Oxygen plasma modification of pitch-based isotropic carbon fibres

Abstract

International audienceAn isotropic carbon fibre was surface-treated by microwave oxygen plasma at different conditions and characterised by scanning electron microscopy (SEM), scanning tunneling microscopy (STM), N2/CO2 adsorption, Raman spectrometry, X-ray photoelectron spectroscopy (XPS) and temperature-programmed desorption (TPD). It is shown that the structure of the fibre suffers only limited alterations upon plasma treatment in such a way that the local disorder on its surface, which was already large in the fresh material, barely increases after the plasma exposure, as detected by Raman measurements. At the nanometre scale, STM images revealed a moderate increase in surface roughness. Evidence for chemical changes undergone by the fibre following the etching was provided by XPS and TPD, showing that stable oxygen functionalities were introduced by the plasma exposure, a result of practical importance for the application of this treatment not only to this type of carbon fibre, but to carbon materials in general. It was also observed that very gentle plasma exposures were generally sufficient to provide the fibre surface with a large amount of oxygen functional groups and that more intense treatments had a negative effect in this respect (i.e. they were not able to supply oxygen to the surface in larger amounts than the softer treatments did)

Functionalization and Characterization of MWCNT Produced by Different Methods

“…Surface modification imparts various functional groups, such as hydroxyl, carboxyl, amine and vynil, and their adsorption onto CNTs surface is responsible for the various physicochemical and catalytic properties of the modified material. These oxygen containing functional groups can be introduced by mechanical [26], chemical [27] and electrochemical techniques [28]. The amount and type of attached functional groups strongly depends on the type of surface modification applied.…”

Microwave plasma assisted preparation of Pd-nanoparticles with controlled dispersion on woven activated carbon fibres

“…Thus, Boudou et al [15] confirmed by SEM and STM analysis that the pitch-based carbon fibres treated in low pressure (1.0 mbar) oxygen MW plasma during 1-5 min keep their structure and diameter. At the same time, the carbon surface is cleaned from contaminations and the specific surface area (SSA) is increased due to improved roughness.…”

“…For example, oxygen or air plasma leads to the oxidation of carbon surface [15][16][17][18][19][20][21][22][23][24][25][26][27]. Nitrogen and ammonia plasmas introduce C/N functionality on carbon surface [26][27][28].…”

“…Moreover, it is possible to obtain different surface effects by varying the plasma parameters (power, treatment time, and gas pressure) without changing the gas. For example, oxygen or air MW-plasma creates on the carbon surface oxygen containing groups under low power treatment within short time [15,26,27], but cleans the surface with the partial elimination of the oxygen functionality under high power MW radiation during long exposures [15,22].…”

Flexural strength and tribological properties of rare earth treated short carbon fiber/polyimide composites

“…The mechanical interlocking provided a strong interface bonding even though other effects were relatively weak [15]. In addition, the enhancement of the surface roughness reduced the contact angle between fibers and PI and hence increased the wettability [16].…”