Conductivity Of Carbon Nanotubes Research Articles

A Safe Separator with Heat‐Dispersing Channels for High‐Rate Lithium‐Ion Batteries

AbstractSeparators are becoming increasingly important in both academic research and industrial production as a means of enhancing the performance of lithium‐ion batteries (LIBs), particularly at a high rate. However, fast charge–discharge processes will produce local heat accumulation, which accelerates the local reaction rate of Li+ to form lithium dendrites. Commercial polyolefin separators fail to tackle the above issue due to inferior thermal stability. Herein, a core–shell structure is proposed to reinforce the polyvinylidene fluoride‐hexafluoropropylene (PVDF‐HFP) matrix through encircling carbon nanotube (CNT) by adherent polydopamine (PDA). The core–shell 3D structure with PDA avoids the short circuits caused by the electrically conductive CNT, and meantime, the CNT serves as an effective radiator for dispersing local heat sources verified through finite element analysis. The composite separator allows LIBs to achieve high Li+ conductivity (0.49 × 10−3 S cm−1) and Li+ transfer number (0.74), resulting in a high capacity retention of 87.35% after 800 cycles at 5C. In particular, the safety is confirmed that the composite separator avoids violent growth of lithium dendrites caused by local heat accumulation through phase‐field simulations. This work suggests a promising approach for the fabrication of core–shell nanotube composite separators for high‐rate and safe LIBs.

Accelerating Proton and Electron Transfer Enables Highly Active Fe─N─C Catalyst for Electrochemical CO2 Reduction

AbstractAtomically dispersed Fe─N─C catalysts display great potential for efficient CO production in the field of electrochemical CO2 reduction (ECR), but still suffer from unsatisfactory activity limited by the slow proton and electron transfer during the ECR process. Here, a superior Fe─N─C electrocatalyst is designed by anchoring the individual FeN4 sites and Fe nanoparticles onto highly conductive carbon nanotubes. The resultant catalyst displays a commendable CO partial current density of 16.01 mA cm−2 with a turnover frequency of 3519.6 h−1 at −0.65 V in an H‐type cell, and also exhibits CO selectivity > 90% under high current density over 120 mA cm−2 in a flow cell. This remarkable activity exceeds a host of previously reported Fe─N─C catalysts. The findings indicate that the carbon nanotube facilitates CO production due to its strong capability of electron transport and charge transfer. In situ spectroscopic analysis, controlled experiments, and theoretical calculations reveal that Fe nanoparticles effectively promote water dissociation and the subsequent protonation step, accelerate the formation of *COOH intermediate, and thus greatly enhance the ECR activity.

Polypyrrole@CNT@PU Conductive Sponge-Based Triboelectric Nanogenerators for Human Motion Monitoring and Self-Powered Ammonia Sensing.

Elastic sponges are ideal materials for triboelectric nanogenerators (TENGs) to harvest irregular and random mechanical energy from the environment. However, the conductive design of the elastic materials in TENGs often limits its applications. In this work, we have demonstrated that an elastic conductive sponge can be used as the triboelectric layer and electrode for TENGs. Such an elastic conductive sponge is prepared by a simple way of adsorbing multiwalled carbon nanotubes and monomers of pyrrole to grow conductive polypyrroles on the surface of an elastic polyurethane (PU) sponge. Due to the porous structure of the PU sponge and the conductive multiwalled carbon nanotubes (MWCNTs), PPy on the surface of PU could provide a large contact area to improve the output performance of TENGs, and the conductive sponge-based TENG could generate an output of open-circuit voltage of 110 V or a short-circuit current of 12 μA, respectively. The good flexibility of the conductive PU sponge makes the TENG harvest the kinetic energy of disordered motion with different amplitudes, allowing for human motion monitoring. Furthermore, the porous structure of PU and the synergistic effects of PPy and MWCNTs enable the conductive sponge to sense NH3 as a self-powered NH3 sensor. This work offers a simple way to construct a flexible TENG system for random mechanical energy harvesting, human motion monitoring, and self-powered NH3 sensing.

