Materials Science Forum Vol. 1126

Abstract: Growing interest in utilizing and processing natural fibres (NF) to create biodegradable and sustainable composites as environmental concerns upsurge globally. Date palm trees (DPT) account for more than 4.5 million tons of waste annually worldwide, making it one of the most abundant agricultural biomass waste in the MENA region. This study evaluated the biological resistance of thermoplastic composites developed from polylactic acid (PLA) and recycled polyvinyl chloride (RPVC) reinforced with date palm fibre (DPF) at different contents (10, 20, 30, 40 wt.%) and fibre size (250 – 500 µm and ≥1,000 µm). Composites where exposed to the brown-rot fungus; Irpex lacteus, and white-rot fungus; Tyromyces palustris, to evaluate its resistance to biodegradation. Results showed that composites developed using PLA had higher weight loss (%) when compared to the same samples but reinforced with RPVC. Composites with higher DPF content showed high rates of decay when used with different polymer matrix. Also, DPF length had a significant effect on the disintegration of the composites. DPF/PLA reinforced with 40 wt.% DPF showed the highest weight loss (WL%) reaching 5.61% and 5.46% when exposed to Tyromyces palustris and Irpex lacteus respectively. On the other hand, the biodegradation had a direct impact on the disintegration of the composites developed where the WL%, of PLA composites developed with 40 wt.% DPF showed 61.40%.

Abstract: Surface modifications of bio-filler and polymer matrix is critical in natural fiber reinforced composites to improve compatibility with the hosting polymer. The literature contains only a few studies on grafting bio-fillers to improve their reactivity with polymer matrix. This study focuses on introducing crosslinking between Date Palm Particles (DPP) and Polypropylene (PP) using new methods. The experimental setup starts with chemical modifications of PP that result in the formation of PP-g-mTMI. Following that, the two components are blended together, forming a urethane link between the filler and the polymer. Following the fabrication of bio-composite sheets based on the Taguchi design, various specimens were prepared and tested thoroughly to assess their chemical properties, thermal stability, and mechanical properties. The results of the experiments revealed an improvement in the interfacial adhesion of the filler/polymer, which was confirmed by experimental mechanical characterization and Scanning Electron Microscope (SEM) analysis. The new composite demonstrated improved strength, ductility, and overall durability, demonstrating its potential as a bio-based polymeric material.

Abstract: The work introduces an improved mode of production of steel sheets of the C355Zh2 type recommended for industrial use in factory conditions in Ukraine; this contributed to reducing the dispersion of the values of the strength and plasticity indicators of the finished product and increasing the yield of suitable products obtained using the proposed mode of controlled rolling.

Abstract: Achieving dependable connections in open construction settings presents challenges or renders the use of stationary machines and equipment complicated, if not impossible. Therefore, there is a particular focus on the requirements for welding processes. Of particular interest is ensuring the strength and reliability of welded joints, especially through processes developed subsequent to the solidification of the weld at the weld zone. The extent of the thermal influence zone is contingent upon the welding conditions and the properties of the metal being welded. Hence, research into the impact of welding conditions on the formation of the structure of the welded zone and the thermal influence zone remains pertinent.

Abstract: This scientific work justifies imaging and visualization methods for analyzing heterogeneous PA-1 structures at micro- and nanoscales. It explores a key aspect of studying heterogeneous materials, namely the relationship between their microstructure and macroscopic behavior. Using Smart-EYE software, the microstructure and heterogeneous structure of PA-1 aluminum powders are justified through a range of factors. Among them, the extended functionality of the program allows for detailed analysis of particle sizes, shapes, and distribution, ensuring high accuracy and reliability of the analysis results. The capability for quick and efficient analysis of large volumes of data is also highlighted. Additionally, the software enables visualization of analysis results, simplifying their interpretation. Furthermore, the obtained results based on the histogram of particle size distribution, such as normal distribution, skewness, and modality, help avoid minor data defects and ensure proper interpretation.

Abstract: The intensity of heating of the insulation material of loaded electric wires was investigated. Calculations were made for insulation materials made of polyvinyl chloride plastic and rubber, and copper and aluminum wires. The dependences of the heating temperature of the wires on the time of their operation at load currents smaller, close to and larger than the maximum allowable ones are plotted. The time during which you spend heated to critical temperatures, is individual for each brand-size. For wires with a copper core, heating occurs more slowly compared to wires with an aluminum core. Wires with polyvinyl chloride core insulation heat up more slowly than wires with rubber core insulation. In all cases, addiction temperature of the wires from the time of operation at different load currents has a logarithmic form.

Abstract: Comparative studies of the corrosion and electrochemical properties of amalgam filling materials based on copper, silver and non-gamma-2 "Oralloy" amalgam (Switzerland) were carried out in aqueous solutions of sodium chloride, sodium bicarbonate and citric acid at room temperatures and under conditions of mechanical depassivation of the surface. Although copper amalgam is corrosion-resistant in control environments due to the formation of protective passivating layers on the surface, the test results show that the advantage of silver amalgam in all tested solutions is obvious. It has been confirmed that the “Oralloy” filling material has advantages over copper and silver amalgams in the corrosion-electrochemical aspect. It is corrosion resistant in physiological neutral and slightly alkaline solutions, like silver amalgam, but surpasses it in electrochemical inertness. It has been shown that when predicting the intensity of galvanic processes that occur in the presence of two or more dissimilar metallic inclusions in the oral cavity, the potential difference between them is a necessary but insufficient criterion. When deciding the compatibility of new filling materials and previously used ones, it is necessary to take into account the pH of the environment, the potential difference between them, their nature and surface condition, as well as their position on the surface of the teeth. If there is a possibility of abrasion of the amalgam surface by antagonist teeth, then the likelihood of galvanosis increases significantly.