of Fe3O4 in the PVDF matrix. These results were related to energy dissipation at the high-frequency region, depending on the components fraction in the nanocomposites.

Copper nanoparticles via chemical reduction of copper sulfate by sodium borohydride in the presence of sodium oleate stabilizing agent have been synthesized and stabilized. X-ray phase analysis has...

In given paper, were studied optical properties of nanocomposites obtained on base of PP + PbS/CdS with different concentration. The UV–Vis spectral analysis indicated that the optical band gap of the system was decreases with increasing of concentration of semiconductor nanoparticles inside the polymer. This can be explained by increasing of size of nanoparticles due to agglomeration of nanoparticles with increasing of concentration. SEM analysis of PP + PbS/CdS based nanocomposites showed that particle size in PP + 3% PbS/CdS, PP + 5% PbS/CdS, and PP + 15% PbS/CdS nanocomposites was the range of 5–10 nm, 12–18 nm, and 18–34 nm in respectively. At the same time, were investigated luminescence spectra of nanocomposites with different concentrations obtained on the base of PP + PbS/CdS. It has been established that the highest luminescence intensity is observed in nanocomposites PP + 3% PbS/CdS. This can be explained by the fact that in this concentration the luminescent centers are more active and more optimal structures are formed. At the same time, low luminescence intensity in PP + 15% PbS/CdS nanocomposites can be explained by reduction of the luminescence surface and weakening of activity of centers due to the growing size of particles by agglomerating with increasing of concentration.

In the present study, the influence of the temperature–time mode of crystallization (TTC) on the electrophysical properties of polymer-based PP + Fe3O4 nanocomposite materials was investigated. Also, the effect of the temperature-time mode of crystallization of nanocomposites on the negative magnetoresistance (NMR) effect that observed in this material was investigated. It was found that dielectric permittivity of polymer nanocomposites rises with increasing of cooling rate. The cooling rate of nanocomposites after hot-pressing also affects the NMR effect of these materials. The conductivity of the material under the influence of magnetic field improves with increasing of its cooling rate, which leads to increasing of NMR effect.

Poly(vinyl chloride) (PVC)–cadmium sulfide (CdS) nanocomposite films were successfully synthesized by ex situ solution casting method. Scanning electron microscopy showed that CdS nanoparticles are well monodispersed in the PVC matrix. From the ultraviolet (UV) spectra of nanocomposites, the width of the forbidden band for polymer nanocomposites was determined by extrapolation method. UV-visible optical spectra revealed that the optical band of nanocomposites is increased with increasing concentration of CdS nanoparticles in the PVC matrix. It was found that the band gap is 3.8 eV for PVC-3% CdS nanocomposites, 2.7 eV for PVC-5% CdS, and 2.35 eV for PVC-10% CdS nanocomposites. Photoluminescence spectrum of PVC-CdS-based nanocomposites shows two luminescent peaks at the wavelengths of 436 nm and 472 nm at the luminescence spectrum which belongs to CdS nanoparticles. Photoluminescence study shows that PVC-CdS nanocomposites exhibit a great blue shift (approximately 100 nm) compared with bulk CdS nanoparticles.

A detailed study of the dispersion of magnetite (Fe3O4) nanoparticles in the polypropylene (PP) matrix, the degree of coagulation, and the dependence of magnetic properties of PP + Fe3O4nanocomposites on the size of nanoparticles is reported. The size distribution of nanoparticles in polymer matrix and morphology of the nanocomposites were studied by the means of scanning electron microscope (JEOL JSM-7600 F) and atomic force microscopy (NT-MDT). It was found that when the Fe3O4nanoparticles are introduced into the PP matrix, their coagulation takes place. The increase in the size of the Fe3O4nanoparticles depends on their volume content in the polymer matrix, the viscosity of polymer, mixing time, and so on. The magnetic properties of PP + Fe3O4nanocomposites were experimentally and theoretically studied. It was found that the magnetic hysteresis parameters of the nanocomposites directly depend on the size and concentration of the Fe3O4nanoparticles in the matrix. Theoretical calculations were compared with experimental results obtained from M( H) measurements. Discrepancy between theoretical and experimental magnetic values have been explained.

In the present study, we report about the influence of an external permanent magnetic field on electrical resistivity and dielectric permittivity of PP + Fe3O4 and PVDF + Fe3O4 based nanocomposites...

The structure and dielectric measurements made on the nanocomposites based on PP polypropylen and TiO2 nanoparticles are reported in this paper. It has been defined that, the incorporation of TiO2 ...

