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We report on the studies of conduction mechanism, direct current conductance, and 1 f -noise of cellulose nanofiber (CNF) and multiwalled carbon nanotube (MWCNT) composites. The composites were characterized by x-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy. The temperature- and voltage-dependence of the dc conductance Σ were, respectively, probed to investigate the charge transport mechanism and the electrical response of the composite. At room temperature, the increase in Σ with wt. % of MWCNT ϕ showed typical percolation behavior. The Σ − T behavior was fitted to the combination of one-dimensional variable range hopping and the fluctuation-induced tunneling, which were attributed to hopping of charge carriers through 1D MWCNTs and the tunneling of charge carriers between the bundles of MWCNTs, respectively. The non-Ohmic electrical conduction was characterized by the onset voltage V 0 (T) which scaled with Ohmic conductance Σ 0 as V 0 (T) ∼ Σ 0 (T) x T , with x T being the onset exponent increased with ϕ. A scaling description based on the data collapse method was adopted to find the parameters V 0 (T) and x T. The noise power spectrum S V (f) followed the relation S V (f) ∼ V β with two different power-laws: β 1 in the Ohmic and β 2 in the non-Ohmic region (β 1 > --> β 2). Interestingly, this change in power-laws occurs at the same V 0 (T) obtained from Σ − V curves. A simple model was proposed to explain the noise behavior after V 0 (T). It is expected that such electrical characterization of CNF-MWCNT nanopaper composite would open up their possibility of application in flexible electronic devices, intelligent networks, sensors, and actuators. [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced composite materials are often used to protect spacecraft from hypervelocity impacts with micrometeoroids or space debris. Therefore, shock-wave properties of these materials at pressures corresponding to orbital impact velocities are of interest. Experimental studies of shock compressibility of unidirectional carbon fiber polymer composite with longitudinal and transverse fiber orientation relative to the direction of shock-wave propagation have been carried out in the pressure range of up to 200 GPa. Particle velocity profiles on the composite surface-water window interface were recorded with a multichannel laser interferometer. The formation of a two-wave structure with a precursor amplitude from 1.5 to 3 GPa was observed with longitudinally oriented fibers. We show that Hugoniot of the composite material almost does not depend on the orientation of the carbon fibers, except for low pressures, when the particle velocity does not exceed 1 km/s. The graphite/diamond phase transition and the destruction of epoxy resin result in a characteristic kink on the Hugoniot curve with a distinct two-phase state region in the 23–35 GPa pressure range. [ABSTRACT FROM AUTHOR]

Cantilever-free scanning probe microscopy has enormous potential for high-throughput topography imaging using parallel probe arrays. However, the current imaging mechanism of the cantilever-free tip architecture hardly considers the efficiency of the detection method regarding precision and bandwidth, which could be a bottleneck to expanding the application of this measurement system. In this communication, we present a contact resistance-based cantilever-free imaging system using radio frequency (RF) reflectometry. RF reflectometry measurements provide sensitive detection of the contact resistance with a wide bandwidth, enabling sub-micrometer-scale topography imaging. We demonstrated our imaging system using a carbon black-polydimethylsiloxane composite tip with a custom-built RF reflectometry setup. The proof-of-concept system achieved a resolution of 230 nm and a bandwidth of the detection system of approximately 8.5 MHz, validating the feasibility of the imaging technique for potential high-throughput cantilever-free scanning probe microscopy. [ABSTRACT FROM AUTHOR]

[Display omitted] Deleterious volumetric expansion and poor electrical conductivity seriously hinder the application of Si-based anode materials in lithium-ion batteries (LIBs). Herein, boron-doped three-dimensional (3D) porous carbon framework/carbon shell encapsulated silicon (B-3DCF/Si@C) hybrid composites are successfully prepared by two coating and thermal treatment processes. The presence of 3D porous carbon skeleton and carbon shell effectively improves the mechanical properties of the B-3DCF/Si@C electrode during the cycling process, ensures the stability of the electrical contacts of the silicon particles and stabilizes the solid electrolyte interface (SEI) layer, thus enhancing the electronic conductivity and ion migration efficiency of the anode. The developed B-3DCF/Si@C anode has a high reversible capacity, excellent cycling stability and outstanding rate performance. A reversible capacity of 1288.5 mAh/g is maintained after 600 cycles at a current density of 400 mA g−1. The improved electrochemical performance is demonstrated in a full cell using a LiFePO 4 -based cathode. This study presents a novel approach that not only mitigates the large volume expansion effects in LIB anode materials, but also provides a reference model for the preparation of porous composites with various functionalities. [ABSTRACT FROM AUTHOR]

In this work, pristine calcium titanate (CaTiO3), polyaniline (PANI), binary PANI@carbon black (CB), and ternary PANI@CB/CaTiO3 composites were synthesized using solid-state and in situ oxidative polymerization method. XRD, FTIR, UV–Vis, PL, FE-SEM, and EDX analyses were studied in order to examine the structural, optical, and morphological properties of all grown samples. XRD, FTIR, FESEM, and EDX findings confirmed the formation of successful chemical organization among PANI, CaTiO3, and CB. The UV–Vis and PL investigation reaffirmed the reduction in optical band gap (2.67 eV–2.56 eV) and charge carrier recombination process due to inclusion of CaTiO3 into CB-reinforced polymer matrix. In photocatalytic experiment, PANI@CB/10%CaTiO3 catalyst showed efficacious performance to degrade the synthetic dyes (99.7% MO and 97.8% MB) after 120-min sunlight irradiation with higher rate and superb stability up-to 5th cycle against MO dye. In kinetic examination, pseudo-first-order kinetic model was obeyed by both dyes. Herein, the bulk heterojunction (BHJ) photovoltaic cell was fabricated by spin-coating the grown samples on FTO glass substrate and thermally evaporating the Al electrode subsequently. The BHJ fabricated by PANI@CB/10%CaTiO3 showed better efficiency (0.541%), photocurrent density (Jsc) (4.21 mA/cm2), and open-circuit voltage (Voc) (0.39 V). [ABSTRACT FROM AUTHOR]

A new Si 3 N 4 coating was proposed and prepared as bonding layer for improving the high temperature thermal shock resistance of carbon/carbon composites (C/C). It is found that the mass loss of the AO20/Si 3 N 4 coating was 0.60% after oxidation at 1723 K for 69 h in air, and 2.86% after oxidation at 1673 K for 134 h. In particular, the coating sample has excellent thermal shock resistance, where the mass loss of the sample is only 0.03% after 33 times of thermal shock from 1673 K to room temperature. The excellent oxidation and thermal shock resistance are mainly attributed to the better thermal expansion mismatch of the coatings, self-healing ability of the glass layer, and the formation of Si 2 N 2 O, which expected to enhance the potential application of C/C in more severe thermal shock environment. [ABSTRACT FROM AUTHOR]

