Dispersion Of Carbon Nanotubes Research Articles

A comparative study of mixing nano particles in the bitumen by dry and wet method

Pavement deterioration owing to rutting, fatigue, and stripping provides substantial issues, needing early rehabilitation to avoid accidents and delays. Given the high costs of pavement repair and reconstruction, the use of additives to extend pavement life emerges as an economically viable approach. While previous initiatives have used admixtures such crumb rubber, cement, and geosynthetics to improve asphalt binder qualities, this research focuses on improving stripping, rutting, fatigue resistance, and viscosity by incorporating carbon nanotubes (CNTs). Methanol was used as a solvent in the present research to ensure uniform dispersion of CNTs, resolving a recurring issue. Mixing was ensured effectively by using a high-shear mixer that functioned for 40–45 minutes at 300–4800 rpm. To figure out how CNTs affected the performance of asphalt binder, various ratios of 0.3%, 0.6%, 0.9%, and 1.2% were investigated. The use of carbon black nanoparticles (CBNPs), graphene nanoparticles (GNPs), and multiwalled carbon nanotubes (MWCNTs) as bitumen modifiers shows potential for improving the quality of asphalt binder. MWCNTs' excellent tensile strength and heat resistance make them ideal for transportation engineering applications. However, challenges exist in CNT preparation, economic implications, and attaining homogenous dispersion in bitumen. The investigation involves the creation of nine modified bitumen samples utilizing both wet and dry mixing procedures. The findings demonstrate that GNPs have a significant potential to improve bitumen stiffness properties. Furthermore, a higher percentage of nanocomposite resulted in reduced penetration, softening point, and ductility values, enhancing bitumen stiffness and resistance to rutting. Despite promising results, challenges regarding CNT preparation, cost-effectiveness, and uniform dispersion in bitumen indicate the need for additional research and development in this area.

Development of an Electron Emitter via Seamless Shaping of a 3D‐Printed Ceramic Cone With Carbon Nanotube Mesh Film as an Alternative to Polymer‐Based Materials

AbstractThis paper focuses on electron emitters formed using seamless hybrid shaping of the ceramic 3D‐printed cone (as a supporting structure) and a conductive emitting film obtained from the suspension of dispersed carbon nanotubes (CNT). The ceramic cone is post‐process fired to achieve a pure ceramic cone that is coated with emitting CNT mesh film. Meanwhile, a cone‐based polymer emitter is evaluated. The resulting emitter exhibits non‐linear current‐voltage characteristics reaching maximum 0.6 mA anode current with a turn‐on‐field voltage below 1 Vµm−1 and minimal current fluctuation over time. Additionally, the ceramic emitter arrays fabricated using the same technique are demonstrated: if the tip angle and shape in a microscale have tunability in emission is confirmed, meanwhile, the type of volatile gases released during the emission is confirmed using a residual gas analyzer (RGA). The motivation and challenge are to use 3D printing to enable freedom in designing and forming the emitter tip shape and angle and to present the perspective and challenges to use the 3D printing technique combined with the seamless shaping for the CNT mesh film to tune the emitter performance. Especially as this technique and 3D‐printed materials have not been previously employed for electron emitters.

A solar-powered electrocoagulation process with a novel CNT/silver nanowire coated basalt fabric cathode for effective oil/water separation: From fundamentals to application.

