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The synergistic effect of CNT and three-dimensional N-doped graphene foam (3DNG) on improving corrosion resistance of zinc-reinforced epoxy (ZRE) composite coatings was studied in this work. Although CNT itself was demonstrated to be effective to promote the anti-corrosion performance of the ZRE coating, the incorporation of additional 3DNG leads to further enhancement of its corrosion resistance under the synergistic effect of the hybrid carbon nanofillers with different dimensions. Both the content of the carbonaceous fillers and the ratio between them affected the performance of the coating. The optimal content of hybrid filler in the coating was determined to be only 0.1% with 3DNG:CNT = 1:3. With the modification of hybrid fillers, the corrosion current of the coating could be reduced by more than six orders of magnitude. Additionally, the immersion test of the pre-scratched coating directly demonstrated the evident contribution of the hybrid fillers to the sacrificial anode-based surface protection mechanism of the coating. These results confirmed the synergistic effect of the hybrid 1D and 3D carbonaceous fillers on promoting the corrosion inhibition of their coating, which could be promising for application in other functional composites. [ABSTRACT FROM AUTHOR]

In this study, hierarchical short carbon fibers (SCFs) synthesized with carbon nanotubes (CNTs) were used as CNT-SCF interleaves to increase the mode I delamination fracture energy G IC of carbon fiber/epoxy (CF/EP) composite laminates. Even at a relatively low CNT-SCF areal density, 1.0 mg/cm 2 , G IC (1.17 kJ/m 2 ) was increased by 125% compared to the control laminates (0.52 kJ/m 2 ), which is a very high value compared to those results obtained by other interleaving methods in CF/EP laminates. The toughening effects of SCFs in bulk epoxy and interleaved CF/EP laminates were also studied to better understand the failure mechanisms of the hierarchical CNT-SCF structure. SEM observations revealed synergistic toughening mechanisms in these CNT-SCF interleaved CF/EP laminates. [ABSTRACT FROM AUTHOR]

A simple flame synthesis method was utilized for grafting functional carbon nanotubes (CNTs) onto carbon fiber fabrics. Functional organic groups found on CNTs were formed after the flame growth process. Results from electrochemical tests also showed that the accessible surface area was improved by more than 50 times after the carbon fiber fabrics were grafted with CNTs for 3 min. Hence, mode I and mode II interlaminar fracture toughness of these composite laminates, wherein carbon fiber fabrics were grafted with CNTs, increased by ∼67% and ∼60%, respectively. [ABSTRACT FROM AUTHOR]

Abstract: A simple one-step method of the synthesis of carbon nanotubes (CNTs) grafted onto carbon fibers (CFs) was developed using catalysts formed in an ethanol flame, where the reducing atmosphere prevents the CFs from combustion and reduces the catalyst precursor to catalyst particles on the fibers. The growth process was studied and both the type and concentration of catalyst ions were found to affect CNT growth on CFs. The peeling force to separate the interfacial bonding between a CNT and a CF substrate was also measured by an instrumented tip of an atomic force microscope. [Copyright &y& Elsevier]

Urchin-like tungsten oxide (WO3) microspheres self-assembled with nanobelts are deposited on the surface of the hydrophilic carbon cloth (CC) current collector via hydrothermal reaction. The WO3 nanobelts in the urchin-like microspheres are in the hexagonal crystalline phase, and their widths are around 30–50 nm. The resulted hierarchical WO3/CC electrode exhibits a capacitance of 3400 mF/cm2 in H2SO4 electrolyte in the voltage window of −0.5~0.2 V, which makes it an excellent negative electrode for asymmetric supercapacitors. To improve the capacitive performance of the positive electrode and make it comparable with that of the WO3/CC electrode, both the electrode material and the electrolyte have been carefully designed and prepared. Therefore, the hydrophilic CC is further coated with carbon nanotubes (CNTs) to create a hierarchical CNT/CC electrode via a convenient flame synthesis method, and a redox-active electrolyte containing an Fe2+/Fe 3+ couple is introduced into the half-cell system as well. As a result, the high performance of the asymmetric supercapacitor assembled with both the asymmetric electrodes and electrolytes has been realized. It exhibits remarkable energy density as large as 403 μW h/cm2 at 15 mW/cm2 and excellent cyclic stability after 10,000 cycles. [ABSTRACT FROM AUTHOR]

