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Controlled shrinkage of hydrothermal carbon coating (HTCC) during its carbonization preparation process offers a novel strategy for optimizing the interfacial properties of fiber-reinforced ceramic matrix materials. In this study, the effect of volumetric shrinkage in monolayer or bilayer HTCC on the interface characteristics and mechanical properties of C f /ZrB 2 -SiC composites is investigated. The bilayer HTCC significantly enhances the crack deflection effect within the interphase compared to the monolayer HTCC. By precisely controlling the shrinkage of the layers of the bilayer HTCC, an innovative C/SiC/C trilayer interphase was synthesized in situ during the polymer infiltration process for preparing the C f /ZrB 2 -SiC composites, which synergistically enhances stress dispersion and load transfer efficiency within the interface. The work of fracture for C f /ZrB 2 -SiC composites modified by the trilayer interphase has been significantly elevated to 2258 J/m2, which far exceeds the 129 J/m2 measured for the composites lacking a HTCC interphase. [ABSTRACT FROM AUTHOR]

This research addresses limitations in current aviation composite assembly techniques, often constrained by certification challenges. To enhance bonded composite components, open holes are frequently introduced, leading to increased vulnerability to delamination, a prominent failure mode in composite laminates. This study focuses on observing the impact of open holes on the mode II behavior of composites under various distances and hole diameter conditions. Results illustrate distinct load–displacement curves influenced by hole size, with shorter distances accelerating crack propagation, evidenced by reduced elastic regions and lower load values. Analyzing specimen appearances and crack patterns highlights stress concentration at the hole, influencing initiation and propagation. In the absence of a hole, cracks exhibit a zig-zag pattern near the loading point, while with a hole, they concentrate around it. Elastic region length varies with the pre-crack-to-hole distance, indicating accelerated crack propagation in shorter distances. This study underscores the direct influence of hole size on load values, emphasizing its pivotal role in determining composite mechanical properties. This research provides valuable insights into hole characteristics' interplay with delamination behavior in carbon fiber-reinforced composites, essential for optimizing aerospace component design and structural integrity. [ABSTRACT FROM AUTHOR]

We report a CNT/eGaIn composite that suppresses dissolutive wetting on platinum, maintaining interconnect stability for up to 30 days. Minimizing CNT aggregation prevents gallium penetration, enhancing the reliability of liquid metal components in electronics. [ABSTRACT FROM AUTHOR]

In this manuscript the low velocity impact resistance of a novel multilayered energy absorbing structure was studied and compared to the materials used in US Army Advanced Combat Helmets. We investigate the dynamic performance of 3D printed lattice structures sandwiched between carbon fiber composites and Kevlar fabrics to develop helmets that are lighter and have better blast protection. The energy absorbed by the sandwich structure was recorded based on the difference in acceleration between the top impacted surface and the base of the structure. A multi degree of freedom non-linear spring mass model was used to predict the response of the multilayer sandwich structures. Nonlinear stiffness values were determined through compression experiments. A good agreement between the model and the experiment at the measured boundary allows for better understanding of the material layers and provides a modeling framework for future predictions and optimization efforts. This study provides insights into the use of digitally 3D printed cellular materials, carbon fiber composites, and Kevlar fabrics to provide superior impact performance at a lighter weight compared to existing helmet systems. [ABSTRACT FROM AUTHOR]

Effective lightning strike protection for critical aerospace and wind applications requires high electrical conductivity to dissipate current efficiently. However, polymer matrix composites face a challenge due to their inherently insulating nature. While conventional carbon fiber-reinforced composites (CFRP) exhibit electrical conductivity in the planar direction, achieving through-thickness conductivity remains an ongoing challenge. In this work, we have undertaken the fabrication of CFRP interleaved with vertically oriented carbon fibers (Z-fiber) to impart higher electrical conductivity along the thickness direction. Two Z-fiber composite variations are prepared: Z-1 with a single layer of Z-fiber and Z-5 with five interleaved layers and compared with no Z-fiber layer (Z-0) composite. The composite panels were subjected to lab-scale lightning strike tests with a current magnitude of 100 kA. To emulate real-world service conditions, an aerospace-grade paint coating was applied to the composite laminates. Comparative analysis shows Z-1 reduces damage diameter to ∼22 mm compared to Z-0 (∼26 mm), while Z-5 exhibits the least damage (∼16.7 mm), confirmed by optical microscopy. Z-5 demonstrates nine times higher through-thickness electrical conductivity than Z-0, reducing electrical anisotropy substantially. Thermal-electric finite element damage modeling predicts surface damage within 6% of experimental values for both Z-0 and Z-5 composites. Flexural tests post-lightning reveal Z-5 retains 66% flexural strength and 86% modulus, significantly better than Z-0, which retains less than 40% for both properties. This study highlights the efficacy of Z-fiber composites in lightning strike protection, offering improved through-thickness conductivity and mechanical property retention. [ABSTRACT FROM AUTHOR]

Manganese oxide/nitrogen-doped carbon composite nanoparticles (MnO-N/C NPs) for magnetic resonance imaging (MRI)-guided photothermal-enhanced catalytic therapy and photothermal therapy for hepatocellular carcinoma using near-infrared light to modulate multiple enzyme activities. [Display omitted] Nano-enzymatic catalytic therapy has been widely explored as a promising tumor therapeutic method with specific responsiveness to the tumor microenvironment (TME). However, the inherent lower and simplex catalytic efficiency impairs their anti-tumor efficacy. Therefore, developing novel nanozymes with relatively high and multiple catalytic characteristics, simultaneously enhancing the enzyme-like activity of nanozymes using the proper method, photothermal promoted catalytic property, is a reliable way. In this paper, we report a manganese oxide/nitrogen-doped carbon composite nanoparticles (MnO-N/C NPs) with multi-enzyme mimetic activity and photothermal conversional effect. The peroxidase (POD)-like/oxidase (OXD)-like/catalase (CAT)-like activity of MnO-N/C nanozymes was accelerated upon exposure to an 808 nm NIR laser. In vitro and in vivo results proved that the MnO-N/C NPs shown excellent magnetic resonance imaging (MRI) guided synergistic photothermal-enhanced catalytic treatment and photothermal therapy of liver cancer. The photothermal enhanced multi-enzyme activity maximizes the efficacy of catalytic and photothermal therapy while reducing harm to healthy cells, thereby offering valuable insights for the development of next-generation photothermal nanozymes to enhance tumor therapy. [ABSTRACT FROM AUTHOR]

This article presents a novel investigation of the free vibration behavior of functionally graded carbon nanotube-reinforced composite (FG-CNTRC) plates under hygrothermal environments. It explores both uniform and non-uniform (functionally graded) distributions of CNTs across the plate thickness for the first time. The effective material properties of the CNTRC, considering temperature and moisture dependence, are determined using the extended rule of mixture. First-order shear deformation theory (FSDT) is employed to derive the governing equations incorporating hygro-elastic and thermo-elastic relations. These equations are solved using the finite element method. A validation study verifies the accuracy of the employed approaches. Subsequently, a comprehensive parametric study investigates the influence of plate geometry (length-to-width and width-to-thickness ratios), CNTs volume fraction, boundary conditions, linear and non-linear CNTs distributions, and hygrothermal environments on the free vibration behavior of polymeric nanocomposite plates reinforced with CNTs fillers is conducted. The results reveal that the increase in temperature and moisture leads to a decrease in the effective stiffness of the FG-CNTRC plates. [ABSTRACT FROM AUTHOR]

