Electromagnetic Microwave Absorption Performances of Aminated Carbon Fibers

Microwave Properties of Composite Films Based on Polyvinyl Chloride and Brominated Activated Carbon

“…During bromination, up to 6 wt % of bromine was incorporated into AC. In addition, AC/Br 2 shows a 2‐fold increase in oxygen concentration, indicating parallel oxidation of the carbon surface and the formation of various oxygen‐containing groups [26] . The structure of the apricot pits, from which the AC was derived, is shown in the SEM micrographs (Figures 1a, b).…”

“…However, the AC/Br 2 sample shows a slightly lower thermal stability. Both the AC and AC/Br 2 samples contained a significant amount of water, as evidenced by the large weight loss when heated to 130 °C [26] . The AC/Br 2 sample contained 6 % more water than the AC sample.…”

“…The AC/Br 2 sample contained 6 % more water than the AC sample. Further heating to ∼520 °C results in a weight loss of 5–9 %, which is probably due to the decomposition of thermally unstable oxygen‐containing groups, such as carboxylic, anhydride, and lactone groups [26,27] . The weight loss of AC/Br 2 was greater at below 520 °C because the constitutional bromine was detached, hydrogenated, and thermodesorbed in the form of HBr, whereas AC contains no bromine.…”

“…The microwave reflection loss (S 11 ) and microwave transmission loss (S 21 ) of the films were measured in the Ka-band frequency range using a network analyzer. [25] Optical images were obtained using a Zeiss LSM 800 confocal microscope.…”

“…Liquid phase bromination is the simplest and most effective method of modifying the carbon surface, and it can probably impart good thermal stability to the carbon surface, making porous carbon materials suitable for use in environments where heating to moderate temperatures may occur. Our previous studies [25] have shown that the bromination of porous carbon structures significantly affects their microwave properties. For this reason, it makes sense to use various brominated carbon solids as fillers (in composites) with potentially tunable properties.…”