Dusko Dudic

University of Belgrade · Vinca Institute of Nuclear Science

The most important characteristics of stationary battery installations are environmental friendliness and low price. Therefore, widely available and acceptable materials such as zeolite should be the focus of research in this field of science. The properties of a simple system consisting of graphite electrodes and zeolite/water/NaCl/MgCl2 electroly...

Barium titanate (BT) perovskite particles were surface modified by means of mechanical treatment and used as inorganic component in polyvinylidene fluoride (PVDF) based composites. The changes in electrical properties of the composite films with increasing in filler content were followed by dielectric spectroscopy, breakdown strength and D-E measur...

This article reports on photodielectric properties of hydrocolloids of TiO2 particles and Au/TiO2 hybrid particles of lateral dimension of ∼200 nm. Illumination of the colloids with visible light did not cause measurable changes in their electrical conductivity, while the application of UV (365 nm) light led to photoinduced increase in conductivity...

The dielectric properties of nanocomposites based on isotactic polypropylene (iPP) and atactic polystyrene (aPS) obtained by novel, simple, and environmentally friendly treatment technique have been analyzed in this study. The best treatment conditions to obtain nanocomposites with embedded core‐shell particles with enhanced dielectric properties w...

Metal–organic frameworks (MOFs) are a class of materials that are increasingly used for the detection and separation of gases. This article presents the influence of gamma radiation on the dielectric properties of a LDPE/ZIF-8 composite that can be used for the production of gas sensors and massive gas absorbers. A low-density polyethylene (LDPE)–m...

The price and environmental aspects of electricity storage significantly affect the application of green technologies. The electrochemical batteries are currently the best choice for storing electricity for most industrial needs and products. Polymer capacitors show very low energy density compared to conventional batteries and therefore cannot be...

Fluorescent nanocomposite films were prepared by solution mixing of polyvinyl alcohol (PVA) and tryptophan functionalized silver (AgTrp) nanoparticles. Synchrotron excitation deep-ultraviolet (DUV) fluorescence imaging was used to follow the distribution of AgTrp nanoparticles within the polymer matrix. Pronounced growth of dendrite-like structures...

Polymer composite films of tris‐(8‐hydroxy‐quinoline) aluminum (Alq3) and polymethyl methacrylate (PMMA) at two different concentrations were investigated. Dielectric properties of the samples were measured in broad frequency range and results show an increase in specific conductance and susceptance by adding Alq3 in PMMA. Changes in dielectric spe...

Orientation and radiation processing of polymeric materials are the main steps in certain modern technologies and have extensive applications. The properties of such treated polymers can change significantly in time and under various exploitation conditions and therefore, investigation of some specific effects of aging and storage of these systems...

Na0.25K0.25Bi0.5TiO3 (NKBT) perovskite particles are synthesized by solid-state method and used as a filler for polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) co-polymer. X-ray diffraction analysis of NKBT powders shows that the particles have a rhombohedral perovskite crystal structure (R3c symmetry). Raman spectroscopy reveals that the...

This study provides a new insight into the relationships between absorption and adsorption processes that occur during the treatment of iPP in aqueous solutions of metal-chloride salts, as well as the impact of these processes on the electrical conductivity of this nonpolar polymer. The polypropylene films (0.5 mm) were exposed to three-day treatme...

Dielectric characterization of materials in the RF domain is usually carried out on samples with applied electroconductive electrodes. A high-quality contact between a sample and the measuring electrodes provides a stable current flow through the sample and information on the exact value of the electric field in which the sample is located. It also...

In this paper, we report surface dielectric and photodielectric properties of low density polyethylene (LDPE)/Emodin composite. Emodin was extracted from Fallopia japonica plant. The composite was obtained from the xylene solution. Dielectric measurements were performed in the frequency range from 240 Hz to 4 kHz and the temperature range from 20 °...