Piezoresistive Theory and Numerical Calculation for Carbon Nanotube Polymer Composite.

A three-dimensional theory has been established for the piezoresistivity of carbon nanotube (CNT) polymer composites. Based on the Mori-Tanaka method in meso-mechanics theory and considering quantum tunneling effect between CNTs, an approach to calculate equivalent electrical conductivity of composites was proposed. On this basis, a piezoresistive theory, which incorporates the effect of composites' geometric nonlinearity, was developed for CNT polymer composites. The theory is dependent only on some basic physical parameters of the materials. A finite element formula of the theory for the numerical calculation of piezoresistivity was presented from the analysis of both elastic and electric fields. Numerical simulations demonstrated that the results predicted by the theory were in good agreement with those of the experimental tests. Parameter sensitivity analysis revealed that when both the potential barrier height of the matrix and the initial average separation distance between CNTs increased, the piezoresistivity obviously increased. However, with the increase in aspect ratio and CNT conductivity, the piezoresistivity decreased gradually. A practical engineering application of this theory is also provided.

Tough, self‐healing, and recyclable cross‐linked polyurethane elastomers via synergistic effect of dual dynamic covalent bonds

AbstractBased on the irresistible inherent trade‐off between the mechanical and self‐healing performances of cross‐linked polyurethane materials, there is still an intractable challenge to design efficient self‐healing and tough elastomers, especially in flexible sensors. Herein, a tough, efficient self‐healing, and recyclable cross‐linked polyurethane elastomer (DTPU) was prepared by integrating oxime‐carbamate bonds and thiourethane bonds into the network. The extraordinary mechanical properties and self‐healing performances of DTPU elastomers were related to the synergistic effect of oxime‐carbamate bonds in the main chain and thiourethane bonds in the chemical cross‐linked sites. The existence of dynamic cross‐linked points not only optimized the mechanical properties of DTPU but also provided support for the reversible cleavage and formation of oxime carbamate bond, thus endowing DTPU with efficient self‐healing performance and recyclability. After self‐healing at mild temperatures for 6 h, the self‐healed DTPU elastomers had a tensile strength of 30.27 MPa and a self‐healing efficiency of 95.5%. After multiple hot‐pressing, the original mechanical strength of DTPU was restored to over 100%, exhibiting excellent recyclable characteristics. Additionally, strain sensors based on self‐healing flexible elastomers were fabricated by introducing conductive carbon nanotubes. The strain sensors maintained their electrical conductivity after 3 times self‐healing, demonstrating great potential in healable flexible electronics.

Tailored engineering of zinc carbide triggered by N‐enriched carbon nanotubes for prospective water splitting

AbstractFor practical H2 generation, it is currently difficult to create modules for electrochemical water splitting that are efficient and inexpensive over a broad pH range. In this study, a novel ZnC8@NCNT electrocatalyst is fabricated via simple pyrolysis of melamine with zinc chloride and carbon nanotubes (CNTs). The self‐assembled hybrid material was examined to catalyze the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in an alkaline pH range, and the ZnC8@NCNT responds with a lower OER overpotential of 245 mV, and smaller Tafel slope of 50.0 mV dec−1 with the turnover frequency (TOF) of 0.67 s−1 due to its unique structure. The HER response of the generated material is quite satisfactory with an overpotential of 223 mV and a Tafel value of 107 mV dec−1. The fabricated material supported by conductive CNTs increases the catalytic reactivity due to the synergistic manner, which is superior in performance as a cutting‐edge catalyst for water electrolysis in an electrolytic cell. Furthermore, ZnC8@NCNT establishes as a cost‐effective alternative to expensive Ir, Pt, Pd, and Ru‐based catalysts.

