Papers by Keyword: Modification

Abstract: Carbon nitride (C₃N₄) has gained attention from scientists due to its potential applications as a catalyst for organic synthesis, electrodes, photocatalysts, and hydrogen storage materials. Using C₃N₄ as a photocatalyst for the glycerol-to-hydrogen reaction could offer many development advantages. Pure C₃N₄ has several shortcomings as a photocatalyst, so modifications are needed to enhance its properties and characteristics. Converting C₃N₄ into nanosheet form and adding Zirconium doping are solutions to improve its performance. The nanosheet form increases the surface area by creating thin sheet structures, while Zirconium doping is chosen because it can improve the conductivity and mechanical properties of the catalyst. This research focuses on characterizing catalysts with varying doping levels (5%, 10%, 15%, 20%, and 27%). Tests conducted include BET analysis, XRD, and UV-Vis DRS. Results show that the sample with 20% doping performs the best, with a specific surface area of 46.087 m²/g. Crystallinity was assessed with values of 2Ө = 27.8426°, 31.6712°, 45.4188°, and 56.4368°. The band gap energy was determined to be 3.067 eV. These findings are then compared with previous research.

Abstract: This study focuses on the influence of soybean oil (SO) modified by TESPT silane coupling agent as an environmentally friendly processing oil on the properties of the silica-reinforced rubber compounds. A proton nuclear magnetic resonance (¹H-NMR) spectroscopy confirmed that a novel processing oil based on silane-modified SO was successfully prepared in the laboratory. It was found that the unsaturated structures in SO reduced after modification. The properties of the rubber compounds with different types of processing oils were investigated by comparison to the rubber compound without processing oils. The addition of processing oils into the rubber compounds reduced filler-filler interactions within the rubber matrix due to a shielding effect of silica surfaces by processing oils. The silane-modified SO could react with the silanol group on the silica surfaces, leading to a hydrophobicity of silica surfaces. So, the use of silane-modified SO showed lowest filler-filler interactions. In addition to the filler-filler interactions, the presence of processing oils in the rubber compounds reduced the viscosity of the materials as indicated by minimum torque received from a cure curve. The levels of filler-filler interactions in the rubber compounds correlated well with the viscosity. The crosslinking points within the rubber matrix of the oil-added compounds were lower than the one without processing oil. Furthermore, the mechanical properties of the rubber compounds with and without processing oils were considered. The processing oils did not affect the tensile strength, but strongly improved elongation at break.

Abstract: In this article, a regulatory processes study and technological properties of polyamide waste agglomerate modification is carried out. The legal support issues for polymer waste management in Ukraine are considered, ways to improve the most problematic aspects in this area are proposed. The technological properties of polyamide-6 waste agglomerate modification processes were studied in order to improve its technological and strength characteristics. MW-PA CB10 masterbatch modifier impact on the polyamide-6 waste agglomerate technological and strength characteristics complex was studied. It was established that the best is polyamide-6 waste agglomerate with 2 % wt. of masterbatch MW-PA CB10. For this composition the impact strength is 43.5 MPa, breaking stress during bending is 126.4 MPa, tensile strength is 342 N and elongation at break is 117 %. It can be recommended for reuse in traditional fields of primary polyamide-6 to obtain engineering and technical products.

Abstract: An experimental study of the physical and mechanical properties of untreated and acetylated wood was conducted. The effect of acetylation on wood density was investigated. It was established that the density of the samples generally decreases after acetylation. As the level of acetylation increases, the fiber saturation point decreases in both conifers and hardwoods. Acetylation of wood helps to reduce the sorption properties of wood. The amount of swelling was analyzed. For untreated wood (aspen and alder), the volume swelling index is at the level of 7.5 %. Acetylation contributes to the stability of the geometric dimensions of structures, as the volume swelling index for aspen decreased by 4 times, for alder – by 2 times. An increase in the amount of swelling along the fibers is observed in all samples. Regarding the nature of the destruction of the samples during compression, the aspen (both untreated and acetylated) only crumples without visible signs of destruction. In some samples of alder, partial exfoliation is visible. It was found that acetylation has an ambiguous effect on the mechanical properties of wood of both species.

