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In the given paper were investigated photoluminescence properties of PVDF/PbS/CdS hybrid nanocomposites after thermal treatment at different temperatures (100 °C, 120 °C and 140 °C) under the vacuu...

In this study, the influence of electro-thermo-polarization (ETP) on the charge state and luminescence properties of polymer nanocomposites based on PP and nanoparticles of amorphous silicon dioxid...

This paper deals with the investigation of electric, mechanical strength variations as well as the charge density of isotactic polypropylene (PP) and ZrO2 nanoparticles obtained in various supramol...

There have been investigated dielectric properties of PP + ZrO2 based nanocomposites after exposure to an external electric field. It is shown that before E = 10 ·106 kV/m the dielectric constant (...

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

Inorganic filler and polymer matrix based PP + SiO2 nanocomposites have been prepared by the hot pressing method. The scanning electron microscopy (SEM) and X-ray diffractometer(XRD) were used for ...

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.

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.

The effect of submicron ferroelectric BaTiO3 particles on the dielectric and electro-optical properties of the smectic-A liquid crystal (LC) with a high negative dielectric anisotropy is investigated. It is shown that the addition of BaTiO3 particles with a weight amount of 1% reduces insignificantly the transverse dielectric permittivity component e⊥ of, but significantly increases the longitudinal dielectric permittivity component e// of the smectic-A LC. As a result, the anisotropy of the dielectric permittivity Δe = e// − e⊥ of the smectic-A LC decreases. The addition of BaTiO3 particles shifts the dispersion e⊥ toward lower frequencies. Both components of the electrical conductivity of LC colloid + BaTiO3 are an order of magnitude higher than of the pure LC. The threshold voltage of the homeotropic-planar transition of the colloid is twice smaller, and its velocity is 6 times higher in comparison with the pure LC. A simple model explaining qualitatively all results obtained is presented.

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%.

The objective of the present study was to develop carboxymethyl starch (CMS) and dextran sulfate (DS) hydrogels that are able to efficiently encapsulate 5-,10-,15-,20-tetrakis(meso-hydroxyphenyl)porphyrin (mTHPP), a porphyrin-based PS agent. The study showed that the lifetime of the triplet state for porphyrin PS is significantly increase when encapsulate into hydrogel. In addition to the possible enhancement of ¹O₂ generation, other advantages to incorporating porphyrin-based PS agents into hydrogel include the ability to solubilize these generally hydrophobic agents, the small and uniform size of hydrogels, and potential for passive targeting of solid tumors via the enhanced permeation and retention effect decreasing systemic photosensitization. This novel type of carboxymethyl starch (CMS) hydrogel using dextran sulfate (DS) as a polyanionic polymer was developed to achieve complex coacervation for the incorporation and controlled release of an anti-angiogenesis hexapeptide, this was the first report describing the use of DS to formulate CMS based hydrogels.

The purpose of this review is to discuss and summarize some of the interesting findings and applications of modified chitosan (MCS) and their derivatives in different areas of drug delivery. This review highlights the important applications of MCS in the design of various novel delivery systems like liposomes, microspheres, microcapsules, and nanoparticles. In addition to their well-known effects on drug solubility and dissolution, bioavailability, safety, and stability, their uses as recipients in drug formulation are also discussed. This review also focuses on various factors influencing inclusion complex formation because an understanding of the same is necessary for proper handling of these versatile materials. Some important considerations in selecting MCS in drug formulation such as their commercial availability, regulatory status, and patent status are also summarized.

A novel drug delivery system for the treatment of brain tumors was formulated by methotrexate (MTX)-loaded polymeric nanoparticles (NPs) based on Glycol chitosan (GCS) and Dextran sulfate (DS). The physicochemical properties of resulting particles were investigated, evidencing the contribution of these nanoparticles for brain targeting. In vitro release of MTX was also evaluated. The GCS-DS nanoparticles have been developed based on the modulation of ratio show promise as a system for controlled delivery of the drug to the brain.