Trifunctional catalyst of FeCo,N-doped mixed-dimensional carbon for the high-performance zinc-air flow battery

Exploring efficient and highly stable non-precious metal trifunctional catalysts is imperative for the practical application of zinc-air flow batteries (ZAFBs) and overall water splitting (OWS). Herein, the FeCo and nitrogen-rich codoped one-dimensional carbon nanotubes cross-interpenetrated with birdhouse-like carbon nanosheets in mixed-dimensional carbon structure (FeCo,N-MDC) is constructed by a facile and universal method. Benefiting from the merits of hyper-dispersed FeCo-N/Ox and FeCo alloy active sites, high density of pyridine and graphitic nitrogen, ultra-high conducting carbon nanotubes, large surface area, and massive mass transfer channels can synergistically promote multifunctional catalysis. The resulting FeCo,N-MDC exhibits superior trifunctional activities with onset potential and half-wave potential of 0.994 V and 0.861 V for oxygen reduction reaction in 0.1 M KOH, oxygen evolution reaction and hydrogen evolution reaction overpotentials of 0.341 V and 0.272 V at 10 mA·cm−2 in 1 M KOH, respectively, and have long electrochemical stability. Moreover, the FeCo,N-MDC-based ZAFB has an open-circuit voltage of 1.517 V, a specific capacity of 808 mAh·g−1, the remarkable running stability for 300 h, which surpassed that of commercial Pt/C + RuO2 hybrid-driven device. Additionally, the hydrophilic FeCo,N-MDC, as both the anode and cathode electrodes, also display a hydrolysis reaction voltage of 1.603 V to deliver a current density of 10 mA·cm−2 and outstanding durability. What is more, the continuously mass-produced FeCo,N-MDC, and the alternative CoFe, N-MDC catalysts exhibit excellent performance in the same water-solvent environment. This effort presents a facile strategy for rationally designing economical and efficient mixed-dimensional catalysts for zinc-air flow batteries and more energy devices.

Influence mechanism of functionalization of CNTs on the thermal transport property of their nanofluids

Carbon nanotube (CNT) nanofluids have promising application prospects as the working fluids in energy and power systems due to their prominent thermal properties, while the poor stability of CNT nanofluids is one of the biggest obstacles to their practical application. The addition of functional groups on CNTs is a good method to improve the dispersion of CNT nanofluids, while the influence mechanism of this strategy on the thermal transport property is not clear. In this work, the thermal conductivities of CNT, CNT-OH, and CNT-COOH nanofluids were investigated by experiments and molecular dynamics (MD) simulations to reveal the influence mechanism of functionalization on the thermal transport ability of CNT nanofluids. Both experimental measurements and MD simulations indicate the significant suppression of functionalization on the thermal transport property of CNT nanofluids. Furthermore, the influence mechanism of functional groups on the thermal conductivity of CNT nanofluids has been revealed by analyzing the effect of the thermal conductivities of CNTs, the formation of hydrogen bonds, the mean square displacement of water molecules, and the interlayer thermal resistance of CNT and water. This work is helpful to the utilization of CNT nanofluids as working fluids in energy systems.

Scalable, roll-to-roll manufacturing of multiscale nanoparticle/fiber composites using electrophoretic deposition: Novel multifunctional in situ sensing applications

Multiscale composites, where traditional fiber reinforcements are combined with nanoscale reinforcements, have emerged as multifunctional materials and have found potential for in situ strain and damage sensing, and energy harvesting/storage applications. Critical to the advancement of future applications is the development of manufacturing techniques that are industrially scalable. Electrophoretic deposition (EPD) can uniformly coat functionalized nanoparticles, such as carbon nanotubes (CNT), on conductive and non-conductive fiber substrates, producing multiscale composites with controlled microstructures and functional properties. In this research, a pilot-scale roll-to-roll EPD system is developed to continuously manufacture CNT-integrated fabrics for in situ sensing applications. Based on fundamental knowledge of CNT deposition mechanisms, key experiments are conducted to determine electrode configurations to optimize deposition yield in the roll-to-roll process. Functionalized CNTs are then deposited on 4–6 m long continuous rolls of randomly oriented non-woven glass fiber veil with different areal weights, and the CNTs form a continuous, conductive fiber-level coating. The thin and open fabric microstructure allows embedded sensors that are minimally invasive to the composite structure and allow ultraviolet (UV) light transmittance for use with UV-curable resins. The electrically conductive CNT network created on the fabric allows for the integration of sensing functionality. Short beam specimens with the CNT sensors embedded at the midplane showed no deterioration in strength. Multiple functionalities, including strain sensing and flow/UV cure monitoring during vacuum infusion are demonstrated. Sensors tested under flexural loading demonstrated sensitivity in tension and compression, and during resin infusion, the sensors could track resin flow and cure progression.

