Structure evolution of woodceramics by X-ray diffraction and Raman spectroscopy

The laser Raman spectroscopy and X-ray diffraction (XRD) techniques were applied to investigate the structure of woodceramics (WCS) from carbonizing tobacco stems and phenolic resin at different carbonization temperatures up to 1773K. Experimental results show WCS are non-graphitic carbon consisting of tobacco stems-originated amorphous carbon reinforced by glasslike carbon generated from phenolic resin. With the increase of carbonization temperature, the number of diffraction peaks is increasing, but the interlayer spacing of graphene sheets, d(002), is decreasing. As carbonization temperature increased above 973K, the turbostratic crystallites grew very little, but the graphene sheets grew substantially from 2.7 to 5.6nm by Scherrer equation. The Raman spectra of WCS show the known D band which is related to disorder carbon and G band which corresponds to graphite with varying characteristics that are similar to other graphitoidal materials. The integrated intensity ratio R = I-D/I-G(R-value) which is the degree of disorder of WCS is decreasing with the increase of carbonization temperature above 973K. And the trend of La calculated by using the Tuinstra-Koening empirical relation is opposite but is consistent by Scherrer equation of XRD technique. The obtained results also indicate that 973K is the turning point temperature for preparation of WCS and the Raman spectroscopy will become a quick method for the structure analysis of WCS.