Characterization of aspen explosion pulp by CP/MAS 13C NMR

Steam explosion pulps were studied by means of CP/MAS 13C NMR spectroscopy. The steam explosion treatment of aspen chips with Na2SO3 and Na2SO3 + 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.