Nanoscale Dispersion of Carbon Nanotubes in a Metal Matrix to Boost Thermal and Electrical Conductivity via Facile Ball Milling Techniques.

Carbon nanotube (CNT)/metal composites have attracted much attention due to their enhanced electrical and thermal performance. How to achieve the scalable fabrication of composites with efficient dispersion of CNTs to boost their performance remains a challenge for their wide realistic applications. Herein, the nanoscale dispersion of CNTs in the Stannum (Sn) matrix to boost thermal and electrical conductivity via facile ball milling techniques was demonstrated. The results revealed that CNTs were tightly attached to metal Sn, resulting in a much lower resistivity than that of bare Sn. The resistivity of Sn with 1 wt.% and 2 wt.% CNTs was 0.087 mΩ·cm and 0.056 mΩ·cm, respectively. The theoretical calculation showed that there was an electronic state near the Fermi level, suggesting its electrical conductivity had been improved to a certain extent. In addition, the thermal conductivity of Sn with 2 wt.% CNTs was 1.255 W·m-1·K-1. Moreover, Young's modulus of the composites with CNTs mass fraction of 10 wt.% had low values (0.933 MPa) under low strain conditions, indicating the composite shows good potential for various applications with different flexible requirements. The good electrical and thermal conductive CNT networks were formed in the metal matrix via facile ball milling techniques. This strategy can provide guidance for designing high-performance metal samples and holds a broad application potential in electronic packaging and other fields.

Ultrathin, Large‐Area, and Multifunctional Polarizer Based on Highly Ordered Carbon Nanotubes Produced by Simple Shear Flow

AbstractAligning carbon nanotubes (CNTs) with high orientational ordering in a 2D array is essential for realizing optical polarizers with high polarization efficiency over a wide spectral range. Two methods are reported: dispersing CNTs in a polymer matrix followed by stretching, and mechanical stretching of a vertically grown CNT forest and then transferring it onto a substrate. However, neither can realize nanometer‐thin or large polarizers. Herein, a novel approach is demonstrated to construct a large and thin (150 nm) conductive CNT polarizer by achieving liquid crystal (LC) phase of size‐controlled CNTs in chlorosulfonic acid, unidirectional shearing, and then drying. The polarizer exhibits an excellent polarization efficiency of 98.4% for ultraviolet (365 nm) and 96.0% for visible light (550 nm). This performance is maintained even at 400 °C, while the conventional iodine‐type polarizer starts to lose efficiency over 100 °C. The CNT polarizer with high polarization efficiency for UV can replace the costly nano‐patterned wire‐grid polarizers currently used for photoaligning LCs and also its multifunction playing role of polarizer, electrode, and LC alignment is confirmed with switching of LC device. This study provides a new paradigm for realizing ultrathin and large CNT polarizers for broadband applications with outstanding heat resistance.