Electrocoagulation (EC) has proven its high efficiency and environmental sustainability for treating several types of wastewaters. However, the primary drawbacks of the conventional EC process are the suitable electrode materials and the relatively high cost due to the requirement for electric energy. To overcome these practical challenges, this study investigated effective oil/water separation by a solar-powered electrocoagulation (SPEC) process using a novel highly conductive basalt fabric (BF) cathode. The BF cathode was fabricated using a simple approach: dip-coating in carbon nanotubes (CNT) dispersion, followed by a bath exhaustion coating in a silver nanowires (AgNws) solution, and its successful preparation was confirmed through several advanced characterization techniques. The effect of the CNT-AgNws coating on the electrical conductivity of the BF-CNT/AgNws was investigated using the four-probe tester. The BF-CNT/AgNws cathode exhibited a high conductivity of 1.66×104S/m, which indicates its applicability in the SPEC system. Under the operating conditions of applied voltage (25V), SPEC time (30min), stirring rate (150rpm), and NaCl concentration (1g/L), the experiment's results showed a high COD removal of 90.2±0.03 %, a low energy consumption of 1.28±0.01 kWh/kgCOD, and electrode consumption of 0.35±0.06kg/m3. In addition, due to the use of solar-powered energy, the overall cost was reduced by eliminating the electricity fees. Moreover, the reusability test results proved that the BF cathode has potential reusability in successive SPEC experiments while maintaining its performance. In conclusion, the obtained findings are very encouraging in designing novel EC cathodes for effective oily wastewater treatment at an industrial scale.

Binary and Ternary Nanocomposite Membranes for Gas Separation Incorporating Finely Dispersed Carbon Nanotubes in a Polyether Block Amide Matrix

This work addressed the fine dispersion of Multiwalled Carbon Nanotubes (MWCNTs) in a polymer matrix to obtain Mixed Matrix Membranes (MMMs) suited for gas separation. Not-purified MWCNTs were effectively loaded within a polyether block amide (Pebax®2533) matrix, up to 24 wt%, using ultrasonication as well as a third component (polysorbate) in the dope solution. The obtained flexible thin films were investigated in terms of morphology, thermal properties, characterized by SEM, FT-IR, DSC, TGA, and gas permeation tests. The response to temperature variations of gas permeation through these nanocomposite specimens was also investigated in the temperature range of 25–55 °C. Defect-free samples were successfully obtained even at a significantly high loading of CNTs (up to 18 wt%), without a pre-treatment of the fillers. A remarkable enhancement of gas permeability upon the nanocarbons loading was reached, with a threshold value at a loading of ca. 7 wt%. The addition of polysorbates in the ternary MMMs further improves the dispersion of the filler, enhancing also the permselectivity of the membrane.

Thermally conductive polymer foams with sodium-dodecyl-benzenesulfonate-surface-modified graphene nanoplatelets and carbon nanotubes: supercritical CO2-induced foaming

Lightweight composite foams with high thermal conductivities are difficult to obtain owing to the trade-off between thermal conductivity and porosity. In this study, to improve the dispersion of graphene nanoplatelets (GNP) and multi-walled carbon nanotubes (MWNT) and the uniformity of pore size, sodium dodecyl benzenesulfonate (SDBS) can be used, which acts as a surface modification agent on GNP and MWNT and as a foam stabilizer on supercritical carbon dioxide (scCO2) foaming. The mixed morphology composite (MMC) network leads to improved thermal conductivity, which is not significantly reduced after scCO2 foaming. This may be attributed to the fact that the SDBS-assisted MMC networks of GNP and MWNT in polyamide 6 (PA6) are maintained after foaming with the homogeneous pores by scCO2 and the SDBS stabilizer. Thus, the density of the composite decreases to 1.249g/cm3 after foaming. The resulting high-heat-dissipation composites possess lightweight properties and high thermal conductivities, which are promising for application as battery pack components in next-generation automobiles.

The chemical functionalization advantages of carbon nano heli-coil reinforcements for multifunctional polymeric nanocomposites

