J. Compos. Sci., Volume 6, Issue 10 (October 2022) – 43 articles

Wood–plastic composites (WPC) are enjoying a steady increase in popularity. In addition to the extrusion of decking boards, the material is also used increasingly in injection molding. Depending on the formulation, geometry and process parameters, WPC tends to exhibit irregular filling behavior, similar to the processing of thermosets. In this work, the influence of matrix material and wood fiber content on the flow, mold filling and segregation behavior of WPC is analyzed. For this purpose, investigations were carried out on a flow spiral and a sheet cavity. WPC based on thermoplastic polyurethane (TPU) achieves significantly higher flow path lengths at a wood mass content of 30% than polypropylene (PP)-based WPC. The opposite behavior occurs at higher wood contents due to the different shear thinning behavior. Slightly decreased wood contents could be observed at the beginning of the flow path and greatly increased wood contents at the end of the flow path, compared to the starting material. When using the plate cavity, flow anomalies in the form of free jets occur as a function of the wood content, with TPU exhibiting the more critical behavior. The flow front is frayed, but in contrast to the flow spiral, no significant wood accumulation could be detected due to the shorter flow path lengths. Full article

Volcanic concrete is an eco-friendly concrete type in that it contains coarse and fine aggregates that all extracted from the igneous volcanic rock. However, utilizing of volcanic ash (VA) as partial/full replacement of concrete cement significantly affects the concrete workability, especially at high cement replacement ratios. This has also some adverse effects on concrete strength. Utilizing magnetized water (MW) in concrete as a partial/full replacement of ordinary tap water (TW) has a notable effect on enhancing the fresh and hardened concrete properties. This research aims to study the effect of using MW prepared in a magnetic field of 1.4 Tesla on the workability and hardened properties (compressive, tensile, and flexural strengths) of volcanic concrete. In this study, VA partially replaced volcanic concrete cement with ratios of 5%, 10%, 15%, and 20%. Ten volcanic concrete mixes were prepared in two groups. The first one was prepared with VA (0–20%) and mixed with TW. The other group was prepared with the same VA contents like group one, but mixed with MW. Microstructure imaging for volcanic concrete was also conducted in this study. Results of water tests showed 17% and 15% increase in total dissolved solids (TDS) and pH, respectively, of MW compared with those of TW. In addition, the water magnetization decreased the water surface tension by 7% compared with that of TW. Results of hardened concrete tests showed that the best ratio of VA in volcanic concrete was 5% with and without using magnetized water. The volcanic concrete slump decreased when using TW; however, using MW enhanced the volcanic concrete slump by up to 8%. The compressive strength was improved by 35%, 23%, and 20% at 7 days, 28 days, and 120 days, respectively, with no VA and with the presence of MW. The compressive strength was improved by 11%, 12%, and 11% after 7 days, 28 days, and 120 days, respectively, with using 5% VA and with the presence of MW. Both splitting tensile strength and flexural strength of volcanic concrete with and without VA or MW behaved similar to that of the corresponding compressive strength. Full article

The wedge-loaded asymmetric double cantilever beam (WADCB) test is an experimental method to determine the mixed-mode I/II fracture toughness of composite materials by inserting a wedge into the specimen along a potential delamination path. Whilst the current closed-form solution for the ADCB test assumes identical forces acting in both specimen arms, this manuscript proposes a refined closed-form solution allowing for different forces acting on both specimen arms, which is thought to be more general and more rigorous. WADCB tests were carried out on composites made from Torayca T700SC/2592 unidirectional prepreg. Both the current and the refined closed-form solution were used to analyze the data, and some differences were found in the predictions, indicating that the forces in the two specimen arms are indeed not identical. Full article