Design of efficient thermal conductive epoxy resin composites via highspeed transport pathways of heterogeneous compatible carbon framework

Thermal interface materials are crucial for addressing the hot issues of a rapid increase in thermal density in narrow and limited service spaces. Flexible and designable epoxy resin (EP) based composites are competitive choice yet lacks desirable thermal conductivity (∼0.2 W m−1 K−1) and mechanical properties (tensile strength: ∼19.6 MPa). Herein, EP-based composites with a reinforced three-dimensional (3D) interconnected carbon material architecture were prepared by in-situ growing 1D carbon nanotubes (CNTs) on the surface of 2D carbon fiber braid (CFB) and infiltrating matrix EP. CNTs not only promote the wettability between carbon fibers inside CFB and EP but also observably bridge the adjacent carbon fibers. The analysis of numerical models reveals the prominent contribution of 3D CFB/CNTs network to a significant increase in thermal conductivity. Non-equilibrium molecular dynamics (NEMD) indicates the high intrinsic thermal conductivity of CNTs in both systems: single CNT model and CNT/Ni model. The coupling behavior of high-frequency phonons at the interface contributes to the in-plane thermal transport. The in-plane thermal conductivity of 7.86 W m−1 K−1 and the through-plane thermal conductivity of 5.85 W m−1 K−1 are obtained in the composites with 23.2 wt% hybrid fillers, increased by 3830 % compared to neat EP. The tensile (58.93 MPa) and compressive strength (138.83 MPa) are also enhanced, meeting practical demands. These properties even perform no obvious changes after 100 cycles of bending. The stable and reliable EP-based composites with outstanding comprehensive performance designed by this work have enormous application potential in the advanced heat dissipation system.

Preparation of an Activated Carbon Composite with High Thermal Conductivity Based on Emulsified Asphalt and Carbon Nanotubes and its Adsorption Performance for n‐Hexane

AbstractActivated carbon, as the main adsorption material for treating VOCs, has been widely used. To solve the problem of safety hazards in activated carbon adsorption process due to the large amount of heat released, highly thermally conductive composite activated carbon (A‐AC/CNTs) was prepared using asphalt and highly thermally conductive carbon nanotubes (CNTs) for thermal conductivity improvement. Uniform dispersion and firm loading of CNTs in the carbon production material were achieved by dispersing carbon nanotubes (CNTs) in the asphalt‐in‐water emulsion. Experimental results showed that the specific surface area of A‐AC/CNTs reached a maximum when the loading of CNTs was 0.5 wt %. Meanwhile, the thermal conductivity increased by 1.5 times compared with the original activated carbon. The adsorption capacity of n‐hexane reached the maximum of 2868 mmol ⋅ g−1, and the adsorption capacity increased by 21.41 %. It also maintained good regeneration performance after dynamic adsorption experiments.

Role of non-covalent interactions in 2,5-di-Me-pyrazine-di-N-oxide - tertiary butyl alcohol - single-walled and multi-walled carbon nanotubes electrocatalytic systems

Oxidation of tert-butyl alcohol (tert-BuOH, Me3COH), a compound with a high C-H bond breaking energy in the absence of precious metals or their oxides as catalysts and using metal-free electrodes, is an inexpensive process and is of interest for practical applications in electrocatalysis and sensors. In this work, electrocatalytic systems 2,5-di-Me-pyrazine-di-N-oxide (Pyr1) - tert-BuOH – single - walled (SWCNT) and multi-walled (MWCNT) carbon nanotube paper electrodes in 0.1 M Bu4NClO4 solution in acetonitrile (MeCN) were studied by the methods of cyclic voltammetry, quantum chemical modeling and electron paramagnetic resonance (EPR) electrolysis. Calculaition of energies of non-covalent interactions between the components of the electrocatalytic system in complexes Me3COH*Me3COH, Me3COH*MeCN, Pyr1*Me3COH and the adsorption energy of Me3COH and complexes of Pyr1*Bu4NClO4, Pyr1*Me3COH, Pyr1*MeCN and Me3COH *Bu4NClO4 on CNTs surface using a cluster model describing the surface of conducting carbon nanotubes (10, 10) was performed. The study made it possible to reveal the regularities characteristic of aromatic-di-N-oxide – CNT electrocatalytic systems and to propose a mechanism of tert-BuOH oxidation in the presence of electrochemically generated radical cation Pyr1. The data will be useful at using CNT electrodes in electrocatalytic processes, as well as aromatic di-N-oxide-CNT catalytic systems in electrocatalysis and sensors.

