Introducing Carbon Nanotubes Research Articles

Production of carbon nanotubes as composite material modifiers using nanotechnology

Modern trends in composite materials science are associated with nanotubes having a carbon framework structure. The aim of this article is to develop and produce new composite materials using nanoparticles with increased characteristics, including radiation absorption with the possibility of their use in design schemes of various kinds of industry. The structure of nanotubes is determined by synthesis methods. Moreover, the CNTs characteristics are determined by the methods of transmission microscopy. In particular, the analysis of the profile of the X-ray spectral lines was carried out using a mixed Gaussian-Lorentzian distribution function. The multilayer CNTs were obtained by the method of catalytic decomposition of propylene. As a result, the improvement of physical and mechanical characteristics by 30–40% is achieved. Thus, the efficiency of introducing carbon nanotubes into the polymer matrix to improve the physicochemical, physical-mechanical, and operational characteristics of composite nano-polymer materials is proved. Finally, it is shown that functionalized carbon-containing nanoparticles could be used as modifiers to regulate the process of curing and elastification of epoxy substances when creating polymer composite materials for structural purposes.

Blends of polydimethylsiloxane-based polyurethane and poly (propylene glycol)-based polyurethane with co-continuous structures: Morphology evolution, synergistic effects and application in strain sensors

Blending is an effective way to improve properties of rubbers and develop new materials, so more than 75 % of the rubber consumption in the world is rubber blend. However, blending of thermoplastic elastomers has not yet been emphasized, and few successful examples have been reported. The main challenge for blend systems is compatibility of two components. Herein, a series of (polydimethylsiloxane-based PU)-g-(poly (propylene glycol)-based PU) ((PDMS-PU)-g-(PPG-PU)) graft copolymers with different graft chain lengths and hard segment contents (HSC) were synthesized and utilized as compatibilizers of PDMS-PU/PPG-PU blends. The influence of the structure of compatibilizers on the morphology of blends was investigated, and the compatibilization mechanism was proposed. With the solubilization, the phase structure of blends transforms from “droplet-in-matrix” morphologies to co-continuous ones, and the average size of PPG-PU dispersed phase decreases from 3.5 ± 0.45 μm to 230 ± 60 nm. This is the first time that thermoplastic PDMS-PU/PPG-PU blends with co-continuous structures have been successfully prepared. The properties of blends exhibit synergistic effects. For example, they show high tensile strength of PPG-PU in mechanical properties and unique properties of PDMS in dynamic mechanical properties, weather resistance, water resistance and biocompatibility. In addition, strain sensors were fabricated by introducing carbon nanotubes (CNTs) into the blends, which demonstrated remarkable sensing capability for diverse human body motions.

Method for introducing carbon nanotubes into fine-grained concrete

This work discusses the use of a modifying complex additive to concrete with the inclusion of carbon nanotubes “Taunit-M” and the SP-3 plasticizer. Two methods of introducing nano-sized additives into the composition of fine-grained concrete, as well as their combination, are considered. The results of a series of tests of beam samples aged 28 days are presented using two methods of introducing nanotubes, namely: the use of an ultrasonic dispersant and the use of a linear induction rotator (LIR). The positive effect of introducing nanotubes on the strength characteristics of concrete has been established. It has been determined that the use of LIR technology provides an increase in strength due to a double effect: activation of the cement binder and distribution of the nanoadditive using active mixing due to vortex action. Ultrasonic dispersion, in turn, ensures the effective introduction of the plasticizer into the mixing water.

Influence of Carbon Nanotubes in Improving the Superconducting and Structural Properties of Bulk Bi-2212 Synthesis by Thermal Treatment Method

Bi-2212 superconductor has garnered significant interest in recent years due to its potential applications in the development of superconducting wires and tapes. The effect of introducing carbon nanotubes (CNT) into the Bi-2212 system was investigated in terms of superconducting and structural properties. The results of this study indicated that the addition of CNTs had a notable effect on the phase formation of Bi-2212, with a substantial increase from 86.8% to 97.4% for the sample with a weight percentage of 0.8 wt.%. This can be attributed to the improved particle orientation brought about by the introduction of CNTs. The microstructure analysis displayed randomly distributed grains of irregular shapes, with a reduced average grain size of 1.018 μm upon the addition of 0.4 wt.% CNTs. Additionally, the inclusion of CNTs led to an increase in the Tc value, with the maximum Tc-onset recorded at 79 K for the sample containing 0.6 wt.% CNTs. In summary CNT has enhanced the structural and the superconducting properties of the Bi-2212 synthesised with thermal treatment method.

