CHARACTERIZATION OF CARBOXYL AND PHENOL GROUPS IN KRAFT PULPS AT DIFFERENT TEMPERATURES

摘要

Carboxyl and phenol groups in pulps have been studied at different temperatures (25, 45, 65 and 85 deg C) by potentiometric titration. The method developed allows determination of both the protonation constants and the concentrations (capacities) of the acid groups. Samples of unbleached and oxygen bleached softwood kraft pulps were analyzed. Models with either one or two carboxyl groups and one phenol group were applied to evaluate the titration data. The temperature was found to have a remarkable influence on the concentration of available phenol groups.