Journal of Composites Science

The unique physical and chemical properties of composite materials based on carbon nanofibers (CNFs) makes them attractive to scientists and manufacturers. One promising method to produce CNFs is catalytic chemical vapor deposition (CCVD). In the present work, a method based on carbon erosion (CE) of bulk microdispersed Ni-Cu alloys has been proposed to prepare efficient catalysts for the synthesis of CNF-based composites. The initial Ni-Cu alloys were obtained by mechanochemical alloying (MCA) of metallic powders in a planetary mill. The effect of MCA duration on the phase composition of Ni-Cu samples was studied by X-ray diffraction analysis and temperature-programmed reduction in hydrogen. It has been also revealed that, during such stages as heating, reduction, and short-term exposure to the reaction mixture (C₂H₄/H₂/Ar) at 550 °C, the formation of a Ni-based solid solution from the initial Ni-Cu alloys takes place. The early stages of the CE process were monitored by transmission electron microscopy combined with energy-dispersive X-Ray analysis. It was found that the composition of the catalytic particles is identical to that of the initial alloy. The morphological and structural features of the prepared Ni-Cu-CNF composites were studied by scanning and transmission electron microscopies. The textural characteristics of the composites were found to be dependent on the reaction time. Full article

Infectious diabetic wounds can result in severe injuries or even death. Biocompatible wound dressings offer one of the best ways to treat these wounds, but creating a dressing with a suitable hydrophilicity and biodegradation rate can be challenging. To address this issue, we used the electrospinning method to create a wound dressing composed of poly(glycerol sebacate) (PGS) and gelatin (Gel). We dissolved the PGS and Gel in acetic acid (75 v/v%) and added EDC/NHS solution as a crosslinking agent. Our measurements revealed that the scaffolds’ fiber diameter ranged from 180.2 to 370.6 nm, and all the scaffolds had porosity percentages above 70%, making them suitable for wound healing applications. Additionally, we observed a significant decrease (p < 0.05) in the contact angle from 110.8° ± 4.3° for PGS to 54.9° ± 2.1° for PGS/Gel scaffolds, indicating an improvement in hydrophilicity of the blend scaffold. Furthermore, our cell viability evaluations demonstrated a significant increase (p < 0.05) in cultured cell growth and proliferation on the scaffolds during the culture time. Our findings suggest that the PGS/Gel scaffold has potential for wound healing applications. Full article

An innovative simultaneous process, using supercritical fluid (SCF) chemistry, was used to recycle uncured prepregs and to functionalize the recovered carbon fibres with Fe₃O₄ magnetic nanoparticles (MNPs), to produce a new type of secondary raw material suitable for composite applications. This specific functionalization allows the fibres to be heated by induction through a hysteresis loss mechanism characteristic for nanoparticle susceptor-embedded systems, for triggered healing properties and a potentially easy route for CF reclamation. Using SCF and hydrothermal conditions for recycling, functionalization of fibres can be performed in the same reactor, resulting in the creation of ready-to-use fibres and limiting the use organic solvent. After cutting the uncured prepreg to the desired length to fit in future applications, supercritical CO₂ extraction is performed to partially remove some components of the uncured prepreg matrix (step 1). Then, the recycled carbon fibres (rCFs), still embedded inside the remaining organic matrix, are brought into contact with reactants for the functionalization step (step 2). Two possibilities were studied: the direct synthesis of MNPs coated with PAA in hydrothermal conditions, and the deposition of already synthesized MNPs assisted by supercritical CO₂-acetone. No CF surface activation is needed thanks to the presence of functional groups due to the remaining matrix. After functionalization, ready-to-use material with homogeneous depositions of MNPs at the surface of rCF is produced, with a strong magnetic behaviour and without observed degradation of the fibres. Full article