The 3D shear deformation and failure behaviour of a glass fibre reinforced polypropylene in a shear strain rate range of $\dot{\gamma }=2.2\times {10}^{-4}\mathrm{to}3.4\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$\mathrm{s}$}\right.$ is investigated. An Iosipescu testing setup on a servo-hydraulic high speed testing unit is used to experimentally characterise the in-plane and out-of-plane behaviour utilising three specimen configurations (12-, 13- and 31-direction). The experimental procedure as well as the testing results are presented and discussed. The measured shear stress–shear strain relations indicate a highly nonlinear behaviour and a distinct rate dependency. Two methods are investigated to derive according material characteristics: a classical engineering approach based on moduli and strengths and a data driven approach based on the curve progression. In all cases a Johnson–Cook based formulation is used to describe rate dependency. The analysis methodologies as well as the derived model parameters are described and discussed in detail. It is shown that a phenomenologically enhanced regression can be used to obtain material characteristics for a generalising constitutive model based on the data driven approach. Full article

In this work, we report the synthesis of Mn-doped Cu₂O nanoparticles using aloe vera leaves extract. X-ray diffraction data revealed that the Mn-doped Cu₂O crystals have a cubic crystal structure. The surface morphology of the as-synthesized catalyst indicated truncated octahedral and spherical-like shapes. The photocatalytic activity of the catalyst is efficient at pH 9, initial concentration of amoxicillin 15 mg/L, and photocatalyst dosage 1 g/L under sunlight irradiation. 92% of amoxicillin was degraded in the presence of Mn-doped Cu₂O. The enhancement in photocatalytic performance is due to the incorporation of Mn, which delays the rapid recombination rate by trapping the photogenerated electron. Therefore, Mn-doped Cu₂O could remove pharmaceuticals from pharmaceutical factory and hospital wastes. Full article

Polyvinyl alcohol (PVA) has been used in packaging applications due to its biocompatibility and biodegradability. However, this non-toxic synthetic material belonging to a highly hydrophilic polymer has poor resistance to wet environments, no antibacterial activity, and low tensile and thermal properties. This study aims to prepare and characterize a PVA-based biocomposite film mixed with antimicrobial white ginger nanocellulose (GCNF) and zinc oxide (ZnO) nanoparticles. The film was processed using GCNF (0.1 g) or/and ZnO nanoparticles (0.5 g). The results confirm that the GCNF/ZnO/PVA-based film presents the strongest antimicrobial activity and the highest thermal resistance. This film also had the best value in tensile strength (19.7 MPa) and modulus (253.1 MPa); 63.9% and 117.9%, respectively higher than purce PVA. Its elongation at break was 56.6%, not statistically significantly different from the pure PVA film. Thus, this PVA-based hybrid biocomposite film reinforced by GCNF and ZnO has excellent potential for fresh food packaging in industrial applications. Full article

The scope of this work was to develop novel polymer composites via melt extrusion and 3D printing, incorporating High-Density Polyethylene filled with zinc oxide particles in various wt. percentages. For each case scenario, a filament of approximately 1.75 mm in diameter was fabricated. Samples for tensile and flexural testing were fabricated with 3D printing. They were then evaluated for their mechanical response according to ASTM standards. According to the documented testing data, the filler increases the mechanical strength of pure HDPE at specific filler concentrations. The highest values reported were a 54.6% increase in the flexural strength with HDPE/ZnO 0.5 wt.% and a 53.8% increase in the tensile strength with 10 wt.% ZnO loading in the composite. Scanning Electron Microscopy (SEM), Raman, and thermal characterization techniques were used. The experimental findings were evaluated in other research areas where they were applicable. Full article

Ceramics based on rhenanite CaNaPO₄ with density of 0.94 g/cm³ and compressive strength of 10.3 MPa was obtained via firing at 900 °C of composite cement-salt stone prepared from a hardening powder mixture of calcium citrate tetrahydrate Ca₃(C₆H₅O₇)₂∙4H₂O and sodium dihydrogen phosphate NaH₂PO₄. The phase composition of the obtained samples of cement–salt stone was represented by monetite CaHPO₄, unreacted sodium dihydrogen phosphate and calcium citrate tetrahydrate. According to the XRD data, the phase composition of the ceramic samples after annealing in the temperature range of 500–700 °C was mainly represented by the β-CaNaPO₄ phase. It was found that after an annealing at temperature of 900 °C, the phase composition of ceramics was presented with the only phase of β-CaNaPO₄. It was demonstrated that an increase in the annealing temperature led to an increase in the grain size from 1 μm after annealing at 500 °C to 5 μm after annealing at 900 °C. Obtained ceramic material based on CaNaPO₄ could be important for regenerative treatments of bone tissue defects. Full article