Composite nanobeams with carbon nanotube (CNT) reinforcement are crucial components in various applications due to their unique mechanical and thermal properties. The present work investigates the frequency–aspect ratio relationship in composite nanobeams with CNT reinforcement, particularly under varying temperatures, magnetic field strengths, and Winkler elastic stiffnesses. The non-dimensional frequency variation with aspect ratio, influenced by temperature differences, reveals distinct behavior patterns. The introduction of a magnetic field alters frequency characteristics, with uniform distribution (UD) nanobeams displaying higher frequencies. The impact of Winkler elastic stiffness, temperature differences, and magnetic field strengths on frequency elucidates differing responses between UD, X -type distribution (XD), and V -type distribution (VD) nanobeams. Nonlocal strain gradient theory proves essential in capturing dynamic characteristics influenced by CNT distribution. These findings shed light on the intricate dynamics of composite nanobeams, providing valuable insights for the design of future nano-devices employing CNT-reinforced composite beams as fundamental elements. [ABSTRACT FROM AUTHOR]

Multifunctional CDs doping enhances the properties of CDs/ZIS/PAN nanofiber membrane: increased the hydrophilicity, promoted the light absorption, facilitated the transfer of photogenerated electrons. [Display omitted] Recent progress in the co-spinning of nanofibers and semiconductor particles offers a promising strategy for the development of photocatalytic devices, solving aggregation and catalyst recovery challenges. However, composite photocatalysts based on nanofiber membranes often suffer from poor conductivity, low hydrophilicity, and easy recombination of photogenerated electron-hole pairs in the semiconductor components. Here, to tackle the aforementioned issues of ZnIn 2 S 4 /polyacrylonitrile (ZIS/PAN) nanofiber-based catalysts, we prepared a composite carbon dots/ZnIn 2 S 4 /polyacrylonitrile (CZP) nanofiber membrane by blending carbon dots (CDs) with ZIS/PAN using the electrospinning process. The hydrogen evolution performance of the CZP photocatalyst was significantly improved by CDs, which enhanced the hydrophilicity, increased the light absorption, facilitated the transfer of photogenerated electrons, and reduced the recombination of photogenerated electron-hole pairs. Notably, the optimal CZP photocatalyst achieved a hydrogen evolution rate of 2250 μmol g-1h−1, which is about 23 % higher than that of the nanofiber membrane without CDs and 4.55 times higher than that of ZIS particles. The present work successfully improved the CZP nanofiber membrane of photocatalytic hydrogen evolution performance, and the membrane may benefit further device development by eliminating the need for stirring and simplifying the recovery process. [ABSTRACT FROM AUTHOR]

A 3D and top-tangled composite material (CP/NiCo-LDH-BDC) with adjustable layer spacing grown on micro-sized carbon was designed and synthesized by in-situ construction route and organic ligand intercalation method. The composed asymmetric supercapacitor has excellent electrochemical properties in different bending states, demonstrating its application potential in flexible energy storage devices. [Display omitted] • The CP/NiCo-LDH-BDC(0.03) electrode exhibits high capacitance of 1530 F g−1 (212.5 mAh/g) and excellent cycle life (88.36 % after 5000 cycles). • CP/NiCo-LDH-BDC(0.03)//CP asymmetric supercapacitor provides a high energy density of 43.7 Wh kg−1 at 800 W Kg−1. • The assembled flexible CP-LDH-BDC//CP ASC devices have excellent mechanical flexibility. Binary layered double hydroxides (LDHs) are an emerging class of materials for supercapacitors owing to their tunable topological structure and excellent theoretical energy storage capacity. However, aggregation and restacking cause a decrease in the interlayer distance of LDHs, resulting in a considerable drop in real specific capacitance. To address this, large-sized anions are intercalated into the interlayer space. Herein, we constructed 3D top-tangled NiCo-LDH nanobranches in situ on a biomass micro-sized carbon plate (CP). By varying the amount of benzene-1,4-dicarboxylic acid (BDC), we prepared a BDC-intercalated CP/NiCo-LDH composite material with adjustable interlayer spacing. Remarkably, the CP/NiCo-LDH-BDC(0.03) composite exhibited excellent electrochemical properties (1530 F g−1/212.5 mAh/g at 1 A/g). It retained 88.36 % capacity after 5000 charge–discharge cycles. The constructed CP/NiCo-LDH-BDC(0.03)//CP asymmetric supercapacitor showed excellent gravimetric capacitance (123 F g−1/54.7 mAh/g at 1 A/g) and energy density (43.7 Wh kg−1 at 800 W kg−1). Furthermore, two asymmetric capacitors connected in series powered a small lightbulb for 2 min, even in a bent state. These findings show that the fabricated CP and CP/NiCo-LDH-BDC(0.03) electrode materials can be applied in flexible and wearable energy storage systems. [ABSTRACT FROM AUTHOR]

To improve the ablation resistance of carbon/carbon (C/C) composites, ZrB 2 -SiC coatings sprayed with Pr 6 O 11 core–shell-structured ZrB 2 -SiC powders were prepared via atmospheric plasma spraying. The phase composition, microstructure, infrared radiative performance, and ablation resistance of the powders and coatings were investigated. The results show that the Pr 6 O 11 shell is uniformly distributed around the induction plasma spheroidization-treated (IPS) ZrB 2 -SiC powder and reduces the formation of low-emissivity phases, such as ZrO 2 and SiO 2 , induced by oxidation during spraying. Stripe-shaped Pr 6 O 11 appears in the coatings as a sealing phase, and the emissivity of the modified coating improves due to the high emissivity of Pr 6 O 11. When the molar percent of Pr 6 O 11 is 10 %, the coating indicates the highest emissivity (i.e. 0.94) in the 3–6 μm band at 750 °C. During a 60 mm-180 s oxyacetylene torch test, the surface temperature of the coating modified with 10 % Pr 6 O 11 decreases by 150 K and reaches 1923 K owing to its high emissivity, resulting in minimal volatilization in the sealing phase. Furthermore, the mass ablation and linear ablation rates of the coating above are 1.67 × 10−4 g/s and 1.82 × 10−4 mm/s, respectively, which are 34 % and 42 % lower than those of unmodified coating. These results confirm that the introduction of Pr 6 O 11 can increase the emissivity of the coating in the 3–6 μm band and provide considerable ablation protection for the C/C composites. [ABSTRACT FROM AUTHOR]