A single-layer and double-layer corrugated core sandwich structure consisting of carbon fibre–reinforced polymer (CFRP) panels and aluminium alloy core layers was designed. Numerical simulations were carried out in HyperMesh/LsDyna, and the simulation results of single-layer and double-layer corrugated sandwich structure were compared with the experimental results to verify the reliability of the proposed numerical model. Compared with the results of single-layer and double-layer corrugated sandwich structure, the superiority of a double-layer corrugated sandwich structure in anti-collision performance is verified. Considering the effects of impact energy and impact position on impact force, energy absorption capacity, and failure mode, a series of low-velocity impact finite element simulations was carried out. It was found that the main failure mode of composite laminates included fibre damage, matrix damage and delamination, and core buckling. At the same impact position, the higher the impact energy, the greater the initial slopes of the contact force-time and absorbed energy-time curves, the higher the peak force, and the larger the energy absorption capacity. Under the same impact energy, when the impactor hit the wave crest of the sandwich structure, the damage to the structure was small; however, the maximum impact force on the structure was large (∼8 kN). [ABSTRACT FROM AUTHOR]

Flexible piezoelectric devices have attracted much attention in the fields of intelligent devices and biomedicine because of their high sensitivity, stability, and flexibility. In this paper, a multifunctional flexible pressure sensor was prepared by adding polyacrylonitrile (PAN) and carboxylic-terminated multi-walled carbon nanotubes (c-MWCNTs) with polyvinylidene difluoride (PVDF) as the substrate. The β -phase content of PVDF/PAN blended fibers compounded with c-MWCNT was up to 95%. At the same time, when PAN was added, the mechanical properties of the composite fibers were constantly improved. The results show that the polymer blending method can improve the comprehensive properties of PVDF composite. The flexible sensor prepared from the PVDF/PAN/c-MWCNT composite film has an output voltage of 2.1 V and a current of 7 μ A. The addition of c-MWCNT can largely improve the sensitivity of the sensor (4.19 V N−1). The sensor is attached to the finger and shows good output performance under different degrees of bending of the finger. The maximum output voltage of the sensor is 0.4 V, 0.56 V and 1.15 V when the finger bending angle is 30°, 60°, and 90°, respectively. Moreover, the developed piezoelectric sensor can monitor large-scale movements of various parts of the human body. Therefore, this composite material shows potential in areas such as motion monitoring and energy storage devices. [ABSTRACT FROM AUTHOR]

Carbon/carbon composites were prepared by densifying a three-dimensional preform made of mesophase pitch-based carbon fiber woven fabric lamination and PAN-based carbon fiber z-pin. Afterwards, SiC coating was prepared on them by pack cementation, and their ablation performances were investigated. Results show that the stacked of pitch-based carbon fiber woven fabrics in Z direction induces a high thermal conductivity of composites in in-plane direction and a sawtooth-structured surface of SiC coating, which helps to decrease the surface temperature (from 1778 to 1614 ℃) and the thermal stress of coating during ablation. Thus, a greatly improved ablation resistance is obtained for the coating in the X-Z plane, showing a mass ablation rate of − 0.01 mg/s and a linear ablation rate of − 0.12 µm/s, respectively, 90.9% and 105.2% lower than that of the X-Y plane. Our findings can provide a meaningful way for the development of high-performance ablation-resistant C/C composites. [ABSTRACT FROM AUTHOR]

In this study, the mechanical behavior of Single Lap Joints (SLJ) subjected to tensile loading was investigated both experimentally and numerically by considering different SLJ sizes including adherend thickness (T:0.88, 1.76, 3.52 mm), joint width (W:10, 20, 30 mm), and overlap length (L:10, 20 mm). A polyurethane adhesive and carbon fiber composite adherends were used for the experimental activity. The experimental campaign was carried out to assess the effects of the SLJ geometry on the mechanical behavior of SLJ. Further, SLJ tests were used to estimate the fracture toughness in mode I and II by using Finite Element methods (FEM) coupled with optimization analysis. The results showed that all three parameters strongly change the load capacity of the joints. According to the Experiments, for every sample configuration, the higher the adherend thickness the higher the adhesive shear and the lower the substrate normal stresses. Moreover, the width showed negligible effect on adhesive shear and substrate normal stresses. Numerically, the effect of geometric parameters has been analyzed once at relative 25% of ultimate load and once at a fixed load for each sample. At 25% of ultimate load, it was observed that the increase in the joint width has nearly no significant effect on adhesive shear and peel stresses. However, at a fixed common load increasing L, W, and T resulted in a decrease in adhesive shear and peel stresses. A good agreement was found between the experimental and numerical results. [ABSTRACT FROM AUTHOR]

This study provides a promising strategy for designing separator modified materials to solve the shuttle effect of soluble LiPSs in Li-S batteries. [Display omitted] • A composite material consisting of the 3D connected carbon network and ultra-thin NiCo-LDH nanosheets was devised and manufactured. • The DFT calculations further provided a comprehensive demonstration of the synergy adsorption and catalytic conversion processes. • Li-S batteries that were assembled using modified separators demonstrated remarkable electrochemical performance. The shuttle effect of soluble lithium polysulfides (LiPSs) is primarily responsible for the unstable performance of lithium-sulfur (Li-S) batteries, which has severely impeded their continued development. In order to solve this problem, a special strategy is proposed. Specifically, ultra-thin NiCo based layered double hydroxides (named LDH or NiCo-LDH) nanosheets are implanted into a pre-designed 3D interconnected carbon networks (SPC) to obtain porous composite materials (named SPC-LDH). During the operation of the battery, the 3D interconnected porous carbon mesh was the first to rapidly adsorb LiPSs, and then the LDH on the surface of the carbon mesh was used to realize the catalytic conversion of LiPSs. This facilitates the electrochemical conversion reaction between S substances while addressing the "shuttle effect". As a result, the battery maintains a discharge capacity of 1401.9, 1114.3, 975.5, 880.7, 760.4 and 679.6 mAh g−1 at the current densities of 0.1, 0.2, 0.5, 1, 2 and 3C, respectively. After 200 cycles at 2C, the battery's capacity stays at 732.9 mAh g−1, meaning that the average rate of capacity decay is only 0.007 % per cycle. Moreover, in-situ XRD demonstrates the critical function of PP/SPC-LDH separators in inhibiting LiPSs and encouraging Li 2 S transformation. The strong affinity of SPC-LDH for Li 2 S 6 is also confirmed by density functional theory (DFT) calculation, offering more theoretical support for the synergistic adsorption process. This work offers a compelling method to develop modified separator materials that can counteract the "shuttle effect" in Li-S batteries. [ABSTRACT FROM AUTHOR]

Additive manufacturing technology brings new revolutionary potential for the development of carbon fiber reinforced polymer composites. Continuous carbon fiber reinforced composites developed using fused deposition modeling technology have the characteristics of high specific strength, high specific modulus, light weight, and flexible design, which is the solution direction for low-cost, rapid, and flexible application of advanced composite materials in the future. In this paper, the preparation of continuous carbon fiber reinforced polymer composites with continuous carbon fibers as reinforcement and thermoplastic/thermoset as matrix, surface modification and their mechanical properties are investigated, the interfacial characteristics and properties of continuous carbon fiber reinforced polymer composites under different pretreatment processes, auxiliary processes and post-treatment processes are studied, and the connection between the micro-morphology and the mechanical properties of this composite is further analyzed. The direction of defect resolution of continuous carbon fiber reinforced polymer composites fabricated by fused deposition technology is provided, and the future development direction is envisioned. [ABSTRACT FROM AUTHOR]