Stay-in-Place (SiP) formworks obviate the transportation, placement, removal and storage requirements of conventional formworks. Fibre Reinforced Polymer SiPs (FRP-SiP) have additional advantages, such as corrosion resistance, high specific strength and durability. This paper discusses an experimental instigation consisting of two sets of slabs having varying span-to-depth ratios cast on an FRP-SiP. Control specimens with conventional steel bar reinforcements were also cast. Several treatments for improving interfacial bonds at the interface between concrete and FRP-SiP have been investigated. Cyclic flexural tests were performed to evaluate their structural performance. Load-displacement relationship and load capacity are presented. Failure envelopes and energy absorption capacity were evaluated. It was found that the load capacity of FRP-SiP was around 107% greater than the conventional steel rebar specimens. Bond treatment on the FRP-SiP specimens increased the load capacity by around 215% over the untreated specimens. The load-deflection behaviour and the failure modes of the FRP-SiP specimens were distinctly different from those of the conventional specimens. The flexure and shear provisions in American Concrete Institute Standards (ACI 440) were found to be conservative in comparison to the present results. This study demonstrates that FRP-SiPs improve both the structural performance and construction efficiency of concrete slabs, however, new standards would be necessary to be able to utilize their improved capacity. Full article

Carbon fiber reinforced polymers (CFRPs) have spread to a wide range of industries in recent decades, including the automobile, aeronautics, and space industries. Recently, the emergence of new requirements for improved properties and features has become one of the major drivers of the introduction of innovative methodologies and process optimization. In this study, the effect of nanomaterials on the behavior of carbon fiber-reinforced polymer (CFRP) composites was investigated experimentally. The grafting of TiO2 and SiC nanomaterials onto the surface of fibers was performed by mixing nanomaterials in the epoxy resin. CFRPs were manufactured using vacuum assisted resin transfer molding (VARTM) in this study and characterized using mechanical and thermal testing. The primary test parameters were carbon fiber with epoxy resin and 0% nanomaterials by weight. An increase in properties was observed in nanocomposite with 2% wt. of nanomaterials when compared with 0, 0.5, and 1% wt. Between 0 wt.% and 2 wt.%, the tensile strength, flexural strength, impact strength, hardness, and HDT properties were increased by 17%, 39%, 32%, 14% and 21%, respectively, due to the addition of nanomaterials into the resin. Full article

An activated charcoal with a high surface area of 4320–3800 m²/g with significant adsorption properties was prepared by the chemical and thermal processing of walnut residues. Iraqi walnut shells were sonicated with different ratios of potassium hydroxide (KOH). The mixture was then calcined at different temperatures using an electric oven until the best thermal conditions for a very high activated surface area and performance were identified. The resulting activated charcoal was further purified to remove residual KOH and metal impurities. Investigations revealed that the quality of the prepared activated charcoal was comparable to or surpassed that of commercially available counterparts in both the physical and adsorption properties. It was characterised for methylene blue degradation and the removal of heavy elements during water purification. Full article

