Polymer Science, Series D最新文献

This paper is devoted to estimating the effect of coloring (RAL 7037) polycarbonate and polysulfone with different yellowness indices on a complex of optical, physicomechanical, and rheological properties. It is shown that the introduction of color additives into heat-resistant polymers does not radically change their principal rheological and physicomechanical properties and does not require any modification for the methods and conditions of their processing.

Porphyrin–polymer systems are promising materials for their use in biotechnology, biochemistry, and medicine. The creation of composite materials from porphyrins expands the possibilities of using both high molecular weight compounds and porphyrins. Polylactide–porphyrin film samples obtained by solution watering method are studied in this work. It was found that the density of the film compositions decreases with an increase in an amount of porphyrin in the polymer matrix. A Soret peak of porphyrin immobilized into the polylactide matrix splits (425 and 447 nm) and shifts bathochromically. The addition of 5,10,15,20-tetrakis(4-n-hexyloxyphenyl)porphyrin changes the elastic behavior and strength properties. Shear modulus, elastic modulus, and tensile strength decrease with an increase in an amount of porphyrin in the polylactide matrix. Relative elongation at break increases slightly, and the Poisson’s ratio is almost unchanged compared to those of starting polylactide.

An analysis of methods for separating metal powders of different sizes for gas-thermal coating technologies was carried out. The results of research on the development of a new method for separating different fractions of powders of a given granulometric composition and an installation for their preparation are presented. An algorithm for operating an experimental installation for separating powder materials into fractions is analyzed in detail. The features of reducing the degree of fluctuation increases and the process of fluidization of material particles in the process of their separation are described. Data were obtained to determine and evaluate the relaxation of the gas flow in the proposed installation.

The physicomechanical properties of KGE-3/16 sealant glue and their stability under the influence of thermal cycles and climatic factors simulating long-term storage have been studied. It has been revealed that this sealant glue is resistant to the influence of destabilizing climatic factors, characterized by a high stability of its properties with a unique combination of high strength and elasticity, and can find application in radio electronic equipment.

The potentialities have been studied of using a method for square plate torsion to determine the shear modulus in the plane of a sheet as a sensitive parameter for the aging of polymeric composite materials. The advantage of the method consists in the fact that one can perform the repeated measurements of mechanical parameters without destroying the sample. To substantiate the method, a cycle of drying and humidification of VPS-48 grade fiberglass plates and KMKU-3M, VKU-39, and VKU-45 grade carbon plastics has been performed after 7 years of full-scale holding in a moderately warm climate. The fact that the shear modulus in the sheet plane depends on the moisture content of materials in the course of their humidification and drying has been revealed. It has been proven that the method of square plate torsion can provide a high level of accuracy for measuring the value of this parameter.

An experimental setup and methodology for studying the triboelectric properties of materials at various temperatures are described. The technique is based on recording the electrostatic field that occurs during friction of surfaces of two materials forming a dynamic pair. The use of a tuning fork electrostatic field sensor that has been developed made it possible to carry out measurements in a wide temperature range from –50 to +60°C. Based on the experimental results, the dependences of charge accumulation and decay were obtained for various pairs of shoe materials (felt, leather, natural, and synthetic fabrics).

The production of wood composite materials and, in particular, plywood is one of the most effective ways to utilize waste in order to increase the recycling of by-products. The purpose of the work was to study the possibility of using steelmaking acidic slag as a modifying additive in urea–formaldehyde resins for plywood production and to determine the effect of steelmaking slag on the strength of plywood adhesive joints. The main sources of slag are the oxidation products of cast iron and scrap impurities (silicon, manganese, phosphorus, chromium, etc.), charge materials (lime, limestone, iron and manganese ore, scale, bauxite, fluorspar, etc.), and products of the destruction of refractory linings. As a result of the study, it has been found that the introduction of lignosulfonates, kaolin, and slags into urea–formaldehyde resin increases the reactivity of the finished glue. The ability of metal oxides in slag to bind hydroxyl groups has been proven; in this regard, when heated during pressing, the polymer does not break down into simple monomers, and the free formaldehyde of the urea–formaldehyde resin enters into a polycondensation reaction and is not evaporated from the glue.

The article presents the results of an experimental assessment of the adhesive strength of glass, carbon, and basalt plastics determined by the short beam and pull-out methods. It has been established that the adhesive strength values found by the short beam method depend very little on the chemical nature of a fiber, since the differences between them (using the same matrix and molding technology) do not exceed 5%. The adhesion strength values determined by the pull-out method for samples made with basalt fiber are 12.5% lower than for glass ones and 20% lower than for carbon ones. The article presents the results of statistical analysis, as well as the fracture energy values and the work spent on overcoming friction forces for all types of samples studied.

Modern trends focused on green technologies are driving the increasingly widespread use of biodegradable polymers in agriculture. The development of composite materials based on polylactide (PLA) is aimed at increasing the efficiency of using covering materials for growing plants in agriculture, as well as reducing the amount of polymeric wastes. In this work, mixtures of polylactide/polycaprolactone (PLA/PCL) and polylactide/natural rubber (PLA/NR) have been studied. It is established that, when about 10–15 wt % of PCL and NR are added to the PLA matrix, the structure changes and almost spherical domains are formed. In the course of studying the effect of UV radiation with a wavelength of 254 nm exerted on PLA/PCL and PLA/NR polymeric materials, it has been revealed that the presence of additives in the mixture already in an amount of 10 wt % promotes the inhibition of photolytic processes.

One of the trends in the creation of glazing materials, which are shock-resistant and shatterproof at fracture, is the application of multilayer composites. In this paper, the dependence of the shock resistance and other performance chrematistics of organic-glass-based triplexes on the technology of gluing under natural aging conditions and simultaneous mechanical loads is studied.