Surface characterization and electrical property of carbon fibers modified by air oxidation

Abstract

Polyacrylonitrile-based carbon fibers were modified by oxidation in air, and a systematic study of surface groups and surface resistance at different treated temperatures was made. Progressive fiber weight loss occurred with increasing extents of air oxidation, and it was approximately proportional to the extent of air oxidation from the onset of oxidation up to 400°C. At this point 4.4% of the initial fiber weight had been lost. A faster loss of weight occurred as the extent of air oxidation increased from 400°C to 700°C. X-ray photoelectron spectroscopy studies (C 1s and O 1s) indicated that the oxygen/carbon atomic ratio rose rapidly from 2.64% (as-received carbon fiber) to 42.83% as the oxidation temperature was increased to 400°C. Fourier transform infrared spectra showed the relative intensity of the peaks at about 3440 cm À1 from -OH stretching vibrations and at 1634 cm À1 from -C¼O stretching vibrations increased significantly at 400°C. FESEM micrographs showed that as-received fibers show relatively smooth surface. With oxidation temperature increasing, the fiber surface was rougher. The surface resistance of treated carbon fibers decreased obviously with increasing oxidation temperatures. The most decrease was about 100% at 400°C.

Removal of U(VI) from Aqueous Solution by Amino Functionalized Flake Graphite Prepared by Plasma Treatment

“…Therefore, it can be anticipated that air plasma treatment can lead to microetch formations on FG surfaces. 36 Moreover, the excited species produced during the plasma processing can bring about some changes to the composites surface. 37 Additionally, the effect of grafted functional groups onto FG can be observed from the TEM micrograph of FG.…”

“…This phenomenon obviously indicates that the plasma treatment can have a great impact on the micron scale of the outer surface structure. Therefore, it can be anticipated that air plasma treatment can lead to microetch formations on FG surfaces . Moreover, the excited species produced during the plasma processing can bring about some changes to the composites surface .…”

A Study on Pre-Oxidation of Petroleum Pitch-Based Activated Carbons for Electric Double-Layer Capacitors

“…The XRD patterns of the prepared samples are shown in Figure 2 a. Two broad diffraction peaks were observed at approximately 25° and 43°, corresponding to the C(002) and C(100) planes, respectively [ 45 ]. The C(002) peak of OPP-AC was found to be relatively lower than that of PP-AC, which can be attributed to the disruption of the microcrystalline structure during pre-oxidation, resulting in a reduction of the C(002) peak [ 46 ].…”