Hybrid carbon and glass fiber-reinforced composites have attracted significant research interest for primary load-bearing structural components in the field of aviation manufacturing owing to their low weight and high strength to weight ratio. However, the anisotropic and heterogenic nature of carbon and/or glass fiber-reinforced composite prevents high machining quality due to the directionality effect of fibers in the polymer matrix. As such, this study investigates the effect of drilling process for hybrid fiber-reinforced composite and reports optimal drilling parameters to improve the drill quality. Experimental studies indicate that an increased point angle (i.e., from 80° to 120°) resulted in low delamination upon entry due to reduced thrust force, which in turn produces better surface finish with minimal tool wear. The optimal feed rate (0.2 mm/min) ensures lower delamination at entry, since higher feed rates can increase the thrust force due to elevation in the shear area or raise the self-generated feed angle, which in turn reduces the effective clearance angle. To this end, drilling parameters were optimized using Dandelion optimizer (DO)—a cutting-edge metaheuristic search algorithm (MSA). We report the excellent consistency of DO to solve the proposed drilling optimization problem while achieving promising results as ascertained by the small standard deviation values. Full article

The industrial use of additive manufacturing continues to rapidly increase as new technology developments become available. The Arburg plastic freeforming (APF) process is designed to utilize standard polymeric granules in order to print parts with properties similar to those of molded parts. Despite the emerging industrial importance of APF, the current body of knowledge regarding this technology is still very limited, especially in the field of biodegradable polymer composites. To this end, poly(lactic acid) (PLA) was reinforced with halloysite nanotubes (HNTs) by hot melt extrusion. The PLA/HNT (0–10 wt%.) composites were analyzed in terms of their rheology, morphology, and thermal and mechanical properties. A study of the processing properties of these composites in the context of APF was performed to ensure the consistency of 3D-printed, high-quality components. The optimized machine settings were used to evaluate the tensile properties of specimens printed with different axis orientations (XY and XZ) and deposition angles (0 and 45°). Specimens printed with an XY orientation and deposition angle starting at 0° resulted in the highest mechanical properties. In this study, the use of PLA/HNT composites in an APF process was reported for the first time, and the current methodology achieved satisfactory results in terms of the 3D printing and evaluation of successful PLA/HNT composites to be used as feedstock in an APF process. Full article

The present paper continues the exploration of the physicochemical and catalytic properties of vanadia-mayenite composites. The samples were prepared by an impregnation of calcium aluminate Ca₁₂Al₁₄O₃₃ (mayenite, C12A7) with a solution of vanadium precursor. Pure mayenite and V/C12A7 nanocomposites were characterized by Raman and diffuse reflectance UV–Vis spectroscopies. The reducibility of the samples was examined in temperature-programmed reduction experiments performed in a hydrogen atmosphere. The catalytic performance of vanadium-containing systems was studied in the non-oxidative dehydrogenation of ethane. As found, the low-loaded sample (5%V/C12A7 sample) contains vanadium predominantly in the form of Ca₃(VO₄)₂, while for the 10%V/C12A7 sample, two types of calcium vanadates (Ca₂V₂O₇ and Ca₃(VO₄)₂) are registered. The presence of these phases defines the spectroscopic characteristics and the redox properties of nanocomposites. Both the samples, 5%V/C12A7 and 10%V/C12A7, exhibit comparable catalytic activity, which is mainly connected with the amount of the Ca₃(VO₄)₂ phase. The uniqueness of the studied catalysts is their excellent tolerance toward coke formation under the reaction conditions. Full article

Green synthesis has recently attracted extensive attention from scientists all over the world for the production of metal nanoparticles. Selenium nanoparticles (Se NPs) have been demonstrated as a suitable supplement nutrient for the replacement of selenium ions in terms of safety and efficiency. This work presented a friendly and facile approach to synthesize the Se NPs using polyphenols content in the Cleistocalyx operculatus (CO) leaves extract. The synthesizing conditions were optimized to obtain the Se NPs with uniform distribution and shape. The prepared Se NPs were well-characterized using scanning electron microscopy, X-ray diffraction, energy diffractive spectroscopy, and Fourier-transform infrared spectroscopy. The resultant Se NPs were in spherical shape with the particle size in a range from 50–200 nm. The antimicrobial properties of Se NPs were investigated against Echerichia coli and Staphylococcus aureus, which showed reasonable activity. The acute oral toxicity of Se NPs in mice was also studied. The result indicated that Se NPs exhibited lower toxicity than that of SeO₂ with the lethal concentration (50% death of mice) of 7.75 mg kg⁻¹_. Full article

