Preparation and properties of carbon nanotube/carbon fiber hybrid reinforcement by a two-step aryl diazonium reaction

Abstract

Raw carbon nanotube (CNT)/carbon fiber (CF) hybrids were achieved through a two-step aryl diazonium reaction in mild, eco-friendly conditions. Raman spectra, Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) confirmed the grafting of CNT onto the CF surface. The surface topography and surface free energy of the modified CFs were examined by scanning electron microscopy (SEM), transmission electron microscope (TEM) and dynamic contact angle (DCA) tests, respectively. The resulting CNT/CF hybrid formed a strong chemical bond between the fiber and matrix and enhanced the surface wettability of the modified CFs. The interfacial shear strength (IFSS) of the CNT/ CF hybrid reinforced composites increased by 104% compared with that of the untreated CFs. Moreover, the mechanical properties of the CNT/CF hybrid showed a slight improvement after modification.

Single Carbon Fibers with a Macroscopic‐Thickness, 3D Highly Porous Carbon Nanotube Coating

“…Here, from a macroscopic view, a unique feature of our CVD process is that the CNTs deposit around the fiber surface uniformly, yielding a very thick layer covering the CF. The thickness of our CNT layer is 2–3 orders of magnitude higher than most of reported hybrid fibers …”

“…Currently, many methods such as solution impregnation, chemical grafting, electrophoretic deposition, and chemical vapor deposition (CVD) have been developed to fabricate CNT‐grafted CF structures . Among these methods, the CVD process is most widely used, which directly grows a layer of CNTs on the CF surface; however, it typically yields short and random CNTs with layer thicknesses of a few to 20 µm . Short CNTs provide very limited contact area with the polymeric matrix, and the small layer thickness is not sufficient to penetrate into surrounding matrix thus generating strong interlocking effect.…”

“…As the CNTs are directly grafted on the CF surface, the CNT–CF interface plays a critical role in efficient load transfer between the matrix and CFs, which also prevents the slippage or pull‐out of CFs under loading. Surface treatment by functional groups may introduce chemical bonding between CNTs and CFs to enhance the interfacial adhesion, but this method only applies to very small amount of CNTs dispersed on the CF surface . For CVD‐grown CNT‐grafted CF structures, there still lack effective ways to improve the adhesion and even to quantitatively analyze the interfacial strength between the CNT layer and underlying CFs.…”

Chemical grafting of salicylaldehyde onto carbon fiber for enhancing interfacial strength of silicone resin composites

“…The intense peaks close to 3600‐3300 cm −1 may be due to hydroxyl groups stretching vibration of phenolic OH or water . Additionally, the new peaks at around 1518 and 1449 cm −1 are assigned to the stretching vibration of CC arising from substituted aromatic ring . More importantly, the bands at 1637 cm −1 can be very safely attributed to CN stretching vibration in the spectrum of CF‐g‐SLDH, confirming that salicylaldehyde has been successfully grafted onto the fiber surface.…”

Fabrication and multifunctional properties of polyimide based hierarchical composites with in situ grown carbon nanotubes

“…Many researchers found that the most effective way is improving the surface activity of the bers and thus improving the interfacial bonding strength between ber and matrix by ber surface treatments. [12][13][14][15][16][17][18] In these methods, carbon nanotubes (CNTs) directly graing 19 or growing on the surface of ber have been attracting the researcher's interests because it can not only improve the surface activity of the bers and also fundamentally solve the problem of agglomeration of carbon nanotubes. This method shows a lot of advantages compared to other methods.…”