A hierarchical Si material combined with porous hard carbon and soft carbon composite was proposed as anode material for LIBs. The micro-hard carbon is employed to improve tap density and provide support for nano-Si and a soft carbon layer is introduced to encapsulate the nano-Si and relieve its volume change. [Display omitted] • A hierarchical Si material combined with porous hard carbon and soft carbon composite was proposed as anode material for LIBs. • The micro-hard carbon is employed to improve tap density and provide support for nano-Si to maintain stability during cycling. • The nano-Si is used to achieve a high ICE and a soft carbon layer is used to encapsulate nano-Si and relieve volume change. • In a PHC@Si@SC||NCM811 full cell, the capacity retention is 55% after 100 cycles with a harsh N/P ratio of 1.1. Silicon (Si) is considered as one of the most potential commercial materials for the next-generation lithium-ion batteries (LIBs) owing to its high theoretical capacity and low voltage platform. However, the severe volume expansion and poor electric conductivity of Si anodes limit the practical application. Herein, a hierarchical porous hard carbon@Si@soft carbon (PHC@Si@SC) material was prepared by a chemical vapor deposition (CVD) and following calcination process. The differences in capacities and initial Coulombic efficiencies (ICEs) resulting from variations in silane deposition are demonstrated using PHC@Si as a model. To improve the cycling performance, a cheap pitch-derived soft carbon was introduced to protect the nano-Si to suppress the volume expansion. The formed PHC@Si@SC anode delivers a high capacity of 1625 mAh g−1 and a high ICE of 86.8%, attributed to the excellent cooperation of hard and soft carbon. The capacity retention is 55% after 100 cycles with a harsh N/P ratio of 1.1 in a PHC@Si@SC||NCM811 full cell. This work provides a strategy, which is easy to scale up for practical application. [ABSTRACT FROM AUTHOR]

A continuous production prototype for scaling up the synthesis of a graphene oxide/multi-walled carbon nanotubes (GO/MWCNTs) composite as a hydrogen storage material has been proposed in this study. This prototype consists of an automatic feeding and mixing step wherein KMnO4 and graphite are individually fed into concentrated H2SO4 and then mixed to form a graphite/oxidant mixture. Following this, the oxidation step involves oxidizing the graphite/oxidant mixture through two-step oxidation to produce a graphene oxide dispersion. Then, the composite synthesis step includes mixing, sonicating, and stirring the graphene oxide dispersion with a sonicated dispersion of MWCNTs to obtain the final product. As a result, the morphology and structure of the GO/MWCNTs composite synthesized by the large-scale method exhibit high similarity to those of the gram-scale sample. The GO/MWCNTs exhibited a 3D nanostructure composed of MWCNTs linked to the graphene oxide layers. The hydrogen storage test results, simulated to practical hydrogen storage tanks with large amounts of adsorbents, indicated that the hydrogen storage capacity of GO/MWCNTs can reach 3.1 wt% at ambient temperature and 50 bar. The analysis of life cycle impacts in terms of energy consumption, carbon footprint, cost, and environmental impact indicated that the proposed large-scale continuous production prototype is greener compared to other methods. Therefore, this approach holds great potential for industrial applications, paving the way for commercialization and facilitating the development of small storage units to explore the properties of the new storage system. [ABSTRACT FROM AUTHOR]

Nanocomposites consisting of conducting polymers and metal oxide are promising material in electrochemical energy storage. The design of nanostructure is regarded as an efficient strategy to improve electron and ion transfer. However, the construction of nanocomposites usually needs multistep reaction. Herein, a poly(3,4-ethylenedioxythiophene)-encapsulated iron oxide/carbon nanotube nanocomposite (Fe2O3/CNTs@PEDOT) is demonstrated as an efficient anode for aqueous supercapacitors. The Fe2O3/CNTs nanocomposite is firstly constructed by a rapid combustion strategy, which provided electrode a good hydrophilic ability. The PEDOT is further in situ constructed on the surface of Fe2O3/CNTs by an electrochemical polymerization process for enhancing the cycling stability. The Fe2O3/CNTs@PEDOT electrode delivers an enhanced ions transfer and stability during the charge/discharge process. In 1 M Na2SO4, such Fe2O3/CNTs@PEDOT-180 s electrode delivers a specific capacitance of 1014 mF cm−2 at 2 mA cm−2 and retains 89.7% of initial capacitance at 20 mA cm−2 after 3000 cycles, which is superior than that of the Fe2O3/CNTs electrode (79.2%). The asymmetric aqueous supercapacitor consisted of Fe2O3/CNTs@PEDOT and MnO2/CC electrodes with an operating potential of 2.0 V reaches a high areal energy density of 0.207 mWh cm−2 at a power density of 2.0 mW cm−2. [ABSTRACT FROM AUTHOR]

Short carbon fiber reinforced aluminum matrix composites exhibit suitable thermal conductivity and desirable coefficient of thermal expansion for electronic packaging applications. The interfacial bonding characteristics between carbon fibers and aluminum matrix play a crucial role in determining the performance of the composites. In the present study, the surface modification of carbon fibers and optimization of fabrication processing parameters were used to ameliorate the interface bonding and improve the properties of carbon fiber/Al composites. The electroless plating method was employed to deposit a nickel coating on the surface of carbon fibers. Aluminum matrix composites reinforced with 20∼50 vol.% uncoated or nickel-coated carbon fibers were fabricated by vacuum hot pressing technique. The microstructures, interface structures, relative density and thermal conductivity of the composites were systematically investigated. The results indicated that carbon fiber/Al composites with relatively high density of 98.9% and acceptable thermal conductivity of 218.1 W·m−1 K−1, as potential candidates for electronic packaging applications, were successfully fabricated. Through the application of nickel coating, the interfacial thermal resistance was effectively reduced by one order of magnitude derived from the experimental calculations using Maxwell-Garnett effective medium approach as a result of improved interface bonding. [ABSTRACT FROM AUTHOR]

Lipid peroxidation is a major process that determines the quality of various oil samples during their use and storage, in which the primary products are hydroperoxides (HP'S). HP'S are very stable compounds at ambient conditions and are harmful to human health. Therefore, the evaluation of the degree of oil oxidation is an excellent tool for ensuring food safety. The peroxide value (PV) is the main parameter used for quality control in oils. Herein, we propose an alternative electrochemical method to the classical iodometric titration method most widely used for determining the PV. Our approach is based on the electrochemical quantification of hydroperoxides/peroxides in an organic solvent medium (acetonitrile and organic ammonium salt) using a composite electrocatalyst–glassy carbon electrode modified with 2D-nanomaterial graphitic carbon nitride doped with Co3O4. Calibration was made by the method of standard addition using benzoyl peroxide (BPO) as a model peroxide compound, dissolved in chloroform and added to fresh Rivana-branded anti-cellulite oil, used as a model oil sample. Calibration plots showed a linear response and the very good reproducibility of the analytical result (R2 ˃ 0.99). Further, in terms of accuracy, the method showed good results, since the BPO quantitative analysis was close to the theoretical response. In addition, the accuracy of the electrochemical method was compared with that of the standard iodometric titration method for determining the PV of vegetable fats (according to a standard method). Finally, using the electrochemical method, the concentration of peroxides was determined in a real sample—an anti-cellulite oil of the trademark Rivana with an expired shelf life. [ABSTRACT FROM AUTHOR]