The use of interleaving material with viscoelastic properties is one of the most effective solutions to improve the damping capacity of carbon fibre-reinforced polymer (CFRP) laminates. Improving composite damping without threatening mechanical performance is challenging and the use of nanomaterials should lead to the target. In this paper, the effect of a nanostructured interlayer based on graphite nanoplatelets (GNPs) on the damping capacity and fracture toughness of CFRP laminates has been investigated. High-content GNP/epoxy (70 wt/30 wt) coating was sprayed on the surface of CF/epoxy prepregs at two different contents (10 and 40 g/m²) and incorporated at the middle plane of a CFRP laminate. The effect of the GNP areal weights on the viscoelastic and mechanical behaviour of the laminates is investigated. Coupons with low GNP content showed a 25% increase in damping capacity with a trivial reduction in the storage modulus. Moreover, a reduction in interlaminar shear strength (ILSS) and fracture toughness (both mode I and mode II) was observed. The GNP alignment and degree of compaction reached during the process were found to be key parameters on material performances. By increasing the GNP content and compaction, a mitigation on the fracture drop was achieved (−15%). Full article

A significant amount of energy waste has accumulated in the world, in particular, large-tonnage fine ash from central heating stations (coal ash), which can negatively affect the natural environment and the health of the population. However, at the same time, due to its chemical composition, this waste can be disposed of by complex processing as a secondary mineral component, thus reducing the anthropogenic load on the natural environment. This article presents a physico-chemical study of coal ash for its further use as a secondary mineral component, in particular, a component of a raw mixture with limestone to produce a composite Portland cement clinker. Coal ash and limestone were subjected to granulometric, chemical, differential thermal, scanning electron microscopy, elemental chemical and X-ray structural analyses, as well as modeling to assess the possibility of optimizing the raw material and mineralogical composition of the composite Portland cement clinker. During the research, the chemical and elemental compositions of the coal ash and limestone were determined and SEM images of the coal ash were obtained; it was found that 68.04% of the coal ash was represented by the fraction with granules <0.16 mm. Using X-ray diffraction analysis, the main limestone minerals were identified, which were represented by calcite and silica. Based on the results of mathematical modeling of the utilization of coal ash from a thermal power plant by processing with limestone, a two-component raw material mixture containing 23.66% fly ash and 76.34% limestone was optimized and the optimal mineralogical composition of the composite Portland cement clinker was determined. Utilization of coal ash by processing as a secondary raw material can be carried out at almost any ash storage facility anywhere in the world, taking into account the chemical composition of the processed ash. It was found that the replacement of natural raw materials with man-made raw materials in the form of coal ash contributed to a reduction in fuel consumption for firing (kg of conventional fuel) by 13.76% and a decrease in the thermal effect of clinker formation by 5.063%. Full article

In order to promote the research of green energy in the situation of increasingly serious environmental pollution, dielectric ceramic energy storage materials, which have the advantages of an extremely fast charge and discharge cycle, high durability, and have a broad use in new energy vehicles and pulse power, are being studied. However, the energy storage density of ordinary dielectric ceramic ferroelectric materials is low, so, in this paper, we have divided eight components based on BaTiO₃ (BT). Through the traditional solid phase sintering method, AB positions were replaced with various elements of different proportions to improve their energy storage density and the energy storage efficiency of BT-based ferroelectric materials. In this paper, we studied the results of XRD, Raman, ferroelectric, dielectric, and impedance tests of doped samples, and the best components were determined. The (1−x)BT−xBi(${\mathrm{M}\mathrm{g}}_{1/3}{\mathrm{Z}\mathrm{n}}_{1/3}{\mathrm{T}\mathrm{a}}_{1/6}{\mathrm{N}\mathrm{b}}_{1/6}$)O₃ series of ceramics are made by the incorporation of five elements, Bi³⁺, Mg²⁺, Zn²⁺, Ta⁵⁺, and Nb⁵⁺. With the rising electric hysteresis loop of the doping amount x thin, the saturation polarization strength and residual polarization strength decrease, and the energy storage density rises first and then decreases. The dielectric characteristic after x = 0.08 showed a flat dielectric peak, indicating that the ferroelectric relaxation had been formed. The energy storage density and efficiency of the best component x = 0.12 reached 1.75 J/cm³ and 75%, respectively, and the Curie temperature was about −20 °C, so it has the potential to be used at room temperature. Full article

