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Polymer/inorganic hybrid based on silica sol and grafted polyacrylamide chains (SiO2/PAAm) was obtained by radical graft polymerization of acrylamide "from" unmodified silica surface. Its main parameters: RavSiO2, MvPAAm and N (the number of grafts per inorganic particle) were determined using static light scattering, elemental analysis, DTGA and viscometry. The hybrid was used as effective matrix in synthesis of NiNPs by borohydride reduction of Ni2+-ions in aqueous medium. A special approach to characterizing the kinetics and efficiency of NiNPs formation in pure water and hybrid solutions using UV-Vis spectroscopy was proposed and implemented. Due to this, an increase in the rate of accumulation and yield of NiNPs both in pure water and hybrid solutions with an increase in the Ni-salt concentration was established. In addition, a decrease in this rate with an increase in the concentration of hybrid matrices was found, as well as a slowdown in the reduction reaction in hybrid solutions compared to pure water. It was shown by TEM that the separate structural elements of the NiNPs/hybrid compositions are the swollen "hairy-type" hybrid structures with a size of ∼8.0–49.2 nm containing small (∼1.0–5.4 nm) NiNPs in PAAm "coronas." [ABSTRACT FROM AUTHOR]

Polymeric nanocomposites containing nanodiamonds are attractive multifunctional materials with a growing range of applications. Since the microstructure of the system determines its properties, it is an important task to establish the features of structure formation of nanodiamonds in the polymer matrix. The structural features of nanocomposites based on polyethylene glycol (PEG) and ultradispersed nanodiamonds (UDNDs) were investigated using the methods of wide-angle and small-angle X-ray scattering. Systems based on nanodiamonds of detonation synthesis and crystalline PEG were prepared by ultrasonic dispersion in melt. The studied UDNDs are found to be polydispersed particles with a narrow size distribution. The average radius of the UDNDs primary particles is 20 nm. It is shown that as the content of nanodiamonds in the system increases, the aggregation processes increase. The structure of such systems is well described within the model with multilevel fractal aggregation. Fractal analysis identified the type of fractal aggregates of each structural level and determined their sizes. Depending on the content of the filler in the system, particles of UDNDs form different types of aggregates. At low filler content, dense mass fractal aggregates and surface aggregates with a smooth surface are formed. At high contents, dense aggregates of surface-fractal type with a rough surface are formed. It is established that aggregates with an average size of 60-75 nm are formed at the first structural level, and aggregates with an average size of 225-240 nm are formed at the second level. [ABSTRACT FROM AUTHOR]

The paper is devoted to the investigation of the physical properties of graphite nanoplatelets / epoxy composite materials with a modified level of interface interaction due to pre-irradiation of the filler with ultraviolet light. The influence of interface interaction at the filler / matrix interface in polymer-carbon composite materials on their electrodynamic properties is determined, which is the basis for the development of composite materials with an adjustable set of physical properties. By analyzing within the model, which takes into account the volume fraction of the interface region, it has been shown that the increase of dielectric constant in composites, where pre-irradiated with ultraviolet light graphite nanoplatelets were used as a filler, occurs due to an increase of the dielectric constant of the interface layer, which is associated with a change in the chemical composition of the surface of graphite nanoplatelets. [ABSTRACT FROM AUTHOR]

The dynamics of atoms and molecules in gel electrolyte based on polyvinyl chloride and a solution of LiClO4 in propylene carbonate was studied by the method of quasielastic scattering of slow neutrons. The coefficients of selfdiffusion of atoms and molecules are determined and a possible variant of the mechanism of charge transport in this system is proposed. [ABSTRACT FROM AUTHOR]

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Copyright of Journal of Nano- & Electronic Physics is the property of Sumy State University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Research into the microstructure, electric and dielectric properties of the systems based on polyethylene glycol and multiwalled carbon nanotubes (MWCNTs), which were functionalized by different methods is done using the methods of impedance spectroscopy and optical microscopy. It is determined that the probed systems show the percolation behavior. It is discovered that when using of OH-functionalized MWCNTs, the percolation threshold of conductivity is increased from 0.44% to 0.55%, and using H2O-functionalized MWCNTs, the percolation threshold of conductivity is increased to 3%. It is determined that the percolation threshold of dielectric permittivity considerably increases when functionalized MWCNTs are used. [ABSTRACT FROM AUTHOR]

With recourse to phonon-phonon interaction, and also macromolecular kinetics, under the action of an ultrasonic field of 0.4 MHz frequency, an analysis has been made of the energy dissipation in modified polyvinyl chloride. The area of possible use of PVC composites is indicated. [ABSTRACT FROM AUTHOR]