Hybrid materials, which consist of organic–inorganic materials, are of profound interest owing to their unexpected synergistically derived properties. Aluminium oxide (Al2O3) nanoparticles/polymer composites have been produced using a one-system polymer synthesis. The linear polymer, poly(methyl methacrylate) (PMMA, MW = 15,000 g/mol) and polymethacrylic acid (PMAA) are applied for the stabilization of Al2O3 nanoparticles. The Fourier transfer infrared (FT-IR) analysis data and scanning electron microscopy (SEM) image reveal that the core shell structure of Al2O3/PMMA/PMAA nanocomposites have been synthesized. The ratio of concentration of the capping polymer material to the concentration of the Al2O3 precursor could control the size of Al2O3 nanoparticles. With specific concentration of the reductant, the core–shell nanostructure could be fluctuated in order.

Magnetic nanoparticles in five plant species growing on the Apsheron peninsula have been detected by the EPR method. The EPR spectra of these nanoparticles proved to be similar to those of synthesized magnetic nanoparticles. The result demonstrated that plants are capable of absorbing magnetic nanoparticles from the soil. The accumulation of nanoparticles in plants is confirmed by the presence of a broad EPR signal whose maximum position of the low-field component changes from g = 2.38 and half-width of the signal of 32 mT at room temperature to g = 2.71 and 50–55 mT at 80 K. The intensity of the broad EPR signal for plants grown in radioactively contaminated areas (170‐220 μR/h) was substantially lower compared with plants grown on clean soil. The parameters of the broad EPR signal and its dependence on the temperature of recording were identical with those for synthetic magnetic nanoparticles. The photosynthetic activity and changes in the genome of irradiated plants by the analysis of PCR products were studied.

The purpose of this study was to examine chitosan (CS)-carboxymethyl starch (CMS) nanoparticles as drug delivery system to the colon. The 5-aminosalicylic acid (5-ASA) was chosen as model drug molecule. CS-CMS nanoparticles were formulated by a complex coacervation process under mild conditions. The influence of process variables, including the two ionic polymers, on particle size, and nanoparticles entrapment of 5-ASA was studied. In vitro release of 5-ASA was also evaluated, and the integrity of 5-ASA in the release fraction was assessed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The release of 5-ASA from nanoparticle was based on the ion-exchange mechanism. The CS-CMS nanoparticles developed based on the modulation of ratio show promise as a system for controlled delivery of drug to the colon.

More stringent requirements for reducing the content of aromatics have brought increasing attention to new catalysts involved in hydrotreating process. The dependence of the 2,4-dinitrotoluene hydr...

In situ polymerization of aniline was carried out of superparamagnetic (Fe3O4) nanoparticles to synthesize the middle molecular weight HCl-doped polyaniline/polyanitroaniline nanocomposites. The HCl-polyaniline/ polyanitroaniline/Fe3O4 nanocomposites have been synthesized with certain composition of Fe3O4 in the composite. Thus, the synthesized composites have been characterized by infrared spectroscopy and X-ray diffraction. The morphology of these nanocomposites was studied by scanning electron microscopy. Further, the conductivity properties have been investigated in the frequency dependence of conductivity. The presence of polarons and bipolarons is made responsible for frequency dependence of conductivity. Cole—Cole plots indicate clear shift in the distribution of relaxation times as the wt% of Fe3O4 in the polymeric matrix changes. These nanocomposites show almost symmetric semicircles of Cole—Cole plots indicating the Debye-type relaxation in their polarization response.

The main aim of this research was to develop and evaluate a multiparticulate system of Ac-poly(amidoamine)(PAMAM)(G4)-chitosan (CS) hydrogels exploiting pH-sensitive and specific biodegradability properties for colon-targeted delivery of 5-aminosalicylic acid (5-ASA). All formulations were evaluated for particle size, encapsulation efficiency, swellability, and in vitro drug release. The size of the hydrogel was found to nanorange. The integrity of 5-ASA in the release fraction was assessed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The CS-Ac-PAMAM hydrogel was developed based on the modulation of ratio show promise as a system for controlled delivery of drug.

