Key Engineering Materials Vol. 869

Abstract: Some properties (enthalpy of formation, glass transition temperature and rheological parameters) of hyperbranched polyglycidol derivatives containing nitrate and azide functional groups were investigated. The dependence of the found properties on the molecular weight, composition and structure of the investigated substances was determined.

Abstract: The authors proposed to use a cell model of the mass transfer process during the composite material formation as applied to the phenomenon of infusion of a viscous binder matrix and a porous structure of the reinforcing filler under the influence of hydraulic vacuum. The model describes the process of filling the capillary-porous reinforcing structure and is the initial stage of creating a numerical model that provides forecasting of the given parameters of the composite material, the technological process, and the operating mode of the equipment.

Abstract: The determination of the stress-strain state of a polymer cylindrical body causes many difficulties. Due to the fact that the properties of polymers are dependent on a number of factors, including temperature. If there is a change in temperature along the radius during the manufacture of the product and production directly depends on dynamic loads, for example rotation, this factor can fundamentally change the distribution of stresses and strains in the thickness of the investigated structure. The body may develop significant residual stresses that reduce the operational quality of the product. Neglect of this factor can have a catastrophic effect on the reliability of the structure as a whole.

Abstract: Rheologic of a polymer pipe from cyclic temperature and internal pressure in one-dimensional and two-dimensional formulations is considered. The resulting equations of the finite element method allow one to calculate both single-layer and multilayer thick-walled pipes taking into account creep. In the calculation, the temperature dependences of the elastic and rheological parameters of polymer pipes were used. The effect of variable thermal conditions on the VAT of a PVC pipe is investigated. It has been established that under unsteady thermal conditions, stresses can occur significantly higher than in a stationary temperature field. This is explained by the fact that polymers have a component of deformation that is lagging in phase from stresses (highly elastic deformation).

Abstract: Compounds based on polyvinylchloride plasticate containing a complex stabilizer based on salts of calcium and zinc stearates were obtained. The thermal properties of the obtained compounds are investigated. It was found that the introduction of a complex stabilizer in PVC compound leads to increased thermal stability of the compound. It is shown that the complex stabilizer affects the destructive processes that occur in the polymer matrix at elevated temperatures. It was found that the introduction of a complex stabilizer based on a mixture of calcium and zinc stearates in polyvinyl chloride plastics results in materials with improved processability.

Abstract: A directed modification of the formulation of industrial PVC plastic brands I40-13A was carried out using zinc borate, antimony oxide and chalk. It was found that the introduction of these additives into the compound can significantly increase the values of the oxygen index and the coke residue of the initial PVC plastic. It was found that a modification of the formulation of industrial PVC plastic leads not only to an increase in fire resistance, but also to a noticeable improvement in the basic physical and mechanical properties of the compound. It is shown that with a slight modification in the formulation of industrial PVC plastic compound it is possible to obtain materials that meet fire safety requirements

Abstract: The influence of carbon black on the deformation-strength properties of high density polyethylene is considered. It was found that the deformation-strength properties of the polymer matrix change over the entire range of the filler content. The amount of carbon black that can be introduced into high-density polyethylene and obtained a composite material with the optimal combination of stiffness, strength and ductility is established. It was shown that the change in the deformation-strength properties of composites is due to the behavior and influence of carbon black particles on the structure of the polymer matrix.

Abstract: The oxidative polymerization of 3-amino-3 ́-nitro-diphenylazomethine was carried out in various ways. In this case, the effect of the concentration of monomer and initiator, their ratio, temperature and reaction time, on the yield and molecular weight of the polymer was studied. The morphology is established, the size of the polymer particles and their distribution are determined. It is shown that the synthesized polymer has increased electrical conductivity and is active in redox processes.

Abstract: The aim of this work was to develop methods for the synthesis of organic aerogels based on epoxy resins and to investigate their properties. Aerogels based on DGEBA-epoxy resin were obtained by CO₂-supercritical drying of gel samples prepared from acetone solutions of epoxy resin with different amount of catalyst and solvents. As a result, aerogels of different density were obtained; the dependence of density on the solvent content in the samples was revealed. The aerogels were characterized by infrared spectroscopy to define the degree of conversion of the epoxy groups, by SEM to confirm nanoscale morphology of aerogels, as well as by the BET method to determine the specific surface area of the samples and its dependence on the catalyst content and curing conditions.

Abstract: This article considers experimental data on the surface charge propagation along the dielectric polymer fibers. Nonwoven polymer materials based on polyhydroxybutyrate obtained by electrospinning technique were used as an example of dielectric fibers in our experiments. Polymer fiber charging was investigated under the electron beam in a vacuum chamber of the scanning electron microscope. The fiber electric response registration was performed in a TV mode and in dynamic conditions using oscilloscopic sectioning visualization. Digitized images were processed using specialized software by Sobel-Feldman operator (Sobel filter), visualizing isopotential lines of the electron beam-induced emission. The results obtained were analyzed in the framework of the Roll’s cable model, which has been extrapolated from the electrical signal transduction along the nerve fibers to the charge propagation along the dielectric polymer fibers.