Flexible and transparent substrate materials were fabricated by using bacterial cellulose (BC), silk fibroin protein (SF) and/or polyvinyl alcohol (PVA). The BC-SF and BC-SF-PVA films obtained were further modified by impregnation with silver nanocubes (AgNC). The influences of the silver nanocubes and white light illumination on the electric and v...

Modified cellulose materials are finding increasing application in electronics, because of the need for more environmental-friendly electronic circuits. The papers prepared from poly(ethyleneimine)–TiO2–anthocyanin-modified cellulose fibres are completely environmentally friendly and can be applied to the construction of photocells or photo-/humidi...

In this paper, a new simple and environmentally friendly treatment technique for obtaining polymer nanocomposites with appropriate dielectric properties has been presented. Sheets of isotactic polypropylene and atactic polystyrene were immersed in 3 saturated water solutions of alkali metal salts (LiCl, NaCl, and KCl) at 2 fixed temperatures (23°C...

In this paper, we report surface dielectric and photodielectric properties of low density polyethylene (LDPE)/Emodin composite. Emodin was extracted from Fallopia japonica plant. The composite was obtained from the xylene solution. Dielectric measurements were performed in the frequency range from 240 Hz to 4 kHz and the temperature range from 20 °...

Adriaan S. Luyt, et al., Dielectric sensitization of zeolitic imidazolate framework-8 (ZIF-8) nanopowder Abstract: Metallo-organic complexes are a class of materials that are increasingly used in sensory applications. Zeolitic imidazolate frameworks (ZIFs) are their subclass that are topologically isomorphic with zeolites. The porosity of the cryst...

The article describes the influence of humidity on the surface photodielectric properties of papers prepared from poly(ethyleneimine)-TiO2 nanoparticles-anthocyanin modified cellulose fibres. The anthocyanins were extracted from purple cabbage, beet-root, plum peel, red wine and red currant juice. The samples were conditioned to various relative hu...

This work reports on the effect of medium-soft M3 wax and radiation-induced crosslinking on the morphology, thermal and mechanical properties, as well as electrical conductivity and thermo-switch properties of LDPE containing different amounts of carbon black (CB) or carbon black plus zinc metal as filler. Although the filler was generally well-...

This paper reports on the presence of wax and radiation-induced crosslinking on the morphology, thermal and mechanical properties, as well as electrical conductivity and thermo-switch properties of LDPE containing different amounts of carbon black (CB) or carbon black plus zinc metal as filler. Although the filler was generally well dispersed in th...

The conversion of solar energy into electricity is in the focus of a large number of scientists. Because of the problems caused by the use of fossil fuels, the use of renewable and environmentally friendly energy sources is desirable, and in some countries the use of a certain percentage of such energy sources becomes a legal obligation. Today ther...

The aim of this study was to investigate the presence of wax, different Ag nanoparticle contents, and different cooling rates from the melt, on the morphology, thermal and electrical conductivity, and dynamic mechanical properties of iPP. The Ag particles were well dispersed in the polymer, and formed nucleation centres for the crystallization of i...

Conductive polymer composites (CPCs) based on low-density polyethylene (LDPE), high-density polyethylene (HDPE), isotactic polypropylene (iPP) and carbon black (CB) micro-particles blended with atactic polypropylene (aPP) and medium-soft paraffin wax (M3 wax) were studied. The aim of this study is to determine the effect of wax, aPP, irradiation an...

Poly(ethyleneimine)–TiO2–anthocyanin modified cellulose fiber sheets were prepared as a support material for dye-sensitized solar cells. The study is focused on the effects of different anthocyanins on the photo-induced changes and contact relaxation of the surface AC-conductivity of the papers. The anthocyanins were extracted from purple cabbage,...

The surface dielectric properties of acid etched low-density polyethylene (LDPE) were analyzed in the frequency range from 20 Hz to 200 kHz. Samples were treated with various acids for a period of one hour, at temperatures ranging from 20 to 70 °C. After the treatment, the samples were analyzed with Fourier-transform infrared spectroscopy (FTIR). T...