Highly branched, functionalized polymers have the potential to act as efficient drug carrier systems. The aromatic polyether dendrimers are spherical, highly ordered, multibranched, nanometre-sized macromolecules having positively charged ether groups on the surface under physiological conditions. In this study, we have synthesized a kind of dendrimer/poly(2-hydroxy ethyl methacrylate) nanocomposite/5-aminosalicylic acid (5-ASA) for oral drug delivery. The aromatic polyether dendrimer (generation 2, hyperbranched polyether with -CH2OH functionality, 3,5-Dihydroxybenzoic acid core) was prepared from generation 2, hyperbranched polyether dendrimer with -COOCH3 form in excellent yield. FT-IR, 1H-NMR and DSC studies suggest that the monomer predominantly forms a complex with polyether dendrimers because of the interaction between the –CH2OH end groups of dendrimer and the –OH group of 2-hydroxyethyl methacrylate monomer.

The main objective of this research is to design a new extended release multiparticulate delivery system by incorporation into nanoparticles made of chitosan-polymethacrylic acid copolymers. As the first part of a continued research on conversion of chitosan to useful biopolymer-based materials, by grafting polymethacrylic acid (PMAA), free radical graft copolymerization was carried out at 70 °C, with bis-acrylamide as a cross-linking agent and persulfate as an initiator. Equilibrium swelling studies were carried out in enzyme-free simulated gastric and intestinal fluids. Also, the paclitaxel as a model drug was entrapped in these nano-gels and in vitro release profiles were established separately in both enzyme-free SGF and SIF. The drug release was found to be faster in SIF.

Ionisation chambers are the most practical and important radiation measurement devices due to their high sensitivity and relatively constant response with wide range of applied potential. In this work, a new plane-parallel ionisation chamber is proposed using carbon nanotubes as sensing electrodes. Some characteristics of the new chamber such as cable effect, leakage current and reproducibility are investigated. The polarisation effects, besides voltage effect and linearity are also verified. All tests are performed using a 60Co gamma radiation source. The obtained results are compared with that of a standard ionisation chamber (PTW Roos W34001 plane-parallel ion chamber) and international code of practice on dosimetry (i.e. IAEA TRS No. 381).

The structure and properties of nanocomposites based on zinc sulfide and poly(vinylidene fluoride) were studied. The nanocomposite material was prepared by the matrix isolation technique: ZnS nanoparticles are formed by chemical reactions in a poly(vinylidene fluoride) powder of particle size 0.5–1.0 μm.

The main aim of this research is to design a new extended release gastroretentive multiparticulate delivery system by incorporation of the hydrogel beads made of chitosan. As the first part of a continued research on conversion of N-sulfonato-N,O-carboxymethylchitosan(NOCCS) to useful biopolymer-based materials, large numbers of carboxylic functional groups were introduced onto NOCCS by grafting with polymethacrylic acid (PMAA). The free radical graft copolymerization was carried out at 70 °C, bis-acrylamide as a cross-linking agent and persulfate as an initiator. The equilibrium swelling studies were carried out in enzyme-free simulated gastric and intestinal fluids (SGF and SIF, respectively). Also, the satranidazole as a model drug was entrapped in nano-gels and in vitro release profiles were established separately in both enzyme-free SGF and SIF. The drug release was found to be faster in SIF. The drug-release profiles indicate that the drug release depends on their degree of swelling and cross-linking.

The purpose of this study was to examine chitosan (CS)–dextran sulfate (DS) nanoparticles coated iron oxide as drug carriers detectable using magnetic resonance imaging (MRI) technique. The 5-aminosalicylic acid (5-ASA) was chosen as model drug molecule. CS–DS hydrogels were formulated by a complex coacervation process under mild conditions. The influence of process variables, including the two ionic polymers, on particle size, and hydrogel entrapment of 5-ASA was studied. The in vitro release of 5-ASA were also evaluated, and the integrity of 5-ASA in the release fraction was assessed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The release of 5-ASA from hydrogel was based on the ion-exchange mechanism. The CS–DS hydrogel developed based on the modulation of ratio show promise as a system for controlled delivery of drug detectable using magnetic resonance imaging (MRI) technique.

A new synthetic macromolecule, aminodextran-coated iron oxide nanoparticles, was synthesized as drug carrier detectable using magnetic resonance imaging (MRI) technique. The synthesis process starts with a 2-step reaction that attaches a high density of amino groups to a dextran backbone. These macromolecules were coated with magnetic iron oxide molecules by a chemical reaction that can carry several molecules such as drug and peptides. The aminodextran-coated iron oxide nanoparticles thus synthesized have been characterized by Fourier infrared (FT-IR) spectroscopy. Also, the morphology of this synthetic macromolecule was studied by scanning electron microscopy.

