In this study, multiscale MWCNT–glass fiber fabric (MGFf) preforms with multiwalled carbon nanotubes (MWCNTs) dispersed onto commercial E-glass fiber fabric (GFf) was used to fabricate the MGFf multiscale composites. The mechanical properties, interlaminar shear strength (ILSS), dynamic viscoelasticity and thermal conductivity of MGFf multiscale composites were investigated using a universal material testing machine, dynamic mechanical thermal analyzer and transient plane source method. Furthermore, the reinforcing mechanisms of MWCNTs on interlaminar adhesion of MGFf multiscale composites were explored using scanning electron and transmission electron microscopy and energy dispersive X-ray spectrometry. Compared with the GFf composite, the ILSS and thermal conductivity of MGFf multiscale composites were increased by 40.5% and 55.3%, respectively; both of the tensile and flexural properties of MGFf multiscale composites were significantly enhanced; the glass transition temperature of MGFf multiscale composites was also raised. In addition, the interface thickness was increased with the addition of MWCNTs, and MWCNTs in MGFf multiscale composites behaved as hooked fibers to improve the interlaminar adhesion. The work demonstrates the great promise of MGFf preforms toward practical industrial application in manufacturing multifunctional fiber composites with high strength and modulus, high shear resistance and good thermal conductivity.

Three types of multiwall carbon nanotubes (MCNTs)/glass fiber fabrics (MGf) were prepared by dispersing industrial-grade MCNTs onto commercial E-glass fiber fabrics (GFfs) through an ultrasonic-assisted impregnation deposition method. The multiscale MGf-reinforced composites were fabricated by the vacuum infusion process. The effect of γ-aminopropyltrimethoxysilane (APS) or APS hydrolysis on the MCNT dispersion and the interfacial bonding between MCNTs and glass fiber were investigated by Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, energy dispersive X-ray spectroscopy and their flexural stiffness, respectively. The interfacial adhesion of MGf composites was evaluated by interlaminar shear strength (ILSS) and dynamic mechanical thermal analysis. The results indicated that MCNTs on the MGf surface could form an interpenetrating network and act as anchors to interlock glass fiber with epoxy. The initial storage modulus and glass transition temperature of the MGf composites clearly increased, while the first loss factor of the MGf composites decreased by 30.0–45.0% compared with that of the GFf composite. Whether or not APS was hydrolyzed, it helped the MCNTs disperse on the GFf surface by chemical bonds. The ILSS of the multiscale composite with APS-treated MCNTs was enhanced significantly, while that with hydrolyzed APS-treated MCNTs (MGf-h) had a slight increase. APS hydrolysis increased the flexural rigidity of the MGf-h.

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Multi‐walled carbon nanotubes (MWCNTs) with various aspect ratios were first designed onto the glass fiber fabric (Gf), for the purpose of fabricating a series of MWCNT–glass fiber fabric (MGf) composites with controllable interlaminar fracture toughness, adhesion and mechanical properties. The dispersal ability of MWCNT on the Gf surface was closely related to its aspect ratios, which may greatly affect the toughness and strength of epoxy‐based composites. An interesting result showed that the interlaminar fracture toughness of MGf composites with MWCNT aspect ratios of ~667 to ~1333 was significantly improved. Under an optimal MWCNT aspect ratio (~1333), the interlaminar shear, tensile and flexural strength of the MGf composite were raised by 43.8, 38.2, and 34.2%, respectively, and its dynamic mechanical properties had a similar rule, as compared with neat Gf composite. Almost all the MGf composites with MWCNT exhibited some ductile fracture behavior whether in tensile or flexural tests. POLYM. COMPOS., 40:E1329–E1337, 2019. © 2018 Society of Plastics Engineers

In this study, an ultrasonic-assisted impregnation method was employed to deposit carboxyl multiwalled carbon nanotubes (MWCNTs) onto the E-glass fiber fabric (GFf) for the preparation of the MWCNT-GFf reinforcer. The effects of ultrasonic power, duration and temperature on the dispersion of MWCNTs onto GFf were investigated, and the mechanical properties, interlaminar adhesion, and dynamic viscoelasticity of the resulting MWCNT-GFf-reinforced composites (MGCs) were evaluated. The results indicated that an effective dispersion of MWCNTs onto GFf without obvious breakage of the MWCNTs was achieved under an ultrasonic power of 600 W, duration of 6 min, and processing temperature of about 0°C. Compared with the GFf-reinforced composite, the tensile strength, flexural strength and interlaminar shear strength of the MGCs exhibited maximum increments of 38.4%, 34.6% and 47.1%, respectively. Moreover, the storage moduli and glass-transition temperatures of the MGCs were significantly enhanced. The ultrasonic parameters were of key importance for dispersing MWCNTs onto GFf and improving the interfacial properties of the composites.

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In this article, potassium hexacyanoferrate (K3Fe(CN)6) was introduced into poly(3,4-ethylenedioxythiophene) (PEDOT) hydrogel by in situ polymerization to prepare K3Fe(CN)6-doped PEDOT hydrogel. The specific capacitance of PEDOT hydrogel was efficiently increased by the doping effect of K3Fe(CN)6. The increase in capacitance achieved by introducing K3Fe(CN)6 into PEDOT hydrogel was attributed to the doping effect of anionic ferricyanide/ferrocyanide couple. The specific capacitance of PEDOT hydrogel increased from 38 F g−1 to the maximum value of 98 F g−1 (current density = 500 mA g−1) when the concentration of K3Fe(CN)6 reached 5 mM. On the basis of cycle life tests, the capacitance retention of about 75% for the doped PEDOT hydrogel after 5000 cycles suggested a high cycle stability of redox-active PEDOT hydrogel and its potential as an electrode material for supercapacitor applications.