Multi-walled Carbon Nanotubes Research Articles

Triazine-Based Large-Sized Single-Crystalline Two-Dimensional Covalent Organic Framework for High-Performance Lithium-Ion Batteries.

A large-sized single crystalline 2D COFs with excellent crystallinity and stability was prepared through the traditional thermal solvent method. The electrochemical performance can be significantly enhanced using a straightforward hybrid approach that involves in situ growth of the 2D COFs on multi-walled carbon nanotubes (MWCNTs). Both the advantages of COFs and CNTs are mutually enhanced. The single-crystalline feature of the obtained COFs improves the structural integrity and brings excellent chemical and electrochemical stabilities for lithium-ion battery applications. The resultant COF-CNT core-shell hybrids greatly improved the conductivity and demonstrated excellent lithium-ion storage performance with a high capacity of 228 mAh g-1 (0.2 A g-1).

Exploring the mechanical and thermal properties of rubber-based nanocomposite: A comprehensive review

Abstract The emergence and progression of synthetic rubber have paved the way in variegated prospects across various engineering and technological fields. Nonetheless, its inherent limitations such as poor mechanical and thermal properties including wear resistance, poor tensile strength, and lower thermal conductivity, as evident in styrene butadiene rubber and silicone rubber, have constrained its utility in numerous load-bearing scenarios. This limitation has been addressed by incorporating specific nanofillers into various rubber compositions, resulting in promising outcomes up to a certain threshold. Many nanofillers were trialed, such as graphite oxide, aluminum oxide, carbon nanotubes, and boron nitride. However, an attempt should be made to explore the disparity in dimensional attributes of nanofillers and their effect on different properties of rubber, thereby delineating the scope for future research. The exploration of dimensionally distinct nanofillers, such as 1D multiwalled carbon nanotubes and 2D graphene, can overcome these limitations and augment rubber’s mechanical properties and thermal properties. The study also delineates the scope of future research, which should be focused on optimizing the nanofillers’ dispersion and interfacial bonding within the rubber matrix by trying dimensionally different nanofillers.

Dielectric, low‐frequency noise and mechanical properties of hybrid carbon nanotubes/graphene nanoplatelets epoxy composites

AbstractThis study analyzes the electrical, microwave (26–37 GHz), low‐frequency (20 Hz–10 kHz) noise, and mechanical properties of epoxy hybrid composites filled with multi‐walled carbon nanotubes (MWCNT) and graphene nanoplatelets (GNP). The system's percolation threshold was around 0.25 vol.% MWCNT, while the electromagnetic properties were almost independent of GNP concentration. The composites are shown to be suitable for electromagnetic shielding in the 26–37 GHz range, with microwave absorption increasing as the total nanocarbon concentration rises. The electrical transport in these composites is governed by one‐dimensional Mott hopping at low temperatures (below 245 K) and redistribution effects above room temperature. The low‐frequency voltage noise spectra of the composites are predominant of the 1/f component, with noise spectral density proportional to Ub, where the exponent b is close to 2, indicating noise caused by resistance fluctuations. The optimal electromagnetic properties are near 0.5 vol.% MWCNT and 0.25 vol.% GNP concentrations. The tensile elastic modulus and yield strength showed the highest increases at 0.25/0.25 loading, with gains of 40.43% and 16.77%, respectively, compared to neat epoxy. Fracture toughness and energy release rate increased with adding 0.25 vol.% GNP, while Charpy impact strength improved with higher MWCNT loading.Highlights Percolation threshold in hybrid MWCNT/GNP composites is close to 0.25 vol.% MWCNT Low‐frequency voltage noise spectra of the composites are 1/f type

Using Nanomaterials and Arbuscular mycorrhizas to Alleviate Saline–Alkali Stress in Cyperus esculentus (L.)