Synthesis of carbon nanotube aerogels from cross-linked polyacrylamide/chitosan hydrogels via gamma irradiation for efficient oil removal

Environmental pollution, stemming from oil spills and improper disposal of organic solvents, severely threatens global water resources and ecosystems. This study addresses this concern by introducing carbon nanotube (CNT) aerogels as efficient adsorbents for removing pump oil and various organic solvents from water. Aerogels were synthesized from cross-linked Chitosan/polyacrylamide hydrogels using gamma irradiation in the presence of sodium silicate, incorporating varying concentrations of CNTs (1 %, 2 %, and 3 %). Characterization techniques, including FTIR, SEM, EDX, BET surface area analysis, and compression testing, unveiled the structural and physicochemical properties of the aerogels. Incorporation of CNTs substantially enhanced surface area and compressive strength, with the CNT 3 % aerogel exhibiting remarkable values (316 m2/g and 8.677 MPa, respectively). Hydrophobicity was confirmed by water contact angles (89° to 94°). The CNT aerogels demonstrated outstanding oil removal efficiency, reaching 93.15 %, surpassing the blank aerogel (38.01 %). The CNT aerogel achieved 80.68 % efficiency for methanol removal compared to 62.09 % for the blank aerogel. Kinetic studies revealed a chemisorption process, emphasizing the enhanced chemical interactions facilitated by CNTs. These findings underscore the promising potential of CNT aerogels for effectively removing oil and organic solvent contaminants from water, even at low concentrations.

Carbon nanotubes anchored SiOx composite anode for high cyclic stability lithium-ion batteries

Silicon suboxide (SiOx, 0 < x < 2) is one of the most promising anode materials because of its high lithium-ion storage capacity. However, the poor intrinsic conductivity and large volume change during cycling limits its practical application as lithium-ion battery anode materials. Herein, we propose a novel strategy to introduce carbon nanotubes (CNTs) on the SiOx particles, forming a conductive network and relieving the volume expansion effect, which possess improved reversible capacity and robust structure for long cycling stability. The SiOx/CNT composite anode delivers reversible capacity of 1533.8 mAh g−1 at the first cycle and maintains 599.6 mAh g−1 after 500 cycles with a high coulombic efficiency of 99.7 %. In this paper, SiOx composite anchored by CNTs was prepared, which is a simple and effective strategy to improve the conductivity of SiOx, relieve the volume effect and further promote its electrochemical performance benefit from the high conductivity and structural stability of CNTs. This research provides a significant reference for constructing the delicate structure of SiOx-based composites to enhance cyclic performance.

Modified electron structure of CNT-CoSe2 (vs. CoSe2) with more Co2+ for improving catalytic effect in lithium sulfur batteries

Currently, the great challenge of lithium sulfur (Li-S) batteries is the sluggish redox kinetics and the ineludible shuttle effect, which induce the rapid capacity fading. Regulating the electron structure of metal-based catalysts is regarded as a significant strategy to improve the catalytic effect of Li-S batteries, for accelerating the redox kinetics and enhancing the cathode performance. In this work, the valence of Co in CoSe2 is regulated by introducing carbon nanotube (CNT) during the preparation of ZIF-67. Compared with CoSe2, the ratio of Co2+/Co3+ increases, which boost the catalytic activity of CNT-CoSe2 both in discharging and charging process. Furthermore, the ratio of Co2+/Co3+ is reduced after discharging due to the electron transfer to sulfur species, and the ratio is increased again due to the inverse electron transfer. As a result, the CNT-CoSe2 with better catalytic properties endows the corresponding Li-S batteries more stable cycling performance, especially at high current density or high sulfur loading. The CNT-CoSe2 modified separator can endow Li-S batteries with a discharge capacity of 735.49 mAh g−1 at 2 C, and a retention ratio of 72.28% for 200 cycles at 0.1 C with sulfur loading of 4.60 mg cm−2.

