Making technology of copper(II)-coordinated epoxy-amine composites with reduced combustibility has been developed that allowed to form the basis of a new type of polymer with enhanced physicochemical and mechanical properties to improve the process of pouring polymer floors. A proposed simple method allows preparing and incorporating into the epoxy resin matrix the fire retardant-hardeners. These are considered to be the interaction products of the polyethylenepolyamine (PEPA) with inorganic copper(II) salts (specifically, CuSO4, (CuOH)2CO3 and CuSiF6). The combustibility of the DGEBA/PEPA, DGEBA/PEPA-CuSO4, (DGEBA/PEPA)2-(CuOH)2CO3 and DGEBA/PEPA-CuSiF6 composites obtained (DGEBA is bisphenol A diglycidyl ether) were investigated using ceramic tube (CT) method. The flammability of the polymer samples has been evaluated using the UL94 test method according to ASTM 635-14 and ASTM D1929-16. The physical-mechanical properties were determined by considering surface hardness, tensile strength, water absorption, and chemical resistance. The effects of inorganic salts of copper(II) on the fire-hazardous indices and the performance properties of the modified epoxy-amine composites were described. The results of the CT study reveal that the maximum temperature of gases produced through combustion is appreciably decreased, along with weight loss, for modified epoxy-amine composites compared to unmodified composites. The modified polymer composites are attributed to the medium flammability substance class and can be successfully used to pour polymer floors.
Methods for preparation of nanocomposites of modified detonation nanodiamonds (DND) with metallic palladium have been developed and their catalytic activity in the Suzuki-Miyaura cross-coupling reaction in various reaction media has been studied. Methods for the regeneration of palladium-containing nanocomposites from the reaction mixture have been developed. The high catalytic activity of nanocomposites is confirmed by kinetic analysis based on the results of chromatographic analysis of the reaction mixture and is comparable to the literature data about similar catalytic systems. Regenerated nanocomposites showed the retention of catalytic activity for 3 consecutive cross-coupling cycles on model systems.
A model problem of electromagnetic waves diffraction on an equalperiodical multilayered perfectly conducting conical grating is considered. The solution method is based on using the Meler-Fock integral transforms and the method of the coupling problem. This allows both analytical and numerical solutions obtaining. The graphs representing the electric field component dependencies on the time parameter are provided for the case of the single cone with a longitudinal slot.
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