Key Engineering Materials Vol. 899

Abstract: Polymer composite materials based on low molecular weight silicone rubber SKTN-D have been developed, which are supposed to be used as impression materials in dentistry. Vegetable silicon dioxide obtained from rice husk waste was studied as a filler.

Abstract: Novel liquid crystalline oligomers were prepared using different compositions of kink-structured aromatic dicarboxylic acids, aromatic diols, and 4-hydroxybenzoic acid via high-temperature polycondensation. The reaction products were characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, and polarized optical microscopy. As a result, the samples containing kinked units with phenyl or naphthalene moiety had a broad processing window limited by the melting process and the isotropization, whereas one based on diphenic acid was almost entirely in an amorphous state. The surface properties of the oligomers were evaluated by wetting measurements using a static contact angle analysis.

Abstract: The process of oxidation of hydrocarbon with oxygen proceeds with formation of the corresponding hydroperoxide as the primary product [1,2]. A catalyst is the most important factor that influences on the direction of flow of the oxidation reaction. Catalysts based on metals of variable valency, and their derivatives are the most active in reactions of oxidation of hydrocarbon [3].

Abstract: The present paper is aimed to investigate the effect of modifiers, such as poly (phenylene sulfone) and poly (aril ether ketone), on physico-mechanical and thermophysical properties of heat-resistant epoxy-anhydride binder based on EHD epoxy resin. It was found that the addition of poly (phenylene sulfone) and poly (aril ether ketone) can improve mechanical and impact strength characteristics of the binder with no reduction in heat resistance and thermal stability.

Abstract: It was found, studying acrylonitrile copolymerization with ethyl acrylate in dimethyl sulfoxide under the action of anionic initiating system of 1,4-diazabicyclo [2.2.2] octane – ethylene oxide, that the obtained copolymers have a branched structure. An increase in the molar fraction of ethyl acrylate in the reaction medium leads to a decrease in the initial rate of acrylonitrile polymerization. Thermal behavior of copolymer samples was investigated; it was found that ethyl acrylate, being introduced into the polyacrylonitrile structure, both reduces thermal effects related to the reactions taking place during heat treatment of copolymers, and increases the half-width of the heat release peak.

Abstract: The problem of synthesis of polymer suspensions with a narrow particle size distribution is relevant, since the field of their practical application is extremely wide. They are used as calibration standards in electron and optical microscopy and light scattering, for determining the pore size of filters and biological membranes, as model colloids, for studying the kinetics and mechanism of film formation from latex, as well as as polymer carriers of biological ligands in immunochemical studies [1].

Abstract: The article investigates the effect of vulcanizing systems of different activity on the vulcanization and elastic-strength properties of rubber compounds based on ethylene-propylene rubber Keltan . Were taken vulcanizing systems: a mixture of organic peroxide, sulfur and sulfenamide accelerator (1); a mixture of organic peroxide, sulfur and dithiodimorpholine (2); a mixture of organic peroxide, sulfur and thiuram accelerator (3); sulfur and sulfenamide accelerator (4). The vulcanization characteristics (maximum and minimum torques; times of onset, optimum and reaching the maximum speed of vulcanization) were evaluated. Elastic-strength (conditional tensile strength, elongation at break, hardness) properties of rubber compounds and operational (changes in conditional tensile strength, elongation at break after aging in air) were determined. It was found that the vulcanizing system (3) containing sulfur, peroxide in an amount of 7.0 parts by weight and thiuram accelerator imparts the best elastic and strength properties to rubber compounds and leads to their resistance to high temperatures.

Abstract: The paper presents the results of a study of the chemical resistance and mechanical properties of polyphenylene sulfone manufactured by Solvay, Radel brand, obtained by injection molding. Chemical resistance was investigated in short-term tests (24 hours duration), standard (7 days) and long-term (16 weeks). The mechanics of PPSU samples after exposure to chemical reagents is presented. It was revealed in what chemical environments and how much the mechanical properties of polyphenylene sulfone are preserved.

Abstract: The reaction of spontaneous polymerization in the N, N-dialkylaminoethyl methacrylate - alkyl halide system in organic solvent solutions is considered. It is shown that polymerization in the system under study begins only after the formation of quaternary ammonium salt in the reaction medium (at a concentration of about 0.2 mol/L) by the Menshutkin reaction, as a result of quaternization of the unsaturated amine with an alkyl halide. For the explanation of the aggregate of the obtained experimental data, fundamental considerations were formulated, kinetic schemes were developed, and the corresponding mechanism of polymerization processes was proposed.

Abstract: The reaction of spontaneous polymerization in the system of N, N-diethylaminoethyl methacrylate with allyl chloride and bromide, orthophosphoric acid in ethanol and dimethyl sulfoxide solutions is considered. Spontaneous polymerization proceeds, consisting of two stages: the quaternization reaction and the polymerization reaction. It was shown that the accompanying reaction of quaternization, spontaneous polymerization, takes place both in a mixture of reagents and in the presence of a solvent, in other words, and by mixing an unsaturated amine and an alkyl halide.