An analytical model was developed to study the interlaminar fracture behaviour of polymer composite reinforced by carbon fibres grafted with carbon nanotubes. Delamination properties, such as load with displacement or crack (R-curve) and toughness with crack (GR-curve), can be obtained from this model. The bridging laws presented, based on the CNT pullout mechanism (CNT pullout from polymer matrix) and the CNT sword-in-sheath mechanism (CNT breakage), were incorporated into the proposed analytical model to investigate the influence of the structure of CNT growth onto CFs (CNT@CFs) on delamination properties. The numerical results showed that different toughening mechanisms led to different features of GR-curves, R-curves, and load with displacement curves. Parametric study demonstrated that strengthening the CNT@CF interface resulted in significant improvement in toughness. Further, it was found that elastic deformation of CNTs played an important role in the toughness improvement in the CNT sword-in-sheath mechanism, but no such role was evident in the CNT pullout mechanism. [ABSTRACT FROM AUTHOR]

The alignment of carbon nanotubes (CNTs) with residual catalyst Ni particles in epoxy resin (EP) was achieved under a low magnetic field of 0.4 T. EP composites containing different loading of CNTs were prepared at 60 °C based on the rheology results of CNT/EP suspensions. The effects of CNT loading and magnetic field on the fracture toughness ( K IC ), glass transition temperature ( T g ) and electrical properties of the composites were studied. The obtained results showed significant enhancements in K IC , independent of the orientation of the CNTs, compared to neat epoxy. The maximum increase (∼51%) was achieved by composites with 3 wt.% aligned CNTs transverse to crack growth. Additionally, composites with magnetically aligned CNTs displayed anisotropy in K IC . Compared to CNT/EP composites with no applied magnetic field, the K IC increase was less effective at high CNT loading. Finally, toughening mechanisms, T g and electrical conductivity results were discussed. [ABSTRACT FROM AUTHOR]

A novel one-step flame synthesis method was used to coat carbon nanotubes (CNTs) onto plain weave S-glass fibre (GF) fabrics. Nickel chloride, as a catalyst, was applied on the GF fabrics, and CNTs were formed in an ethanol flame. Results showed that different carbon materials were synthesised, and they were sensitive to the flame synthesis parameters. Short CNTs (shorter than 0.5 μm) were dominant with a low catalyst concentration of 0.2 mol/L, and long CNTs (lengths of ~1.2–2.0 μm) started to appear when the catalyst was increased to 0.4 and 0.6 mol/L. With even higher catalyst concentration at 0.8 and 1.0 mol/L, most of the CNTs were embedded in a thick layer of carbon soot. In addition, the thermal and electrical conductivities of GF/epoxy and multi-scale CNT-GF/epoxy composites were measured. Compared to GF/epoxy composite, a more than 40% increase of thermal conductivity and 10 orders of magnitude decrease of electrical resistance were achieved in these multi-scale CNT-GF/epoxy composites. • CNTs were successfully synthesised in an ethanol flame and coated onto glass fibres. • Catalyst concentration influenced significantly the composition of the synthesised carbon materials. • The multi-scale CNTs-glass fibre composite laminates exhibited enhanced thermal and electrical conductivities. [ABSTRACT FROM AUTHOR]

Highlights • CNTs were decorated by in situ flame catalytic growth of carbon nanoparticles or CNTs. • Carbon particles were deposited onto both inner and outer tubular wall surface of CNTs. • The nano-confinement effect of CNTs led to deposit shorter thinner curved CNTs. • The hierarchical carbon materials exhibit higher capacitance and superior cycling stability. Abstract Hierarchical carbon structures with in-situ growth of small carbon particles on thick CNT (TCNT) were synthesized by a simple flame synthesis method. TEM tomography analysis indicated that flame synthesized CNT (FCNT) with different length and diameter (or carbon sphere particles) were deposited onto both the inner and/or outer tubular wall surface of the TCNT. The nano-confinement effect of the TCNT tubular space on the flame growth of carbon particles was investigated, which led to the formation of shorter and curved FCNT. Electron microscopy studies revealed that the tip growth mechanism dominated the ethanol flame-induced CNT synthesis process and the rate determining step for the flame growth of CNT was the nickel-catalyzed carbon deposit reaction rather than the mass transfer of the carbon source in the confined nano-channels of the TCNT. The influence of the type of metal catalyst on the products was also studied. Substantial improvements of electrochemical properties of TCNT after the decoration with FCNT confirmed the effectiveness and advantages of this method. The FCNT/TCNT anodes delivered a higher reversible lithium ion storage specific capacity than that of the pristine TCNT. [ABSTRACT FROM AUTHOR]