Saline–alkali (SA) stress is an abiotic stress that exists widely in the natural environment, seriously affecting the growth and development of crops. Tiger nut (Cyperus esculentus L.), a perennial herb of Cyperus in Cyperaceae, is considered a pioneer crop for growing and improving SA land due to its excellent adaptability and SA tolerance. This study is the first to evaluate the SA tolerance of tiger nut and the alleviative effects of nanomaterials (nano-selenium and multi-walled carbon nanotubes) and arbuscular mycorrhizas (AMs) on SA stress. The results showed that the seedling fresh weight of tiger nut was the most suitable parameter to describe the dose–response effect of plant growth with increased SA concentration. Based on the log-logistic dose–response curve, the GR50 values of NaCl and NaHCO3 (the concentrations causing a 50% reduction in seedling fresh weight) were determined to be 163 mmol L−1 and 63 mmol L−1, respectively. Under these stresses, the exogenous application of MWCNTs at 100 mg L−1 or Nano-Se at 10 mg L−1 showed that the effect of SA on tiger nut was alleviated. Field evaluation further showed that the exogenous application of MWCNTs, Nano-Se, or AMs could effectively alleviate SA stress on tiger nut. Compared to the untreated control, the application of these substances significantly improved the plant photosynthesis-related parameter, antioxidant enzyme activity, plant height (height: 66.0–69.9 cm), tuber yield (yield: 23.4–27.4 g plant−1), and oil quality of tiger nut under SA stress. The results of this study indicate that the application of MWCNTs, Nano-Se, or AMs, to tiger nut can alleviate SA stress and maintain seed yield, providing the possibility of using these nanoparticles to improve the SA tolerance of tiger nut in agricultural practice.

Investigation of Some Crown Ether Compounds for Electrochemical Determination of Dopamine

In this study, the use of three different crown ether-modified electrodes prepared by electropolymerization of different crown ether compounds (CE1, CE2 and CE3) on multi-walled carbon nanotube (MWCNT) modified glassy carbon electrode (GCE) surfaces was investigated for electrochemical dopamine determination. The number of cycles during the electropolymerization of crown ethers and the pH of the buffer solution were optimized. Under optimum conditions, the sensitivities of MWCNT-modified GCE and crown ether-MWCNT-modified electrodes were determined in the range of 4.0×10-6 – 5.7×10-4 M dopamine. The sensitivity of MWCNT/GCE was found to be 6.71 µA mM-1, while the sensitivities of CE1/MWCNT/GCE, CE2/MWCNT/GCE and CE3/MWCNT/GCE were 19.53, 16.32 and 20.80 µA mM-1, respectively. The performance characteristics of the crown ether-MWCNT-modified electrodes such as detection limit, quantification limit, reusability and reproducibility were also investigated. The study showed that crown ether compounds significantly enhanced the electrochemical response in dopamine determination.

Pt Nanoparticles on Multi-Walled Carbon Nanotubes with High CO Tolerance for Methanol Electrooxidation

Anode catalysts are important for direct methanol fuel cells (DMFCs) of energy conversion. Herein, we report a novel strategy by ethylene glycol-based deep eutectic solvents (EG-DESs) for the fabrication of a multi-walled carbon nanotubes (MWCNTs)-supported Pt nanoparticles catalyst (referred to as Pt/CNTs-EG-DES). The Pt/CNTs-EG-DES catalyst provides an increased electrochemically active surface area (ECSA) and shows remarkably improved electrocatalytic performance towards methanol oxidation reaction compared to Pt/CNTs-W (fabricated in water) and commercial Pt/C catalysts. The improved performance is attributed to the generation of more Pt–O bonds which change the electronic states of the Pt atoms and the special node structure that obtains more active sites for a high CO resistance. This study suggests an effective synthesis strategy for Pt-based electrocatalysts with high performance for DMFC applications.

The Effect of a Combination of Multiwalled Carbon Nanotubes (MWCNT), Gold Nanoparticles (AuNPs), and Silica Microspheres (Si) on the Detection of 17α -Ethinylestradiol (EE2)

17α-ethinylestradiol (EE2) is a female synthetic hormone with high estrogenic activity that can disrupt the environment, which can lead to dire health problems. The current standard method is very time-consuming and expensive, so the objective of this study is to develop chemical sensors that are faster and much cheaper to detect EE2 in water samples. In this work, an electrochemical sensor using a combination of multiwall carbon nanotubes (MWCNT), gold nanoparticles (AuNPs), and silica microspheres (Si) as a modified electrode is reported to demonstrate 17α-ethinylestradiol (EE2) detection using electrochemical analysis. MWCNT-AuNPs, MWCNT-Si, and Si-AuNPs are prepared for the development of this chemical sensor by depositing each material on the carbon electrode by using the drop casting method. The resistance and conductivity of MWCNT-AuNPs, MWCNT-Si, and Si-AuNPs modified electrodes demonstrated stable electrochemical current responses towards the detection of EE2. It demonstrates that when MWCNTs and AuNPs are combined with Si, the sensitivity and R2 value improves at EE2 concentrations ranging from 10 to 50 μM, respectively.

