J. Compos. Sci., Volume 8, Issue 5 (May 2024) – 12 articles

Fly ash has been utilized as a reinforcing material in the production of aluminum matrix composites, and in this investigation, Al-Si (LM6) fly ash composites were fabricated using the compocasting method. Various compositions of fly ash were incorporated into the samples (4, 5 and 6 wt%), and the preparation temperature ranged from 560 to 800°C. This study investigated the thermal (CTE and DTA) and chemical properties (XRD) of fly ash reinforcement and the aluminum melt in the composites. The results revealed that composites with 5 wt% of fly ash exhibited the lowest CTE value compared to those with 4 and 6 wt%. This observation was corroborated by XRD analysis, indicating a reaction between the fly ash particles and the aluminum melt. However, the DTA analysis did not find a significant impact of the addition of fly ash on the melting temperature of the prepared composites. In contrast, this study identified and investigated the existence of reaction effects between the fly ash particles and the aluminum melt. Full article

Polylactic acid (PLA) is considered a promising biodegradable polymer alternative. Due to its high brittleness, composite materials made by melt blending thermoplastic polyurethane (TPU) with PLA can enhance the toughness of PLA. To understand the forced aging caused by stress relaxation in polymer materials, this study explains the stress relaxation experiments of PLA/TPU blends with different mass ratios under applied strain through mechanical model simulations. The Kelvin representation of the standard linear solid model (SLSM) is used to analyze the stress relaxation data of TPU/PLA blends, successfully explaining that the Young’s moduli (E₁ and E₂) of springs decrease with increasing temperature and TPU content. The viscosity coefficient of the PLA/TPU blends decreases with increasing temperature, and its reciprocal follows the Arrhenius law. For TPU/PLA blends with increased concentration of TPU, the activation energy for stress relaxation shows a linear decrease, confirmed by the glass transition point measured by DMA, indicating that it does not involve chemical reactions. Full article

Lost-wax glass casting, an esteemed yet technically demanding art form, traditionally relies on specialized, costly kiln equipment, presenting significant barriers to artists regarding equipment affordability, energy efficiency, and the technical mastery required for temperature control. Therefore, this study introduces an innovative approach by integrating a microwave kiln with standard household microwave ovens, thus facilitating the lost-wax glass casting process. This methodological adaptation allows artists to employ readily available home appliances for glass creation, significantly reducing the process’s cost and complexity. Our experimental investigations reveal that, by using a 500W household microwave oven for heating, the silicon carbide (SiC) in microwave kilns can efficiently absorb microwave energy, allowing the kilns to reach temperatures exceeding 700 °C, a critical threshold for casting glass softening. We further demonstrate that by adjusting the number of heating cycles, producing high-quality, three-dimensional(3D) glass artworks is feasible, even for large-scale projects. In addition, the microwave kiln can be used as an effective cooling tool to uniformly cool the formed casting glass. This study presents a possible alternative to conventional kiln technology and marks a paradigm shift in glassmaking, offering a more accessible and sustainable avenue for artists and practitioners. Full article

The rapid growth of Natural Fiber Laminate (NFL) innovation is a direct response to environmental challenges, positioning these materials as superior alternatives to synthetic fiber composites. This paper delved into the outcomes of an extensive experimental study investigating the influence of sisal fiber (SLF), banana fiber (BF), and glass fiber (GF) on the mechanical and microstructural characteristics of concrete. The water absorption curves were established for sisal fiber concrete (SLFC), banana fiber concrete (BFC), and glass fiber concrete (GFC). Furthermore, Scanning Electron Microscope (SEM) observations were conducted to perform microanalysis and failure analysis of the tested specimens. The results revealed significant improvements in the concrete containing fibers compared to its counterpart in fiber-free concrete. For mixtures with a water-to-binder (W/B) ratio of 0.3, the most optimal mix (GF-30-135) showed improvements in compressive strength, flexural strength, and splitting tensile strengths by 4.13%, 8.93%, and 10.10%, respectively. On the other hand, for W/B of 0.4, mix GF-30-135 showed improvements of 5.05%, 8.55%, and 11.60%, respectively. Furthermore, as the fiber content increased, microscopic analyses revealed a weakening of the bond between the fibers and the rest of the matrix, contributing to the deterioration of the mechanical properties. Full article