Tunable fabric zinc-based batteries utilizing core-shell like fiber electrodes with enhanced deformation durability

One-dimensional (1D) fiber-based batteries stand as a promising route for next-generation wearable devices, owing to their combined energy storage capability and wearability. However, the development of efficient fiber electrodes and high-quality battery configurations that retain excellent electrochemical performance and garment compatibility while withstanding variable mechanical deformations remains a pressing challenge. In this study, NiCo2S4@rGO nanocomposites with stable structures and excellent electrochemical performance were constructed using an in-situ hydrothermal strategy. The highly conductive network of reduced graphene oxide (rGO) improved the electron transport efficiency of the nanocomposites, while mitigating volume changes, structural collapse, and self-aggregation of NiCo2S4 nanoparticles during the charging/discharging cycle. As expected, the nanocomposite cathodes in the Zn-based batteries exhibited remarkable discharging capacity (277.11 mAh g−1) and cycling performance (70% retention after 2000 cycles). Subsequently, a composite fiber cathode (NiCo2S4@rGO-PU-CNTs) with tailorable length and core-shell like structure was fabricated via wet spinning. Benefiting from the introduced carbon nanotubes (CNTs) and polyurethane (PU), the composite fiber cathode formed efficient dual-conducting networks and stable core-shell like structures, thereby improving the electron transport pathways and mechanical flexibility. Finally, as a proof of concept, the independent NiCo2S4@rGO-PU-CNTs cathode and independent Zn@SSY (stainless steel yarn) anode were woven into a knitted fabric, creating tunable serpentine footprint fabric Zn-based batteries with exceptional electrochemical properties (175.29 mAh g−1 and 0.088 mAh cm−1), coupled with remarkable electrochemical stability and mechanical deformation durability. The engineering strategy reported herein provides a promising platform for the quick, facile, and continuous preparation of composite fiber cathodes and tailorable wearable energy textiles.

Bioinspired Hollow/Hollow Architecture with Flourishing Dielectric Properties for Efficient Electromagnetic Energy Reclamation Device.

The exploitation of advanced electromagnetic functional devices is perceived as the effective prescription to deal with environmental contamination and energy deficiency. From the perspective of observing and imitating nature, pine branch-like zirconium dioxide/cobalt nanotubes@nitrogen-doped carbon nanotubes are synthesized victoriously through maneuverable electrospinning process and follow-up thermal treatments. In particular, introducing carbon nanotubes on the surface of hollow nanofibers to construct hierarchical architecture vastly promoted the material's dielectric properties by significantly augmenting specific surface area, generating abundant heterogeneous interfaces, and inducing the formation of defects. Supplemented by the synergistic effect between each constituent, ultra-strong attenuation capacity and perfect impedance matching characteristics are implemented simultaneously, and jointly made contributions to the splendid microwave absorption performance with a minimum reflection loss of -67.9dB at 1.5mm. Moreover, this fibrous absorber also exhibited promising potential to be utilized as a green and efficient electromagnetic interference shielding material when the filler loading is enhanced. Therefore, this design philosophy is destined to inspire the future development of energy conversion and storage devices, and provide theoretical direction for the creation of sophisticated electromagnetic functional materials.

Facile synthesis of MAPbI3/CNTs composites with superior electromagnetic wave absorption performances

Perovskite shines as a top contender in the realm of electromagnetic waves (EMW) absorption, owing to its unique physical properties, structural characteristics, and multifunctionality. However, it is still a huge challenge to synthesize high-performance EMW absorbing perovskite materials with environmental-friendly and sustainable processes, despite the simplicity of the perovskite preparation procedures. To address this issue, a facile solvent-free method was developed in this study for CH3NH3PbI3 (MAPbI3), then introduced carbon nanotubes (CNTs) and subsequently prepared MAPbI3/CNTs (MC) composites using a simple procedure. The frequency, thickness, reflection loss (RL), and effective absorption bandwidth (EAB) of MC for EMW absorption were systematically investigated by adjusting the filling amount and component ratio of MC. It is interesting to find that the as-prepared MC composites always achieve high absorption intensities in X and Ku bands. Moreover, an appropriate amount of CNTs can further optimize the impedance matching of MC and promote the loss capability of MAPbI3.With a loading ratio of 25 wt% and a mass ratio of 2:1 between MAPbI3 and CNTs, the MC sample exhibits excellent absorption capability, achieving the lowest RL of −63.8 dB at 1.8 mm and the maximum EAB of 5.16 GHz at 1.69 mm. These findings contribute to the design and development of organic-inorganic halide perovskite absorbers with superior EMW absorption performances.