Neuron-Inspired Flexible Phase Change Materials for Ambient Energy Harvesting and Respiration Monitoring.

The global energy crisis and climate change pose unprecedented challenges. Wearable devices with personal thermoregulation and energy harvesting hold great promise for achieving energy savings and human thermal comfort. Here, inspired by neurons, a novel phase change material (PCM) is reported for efficient energy harvesting and respiratory monitoring via a self-assembly strategy. The use of gum arabic (GA) enabled the encapsulation of polyethylene glycol (PEG) and the targeted distribution of carboxylated multi-walled carbon nanotubes (cMWCNTs) simultaneously in poly (ethylene vinyl acetate) (EVA) matrix. The material exhibits an outstanding toughness value of 14.88MJ m-3 and high elongation at a break of 565.67%, exhibiting remarkable flexibility. The material with sufficient melting enthalpy (71.11 J g-1) demonstrates high photothermal conversion efficiency (95.27%) under 808nm laser irradiation (105mW cm-2). In addition, due to the synergistic effect of GA and PEG, especially the formation of microdome structures on the surface, the material demonstrates ultrasensitive humidity responsiveness for respiratory monitoring with high precision, excellent repeatability, and fast response/recovery time (50.4/50.5ms). Notably, it shows great potential for moisture-electric generators (MEGs) with the function of non-contact sensing. This material opens the path toward next-generation wearable devices in energy conversion and health monitoring.

Design and development of low‐weight and high‐strength electromagnetic shielding nanocomposite in a microwave frequency range

AbstractIn this novel work, we fabricated the multiwalled carbon nanotubes (MWCNTs)/polypyrrole (PPy) nanocomposite by employing the novel ultrasonic dual mixing (UDM) method. Subsequently, the atomistics and structural characterizations of the fabricated MWCNT/PPy nanocomposite (PM) were performed using SEM, Raman, and XRD. Furthermore, we experimentally evaluated the mechanical properties of the fabricated PM by reinforcing the PPy matrix with MWCNTs at different wt.%. The experimental study of PM shows that the mechanical properties depend upon the amount and dispersion quality of MWCNTs in the PPy matrix. In order to validate the experimental outcomes, the conservative fully coupled finite element (FE) models were developed using the ANSYS Workbench and novel FEAST software. The electromagnetic interference (EMI) shielding effectiveness (SE) of developed PM was also calculated at different thicknesses of PM by taking the effect of SE due to absorption (SEA) and SE reflection (SER) in the microwave frequency range of the C‐band (5.37–8.2 GHz) into consideration. The total SE (SET), the cumulative sum of SEA and SER, is the strong function of the thickness of the PM. Additionally, our study's outcomes reveal that as the thickness of the PM increased, the SET also increased by dominating the SEA rather than the SER. The SET value of 75 dB was observed for a sample with a thickness of 3 mm, indicating a high level of shielding. Thus, material becomes a highly attractive option for achieving high‐performance EMI SE in the C‐band for satellite communications, Wi‐Fi devices, weather radar systems, surveillance, and cordless telephones. A complex permittivity and permeability were also studied using the Nicolson–Ross–Weir (NRW) method to understand the mechanism behind the EMI SE.Highlights Nanocomposite fabricated using the novel ultrasonic dual mixing method. FE models were developed to validate experimental results. The EC and EMI SE are improved with the increase in the sample thickness. Absorption, rather than reflection, dominated the shielding mechanism. SE was observed dB with good mechanical properties.