In this work, we have successfully synthesized the cost-effective, abundant in nature and environmentally friendly SrMoO 4 /MWCNT-PVP by using the co-precipitation technique for hydrogen evolution reaction (HER). Prepared nanocomposites were characterized by XRD, which confirms the formation of tetragonal structure of SrMoO 4 and indexed with JCPDS (01-074-3912). Raman spectra confirm the combination of SrMoO 4 with carbon composite (verified by D and G band 1.02 I D /I G ratio) and its functional group was further analyzed with the help of FTIR spectra. Synthesized product morphology was characterized by using SEM and TEM images, which confirms formation of well-defined dumb-bell shaped nanostructures with the combination of carbon nanotube and also it further confirms the formation of polycrystalline nature of the material. The elemental composition was analyzed by EDS images, which confirms the occurrence of Sr, Mo, O, and C in an appropriate form with a uniform distribution, respectively. MWCNT in SrMoO 4 incorporation led to decrease overpotential of 204 mV and 110 mV/dec Tafel slope of the material, which was examined by the LSV curves and Tafel plot analysis. Electrochemical impedance spectroscopy was also investigated, and it delivered the small charge-transfer resistance of 248 Ω, which further supporting the HER analysis and denoting the promising HER kinetics. Therefore, our work unlocks a new path for the properly tuned nanostructured morphology of metal oxide with carbon composite for electrochemical hydrogen evolution reaction application. [ABSTRACT FROM AUTHOR]

Liquid Crystal Elastomers (LCEs) are renowned for their reversible deformation capabilities. Yet, enhancing their mechanical strength while retaining such flexibility has posed a considerable challenge. To overcome this, we utilized 4D printing to develop an innovative composite of LCE with carbon fiber fabric (LCEC). This approach has notably increased the tensile strength of LCE by eightfold, all the while maintaining its exceptional capacity for reversible deformation. By adjusting the alignment angle between carbon fiber and the LCE printing direction from 0° to 90°, the LCEC demonstrates an array of new deformation patterns, including bending, twisting, wrapping, and S-shaped transformations, which are distinct from pure LCE materials. Our study unveils that LCE composites exhibit deformation processes markedly different from their pure material counterparts, with the ability of pure LCE to sustain tensile strains exceeding 1900%. These findings, previously undocumented and unexplored, represent a substantial contribution to the field of smart materials. Employing finite element analysis, we explored the carbon fiber and LCE matrix dynamics, revealing bending mechanics in LCECs. This combined experimental and simulation approach yields crucial insights for crafting durable, high-strength LCECs with diverse deformational properties, advancing smart material technology. [ABSTRACT FROM AUTHOR]

Graphene oxide-activated carbon (GO–AC) composite with different ratios of GO and AC (0.5/0.5, 0.3/0.7 and 0.1/0.9) were synthesized via direct chemical bonding of them using hydrogen peroxide as a chemical linker and used for selective removal of diclofenac sodium (DCF) and ibuprofen (IBP) from aqueous solutions. The adsorbents' surface morphology, composition, and physicochemical structure of the adsorbents were characterized by FE-SEM, FTIR, BET and XRD analysis. The synthesized composite with a ratio of GO and AC (0.1/0.9) was the most suitable among the synthesized adsorbents for both DCF and IBP adsorption. The optimal working conditions for DCF removal were at pH of 2, contact time of 40 min, initial concentration of 100 mg/L, and temperature of 293 K. For IBP removal, the optimal operating conditions were at pH of 2, contact time of 60 min, initial concentration of 20 mg/L, and temperature of 293 K. The highest adsorption capacities of 0.1/0.9 composite for DCF and IBP were 833.33 and 238.095 mg/g at 298 K, respectively. Isotherm, kinetic, and thermodynamic characteristics were assessed to analyze the adsorption process. The synthesized adsorbent displays high removal efficiency by simple recyclability with low-cost reagent and high selectivity for drug pollutants such as DCF and IBP in single and binary systems. [ABSTRACT FROM AUTHOR]

Autoclave curing is a manufacturing process for high-performance parts based on carbon fiber–reinforced polymers (CFRPs) used for large aircraft parts. Today, this manufacturing process is the reference in terms of quality and, therefore, the manufactured parts' mechanical performance and robustness. However, several parameters can impact the quality of the parts resulting from this process, which requires optimizing key manufacturing parameters. In this study, the effect of autoclave process parameters (i.e., temperature, pressure, and vacuum-pressure) on the glass transition temperature (Tg), laminate compressive modulus (LCM), laminate compressive strength (LCS), and interlaminar shear strength (ILSS) was investigated using three factors, three-level Box–Behnken design (BBD) and response surface methodology (RSM). In addition, the interactions of processing parameters with Tg, LCM, LCS, and ILSS were investigated, making this study an essential investigation for accurately selecting processing parameters. Thus, there is a functionally non-linear relationship between the interaction of the autoclave process parameters. Therefore, these parameters were optimized using RSM with the maximum Tg, LCM, LCS, and ILSS. The optimization and validation of the obtained models were carried out with an average relative error below 3% for all thermomechanical and mechanical properties, indicating that the BBD and optimization were correct. Because of this, the established regression models can accurately predict the Tg, LCM, LCS, and ILSS in autoclaved epoxy/carbon composite laminates. [ABSTRACT FROM AUTHOR]

Lanthanum-modified mesoporous graphite nitride carbon composites (La-g-C3N4) were synthesized using a thermal shrinkage polymerization method. The samples underwent characterization through X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmet–Teller (BET) analysis. The results revealed that the La30-g-C3N4 sample displayed a more porous layered morphology with a uniform pore structure. The BET surface area of the sample was found to be 38.6 m2 g−1, which is 5.8 times higher than that of the undoped sample g-C3N4. The sample exhibited a type IV isotherm, indicating its mesoporous nature with a pore size distribution ranging from 3 to 20 nm. The application of these materials was investigated for the degradation of tetracycline (TC) and acidic fuchsin (AF) in simulated wastewater. The results demonstrated that the La30-g-C3N4 sample exhibited rapid and efficient degradation, along with excellent adsorption capacity for both TC and AF. Within 5 minutes, the degradation efficiency of the La30-g-C3N4 sample for TC and AF was measured to be 83.1% and 74.1%, respectively, with corresponding adsorption capacities of 63.9 mg g−1 and 129.4 mg g−1. The kinetic and thermodynamic analysis of the adsorption process revealed that the adsorption of TC and AF by La30-g-C3N4 followed the quasi-second-order kinetics and Langmuir adsorption isotherm model, indicating a predominantly single-layer chemical adsorption process. Furthermore, the composite material exhibited good cycling stability and maintained excellent adsorption performance even after six repeated uses. [ABSTRACT FROM AUTHOR]