Niobium pentoxide (T-Nb2O5) is a promising anode material for dual-ion batteries due to its high lithium capacity and fast ion storage and release mechanism. However, T-Nb2O5 suffers from the disadvantages of poor electrical conductivity and fast cycling capacity decay. Herein, a nitrogen-doped three-dimensional porous carbon (RMF) was prepared for loading niobium pentoxide to construct a composite system with excellent electrochemical performance. The obtained T-Nb2O5/RMF composites have a well-developed pore structure and a high specific surface area of 1568.5 m2 g−1, which could effectively increase the contact area between the material and electrolyte, improving the electrode reaction and lithium-ion transfer diffusion. Nitrogen doping increased surface polarity, creating more active sites and accelerating the electrode reaction rate. The introduction of T-Nb2O5 imparted high power density and excellent cycling stability to the battery. The composites exhibited good electrochemical performance when used as dual-ion battery anode, with a stable cycle life of 207.2 mA h g−1 at 1 A g−1 current density after 650 cycles and great rate performance of 181.5 mA h g−1 at 5A g−1 was also obtained. This work provides the possibility for applying T-Nb2O5/RMF as an anode for a high-performance dual-ion battery. [ABSTRACT FROM AUTHOR]

Mixed-metal nickel-iron, NixFe materials draw attention as affordable earth-abundant electrocatalysts for the oxygen evolution reaction (OER). Here, nickel and mixed-metal nickel-iron metal–organic framework (MOF) composites with the carbon materials ketjenblack (KB) or carbon nanotubes (CNT) were synthesized in situ in a one-pot solvothermal reaction. As a direct comparison to these in situ synthesized composites, the neat MOFs were postsynthetically mixed by grinding with KB or CNT, to generate physical mixture composites. The in situ and postsynthetic MOF/carbon samples were comparatively tested as (pre-)catalysts for the OER, and most of them outperformed the RuO2 benchmark. Depending on the carbon material and metal ratio, the in situ or postsynthetic composites performed better, showing that the method to generate the composite can influence the OER activity. The best material Ni5Fe-CNT was synthesized in situ and achieved an overpotential (η) of 301 mV (RuO2 η = 354 mV), a Tafel slope (b) of 58 mV/dec (RuO2 b = 91 mV/dec), a charge transfer resistance (Rct) of 7 Ω (RuO2 Rct = 39 Ω), and a faradaic efficiency (FE) of 95% (RuO2 FE = 91%). Structural changes in the materials could be seen through a stability test in the alkaline electrolyte, and chronopotentiometry over 12 h showed that the derived electrocatalysts and RuO2 have good stability. [ABSTRACT FROM AUTHOR]

This paper experimentally investigates the impact response of composite laminates made with conventional and bio-based epoxy resin. Drop tower impact tests were conducted at varying energy levels, including repeated low-energy impacts, to evaluate perforation resistance. The laminates' residual strength and damage tolerance were assessed using the Damage Index (DI) and by analysing the resonance frequency variations through the Impulse Excitation Technique (IET). The study demonstrates a strong correlation between the DI and the resonance frequencies of the specimens, suggesting that IET can effectively track damage progression in composite laminates. Bio-based resin laminates exhibited higher energy absorption at perforation and lower damage progression during repeated impacts due to the higher ductility of the resin. This method of using resonance frequencies to assess impact damage progression directly in composite laminates throughout the IET technique has not been previously reported in the literature. [ABSTRACT FROM AUTHOR]

The development of copper-based materials with a high efficiency and low cost is desirable for use in iodine (I2) remediation. Herein, Cu0-nanoparticles-functionalized, ZIF-8 (Zeolite Imidazole Framework-8)-derived, nitrogen-doped carbon composites (Cu@Zn-NC) were synthesized by ball milling and pyrolysis processes. The as-prepared composites were characterized using SEM, BET, XRD, XPS, and FT-IR analyses. The results showed that the morphology of ZIF-8 changed from a leaf-like structure into an irregular structure after the introduction of a copper salt and carbonization. The copper in the pyrolysis samples was mainly in the form of Cu0 particles. The presence of an appropriate amount of Cu0 particles could increase the specific surface area of Cu@Zn-NC. The subsequent batch adsorption results demonstrated that the as-fabricated composites showed high I2 adsorption amounts (1204.9 mg/g) and relatively fast dynamics in an iodine–cyclohexane solution when the Cu content was 30% and the pyrolysis temperature was 600 °C, outperforming the other Cu-based materials. The isothermal adsorption followed both Langmuir and Dubinin–Radushkevich isotherm models, while the kinetics of I2 adsorption followed a pseudo-second-order kinetic model. The activation energy (Eα) of the adsorbent was determined to be 47.2 kJ/mol, according to the Arrhenius equation. According to the experimental and DFT analyses, I2-Zn interactions and I2-Cu0 chemisorption jointly promoted the elimination of iodine. In general, this study provided an operative adsorbent for the highly effective capture of iodine in solution, which might be worth applying on a large scale. [ABSTRACT FROM AUTHOR]

This study investigates carbon fabric-reinforced thermoplastic composites produced via hot pressing, using Polyamide PA6 and Polybutylene Terephthalate (PBT) as matrix materials. These materials are increasingly utilized in the development of lightweight, high-performance, multilayer structures, such as aluminum-reinforced laminates, for automotive and aerospace applications. The mechanical properties, including tensile strength and stiffness, were systematically evaluated under varying loading conditions. The PBT-CF composite exhibited a 17% higher tensile strength and stiffness compared to the PA6-CF composite, despite the low carbon fiber content. This highlights the critical role of uniform fiber distribution in enhancing material performance. Slower loading speeds (1 mm/min) resulted in higher strength, emphasizing the influence of process parameters on mechanical behavior. Cyclic loading tests showed a gradual reduction in stiffness with increasing strain range, particularly for the CF-45° configuration. The warp and weft arrangement of the carbon fabric contributed to structural inhomogeneity but did not significantly affect the global mechanical properties. These findings demonstrate the suitability of PBT as a matrix material alongside PA6 for carbon fiber-reinforced thermoplastics, offering new possibilities for the design of advanced composite materials with tailored properties. [ABSTRACT FROM AUTHOR]

Carbon/ceramic composites with negative permittivity have motivated a considerable concern due to their special properties and various applications. Herein, series of alumina ceramic composites consisting of different carbon fillers were prepared by the hot-pressed sintering, and the carbon fillers included carbon sphere (CS), carbon black (CB), carbon fibre (CF), carbon nanofibre (CNF) and graphene nanosheet (GN). The impact of various carbon fillers on the electrical performance of composites were investigated comparatively. It was found that CF ceramic had hopping conduction, capacitive character and positive permittivity, and micron-sized CFs were embedded in isolation within the ceramic composite. The other ceramics with carbon nanofillers demonstrated metallic-type conductance, inductive character and negative permittivity. The carbon nanofillers evenly dispersed and easily formed carbon network that improve the flow of free electrons in the composites, and the negative permittivity behavior imputed to the low frequency plasmonic state of abundant free electrons in the carbon networks. Furthermore, the magnitude of negative permittivity was in connection with the type of carbon nanofiller. The one- or two-dimensional carbon nanofillers were more easily connected to each other to form a denser carbon network, and thus the CNF and GN ceramics had the larger absolute values of negative permittivity, which was in accord with Drude model. [ABSTRACT FROM AUTHOR]