The research of electric properties of the systems based on polyethylene glycol and carbon nanotubes (CNT) near-by the percolation threshold is done using the method of impedance spectroscopy. It is set that the percolation threshold for these systems substantially depends on the sizes of nanotubes. It is discovered that with the increase in the CNT diameter, the percolation threshold is increased. The dispersion parameters of nanotubes were calculated using theoretical model. The results of calculations and microphotographs testify to the high level of CNT aggregates in the polymer nano-composites based on polyethylene glycol. [ABSTRACT FROM AUTHOR]

By using impedance spectroscopy and optical microscopy methods the investigation of electrical properties of systems based on polypropylene glycol was conducted. It was shown that adding exfoliated layered fillers to the system shifts percolation threshold to low concentration of nanotubes. Analysis of critical indexes of conductivity for investigated systems has shown that such low values of t (1,19-1,43) mean that the formation of conductive network because of strong interaction between laponite and single nanotubes is not a statistic percolation process and distribution of filler particles is nonuniform. Thus, incorporation of third component leads to significant change of percolation properties of filled system, because of its strong interaction with conductive particles. Moreover, insertion of third component leads to significant enhancement of distribution of nanotubes in the bulk of polymer matrix and can improve a number of properties of system filled with nanosized particles polymers. [ABSTRACT FROM AUTHOR]

The research of the electrical properties of the systems based on polyethylene glycol and carbon nanotubes near-by the percolation threshold is done using the method of impedance spectroscopy. It is established that the percolation threshold for these systems is 0,5%, and critical index t = 1,17. It is discovered that non-conducting polymeric film appears between separate nanotubes. The thickness of the film which is 7-8 Å and its contact resistance which is 3·105 Ohm were derived using theoretical models. This explains a difference in conductivity of pure nanotubes and probed system after the percolation threshold. [ABSTRACT FROM AUTHOR]

The investigation of electric and dielectric properties of the systems based on polypropylene glycol and carbon nanotubes, which contain inorganic salt LiClO4 and without salt, was conducted using the method of impedance spectroscopy. It was discovered that these systems show a fractal behavior. The percolation thresholds of the probed systems is determined, it is 0.45% and 0.40%, accordingly. It was set that the processes of charges transfer are described well within the framework of the model of intercluster polarization. For the system PPG-LiClO4- CNT the so-called, "bridge" effect takes place which leads to the decrease of the prcolating threshold. [ABSTRACT FROM AUTHOR]

Peculiarities of formation kinetics of sequential semi-interpenetrating polymer networks (IPNs) based on polyurethanes with different crosslink densities and linear polystyrene, poly(butyl methacrylate), and poly(methacrylic acid) have been studied. The molecular-mass distributions of linear polymers developed in semi-IPNs are examined by size-exclusion chromatography. Viscoelastic and thermophysical properties of sequential semi-IPNs were investigated by the method of dynamic mechanical analysis and differential scanning calorimetry. The experimental data show the dependence of the kinetic parameters of polymerization and relaxation properties on Mc. As a result, the material structure may change in a wide range from a nearly single-phase system to a two-phase one. Small angle X-ray scattering measurements indicate that there is symbate dependence between the degree of segregation of components of sequential semi- IPNs and their microheterogeneous structure on the internetwork space. Two hierarchical heterogeneity levels are found to exist in polymer networks, and the features of each of these levels are analyzed. [ABSTRACT FROM AUTHOR]

The development, structure and properties of polymer electrolytes were discussed in the review. The special attention was spared to the influence of fillers on structural descriptions, electric and thermophysical properties of nanocomposite polymer electrolytes. The data of conductivity and temperatures of transitions for the described systems were cited. [ABSTRACT FROM AUTHOR]

By using Fuoss-Kraus theory and the conductivity data, we study the ion association in polymer electrolyte based on polyethyleneglycol, lithium perchlorate and carbon nanotubes. We also determine that the filler addition decreases the aggregation in the polymer electrolyte, which leads to the increase in the number of free ions, as well as to the conductivity growth. [ABSTRACT FROM AUTHOR]

Effect of carbon nanotubes (CNT) on the enthalpy relaxation of polystyrene (PC) was avaluated from calorimetric studies. The apparent activation energy and characteristic relaxation times of the nanocomposites (NC) were lower than that of the neat PC. It is postulated that the decrease of this parameteres had resulted from the increase in the mobilities of the PC molecules and free volumes in the NC, which were supported by the decreased glass transition temperatures of the nanocomposites compared to the neat PC. [ABSTRACT FROM AUTHOR]