In the present study, we report the synthesis, characterization and assessment of the carbon dioxide adsorption capacity of a composite made of boron nitride and carbon. The material is obtained through a two-step process. In the initial step, ammonia borane is introduced into the pores of a zeolitic imidazolate framework (ZIF-8) using a novel one-pot synthesis method. The ZIF-8 is formed in situ around the ammonia borane molecules, eliminating the need for an infiltration step. The successful confinement of ammonia borane within the ZIF-8 structure is verified through different characterization techniques (IR, XRD, TGA-DSC, and 11B MAS NMR). In the second step, ZIF-8 containing confined ammonia borane is pyrolyzed. Ammonia borane acts as a precursor of boron nitride and the process results in a composite comprising carbon, boron and nitrogen. The composite was subsequently characterized and evaluated as a potential adsorbent for carbon dioxide. With a specific surface area of 56 m2 g−1, the composite demonstrates a CO2 uptake of 1.94 mmol g−1 (or 85.4 mg g−1) when exposed to 1.5 bar of CO2 at 30 °C. This value surpasses reported capacities of other boron nitride-based materials as CO2 adsorbents. When comparing the CO2 adsorption capacity in terms of the specific surface area, a significant enhancement is observed (34 × 10−3 mmol m−2). This suggests that the material provides more active sites for CO2 adsorption, such as polarized B–C, B–N, and C–N bonds. This key factor may be even more important than having a large specific surface area. Therefore, the potential for developing new boron-based materials with enhanced CO2 adsorption capacities lies in increasing both specific surface area and active sites. [ABSTRACT FROM AUTHOR]

This study investigates the influence of extreme environmental conditions on the fracture toughness of halloysite nanotube (HNT)-reinforced carbon fiber-reinforced polymer (CFRP) composites. The focus is on the impact of exposure to high humidity and its effects on the mechanical properties of the composites. The study reveals that exposure to high humidity enhances the fracture toughness of HNT-modified CFRP composites, attributed to the entrapped moisture between HNTs and the polymer matrix. This phenomenon enhances crack bridging and contributes to improved mechanical properties. Furthermore, the HNT-modified composites exhibit superior environmental degradation resistance compared to unmodified composites, demonstrating the potential of HNTs as reinforcement for advanced composite materials. The investigation underscores the significance of considering environmental factors in nanoparticle-reinforced composite design and applications, paving the way for the development of durable, high-performance materials capable of withstanding extreme conditions. The findings emphasize the need for continued research to enhance the durability and reliability of such composites, thereby offering sustainable solutions across a range of applications. This study contributes valuable insights towards the design and optimization of fracture-resistant composite materials for demanding environments. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs), owing to their excellent photoluminescent features, have been extensively studied for physics preparation methods and for biomedical and optoelectronic device applications. The assessment of the applicability of CDs in the production of luminescent polymeric composites used in LEDs, displays, sensors, and wearable devices is being pursued. The present study reports on an original, environmentally friendly, and low-cost route for the production of carbon dots with an average size of 4 nm by laser ablation in liquid. Jointly, to prove the significance of the study for a wide range of applications, a free-standing flexible polyvinyl alcohol (PVA) composite containing photoluminescent carbon dots was manufactured. CDs were prepared using targets of porose charcoal with a density of 0.271 g/cm3 placed in phosphate-buffered saline (PBS) liquid solution and irradiated for 30 min by pulsed IR diode laser. The optical properties of the obtained suspension containing carbon dots were studied with UV-ViS and FTIR spectroscopies. The photoluminescence of the produced carbon dots was confirmed by the emission peak at 480 nm in the luminescence spectrum. A narrow luminescence band with a full width at half-maximum (FWHM) of less than 40 nm could be an asset in spectral emission analysis in different applications. Atomic force microscopy confirms the feasibility of manufacturing CDs in clean and biocompatible environments, paving the way for an easier and faster production route, crucial for their wider applicability. [ABSTRACT FROM AUTHOR]

Carbon fiber-reinforced resin matrix composites find extensive applications across various industries. However, their widespread use also generates significant waste, leading to resource depletion and environmental concerns. Studying the production of composite materials using recovered carbon fiber is imperative to mitigate the environmental impact associated with waste from carbon fiber-reinforced resin matrix composites and optimize resource utilization. In this study, carbon fiber was reclaimed using the microwave pyrolysis–oxidation process. The reclaimed carbon fiber underwent a cutting process to produce shorter carbon fibers tailored to specific requirements, which were then used to fabricate composite plates reinforced with epoxy resin. The mechanical characteristics of the composite were analyzed, along with SEM, XPS, infrared, Raman, and contact angle analyses conducted on the recovered carbon fiber. The test findings suggested minimal variation in the surface morphology of the recovered carbon fiber materials. Post-recovery, an increase in the quantity of oxygen-containing functional groups was observed on the carbon fiber surface. Additionally, the contact angle between the carbon fiber surface and the epoxy adhesive decreased. The mechanical properties of the composite produced from the recovered carbon fiber decreased, including the impact strength, tensile strength, and bending strength, with the impact strength dropping by 24.14%, tensile strength by 15.94%, and bending strength by 8.24%, while maintaining overall reusability, thus paving the way for the comprehensive utilization of carbon fiber resources. [ABSTRACT FROM AUTHOR]

In this paper, the precursors of the target product were prepared using a simple solvothermal method. After pyrolysis of the precursors, a three-dimensional Fe/CuFe2O4@C (referred to as FCC) nanomaterial with a relief texture was successfully prepared, which was employed as a novel catalyst material for activated persulfate (referred to as PS) degradation, tetracycline (referred to as TC), in wastewater. X-ray photoelectron spectroscopy (XPS) revealed that Fe(III) and Cu(II) served as the primary active metal ions, while the formation of a surface carbon shell positively influenced electron transfer during catalytic degradation. A comprehensive investigation was conducted to assess the efficiency of FCC nanocatalysts in degrading TC under various conditions. The results demonstrated that the degradation rate of TC in the 100 min range was about 96% at concentrations of 0.2 g L−1 FCC and 1 mmol L−1 persulfate and pH 7. Quenching experiment results and EPR results consistently indicated that both free radical and non-radical pathways involved in TC degradation by FCC nanomaterials, and sulfate radicals, hydroxyl radicals, superoxide radicals and singlet oxygen were identified to be the main active substances. The degradation intermediates were analyzed by liquid mass spectrometry and toxicology. FCC, as a catalyst exhibiting high catalytic activity, demonstrates superior performance in the activated persulfate degradation of TC. The environmental risk associated with the degradation of intermediate products is significantly lower than that of TC itself. FCC holds significant potential for the degradation of antibiotics in wastewater. [ABSTRACT FROM AUTHOR]

