Steam explosion pulps were studied by means of CP/MAS <sup>13</sup>C NMR spectroscopy. The steam explosion treatment of aspen chips with Na<sub>2</sub>SO<sub>3</sub> and Na<sub>2</sub>SO<sub>3</sub> + NaOH led to a loss in hemicellulose and an increase in cellulose crystallinity. No lignin dissolution occurred during explosion pulping, although the lignin structure might have changed to a certain extent. For comparison purposes, conventional CMP and CTMP pulps were also analyzed. The conventional treatments revealed less modification in the spectrum with regard to original wood samples.
X. Hua, G. Capretti, B. Focher, A. Marzetti, B. V. Kokta, and S. Kaliaguine, "Characterization of Aspen Explosion Pulp by CP/MAS 13C NMR," Appl. Spectrosc. 47, 1693-1695 (1993)