Search Results (2,187)

This review comparatively analyzed MWCNT-reinforced thermoplastic polyester nanocomposites based on petroleum-derived (PET, PBT) and bio-based (PLA, PBS) matrices, focusing on processing methods, mechanical performance, thermal stability, electrical behavior, and recyclability. Optimal MWCNT loadings typically ranged from 0.3 to 3 wt.%; higher loadings induced nanotube agglomeration and deteriorated properties due to poor dispersion and stress concentration. Melt mixing, solution blending, direct compounding, and in situ polymerization were evaluated, and their influence on dispersion quality, interfacial bonding, and scalable manufacturability was discussed. PET exhibited the largest improvements in mechanical and thermal performance (tensile strength and modulus increases >300% in optimized systems); acid or compatibilizer functionalization of MWCNT improved PET thermal stability by approximately 20–50 °C and promoted heterogeneous nucleation. PBT reached optimal reinforcement at 0.3–1 wt.% MWCNT, yielding tensile strength increases up to ~57% alongside increased crystallinity and faster crystallization kinetics. PLA generally showed reduced tensile strength after MWCNT addition unless compatibilized (e.g., via plasticizers or grafting), whereas PBS consistently gained strength, modulus, and crystallinity but experienced reductions in ductility. Electrical percolation thresholds varied widely (0.25–14 wt.%), demonstrating that dispersion quality, nanotube functionalization, and processing route governed conductivity and percolation behavior more than matrix chemistry. Recyclability and circular economy aspects were assessed: while PET/MWCNT systems showed promise for mechanical recycling and property recovery, data on repeated reprocessing, CNT structural integrity, and long-term electrical performance were scarce; PBT recycling studies were limited, and PBS/PLA recycling with retained conductive networks remained underexplored. Based on the comparative analysis, key limitations, critical research gaps, and practical recommendations for processing, compatibilization, and end-of-life evaluation were identified to guide future work aimed at enhancing both performance and sustainability of polyester/MWCNT nanocomposites. Full article

Lithium-ion batteries are widely used in digital, power and energy storage fields due to their high capacity and high cycle life advantages. This paper systematically screens the formulation system and designs a high-efficiency production line that can effectively improve production efficiency, reduce production costs, and lower energy consumption per unit product. The produced nano-silicon-enhanced graphite anode material has excellent performance. The selection of silicon raw materials, types of solvents, types of dispersants, and grinding processes is studied to investigate the influence of these four factors on the wet grinding process for preparing nano-silicon. Finally, metal silicon obtained by air flow pulverization is selected as the raw material, isopropanol is used as the solvent, FA01 (carboxylic acid type) is used as the dispersant, and a two-stage wet grinding process is adopted to prepare the nano-silicon dispersion solution. Zirconia beads of 0.5 mm and 0.2 mm size are used as the grinding media for the first and second stages, respectively, with filling rates of 80% and 90%, respectively. The final prepared nano-silicon dispersion is stable in dispersion and has a narrow particle size distribution. The nano-silicon dispersion solution and the multi-walled carbon nanotube dispersion solution are mechanically ground and mixed using a sand mill. At the same time, the multi-walled carbon nanotubes are coated with the nano-silicon. Then, artificial graphite is added for compounding. Finally, through spray drying, the Si@MWCNTs@graphite (SMG) nano-silicon-enhanced graphite negative electrode material is prepared. The SMG nano-silicon-enhanced graphite negative electrode material with a silicon content of 2% has a first Coulomb efficiency of up to 84.32%. Full article

Multiwalled carbon nanotubes (MWCNTs) and nanoalumina (nano-Al₂O₃) have each been studied separately in asphalt binders, but whether their combined thermal gain translates into microwave-induced healing at the mixture scale remains unestablished. This study aimed to evaluate, through a multiscale approach, their combined incorporation into a polymeric asphalt binder modified with 4% styrene-butadiene-styrene (SBS), focusing on mechanical performance and microwave-induced healing. Binders with 0 to 6% hybrid nanomaterial (50:50) were characterized structurally, chemically, rheologically, and thermally, and mixtures were evaluated for rutting, four-point bending fatigue, and microwave heating and healing. A content of 2.3% was selected from rheological and thermal criteria. At this content, the mixture heating rate rose from 0.18 to 0.41 °C/s (127.8%) and rut depth decreased by 22.1%. The nanomodified binder reduced the top-to-bottom Jnr_3.2 gradient from over 250% to 56–59%, indicating improved storage compatibility rather than complete stability. Fatigue life at 250 μm/m decreased by 53.7%. Despite this, healing increased by 9.6% in dynamic modulus recovery and 61.9% in fatigue healing index. Overall, hybrid nanomodification improved resistance to permanent deformation and microwave-induced healing, clarifying their combined effect, although the fatigue penalty requires further investigation. Full article