Nano GeSe2/C anchored in carbon sponge skeleton for free-standing flexible lithium-ion battery electrodes

As a typical conversion alloyed anode material, Germanium selenide (GeSe2) exhibits isotropic lithiation behavior and high theoretical charge-discharge specific capacity. However, pure GeSe2 anode faces significant volume expansion (∼250 %−360 %) and further exploration is needed in the preparation of flexible electrode materials and structural design. Herein, a simple strategy is designed to load GeSe2/C-2 nanoparticles with porous carbon-coated structure on a flexible cross-networking substrate. The 3D network substrate is composed of highly conductive carbon nanotubes and adhesive cotton cellulose fibers. A two-step method involving coating and cross-linking is designed to achieve the fabrication of self-supporting flexible electrodes. As an anode for LIBs, the one layer GeSe2 discs with ∼0.65 mm thickness manifest capacities of 827.1, 744.4, 676.3, and 472.9 mAh g−1 at 0.1, 0.2, 0.5, and 1 A g−1, respectively. This superior Li+ storage performance can be attributed to the positive collective impact from the integration of nano-scale material, low crystalline properties, and carbon sponge skeleton. Furthermore, the GITT tests indicate that the diffusion coefficient of Li+ in the GeSe2-based electrodes ranged from 10−15 to 10−12 cm2/s, and the thickness of the flexible electrode (including two layers) has a negligible impact on its electrochemical performance.

Single Ru Sites on Covalent Organic Framework-Coated Carbon Nanotubes for Highly Efficient Electrocatalytic Hydrogen Evolution.

Covalent organic frameworks (COFs) with precisely controllable structures and highly ordered porosity possess great potential as electrocatalysts for hydrogen evolution reaction (HER). However, the catalytic performance of pristine COFs is limited by the poor active sites and low electron transfer. Herein, to address these issues, the conductive carbon nanotubes (CNTs) are coated by a defined structure RuBpy(H2 O)(OH)Cl2 in bipyridine-based COF (TpBpy). And this composite with single site Ru incorporated can be used as HER electrocatalyst in alkaline conditions. A series of crucial issues are carefully discussed through experiments and density functional theory (DFT) calculations, such as the coordination structure of the atomically dispersion Ru ions, the catalytic mechanism of the embedded catalytic site, and the effect of COF and CNTs on the electrocatalytic properties. According to DFT calculations, the embedded single sites Ru act as catalytic sites for H2 generation. Benefitting from increasing the catalyst conductivity and the charge transfer, the as-prepared c-CNT-0.68@TpBpy-Ru shows an excellent HER overpotential of 112mV at 10mA cm-2 under alkaline conditions as well as an excellent durability up to 12h, which is superior to that of most of the reported COFs electrocatalysts in alkaline solution.

Synthesis of highly thermal conductive carbon nanotubes on cellulose nanofiber film-loaded polyethylene glycol phase change material with flame retardancy by layered double hydroxide

The nitrogen-doped carbon nanotubes (CNTs) were obtained by using methyl orange as a soft template and high temperature treatment, on which the layered double hydroxide (LDH) was grown in situ by hydrothermal method, and finally mixed with the phase change materials (PCM) by vacuum filtration to obtain a series of novel composite films with great flame retardancy and thermal conductivity. The use of cellulose nanofiber (CNF), polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) as PCM increased the film-forming properties, and the CNTs could improve the thermal conductivity of composites, while reducing the agglomeration of LDH nanolayers and improving the flame retardancy of the composite films. The results showed that the LDH grown on the nanotubes had a typical hexagonal lamellar structure, and its uniform distribution was the fundamental reason for the flame retardancy of the films which was verified by defined combustion experiments, the shortest self-extinguishing time and the least unburned area were achieved at a mass ratio of 7.14 % of LDH material. The melt and crystallization enthalpies of the thermally conductive flame-retardant films were 74.65 J/g−1 and 74.82 J/g−1, and the thermal conductivity of the material was increased to 0.04129 W/(m·K) after the use of 2.5 % thermally conductive filler. It can reduce the temperature of LED by up to 5.9 °C during the LED opening process and up to 5.2 °C during the LED closing process.