Multifunctional 3D-Printed Thermoplastic Polyurethane (TPU)/Multiwalled Carbon Nanotube (MWCNT) Nanocomposites for Thermal Management Applications

In this work, multiwalled carbon nanotubes (MWCNTs) were melt-compounded into a novel thermal energy storage system consisting of a microencapsulated paraffin, with a melting temperature of 6 °C (M6D), dispersed within a flexible thermoplastic polyurethane (TPU) matrix. The resulting materials were then processed via Fused Filament Fabrication (FFF), and their thermo-mechanical properties were comprehensively evaluated. After an optimization of the processing parameters, good adhesion between the polymeric layers was obtained. Field-Emission Scanning Electron Microscopy (FESEM) images of the 3D-printed samples highlighted a uniform distribution of the microcapsules within the polymer matrix, without an evident MWCNT agglomeration. The thermal energy storage/release capability provided by the paraffin microcapsules, evaluated through Differential Scanning Calorimetry (DSC), was slightly lowered by the FFF process but remained at an acceptable level (i.e., >80% with respect to the neat M6D capsules). The novelty of this work lies in the successful integration of MWCNTs and PCMs into a TPU matrix, followed by 3D printing via FFF technology. This approach combines the high thermal conductivity of MWCNTs with the thermal energy storage capabilities of PCMs, creating a multifunctional nanocomposite material with unique thermal management properties.

Numerical investigation of heat and mass transfer of SWCNT/MWCNT‐water suspension over a porous stretching sheet using Sisko fluid model

AbstractThis study presents a comprehensive numerical computation of heat‐mass transfer characteristics of single‐walled carbon nanotube (SWCNT)/multi‐walled carbon nanotube (MWCNT)‐water suspension flow over a porous stretching sheet with an inclined magnetic field. The governing equations for fluid flow characteristics are formulated using the Sisko fluid model to capture the Newtonian and non‐Newtonian behavior of the nanotube‐water mixture. The nonlinear coupled partial differential equations are converted into nonlinear dimensionless coupled ordinary differential equations using suitable similarity transformations. These equations are solved using MATLAB by implementing the four‐stage Lobatto IIIa formula. The comprehensive set of computations is performed to explore the influence of pertinent parameters, including Sisko fluid parameters, concentration of nanotubes, stretching sheet velocity, and porous medium characteristics on the flow, heat, and mass transfer profiles. From the graphs and statistical analysis, it is clear that the volume fraction of SWCNT and MWCNTs are strongly correlated. The investigation reveals that increasing the inclination angle affects the fluid velocity. The variation in all flow features is negligible for volume fractions of CNTs between 0% and 10% but a significant effect is observed only beyond 10%. Higher volume fractions of CNTs result in enhanced local heat transfer coefficient. This can be attributed due to the outstanding heat transfer capabilities of CNTs owing to their high thermal conductivity. However, Shear thickening fluids exhibit high heat transfer phenomena when compared to shear‐thinning and Newtonian fluids. This research provides valuable insights into the optimization of CNT‐based nanofluids for efficient heat and mass transfer applications in electronics cooling, heat exchangers, and solar energy systems, offering opportunities to enhance energy efficiency and device performance.

An Experimental Investigation on Synthesis, Characterization, and Photothermal Conversion Efficiency of Stable Aqueous Nanofluids Containing Multiwalled Carbon Nanotubes for Direct Absorption Solar Collectors

The nanofluids are the potential substitute in solar collectors as working fluids for better photothermal conversion efficiency. The present investigation focuses on the development of aqueous‐based nanofluids comprising multiwalled carbon nanotubes (MWCNTs) with and without surfactants to enhance the capacity of photothermal conversion in direct absorption solar collectors. To improve the stability of the nanofluid, the gum Arabic (GA) and polyvinyl alcohol (PVA) are used as the surfactants. The stable nanofluid was characterized using UV‐visible spectroscopy, zeta potential, fourier‐transform infrared spectroscopy, field emission scanning electron microscopy, and energy dispersive X‐ray spectroscopy (EDS) analysis. The results indicated that the thermal conductivity was enhanced by 94.57% and 91.19% for the MWCNT/GA/deionized (DI) water and MWCNTs/PVA/DI water based nanofluids in presence of surfactants at 90 °C and 0.02 wt%. The presence of surfactant in MWCNTs/DI water nanofluids exhibit excellent stability and enhanced MWCNTs dispersion. In the photothermal response analysis, the highest temperature of 62.8 °C, which is 16 °C higher than the base fluid, is obtained from 0.02wt% MWCNT/GA nanofluid. The highest efficiency of 27.94% is recorded when 0.02wt% MWCNT/GA nanofluid is used, which shows 71.24% enhancement as compared to the DI water after exposure of 30 minutes under solar irradiation. The use of MWCNTs/GA nanofluid as light‐absorbing working fluids in solar collectors is encouraged in the present investigation.