We propose a unique form of dye-sensitized solar cells (DSSCs), paper DSSCs based on carbon-nanotube (CNT) composite papers, and the use of a gel electrolyte for the paper DSSC. In our previous study, we succeeded in developing the paper DSSC. However, its performance and lifetime were not sufficient. We considered that the problem was the use of liquid-type electrolyte. To improve the performance of the paper DSSC, a gel electrolyte was introduced to increase safety and durability. Here, a polymer gel electrolyte was synthesized using a copolymer of polyethylene glycol (PEG) and polyvinylidene fluoride (PVDF) as a matrix, mixed with iodine and potassium iodide. The resulting paper DSSC had a fill factor (FF, a performance indicator) of 0.248 and a conversion efficiency of 2.43 × 10⁻⁵% with an extended working time (lifetime) of more than 110 min. Further modifications were made to the metallic CNT composite paper and the gel electrolyte, resulting in an increased conversion efficiency of 2.02 × 10⁻³%. This study suggests the potential of gel electrolytes in enhancing the performance of paper DSSCs, providing new insights for their future applications. Full article

Flexible supercapacitors are demanded for energy storage of wearable electronics. In this paper, a simple strategy for preparing flexible carbon fibers (CFs) with good energy storage capacity using a mixed acid treatment process is reported. When the volume ratio of concentrated sulfuric acid to concentrated nitric acid is 3:1, the carbon fiber electrodes have the best electrochemical performance with a high capacitance of 27.83 F g⁻¹ at 15 mA g⁻¹ and extremely high capacitance retention of 79.9% after 500 cycles at 100 mA g⁻¹. Furthermore, their energy density can reach 3.86 Wh kg⁻¹ with a power density of 7.5 W kg⁻¹. Such an excellent electrochemical performance of carbon fiber electrodes is attributed to their surface rich oxygen-containing functional groups, rough surface, and a certain number of graphene quantum dots (GQDs). Importantly, the all-solid-state flexible supercapacitor performs excellent bending stability performance with a capacitance retention of almost 100% after 500 times of bending at 180°, showing good prospects and applications in the field of flexible energy storage devices. Full article

The automobile industry uses magnesium for load-bearing components due to its low density, durability, and ductility. This study investigated a nanocomposite containing Nb₂O₅ (3 and 6 wt%) nanoparticles as reinforcement with AZ31 magnesium alloy made by stir casting. A severe plastic deformation was conducted on the cast samples via equal-channel angular pressing (ECAP) after homogenization at 410 °C for 24 h and aging at 200 °C for 10 h. The microstructural distributions and mechanical properties of the magnesium metal matrix composites (MMCs) reinforced with Nb₂O₅ nanoparticles were investigated via ECAP. With the increase in the number of ECAP passes, the grain sizes became uniform, and the size of secondary phases reduced in the pure Nb₂O₅/AZ31 MMC. The grain size decreased remarkably after the ECAP process from 31.95 µm to 18.41µm due to the dynamic recrystallization during plastic deformation. The mechanical properties of hardness, ultimate tensile strength, and elongation effectively improved after each ECAP pass. The maximum values achieved for the Nb₂O₅/AZ31 composite subjected to ECAP were 64.12 ± 12 HV, 151.2 MPa, and 52.71%. Full article