We investigated the recycling process of carbon fibre-reinforced polyimine vitrimer composites and compared composites made from virgin and recycled fibres. The vitrimer matrix consisted of a two-component polyimine-type vitrimer system, and as reinforcing materials, we used nonwoven felt and unidirectional carbon fibre. Various diethylenetriamine (DETA) and xylene solvent ratios were examined to find the optimal dissolution conditions. The 20:80 DETA–xylene ratio provided efficient dissolution, and the elevated temperature (80 °C) significantly accelerated the process. Scaling up to larger composite structures was demonstrated. Scanning electron microscopy (SEM) confirmed effective matrix removal, with minimal residue on carbon fibre surfaces and good adhesion in recycled composites. The recycled nonwoven composite exhibited a decreased glass transition temperature due to the residual solvents in the matrix, while the UD composite showed a slight increase. Dynamic mechanical analysis on the recycled composite showed an increased storage modulus for nonwoven composites at room temperature and greater resistance to deformation at elevated temperatures for the UD composites. Interlaminar shear tests indicated slightly reduced adhesion strength in the reprocessed composites. Overall, this study demonstrates the feasibility of recycling vitrimer composites, emphasising the need for further optimisation to ensure environmental and economic sustainability while mitigating residual solvent and matrix effects. [ABSTRACT FROM AUTHOR]

The four-electron oxidation process of the oxygen evolution reaction (OER) highly influences the performance of many green energy storage and conversion devices due to its sluggish kinetics. The fabrication of cost-effective OER electrocatalysts via a facile and green method is, hence, highly desirable. This review summarizes and discusses the recent progress in creating carbon-based materials for alkaline OER. The contents mainly focus on the design, fabrication, and application of carbon-based materials for alkaline OER, including metal-free carbon materials, carbon-based supported composites, and carbon-based material core–shell hybrids. The work presents references and suggestions for the rational design of highly efficient carbon-based OER materials. [ABSTRACT FROM AUTHOR]

The inductive heating of a CMC susceptor for industrial applications can generate very high process temperatures. Thus, the behavior of a silicon carbide-based matrix with carbon-fiber-reinforced carbon (C/C-SiC) as a susceptor is investigated. Specifically, the influence of fiber length and the distribution of carbon fibers in the composite were investigated to find out the best parameters for the most efficient heating. For a multi-factorial set of requirements with a combination of filling levels and fiber lengths, a theoretical correlation of the material structure can be used as part of a digital model. Multi-physical simulation was performed to study the behavior of an alternating magnetic field generated by an inducing coil. The simulation results were verified by practical tests. It is shown that the inductive heating of a C/C-SiC susceptor can reach very high temperatures in a particularly fast and efficient way without oxidizing if it is ensured that a silicon carbide-based matrix completely encloses the fibers. [ABSTRACT FROM AUTHOR]

Graphite/SiC composites with excellent tribological properties and chemical stability are ideal bearing materials for use in water-lubricated conditions. The composites can be fabricated rapidly by reactive melt infiltration (RMI) with near-net advantages. However, maintaining an adequate carbon content in the matrix after the violent reaction between carbon and liquid silicon is the critical requirement for wear rate and more stable friction coefficient. In this study, a carbon-composite-powder (PFC@G) constructed of graphite particles and glassy carbon derived from phenolic resin, was used as the main carbon source with a larger size (∼200 μm) to improve the carbon content of the graphite/SiC composites. The tribological properties of the composites were measured by a block-on-ring tribometer under water-lubricated conditions. The weight ratio of phenolic resin to graphite particles was adjusted to manipulate the microstructure of PFC@G, which can affect the carbon content of the composites in the course of RMI. The composites with high carbon content (34.47 vol%) were successfully fabricated when the weight ratio is 0.8, which exhibited the most outstanding tribological properties with low friction coefficient (∼0.014) and wear rate (∼10−6 mm3 N−1m−1) at a load of 15 N. [ABSTRACT FROM AUTHOR]

According to the requirement of "structural design and manufacturing feasibility" of the electric vehicle battery pack, the design of carbon fiber composite material instead of metal material is studied in this paper. Firstly, the cross-section performance of the composite battery pack was determined by the principle of equal stiffness. Moreover, the different layups were verified from a manufacturing point of view and the advantages and disadvantages of the three improvements, linear shear, V-shear, and V-shear + linear shear, were compared. Secondly, the three steps of free size optimization, size optimization, and layup sequence optimization were carried out for the lower box to find the lightest structure; the upper box was directly reinforced with a "King" type to alleviate the excessive amplitude. The total mass of the final pack is 14.09 kg, with a weight reduction rate of 56%. Finally, the volume-of-fluid (VOF) method in ANSYS Fluent is chosen to simulate the curing process. The molding results of four injection methods are discussed, while resin viscosity and pressure are considered to find the optimal process parameters. The work in this paper provides a reference for the lightweight application of composite materials in new energy vehicles. [ABSTRACT FROM AUTHOR]

This study is to investigate the effects of random interfacial debonded on the elastic constants of carbon fiber reinforced composites. The results reveal that the interfacial debonded fraction (IDF) significantly effects the elastic constants, and the randomness of interfacial debonded position significantly effects the stress distribution, but different interfacial debonded positions at the same IDF have a negligible effect on the elastic constants. The increase of IDF leads to a gradual increase in the disruption of tandem integrity between fibers and matrix, limiting the capability of the interface to transfer loads more significantly. [ABSTRACT FROM AUTHOR]

A Fe-Co dual-metal co-doped N containing the carbon composite (FeCo-HNC) was prepared by adjusting the ratio of iron to cobalt as well as the pyrolysis temperature with the assistance of functionalized silica template. Fe1Co-HNC, which was formed with 1D carbon nanotubes and 2D carbon nanosheets including a rich mesoporous structure, exhibited outstanding oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalytic activities. The ORR half-wave potential is 0.86 V (vs. reversible hydrogen electrode, RHE), and the OER overpotential is 0.76 V at 10 mA cm−2 with the Fe1Co-HNC catalyst. It also displayed superior performance in zinc–air batteries. This method provides a promising strategy for the fabrication of efficient transition metal-based carbon catalysts. [ABSTRACT FROM AUTHOR]

Needle-punched carbon/carbon (NP C/C) composite is widely used in rocket-engine nozzles and re-entry vehicles. Recyclable technology expedited the research on repeated oxidation and residual mechaincal properties of thermal-protection materials. In this study, the critical longitudinal compression strengths before and after oxidation are derived based on the Timoshenko beam theory. Three repetitions of short-term oxidation cycles and compression experiments are investigated. The average oxidation rate of this composite was 5∼6% in 10 min and kept linear increase. In-plane and out-of-plane compressive strengths of NP C/C composite diminish quasi-linearly due to oxidation at 1000°C, with their moduli decreasing in a periodically slow-sharp pattern. After three oxidation cycles, the levels of residual in-plane modulus and strength were 55.20% and 56.89%, respectively, while the resudual out-of-plane modulus and strength were 44.65% and 47.23%, respectively. The results showed that the material exhibited the pesudo-plastical behaviour after oxidation, cracks grew along the punched conical structures formed by the punching technology. In-plane and out-of-plane modulus were more sensitive than their strengths after first oxidation cycle. [ABSTRACT FROM AUTHOR]