Artificial neural network (ANN) approach in predicting the thermo-solutal transport rate from multiple heated chips within an enclosure filled with hybrid nanocoolant

This study focuses on enhancing heat and mass transfer in an electronic cooling system such as a rectangular cavity that contains equidistant heated chips along the bottom wall. The cavity of the present study is filled with ethylene glycol (30:70) based hybrid nano coolants of different volume fractions (ϕ) of Multi-walled Carbon Nanotube (MWCNT), Aluminum Oxide (Al2O3), and Copper Oxide (CuO). The set of equations controlling the thermo-solutal natural convection within the enclosure is simulated using the Galerkin weighted residual finite element method (FEM). The study has shown a good agreement of numerical results with different experimental reports within the framework of the present study. A solution space is constructed based on governing parameters such as Rayleigh number, buoyancy ratio, and Lewis number. A hybrid nano-coolant containing ϕMWCNT = 1.5 %, ϕCuO = 0.5 %, and ϕAl2O3 = 2 % showed a 3.11% improvement in heat transfer rate compared to the base fluid, highlighting its potential for thermal management applications. This study also investigates various machine learning models for predicting the heat and mass transfer rate, and an error analysis is conducted on the K-Nearest Neighbour Regressor, Random Forest Regressor, Decision Tree Regressor, and ANN model. The ANN model with 6-50-100-50-2 architecture showcases the best fit with the mean squared error of 0.8923 and an R² value of 99.96 % on testing data. The ANN model exhibits its capability to predict heat transfer and mass transfer rates within the error ranges from 1–2 % and 2–3 %, respectively, even at a strong thermal buoyancy force (Ra = 10⁵). This accuracy showcases a novel use of ANN to efficiently predict thermo-fluidic transport behaviors of hybrid nanofluids, offering a faster alternative to resource-intensive simulations. The present study opens new possibilities for real-time, cost-effective cooling solutions, particularly in microelectronics and renewable energy, while maintaining high prediction accuracy by integrating machine learning with the nanotechnology approach.

Optimizing Aqueous Zinc-Sulfur Battery Performance via Regulating Acetonitrile Co-Solvents and Carbon Nanotube Carriers.

Rechargeable aqueous zinc-sulfur batteries (AZSBs) are gaining attention due to their high energy density, ultra-stable discharge platform, and safety. However, poor liquid/solid reaction processes at the anode and cathode reduce reaction kinetics, and the severe dissolution of polysulfides causes shuttle effects during discharge/charge cycles, hindering practical applications. Improving performance requires optimizing both the cathode and electrolyte. Herein, we design an organic-inorganic hybrid electrolyte (zinc trifluoromethanesulfonate and trace iodine monomer dissolved in an acetonitrile/water co-solvent (AN-X)) and a partially exfoliated multi-walled carbon nanotube (PECNT) hosted sulfur (S@PECNTs) cathode for AZSBs. The sulfur is highly dispersed along the PECNTs with appropriate wettability at the electrode/electrolyte interface using AN-3 as the electrolyte. Meanwhile, this electrolyte inhibits hydrogen evolution at negative potentials and promotes uniform Zn ion stripping/plating. Expressively, the AN-3-based AZSB exhibits a high discharge capacity of 1370 mAh g-1 with excellent Coulombic efficiency (79.9%), outstanding rate capability, and cycling performance. These improvements are attributed to the synergistic effect between the S@PECNTs and the AN-3 electrolyte, which reduces Rct to enhance reaction kinetics and blocks the dissolution and shuttle effect of polysulfides, ensuring a reversible reaction between zinc and sulfur.