Based on the Hamilton principle combined with the Timoshenko beam theory, the authors developed a mixed finite element (FE) method for the nonlinear free vibration analysis of functionally graded (FG) beams under combinations of simply supported, free, and clamped edge conditions. The material properties of the FG beam gradually and smoothly varied through the thickness direction according to the power-law distributions of the volume fractions in the constituents, and the effective material properties of the FG beam were estimated using the rule of mixtures. The von Kármán geometrical nonlinearity was considered. The FE solutions of the amplitude-frequency relations of the FG beam were obtained using an iterative process. Implementing the mixed FE method showed that its solutions converged rapidly and that the convergent solutions closely agreed with the accurate solutions reported in the literature. A multilayer perceptron (MP) back propagation neural network (BPNN) was also developed to predict the nonlinear free vibration behavior of the FG beam. After appropriate training, the prediction of the MP BPNN’s amplitude-frequency relations was entirely accurate compared to those obtained using the mixed FE method, and its central processing unit time was less time-consuming than that of the mixed FE method. Full article

One of the supporting factors behind the biomolecules recently used in anti-aging and skin nourishment is their antioxidant properties. Hydrogen peroxide (H₂O₂) is a well-known small molecule oxidant that induces apoptosis in human skin fibroblast (HSF) cells through the synthesis of inflammatory cytokines. Hence, this study aimed to investigate the antioxidant activities of protein hydrolysates prepared from Iris squid (Symplectoteuthis oualaniensis) (PHCSO) in vitro. Firstly, two peptides with MWs more than 10 kDa (PHCSO-1) and less than 10 kDa (PHCSO-2) were obtained through ultrafiltration and were characterized (molecular pattern amino acid composition, FTIR) before testing the antioxidant activity (DPPH radical scavenging activity and hydroxyl radical scavenging activity). Then, the effects of PHCSOs on HSF cell viability, H₂O₂-induced oxidative stress model of HSF cells, ROS fluorescence staining, level of cytokines (IL-1, IL-6 and TNF-α) and cellular antioxidant properties (SOD activity, CAT activity, GSH and MDA content) were investigated. The cell morphology was examined through fluorescence staining and inflammatory factors and antioxidant activity analysis showed that superior properties were observed in PHCSO-2 peptide compared to PHCSO-1 and PHCSO. Among the peptides, PHCSO-2 (5 mg/mL) had higher DPPH and hydroxyl radical scavenging activities of 58% and 57%, respectively. On the other hand, the PHCSO-2 treatment reduced the TNF-α activity by 25%, which indicated the effective protection of PHCSO-2 from oxidative stress damage in the skin. These findings proved that peptides with less than 10 kDa were more suitable for therapeutic purposes, with good antioxidant properties. Accordingly, the protein hydrolysate from S. oualaniensis proved to be an excellent marine-based antioxidant peptide, which could be applied in cosmetic, pharmaceutical and food industries. Full article

This study is focused on 3D printing of polyamide 6 (PA6), PA6/graphene oxide (PA6/GO) and PA6/glass-fibre-reinforced (PA6/GF) composites. The effect of graphene oxide and glass-fibre reinforcement on 3D-printed PA6 is explored for improvement of the interfacial bond and interlaminar strength in ambient, wet and high temperature conditions relating to electric car battery box requirements. The influence of environmental conditions and process parameters on the 3D-printed polymer composites quality is also examined. Commercial PA6 filament was modified with GO to investigate the thermal and mechanical properties. The modified composites were melt-compounded using a twin-feed extruder to produce an improved 3D-printing filament. The improved filaments were then used to 3D-print test samples for tensile and compression mechanical testing using universal testing machines and thermal characterisation was performed following condition treatment in high temperature and water for correlation to dry/ambient samples. The study results show the studied materials were mostly suitable in dry/ambient conditions. PA6/GF samples demonstrated the highest strength of all three samples in ambient and high-temperature conditions, but the least strength in wet conditions due to osmotic pressure at the fibre/matrix interface that led to fibre breakage. The introduction of 0.1% GO improved the tensile strength by 33%, 11% and 23% in dry/ambient, dry/high temperature and wet/ambient conditions, respectively. The wet PA6/GO samples demonstrated the least strength in comparison to the ambient and high-temperature conditions. Notwithstanding this, PA6/GO exhibited the highest tensile strength in the wet condition, making it the most suitable for a high-strength, water-exposed engineering application. Full article