In-situ growth of LiFePO4 with interconnected pores supported on carbon nanotubes via tavorite-olivine phase transition

Lithium iron phosphate (LiFePO4) has gained significant attention as a promising cathode material for lithium-ion batteries due to its excellent stability and safety characteristics. However, its relatively low electrical conductivity restricts its practical application in high-power devices. In this study, we propose a novel approach to improve the electrochemical performance of LiFePO4 cathodes by introducing carbon nanotubes (CNT) through an in-situ growth process. Firstly, CNT serve as nucleation sites for the growth of FePO4, which subsequently attaches and grows in situ on CNT, resulting in the precipitation of CNT/FePO4. Subsequently, pre-lithiation is performed to synthesize CNT/LiFePO4OH, which ensures efficient mass transfer and uniform reaction achieved by wet chemical lithiation process. Eventually,The improved lattice perfection of CNT/LiFePO4 is obtained through the tavorite-olivine phase transition at a low crystallization temperature, allowing for more favorable ion diffusion pathways. Furthermore, in conjunction with the uniform incorporation of CNT to enhance the overall conductivity of the composite, the presence of intrinsically interwoven pores entwined amidst a bedrock of LFP nanoparticles is unveiled. These intricately connected pores function as conduits, promoting the seamless diffusion of electrolyte across the composite structure. This, in turn, augments the interfacial engagement between the cathode and electrolyte, propelling a surge in electrochemical reactivity and harnessing a heightened level of electrochemical efficacy, thereby amplifying the overall electrochemical performance and efficiency. Electrochemical tests demonstrate that the CNT/LiFePO4 cathodes exhibit significantly prominent rate capability with 143.0 mAh g-1 at a rate of 20C, and remarkable cycling stability with a retention rate of ∼97.0% under 1000 cycles at 1C. The in-situ growth of CNT/LiFePO4 offers a simple and scalable approach for the modification of LiFePO4 cathodes, enabling the practical utilization of this promising material in high-performance lithium-ion batteries.

Fluorinated graphene and CNT-based surface plasmon resonance sensor for detecting the viral particles of SARS-CoV-2

Due to the ability to distinguish between infected and uninfected individuals, the continuing highly contagious Coronavirus disease pandemic, which is brought on by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), highlights the vital role that diagnostic testing plays in outbreak containment. The COVID-19 virus must be detected using timely, accurate, and economical procedures. One such method for doing this is optical sensors, particularly surface plasmon resonance (SPR), which has benefits like high sensitivity and great detection limits. The SPR sensor for the detection of viral particles of COVID-19 that we suggest in this study is based on a basic Kretschmann configuration. The performance factors for this structure were determined using MATLAB numerical analysis based on angle interrogation. Introducing Carbon nanotubes and Fluorinated graphene enhances the sensitivity of the suggested SPR sensor to 400°/RIU for one layer of fluorinated graphene and five layers of carbon nanotubes. Furthermore, utilizing COMSOL Multiphysics, the electric field improvement shown for different layers used in our suggested structure is addressed.

Sterical Self-Consistency of Carbonaceous Nanopolyhedra Triggered by Introduced CNTs to Optimize ORR Performance

The electrocatalyst of oxygen reduction reactions is one of the basic components of a fuel cell. In addition to costly Pt/C benchmark catalysts, cost-effective carbon-based catalysts have received the most attention. Enormous efforts have been dedicated to trade off the catalyst performance against the economic benefit. Optimizing composition and/or structure is a universal strategy for improving performance, but it is typically limited by tedious synthesis steps. Herein, we have found that directly introducing CNT into MOF-derived carbonaceous nanopolyhedra, i.e., introduced carbon nanotubes (CNTs) penetrated porous nitrogen-doped carbon polyhedra (NCP) dotted with cobalt nanoparticles (denoted as CNTs-Co@NCP), can optimize the catalytic activity, stability, and methanol tolerance. The hierarchical architecture combines the 0D/1D/3D Co/CNT/NCP interfaces and 1D/3D CNT/NCP junctions with the frameworks with a greatly exposed active surface, strengthened mass transport kinetics, stereoscopic electrical conductivity networks and structural robustness. The sterical self-consistency of MOF-self-assembly triggered by introduced CNTs demonstrates tactful ORR electrocatalytic activity regulation. Eventually, the CNTs-Co@NCP showed a half-wave potential (E1/2) of 0.86 V and a diffusion-limited current density (JL) of 5.94 mA/cm2 in alkaline electrolyte. The CNTs-Co@NCP was integrated into the cathode of a direct methanol fuel cell (DMFC) with an anion-exchange membrane, and an open-circuit voltage (OCV) of 0.93 V and a high power density of 46.6 mW cm−2 were achieved. This work successfully developed a catalyst with competitive ORR performance through plain parameter fine-tuning without complex material design.