Facile synthesis of active sites-rich magnetic adsorbent by simple one-pot hydrothermal strategy for quick and highly capable capture of female-steroid hormones

Rapid and efficient extraction is highly desired in the accurate quantification of female-steroid hormones (FSHs) in complex samples. In this context, an active sites-rich magnetic adsorbent (MAC) modified with carboxylated multiwalled carbon nanotubes and 4-vinylphenylboronic acid was facilely synthesized through one-pot hydrothermal technique for the magnetic solid phase extraction (MSPE) of FSHs in water and urine samples. Various characterizations revealed that the prepared adsorbent contained abundant functional groups, acceptable magnetic properties, high surface area and good stability. Due to the multiple interactions, the developed MAC/MSPE exhibited high isolation and preconcentration capability towards studied FSHs within 10 min. The concentration factors were 151–354 and the adsorption capacity was as high as 3.2 mg/g. Adsorption behaviors of MAC/MSPE towards FSHs were studied based on adsorption kinetics and isotherm experiments. After optimizing the extraction parameters, the MAC/MSPE was combined with HPLC to sensitive and reliable monitoring of studied FSHs in various waters and female urine samples. The limits of detection and recoveries with different spiked contents were 0.0015–0.0026 μg/L and 80.1–119 %, respectively. Accuracy of the established method was evaluated by confirmatory testing. Moreover, sample preparation greenness of the developed method was assessed. The present study uncovered the prospect of MAC/MSPE in the rapid and highly capable capture of FSHs, and also supplied a sensitive and reliable approach for the monitoring of trace FSHs in complex samples.

Photocatalytic degradation of ampicillin antibiotics in aqueous solution utilizing ZnFe2O4/MWCNTs/TiO2 ternary nanocomposite under solar light irradiation

In this study, a novel photocatalyst composed of zinc ferrite (ZnFe₂O₄), titanium dioxide (TiO₂), and multi-walled carbon nanotubes (MWCNTs) was successfully synthesized via the hydrothermal method, and evaluated for the degradation of ampicillin (AMP) in aqueous solutions. The synthesized nanocomposites were thoroughly characterized using various analytical techniques, including XRD, HR-SEM, HR-TEM, EDX, UV-Vis, FT-IR, BET, and XPS analysis. Crystallite sizes of 24.18 nm for ZnFe₂O₄ and 17.8 nm for TiO₂ were determined. The composite exhibited a band gap of 1.4 eV, indicating its enhanced photocatalytic activity. The photocatalytic performance was assessed under varying conditions, including different nanocomposite dosages (0.3–1 g/L), AMP concentrations (10–50 mg/L), and pH values (2–12). The optimal AMP degradation efficiency of 99.2 % was achieved using 0.7 g/L of the photocatalyst, 10 mg/L of AMP, and a pH of 12 under 90 min of solar irradiation. These optimal parameters were then applied to evaluate AMP degradation using ZnFe2O4, TiO2, and ZnFe2O4/MWCNTs individually, with the degradation rate analyzed using a pseudo-first-order model. The superior photocatalytic efficiency can be primarily attributed to improved charge transfer dynamics and effective electron-hole separation, enabled by the doping of MWCNTs. Hydroxyl radicals (OH•) were identified as the primary reactive species responsible for AMP degradation. Furthermore, the catalyst retained 91 % of its photocatalytic efficiency after eight consecutive cycles, demonstrating excellent stability and reusability. These results underscore the potential of the ZnFe₂O₄/MWCNTs/TiO₂ composite as a highly effective and sustainable photocatalyst for removing pharmaceutical pollutants from aquatic environments.

Solid-Phase Microextraction Mediated Solid-Phase Dielectric Barrier Discharge Vapor Generation-Atomic Fluorescence Spectrometry for Sensitive Determination of Mercury in Seawater.

A novel method coupling solid-phase microextraction (SPME) to solid-phase dielectric barrier discharge (SPDBD) vapor generation was proposed and used for the sensitive detection of trace mercury (Hg) in seawater with atomic fluorescence spectrometry (AFS) in this work. The method proposed herein offers the unique advantages of integrating desorption and chemical vapor generation into one step, eliminating the use of elution reagents, and reducing the analysis time. SPME with multiwalled carbon nanotubes (MWCNTs) coated on the glass tube was used to extract Hg2+ in seawater. The Hg2+ was then desorbed and reduced to Hg0 vapor by SPDBD, which was detected by cold vapor AFS. The parameters affecting Hg2+ extraction, desorption, and vapor generation were studied. The detection limit of Hg2+ was 0.0003 μg L-1, and the relative standard deviation at a Hg2+ concentration of 0.05 μg L-1 was 4.4%. This method also has excellent antimatrix interference ability for Hg2+ determination with recoveries between 91.8% and 101.1% in the presence of extremely high concentrations (two million times excess) of coexisting ions. The practicality of this method was also evaluated by analyzing two different certified reference materials of Hg2+ in water and several seawater samples with good spike recoveries (94.0%-107.4%). Compared with solid-phase photothermo-induced vapor generation, this method has higher extraction efficiency and higher desorption efficiency without the assistance of heating as well as a lower detection limit of Hg2+, which is capable of performing trace Hg analysis in seawater.