Four series of experiments were carried out to study the possibility of replacing clay and an iron-containing component with tefritobasalt and lead slag as part of the initial charge for Portland cement. The experiments were carried out at atmospheric pressure and a temperature of 1350 °C. It was shown that the replacement of clay and an iron-containing component with tefritobasalt and lead slag as part of the initial charge in the cement industry will lead to a decrease in temperature by 100 °C in the technological scheme of production and a reduction in energy consumption, since the theoretical specific consumption of raw materials is 1.481 t/t of clinker, which is approximately 70 kg lower than in traditional mixtures. The content of non-traditional components in total was 24.69%. In addition, tefritobasalts improved clinker formation processes, contributed to a decrease in the firing temperature, and intensified the clinker firing process. A small amount of lead slag (5.06%) introduced into the mixture changed the structure of the clinker and improved the process of mineral formation while also improving roasting and reducing the anthropogenic impact on the environment through the disposal of man-made waste. The strength of the experimental composite cements was tested after 7 and 28 days on small samples measuring 2 × 2 × 2 cm. The physicomechanical characteristics and structure of composite cements were studied. Full article

Polymer/graphene nanocomposites have attracted significant attention from the research community over the past two decades. In this work, nanocomposites of polystyrene-co-acrylonitrile (SAN) and graphene oxide (GO) were prepared using a solution blending method with tetrahydrofuran as the solvent. The GO loadings used were 0.1, 0.25, 0.5, and 1.0 wt.%. Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy were employed to characterize the structure and morphology of SAN/GO nanocomposites. Thermal analysis showed increases in the glass transition (T_g) and peak thermal degradation (T_d^peak) temperatures of SAN by the additions of GO, with T_g increasing by 3.6 °C and T_d^peak by 19 °C for 1.0 wt.% GO loading. Dynamic mechanical analysis revealed that the storage modulus of SAN was also enhanced with the incorporations of GO by up to 62% for 1.0 wt.% loading. These property enhancements may be attributed to a good dispersion of GO in the polymer matrix and their interfacial interactions. Full article

Many industries use huge amounts of synthetic dyes which may release into the wastewater in dyeing processes causing serious damage to aquatic life as they are recalcitrant, nonbiodegradable, stable to oxidizing agents, and toxic. Adsorption on activated carbon has been found to be a very efficient treatment method. In this work, a new adsorbent material composed of activated carbon and aluminum chloride (AC-Al) was prepared for the removal of a commercial anionic and anthraquinonic reactive dye, i.e., Reactive Black 5 (RB5) under various experimental conditions. Several parameters, such as the adsorbent’s dosage, initial RB5 concentration, pH, and contact time, were studied in order to determine the feasibility of AC-Al. According to the results, it was found that there was an increase in RB5 removal as the adsorbent’s dosage increased, especially, in pH 2 ± 0.1, where the removal rate increased, and reaching 100% by 1.0 g/L of AC-Al. Freundlich isotherm and pseudo-second-order kinetic models adequately fit the experimental data, indicating that favorable and heterogeneous adsorption occurred, closer to chemisorption. According to thermodynamics, it was found that the adsorption procedure was endothermic in nature (∆H⁰ = 62.621 kJ/mol) and spontaneous (∆G⁰ < 0), and according to the positive value of ∆S⁰ 0.0293 (kJ/mol∙K), there is an increase in random interaction between solid and liquid interfaces. Finally, the AC-Al adsorbent was successfully regenerated and reused for four cycles. Full article

This paper experimentally studied the influence of the notch shape and size on the damage evolution and failure strength (tension and torsion) of carbon fiber-reinforced epoxy matrix (CFRP) laminates. Hashin’s damage criteria were utilized to monitor the evolution of multi-damage modes, and FEM simulations were also performed by using the ABAQUS code to clarify the specific damage modes in detail as an instructive complement. The failure characteristics of all the notched samples were analyzed and compared with those without notches. The measured results presented that the existence of a variety of notches significantly impaired the load carrying capacity of CFRP laminates. The tensile strengths of C-notch and U-notch increase with an increasing notch radius, while the ultimate torques of C-notch and V-notch decrease with an increasing notch size and angle. The variation in notched properties was explained by different notch shapes and sizes, and the failure characteristics were also presented and compared among notched CFRP laminates with varied notches. Full article