Carbon nanotubes (CNTs) have demonstrated superior mechanical, electrical, and thermal properties. Our previous studies have shown that the Heli-coil CNTs (HCNTs) perform better than the straight CNTs as nanoscale reinforcements, primarily due to their heli-coil structural configurations that can additionally provide mechanical-interlocking-mechanisms between the microfibers and resin. Pristine CNTs are inert and do not disperse well in polymers and form weak bonds with resin molecules. One of the techniques to improve the dispersion of CNTs and their bonding effectiveness is to chemically functionalize them. In this research, HCNTs that were covalently functionalized using a mixture of nitric, sulfuric, and hydrochloric acids following 16 different procedures, varying the process parameters (i.e., sonication time, acid molarity, and mixing sequence) were used. The pristine and functionalized HCNTs (FHCNTs) were incorporated into epoxy resin at very low weight percentages (i.e., 0.02, 0.04, and 0.06 wt%), processed, used to fabricate nanocomposite test specimens, and then tested according to ASTM standards. The main objective of this research was to investigate the effects of chemical functionalization process parameters and wt% of FHCNTs on the mechanical performance of polymeric nanocomposites. The test results showed improvements of up to 5.7%, 35.1%, 11.1%, 49.5%, and 60% for the tensile strength, fracture toughness, modulus, strain-to-failure, and hardness, respectively, that were mostly related to 0.02 wt% of FHCNTs reinforcements for the functionalization procedures 2, 4, and 10. Additionally, the fractured specimens were inspected and analyzed using 3D scanning-laser-confocal-microscopy and SEM imaging, and the most effective functionalization processes were recommended for structural nanocomposite applications.

Ternary Epoxy Nanocomposites with Synergistic Effects: Preparation, Properties Evaluation and Structure Analysis.

The objective of the present work was to prepare hybrid epoxy composites with improved mechanical and thermal properties. The simultaneous use of two different modifiers in an epoxy resin was motivated by the expected occurrence of synergistic effects on the performance properties of the matrix. Such a hybrid composite can be used in more severe conditions and/or in broader application areas. Hybrid epoxy composites were prepared with polyurethane (PUR), Nanomer nanoclay and carbon nanotubes (CNT), followed by the evaluation of their mechanical and thermal properties. Synergistic improvements in mechanical properties of hybrid composites were observed for 0.5 wt% Nanomer and 1 wt% carbon nanotubes (CNT), 7.5 wt% PUR and 1 wt% CNT, and 5 wt% PUR and 1 wt% CNT, confirming the occurrence of synergistic effects as to the impact strength (IS) of the matrices, compared to binary systems. The toughening induced by CNT/Nanomer modifiers can be attributed to the specific interfacial interactions between the two nanoparticles, while in the case of CNT/PUR, it can be explained by the combined effects of flexible polymer chains and the specific arrangement of nanoparticles in epoxy systems. Spectroscopy analysis confirmed the occurrence of interaction between OH groups in the epoxy matrix with CNT and reactive groups of PUR. The fracture surface showed plastic deformations, with good dispersion of CNT, explaining the improved mechanical properties of the matrix composites.

Eco-Friendly Fabrication of NCM811 Cathodes with Alcohol-Based Dispersion of Single-Walled Carbon Nanotubes for Lithium-Ion Battery Application

Eco-Friendly Fabrication of NCM811 Cathodes with Alcohol-Based Dispersion of Single-Walled Carbon Nanotubes for Lithium-Ion Battery Application

Study of the Dispersion, Working, and Mechanical Properties of Carbon Nanotubes in Ultrahigh-Performance Concrete

Study of the Dispersion, Working, and Mechanical Properties of Carbon Nanotubes in Ultrahigh-Performance Concrete

Poly(lactide)/poly(butylene adipate-co-terephthalate)/carbon nanotubes composites with robust mechanical properties, fatigue-resistance and dielectric properties.