It was found that the coagulation of the Fe nanoparticles takes place when they are introduced into the polymer matrix. The increase in particle size depends on their concentration in the polymer matrix, the type and properties of polymer (polar, non-polar, viscosity, etc.), reaction mode, etc. Fe particles, coagulate when they are introduced into the polymer matrix, the oxidation of their surface layer not occur, and the magnetic size does not change, hence, does not change the magnetic characteristics. The magnetic hysteresis parameters depend on the size and concentration of the Fe particles. At the same time, have been shown that at low fields the theoretical and experimental dependence of M(H) correlate to each other very well. The hysteresis has been observed at the polarization of the nanoparticles. The increasing of nanoparticles size led to difference in theoretical and experimental values, that in the theory can be explained by acceptance of nanocluster as single domain particle and their interphase interactions are not taken into account.

In the present study, the effect of size distribution of magnetite nanoparticles in a PVDF matrix on the magnetic properties of PVDF + Fe3O4 nanocomposites was experimentally and theoretically investigated. The size distribution of nanoparticles in polymer matrix and morphology of the nanocomposites were studied by the means of scanning electron microscopy and atomic force microscopy. It was found that when the Fe3O4 nanoparticles are introduced into the polymer matrix, their coagulation takes place. The increase in the size of the particles depends on their concentration in the polymer matrix, the type of polymer (polar, non-polar, its viscosity, etc.), reaction temperatures, etc. In addition, when Fe3O4 nanoparticles are introduced into the polymer network, the oxidation of the surface layer of particles occurs and the magnetic size decreases. Consequently, the reduced magnetic properties may also be observed. The hysteresis loops have been recorded in small magnetic field range. It was found that the magnetic hysteresis parameters depend on the size and concentration of Fe3O4 nanoparticles. Theoretical calculations were compared with experimental results obtained from M(H) measurements. The reasons of differences between theoretical and experimental results have been explained.

In this article, we report about the synthesis of magnetic polymer nanocomposites comprising magnetite (Fe3O4) nanoparticles in a polyethylene (PE) matrix. The structure and composition of nanocomposite materials using scanning electron microscopy and atomic force microscopy have been studied. It has been defined that the agglomeration of nanoparticles does not occur, by increasing the volume content of nanoparticles up to 60%, and Fe3O4 nanoparticles act out like single-domain particles. It has also been revealed that nanocomposites based on PE + Fe3O4 with nanoparticle content in a polymer matrix up to 60% behave like superparamagnetic particles. It has also been revealed that the PE + Fe3O4-based nanocomposites effectively absorb the electromagnetic waves in the high frequency range of 0.1–30 GHz. It is shown that the properties of ultrahigh electromagnetic waves can be varied by varying the thickness of the nanocomposite films and the concentration of Fe3O4 nanoparticles.

The purpose of this study is to investigate the electret properties and charge states of the nanocomposites based on the polyvinylidenefluoride and titanium dioxide nanoparticles. It has been found that, large amount of charges are accumulated in the interface as a result of migration polarization and these charges create rather large internal local field in which the polarization of titanium-dioxide nanoparticles occurs. Calculated, the amount of the charges accumulated in the interfacial layer of nanocomposites, the intensity of the field created by them and the value of charge activation energy of PVDF/TiO2 nanocomposites after polarization from thermally stimulated depolarization (TSD) curves. As well as the thickness of the interphase layer of PVDF/TiO2 nanocomposites was calculated and it has been revealed that, as titanium dioxide content increases in the polymeric matrix, the thickness of the interphase layer increases and reaches at its highest value at 5% volume content of TiO2 nanoparticles, after this it commences to decrease.

Has been studied the effect of polarization under the influence of corona discharge on the photoluminescence properties and charge state of nanocomposites based on polyvinylidene fluoride and zirco...

The effect of a corona discharge on the structure and photoluminescence properties of nanocomposites based on polypropylene (PP) and zirconia is studied. It is shown that polarization under the action of a corona discharge leads to a refinement of the structural elements and an increase in the photoluminescence intensity and the increase depends on the charge concentration. The amount of charges accumulated at the interface between the nanocomposite components is determined by the thermostimulated depolarization (TSD) method; it is found that, during polarization, a large number of electric charges accumulate at the interface between the PP and ZrO2 nanocomposite components. It is revealed that the interfacial charges generate a fairly high internal local field, which excites luminescence centers in the zirconia and, thereby, leads to an increase in the luminescence intensity.

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&minus, 1 of nitrate. The parameters investigated were the Fe/Ni dosage (0.05, 0.1, 0.2, 0.3, and 0.4 g L&minus, 1) and the reaction pH (unbuffered, buffered at pH = 3, initial pH = 3, 5, and 10). The results showed that almost complete nitrate removal (&gt, 99.8%) was always achieved after 15 min at a concentration of bimetallic nanoparticles higher than 0.2 g L&minus, 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.

The influence of corona discharge on the structure and photoluminescence properties of nanocomposites based on polypropylene and zirconium dioxide nanoparticles has been studied. It is shown that a...