Laser-assisted automated fibre placement (LATP) is an emerging technology for manufacturing thermoplastic composite components. However, major challenges are still encountered for the LAFP process for glass fibre (GF) reinforced composites due to the high near-infrared (NIR) laser reflectance and transmission as well as resulting poor absorption of prepreg constituents. Inspired by the efficient light-trapping and photothermal characteristics of carbon nanotube (CNT) forest, we fabricate CNT forest onto the GF surface by rapid and low‐cost flame synthesis method, to enhance the photothermal conversion efficiency of poly-ether-ether-ketone (PEEK)/GF prepregs during LAFP process. CNT forests with different lengths, alignments and densities were produced by changing flame synthesis parameters. The spectroscopy results show that CNT forest suppresses transmission and reflection from GF and crystals in GF/PEEK prepreg within the NIR wavelength range at near normal incidence, decreasing transmission and reflectance to 0.3% and 7.9%, respectively, and increasing absorption to 91.8% at 1080 nm wavelength. Furthermore, CNTs forest improves the heating rate of GF/PEEK prepreg by more than 700% for a wide range of incident angles. Consequently, CNT forest enables a 400% increase in placement speed and a 79% reduction in energy consumption during LAFP process, while making negligible voids in the interlayer. [Display omitted] • Carbon nanotube (CNT) forest was fabricated onto the glass fibre (GF) surface by rapid and low‐cost flame synthesis method. • A high laser absorption (91.8%) of GF/PEEK prepregs at 1080 nm wavelength was achieved with the light-trapping CNT forest. • Excellent interlaminar adhesion was achieved during the LAFP process with the improved photothermal conversion efficiency. • CNT forest enables a 400% increase in placement speed and a 79% reduction in energy consumption during the LAFP process. [ABSTRACT FROM AUTHOR]

Abstract: The versatile electrospinning technique was used to successfully align and disperse multiwalled carbon nanotubes (MWCNT) in nylon 6,6 matrix to obtain composite fibers. The morphology of the composite fibers and the dispersion of the CNTs within the fibers were analyzed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. TEM analysis revealed that the CNTs were well-dispersed, separated and aligned along the fiber axis. The thermal and mechanical properties of the composite fibers were characterized as a function of weight fraction of the CNTs. Incorporation of the CNTs in the fibers resulted in an increase in glass-transition temperature (Tg ) by ∼7°C, indicating that the addition of CNTs has restricted the mobility of the polymer chains and provided confinement to neighboring molecular chains. Tensile and nanoindentation experiments were performed to investigate the mechanical deformation behavior of the composite fibers. The results suggested that incorporation of high strength and high aspect ratio CNTs into the fiber matrix enhanced significantly the stiffness and strength of nylon 6,6 fibers. An understanding of the structure–property relationships can provide fruitful insights to develop electrospun fibers with superior properties for miniaturized and load-bearing applications. [Copyright &y& Elsevier]

Abstract: To improve the fire retardancy performance of polyamide 6 (PA 6), layered silicates are used in combination with multi-walled carbon nanotubes (CNTs) to address the issue of packing density and uniformity of the protective inorganic barrier formed at the burning surface of the nanocomposites during combustion. Benzimidazolium is used to modify the silicate layers instead of conventional alkyl ammonium surfactants to tackle the issue of thermal stability. However, the poor dispersion of the modified layered silicates in PA 6 has a significant negative effect on the fire performance of the materials and offsets the positive effect of CNTs. Also, the results point to the apparent contradictions with different fire exposure tests; that is, significant reductions in heat release and mass loss rates in the cone calorimetry test do not imply a higher rating in the UL 94 vertical burning test. [Copyright &y& Elsevier]

In this paper, carbon nano bowl array with an octopus sucker-like morphology was fabricated for the first time. A ternary corncob sponge/carbon nanotube/ethylene-vinyl acetate copolymer (CS/CNT/EVA) composite was used as the carbon source and turned into a nano bowl array after a one-step heat treatment. The corncob sponge substrate was carbonized to be a honeycomb-like sponge composed of carbon sheets, and carbon nano bowls originate from EVA were generated on the sheets due to the comprehensive effects of surfactants and CNT, resulting in a carbon nano bowl array structure. This structure endowed the resulting material with a high capacitance of 213.4 F g−1 at a current density of 0.5 A g−1, good rate ability and excellent cycling stability with a loss of less than 2% over 10000 cycles. The solid-state capacitors assembled possess a good energy density of 0.98 W h kg−1 at a power density of 8000 W kg−1. These findings show that our method for fabricating a new kind of carbon nanostructures is promising and that the material obtained is a candidate for supercapacitor electrodes. [ABSTRACT FROM AUTHOR]