The aim is to investigate the advantages of blending affordable, lightweight, and biodegradable plant fibers with carbon fibers compared to single‐fiber composites. Adding ramie fiber to carbon fiber to produce carbon‐ramie fiber (CRFRP) and ramie–carbon fiber‐reinforced composites (RCFRP), and prepare pure carbon fiber and pure ramie fiber composites (carbon fiber‐reinforced composite [CFRP], RFRP) for comparison. Then, their static and dynamic mechanical properties (stretching, bending, low speed, and high‐speed impact) are illustrated. The results show that the CRFRP and RCFRP hybrid composites exhibit excellent properties, although slightly lower than the CFRP composites, but much higher than the RFRP, and the CRFRP composites show a slightly higher performance advantage over the RCFRP composites. Compared with CFRP composites, the tensile strength, flexural strength, and high‐speed impact peak load of CRFRP composites are reduced by 24.07%, 0.12%, and 5.44%, respectively, and the RCFRP composites are reduced by 32.11%, 45.82%, and 37% respectively. The results of the low‐speed impact test also show that the two mixed composites have good fracture elongation and stiffness. Therefore, the mechanical properties of CRFRP and RCFRP composites are comparable to those of CFRP composites, which not only reduces the material cost and reduce weight of the composite but also boosts the solution of the two‐carbon problem. Highlights: Innovative combination with natural fibers and synthetic fibers to fabricate hybrid fiber‐reinforced composites.The static (tensile and flexural) and dynamic (low‐speed and high‐speed impact) mechanical properties of CRFRP, RCFRP, CFRP, and RFRP composites are measured.The mechanical properties of CRFRP and RCFRP composites are comparable to those of CFRP composites. [ABSTRACT FROM AUTHOR]

Continuous hybrid fiber‐reinforced composites (CHFRCs) have excellent mechanical properties, and strong designability, and are widely used in aerospace and other fields. The development of 3D printing technology offers novel directions in the design and manufacture of complicated CHFRC components in aerospace. For this purpose, this study focused on the design and characterization of hybrid continuous fiber‐reinforced composites prepared by 3D printing. The rapid mold‐free integrated manufacturing of hybrid continuous Kevlar/carbon fiber‐reinforced composites was realized by coaxial hybrid 3D printing technology. The regulation and mechanism of tensile properties of 3D‐printed CHFRCs were elucidated. The tensile strengths of 3D‐printed CHFRCs were enhanced by up to 15.3% and 92.4%, respectively, compared to single continuous carbon and Kevlar fiber composites produced by the same process parameter. A new tensile modulus predicting method for 3D‐printed CHFRCs was proposed. It mitigated the influence of complex interfacial characteristics on mechanical property prediction and achieved precise estimation of the tensile modulus of 3D‐printed CHFRCs. This will provide the theoretical support for the application and development of 3D‐printed CHFRCs. Highlights: Mouldless rapid manufacturing of coaxial hybrid fiber composites achieved.The tensile strength and modulus of the fiber composites are greatly improved.A new prediction method for the tensile modulus of 3D‐printed composites is proposed. [ABSTRACT FROM AUTHOR]

This research conducts a comprehensive experimental and numerical analysis of carbon fiber composite laminates under low‐velocity impact conditions. Split Hopkinson Pressure Bar (SHPB) was employed to conduct impact testing on laminates with two layup sequences (03/+45/−45s and 03/903s) under impacts ranging from 2 to 6 J. For assessing damage in laminates, a comprehensive progressive damage model and a simplified model were developed. The primary distinction between these models lies in the fact that the former incorporates the strengthening effect of compression on the delamination behavior, while the latter does not. Both models produce a good agreement with experimental results in terms of force–time, force–displacement curves, and absorbed energies. However, notable differences were noted in the predicted internal damage; the simplified model was underpredicted in terms of damage size and distribution compared to the comprehensive progressive damage model. Highlights: Impact tests were conducted on 03/+45/−45s and 03/903s composites.In order to simulate damage caused by impacts in laminates, an energy‐based damage model was created, and cohesive elements were utilized to model interlaminar delamination.The strengthening effect of compression was explored.Distinct damage criteria were established for two cases.Damage detection of composites by x‐rays. [ABSTRACT FROM AUTHOR]

A general strategy for developing nitro compounds hydrogenation catalysts, involving constructing interfaces of transition-metal compounds with nitrogen-doped carbon, is proposed. The interfacial bonds in the developed catalysts can modulate the electronic structure of active sites, and hence significantly expose the active sites and enhance mass transport. Specifically, optimal Cr2O3/NC, Mo2C/NC, V2O3/NC and WOx/NC catalysts provide impressive performances with a conversion rate of 99% and a nearly 100% selectivity for hydrogenating nitro compounds. [ABSTRACT FROM AUTHOR]

Epoxy thermosets are used in many fields because of their outstanding properties. However, commercial epoxy thermosets are flammable, so epoxy resins with excellent flame retardant properties need to be prepared. In recent years, carbon fiber epoxy composites have been widely used in aerospace and other high-tech fields due to their high strength and excellent performance. With the increased use of carbon fiber epoxy composites, the recycling of carbon fibers is an important issue. Herein, a biobased epoxy vitrimer (TVEP/DFDA) containing a Schiff base structure was successfully prepared by utilizing vanillin, tyramine and furfurylamine. Moreover, carbon fiber epoxy composites (CF-TVEP/DFDA) were successfully prepared. The TVEP/DFDA composite has better mechanical properties than DGEBA/DDM and excellent flame-retardant performance. The limiting oxygen index (LOI) of TVEP/ DFDA was 28.5%, and TVEP/DFDA achieved a UL-94 V-0 rating. Heat hazards and smoke hazards are sources of danger in fires. According to the cone calorimetry test, compared with those of DGEBA/ DDM, the heat release rate, total heat release and total smoke production of TVEP/DFDA decreased by 73.9%, 52.6% and 56.6%, respectively. The significantly reduced heat and smoke production indicate that TVEP/DFDA has a lower combustion intensity and better fire safety than DGEBA/DDM. CF-TVEP/DFDA also exhibited excellent flame-retardant performance, with a high LOI of up to 45% and a UL-94 V-0 rating. However, the CF-DGEBA/DDM cannot pass the vertical burning test. TVEP/ DFDA has excellent stability under different solvents and can be degraded under acidic conditions. This work describes a strategy for recycling carbon fibers by immersion in a hydrochloric acid solution. The recycled carbon fibers exhibit surface morphologies, chemical structures and mechanical properties similar to those of virgin carbon fibers. [ABSTRACT FROM AUTHOR]