In this work we report of functionalization of magnetite nanoparticles by hydroxyl containing diazacrown ether—macroheterocycle (MC) that is able to mimic the properties of natural siderophores. The structure of synthesized crown ether was investigated by NMR, mass-, FTIR spectroscopy methods. The morphology of prepared MC@Fe3O4 nano-ensembles was analysed by scanning electron microscopy SEM, X-ray diffraction XRD analysis methods. The quantitative analysis of nanostructures was determined by atom absorbance spectroscopy as well as on the basis of Lambert–Beer law by UV spectroscopy method. It was found that the synthesized compounds were effective against gram-negative microorganisms Escherichia coli, Klebsiella spp. and gram-positive Staphylococcus aureus, having multi drug resistance properties.

The influence of corona discharge on the electret and charge state of nanocomposites based on isotactic polypropylene and zirconia dioxide nanoparticles has been investigated. It is shown that in the process of polarization under the influence of corona discharge charges are accumulated at the interface.These charges create sufficiently large internal local field where polarization of dioxide zirconia nanoparticles occurs. The values of the local electric field promoting the polarization of ZrO2 nanoparticles were calculated. It was found that these values are correlated with the quantity of the surface charge density measured by the induction methods. The activation energy of maximum being responsible for a cross-border charge varies in the range of 0,84–1,1eV. By calculations it was found that the thickness of the interfacial layer increaseswith concentration of dioxide zirconia in polypropylene and receives its maximum value at concentrations of 5%.

PP + Fe3O4 nanocomposite films were produced by two technological ways, namely hot pressing and extrusion techniques. It was found that depending on the production methods, the proportion of absorbed EM waves by the composite films differs. It is known that the EM waves absorbing properties of materials depend on the electrophysical parameters. Therefore, the frequency dependence of dielectric permittivity and dielectric loss were investigated for both type samples. The polarization properties and the frequency dependence of the dielectric losses of the nanocomposites obtained by different methods vary both quantitatively and qualitatively. It was also studied the influence of an external permanent magnetic field on the electrical resistivity of the nanocomposite samples. It was found that independent of the production techniques the electric resistivity of both polymer nanocomposite samples decreases under the influence of an external magnetic field, and the negative magnetoresistive effect was observed. The proportions of EM waves absorption and also differentiation of other electrophysical properties of these nanocomposites, which consist on same components but were produced throughout different methods, could be explained by the fact that the diamagnetic anisotropy, defects density and also interphase layer on the boundary of nanoparticles and matrix in these materials are quite different from each other.

The tendency to improve the properties of insulating materials by incorporating inorganic nanoparticles has become necessary in order to design new insulation systems. In this study, PVC/TiO2-based nanocomposites with different loadings (3, 5 and 10 wt.%) of TiO2 nanoparticles were prepared by the solution mixing method. The morphology of the prepared nanocomposites was studied by Atomic Force Microscope (AFM). Experimentally, it was found that as the concentration increases, the size of the surface structural elements and particle size increases. Photoluminescence (PL) analysis of samples shows improvement compared to the pristine polymer. Furthermore, PL intensity for nanocomposites increases depending on the concentration and saturation occurs at a certain amount of titanium dioxide nanoparticles. The increase in luminescence intensity till a certain nanoparticle content is due to the growth of the luminescent surface area. Further saturation is explained by the increase in particle size with no increase or a slight reduction in surface area. Dielectric properties of nanocomposites were studied. It was found that dielectric permittivity of the materials increases as the nanoparticle volume content increases and it reaches at its highest value for the nanocomposites with 3% nanoparticle content. The optical properties of the polymer and nanocomposite films were studied in the region 200 nm to 600 nm. It was found that the PVC/TiO2 nanocomposites showed enhancement in the absorbance intensities which was more significant for the nanocomposites with higher nanoparticle content compared to the pristine polymer. Furthermore, absorption spectra were used to calculate the optical bandgap of the prepared nanocomposite films and redshift observed in the calculated values of bandgap for nanocomposites. Consequently, it was proved that by incorporating TiO2 nanoparticles into the polymer matrix, the spectral region of the samples can be expanded resulting in broadened application of such systems in various fields of science and technology.

This paper deals with an investigation on the photoluminescence (PL) properties of PP+PbS/CdS nanocomposites at different temperatures ([Formula: see text], [Formula: see text] and [Formula: see text]) under vacuum. The optical bandgap was calculated on the basis of the spectra of UV absorption and it was shown that after thermal treatment the nanocomposites optical bandgap changed. The change has been attributed to the modification of the upper molecular structure of the polymer matrix due to the thermal process. The luminescence spectra of nanocomposites before and after thermal treatment at different temperatures ([Formula: see text], [Formula: see text] and [Formula: see text]) under vacuum were also measured and discussed. A very high luminescence intensity was observed after thermal treatment at [Formula: see text] temperature. This was attributed to the luminescent centers’ increase and the optimal structure formation.