Study on the electromagnetic wave absorption performance of dual-loss type composite MWCNT/CIP/GF/EP

Abstract The electromagnetic properties of single-loss glass fiber (GF) absorbing composites with the addition of multi-walled carbon nanotube (MWCNT) particles and single-loss glass fiber (GF) absorbing composites with the addition of carbonyl iron powder (CIP) particles in the X-band were studied. Using CST electromagnetic simulation combined with experiments, dual-loss multi-walled carbon nanotube/carbonyl iron powder/glass fiber/epoxy (MWCNT/CIP/GF/EP) resin absorbing composites were designed and prepared. The effects of thickness ratio and periodic layering on the absorbing properties of dual-loss glass fiber absorbing composites were investigated. The results show that by changing the thickness ratio and periodic layering, the impedance matching and attenuation characteristics of the dual-loss glass fiber absorbing composites can be altered, thereby affecting the overall absorbing performance. The optimal group exhibited a maximum reflection loss of -55.3 dB at 8.5 GHz, with an effective absorption bandwidth of 3.0 GHz, covering 71.4% of the X-band.

Effect of carbon nanotube incorporation on the mechanical and physical properties of hydroxyapatite/glass ionomer nanocomposite

This manuscript discusses the potential use of multi-walled (MW) carbon nanotubes (CNTs) as a filler material in hydroxyapatite/glass ionomer cement HA/GIC nanocomposite to enhance its properties: mechanical and physical. Four different proportions (1, 2, 3, and 5 wt%) of CNTs were added to the HA/GIC nanocomposite to determine the optimum ratio that can lead to the best properties of the new nanocomposite biomaterial. Mechanical mixing technique followed in dentistry was used in preparing all samples. FTIR, PSA, XRD, TEM, and SEM were used to characterize the fabricated Pellets. In addition, the new nanocomposite samples were evaluated using compressive and diametral tensile tests. Overall, increasing the weight ratio of CNTs added to the nanocomposite (from 1 to 5 wt%) caused about a 40% reduction in the compression strength of the samples. However, a slight increase (about 4%) was detected at 2 wt% CNTs samples. Also, a distinct increase in the elasticity of the composite (about 50%) was reported. The best results of diametral tensile strength were found at a 3 wt% CNTs. Furthermore, for all samples, adding CNTs to the composite changed the sample’s color from A2 and B2 to totally black color.

Enhancement of mechanical and tribological properties in glass fiber-reinforced polymer composites with multi-walled carbon nanotubes and ANN-based COF prediction

ABSTRACT The study investigated the effects of incorporating multi-walled carbon nanotubes (MWCNTs) into glass fiber-reinforced polymer composites on their mechanical and tribological properties. Experimental results demonstrated significant enhancements across various parameters. Microhardness increased by 25.03%, attributed to improved interfacial bonding and load transfer facilitated by MWCNTs. Tensile strength and modulus improved by 10.58% and 28.2%, respectively, indicating reinforced load-bearing capacity. Flexural strength and modulus increased by 33.78% and 36.29%, respectively, due to enhanced interfacial bonding. Inter-laminar shear strength (ILSS) exhibited a notable increase of 20.79% with MWCNT incorporation. Ity mpact toughness improved by 19.41% in Izod and 32.32% in Charpy tests, attributed to MWCNTs’ energy-dissipating properties and enhanced interfacial bonding. Tribological tests showed decreased wear and friction coefficients, along with reduced debris formation and fiber breakage in SEM analysis, indicating improved bonding between the matrix and fibers. Furthermore, an artificial neural network (ANN) model accurately predicted the coefficient of friction, aligning well with experimental values, offering potential for predictive modeling in composite material analysis. Overall, the incorporation of MWCNTs significantly enhanced mechanical properties and wear resistance of the composite material.