A Scalable Route to Highly Functionalized Multi‐Walled Carbon Nanotubes on a Large Scale

Abstract

A scalable and solvent‐free chemical process to obtain highly functionalized and dispersible multi‐walled carbon nanotubes is reported. Highly functionalized multi‐walled carbon nanotubes have been prepared using in situ generated aryl diazonium salts in the presence of ammonium persulfate and 2,2′‐azoisobutyronitrile by solvent‐free techniques. In the Raman spectra of the resulting materials, characteristic peaks, the D‐ and G‐bands, are shifted by about 10 cm−1 to lower frequencies. At the same time, the relative intensity ratios between the D‐ and G‐bands increase in comparison to that in the spectrum of the purified product. Fourier‐transform infrared spectroscopy reveals the presence of the functional groups on the surface. Transmission electron microscopy images directly confirm the significant build‐up of sidewall organic moieties on the treated materials. The weight loss of various functional moieties determined by thermogravimetry–differential scanning calorimetry analysis is about 18–33%. The dispersibility of the functionalized materials in solvents, such as chloroform, tetrahydrofuran, and water, is obviously improved.magnified image

Nitrophenyl functionalization of carbon nanotubes and its effect on properties of MWCNT/LCP composites

“…The D-band around 1320 cm -1 was related to local defects that originated from the structural imperfections and associated with the disordered sp 3 hybridized carbon network. 10,22,25 The peak intensity ratio (I D /I G ) of the raw MWCNTs was 1.1 which was lower compared to 1.39 of MWCNT-C 6 H 4 NO 2 . This result indicates that some of the sp 2 C atoms (C=C) were converted to sp 3 C atoms (C-C) at the surface of the MWCNTs after the chemical functionalization.…”

“…Compared to raw MWCNTs, the functionalized MWCNTs showed strong characteristic bands at 1340 and 1530 cm -1 , corresponding to the stretching of aromatic nitro groups. 22 In addition to these peaks, two other new peaks at 1180 and 1130 cm -1 were due to the C-O stretching and out of plane deformation. 22 These results suggested that the aromatic nitro groups have been covalently attached onto the MWCNTs.…”

“…22 In addition to these peaks, two other new peaks at 1180 and 1130 cm -1 were due to the C-O stretching and out of plane deformation. 22 These results suggested that the aromatic nitro groups have been covalently attached onto the MWCNTs. The XPS results showed that the relative atomic concentrations of carbon and oxygen were 97.82% and 2.08% for raw MWCNTs, whereas after functionalization, the C, O and N contents of aromatic nitro-modified MWCNTs are 87.06%, 8.82% and 4.12%, respectively.…”

“…Synthesis of MWCNT-C 6 H 4 NO 2 (Scheme I) was followed according to the previous report. [22][23][24] In details, 240 mg of MWCNTs (20 mmol) was put into a 500 mL dry flask. 20 mL of concentrated H 2 SO 4 and 20 g of ammonium persulfate (87.6 mmol) were added to the flask and the mixture was sonicated for 30 minutes.…”

Preparation, characterization and properties of polycaprolactone diol-functionalized multi-walled carbon nanotube/thermoplastic polyurethane composite

“…After acid treatment, one obvious peak at 3434 cm -1 could be observed, and it was associated with the OAH stretching of carboxylic acid group. Besides, the two band at approximate 1360 cm -1 corresponded to disorder mode (D-band), which was associated with surface defects of MWCNTs [30]. The functionalization degree of MWCNTs can be measured by the intensity ratio of the D-band and G-band (I D /I G ) [31].…”