Laminates are produced by stacking prefabricated plies composed of fiber products. Within the aerospace industry, a ply thickness of 125 μ m is commonly regarded as the standard. Ply thicknesses of less than 100 μ m are generally considered as thin plies. Due to their ability to provide superior mechanical properties relative to conventional laminates thin-ply (TP) laminates are gaining interest in several high-tech industries. Although the research on TP laminates increased over the past few years, a comprehensive evaluation of the mechanical behavior of TP laminates accounting for the ply-thickness is an ongoing challenge due to the intricacies of ply interactions, and experimental difficulties. The mechanical response of fiber reinforced polymer laminates is governed by damage progression during loading, with the thickness of individual plies playing a crucial role in influencing the initiation and evolution of local cracks and failures. Therefore, in this study, the effective mechanical properties of carbon fiber reinforced polymer composite with varied ply thicknesses have been experimentally evaluated and the accumulation of the damage events has been monitored using acoustic emission measurements, utilizing a contactless laser vibrometer. In this experimental study, the ply thickness is increased in a systematic manner (ranging from 50 μ m to 200 μ m). Experimental investigation has been carried out in quasi-static tension and compression. The results show that unnotched TP laminates subjected to tensile loading demonstrate enhanced effective strength, attributed to less premature failure. Conversely, as the thickness of the lamina increases, there is a reduction in the overall strength of the laminate. However, in the case of the notched specimen lowest strength has been observed at a ply-thickness of 100 μ m in this study. Under compressive loading, unnotched and notched specimen tends to show similar mechanical behavior to unnotched specimens under tensile loading. The overall strength is raised with decreasing ply thickness. The findings from this study may be valuable for incorporating ply-thickness considerations into models for predicting the mechanical performance of laminates under dynamic loading. [ABSTRACT FROM AUTHOR]

[Display omitted] • Confinement of cross-linked ionic polymer within the pores of porous carbon. • Ionic liquid@porous carbon composites with accessible active sites. • Exceptional catalytic conversion across various epoxides. • Confinement effect enhancing stability and activity. • Novel insights for functionalized porous carbon catalyst design. It is crucial to employ an integrated catalyst to avoid the complications of the recovery process. This work reports the fabrication of porous carbon@ionic liquid (PC@IL) composites with readily accessible active ion sites, achieved by confining cross-linked ionic liquid (IL) within the channels of porous carbon (PC). The incorporation of porous carbon not only confines the IL within its framework, creating microsites for CO 2 adsorption and conversion, but also simplifies catalyst recovery. The results indicate that PC@IL composites exhibit excellent cycloaddition activity towards CO 2 in a co-catalyst- and solvent-free environment. Notably, PC@IL(C)-24 demonstrates remarkable catalytic performance across various epoxides under 1 bar of CO 2 , with yields above 90 % at 90 °C for 12 h, and achieving a remarkable styrene carbonate yield of up to 92.8 % under a CO 2 pressure of 1 bar (at 100 °C for 12 h). Control experiments confirm that the confinement effect exerted by N,S co-doped carbon on cross-linked IL plays a pivotal role in enhancing both stability and activity of PC@IL composites, thereby providing novel insights for designing functionalized porous carbon catalysts for CO 2 cycloaddition conversion. [ABSTRACT FROM AUTHOR]

The development of high-performance energy storage devices is essential for advancing sustainable technologies. This study explores the potential of a novel composite material composed of high entropy alloys (HEAs) and green carbon for supercapacitor applications. High entropy alloys, characterized by their unique multi-principal element compositions, offer exceptional electrochemical stability and electrical conductivity. When combined with green carbon derived from biomass, the composite exhibits synergistic effects, including enhanced capacitance, high energy density, and improved cycling stability. Accordingly, the synthesis of rice straw green carbon and its composites with high entropy alloys refers to a novel material for high-specific capacitance supercapacitor applications. The green carbon composite electrode along with Fe–Co–Ni–Cr–Mn (FCNCM) high entropy alloy powder exhibits a significantly improved specific capacitance value of 450 F g−1 at 2 A g−1 as compared to pure HEA and biochar electrode in a three-electrode system with a wide potential window of 1.3 V. These outstanding three electrode characteristics enabled the development of a symmetric liquid state device with a 3 M KOH aqueous electrolyte operated up to 1.8 V and displays a specific energy of 33.5 W h kg−1 by consuming specific power of 1800 W kg−1. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA) is a typical environmental estrogen that is distributed worldwide and has the potential to pose a hazard to the ecological environment and human health. The development of an efficient and sensitive sensing strategy for the monitoring of BPA residues is of paramount importance. A novel electrochemical sensor based on carbon black and carbon nanofibers composite (CB/f-CNF)-assisted signal amplification has been successfully constructed for the amperometric detection of BPA in foods. Herein, the hybrid CB/f-CNF was prepared using a simple one-step ultrasonication method, and exhibited good electron transfer capability and excellent catalytic properties, which can be attributed to the large surface area of carbon black and the strong enhancement of the conductivity and porosity of carbon nanofibers, which promote a faster electron transfer process on the electrode surface. Under the optimized conditions, the proposed CB/f-CNF/GCE sensor exhibited a wide linear response range (0.4–50.0 × 10−6 mol/L) with a low limit of detection of 5.9 × 10−8 mol/L for BPA quantification. Recovery tests were conducted on canned peaches and boxed milk, yielding satisfactory recoveries of 86.0–102.6%. Furthermore, the developed method was employed for the rapid and sensitive detection of BPA in canned meat and packaged milk, demonstrating comparable accuracy to the HPLC method. This work presents an efficient signal amplification strategy through the utilization of carbon/carbon nanocomposite sensitization technology. [ABSTRACT FROM AUTHOR]

The highly toxic substances contained in spent cathode carbon blocks (SCCB) pose a serious threat to human health and the ecological environment, and are difficult to recycle. To address this issue, we utilize H2O2 to oxidize cyanides and grow hydroxyapatite (HAP) on spent cathode carbon blocks to adsorb fluoride ions, achieving controlled removal of cyanides and fluorides. Subsequently, the hydroxyapatite‐spent cathode carbon block composite material (H‐SCCB) is applied to modified asphalt, and simulations of the interaction between hydroxyapatite interfaces and asphalt components are conducted. The results indicate that the total cyanide and fluoride ion concentrations in the experimental wastewater meet the discharge standards for industrial wastewater in China. Hydroxyapatite successfully grows on SCCB, presenting a rich porous structure and significantly increased surface area. Mechanical testing shows that 4% H‐SCCB exhibits optimal performance, with a 23.28% increase in complex modulus (G*) compared to the matrix asphalt. Creep recovery capability (R) increases by 54.32% and 7%, respectively. Additionally, molecular dynamics simulations reveal that the interface adsorption between hydroxyapatite and asphalt binder is primarily influenced by electrostatic forces. Under the influence of hydroxyapatite, the diffusion abilities of asphalt four components are as follows: resin > aromatic > saturate > asphaltene. [ABSTRACT FROM AUTHOR]

