Structural analysis of PVC and PFA carbons prepared at 500-1000 °C based on elemental composition, XRD, and HRTEM

Temperature programmed oxidation (TPO) method to evaluate the structure of carbonaceous materials was proposed in the previous paper, and this method was applied to analyze two sets of carbons derived from PVC and PFA in the temperature range of 500-1000 degreesC. Amounts of H2O, CO and CO2 evolved during oxidation were accurately determined, and they were used to estimate an average size of polyaromatic graphene sheet in PVC and PFA carbons. The size increases with preparation temperature for both series of carbon. The estimated size was compared with those determined by XRD and TEM methods. The size determined by TPO method was much larger than the size determined by XRD and TEM. Each method provides completely different information, which naturally leads to different sizes. Combination of these three methods is quite useful to understand carbon structure. The most remarkable difference between two sets of carbon was the degree of stacking rather than size of graphene sheet. This difference seems to control the reactivity of these two carbons during TPO. (C) 2004 Elsevier Ltd. All rights reserved.