This paper presents results of specific cases of sequential exposure of wet layup ambient cured carbon/epoxy composites to thermal aging and immersion in deionized water. Thermal aging is conducted at temperatures between 66 °C and 260 °C for periods of time up to 72 h whereas immersion is up to 72 weeks. Effects are characterized in terms of moisture kinetics using a two-stage diffusion model, and through short beam shear (SBS) strength. The response is characterized by a competition between the mechanisms of postcure, which results in increased polymerization and increases in SBS strength and glass transition temperature; and thermally induced microcracking and polymer degradation as well as moisture-induced plasticization and hydrolysis accompanied by fiber-matrix debonding, which results in deterioration. Thermal aging by itself is not seen to negatively impact SBS strength until the highest temperatures of exposure are considered in the investigation. However, the subsequent immersion in deionized water is seen to have a greater deteriorative effect with the period of post-thermal aging immersion being the dominant deteriorative factor. Full article

The Delamination Threshold Load (DTL) is a key parameter representing damage resistance of a laminate and is normally identified by locating a sudden drop in the impact force-time history for the laminate made of unidirectional layers. For the woven composite, however, their failure mechanisms appear different and the current literature is not providing any clear procedure regarding the identification of the delamination initiation, as well as the evolution of the failure mechanisms associated with it. In this paper, experimental data have been collected using woven glass and carbon fiber composites. The results are analyzed in terms of force-time and force-displacement curves. While delamination and other damages were clearly observed using ultrasonic scans, the analysis of the results does not reveal any trend changes of the curves that can be associated with the incipient nucleation of delamination. A preliminary discussion regarding the nature of the mechanisms through which the delamination propagates in woven composite and a justification for the absence of a sudden change of the stiffness have been presented. It raises a question on the existence of DTL for woven composites under low velocity impact. Full article

This study attempted to harness the dual benefit of adsorption and photocatalytic degradation for efficiently removing a model anionic azo dye, Orange G, from an aqueous solution. For this purpose, a series of bifunctional nanohybrids containing different proportions of naturally occurring biopolymer chitosan and ternary photocatalyst made of kaolinite, TiO₂, and ZnO were prepared through the dissolution of chitosan in acid and subsequent deposition on ternary photocatalyst. The characterization through Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and energy dispersive X-ray spectrum (EDS) have confirmed the successful fabrication of nanohybrids from TiO₂ and chitosan. The adsorptive separation of Orange G from the aqueous solution and subsequent degradation under solar irradiation was thoroughly studied by recording the λ_max value of dye in the ultraviolet–visible (UV-Vis) spectrophotometer at various operating conditions of pH, dye concentration, contact time, and compositional variation. The nanohybrid (TP_0.75CS_0.25) fabricated from 75% ternary photocatalyst (w/w) and 25% chitosan (w/w) removed 97.4% Orange G within 110 min at pH 2.5 and 10 mg/L dye concentration. The relative contribution of chitosan and ternary composite on dye removal was understood by comparing the experimental results in the dark and sunlight. Recyclability experiments showed the suitability of the nanohybrid for long-term repeated applications. Equilibrium experimental data showed a better correlation with the Langmuir isotherm and pseudo-second-order kinetic model. The rapid and nearly complete removal capacity, long-term reusability, and simple fabrication technique make this novel nanohybrid a promising advanced material for removing hazardous azo dyes from industrial effluents. Full article

Nickel silicide nanoparticles were prepared in situ on carbon nanofibers through pyrolysis of electrospun fibers containing poly(acrylonitrile) (PAN, carbon fiber precursor), silazane (SiCN ceramic precursor), and nickel chloride (nickel source). SiCN ceramics produced in carbon nanofibers during the pyrolysis expanded the graphitic interlayer spacing and facilitated the diffusion of metal atoms to the fiber surfaces, leading to the formation of nickel silicide nanoparticles at a reduced temperature. In addition, nickel silicide nanoparticles catalyzed an in situ formation of carbon nanotubes, with carbon sourced from the decomposition of silazane. The method introduces a simple route to produce carbon supported metal nanoparticles for catalysis and energy storage applications. Full article

