Vitro Carbon made from Acetone-Furfural Resin

II-X-ray Diffraction and ESR of Vitro Carbon

Abstract

The X-ray analysis shows that Vitro Carbon is a typical non-graphitizing carbon. The crystallite spacing, d ₍₀₀₂₎ and d ₍₁₁₀₎ , the crystallite thickness, J.c ₍₁₁₀₎ and the crystallite size, I, a ₍₁₁₀₎ change stepwisely with heat treatment temperature (HTT). The value of La ₍₁₁₀₎ is almost constant over the range of HTT about 1000-1500°C, increases with HT over the HTT range of about 1500-2000°C, is almost constant again over the HTT range of about 2000-2500°C, and increases suddenly with HT above about 2500°C.
The ESR signal for Vitro Carbons in vacuum shows the presence of a new narrow component and a broad component in the HTT range about 2000-2600°C. The g-value for the narrow component is almost equal to that of free spin all over the HTT range but the g-value for the broad component is different from that of free spin above HTT about 2500°C. The ESR signal of Vitro Carbons in the HTT range of about 500-1000°C is oxygen sensitive and that of Vitro Carbons in the HTT range of about 1300-1800°C and HTT 3000°C is oxygen insensitive. In the HTT range of about 2000-2600°C, the narrow component is oxygen sensitive and the broad component is oxygen insensitive. Therefore, it seems that the narrow component is attributable to the localized spin centers produced by the edge defects of graphite layers having three-dimensional twisted stacking, and that the broad component is attributable to the unlocalized spin centers originated in the charge carriers.