Hollow multi-shelled spherical Co3O4/CNTs composite as a superior anode material for lithium-ion batteries

Hollow multi-shelled spherical Co3O4/CNTs composite was prepared by a facile MOF-assisted strategy by introducing carbon nanotubes (CNTs) directly into the precursor. The hierarchical porous structure of the obtained multi-shelled Co3O4 nanospheres can effectively alleviate volume change and facilitate the infiltration of electrolyte into the interior. The interconnected CNTs can reduce the electrochemical polarization by improving the conductivity of the body material. As an anode for lithium ion batteries, the as-synthesized Co3O4/CNTs composite exhibits superior lithium ion storage performance. A high reversible specific capacity of 653.1 mAh g−1 was obtained after 500 cycles at 1000 mA g−1, suggesting a significant inspiration for fabricating application for advanced electrochemical devices.

Enhanced interlaminar fracture toughness of CF/PEEK laminates by interleaving CNT-decorated PEEK films

The weak interlaminar properties severely hinder the high-property applications of carbon fiber (CF) reinforced thermoplastic composites. Here, interlaminar properties were significantly enhanced by introducing carbon nanotube (CNT) decorated polyether ether ketone (PEEK) films into the interlayer. PEEK films decorated with different CNT contents were fabricated by the spraying and thermoforming processes. Tensile test results show that the films with a CNT surface density of 45 mg/m2 exhibit superior tensile strength and Young's modulus due to the higher crystallinity and larger crystalline size. The introduction of this modified film into unidirectional CF reinforced PEEK laminates leads to an increase by 101% to 1.67 kJ/m2 in interlaminar fracture toughness, while the interlaminar shear strength is retained. Fractographic analysis reveals that the increase in interlayer resin content and crack path deflection are primary factors contributing to interlaminar toughening. Molecular dynamics simulation demonstrates that incorporating CNT in the interlayer resin significantly improved the interfacial bonding strength between fiber and resin, thus resulting in crack path deflection.

Surface sizing introducing carbon nanotubes for interfacial bond strengthening of basalt fiber–reinforced polymer composites

Surface sizing introducing carbon nanotubes for interfacial bond strengthening of basalt fiber–reinforced polymer composites

Hierarchical and Porous Structures of Carbon Nanotubes-Anchored MOF Derivatives Bridged by Carbon Nanocoils as Lightweight and Broadband Microwave Absorbers.

High-performance microwave absorption (MA) materials have attracted more and more attention because they can effectively prevent microwave radiation and interference from electronic devices. Herein, a new type of MA composite is constructed by introducing carbon nanotubes (CNTs)-anchored metal-organic framework derivatives (MOFDs) into a conductive carbonnanocoil (CNC) network, denoted as CNC/CNT-MOFD. The CNC/MOFD shows a wide effective absorption band of 6.7GHz under a filling ratio of only 9% in wax-matrix. This is attributed to the hierarchical and porous structures of MOFD bridged by the uniformly dispersed conductive CNC network and the cross-polarization induced by the 3D spiral CNCs. Besides, the as-grown 1D CNTs improve space utilization, porosity, and polarization loss of the composites, resulting in the increase of imaginary permittivity, which further realizes impedance matching and energy attenuation. The Ni nanoparticles in layers of MOFD and at the tips of CNTs generate magnetic loss, promoting the low-frequency absorption ability. Resultantly, RCS values of the optimized composite in all tested theta (θ) ranges are less than -25dB m2 at 9.5GHz, effectively reducing the probability of the target detected by the radar.