A styrene-glycidylmethacrylate-1-allyl-3-vinylimidazole epoxy functionalized ionomer (EFI) was synthesized, and the EFI and carbon nanotubes (CNTs) were co-introduced into poly(lactide)/poly(butylene-adipate-co-terephtalate) (PLA/PBAT) blends to fabricate high performance composites with excellent mechanical properties, fatigue-resistance and dielectric properties. It is revealed that EFI can improve the interaction force between PLA and PBAT by inducing the interfacial crosslink reaction, thereby improving the melt strength of the samples. EFI can also refine the dispersion of CNT in the composites owing to the non-covalent force between EFI and CNT, promote the formation of filler network inside composites, which is demonstrated by DMA and rheological test results. The CNT can be anchored at the interface between PLA and PBAT owing to the interaction between EFI and CNT, and the synergistic effect of CNT and EFI on the interfacial structure and phase structure can significantly enhance the mechanical properties of the materials. When the CNT content is 3 wt%, the composite has a tensile strength of 30.4 MPa and an elongation at break of 279.3 %, which are 30 % and 48 % higher than that of PLA/PBAT blend, and it also exhibits excellent dielectric properties with a dielectric constant of 25.2 and a dielectric loss of 11.6. Moreover, the composites also have excellent fatigue resistance owing to the refined interfacial structure and compact CNT network.

Optimization of CNT-carbon fabric composites for enhanced mechanical and thermal properties, and improved fracture toughness: Finite element simulation and experimental validation

An optimal dispersion of chemically functionalized Multi-Walled Carbon Nanotubes (CNTs) in Carbon Fiber Reinforced Polymer Composites (CFC) can enhance mechanical and thermal properties. Nano-composite fabrication involves precise processing steps and parameters supported by simulations to explain deformation and fracture mechanisms. Controlled dispersion and processing reveal a significant interplay between stiffening and strengthening in the CNT-matrix. Crack bridging optimizes nano-scale stiffening and strengthening by delaying micro-crack initiation and propagation, emphasizing the importance of CNT dispersion and entanglement disruption. The correlation between nano-scale stress, fracture energy, and optimal CNT spacing at the macro-fiber interface is critical. With dilute CNT dispersion, improvements of 8% in specific modulus and strength in the matrix lead to significant enhancements in the fabric system, mainly through CNT-fiber interfacial mechanisms. This optimization results in a 9%–13% increase in specific stiffness, a 5%–9% increase in specific strength, and improved fracture properties. Thermal stability improves with increased storage modulus, glass transition temperature, and thermal conductivity (18%–25%), while specific heat capacity increases by 30% with 0.3 wt % CNT in the composite. CNT nano-reinforcement enhances fracture toughness, transferring to the fabric-matrix interface with a transfer ratio greater than one. CNT-modified carbon fabric composites demonstrate the highest interlaminar fracture properties, with a Mode-II to Mode-I fracture toughness ratio greater than 9, compared to the base composite. These studies establish a normalization scheme for nano-composite design and evaluation, providing insights for developing damage-tolerant, lightweight, and durable structural designs through multi-objective optimization.

Sustainable nanomaterials: the role of Cyrene in optimising carbon nanotubes dispersion and filtration efficiency

Sustainable nanomaterials: the role of Cyrene in optimising carbon nanotubes dispersion and filtration efficiency

Sequential Admicellar Polymerization of Polyindole and Poly(vinyl Acetate) for Increasing Electrical Conductivity and Water Dispersion of Multiwalled Carbon Nanotubes

Sequential Admicellar Polymerization of Polyindole and Poly(vinyl Acetate) for Increasing Electrical Conductivity and Water Dispersion of Multiwalled Carbon Nanotubes

Stretchable thermoplastic polyurethane/single-walled carbon nanotube masterbatch nanocomposites with enhanced electrical conductivity and thermal properties