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.

In the present study we had an aim to develop the methods of functionalizing the surface of magnetite nanoparticles with cefotaxime and ceftriaxone antibiotics. The quantitative analysis of the nanostructured cephalosporins was determined by Atom Absorbance Spectroscopy (AAS) and based on the Lambert-Beer law. The engineered nanostructures were tested on gram-negative microorganisms Klebsiella spp., of Enterobacteriaceae, and gram-positive bacteria Staphylococcus aureus, each having multi-drug resistance properties.

The structures and magnetic properties of the PP[Formula: see text]+[Formula: see text]Fe3O4 nanocomposites manufactured by different technological techniques were studied in this work. Polymeric nanocomposite materials based on PP[Formula: see text]+[Formula: see text]Fe3O4 were obtained by two technological methods: hot pressing and extrusion. Scanning electron microscopy (SEM) and AFM investigations of nanocomposites were carried out for structure analysis. It was found that the distribution of Fe3O4 nanoparticles in the polymer matrix for nanocomposites obtained by the hot pressing method is uniform and monodisperse. Compared to this, the heterogeneous and inhomogeneous distribution of nanoparticles in the polymer matrix for the samples that were produced through extrusion method was observed. Furthermore, the nanocomposite samples produced via the extraction method have a lower surface regularity rather than those obtained by hot pressing. M(H) and M(T) studies of polymer nanocomposite samples synthesized through both technological methods were performed. Studies have shown that for relatively low concentrated samples — PP[Formula: see text]+[Formula: see text]10% Fe3O4, the values of the saturation magnetization were close, but the magnetization of nanocomposites obtained by heat pressing was slightly higher than the other samples. This is because the samples obtained by hot pressing method are characterized by higher uniformity and structure that is called “flat packaging”.

New nanocomposite structures based on isotactic polypropylene and zirconia nanoparticles are developed; the distribution of the zirconia nanoparticles is studied by optical (Motic AE 30/31) and scanning electron microscopy (Carl Zeiss). It is shown that, during the direct introduction of nanopowders into the polymer matrix, the powder nanoparticles form cluster-like fractal structures in the form of dendrites even at the first stage of mixing of the components. The electron microscopy study of the samples shows that the developed technique for preparing nanocomposites makes it possible to obtain a homogeneous distribution of zirconia nanoparticles in the matrix of polypropylene. The dielectric characteristics of nanocomposites based on polypropylene and zirconia are studied. It is found that the dielectric permeability in PP + ZrO2 nanocomposites varies as a function of the frequency owing to the low-frequency polarization.

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 e, 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.

In this paper, we present the synthesis of nanostructures of magnetite nanoparticles (NPs) with ciprofloxacin and kanamycin antibiotics, based on self-assembling principle. The nanostructures were prepared in crystallite size, ranging 8–16 nm, in one pot addition setup and further washing steps, using only iron precursors and above-mentioned antibiotics as stabilizers. Nanostructures were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis methods, Fourier transform infrared (FTIR) and ultraviolet (UV) spectroscopy methods. It was found that they have well-shaped spherical form and are homogeneous in size. The quantitative analysis of nanostructured antibiotics was performed by atom absorbance spectroscopy (AAS) as well as on the basis of Lambert–Beer law. Prepared nanostructures were tested on Staphylococcus aureus and Pseudomonas aeruginosa. Obtained results demonstrated that these nanostructures are able to improve antimicrobial properties and decrease the minimal inhibitory concentration (MIC) of pristine kanamycin and ciprofloxacin antibiotics.

The present work is devoted to preparation of track membranes by irradiation of polymeric film of isotactic Polypropylene (PP) with accelerated heavy ions of xenon (energy 1.3 MeV/nucl, flow density 10 8 up to 10 10 ion/sm 2 ). The further chemical treatment of irradiated film with KOH (Potassium Hydroxide) solution leads to formation of pores in the polymeric film. It was found that the optimal conditions of track etching of heavy ions in polymer have been studied by the process of pores etching in polymeric film by Atomic Force Microscopy (AFM) method. It has been found out by AFM method, that increase of Xe ions beam density from 10 8 up to 10 10 ion/sm 2 leads to increasing of number, diameter and depth of pores on the surface and from within of polypropylene film. The influence of alkali concentration and temperature on size and depth of pores in the polymeric film has been detected. It has been shown that increasing of concentration of alkali 0.25 M up to 1.5 M and temperature up to 80 ° С lead to decreasing of diameter and depth of pores in polypropylene matrix.