Carbon nanotubes and hexagonal boron nitride nanosheets co‐filled ethylene propylene diene monomer composites: Improved electrical property for cable accessory applications

AbstractRubber‐based composites based on ethylene propylene diene monomer (EPDM) with excellent non‐linear electrical conductivity are preferred to serve as reinforced insulation in cable accessories, which can self‐adaptively regulate electric field distribution and avoid electric field concentration due to the non‐linear conductivity. The conductive carbon nanotubes (CNT) are filled into EPDM to improve the non‐linear conductivity, while the insulating hexagonal boron nitride nanosheets (h‐BN) are used to reconcile the electric breakdown strength. The results show that with the increase of CNT loading content, the non‐linear conductivity of CNT/h‐BN/EPDM composites becomes more prominent, accompanying the decrease of threshold field strength and increase of non‐linear coefficient. However, the electric breakdown strength of CNT/h‐BN/EPDM composites seriously deteriorates due to the increase of CNT content and temperature. By incorporating 10 wt.% h‐BN into the composites, the reduction percentage of breakdown strength can be significantly lowered, which is 19.95% of neat EPDM and 13.74% of CNT/h‐BN/EPDM composites at 70°C, respectively. The COMSOL Multiphysics simulation results demonstrate that using the CNT/h‐BN/EPDM composite as the reinforced insulation can eliminate the electric field concentration of the cable accessory as well as enable the cable accessory with good lightning shock resistance.

In-situ damage self-sensing and strength recovery activated by self-electricity in carbon fibrous composites embedded with multi-functional interleaves

It is challenging to simultaneously in-situ monitor and then repair the delamination crack of carbon fiber reinforced plastics (CFRPs) without sacrificing the initial mechanical properties. Herein, two sandwich interleaves are prepared by using healable poly (ethylene-co-methacrylic acid), reinforced and conductive carbon nanotubes (CNTs), and shear-resistant epoxy columns, to achieve self-sensing and self-healing functionalities. The results reveal that both interleaves show significant self-resistance changes to damage initiation and tensile strength of the interleaves themselves can be restored to 67.9–69.1%. Also, the interleaved CFRP exhibits obvious resistance change features during the progressive damage process after multiple healings. Moreover, a self-healing efficiency of more than 90% to interlaminar shear strength after two damage-healing cycles can be obtained. Furthermore, the interleaf with more CNTs possesses higher initial and healed strength. Therefore, the proposed interleaves can be used to prepare CFRP structure with self-sensing and self-healing functions, thereby with improved service reliability and service life.

Liquid oxygen compatibility study: carbon nano-tubes based CFRP composite

This study focuses on developing a LOX-compatible PMC material by enhancing its thermal conductivity. An innovative technique involving the integration of high thermally conductive carbon nanotubes (CNTs) onto carbon fibers (CF) was employed, followed by impregnation with cyanate ester (CE) resin. The LOX compatibility of CE resin-only, CF impregnated with CE resin (CF/CE), and the proposed CNT-modified CF composite (CNTs-CF/CE) was investigated according to ASTM D2512 guidelines. While the CE resin-only samples exhibited no reaction, CF/CE and CNTs-CF/CE composites reacted with a flash event during the LOX compatibility test. Further investigation revealed that the introduction of CNTs in the CF/CE composite increased the LOX reaction probability. Notably, the study identified the influence of the damage level on the ignition rate, emphasizing the importance of damage assessment. These findings underscore the potential of CNTs in enhancing LOX compatibility and contribute valuable insights toward the development of efficient LOX storage tank applications.