In this paper, a series of iron oxide/reduced graphene oxide/carbon nanotube composites (K3‐Fe2O3‐rGO/CNT) with well‐dispersedFe2O3 particles are prepared by in situ reaction and then heat‐treatment, and its electrochemical and battery performancesare studied as the anode material of lithium‐ion batteries. The results show that the introduction of reduced graphene oxide/carbon nanotube (rGO/CNT) improves the electrochemical and battery performances of the prepared electrode material. In particular, the K3‐Fe2O3‐rGO/CNT (30 %) composite material has a reversible capacity of 1559 mAh g−1 after 100 charge/discharge cycles at 100 mA g−1. And its specific discharge capacityis 641.1, 639.7, 609.5, 578.6 and 543 mAh g−1at the current density of 100, 200, 500, 1000 and 2000 mA g−1, respectively,with 84.7 % of capacity retention even with a 10 times increase in current density. The research of charge storage indicates that the electrochemical process is a mixed control process of diffusion and capacitance. The improved electrochemical and battery performancesfor the composite electrode material can be attributed to the enhanced dispersion of the Fe2O3 and the enhanced conductive network provided by rGO/CNT composite carbon. It makes a promising way to prepare high performance of anode material for lithium‐ion battery. [ABSTRACT FROM AUTHOR]

The WC-based composites incorporated with different concentrations of TaC 0.8 were solidified by using ball milling and spark plasma sintering (SPS). The impact of TaC 0.8 content on the densification, phase composition, microstructure and mechanical properties of WC-TaC 0.8 composites was evaluated. The major constitutions of WC-TaC 0.8 composites were WC matrix, (W 1−x , Ta x)C n solid solution and W 2 C phase. The adequate amounts of TaC 0.8 additive had promoter function on the generation of W 2 C and the densification of WC-based composites through carbon vacancies. The (W 1−x , Ta x)C n and W 2 C phases were uniformly dispersed in the WC matrix, effectively bringing a refinement of WC grains. There were the coherent interface of WC (0 1 ̅ 10)/W 2 C (10 1 ̅ 0) and semi-coherent interface of (W 1−x , Ta x)C n (200)/WC (10 1 ̅ 1) in the WC-7.5 wt%TaC 0.8 (WTa7.5) composite. The nearly-full densified WTa7.5 composite (99.3%) rendered the best overall mechanical properties, featuring high hardness of 24.9 GPa and high fracture toughness of 8.3 MPa·m1/2. The high fracture toughness was justified by several factors including highly dense and fine microstructure, coherent and semi-coherent interfaces, and a combination of transgranular and intergranular fracture, as well as crack deflection and crack bridging. [ABSTRACT FROM AUTHOR]

Large-tow carbon fiber (LCF) meets the low-cost requirements of modern industry. However, due to the large and dense number of monofilaments, there are problems with uneven and insufficient infiltration during material preparation. The permeability of large-tow carbon fibers can be used as a two-scale expression of resin flow during infiltration, making it an important factor to consider. This paper provides support for the study of pore formation. A two-dimensional model of randomly bundled large-filament carbon fibers is generated based on scanning electron microscope (SEM) maps. Microstructure size parameters are obtained, and a semi-analytical model of the transverse permeability of large-filament-bundled carbon fibers is established. Permeability values are then obtained. The analysis shows that the monofilaments in the tow are arranged randomly, and their periodic arrangement cannot be used to calculate permeability. Additionally, the number of monofilaments in a carbon fiber tow of the same volume fraction affects the permeability of the tow. Therefore, the permeability model of large-tow carbon fibers is reliable. [ABSTRACT FROM AUTHOR]

In efforts to achieve the goal of reducing ship emissions in the fight against climate change, reducing fuel consumption by making ships lighter is stated as one of the solutions. In this study, the possibilities of making composite equivalents of propellers, which are the most complex ship elements and traditionally produced from metal materials, are investigated with the advantages of additive manufacturing, which offers a rapid production opportunity for such forms. In this way, a lighter composite propeller and, therefore, a lighter ship will be achieved, and negative environmental impacts, especially harmful emissions, will be reduced. In the study, a 1/14-scale ship propeller was produced through the material extrusion method of additive manufacturing using an HDPE composite containing long carbon fiber with a 15% weight fraction. An attempt to reduce flexibility with an epoxy-carbon fabric prepreg coating was made, as the flexibility has negative effects on the performance of the produced propeller. The propeller tunnel test showed that the applied carbon fabric epoxy prepreg helped to improve the propeller's performance by decreasing the flexibility of the propeller and reducing the deformation at the tips. At the same time, the propeller weight was decreased by 60% compared to its metal counterparts. [ABSTRACT FROM AUTHOR]

[Display omitted] • FeNb 2 O 6 /3D interconnected N -doped carbon cages were synthesized by methanol-induced assembly and pyrolysis strategy. • The methanol evaporation promotes the assembly and crosslinkage of ZIF-8, resulting in 3D interconnected cage-like superstructure. • The 3D structure provides a spacious surface area and abundant defects for interfacial mass and electron transfer. • FeNb 2 O 6 /NICC showed excellent performances of the ORR and Zn-air battery. Three-dimensional (3D) hollow carbon is one of advanced nanomaterials widely applied in oxygen reduction reaction (ORR). Herein, iron niobate (FeNb 2 O 6) nanoparticles supported on metal-organic frameworks (MOFs)-derived 3D N -doped interconnected open carbon cages (FeNb 2 O 6 /NICC) were prepared by methanol induced assembly and pyrolysis strategy. During the fabrication process, the evaporation of methanol promoted the assembly and cross linkage of ZIF-8, rather than individual particles. The assembled ZIF-8 particles worked as in-situ sacrificial templates, in turn forming hierarchically interconnected open carbon cages after high-temperature pyrolysis. The as-made FeNb 2 O 6 /NICC showed a positive onset potential of 1.09 V and a half-wave potential of 0.88 V for the ORR, outperforming commercial Pt/C under the identical conditions. Later on, the as-built Zn-air battery with the FeNb 2 O 6 /NICC presented a greater power density of 100.6 mW cm−2 and durable long-cycle stability by operating for 200 h. For preparing 3D hollow carbon materials, this synthesis does not require a tedious removal process of template, which is more convenient than traditional method with silica and polystyrene spheres as templates. This work affords an exceptional example of developing 3D N -doped interconnected hollow carbon composites for energy conversion and storage devices. [ABSTRACT FROM AUTHOR]

