Intensity of sulfonitric treatment on multiwall carbon nanotubes

Abstract

We present a study of sulfonitric treatment and its effect on MWCNTs at different temperatures (90, 110, 130 and 150°C) using DRX, XPS, FTIR, Raman spectroscopy, TEM and zeta potential. It was found that oxidation starts with the C-C and C-H bonds generating different oxidized groups from alcohol to carboxylic acid, following a sequential oxidation. Given that heterocoagulation needs a maximum zeta potential gap between the ceramic and the MWCNT surface and it significantly exist a risk of manipulate acids at high temperature it is recommended to use acid treatment of CNT at 110°C for generating ceramic composites by heterocoagulation.

Heterocoagulation and SPS sintering of sulfonitric-treated CNT and 8YZ nanopowders

“…This was not observed in the 8YZ-CNT90 and 8YZ-CNT130 materials ( Figure 5(c, e), respectively) possibly due to the fact that acidic pretreatment at 50ºC is less effective for these mixtures. This observation might be explained by lower functionalization and defect formation during this pretreatment [24,25]. On the other hand, the other two pretreatments (at higher temperatures: 90ºC and 130ºC) displayed better homogenization during the heterocoagulation processes.…”

“…The characterization of acid-treated CNTs at different temperatures was previously reported [24]. The objective of this study was to develop materials based on 8YZ + 1 wt% CNT by the electrostatic heterocoagulation processing method and to study the influence of the surface treatment temperature of the CNT on the final textural properties of ceramics.…”

“…With this method oxidized groups are formed on the CNT surfaces to produce negative charges and thus allow successful heterocoagulation. There are several variables in the functionalization of CNTs that can affect the result of this surface modification, including the duration of treatment [22], concentration and type of acid [23] and temperature [24].…”

“…In two recent articles [24,25], we reported a systematic study of the surface modification of multiwall CNTs by sulfonitric acid exploring both the temperature and time as processing variables. Sulfonitric treatment was selected for the present study due to its known strong oxidizing capabilities, the treatment time was fixed at 20 min, based on bibliographic data, and the variable parameter was the treatment temperature.…”

A Novel Basalt Flake Epoxy Resin Coating Modified by Carbon Nanotubes

“…The acid treatment can open five or seven-membered ring defects at the ports and introduce functional groups such as carboxyl (-COOH) and hydroxyl (-OH) into the surface of CNTs ports and sidewalls, which is conducive to its subsequent reaction [17]. It can be seen from Figure 1 that the peak strength of acidified CNTs was enhanced near 3490 cm −1 compared with the initial CNTs, which was induced by the stretching vibration of -OH caused by the presence of carboxyl group or water adsorbed on the surface [18]. The characteristic absorption peaks appeared at 1750-1400 and 2916 cm −1 were due to the carboxyl C=O stretching vibration and the C-H stretching vibration, respectively [19,20].…”