In this work, composites based on thermosetting polymers (epoxy, polyester and vinylester resins) are presented, in which carbon particles and cenospheres are embedded. The influence of combinations of multi-walled carbon nanotubes (MWCNTs) and cenospheres, as well as amorphous carbon and cenospheres, on the mechanical properties and electromagnetic attenuation in (part of) the X-band range (812 GHz) of the developed composites has been studied. It has been established that the used combinations of carbon particles and cenospheres have the greatest positive effect on the mechanical properties of the composites based on vinylester resin. The developed materials demonstrate effectiveness for electromagnetic protection in the X-band range. The combination of a polymer matrix and appropriate fillers leads to significant attenuation of the radio frequency signal. The presented composites are suitable materials for integration into various defense systems—from coatings to structural elements with functional purposes. Full article

Environmental impacts of wastewater from textile and dyestuff industries are of growing concern due to limited freshwater availability and inadequate treatment facilities. Carbon nanotubes (CNTs) offer excellent adsorption potential because of their outstanding mechanical and chemical properties, however; their application in textile effluent treatment has not been widely studied. Moreover, laboratory-based studies are often costly and limited to a few variables, making it challenging to reveal the underlying relationships among several physicochemical parameters and CNT treatments. Multivariate statistical analysis (MVSA) offers an effective approach to overcome this challenge. To the best of our knowledge, no studies have integrated laboratory analysis of nanotube-based textile effluent treatment with an MVSA approach. This study aims to evaluate the physicochemical characterization of textile effluent, treat effluent with CNT, and explore the relationship between physicochemical parameters and CNT by integrating laboratory experiments with MVSA. For this purpose, single-walled CNT (SWCNT) and multi-walled CNT (MWCNT) were applied in batch mode adsorption experiments using various dosages and adsorption times. Scanning electron microscopy and Fourier transform infrared spectroscopy (FTIR), along with physicochemical analyses, were conducted to characterize the effluent and adsorption processes. The FTIR spectrum indicated that the absorption peaks of C=C, C=O, and the acidic f -OH group on CNTs enhance wettability and hydrophilic character, thereby increasing adsorption capacity. Experimental results demonstrated significant reductions in electrical conductivity (EC), total dissolved solids (TDS), turbidity, total organic carbon (TOC), and chemical oxygen demand (COD). CNT dosages of 1 to 5 g/100 mL and adsorption times of 2 to 5 h achieved removal efficiencies ranging from approximately 20% to 90% for SWCNT and MWCNT. MVSA indicated that MWCNT was more strongly associated with ionic and physical parameters (turbidity, TDS, EC, and pH), whereas SWCNT was more strongly related to organic load indicators, particularly COD and TOC. Overall, this study highlights the potential of CNT coupled with the MVSA technique as an effective and sustainable approach for textile wastewater treatment and offers valuable insights for researchers working in this field. Full article

The integration of carbon nanomaterials with organic compounds offers a promising strategy for developing next-generation electrode materials with superior properties. A novel type of carbon paste electrode was fabricated by modifying a graphite matrix with functionalized multiwalled carbon nanotubes and juglone as a redox mediator, and then it was deposited by manual packing into a PEEK body (JUG-MWCNT/CPE). The surface morphology and structural parameters of the composite materials were meticulously characterized using scanning electron microscopy (SEM), nitrogen adsorption–desorption isotherms, and spectroscopic techniques, while their electrochemical properties were rigorously evaluated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). This study demonstrates that the synergistic interaction between the conductive nanotube network and the electroactive juglone significantly reduces the oxidation overpotential and enhances the peak current response of melatonin. Under optimized DPV parameters, the developed sensor presents outstanding analytical performance, featuring a wide linear response range from 0.002 to 0.16 mg L⁻¹, a low detection limit of 0.49 µg L⁻¹, excellent long-term signal stability for up to 30 days, and valid applicability for real-sample monitoring in commercial tablets and dietary supplements. Full article

