Dielectric spectroscopic results and chemical accessibility of sulfite pulps

The relation between the chemical reactivity of a dissolving pulp and the m olecular mobility of cellulose was investigated by an unconventional method for these problems: dielectric relaxation spectroscopy (DRS). Carefully dr ied pulps show better reactivity in comparison to a mill dried sample. A sp ecific deformation of the local polymeric backbone dynamics (beta -relaxati on) was observed in the former samples. The intensity of the dielectric bet a- relaxation correlates with the acetylation velocity in an excellent mann er. A similar correlation was found between the relaxation strength and the water retention capacity of pulp. All experimental results support the exp lanation that hydroxyl groups of those anhydroglucose units which contribut e to the low frequency unstructured underground relaxation (here named delt a -relaxation) outside of the real beta -peak in the dielectric spectrum ar e preferably substituted. The results of the investigation indicate that di electric spectroscopy can provide can provide a new, additional, alternativ e tool to characterize the accessibility and chemical reactivity of cellulo se.