This study describes the possibility of dielectric characterization of the initial stages of ageing in an low-density polyethylene (LDPE) + graphite composite, which is not possible using the standard method of dielectric spectroscopy. It is shown that the differences between the delay angles, ΔΦ = ΦTRI - ΦSIN, obtained using triangular and sinusoi...

Nanocomposites of polyvinylidene fluoride/polymethyl methacrylate (PVDF/PMMA) blend and mechanically activated barium titanate (BaTiO3) particles were prepared by melt mixing. Modification of filler by means of mechanical activation has a profound effect on the crystallization of PVDF in the blend matrix. Raman analysis showed that the modified BaT...

Electrical conductivities of low-density polyethylene (LDPE)–carbon black (CB) composites were studied using high resistance meter at room temperature (DC conductivity) and dielectric spectroscopy (AC conductivity) in the frequency range between 90 kHz and 13 MHz and temperature range from 120 to 355 K. DC measurements revealed a percolation thresh...

There is currently great interest in the technological properties of conductive polymer composites because their cost-performance balance. They have a wide range of industrial applications -in anti-static materials, self regulating heaters, current overload and overheating protection devices, and materials for electromagnetic radiation shielding. M...

Electrical properties of pure epoxy and epoxy–hematite nanorod composites have been investigated. The nanorods were synthesized by the forced hydrolysis method and further mixed with epoxy to obtain the nanocomposite. TEM analysis revealed that they have an average diameter of about 8nm, with an average aspect ratio of 25. DC-conductivity and DC-cu...

The electrical conductivity of composites obtained by mixing epoxy resin and expanded graphite (EG) nanosheets has been investigated. Conductivity changes of up to 11 orders of magnitude were observed as the filler load increased from 0 to 8 wt.%, while the percolation threshold was around 3 wt.%. It was also shown that epoxy/EG composites with int...

The secondary crystallization of aged isotactic polypropylene (iPP) of different morphologies, which occurs during annealing in the vicinity of the melting temperature (140 °C), was studied using differential scanning calorimetry (DSC) and density measurements. The results of calorimetric and density measurements were correlated. Kinetics of the hi...

The process of low-melting point (LMP) a-phase formation in a quenched and annealed isotactic polypropylene (iPP) was studied by means of differential scanning calorimetry. The in¯uence of preparation conditions (quenching and annealing temperatures, annealing times and sample thickness), together with the measurement parameters (heating and coolin...

Stress relaxation at room and elevated temperatures of high density (HDPE) and linear low-density polyethylene (LLDPE) has been investigated. Viscoelastic parameters (elasticity moduli and viscosity coefficients) of amorphous and crystal fraction at temperatures 18, 40, 60, 80 and 100 °C are determined by using two-process model for stress relaxati...

Recrystallizaton processes in isotactic polypropylene (iPP) of different morphologies, which occur during accelerated ageing, were studied using differential scanning calorimetry (DSC) and density measurements. Morphology and initial crystallinity were found to have an influence on recrystallization. Differences in recrystallization behavior of iPP...

Effects of high energy radiation on stress relaxation behavior of unoriented (λ=1) and oriented (λ=9) ultrahigh molecular weight polyethylene (UHMWPE) were investigated. As in a previous study, the stress relaxation is interpreted in terms of a model that consists of two thermally activated processes acting parallel. The first process is related to...

The stress-relaxation behaviour of undrawn and drawn linear low density polyethylene (LLDPE) samples has been studied as a function of radiation dose over the range 0–500 kGy. It is shown that stress improves progressively with increasing radiation dose for all the samples, but this effect is greatest for undrawn samples. The crystallinity has been...

Drawn and undrawn samples of gamma-irradiated isotactic polypropylene (iPP) were aged under 0.5 MPa of oxygen at 80 °C. Radiation-induced and post-irradiation effects were observed using infra-red spectroscopy. Changes of the elongation at break and strength at break as functions of aging time and draw ratio were determined from the stress-strain m...