Carbon fiber reinforced polymers (CFRPs) are increasingly used in the aerospace industry because of their robust mechanical properties and strength to weight ratio. A significant drawback of CFRPs is their resistance to formability when drawing continuous CFRPs into complex shapes as it tends to bridge, resulting in various defects in the final product. However, CFRP made from Stretch Broken Carbon Fiber (SBCF) aims to solve this issue by demonstrating superior formability compared to conventional continuous CFRPs. To study and validate the performance of SBCF, a statistical design of the experiment was conducted using three different types of CFRPs in tow/tape form. Hexcel (Stamford, CT, USA) IM7-G continuous carbon fiber impregnated with Huntsman (The Woodlands, TX, USA) RDM 2019-053 resin system, Hexcel SBCF impregnated with RDM2019-053 resin, and Montana State University manufactured SBCF impregnated with Huntsman RDM 2019-053 resin were tested in a multitude of forming trials and the data were analyzed using a statistical model to evaluate the forming behavior of each fiber type. The results show that for continuous fiber CFRP tows forming, Fmax and Δmax do not show statistical significance based on temperature fluctuations; however, in SBCF CFRP tows forming, Fmax and Δmax is dominated by the temperature and geometry has a low statistical influence on the Fmax. The lower dependence on tool geometry at higher temperatures indicates possibly superior formability of MSU SBCF. Overall findings from this research help define practical testing methods to compare different CFRPs and provide a repeatable approach to creating a statistical model for measuring results from the formability trials. Full article

Variation of light absorption, mainly the shift and shape of the absorption edge, are two promising approaches aimed at understanding the fundamental processes of optical transitions in crystalline and amorphous materials. This allows us to better understand the structure of energy bands. Significant advances have been made in understanding the fundamental chemical and physical properties of polymers to improve the efficiency of photovoltaic and optoelectronic devices. However, the relationship between these two properties has not been determined. Characterization of the optical properties of polymers, such as infrared dichroism, light absorption, Raman polarization, and emission spectra, is an important method for studying electronic properties. To consider conductivity and thermal savings in the range (300–500 K), we also investigate the effect of temperature on conductivity. Activation energies found in different cases were used. Ionic conductivity has been found to be temperature-dependent for all SPE formulations. It has been found that the ionic conductivity of the membrane presents two regimes, the first being at relatively low temperatures. The ionic conductivity exhibits a relatively independent behavior of temperature. It was found that the dielectric constant of the SPE polymer electrolytic system increased with increasing temperature. This behavior is typical of pole insulators because the alignment of the dipoles becomes easier with increasing temperature and thus the dielectric constant increases. Full article

This research paper focuses on investigating the thermal conductivity behavior of polymer matrix composite materials, specifically those composed of PSU and BaTiO₃, both experimentally and numerically. The thermal conductivity of composites has been studied using a variety of theoretical and semi-empirical methods. However, in cases where the filler concentration is minimal, these models provide a superior estimate. To numerically resolve the thermal heat transfer for an elementary cell, the finite element method is employed in this study. The impact of contact resistance, barium titanate percentage, and quenching temperature on the composite’s effective thermal conductivity and dynamic behavior is given consideration. The results demonstrate that the suggested numerical model is in good agreement with experimental measurements as well as Hatta–Taya and Hashin–Shtrikman’s analytical models. The results provide significant insight into the thermal conductivity behavior of composites, which can inform the development of more effective thermal management solutions for composite materials. Effective thermal management is critical for the successful application of polymer matrix composite materials in various engineering applications. Thermal conductivity is a key factor in thermal management and is influenced by factors such as the concentration of filler particles, their shape, size, and distribution, and the matrix material’s properties. Full article