Abstract: The effects of modification, electromagnetic stirring and compound treatment (modification and electromagnetic stirring) on the microstructure and thermal stability of Al-13% Si alloy are experimentally investigated. The results show that the three melt treatments can change the microstructure of the alloy. The modification has obvious refining effect on primary silicon and eutectic silicon grains, electromagnetic stirring has refining effect on primary silicon grains, and eutectic silicon grains appear coarsening phenomenon. The latent heat is obviously decreased by electromagnetic stirring, while the latent heat is increased by modification. Refining eutectic silicon grains will increase the latent heat of phase transformation of the alloy. When 560 °C remains unchanged, the melting temperature of the alloy generally decreases with the increase of holding time, but fluctuates, with a decrease of 7 °C. The latent heat decreases with the increase of constant temperature time, and the decrease amplitude reaches 8.4%.

Abstract: In this paper, a simple and effective method was used to synthesize monodisperse metal Ruthenium nanospheres (Ru-HNSs), and the silicon dioxide (SiO₂) nanospheres synthesized by Stober method were used as hard templates. The surface of SiO₂ was double modified by γ-aminopropyltriethoxysilane (KH550) and salicylaldehyde, so that Ru³⁺ grew uniformly on the surface of modified SiO₂ and reduced to form a stable and durable layer of Ru metal. Then the hard template SiO₂ was corroded by chemical etching to obtain Ru-HNSs hollow spheres. The results show that the diameter of SiO₂ microspheres was about 300nm, the wall thickness of Ru-HNSs was about 3nm, and the diameter was about 100nm.

Abstract: This article presents the results of a study on the effect of carbon nanosized additives on the structure and properties of cement-based materials. The use of a carbon black dispersion as an alternative to an expensive dispersion of carbon nanotubes is proposed. Based on the experimental data, it is proven that the introduction of carbon black particles into the composition of the cement matrix in an amount of 0.2% by the weight of cement leads to an increase in strength of the cement stone, in both compression and bending, by 21% and 8%, respectively. This increase is compatible with the results obtained when cement matrix was modified with a dispersion of carbon nanotubes.IR spectral and thermal analysis of the modified cement matrix, as well as the study of its microstructure, confirm the formation of a dense net of cement hydration products, including low-basic calcium silicate hydrates and secondary nanosized globular thaumasite formations that contribute to the compaction of the material structure and the following increase in strength.

Abstract: Research on investigation of hybrid eco-friendly polymers modificated by humic substances are given in this article. The purpose of the research is to investigate a hybrid modification of eco-friendly polymers of polylactic acid by humic substances, it was found that the mechanism of hybrid modification in the matrix synthesis of the polylactic acid-humic substances system indicates an intermolecular bond between polylactic acid and humic substances, at the same time, due to increased crystallization and the emergence of intermolecular and ester bonds in the formation of more rigid mesh structure in the system polylactic acid-humic substances is increasing the mechanical properties of such materials. It was found that the increase in the impact strength and the breaking stress during bending in the polylactic acid-humic substances system in the hybrid modification occurs, while the optimal content of humic substances in the polylactic acid-humic substances systems is 0.5 % by mass.

Abstract: The work is devoted to solving the current problem of increasing the level of environmental safety of treatment industrial wastewater of leather production from chromium ions (III) through the use of natural and modified bentonite. The investigation about the efficiency of purification of model solutions, which containe 1 g/dm³ of chromium ions and 0.75 g/dm³ of phosphate ions was carried out by the method of ideal displacement. In our research, we proposed a method of sequential adsorption, according to which phosphate ions are absorbed in the first stage and chromium ions are sequentially adsorbed in the second stage. Structural features of natural carbonate-rich and modified with chromium and phosphate ions bentonite clay have been studied. researched and analyzed.

Abstract: The sorption method of purification of flushing water from non-ferrous metal ions in galvanizing-bath rooms of mechanical facilities was investigated, which is one of the most realistic ways to solve the problem of environmental protection from such pollution. The effect of preliminary thermal and chemical modification of the crystal structure in order to improve the sorption capacity of clinoptilolite was established. The kinetics of the copper ion exchange process on clinoptilolite in static conditions was determined.