Key Engineering Materials Vol. 869

Abstract: This paper presents the results of the study of the effect of polymer materials compression and injection methods of molding on the physical and mechanical properties of the resulting samples. Widely used polymers such as poly-amide, thermoplastic elastomer and polyketone were taken as the objects of study. Granite composites based on polyamide were produced by PolyLab Rheomex RTW 16 twin-screw extruder, then modified with fine powders of schungite, graphite and silicon dioxide. Samples for testing in the form of double-sided blades were obtained by injection molding on a Babyplast 6/10V machine and compression molding on a Gibitre hydraulic press. Elastic-strength tests of the obtained samples were carried out on a tensile testing machine UAI-7000 M.

Abstract: The kinetics of the synthesis of polyaniline in the presence of inorganic fillers was studied. It is shown that the acid-base surface properties of the inorganic filler affect the polymerization time. The introduction of a filler in the reaction mass containing aniline leads to a decrease in the induction period of oxidative polymerization. The decrease in the induction period is due to the fact that aniline is adsorbed on the surface of the filler. This leads to the fact that polyaniline is formed as a thin layer on the surface of the carrier. With a further increase in the content of inorganic filler, the time of the induction period increases. This is due to the fact that the surface of talc has a basic character. The use of mica as an inorganic filler leads to a decrease in the induction period of polymerization in the entire range of the carrier content studied.

Abstract: 4,4'-diallyloxy-2,2-diphenylpropane, based on bisphenol A and allyl bromide wassynthesized. The thermal properties of the obtained products were studied using thermogravimetricanalysis and differential scanning calorimetry. The process of thermal isomerization of allyl groupsin 4,4'-diallyloxy-2,2-diphenylpropane, which is a Claisen rearrangement, was discovered. Allcompounds were characterized by 1H NMR spectroscopy.

Abstract: The work presents the investigations of working out the method of obtaining radio-absorbing composite material based on magnetite nanoparticles and polydimethylsiloxanes. The electron microphotographs of nanoparticles were obtained and the radio-physical characteristics of material in the frequency band of 0.1-8 GHz were measured.

Abstract: Proton-conducting membranes were fabricated from a new short-side chain ionomer Inion (Russian analogue of Aquivion) by solution casting method. A series of temperature treatment experiments was conducted to show that annealing of Inion membranes at the temperature range from 160 °C to 170 °C leads to a significant increase of specific proton conductivity to values even higher than those of commercial membrane Nafion NR212. An explanation of this fact can be given by considering the membranes’ proton transport mechanism and water behavior models in nanopores. Matching the proton conductivity mechanism of the membranes, which is realized in nanostructured channels with the diameter of about several nanometers according to the Grotthuss proton hopping mechanism, and the model of water and ice states in nanopores leads to the comprehensive understanding for the further optimization of the membranes to achieve high transport characteristic. For example, it can be improved by increasing the number of side-chain branches of the polymer.

Abstract: Here we report on reorganization on heating of a perspective organic semiconductor poly(3-(2′-ethyl)hexylthiophene) (P3EHT). P3EHT is an analogue of a well-known poly(3-hexylthiophene) (P3HT), which has comparable optoelectronic properties and the advantage of a lower processing temperature. The processes of structural reorganization during heating of P3EHT have been explored with a combination of synchrotron X-ray scattering and ultrafast chip calorimetry. The signature of reorganization has been identified from an increase of d-spacing of 100 peak of the P3EHT unit cell. It was observed that reorganization operates during heating of P3EHT at conventional rates of a DSC experiment (i.e., at 10 deg/min), whereas it is largely suppressed at a heating rate of 100 deg/s. Despite the absence of reorganization at high heating rates the calorimetric curves exhibit pronounced double melting, which corroborates the model of the negative pressure building up during crystallization of semi-rigid chain polymers.

Abstract: The process technological parameters of forming a film composite for making heat-protective clothing have been developed. The peculiarities of its application in sewing production are taken into account. The effect of the initial polymer compositions formulation on the formed composites physical-mechanical and technological properties was studied. It has been found that the use of the composite film material developed reduces the compounds permeability of protective clothing.

Abstract: In laboratory conditions, oriented polypropylene composite materials containing various concentrations of anisotropic carbon nanoparticles (nanofibers, nanotubes) were obtained. The change in the mechanical properties of oriented composites is determined. Based on structural studies, it was shown that the increase in strength in oriented composites is associated with the formation of a more perfect supramolecular structure of the polymer matrix due to the introduction of low concentrations of nanofillers.

Abstract: In this work we studied the effect of surface treatment of PET films, which are widely used in food packaging, on the adhesion value of ink layers based on polyvinyl chloride. To give high barrier properties to packaging laminates, the films used in their structure are coated with a nanolayer of aluminum oxide (AlOx). However, these films have a disadvantage associated with the low adhesion of adhesive and ink layers to the AlOx nanolayer. To eliminate this disadvantage, aluminium oxide nanolayer is additionally coated with various polymer coatings. In this work we studied the effect of a polyacrylic coating applied on top of an AlOx layer on improving the adhesion of ink layers. For PET films used in food packaging, optical and surface properties are also important. In this regard, additionally we measured surface free energy, coefficient of friction, and optical properties of the studied PET films. We also highlight the relationship of contact angles of wetting and the work of adhesion for the printing ink with the measured adhesion of ink layers.

Abstract: The paper presents an analysis of positions, which a theory of a liquid wetting a solid surface is based on, using the sitting drop equilibrium as an example. Certain inconsistencies are indicated in these positions, which is the subject of the discussion. The paper explains why the interfacial tension of solid-gas has no effect on the equilibrium of a drop. It proposes a mechanism to form a liquid-solid interface layer, the tensor of interfacial tensions of which is represented as a pressure tensor. It is established that the surface tension of the interface layer is variable and changes in magnitude and direction depending on the wetting conditions. It is determined that it is not possible to present a range of phenomena accompanying the wetting of a solid surface with a liquid by examining the equilibrium of a three-phase contact line.