Cement slurry is a staple grouting agent, yet its properties can weaken when exposed to heat. Studying grouting materials for use in high-temperature tunnels is therefore a matter of considerable importance. To enhance the applicability of cement-based slurry in high-temperature tunnels, multi-walled carbon nanotubes (MWCNTs), polycarboxylate ether superplasticizer (PCE), and hydroxypropyl methylcellulose (HPMC) were added to improve their performance at elevated temperatures. Various experimental methods were employed to investigate the properties of the modified slurry at different temperatures, including flowability, setting time, compressive strength, and dynamic water retention ratio. Additionally, X-ray diffraction (XRD), thermogravimetric analysis (TG), and scanning electron microscopy (SEM) were used to study the effects of temperature on hardened slurry. Experimental results indicate that the optimal MWCNTs content is 0.32%. At this content, the compressive strength of the hardened slurry after 28 days of curing at 80 °C increases by approximately 20%, reaching 26.4 MPa. PCE improves the fluidity of the slurry, while HPMC enhances its water dynamic water retention ratio. The optimal proportion was found to be 0.3% PCE and 0.2% HPMC. At this ratio, the fluidity of the slurry increased by about 8%, reaching approximately 17.7 cm; the dynamic water retention ratios of 0.8 m/s and 1.0 m/s improved by approximately 22% and 38%, respectively, achieving 35.8% and 18.1%. Furthermore, multi-walled carbon nanotubes significantly enhance the compressive strength of the hardened slurry primarily by suppressing the formation of ettringite during the later stages of hydration, as well as by providing nucleation sites, encapsulating hydration products, and bridging hydration product clusters within the microstructure. This investigation lays a theoretical groundwork for formulating and choosing grouting materials suited to high-temperature tunnel environments. Full article

In polymer selective laser sintering (SLS), powder acts as a support material during additive manufacturing, generating significant amounts of un-sintered powder exposed to prolonged thermal cycles. Although partial reuse with virgin powder is common practice, material degradation eventually renders the powder unsuitable for further SLS processing. This study investigates a sustainable approach for valorising SLS waste powder through its conversion into filament feedstock for fused filament fabrication (FFF). Polyamide 12 filaments containing 0, 2, 3, and 4 wt.% multi-walled carbon nanotubes (MWCNTs) were produced by twin-screw extrusion to tailor the electrical conductivity of the polymer matrix. The filaments were processed by FFF to manufacture specimens for thermal, mechanical, and electrical characterization. Differential scanning calorimetry revealed the influence of reprocessing on the thermal behaviour of the reused material and resulting filaments, while thermogravimetric analysis demonstrated improved thermal stability with increasing MWCNT content. Tensile testing showed increased Young’s modulus (up to 9.4%), despite an initial drop, and tensile stress at break (up to 56.3%) with increasing nanofiller concentration. In addition, distinct electrostatic-discharge (ESD) protection ranges were achieved depending on the MWCNT loading. The results demonstrate the potential of reused SLS powder as a sustainable feedstock for functional AM materials suitable for ESD-sensitive applications. Full article

Composite materials based on humic acids and multi-walled carbon nanotubes were synthesized using ultrasonic-enhanced co-precipitation. The effect of ultrasonic treatment duration on the structure and adsorption properties of the composite materials with respect to phenol was studied. The structural and functional characteristics of the materials were investigated using elemental analysis, FTIR spectroscopy, SEM, TGA/DTA, and determination of the content of oxygen-containing functional groups. It was found that the Σ(COOH+OH) values for the studied composites are in the range of 3.00–4.45 mmol/g. The highest value of this indicator was observed for the HA:MWCNTs-20 (US = 30 min) composite. The results of physicochemical studies show that the ultrasonic treatment duration has a significant effect on the morphological, functional, and thermal characteristics of the composites. Adsorption properties were studied in the phenol concentration range of 0.5–15 mg/dm³. It was shown that the HA:MWCNTs-20 (US = 30 min) composite exhibited the highest adsorption capacity for phenol among the studied samples. Analysis of adsorption isotherms revealed that the experimental data were most satisfactorily described by the Langmuir model (r = 0.996–0.999), while the kinetic data were best described by the pseudo-second-order model. These results demonstrate the potential of HA:MWCNTs composites as sorption materials for extracting phenol from aqueous solutions. Full article