Electrorheological fluids are new materials with good properties such as dielectric constant, dielectric loss or conductivity. These materials find practical applications in various industries. In this paper have been studied a ternary nanocomposite as rheological fluid based on Carboxymethyl starch and dimethylsulfoxide with feldspar particles. These nano composite was prepared by the two-step composite method. Firstly, the polar DMSO compound was directly intercalated into the interlayer of nano ferric oxide and then the intercalated complex was composite with CMS by the solution method. The composites, thus synthesized have been characterized by Fourier transfer infrared (FT-IR) spectrophotometer and X-ray diffraction. The morphology of these composites was studied by scanning electron microscopy.

Magnetic nanoparticles have been proposed for use as biomedical purposes to a large extent for several years. The development of techniques that could selectively deliver drug molecules to the diseased site, without a concurrent increase in its level in healthy tissues, is currently one of the most active areas of cancer research. The conjugate carboxymethyl starch (CMS)/SPIO nanoparticles were prepared by chemical reaction. Several parameters including the drug/polymer ratios in range of 1:14 were examined to optimize formulation. The size distribution and morphology of nanoparticles and in vitro release profile in phosphate buffer medium (pH 7.4) during 12 h were then investigated. The magnetic NPs prepared in this study were spherical with a relatively mono-dispersed size distribution. The conjugate carboxymethyl starch (CMS)/SPIO nanoparticles were exhaustively studied as controlled-release systems for parenteral administration of a model drug 5-aminosalicyclic acid (mesalamine) and analyzed using various release kinetic studies.

In this paper, preparation and characterization of superparamagnetic nanoparticles and their polymer composites prepared by varing doping level of conducting polymer and their microwave absorption studies at radar system in 8–12 GHz frequency range have been discussed. These composites are conducting polymers have been widely used because of their lower density as well their good environmental stability as in the case of polyaniline (PAN). In the present work, in situ polymerization of aniline was carried out in the presence of 30 mole% Fe3O4 nanoparticles to synthesize polyaniline/Fe3O4(PAN/Fe3O4) composites in epoxy resin matrix. The composites, thus synthesized have been characterized by infrared (IR) spectroscopy and X-ray diffraction. The morphology of these composites was studied by scanning electron microscopy. The measurement of % absorption was carried out in X and K band microwave region.

Natural polymers are considered high value polymeric materials because of their potential as biocompatible materials with medical applications. The chemical modification of natural polymers by grafting has received considerable attention in recent years because of the wide variety of monomers available. As the first part of a continued research on conversion of carboxymethyl starch (CMS) to useful biopolymer-based materials, large numbers of carboxylic functional groups were introduced onto CMS by grafting with polymethacrylic acid (PMAA). Free radical graft copolymerization was carried out at 70 °C, bis-acrylamide as a crosslinking agent and persulfate as an initiator. Equilibrium swelling studies were carried out in enzyme-free simulated gastric and intestinal fluids (SGF and SIF, respectively). Also, the sodium dicofenac as a model drug was entrapped in these nano-gels and the in vitro release profiles were established separately in both enzyme-free SGF and SIF. The drug release was found to be faster in SIF. The drug-release profiles indicate that amount drug release depends on their degree of swelling, and crosslinking. This hydrogel converted to nano by freeze-drying method and characterized by scanning electron microscopy, differential scanning calorimetry and FT-IR spectrometry.

The main aim of this research is to study the in vitro photocytotoxicity and cellular uptake of biodegradable polymeric nanoparticles loaded with photosensitizer mTHPP. As the first part of a continued research on conversion of N-sulfonato-N,O-carboxymethylchitosan (NOCCS) to useful biopolymer-based materials, large numbers of carboxylic functional groups were introduced onto NOCCS by grafting with polymethacrylic acid (PMAA). The free radical graft copolymerization was carried out at 70°C, bis-acrylamide as a cross-linking agent and persulfate as an initiator. These results show that the nanoparticles have high loading capacity and stability. These nanoparticles are suitable as carriers for photodynamic therapy in vivo.