Bolted connections are widely adopted in steel structures and their behaviour affects to a large extent the global response of the system. High-strength bolts of type HV are commonly employed. Under pure tension, these bolt assemblies usually fail by thread stripping. However, it was observed experimentally that, under combined tension and bending, the failure mode changes to fracture of the shank. The former loading condition commonly occurs in the case of thick extended end plate connections and the latter in the case of flush end plates. In order to analyse the behaviour of the structure, the finite element method (FEM) is usually employed. While there is a wealth of information on FEM modelling of bolts for standard loading conditions (e.g., tension), the authors are unaware of a model able to replicate both tension-only and combined tension and bending conditions. In this paper, a simplified approach to be used in the framework of FEM is proposed to model the behaviour of high-strength HV bolts which can replicate the failure mechanism of bolts under tension only and combined tension and bending. The bolt assembly is modelled with continuum elements, supplemented by a non-linear spring connecting the nut to the bolt shank. The spring captures the stiffness, resistance, and ductility of the bolt-to-nut threaded connection, reproducing the experimentally observed failure mode in the case of pure tension conditions. A simplified damage model is applied to the continuum finite elements used to model the bolt, which replicates shank failure under combined tension and bending as a result of large local stresses and strains occurring under these conditions. The proposed model captures with good accuracy the actual behaviour of high-strength HV bolts under tension only as well as under combined tension and bending. Full article

The primary seismic force-resisting system (SFRS) in middle- to high-rise reinforced concrete (RC) building structures often includes coupled shear walls (CSWs) and single shear walls (SSWs). These walls are designed to transfer lateral forces to the foundation and dissipate energy through the development of plastic hinges. The latter lead to residual displacement in these structural components. On the other hand, self-centering systems enable the structures to return to their initial position after severe loading or at least reduce residual displacement. The objectives of this study were, therefore, as follows: (i) to review the state of the art on shear wall self-centering techniques and retrofitting methods based on externally bonded fiber-reinforced polymer (EB-FRP); (ii) to evaluate research needs to improve the self-centering ability of shear walls using EB-FRP. Full article

In recent years, functionalized metal oxides have been gaining popularity for biomass conversion to fuels and chemicals due to the global energy crisis. This study reports a novel catalyst based on noble metal immobilization on functionalized zirconia that has been successfully used in the production of biofuel alkyl levulinates (ALs) from lignocellulosic biomass-derived levulinic acid (LA) under vapor-phase. The wet impregnation method was used to immobilize Pt-metal nanoparticles on zirconia-based supports (silicotungstic acid zirconia, STA-ZrO₂; sulfated zirconia, S-ZrO₂; and tetragonal zirconia, t-ZrO₂). A variety of physicochemical techniques were used to characterize the prepared catalysts, and these were tested under atmospheric pressure in continuous flow esterification of LA. The order of catalytic activity followed when ethyl levulinate was produced from levulinic acid via esterification: Pt/STA-ZrO₂ ≫ Pt/S-ZrO₂ ≫ Pt/t-ZrO₂. Moreover, it was found that ALs synthesis from LA with different alcohols utilizing Pt/STA-ZrO₂ catalyst followed the order ethyl levulinate ≫ methyl levulinate ≫ propyl levulinate≫ butyl levulinate. This work outlines an excellent approach to designing efficient catalysts for biofuels and value-added compounds made from biomass. Full article

