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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]

Copyright of Nuclear Physics & Atomic Energy is the property of National Academy of Sciences of Ukraine, Institute for Nuclear Research 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.)

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.)

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]