The relevance of involving substandard raw materials for the production of composite phosphorus-containing fertilizer production is significant due to the problem of providing food products for the growing population of the Earth. The main raw materials for phosphorus and composite phosphorus-containing fertilizer production are natural phosphate ores—phosphorites. However, in the process of mining and crushing, ~55–60% phosphorite ore fines are formed—a fraction of less than 10 mm, which is unsuitable for traditional processing into composite phosphorus-containing fertilizers. This article presents the results of physicochemical studies of the substandard fine fraction of phosphorite ore and the results of the studies of the possibility of their direct processing into phosphorus and composition of phosphorus-containing fertilizers using methods of mechanical and mechanochemical activation in the “Activator 4” planetary mill. The findings of the studies performed confirm the rather high efficiency of phosphorite ore fines’ mechanical activation and phosphorite-containing mixtures’ mechanochemical activation, which make it possible to significantly increase the content of assimilable phosphorus pentoxide P₂O₅ in composite phosphorus-containing fertilizers. The proposed innovative technology has fundamental differences from existing technologies, since the mechanochemical activation of a mixture of phosphorite ore fines and functional components will allow for direct acid-free and waste-free processing into phosphorus and composite phosphorus-containing mineral fertilizers. Full article

This paper presents a novel ultrasonic-assisted electrodeposition process of Mn-doped NiCo₂O₄ onto a commercial nickel foam in a neutral electroplating bath (pH = 7.0) under an ultrasonic power of 1.2 V and 100 W. Different sample properties were studied based on their crystallinity through X-ray diffraction (XRD), morphology was studied through scanning electron microscopy (SEM), and photodegradation was studied through ultraviolet–visible (UV–Vis) spectrophotometry. Based on the XRD results, the dominant crystallite phase obtained was shown to be a pure single NiCo₂O₄ phase. The optical properties of the photocatalytic film showed a range of energy band gaps between 1.72 and 1.73 eV from the absorption spectrum. The surface hydroxyl groups on the catalytic surface of the Mn-doped NiCo₂O₄ thin films showed significant improvements in removing methyl red via photodegradation, achieving 88% degradation in 60 min, which was approximately 1.6 times higher than that of pure NiCo₂O₄ thin films. The maximum hydrogen rate of the composite films under 100 mW/cm² illumination was 38 μmol/cm² with a +3.5 V external potential. The electrochemical performance test also showed a high capacity retention rate (96% after 5000 charge–discharge cycles), high capacity (260 Fg⁻¹), and low intrinsic resistance (0.8 Ω). This work concludes that the Mn-doped NiCo₂O₄ hybrid with oxygen-poor conditions (oxygen vacancies) is a promising composite electrode candidate for methyl red removal, hydrogen evolution, and high-performance hybrid supercapacitor applications. Full article

The formation of a rigid, tough interface based on a nacre-like structure in carbon fiber (CF) composites is a promising way to eliminate low delamination resistance. An effective method of coating CFs is electrophoretic deposition (EPD), which, in the case of dissimilar components like graphene oxide (GO) and polymeric glue, usually requires chemical bonding/strong interactions. In this work, we focus on chitin nanocrystals (ChNCs), leading to an excellent mechanical performance of artificial nacre, where favorable interactions and bonding with GO are controlled by degrees of deacetylation (5, 15, and 30%). We prepared coatings based on GO/ChNC adducts with 95/5, 90/10, 50/50, and 25/75 ratios using optimized EPD conditions (pH, concentration, voltage, and time). The prepared materials were characterized using FTIR, TEM, XPS, SEM, DLS, and XRD. SEM evaluation indicates the formation of a homogeneous interlayer, which has a fair potential for chemical bonding with the epoxy matrix. Short-beam testing of epoxy matrix composites indicates that the coating does not decrease stiffness and has a relatively low dependence on composition. Therefore, all coatings are promising for a detailed study of delamination resistance using laminate samples. Moreover, facile EPD from the water solution/suspension has a fair potential for industrial applications. Full article