Thermophysical and dielectric properties sequential semiinterpenetrating polymer networks (semi-IPNs) based on hydrophilic polyurethanes (PU), differing MM of oligomers, and natural polymers (gelatin, carboxymethyl cellulose) were investigated by methods DSC and DRC. It has been established, that with increase Mc initial PU networks the content of a linear component in compose of IPNs increases. The degree of crystallinity κpucmaππuɥʜocmu of PU-componenst in IPNs with gelatin and carboxymethyl cellulose increases. It was show, that introduction of natural linear polymers in sequential semi-IPNs influences on thermophysical characteristics and molecular mobility of the investigated polymeric systems depending on Mc initial PU networks . [ABSTRACT FROM AUTHOR]

The morphology of the triblock copolymers (TBC) containing chemically complementary poly(ethylene oxide) (MvPEO = 3 · 103 ÷ 1 · 105) and polyacrylamide (MPAAm = 4.5 · 104 ÷ 9.07 · 105) of different chain lengths is studied. The loss of the PEO ability to crystallize in TBC at MvPEO ≤ 4 · 104 is established. At the same time, PEO blocks with Mv = 1 · 105 form small crystalline domains in the TBC structure, but their crystallinity degree turns out to be by 2.8 times less than that in individual poly(ethylene oxide). A microphase separation in amorphous regions of the TBC structure at high values of MPAAm is revealed. It is shown that the main reason for the effects observed is the formation of a complex between PEO and PAAm blocks by hydrogen bonds. [ABSTRACT FROM AUTHOR]

The relaxation properties of polymer electrolytes based on block-copolymers PEO-PPO-PEO and LiClO4 were studied. It is shown, that the concentration dependence of relaxation times of conductivity has extreme character. The influence of free volume to process of ionic transport in polymer electrolytes PEO-PPO-PEO/LiClO4 is detected. It is shown, that such systems can be referred to "fragile". [ABSTRACT FROM AUTHOR]

The structure and dielectric properties of polymer electrolytes based on block- copolymers PEO-PPOPEO and inorganic salt LiClO4 were studied. It was shown, that at the ratio of Li/I = 1:8 and more polyelectrolytes based on three block copolymers PAO-PPO-PEO/LiClO4 are completely amorphous that results in growing of ionic conductivity in the systems of such type. [ABSTRACT FROM AUTHOR]

New polymeric adsorbents based on water soluble polysaccharide konjac glucomannan cross-linked with blocked alkyl- and aryl-, di- or polyisocyanate were synthesized and used for phenol adsorption from aqueous solutions. The interaction of polysaccharide with å-caprolactam blocked isocyanates was confirmed by pyrolysis mass-spectrometry. Glycopolymers based on cross-linked konjac glucomannan demonstrate good phenol sorption ability. To describe phenol adsorption on glycopolymers Langmuir and Freundlich models were used. The influence on phenol adsorption capacity of polysaccharide hydroxyl group substitution degree, isocyanate structure as well as pH value was analyzed. Adsorption equilibrium had been reached after 24 hours contact with phenol, nevertheless, 75–80% of phenol is adsorbed during first 6–8 hours. The highest phenol adsorption capacity onto GP had been reached at neutral medium whereas adsorption capacities at acid and alkali media are slightly lower. In contrast to glycopolymers based on aliphatic diisocyatate glycopolymers based on aromatic ones show higher adsorption capacity. This indicates the important role of π–π interactions between aromatic rings of adsorbate and polymeric matrix during adsorption. [ABSTRACT FROM AUTHOR]

A promising composite material is proposed to reduce the endogenous and exogenous contamination of chicken eggs with pathogenic microflora during their formation and storage. It is based on hybrid biocompatible and biodegradable silica/ polyacrylamide nanocarriers containing small silver nanoparticles (dav=2.4±1.0 nm) that are orally administered to laying hens with drinking water. The features of the formation of nanosilver in hybrid carriers by borohydride reduction of a silver salt at its various concentrations in an aqueous solution have been studied. An interesting effect of the sharp appearance of the second surface plasmon resonance band in the UV-Vis spectra of a silver salt/hybrid mixture at a high salt concentration was found. T is was explained by sharp structural changes in the hybrid carriers caused by the simultaneous growth of many AgNPs in them. It was assumed that the intensive growth of many AgNPs in one hybrid particle was accompanied by detachment of the grafted PAAm chains from the SiO2 surface due to the breaking of hydrogen bonds. The change in the state of the composite material under the influence of the pH of the solution, the concentration of nanoparticles, the presence of NaCl (as in a "physiological solution"), and visible light was studied by UV-Vis spectroscopy, potentiometric titration, and TEM. Nanosilver in carriers showed high stability with respect to most of these factors. The influence of the composite material on the clinical state of laying hens and important parameters of their eggs and blood was studied when it was administered orally with drinking water three times every 10 days at doses of 0.2 and 0.4 mg per chicken per day. A striking effect of selective endogenous accumulation of silver in eggshells has been revealed. This confirmed the penetration of the nanosilver composite into the circulatory system of chickens by passing through the digestive tract, absorption through the intestinal epithelium and further transport into the tissues of the chickens, including the oviducts, where protein and eggshell are formed. Such penetration did not cause a toxic effect on the body of laying hens. [ABSTRACT FROM AUTHOR]

