Controlled Functionalization of Carbon Nanotubes by a Solvent-free Multicomponent Approach

Abstract

The present work reports the solvent-free, one-pot functionalization of multiwall carbon nanotubes (CNTs) based on the 1,3-dipolar cycloaddition of azomethine ylides using N-benzyloxycarbonyl glycine and formaldehyde. The surface morphology of the functionalized CNTs was investigated by scanning tunneling microscopy. The effect of temperature on the reaction was studied by thermogravimetry and X-ray photoelectron spectroscopy (XPS). XPS was a key technique for the detailed chemical analysis of the CNT surface. The formation of two major reaction products was observed, namely a cyclic benzyl carbamate and a pyrrolidine. The concentration of the two products varied with reaction temperature and time. At 180 °C, the main product was the cyclic benzyl carbamate, while at 250 °C the major product was the pyrrolidine. This simple, solvent-free chemical procedure yields CNTs with fine-tuned surface functionality.

Structure‐property relationship of substituted pyrrolidine functionalized CNT epoxy nanocomposite

“…Similarly, for synthesizing fCNT2, only the aldehyde used in the aforementioned procedure was replaced by 2‐hydroxy‐4‐methoxybenzaldhyde. fCNT3 and fCNT4 was synthesized by using modified Paiva et al ., procedure by reacting Z‐gly‐OH (0.502 g) with 2‐ethylbutyraldehyde (1.5 ml) and octanal (1.9 ml), respectively.…”

One-dimensional nitrogen-containing carbon nanostructures

“…Amino groups were covalently attached to the sidewall of SWCNTs via thermal aziridination [303]. The solvent-free, onepot functionalization of MWCNTs based on the 1,3-dipolar cycloaddition of azomethine ylides, using N-benzyloxycarbonyl glycine and formaldehyde, has led to MWNCNTs [304]. The formation of cyclic benzyl carbamate and pyrrolidine functional groups on MWNCNTs surfaces was evidenced by XPS.…”

Multiscale carbon fibre–reinforced polymer (CFRP) composites containing carbon nanotubes with tailored interfaces

“…After carrying out DCA reaction, an additional peak at approximately 400.8 eV emerges and it is related to the formation of a considerable amount of nitrogen‐containing groups (3.3 at%; Table ). The survey spectra of f ‐MWCNTs also revealed the presence of oxygen‐containing groups onto the MWCNT surface due to the formation of benzyl carbamate (1.9 at%; Table ) . A small amount of aluminium was found as a contamination from p ‐MWCNT production process (Al2p at 74.3 eV).…”

“…Mild reaction conditions were used to avoid severe nanotube breakage or damage. The relative concentration of the two major products generated—pyrrolidine and benzyl carbamate—is strongly dependent on the reaction temperature and time . Thus, to ensure a higher loading of the nucleophilic group (pyrrolidine) that can further react with the epoxy molecules, the functionalization was carried out at 250°C for 3 hours (Figure ).…”