Process-induced microstructure modification was investigated for the strengthening mechanism of laser powder bed fusion fabricated (LPBF) Ti-6Al-4 V material. An innovative approach by mimicking the fiber structure of the composite materials was studied. Different cylindrical reinforcement diameters were selected in the LPBF-fabricated Ti-6Al-4 V samples to replicate the function of the carbon fibers in composite materials, providing stiffness and reinforcement in the matrix. The corresponding regions of the assigned reinforcement shape at each layer were exposed to a secondary laser scan through the sample during the fabrication. Multi-scan laser scanning strategies, involving a combination of laser power and scan speed, were employed after the melting laser scan to maximize the relative density of the material. The optimized post-heating laser scan enhanced the relative density (> 99.95%), recrystallized the α and α′ phases' lath morphology, modified the lattice structure, transformed the initial microstrain mode, and enhanced the inherent grain texture of the PBF fabricated Ti-6Al-4 V. The tailored microstructure achieved a 46.5% higher yield strength (YS) accompanied by a 99.3% higher elongation. [ABSTRACT FROM AUTHOR]

It is more and more difficult to identify defects in carbon fiber composite materials due to the difficulty in making defect samples and the single signal analysis method. In order to better solve the problem of defect identification in carbon fiber composite materials, this study uses ultrasonic phased array equipment to quantitatively locate and detect carbon fiber composite laminates with embedded delamination defects, so as to more intuitively and effectively display the appearance of different delamination defects. The time domain analysis of the collected ultrasonic original signal and the time‐frequency domain analysis using wavelet packet are carried out. A total of 6 eigenvalues were extracted to reflect the ultrasonic signals of different delamination defects. By using genetic algorithm to optimize BP neural network, the recognition accuracy of delamination defects of different sizes is more than 95%, and the recognition accuracy of delamination defects of different depths is 100%, so as to realize the effective intelligent recognition of delamination defects of different sizes and depths of carbon fiber composites. This study is of great significance to improve the accuracy and reliability of defect identification of carbon fiber composite materials. Highlights: The ultrasonic phased array equipment is used to quantitatively locate the carbon fiber composite laminates with embedded delamination defects, so that the appearance of different defects can be displayed more intuitively and effectively.Using time domain analysis and time‐frequency domain analysis based on wavelet packet, the combination of the two can more comprehensively extract the effective features of the defect signal.The BP neural network is optimized by genetic algorithm, and the results can effectively and automatically identify different layered defects, which lays a good foundation for the rapid and accurate identification of more defects in the future. [ABSTRACT FROM AUTHOR]

In the present study, a discrete layer model was established to explore the vibration performance of Functionally Graded Carbon Nanotube‐Reinforced Composite (FG‐CNTRC) open cylindrical shells with damping film embedded based on the first‐order shell theory. There are four configurations of stacking arrangements considered for FG‐CNTRC open cylindrical shells with damping film embedded. The equivalent structural parameters of the top and bottom FG‐CNTRC panels are generated by implementing the extended mixing rule. Governing equations are derived based on the Hamilton principle and solved with the Naiver solution. Subsequently, after verifying the validity of this paper's solution by comparing it with the published literature, a parametric elaborated investigation discloses the variation patterns of vibration performance of four FG‐CNTRC open cylindrical shells with damping film embedded. The conclusions of the study can be used as a useful guide about open cylindrical composite shell structures with the design of high strength and damping. Highlights: Discrete layer vibration model was bulit based on first‐order shell theory.Vbration performance of FG‐CNTRC open sandwich shells was studied.Variation patterns of frequency and loss factor was disclosed. [ABSTRACT FROM AUTHOR]

This study introduces a multi‐component composite as a substitute for lead grids in ultra‐battery structures. The presented composite decreases the weight and simultaneously extends the cycle life of the traditional lead‐acid battery. Overall, UBZCP (the sample containing metal oxides and polyaniline), as the best sample, increases the cyclic stability by 3.3 and 1.4 times under high rate partial state of charge (HRPSoC) mode, compared to Native and UB450 samples. Metal oxides predominantly enhance the electrical conductivity of carbon‐based composites due to catalytic effects in the reduction of graphene oxide during heat treatment. Poly aniline shows considerably positive effect of electrochemical performance due to the high pseudo‐capacitive properties, high interaction of lead ions and the nitrogen in the polymer chains and accordingly hydrogen evolution reaction (HER) inhibition. The synergistic effect of polyaniline and metal oxides makes the best performance in the UBZCP sample achieve. Also, the UBZCP sample represented an enhancement of about 1.21 and 1.39 times in battery life and specific capacity under deep discharge mode compared to the Native sample. As a result, the introduced multi‐component composite making a 3D conductive network, facilitates Pb/PbSO4 reaction reversibility, and reduces the lead sulfate crystal size. [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li–S) batteries are recognized as an encouraging alternative for future power storage technologies. However, their practical application is hindered by several significant challenges, including slow redox kinetics, the shuttle effect, and the formation of lithium dendrites. Here a binder-free, self-supporting multifunctional interlayer composed of lithium lanthanum titanate (LLTO) with amorphous carbon nanofiber matrices for Li–S batteries has been constructed. This multifunctional interlayer has been designed to facilitate the redox kinetics of lithium polysulfides (LiPSs), promote the nucleation of lithium sulfide (Li2S), and hinder the formation of lithium dendrites. The electrocatalytic properties of the interlayer were subjected to systematic evaluation through electrochemical testing, and the lithium deposition was assessed by examining the surface evolution of lithium metal in symmetric cells. The LLTO carbon matrix interlayer sustained a high specific capacity of 703.3 mA h g−1 after 200 cycles at 0.1C, with a sulfur loading of 5.5 mg cm−2. Furthermore, it demonstrated a high capacity of 905.9 mA h g−1 with a decay rate of 0.069% per cycle over 1000 cycles at a current density of 5C with a sulfur loading of 1 mg cm−2. This investigation highlights the potential of LLTO carbon composite materials as multifunctional interlayers, which could facilitate the optimization of advanced Li–S batteries. [ABSTRACT FROM AUTHOR]

This article provides an overview of the photoelectrochemistry of nano-catalysts, their advantages, mechanisms, and the interactions between nanostructures and reactivity. The applications of nanomaterials in various processes, such as dye degradation, toxicity elimination, HER, CO2RR, and OER were found paramount. The types of catalysis, including homogeneous, heterogeneous, enzymatic, photocatalysis, and photo electrocatalysis, elucidate their significance, and unique applications are also included. Advanced catalysts, from semiconductor nanomaterials to cocatalysts and surface modifications, are explored for their ability to harness light energy and drive efficient redox reactions. The emerging trends in electrocatalyst design, such as metal-free carbon catalysts, carbon nanotubes, graphene, nanodiamond, porous carbon, metal and carbon composite catalysts, and other metal and carbon composite catalysts are very important for future perspectives, therefore their consideration in this review has been focused. It also briefly discusses the advantages and disadvantages of nano-catalysts, including advanced catalysis, photogenerated charge carriers, redox reactions, and cocatalysts and surface modifications. [ABSTRACT FROM AUTHOR]

Highlights The dispersion and interfacial compatibility of carbon nanotubes, as inorganic nonpolar materials, within the organic polar polyamide matrix are crucial for the performance of composite materials. This article reviews the surface modification of carbon nanotubes, common methods for fabricating carbon nanotube/polyamide composites, and their impact on composites properties. Additionally, it discusses the challenges and opportunities in the field of carbon nanotube/polyamide research. CNTs' van der Waals forces and aspect ratio cause agglomeration, hindering dispersion. Inorganic CNTs' nonpolar nature weakens affinity and interfacial bonding with polar PA. Nonpolar CNTs reduce affinity and weaken bonding with polar PA. The interface enables PA‐CNT interaction, crucial for load transfer in composites. Surface‐modified CNTs introduce functional groups, enhancing interfacial bonding with PA. [ABSTRACT FROM AUTHOR]