It has been studied electrical and optical properties of the systems based on the polypropylene glycol and carbon nanotubes by impedance spectroscopy and spectrophotometry methods. It is shown that conductivity grows and optical permeability decreases with nanotubes content at the system according to the percolation behavior. The concentration dependences of the conductivity and optical permeability have been analyzed within scaling approach. It is shown that optical percolation threshold for this system equals 0,01%. The experimental results have described within critical percolation model. [ABSTRACT FROM AUTHOR]

By method of impedance spectroscopy the dielectric properties of polypropylene glycol with Mw=400 (PPG-400) and carbon nanotubes(CNT) in percolation transition field were investigated. At the defined concentration CNT ~0.45% in the PPG-400/CNT system the percolation threshold was observed and both sharp change of electrical conductance and α-relaxation time was appeared. [ABSTRACT FROM AUTHOR]

Structure and conductivity of systems based on polyethyleneglycol (PEG), LiClO4 and anisometric nanofillers in bulk and thin films were studied using X-ray scattering and dielectric relaxation spectroscopy methods. It was shown, that structure of the systems based on PEG, substantially depend on the content of the nanofiller and the type of the plate, where the film was formed. It is discovered that the relative degree of crystallinity of PEG/LiClO4 has extreme behavior, which is dependent on the content of the nanofiller. [ABSTRACT FROM AUTHOR]

The relaxation processes and conductivity of organic-inorganic systems based on polyethylene glycol and polyhedral silsesquioxane (POSS) were studied using dielectric relaxation spectroscopy. It is shown that the levels of conductivity of the systems based on POSS substantially depend on the amount of ion groups and content of inorganic phase. It is discovered that conductivity of direct current has extreme dependence on composition of organic-inorganic hybrid systems based on POSS. The structure was studied by small angle x-ray scattering. The results of x-ray scattering were analyzed using classical and fractal formalism. The structure of organic-inorganic nanocomposites based on POSS has the extremal nature. [ABSTRACT FROM AUTHOR]

A graft copolymer of poly(vinyl alcohol) and polyacrylamide (PVA-g-PAAm) with interacting main and graft ed chains was synthesized by radical matrix polymerization of PAAm from the PVA backbone in an aqueous medium. Its basic molecular parameters including the number and length (molecular weight) of graft s were determined using elemental analysis, DTGA and viscometry. The copolymer macromolecules formed special monomolecular micelles of elipsoidal shape and length ~18-64 nm in aqueous solutions due to the formation of intramolecular polycomplexes between the main and graft ed chains. This copolymer was used as a hydrophilic matrix for the in situ synthesis of nickel nanoparticles (NiNPs) in aqueous solutions. On the basis of UV-Vis spectroscopy, an original and simple method for monitoring the kinetics of the formation and yield of metal nanoparticles in systems in which a surface plasmon resonance band does not appear has been proposed and implemented. Using this approach, the kinetics of borohydride reduction of Ni-salt to NiNPs in pure water and PVA-g-PAAm solutions was studied depending on the concentrations of Ni-salt and copolymer matrices. An increase in the initial rate of accumulation and yield of NiNPs with an increase in the concentration of Ni-salt and a decrease in both parameters in copolymer solutions in comparison with pure water was established. At the same time, the accumulation rate and NiNP yield in a complex way was depended on the matrix concentration that was determined by the ratio of such factors as a decrease in the diffusion rate of NaBH4 molecules in copolymer solutions and the accumulation of Ni2+-ions in matrix particles due to complexation with active chemical groups at the first stage of reduction process. The morphology and main structural elements of the NiNPs/PVA-g-PAAm composition were revealed using TEM. It was shown that the in situ synthesis of NiNPs in copolymer matrices was accompanied by the "detachment" of PAAm graft s from the main PVA chains and led to the appearance of two new structures, such as "hairy coils" and "hairy rods", containing small spherical NiNPs (d~0,5-12,0 nm) in isolated and chain states, respectively. The appearance of the latter structures was explained by the formation of coordination complexes of Ni2+-ions with active groups of both PVA and PAAm chains at the first stage of the reduction reaction. [ABSTRACT FROM AUTHOR]