Hybrid conductive materials have attracted increasing attention due to their combined electrical conductivity, mechanical flexibility, and sustainability. In this work, new hybrid materials based on polyaniline (PANI)-wrapped multi-walled carbon nanotubes (MWCNTs) and microfibrous cellulosic substrates were developed and assessed for photocatalytic degradation of a model dye pollutant. First, in situ oxidative polymerization of aniline in formic acid (FA) was conducted in the presence of MWCNTs to afford stable dispersions of carboxylated polyaniline-wrapped carbon nanotubes (c-PANI/MWCNTs). Next, the dispersions were used for affordable impregnation of microfibrous cellulosic filter paper. The influence of the initiator type—potassium peroxodisulfate (KPS) and hydrogen peroxide—on polymer–nanotube interactions, stabilization and surface deposition was emphasized. The structural, surface, morphological and thermal properties of the obtained dispersions and cellulose nanocomposites were systematically investigated using Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and thermal gravimetric analysis. The results revealed strong interfacial interactions between c-PANI and the pristine MWCNTs, resulting in improved dispersion stability and effective and even surface deposition of the conductive c-PANI/MWCNT hybrids into the cellulose fiber mesh. The photocatalytic degradation of 5 ppm methylene blue (MB) dye in the presence of the developed nanocomposite materials under UV-A illumination was studied. The results showed that the c-PANI@MWCNT-impregnated cellulose substrates exhibited enhanced photocatalytic ability (up to 83% degree of degradation of MB dye) in comparison with the pure c-PANI. Full article

Polyethylene (PE) fibers are promising reinforcements for engineered cementitious composites (ECC); however, their highly hydrophobic nature and inherent chemical inertness limit their reinforcing effectiveness. This study investigated the use of different types of multi-walled carbon nanotubes (MWCNTs) to modify PE fibers under varying immersion times. Microstructural characterizations were conducted to investigate the effects of MWCNTs type and immersion time on the surface properties of PE fibers, while mechanical testing was undertaken to evaluate the mechanical performance of the resulting fiber-reinforced cementitious composites. MWCNTs were found to form a uniform coating on the surface of the reinforced PE fibers, resulting in a reduction in water contact angle from 164.2° to 118.4° and an increase in oxygen contents by 242.27%. With increasing immersion time, the single-fiber pull-out strength improved by up to 40.48%, with an optimal modification duration of 8 h. The MWCNTs modified PE fibers were found to increase the 28-day uniaxial tensile strength and three-point bending strength of the cementitious composites by up to 16.17% and 6.96%, respectively, while exhibiting negligible effects on compressive strength. This study implies that MWCNTs can effectively enhance surface wettability and mitigate surface inertness of PE fibers, thereby enhancing the overall performance of ECC. Full article

Enhancing the mechanical performance of aluminium-based materials remains a critical challenge for their application in demanding environments. In this context, aluminium-based hybrid nanocomposites reinforced with multi-walled carbon nanotubes (MWCNTs) and nano-sized silicon carbide (nSiC) have been developed to overcome inherent limitations of pure aluminium, such as relatively low hardness, limited compressive strength and poor wear resistance. The composites were fabricated via powder metallurgy by incorporating a fixed 1 wt.% MWCNT content along with varying nSiC additions in the range of 0–4 wt.%, enabling a systematic evaluation of the effect of hybrid reinforcement on the overall material properties. Compared to pure aluminium, the composites exhibited significant improvements in mechanical and tribological properties, with the Al–1 wt.% MWCNT–4 wt.% nSiC composition showing the highest enhancement, achieving increases of ~149% in hardness and ~45% in compressive strength. Microstructural analysis revealed strong matrix–reinforcement bonding, notable grain refinement, and a largely uniform reinforcement distribution, with minor agglomeration at higher nSiC content. The hybrid nanocomposites also demonstrated superior wear resistance, while fractography indicated a transition from ductile fracture in pure aluminium to a mixed intergranular–transgranular mode, promoting effective load transfer and improved performance. Full article

