Polymer Science, Series D最新文献

In the work, changes in the mechanical characteristics of a polymer composition based on polyester resin filled with encapsulated polylactide and nonencapsulated copper(I) oxide particles have been studied, as well as these particles dissolved by the resin components. It has been shown that encapsulated filler particles interact better with the matrix polymer than do nonencapsulated particles. This causes an increase in the ultimate strength and hardness of polymer composite material (PCMs), as well as a decrease in the magnitude of the ultimate deformation. A decrease in the strength characteristics of PCMs was noted in the case of partial dissolution of copper(I) oxide particles by components of the polyester resin. The reason for the change in strength characteristics is a decrease in the density of the polymer binder network due to the loss of styrene, as well as the formation of the complexes of copper salts.

The results of studies on the application of ultrasonic vibrations to parts under gluing are presented. Resulting from cavitation treatment of the glue, its properties are improved, its viscosity decreases and the penetrating ability exhibits an increase. Under the conditions of ultrasonic vibrations, owing to an increase in the surface wettability and the sound-assisted capillary effect, the actual area of gluing increases. Depending on the treatment mode and the surface microgeometry, the application of vibrations leads to an increase in the strength of the adhesive joint from 8 to 43%.

The paper presents the results of a study of the effect of treatment with nanosecond electromagnetic pulses (NEMPs) on some thermodynamic characteristics of polymers used in the production of reinforced fiberglass plastics. It has been found that NEMP treatment of YD-128 epoxy resin, Polysystem VE-3701 LVP vinyl ester resin, and Polysystem YMI-100 polyester resin has a modifying effect. It is noted that the treatment of thermosetting synthetic resins with NEMPs has a modifying effect, which is expressed in a change in viscosity, surface tension and polarity of the resins under study.

The paper considers technologies for the synthesis of amino-formaldehyde resins of KF-MT-NP and AFK-10 grades obtained using the peptization procedure, which could result in the complete elimination of vacuum drying and contribute to the ecologization of the process of synthetic resins production. A modifying additive, which is an inorganic polymer (IP) capable of efficient binding of free formaldehyde in the resin and stabilizing its properties by extending its viability to 6–7 months, is used as a peptizer.

In this work, the ability of calcium, magnesium, and zinc stearates to oxidative destruction of polyethylene was studied. For comparison, the samples of pure polyethylene and polyethylene with the commercial additive D₂W were selected. Infrared spectroscopy data showed that samples with magnesium stearate accumulated double carbon bonds after 96 h of exposure in a climate chamber. In samples with zinc stearate, an asymmetric vibrations of COO groups disappear after 192 h of exposure in a climate chamber. All samples accumulated carbonyl groups resulting from polymer chain scission. After 96 h of aging, the sample with calcium stearate showed better oxidizing properties compared to other stearates. Mechanical test data also confirms the conclusion that the sample with calcium stearate is more susceptible to oxidative degradation among the studied stearates.

A significant number of different types of damage to structural materials, as well as various scenarios of their accumulation, up to destruction, require not only the use of a significant set of experimental methods and the methods of theoretical materials science and molecular physics, but also for developing appropriate mathematical models. These models perform two functions. On the one hand, they make it possible to give a reasonable interpretation of complicated processes, and, on the other hand, they can forecast the evolution of the material under specific operating conditions. Some features characterizing the description of material degradation and destruction based on kinetic approaches are considered.

Today, an important feature of scientific research consists in environmentally safe and biodegradable polymeric materials. Polylactide (PLA) and compositions based on this polymeric compound are being active investigated in world science. One of the main issues that should be considered before using PLA consists in understanding the mechanisms of its biodegradation including mixtures based on this polymer. This work is aimed at studying the mixtures based on PLA with polycaprolactone (PCL) and natural rubber (NR) in the course of biodegradation. After incubation in soil, pure polycaprolactone demonstrates clearly visible structural defects and mycelium on the surface. It has been established that both polycaprolactone and natural rubber undergo biodegradation more rapidly than polylactide. Obtaining PLA/PCL and PLA/NR compositions makes it possible to enhance the effect of biodegradation. As a result of the study, a change in the thermophysical characteristics of the mixtures has been revealed, which indicates the onset of the destruction process.

This article is a continuation of a series of articles on welding parts made of polymer composite materials based on thermoplastics. The fourth article in the series discusses the most common methods of quality control and testing of welded joints of products made of polymer composite materials based on thermoplastic binders. Typical defects in plastic welded joints have been identified. Technologies for destructive and nondestructive testing of welded joints of plastic products are considered.

In this paper, the problem of modifying the physicochemical and rheological characteristics of bitumen binders with polyethylene wax additives is considered. Based on the study of physicochemical and rheological properties, it is shown that the addition of these modifiers results in binders with improved characteristics, such as the softening temperature, rutting resistance, and fatigue cracking. Taking into account the quantitative estimate for the degree of change in the properties of modified bitumen binders, optimal doses of modifiers are determined.

The influence of the concentration of various ethylene–vinyl alcohol (EVAlC) and ethylene–vinyl acetate copolymers on the properties of high-density and low-density polyethylenes is studied to develop compositions for utilization and recycling of polymer multilayer films containing EVAlCs as a barrier layer. It was found that EVAlCs have a lesser negative effect on the properties of mixtures based on high-density polyethylene.