Metal-nanocluster-doped porous composite materials are attracting considerable research attention, due to their specific catalytic performance. Here we report a simple, cheap, and efficient strategy for the preparation of palladium hydrogenation catalysts based on metal-organic frameworks (MOFs). It has been shown that the synthesis of Pd/MOF results in the formation of palladium nanoparticles uniformly fixed on the surface. The composition and structure of the resulting composites were studied using elemental analysis, DSC, TGA, XRD, TEM, and IR spectroscopy. Pd nanoparticles with an average diameter of 8–12 nm were successfully confined in the UiO-type MOFs, and the obtained nanocomposites exhibited abundant porosity, high stability, and a large surface area. It has been shown that the resulting catalytic systems with high activity, selectivity, and stability reduce phenylacetylene and allyl alcohol to styrene and propanol, respectively, in liquid-phase hydrogenation reactions. Full article

Development of eco-friendly and biodegradable package materials is an important goal of modern science and international industry. Poly(lactic)-co-glycolic acid (PLGA) is suitable for this purpose. However, biocompatible materials may be contaminated with bacteria. This problem may be solved by the addition of metal oxides nanoparticles (NPs) with antibacterial properties. Although metal oxides NPs often show cytotoxicity against plant and mammalian cells, a new nanocomposite based on PLGA and aluminum oxide (Al₂O₃) NPs has been developed. The PLGA/Al₂O₃ NP composite has pronounced antibacterial properties. The addition of Al₂O₃ NPs 0.01% inhibited growth of E. coli for >50%. The antimicrobial effect of Al₂O₃ NPs is implemented through the generation of reactive oxygen species and damage of bacterial proteins and DNA. The biocompatibility of the nanocomposite with plant and mammalian cells was studied. The PLGA/Al₂O₃ NP composite did not influence the growth and development of tomatoes and cucumbers. PLGA and its composite with Al₂O₃ NPs 0.001–0.1% did not influence viability and proliferation of mammalian cells, on their density or substrate colonization rate. The developed nanocomposite has controlled mechanical properties, high antibacterial activity and high biocompatibility, which makes it an attractive candidate for building and food package material manufacture and agriculture. Full article

At present, most carbon fibres are used as reinforcement for polymers. Fabrication technologies for carbon-fibre-reinforced polymers (CFRPs) are now reaching a mature state that effectively replaces metals in various technical fields, including aerospace, sporting equipment, civil engineering, etc. However, there are many structures in which metal alloys cannot be replaced with CFRPs because of, firstly, the limited temperatures that plastics can survive, and secondly, the relatively low fracture toughness of CFRPs. This has led researchers to develop carbon-fibre/metal-matrix composites (CFMMCs), considering aluminium, titanium, and nickel alloys as potential matrix materials. The present paper presents a review of the corresponding results, focusing on those obtained in the current century. Full article

The use of high thermal conductive materials for heat transfer is gaining attention as a suitable treatment for improving battery performance. Thermal runaway is a relevant issue for maintaining safety and for proficient employment of accumulators; therefore, new solutions for thermal management are mandatory. For this purpose, a hierarchical nanomaterial made of graphite nanoplatelet has been considered as an interface material. High-content graphite nanoplatelet films have very high thermal conductivity and might improve heat dissipation. This study investigates the effect of a thermally conductive material as a method for safety enhancement for a battery module. A numerical model based on the finite element method has been developed to predict the heat generation during a battery pack’s charge and discharge cycle, using the Multiphysics software Comsol. The lumped battery interface generates appropriate heat sources coupled to the Heat Transfer Interface in 3D geometry. Simulation results show that the protection of neighbouring cells from the interleaved layer is fundamental for avoiding heat propagation and an uncontrollable heating rise of the entire battery pack. The use of graphite nanocomposite sheets could effectively help to uniform the temperature and delay the TR propagation. Full article

