Polymer Science, Series D最新文献

This study relates to the application of adhesive compositions in the implementation of technological operations in the field of agricultural production. Compositions created on the basis of natural materials of plant or animal origin are recommended for the treatment of flax seeds during the period of planned presowing activities. The proposed technology prevents excessive mucus formation that occurs during the soaking of the seed material, which makes it possible to carry out technological operations that include the use of mechanized stages.

In this article, the chemical and physical properties of products made of powder materials have been considered. It has been established that the corrosion resistance of powder materials, similarly to cast materials, is significantly determined by their chemical composition. It has been shown that, by changing the density and structure in the course of the manufacturing process of powder products, it is possible to change their physical properties over a wide range.

The possibility of regulating adhesive, deformation–strength, and dynamic mechanical properties of adhesive compositions based on diphenylolpropane thioglycidyl ether (thiirane) by changing the content of the hardener and introducing powder fillers has been studied. It is shown that the dependences of adhesive shear strength, tensile and compressive strength, and glass transition temperature on hardener content are extreme. The maximum values of the properties lie in the region of hardener concentrations below the stoichiometric ratio and shift significantly toward lower concentrations as a result of heat treatment of the composites. The reason for this shift is associated with the peculiarities of the chemical interaction of thiiranes with amine hardeners. It is supposed that, in thiirane-based systems with low hardener contents, the polymerization reaction of dithioglycidyl ether makes a significant contribution to the formation of the complex of properties. It is shown that the introduction of powdered fillers makes it possible to increase the strength of thiirane-based composites without reducing the curing rate. This makes it possible to obtain cheaper and more technologically advanced compositions on their basis for the repair and restoration of damaged machine parts and mechanisms without the use of explosion- and fire-hazardous welding and soldering processes.

The main advantages in the application of silicone molds together with master models made by means of FDM 3D printing for the manufacture of road-construction and hoisting-transportation machine parts with the use of investment casting technology are analyzed. The main characteristics are considered, and the advantages and disadvantages of the materials used in the manufacture of silicone casting molds are highlighted. It has been established that, for the use in mechanical engineering and related industries, an individual approach to choosing a material for making molds is most preferable. The main methods for manufacturing silicone casting molds are structured.

The possibility of regulating the curing rate and the complex of adhesive and deformation-strength properties of adhesive materials based on diphenylolpropane thioglycidyl ether (thiirane) has been studied as depending on the chemical nature of amine hardeners, as well as on the composition and ratio of components in curing agents based on their mixtures. The following have been used as initial hardeners: diethylenetriamine of the DETA brand, diethylenetriaminomethylphenol of the UP-583 brand, and aminopolyamide of the PO-300 brand. The ratio of the components of the mixed hardener has been selected to provide the best complex of adhesive and deformation-strength properties. It has been shown that, at the initial stage of curing, the compositions containing the mixed hardener significantly exceed the compositions cured by individual components of the mixture in terms of cohesive strength.

The article considers technologies for producing nontoxic wood–polymer composites using particle boards as an example, produced using an environmentally friendly urea–formaldehyde binder, during the curing of which the AF-2 formaldehyde acceptor was used, which is a chemically active substance with a complex effect in the process of producing wood–polymer composites, simultaneously being an effective accelerator of curing of urea resins and an acceptor of formaldehyde.

The use of carbon-fiber composite materials in medicine is analyzed. The prosthetics, the creation of orthoses, and the application of carbon-fiber-reinforced plastics in medical equipment that operates under the action of X-ray radiation are the main areas to use carbon-fiber-reinforced plastics. Carbon composite materials can be widely used in medicine due to their strength, lightness, and wear resistance. Carbon materials expand significantly the possibilities in treatment, various prosthetics, and rehabilitation of patients.

This article describes some problems in the field of the design and production of composite materials that can be solved using machine-learning technologies. A review of machine-learning techniques is presented together with the existing examples of solving problems in the field of the design and production of composite materials using machine-learning technologies.

Various methods for molding parts of a given geometric shape from polymer composite materials based on epoxy binder and reinforcing fabrics have been considered. The main advantages and disadvantages of each method have been listed. Using the expert method, a comparative assessment of all the considered molding methods has been carried out, which made it possible to determine the most technologically advanced ones for single and small-scale production.

The possibility of modifying an industrial epoxy oligomer with epoxyphosphazene has been considered. The effect of epoxyphosphazene on the fire resistance and chemical resistance to petroleum products of a binder based on ED-20 epoxy-diane resin and a hardener diaminodiphenylmethane has been studied. It has been shown that the introduction of epoxyphosphazene into the epoxy resin contributes to an increase in the impact strength and a decrease in the flame propagation rate. The conducted studies allow one to classify the studied compositions as resistant to the effects of petroleum products.