[Display omitted] Lithium ion capacitors (LICs) are a new generation of energy storage devices that combine the super energy storage capability of lithium ion batteries with the satisfactory power density of supercapacitors. The development of high-performance LICs still faces great challenges due to the unbalanced reaction kinetics at the anode and cathode. Therefore, it is an inevitable need to enhance the electron/ion transfer capability of the anode materials. In this paper, to obtain a superior-rate and high-capacity Ni 3 S 2 -based anode, highly conductive Ti 3 C 2 T x MXene sheets were introduced to sever as the carrier of Ni 3 S 2 nanoparticles and simultaneously an amorphous carbon layer which coats onto the surface of Ni 3 S 2 nanoparticles was in-situ generated by the carbonization of dopamine reactant. The as-synthesized Ni 3 S 2 /Ti 3 C 2 T x /C composite exhibits a high specific surface area (112.6 m2/g) because of the addition of Ti 3 C 2 T x that can reduce the aggregation of Ni 3 S 2 nanoparticles and the in-situ generated amorphous carbon layer that can suppress the growth of Ni 3 S 2 nanoparticles. The Ni 3 S 2 /Ti 3 C 2 T x /C anode possesses a remarkable reversible discharge specific capacity (626.0 mAh/g under 0.2 A/g current density), which increases to 1150.8 mAh/g after 400-cycle charge/discharge measurement at the same measurement condition indicating eminent cyclability, along with superior rate capability. To construct a superior-performance LIC device, a sterculiae lychnophorae derived porous carbon (SLPC) cathode with an average discharge specific capacity of 73.4 mAh/g@0.1A/g was prepared. The Ni 3 S 2 /Ti 3 C 2 T x /C//SLPC LIC device with optimal cathode/anode mass ratio has a satisfactory energy density ranging from 32.8 to 119.1 Wh kg−1 at the corresponding power density of 8799.4 to 157.5 W kg−1, together with a prominent capacity retention (95.5 %@1 A/g after 10,000 cycles). [ABSTRACT FROM AUTHOR]

Because of the high demand for carbon fiber reinforced polymer (CFRP) materials across all industries, the reuse and/or recycling of these materials (rCFRP) is necessary in order to meet the principles of the circular economy, including recycling and reuse. The objective of this study is to estimate the lifespan of thermoplastic matrix composite materials reinforced with waste materials (CFRP), which undergo only a mechanical cutting process. This estimation is carried out through the thermal decomposition of polymers, including polymer matrix composite materials, which is a complex process due to the numerous reactions involved. Some authors calculate these kinetic parameters using thermogravimetric analysis (TGA) as it is a quick method, and it allows the identification of gases released during decomposition, provided that the equipment is prepared for it. This study includes a comparison between polyamides 11 and 12, as well as between polyamide composite materials with carbon fiber (CF) and polyamides reinforced with CF/epoxy composite material. The latter is treated with plasma to improve adhesion with polyamides. The behavior of weight as a function of temperature was studied at speeds of 3, 6, 10, 13, 17, and 20 °C/min, finding stability of the polyamides up to a temperature of 400 °C, which was consistent with the analysis by mass spectroscopy, where gas evolution is evident after 400 °C. The estimation of the lifespan was carried out using two different methods including the Toop equation and the free kinetics model (MFK). The energy of the decomposition process was determined using the MFK model, which establishes the energy as a function of the degree of conversion. It is estimated that at 5% decomposition, mechanical properties are lost. [ABSTRACT FROM AUTHOR]

Woven flax-carbon hybrid polyamide biocomposites offer a blend of carbon fibers' mechanical strength and flax's environmental advantages, potentially developing material applications. This study investigated their thermal behavior, degradation kinetics, and durability to water uptake and relative humidity exposure and compared them with pure flax and carbon composites with the same matrix. The hybrid composite exhibited intermediate water/moisture absorption levels between pure flax and carbon composites, with 7.2% water absorption and 3.5% moisture absorption. It also displayed comparable thermal degradation resistance to the carbon composite, effectively maintaining its weight up to 300 °C. Further analysis revealed that the hybrid composite exhibited a decomposition energy of 268 kJ/mol, slightly lower than the carbon composite's value of 288.5 kJ/mol, indicating similar thermal stability. Isothermal lifetime estimation, employing the activation energy (Ed) and degree of conversion facilitated by the Model Free Kinetics method, indicated a 41% higher service life of the hybrid laminate at room temperature compared to the carbon laminate. These insights are crucial for understanding the industrial applications of these materials without compromising durability. [ABSTRACT FROM AUTHOR]

A series of metal- and silica-containing carbon-based nanocomposites were synthesized by pyrolysis of a resorcinol–formaldehyde polymer modified with metal oxide/silica nanocomposites (MxOy/SiO2, where M = Mg, Mn, Ni, Cu and Zn) via the thermal oxidative destruction of metal acetates adsorbed on highly dispersed silica (A380). The concentration of metals was 3.0 mmol/g SiO2. The phase composition and morphological, structural and textural properties of the carbon materials were analyzed by X-ray diffraction, SEM, Raman spectroscopy and low-temperature N2 adsorption. Thermal decomposition under a nitrogen atmosphere and in air was analyzed using TG–FTIR and TG–DTG–DSC techniques to determine the influence of the filler on the decomposition process. The synthesized composites show mesoporous structures with high porosity and narrow pore size distributions. It could be shown that the textural properties and the final composition of the nanocomposites depend on the metal oxide fillers of the precursors. The data obtained show that nickel and copper promote the degree of graphitization and a structural order with the highest porosity and largest specific surface area of the hybrid composites. The good adsorption properties of the obtained materials were shown for the recovery of p-chlorophenol and p-nitrophenol from aqueous solutions. [ABSTRACT FROM AUTHOR]

Due to the unique properties of titanium (Ti) and its alloys, it has a particularly wide range of applications in aerospace, automotive, medical and other fields. However, the problems of low surface hardness, high friction coefficient and low wear resistance of Ti alloys limit its development to a certain extent. The destruction of Ti and its alloys often occurs on the surface of materials such as wear damage, corrosion, and oxidation resistance. Therefore, the exploration and application of surface strengthening technology is particularly important. The cathodic plasma electrolytic deposition (CPED) technology, as a surface modification technology, can achieve better adhesion and facilitate the material to achieve better comprehensive performance. This paper briefly introduces the basic concepts, principles and development progress of CPED. Starting from the preparation of ceramic coatings, metal coatings, diamond-like carbon films and composite coatings, it summarizes the application of CPED in Ti and its alloys. Applications in alloys to improve thermal oxidation resistance, wear resistance, corrosion resistance, and film-based adhesion. At the end, its development in the new era environment is prospected. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Energy transformation is imminent, and hydrogen energy is one of the important new energy sources. One of the keys to increasing the rate of hydrogen evolution during electrolysis is the use of high‐performance catalysts for oxygen evolution reactions (OER). Single‐atom alloys (SAAs) have garnered significant attention because they partially reduce costs and combine the advantages of both single‐atom catalysts (SACs) and alloy catalysts. Herein, an efficient pyrolysis strategy based on a mixing and drying process is designed to anchor ultra‐small Co cluster particles, combined with Ru single atoms dispersed on nitrogen‐doped ultra‐thin carbon nanosheets (Ru1Co SAA/NC). The prepared electrocatalyst exhibits superior OER activity and superb stability, demonstrating an overpotential of 238 mV for OER with a current density of 10 mA·cm–2 in 0.5 mol/L H2SO4. And we also utilized in‐situ XAS to detect the oxidation state of Ru sites during OER. All in all, this method achieves cost reductions and efficiency improvements through the design of SAAs, offering new prospects for the structural transformation of clean energy. [ABSTRACT FROM AUTHOR]