For several years, the aviation industry has seen dynamic growth in the use of composite materials due to their low weight and high stiffness. Composites are being considered as a means of building lighter, safer, and more fuel-efficient automobiles. Composite materials are the building material of a relatively new kind of unmanned aerial vehicle, commonly known as a drone. Incremental forming methods allow materials to be quickly formed without the need to manufacture conventional metal dies. Their advantage is the high profitability during the production of prototypes and a small series of products when compared with the conventional methods of plastic forming. This article provides an overview of the incremental forming capabilities of the more commonly produced aluminium- and titanium-based laminates, which are widely used in the aircraft industry. In addition, for composites that are not currently incrementally formed, i.e., aramid-reinforced aluminium laminates, the advantages and potential for incremental forming are presented. Full article

The combination of awareness of harmful industrial processes, environmental concerns, and depleting petroleum-based resources has spurred research in developing sustainable materials from renewable sources. Natural bio-based polymers have replaced synthetic polymers because of growing concern about environmental sustainability. As a result of heating and distilling cashew nutshell liquid (CNSL), cardanol has emerged as a promising bio-retrieved component that can be used to make bio-based epoxy. The current work intends to investigate the mechanical properties of three kinds of cardanol-based bio-based epoxies in anticipation of widespread use. Vickers hardness, tensile and flexural strength are used to characterize mechanical properties. Additionally, a water absorption test is carried out to examine the weight gain properties of all the bio-based epoxy variants selected. FormuLITE 2 (FormuLITE 2501A + FormuLITE 2401B) exhibited the highest Vickers hardness, tensile and flexural strength among the three variants. Moreover, it exhibited a water absorption rate nearly equivalent to that of the conventional LY556/HY951, and thus, FormuLITE 2, the bio-based epoxy resin having 34% of bio-content blended with conventional epoxy, proves to be the best option out of the selected bio-based epoxies to be used further as the matrix material for the fabrication of biocomposites. Full article

Geopolymer is an emerging material alternative to Portland cement and has potential as a refractory material. Adding filler in geopolymer material is a strategy to increase the advantages of its physical and mechanical properties. It has been previously reported that adding nanoparticles can increase the compressive strength value, but there is no reported interaction between nanoparticles and geopolymer during the geopolymerization process. This study aims to study the effect of adding nano-zirconia fillers on the physical and mechanical changes of metakaolin-based geopolymers with nano-zirconia fillers. The geopolymer samples were made with 100 g of metakaolin as the base material and nano-zirconia in amounts of 2 g, 5 g, 10 g, and 15 g. Further characterization was carried out by XRD, FTIR, and SEM-EDX. This study showed that the compressive strength of the MZr05 sample increased significantly by 58.7% compared to the control sample. The test results of the structure and functional groups did not lead to any new compounds formed in the geopolymerization reaction. Therefore, the interaction of metakaolin geopolymer with nano-zirconia only creates an interfacial bonding. Full article

Recently, short basalt fibres (BFs) have been gaining considerable attention in the building materials industry because of their excellent mechanical properties and lower production cost than their counterparts. Reinforcing geopolymer composites with small volumes of fibres has been proven an efficient technique to enhance concrete’s mechanical properties and durability. However, to date, no study has investigated the effect of basalt fibers’ various lengths and volume content on self-compacted geopolymer concrete’s fresh and mechanical properties (SCGC). SCGC is prepared by mixing fly ash, slag, and micro fly ash as the binder with a solid alkali-activator compound named anhydrous sodium metasilicate (Na₂SiO₃). In the present study, a hybrid length of long and short basalt fibres with different weight contents were investigated to reap the benefits of multi-scale characteristics of a single fibre type. A total of 10 mixtures were developed incorporating a single length and a hybrid mix of long (30) mm and short (12) mm basalt fibres, with a weight of 1%, 1.5% and 2% of the total binder content, respectively. The fresh and mechanical properties of SCGC incorporating a hybrid mix of long and short basalt fibres were compared to plain SCGC and SCGC containing a single fibres length. The results indicate that the hybridization of long and short fibres in SCGC mixture yields better mechanical properties than single-length BF-reinforced SCGC. A hybrid fibre coefficient equation will be validated against the mechanical properties results obtained from the current experimental investigation on SCGC to assess its applicability for different concrete mixes. Full article