An approach is demonstrated for the generation of swellable core–shell particles in the sub-millimeter range using a one-step microfluidic method. Particles are made of an agarose gel core and a shell consisting of hydrogel based on crosslinked poly-(N-isopropylacrylamide) (PNIPAM). Solidification of the core was achieved by cooling below the sol–gel temperature, while the shell was cured by photoinitiated co-polymerization. The shell of the particles is reversibly thermoresponsive; it contracts upon heating, releasing water, and becomes hydrophobic. The transition temperature as well as the stability of the particles are mainly affected by the shell monomer composition, while they are less affected by the type of the core material. Such composite particles remain swellable after drying. Full article

The utilisation of Portland cement has aroused tremendous concerns owing to its production exerting a lot of pressure on the environment. Alternative eco-binders have been developed to replace it, among which alkali-activated materials (AAMs) have drawn great attention, especially due to the possibility of encompassing industrial and agricultural waste, which significantly improves the sustainability and cost-efficiency of the material. Biomass wood ash (BWA) is a by-product generated from power plants and, along with the advocation for biomass fuel as a renewable energy resource, there have been increasing applications of BWA in building and construction materials. This review examines the use of BWA as a precursor source in AAMs. Due to its low chemical and hydraulic reactivity, more active binary precursors are usually introduced to guarantee mechanical properties. Whereas the increment of BWA content can have a negative influence on material strength development, it is still a promising and feasible material, and new approaches should be developed to improve the effectiveness of its utilisation. Currently, study of BWA-based AAMs is still in the beginning stages and more research is needed to investigate the effects of BWA characteristics on the property evolution of AAMs, focusing on the durability and analysis of eco-efficiency. Overall, this review provides a comprehensive overview of the characterisation of BWA and its potential applications in AAMs, and meanwhile, based on the analysis of present research trends, proposes some prospective directions for future research. Full article

The corrosion of steel materials has become a global issue, causing significant socio-economic losses and safety concerns. Hot-dip galvanizing is currently one of the most widely used steel anti-corrosion processes. With the rapid advancement of science and technology and emerging industries, the performance of pure galvanized products struggles to meet the demands of practical applications in various environments. Consequently, researchers have begun introducing various metals into the zinc solution to form high-performance alloy coatings. This article primarily explains the process flow of hot-dip galvanizing and the impact of metal elements such as Al, Mg, Sn, and Bi on the coating, as well as outlining the major issues currently faced by the hot-dip galvanizing process. The objective is to offer a more comprehensive introduction to those new to the field of hot-dip galvanizing and to provide theoretical insights for addressing production issues. Full article

This paper presents a numerical study on the dynamic response and impact mitigation capabilities of layered ceramic–polymer–metal (CPM) composites under plate impact loading, focusing on the layer sequence effect. The layered structure, comprising a ceramic for hardness and thermal resistance, a polymer for energy absorption, and a metal for strength and ductility, is analyzed to evaluate its effectiveness in mitigating the impact loading. The simulations employed the VUMAT subroutine of DSGZ material models within Abaqus/Explicit to accurately represent the mechanical behavior of the polymeric materials in the composites. The VUMAT implementation incorporates the explicit time integration scheme and the implicit radial return mapping algorithm. A safe-version Newton–Raphson method is applied for numerically solving the differential equations of the $J_2$ plastic flow theory. Analysis of the simulation results reveals that specific layer configurations significantly influence wave propagation, leading to variations in energy absorption and stress distribution within the material. Notably, certain layer sequences, such as P-C-M and C-P-M, exhibit enhanced impact mitigation with a superior ability to dissipate and redirect the impact energy. This phenomenon is tied to the interactions between the material properties of the ceramic, polymer, and metal, emphasizing the necessity of precise material characterization and enhanced understanding of the layer sequencing effect for optimizing composite designs for impact mitigation. The integration of empirical data with simulation methods provides a comprehensive framework for optimizing composite designs in high-impact scenarios. In the general fields of materials science and impact engineering, the current research offers some guidance for practical applications, underscoring the need for detailed simulations to capture the high-strain-rate dynamic responses of multilayered composites. Full article