This study aims to develop sustainable conductive nanocomposites based on poly(lactic acid) (PLA)/poly(ε-caprolactone) (PCL) blends reinforced with multi-walled carbon nanotubes (MWCNT) and graphene nanoplatelets (G), focusing on their multifunctional performance. The novelty lies in the production of hybrid nanocomposites based on PLA/PCL blends with MWCNT/G using conventional industrial processing techniques, enabling the development of eco-friendly nanocomposites with tailored electrical, mechanical, and electromagnetic properties. The nanocomposites were prepared by twin-screw extrusion followed by injection molding. Rheological, scanning electron microscopy (SEM), mechanical, thermal, thermomechanical, electrical conductivity, and electromagnetic shielding properties were systematically evaluated. From a rheological perspective, the PLA/PCL/MWCNT and PLA/PCL/MWCNT/G nanocomposites exhibited a plateau at low frequencies, associated with the formation of a percolated network. This was confirmed by the significant increase in electrical conductivity and electromagnetic shielding response. The morphology observed by SEM showed a refinement of the PCL phase in the PLA matrix with the incorporation of MWCNT. The PLA/PCL/MWCNT/G (4/2 parts per hundred resin, phr) nanocomposite showed a 309% increase in impact strength compared to neat PLA, while maintaining the heat deflection temperature (HDT). The elastic modulus exceeded 2300 MPa and accelerated the crystallization process by more than 15 °C compared to PLA, which makes it important to reduce injection molding time. Additionally, it exhibited the highest electrical conductivity level, around 6.79 × 10⁻⁵ S/cm, which resulted in improved electromagnetic shielding performance in the 8.2–18 GHz range, highlighting the synergistic effect between 1D and 2D fillers. The developed PLA/PCL/MWCNT and PLA/PCL/MWCNT/G nanocomposites demonstrate potential for antistatic applications, combining sustainability with multifunctional performance and industrial scalability. Full article

The use of hydrolytic enzymes is one of the most promising methods for combating bacterial biofilms. However, the use of native enzymes is limited by the rapid loss of activity under unfavorable conditions. Immobilization of enzymes on carbon nanoparticles enhances their stability, allows for biocatalyst reuse, and creates a synergistic effect due to the intrinsic antimicrobial properties of the nanomaterials. The aim of this investigation was to create and comparatively analyze conjugates of acid and alkaline proteases with carboxylated multiwalled carbon nanotubes (MWCNTs-COOH) and to assess their effect on the formation and destruction of E. coli VKM B-3858D biofilms. The immobilization efficiency and kinetics of enzyme adsorption on the support were quantified by determining the protein concentration using the Bradford assay. The morphology and dispersion of the resulting conjugates were analyzed using atomic force microscopy (AFM). Protease activity was determined by a modified Anson method using the Folin–Ciocalteu reagent. Biofilm biomass was determined using crystal violet staining. The binding efficiency of the acid protease to MWCNTs-COOH was shown to reach 93%, which is significantly higher than that of the alkaline protease. The highest degree of immobilization was observed at a protein concentration of 117–338 μg/mL (10–20 mg/mL of the enzyme preparations). The interaction of the acid protease with the carbon nanoparticles increased dispersion, reducing the size of aggregates from ~1 μm to ~68 nm. As a result, acid protease conjugates with MWCNTs-COOH significantly reduced the biofilm biomass compared to both the enzyme-free control and the native enzyme. Alkaline protease, unlike the acid protease, destroys mature biofilms, and immobilization on MWCNTs-COOH enhances this ability. Native alkaline protease and acid protease conjugates with MWCNTs-COOH are effective in combating the biofilm formation of Gram-negative bacteria, while alkaline protease conjugates are suitable for disrupting mature biofilms. Full article

Carbon nanotubes (CNT) are among the strongest candidates for electromagnetic interference (EMI) shielding materials because of their excellent performance. However, when assembled into macroscale materials, their conductivity is usually limited to 10⁴ S/m, restricting further application as shielding materials. Here, we prepared a carbon nanotube composite film (Au/Cl-CNT) with high conductivity and excellent EMI properties. Characterizations confirm that Au exists in the form of uniform Au plates and particles anchored on the CNT surface, while Cl is doped into the CNT framework as halogen dopants. The optimized Au/Cl-CNT film delivers an ultra-high electrical conductivity of 3.39 × 10⁵ S/m, which is approximately 23 times higher than that of the pristine CNT film. The excellent electrical properties of the Au/Cl-CNT films endow them with excellent EMI shielding effectiveness (SE). Au/Cl-CNT films with a thickness of ~10.5 μm achieve an EMI SE of up to 67 dB across both the X-band and Ku-band. The superior EMI SE mainly results from the combined effect of various mechanisms, namely reflection inside and outside the material, as well as absorption inside the material. This work clarifies the synergistic enhancement mechanism of Au and Cl on CNT conductivity and EMI shielding, offering new insights into halogen-modified shielding materials. Full article