Highlights Zeolitic imidazolate framework‐8 (ZIF‐8) was used to enhance the interfacial strength of composites due to its large specific surface area, uniform pore size, and high stability. Morphology‐controllable ZIF‐8 nanocrystals were synthesized by solvent method and a layer of small‐sized and height crystalline ZIF‐8 was deposited on carbon fibers via an efficient electrophoretic deposition (EPD) way. The results showed that interlaminar shear strength (ILSS) and tensile strength (TS) of carbon fibers/epoxy composites and the TS of carbon fiber were enhanced by 43.56% and 25.48%, respectively. The strong interfacial adhesion strength between carbon fibers and epoxy was attributed to improving the wettability, ionic interaction and the mechanical interlocking effect induced by porous ZIF‐8, which led to effective energy absorption and load transfer. This highly efficient and controllable method is believed to improve the mechanical properties of carbon fiber composites for a wide range of industrial uses. ZIF‐8s in different sizes and morphology were synthesized by solvent method. MOF was deposited firstly onto carbon fibers though electrophoretic deposition. Materials Studio was used to evaluate the strong anchoring strength. ILSS of composites was enhanced by 43.56%. [ABSTRACT FROM AUTHOR]

Numerous studies have investigated polymeric composites fabricated using fused deposition modelling. However, the mechanical performance of these composites, which is influenced by various factors, including materials and printing parameters, remains unknown. Further understanding these factors helps improve the accuracy of mechanical performance predictions. Therefore, this study fabricates in-house polyamide reinforced with carbon fibre at a composition of 20 wt.% and controls its printing parameters, including layer height and printing orientations. Results indicated that controlling the orientation at a 0° angle are the most crucial factor compared to layer height, which leads to a maximum flexural strength of ∼21 MPa due to improvements in load-bearing capacity and adhesion bonding between the fibre and matrix. [ABSTRACT FROM AUTHOR]

New epoxy (EP)‐based sandwich composites have enhanced mechanical performance and optimized cost‐effectiveness, as a result of composites' increasing popularity. This study aims to develop composites with 3, 5, and 7 layers of woven carbon fibers (WCFs) layered on 3D rayon‐based graphite felt (3D RGF) as the core of the sandwich composites. Using WCFs as face sheet layers increases flexural strength and modulus. Flexural strength increases to 226.92 MPa, and modulus increases to 15.18 GPa with 3 WCFs layers. Five layers increase modulus to 25.43 GPa and flexural strength to 370.21 MPa. Seven layers provide the highest modulus of 31.38 GPa and flexural strength of 405.07 MPa. Diverse concentrations of nanosilica (0.01, 0.1, 0.5, and 0.8 wt%) were embedded within the core to bolster its mechanical properties. Using an in situ casting method, an EP resin solution was infused into the structure, forming a bicontinuous composite. This method significantly enhances the toughness and adhesion between the fibers and the EP resin, resulting in superior mechanical properties. EP alone has 57‐MPa tensile strength, but three layers of WCFs increase it to 531.38 MPa, five layers increase it to 647.24 MPa, and seven layers increase it to 764.40 MPa. The minimum tensile modulus of EP is 2.75 ± 0.5 GPa. The modulus increases significantly when layers of WCFs are added, reaching 9.75 GPa with three layers, 14.96 GPa with five layers, and a maximum value of 23.44 GPa with seven layers. When a little amount of nanosilica was added, the flexural properties of composites were significantly affected. Among all concentrations, 0. 5 wt% nano‐SiO2 yielded the highest enhancement of flexural strength and modulus. At 0.1 wt% nanosilica, the flexural strength and modulus of the sandwich composites increase to 493.5 MPa and 30.5 GPa (23.4% and 24.5%). The peak occurs at 0.5 wt%, reaching 645.7 MPa and 41.5 GPa (61.4% and 69.4%). However, at 0.8 wt%, values drop to 560.1 MPa and 30.4 GPa, still showing 40.0% and 24.1% improvements. This study provides a new solution for reinforcing the mechanical properties of EP sandwich composites. Increasing the performance with nanofiller concentrations is also emphasized. [ABSTRACT FROM AUTHOR]

Electrodialysis (ED) and electrodeionization (EDI) are the new methods that are being used in water desalination processes. Reliable, electrochemically stable and efficient electrodes are the crucial components of the ED/EDI electrodialysers. The article proposes a new material for electrodes in electromembrane desalination systems. Graphene composite electrodes were created by bonding carbon fibres with epoxy resin and then coated with a layer of nanostructured, reduced graphene oxide. The graphene electrode material underwent electrochemical characterization by cyclic voltammetry, electrochemical impedance spectroscopy and potentiostatic polarization techniques. FTIR and Raman spectroscopy were used to determine the material's chemical structure. The change in the surface morphology and elemental composition of the electrodes after fabrication and exploitation of the composite was studied by SEM and EDS. The electrodes were used successfully in multi-electrode electrodialysis devices, resulting in a desalination rate of over 90%. The electrodes were proven to be functional and durable. It was also confirmed that the oxidation/reduction phenomena on the electrode surfaces were fully reversible after changing their polarization, which was used cyclically to clean the electrodialyser. The parameters obtained indicate that this material can also be successfully used in other electrode processes. [ABSTRACT FROM AUTHOR]

CuS microflowers composites with Vulcan carbon black (CuS/Vulcan) were synthesized by a low-cost one-pot hydrothermal process and investigated as electrode materials for supercapacitor applications. The phase integrity of pristine CuS and CuS/Vulcan composites was confirmed by XRD measurements. The immobilization of CuS nanoparticles on the Vulcan support prevented their agglomeration and improved the specific surface area, the electric conductivity and the electrochemical response time of CuS-based electrodes. The electrochemical performance of CuS/Vulcan composites was characterized in a three-electrode setup and a two-electrode cell configuration as a function of the CuS/Vulcan weight ratio. The CuS/Vulcan composite electrodes with a mass ratio of 70:30 demonstrated the highest specific capacitance of 285 F g−1 and a capacitance retention of 97% after 2000 galvanostatic charge–discharge cycles at 5 A g−1 in 3M KOH. The assembled CuS/Vulcan (70:30)//CuS/Vulcan (70:30) symmetric cell exhibited an improved specific energy of 12.6 Wh kg−1 at a specific power of 907 W kg−1 (at the discharge current density of 0.25 A g−1). Overall, this study presented a facile, convenient and scalable approach for designing cost-effective and high-performance composite electrodes based on copper sulfide. [ABSTRACT FROM AUTHOR]