A thermoplastic polyurethane (TPU)/single-walled carbon nanotube (SWCNT) nanocomposite was developed using a twin-screw extrusion process followed by injection molding. This study aimed to enhance the properties of TPU by incorporating a SWCNT masterbatch, with a polyol ester serving as the carrier resin. The electrical conductivity, rheological behavior, mechanical performance, and thermal properties of the TPU/SWCNT nanocomposites were systematically evaluated. The incorporation of the SWCNT masterbatch significantly improved the electrical conductivity of the TPU nanocomposites. With SWCNT loading levels below 0.6 wt%, the viscosity and processability of the nanocomposites were maintained. However, a noticeable decrease in viscosity was observed when the SWCNT content exceeded 0.6 wt%. The tensile and storage modulus of the nanocomposites increased, attributed to the stiffness and reinforcing effects of SWCNTs. Despite a slight reduction in tensile strength and elongation at break upon SWCNT addition, the tensile properties of the TPU/SWCNT nanocomposites at a loading of 0.4 wt% remained well-suited for strain sensor applications. The polyol ester in the SWCNT masterbatch facilitated the uniform dispersion of carbon nanotubes within the TPU matrix and enhanced the nucleation ability of SWCNTs, contributing to improved performance characteristics.

Impact of similarity transformations on hybrid nanofluid thermal behavior with thermal radiation on nonlinear stretching surface via Hermite wavelet transformations

An investigation into a non-linearly stretching surface was conducted, focusing on a unique combination known as a shape-dependent hybrid nanofluid. The nanofluid consisted of a mixture of ethylene glycol and water, with dispersed multi-walled carbon nanotubes (MWCNT) and silver (Ag) particles of various shapes, including spherical, columnar, and lamellar. Many fluid flow problems require the use of similarity transformations to simplify the problem. However, it is crucial to derive an appropriate set of similarity transformations for each specific flow problem. Unfortunately, many researchers have overlooked this step or used inappropriate similarity transformations borrowed from other works, leading to erroneous results. This paper aimed to address this issue by deriving the correct set of similarity transformations for a specific flow problem, ensuring that the similarity variable was dimensionless and dependent on all independent variables in the formulation. Additionally, the stretching velocity was appropriately dimensioned. The semi-analytical solution for the modified differential equations was obtained using the Hermite wavelet transformation method, while the numerical solution for the coupled differential equations was solved using the 4th – 5th order Runge–Kutta-Felhberg method. A 64.5% increase in the Prandtl number leads to a 53.49% decrease in temperature. An 800% increase in the radiation parameter results in a 105.76% rise in temperature. Additionally, a 100% increase in the Eckert number causes the temperature to increase by 71.82%. This work emphasizes the importance of deriving appropriate similarity transformations for specific flow problems.

Enhancing Heat Transfer Efficiency Through Controlled Magnetic Flux in a Partially Heated Circular Cavity Using Multi-Walled Carbon Nanotube Nanofluid and an Internal Square Body

Applications including aircraft systems and electronics cooling depend on effective heat transfer. This study investigates magnetohydrodynamic (MHD) free convection and thermal radiation for heat transfer in a circular cavity filled with multi-walled carbon nanotube (MWCNT) nanofluid and containing a square obstruction. This study examines the impact of the internal geometry on heat transfer and fluid flow dynamics under three distinct boundary conditions, and it presents a comprehensive analysis based on a wide range of Hartmann (Ha) and Rayleigh (Ra) numbers. MWCNT nanofluid with high thermal conductivity was employed to enhance heat transfer efficiency, using a solid volume fraction (SVF) of 4% for MWCNTs and assuming Newtonian behavior for computational simplification. Magnetic properties were imparted to the nanofluid by assuming the dispersion of carbon nanotubes in a base fluid containing magnetic nanoparticles. Other walls were insulated, the bottom wall was heated, and a magnetic field (MF) with Ha ranging from 0 to 100 was applied. It was observed that raising Ra from 103 to 106 improved the Nusselt number (Nu) from 0.08 to 7.1 using the Galerkin finite element method. Ha increased from 0 to 100 and reduced Nu by 35%. Three boundary conditions for the square body showed that the heated conditions provided the largest Nu. By means of an increase in SVF from 0 to 0.04, the MWCNT nanofluid improved heat conductivity by 18%. Radiation effects with the radiation parameter Rd = 0.5 increased heat transmission by 22%. These results underline the importance of considering MHD and nanofluid characteristics in maximizing heat transfer for commercial purposes, and the approaches employed in this study contribute to a deeper understanding of the behavior of thermal systems under the influence of MHD and internal geometry.

