Polymer Science, Series D最新文献

Data concerning the studies on the potentialities of using low-melting glass in order to expand the softening range of a heat-resistant coating based on a high-melting glass-forming system. The effect of low-melting glass-forming agents on the stability of the silicon–oxygen frame, the deformation onset temperature and the coefficient of thermal expansion is assessed. It has been shown that the introduction of the Al₂O₃–B₂O₃–SiO₂ system into the glass composition provides an increase in the mobility of the structural elements of the glassy component. Therefore, in order to maintain the heat-resistant properties of the coating and to improve the viscous flow processes, it is necessary to pay attention to the structural state of aluminum and boron ions in the composition.

The electrophysical properties of ionic liquids with different chemical structures of their anions and fillers, as well as a polymer material containing ionic liquids, were studied.

Mulch films are intensively used to increase productivity in agriculture. A large amount of plastic waste from mulch films is accumulated in the topsoil of agricultural fields around the world. A solution to this problem is the replacement of disposable plastics by biodegradable ones. The paper presents the results of tests of polylactide-based biodegradable materials for agriculture. It is shown that despite hydrophobicity polylactide is easily hydrolyzed, which subsequently leads to destruction of the films based on it. An analysis of the biodegradability of the materials obtained shows that after incubation in a soil for 90 days the weight loss of pure PLA of various grades is lower than that of PLA/PBAT and PLA/NR mixtures and the thermophysical characteristics of PLA change: its melting temperature decreases by 2–5°C and the degree of crystallinity decreases by 2–6%.

The fractures of compact samples after static crack resistance testing, in which the crack on the addfracture site rotates at a right angle with respect to the plane of the initial (fatigue) crack. Possible reasons for the formation of this shape of fractures are analyzed. It is shown that one of the possible reasons for crack rotation consists in the presence of residual stresses in the sample body. To assess the magnitude of residual stresses, a template has been cut out from a part of a compact sample tested for static crack resistance subsequently examined by means of a double-sided layer removal technique. The presence of residual stresses in the direction parallel to the initial fatigue crack has been demonstrated, which confirms the conclusions made regarding a possible effect of residual stresses exerted on crack rotation in the course of addfracture.

It is shown that the injection molding of thin-walled products with a thickness of less than ~1 mm can be difficult in the case of particulate-filled polymer composite materials (PFPCMs) with MFS-1, MFS-2, and HFS types of structure. Products with a wall thickness of more than ~3 mm and L/h ≤ 100 can be obtained by injection molding using almost all PFPCM structure types (DS, LFS, MFS-1, MFS-2, and HFS) at the processing temperatures. However, when the L/h ratio increases, the products may be difficult to process using injection molding. For the first time, dependences are established for pressure losses at injection molding on generalized parameters and PFPCM dispersion structure type and product size. Such an approach makes it possible to predict and choose the required process parameters and injection molding machines for processing the majority of PFPCMs with different types of dispersed structures based on polymer matrixes and solid dispersion fillers.

The review is devoted to analyzing published information concerning biodegradable biliary stents, materials and manufacturing technology, and methods of testing.

The properties of a polyurethane composition modified with rubber are considered. In terms of its composition and purpose, the adhesive composition is close to VK-11 polyurethane glue. However, the VK-11 grade glue contains polyvinyl chloride resin that is not produced in Russia. It has been shown that the polyurethane composition is capable of curing at a room temperature or in an accelerated curing mode at a temperature of +80°C for 2 h. The testing results for an experimental polyurethane adhesive composition modified with rubber are presented for gluing a number of metallic and nonmetallic materials in the temperature range from –60 to +80°C.

Technological and operational characteristics of the VK-105 film adhesive developed by the All-Russian Research Institute of Aviation Materials, National Research Center “Kurchatov Institute”, have been considered. The results of rheological tests of the binder in dynamic and isothermal modes have been presented. The influence of the conditions for forming the adhesive film on the strength characteristics of the adhesive joint has been studied, and the performance characteristics of VK-105 adhesive have been compared with the existing analogues.

A classification of materials used as fire retardants is given, and their properties and fields of application are considered. Mechanisms of protection against fire are considered for fire retardants of different chemical nature along with their advantages and drawbacks.

This review examines the basic principles of 3D printing from polymer materials with an emphasis on modeling technology using the fused deposition modeling (FMD) method. Polymers used as raw materials for FDM technology are described in detail. Technological features of a process and the main equipment are considered. Advantages and disadvantages of this technology are discussed.