Composite materials play a crucial role in various industries, including aerospace, automotive, and shipbuilding. These materials differ from traditional metals due to their high specific strength and low weight, which reduce energy consumption in these industries. The damage behavior of such materials, especially when subjected to stress discontinuities such as central holes, differs significantly from materials without holes. This study examines this difference and predicts the damage behavior of carbon fiber composites with multiple holes using a progressive damage model through finite element analysis (FEM). Two holes were positioned along the central axis of symmetry in the longitudinal and transverse directions relative to the load. The presence of additional holes acts as a stress-relief factor, reducing stress by up to 17% when the holes are arranged in the longitudinal direction. A cohesive zone model with two parameters, including constant and linear shapes, was applied to develop a simple analytical model for calculating the nominal strength of multi-hole composite laminates, based on the unnotched plate properties of the material. The results closely match experimental findings. The data also provide design tables that can assist with material selection. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) have garnered significant interest in the field of nanotechnology owing to their unique structure and exceptional properties. These materials find applications across a diverse array of fields, including electronics, environmental science, energy, and biotechnology. CNTs serve as potent reinforcing agents in polymer composites; even minimal additions can significantly improve the mechanical, electrical, and thermal properties of polymers. With the growing demand for polymer composites across various industries, there is an anticipation for CNT/polymer composites to evolve in increasingly diverse directions. This paper reviews recent advancements in the manufacturing techniques of various CNT/polymer composites and discusses the enhancements in their mechanical, electrical, and thermal properties. Furthermore, it explores the potential applications of these composites. [ABSTRACT FROM AUTHOR]

Carbon-fiber-reinforced composites of ultra-high-molecular-weight polyethylene (UHMWPE) are not easily prepared because of their high viscosity, although they can be advantageous in advanced engineering applications due to their superior mechanical properties in combination with their low specific weight and versatility. Short polyacrylonitrile-based carbon-fiber-reinforced UHMWPE composites with fiber contents of 5, 10, and 15 wt.% could easily be prepared using in situ ethylene polymerization. Therefore, MgCl2 was generated at the Brønsted acidic groups of the fiber surface by employing a reaction between the co-catalysts Mg(C4H9)2 and AlEt2Cl. Titanation with TiCl4 resulted in a catalyst directly on the fiber surface. The catalyst polymerized ethylene (2 bar pressure at 50 °C), forming a UHMWPE matrix near the surface; its fragmentation led to polymer particles associated with the fiber. The catalyst activity on the fiber surface of untreated (CF-Pr, 3.48 ± 0.24 wt.%) and oxidized fibers (CF-Ox, 7.41 ± 0.03 wt.%) was 20% lower. CF-Pr compression-molded samples showed tensile strengths of up to 50.4 ± 1.3 MPa, while CF-Ox samples reached 39.1 ± 0.6 MPa, surpassing the performance of composites prepared by melt compounding. The stiffness of 1.58 ± 0.17 GPa for a melt-compounded material was lower than the 3.24 ± 0.10 GPa for CF-Pr and 2.19 ± 0.07 GPa for CF-Ox composites. A fracture examination showed fiber pull-outs, matrix residues on the fibers, and the formation of some extensional polymer fibrils. The latter explains the higher stress at yield and the breakage of the CF-Pr based composites in particular. The potential of in situ polymerized UHMWPE composites for the utilization in high-performance structural applications is thus demonstrated. [ABSTRACT FROM AUTHOR]

Cleavable bio-based epoxy resin systems are emerging, eco-friendly, and promising alternatives to the common thermoset ones, providing quite comparable thermo-mechanical properties while enabling a circular and green end-of-life scenario of the composite materials. In addition to being designed to incorporate a bio-based resin greener than the conventional fully fossil-based epoxies, these formulations involve cleaving hardeners that enable, under mild thermo-chemical conditions, the total recycling of the composite material through the recovery of the fiber and matrix as a thermoplastic. This research addressed the characterization, processability, and recyclability of a new commercial cleavable bio-resin formulation (designed by the R-Concept company) that can be used in the fabrication of fully recyclable polymer composites. The resin was first studied to investigate the influence of the different post-curing regimes (room temperature, 100 °C, and 140 °C) on its thermal stability and glass transition temperature. According to the results obtained, the non-post-cured resin displayed the highest Tg (i.e., 76.6 °C). The same post-curing treatments were also probed on the composite laminates (glass and carbon) produced via a lab-scale vacuum-assisted resin transfer molding system, evaluating flexural behavior, microstructure, and dynamic-mechanical characteristics. The post-curing at 100 °C would enhance the crosslinking of polymer chains, improving the mechanical strength of composites. With respect to the non-post-cured laminates, the flexural strength improved by 3% and 12% in carbon and glass-based composites, respectively. The post-curing at 140 °C was instead detrimental to the mechanical performance. Finally, on the laminates produced, a chemical recycling procedure was implemented, demonstrating the feasibility of recovering both thermoplastic-based resin and fibers. [ABSTRACT FROM AUTHOR]

Fiber hybridization can effectively solve the localized brittle fracture problem of composite honeycomb, but the interaction between different fibers leads to a very complex failure mechanism. Hence, 3D-printed hybrid continuous fiber composite honeycombs with a combination of carbon and Kevlar fibers are designed to study the structural failure behaviors by the experiment and simulation method. The experimental samples, including Onyx, carbon, Kevlar, carbon/Kevlar, and Kevlar/carbon composites, are fabricated based on Markforged 3D printing technology, and the crushing tests are conducted to evaluate the failure behaviors. An equivalence finite element modeling method to replace the heterogeneous microstructure of hybrid composites is proposed to analyze the failure behaviors. Results indicate that carbon/Kevlar honeycomb exhibits the highest energy absorption and cost effectiveness, while CFRP honeycomb demonstrates the highest load-carrying capacity. It is found that carbon/Kevlar and Kevlar/carbon honeycombs have significant hybrid effects compared to single-fiber honeycombs, which also reveals the hybrid mechanisms between carbon and Kevlar fibers. Furthermore, the Onyx honeycomb, lacking long fibers, exhibits brittle collapse, whereas other honeycombs show ductile collapse due to the presence of Kevlar fibers. Combining the simulation studies, the damage evolution mechanisms of honeycombs, including fiber/matrix tension and compression, shear damage, interface damage, etc., are further revealed. This work provides valuable insights into the design and failure analysis of 3D-printed hybrid fiber composite honeycombs. [ABSTRACT FROM AUTHOR]

Pultruded carbon fiber-reinforced composites are attractive to the wind energy industry due to the rapid production of highly aligned unidirectional composites with enhanced fiber volume fractions and increased specific strength and stiffness. However, high volume carbon fiber manufacturing remains cost-prohibitive. This study investigates the feasibility of a pultruded low-cost textile carbon fiber-reinforced epoxy composite as a promising material in spar cap production was undertaken based on mechanical response to four-point flexure loading. As spar caps are primarily subjected to flexural loading, large-span four-point flexure was considered, and coupon testing was restricted to tensile modulus and compression strength assessment. High-resolution spatial fiber optic strain sensing was utilized to determine spatial strain distribution during four-point flexure, revealing consistent strain along the length of the part and proved to be an excellent option for process manufacturing quality examination. Additionally, holes with diameters of 2.49 mm, 5.08 mm, and 1.93 mm were drilled through the thickness of full-width parts to determine the feasibility of structural health monitoring of pultruding parts internal to wind blades via fiber optic strain sensing. [ABSTRACT FROM AUTHOR]