Polymer Science, Series D最新文献

Matrices modified with polysulfone (PSU) and furfuryl glycidyl ether (FGE) and glass-fiber-reinforced plastics (GFRPs) based on them were investigated. Co-modification of epoxy matrix with FGE and PSU increases the impact resistance of both matrices and GFRPs. In this case, it is possible to regulate the type of phase organization of matrix structure by introducing FGE to ensure the required impact resistance indices of matrices and GFRPs.

The studies of structural parameters of powder materials are discussed in this work. The preparation conditions of grinds for metallographic studies of a surface structure of parts of powder materials are shown. The dashboard is given. New methods to study a structure of powder materials are considered, and they allow one to more fully investigate the structure and properties of parts obtained by the powder metallurgy method.

This work presents the results on the synthesis of new monomers based on 1,1-bis(4-hydroxyphenyl)-2,2-dichloroethene or 1,1-bis(3,5-dibromo-4-hydroxyphenyl)-2,2-dichloroethene and 1,1-di(4-chlorophenyl)-2,2-dichloroethene dihalide. Using these monomers and 4,4′-difluoro diphenyl ketone, halogen-containing unsaturated poly(arylene ether ketones) are prepared by the nucleophilic substitution reaction in N,N-dimethylacetamide. The structure and basic properties of the synthesized poly(arylene ether ketones) are investigated. The composition and structure of the polymer materials are studied by IR spectroscopy, X-ray diffraction analysis, and differential scanning calorimetry. It is shown that poly(arylene ether ketones) are amorphous and well soluble in aliphatic and amide solvents and have good moisture, heat, and fire resistance. Due to high mechanical characteristics these poly(arylene ether ketones) can be recommended as heat-resistant structural polymer materials.

The effect of UV radiation with a wavelength of 253.7 nm on the degradation of polylactide is studied by differential scanning calorimetry, thermogravimetric analysis, and gel permeation chromatography. It is shown that the temperatures and heats of phase transitions of polylactide change in the process of degradation and the thermal stability and molecular weight of the polymer decrease.

The effect of the concentration of modified polyethylene containing various amounts of grafted maleic anhydride on the strength of the adhesive contact of the adhesive–epoxy primer has been studied. Adhesive compositions have been obtained by diluting maleinized polyethylene with low-density polyethylenes of various grades. The properties of the developed compositions have been analyzed for compliance with the requirements for the adhesive layer in three-layer reinforced anticorrosive coatings. It has been found that the best indicators are possessed by compositions based on linear low-density polyethylene of the LL30200 FE grade.

Currently, the use of neural networks allows solving a wide variety of problems: forecasting events, associative information retrieval, product quality control, and many others. In industry, one of the most popular problems to be solved with the help of neural networks is the recognition of visual images. This article discusses the use of neural networks to improve the efficiency and accuracy of manufacturing parts from polymer composite materials (PCMs). An analysis of problems arising at various stages of the technological process of manufacturing parts from PCMs, which can be solved using neural network modeling methods at present, and the prospects for the development of these methods are presented.

This article presents the results of tensile strength and interlayer shear strength assessment of basalt-filled plastics depending on their curing modes. All samples were manufactured using vacuum infusion technology based on epoxy binder (ED-20 resin, isomethyltetrahydrophthalic anhydride as a hardener and methylimidazole as an accelerator). Two types of equipment were used in this work: a standard drying cabinet and an IR heating unit. The curing temperature varied from 120 to 180°C, and the time from 1.5 to 6 h. It was experimentally found that an increase in the curing temperature leads to an increase in the strength properties of basalt-filled plastics by 7.7 and 20.7% under tension and shear, respectively. An increase in the curing time, at the same temperatures, allows increasing the strength of basalt-filled plastic samples and has a positive effect on their long-term resistance to water.

The adhesion strength in thermosetting binder–fiber coated with a layer of the same cured binder joints has been studied using the pull-out method. It has been established that, when using such fibers, the strength of the fiber–matrix interface decreases; i.e., the probability of interlayer failure of composites obtained by multilayer winding increases.

The paper presents data on ageing of VKU-39 aircraft-grade carbon plastic under the moderately warm climate of Gelendzhik and of the Wanning humid tropics. We exposed the material to these conditions for 3 years. The first part of the article considers the general patterns of changes in the mechanical properties of the carbon plastics under thermal, humidity, and natural climatic conditions and presents the results of measuring the strength indicators of the VKU-39 carbon plastic in the initial state and after 1 and 3 years of ageing. When measured at room temperature, the strength limits of the carbon plastic under compression, interlaminar shear, and bending remained at the initial value levels. At the measurement temperature of 120°C, these indicators decreased by 10–24%.

The paper presents the results of studies on the effect of various ultrasonic treatment modes on the polymerization of epoxy adhesive under different temperature conditions. It has been found that the effects arising from the introduction of vibrations during the preparation of the adhesive lead to significant acceleration of polymerization while simultaneously increasing mechanical properties of the adhesive. This effect allows one to intensify the gluing technology by reducing the setting time of the parts to be joined and holding the joint until complete polymerization.