Fundamental Thermodynamic Aspects for the Effective Dispersion of Carbon Nanotubes and Improve Performance Grade of Bitumen

The application of carbon nanotubes to enhance bitumen properties is relevant due to the need to increase the durability of asphalt concrete pavements and reduce maintenance costs. Key areas requiring further study include the processes during ultrasonic dispersion, the selection of the optimal medium, and the stability of the resulting dispersions. This study examines dispersions containing multi-walled carbon nanotubes (MWCNTs) Taunit M (from 5·10−4 to 5·10−2%) and various hydrocarbon plasticizers. For the first time, the change in Gibbs free energy, enthalpy (interaction energy), and mixing and disordering entropy was calculated based on experimental data (surface tension, average cubic diameter of MWCNTs, molecular mass, etc.). The data were compared with the storage stability of polymer-modified binders (PMBs). It was found that mixing entropy plays a key role in forming thermodynamically stable dispersions, while the contribution of disordering entropy is minimal. High dispersion enthalpy of MWCNTs can reduce dispersion stability at high concentrations despite entropy growth. Systems with selective purification extracts showed the best PMB stability despite thermodynamic instability. The property changes after 3 days at 180 °C were no more than 5%. This suggests structural changes from component interactions are critical, highlighting the need for an integrated approach considering both thermodynamic and macroscopic properties.

PH-responsive re-dispersible dispersions of carbon black and single-walled carbon nanotubes in arabinogalactan solutions

pH-responsive re-dispersible dispersions of carbon black and single-walled carbon nanotubes in arabinogalactan solutions

Ethylene glycol-mediated dispersion enhancement of oxidized MWCNTs for improved electrochemical performance in flexible, free-standing OCNT/LMO electrode

The rapid advancement of flexible electronics and wearables necessitates high-capacity flexible batteries that adapt to various shapes and movements. Carbon nanotubes (CNTs), with their exceptional electrical conductivity, mechanical flexibility, and structural stability, are promising candidates. However, achieving a well-dispersed and uniform distribution of CNTs and heavy active materials like lithium manganese oxide (LMO) particles in different matrices is challenging due to issues with agglomeration and quick sedimentation. This study uses ethylene glycol (EG) as a dispersing solvent to form strong hydrogen bonds with oxidized CNTs, enhancing dispersion stability and preventing re-aggregation. Its higher viscosity compared to water helps in better stabilizing and dispersing LMO particles within the oxidized CNT suspension by reducing sedimentation. The OCNT/LMO-EG electrode shows a higher discharge capacity of 128 mAh/g with Coulombic efficiency of 99.6% after 200 cycles, compared to the OCNT/LMO-W2 electrode, which uses water for dispersion and achieves 108 mAh/g with 99.6% efficiency. These results highlight ethylene glycol's potential to improve CNT and LMO dispersion, resulting in a homogeneous electrode structure with enhanced conductivity and higher capacity.

In-situ grown carbon nanotubes on waste glass powder: resource-efficient preparation and machine-learning based dispersion evaluation

Carbon nanotubes (CNTs) are the strongest candidates as reinforcing and functionalizing materials in civil engineering. However, CNTs have severely limited the application of carbon nanomaterials in civil engineering materials because of high-cost preparation and inhomogeneous dispersion. In this paper, a new method of direct in-situ grown CNTs on the surface of waste glass powder (WGP) by microwave pyrolysis is employed. It can control the particle size and growth of CNTs while effectively improving the CNTs dispersion and saving natural resources. The dispersibility of in-situ grown CNTs and MWCNT in aqueous and cement pore solutions is evaluated based on DLS and improved machine learning and image processing methods. The conductivity as well as the compressive strength of the electrically conductive cementitious materials increases linearly with increasing dispersion. This work facilitates further optimization of CNT-cement nanocomposite dispersion and has great potential for improving WGP utilization efficiency.