Influence of MXene and carbon nanotube on the mechanical properties of sisal fibre/glass fibre reinforced epoxy composite laminates

The present experimental work investigates the influence of E-glass fiber hybridization on the tensile and bending characteristics of sisal fiber reinforced epoxy polymeric composite laminates. The bi-directional sisal fiber was treated with an alkali (NaOH) and laminated specimens were fabricated by using hand-layup method. Furthermore, the present investigation extends to explore the effect of introducing Carbon nanotube (CNT) and MXene (Ti3C2Tx) nanoparticles on the elastic behavior of glass-sisal fiber hybrid composites. The nano-fillers were dispersed and blended with the neat epoxy by using sonication method. The multiscale structure of the MXene dispersed hybrid plates were examined by using scanning electron microscopy. It was found that the tensile strength of the sisal/glass fibers laminate got enhanced by 42% upon reinforcing MXene. In addition, it was observed that the bending strength and bending modulus of sisal/glass fibers laminate was increased by 34% and 30% respectively, when using MXene nanoparticles were reinforced into the matrix. Based on the experimental results, it was inferred that the surface characteristics of the MXene and CNT nanoparticles play a significant role in improving the tensile and flexural properties of the sisal/fiberglass reinforced hybrid laminate.

Polyimide-based composites reinforced by carbon nanotube-grafted carbon fiber for improved thermal conductivity and mechanical property

This paper describes a method to improve the thermal conductivity, mechanical properties and thermal dimensional stability of polyimide-based composites by rationally introducing carbon nanotubes (CNT) chemically-grafted-carbon fiber CF into the polyimide matrix via an ice-templating strategy followed by hot-pressing. The grafted CNT onto CF surface (CNT@CF) significantly increased the roughness of the smooth surface of carbon fiber, improving the interfacial compatibility between CNT@CF and PI matrix and resulting in improved thermal conductivity and tensile strength as well as the dimensional stability. Typically, the PI/CNT@CF20 composite containing 20 wt% CNT@CF exhibits an in-plane thermal conductivity of 4.25 W m−1 K−1, 1134% enhancement compared to the pure matrix (0.34 W m−1 K−1). Meanwhile, the PI/CNT@CF20 composite also presents an increased tensile strength (130 MPa), ∼18 MPa and ∼58 MPa higher than that of PI/CF20 composite (102 MPa) and pure PI (72 MPa), respectively. Besides, the resulting composites exhibit a gradually reduced coefficient of thermal expansion (CTE), which decreases from 66.7 ppm K−1 to 24.7 ppm K−1 as the content of CNT@CF increasing from 0 to 20 wt%. Interestingly, the PI/CNT@CF composites also show good Joule heating performances at low driving voltages. Accordingly, the developed polyimide-based composites demonstrate high potential as advanced thermal management materials with excellent mechanical properties.

Magnetic and electrically conductive polyurethane composites with high content of two functional fillers base on “Root” inspired microstructure

The incorporation of functional fillers into polymer matrix endows composites with functionality, and filler content is an important factor that affects the performance and functionality of composites. In traditional processing methods, excessive filler usually deteriorates the continuity of polymer matrix, leading to composite developing crack or failing to support itself. Hence, the filler content cannot be usually maximized. Not to mention, the incorporation of two functional fillers with large quantity to achieve multi-functionalities. In this work, branched polyurethane (PU) dendrites with large aspect ratio and interpenetrating entangled structure are used to capture functional fillers. By introducing carbon nanotubes (CNTs) and carbonyl iron particles (CIPs) onto these “root” inspired dendritic PU, the resultant PU/CIPs/CNTs composite with PU:CNTs:CIPs weight ratio at 1:0.3:7 demonstrates excellent electrical conductivity of up to 5.2 S/cm, ferrimagnetic property >181.2 emu/g and favorable flexibility. The satisfactory conductivity endows composite the capacity to generate heat as a bias voltage applied according to Joule's law, and saturate temperature of 138.9 °C is developed under 3 V-voltage. Extensive magnetic responses are observed due to the extremely high ferrimagnetism. In combination with conductive property and flexibility, fascinating applications such as magnetic field sensor, magnetic controlled heating and switch are demonstrated, revealing wide promising application prospects of composites especially in flexible multifunctional electronics.