Evaluation of the viscometric constants for chitosan

Viscosity‐average relative molecular masses have been determined for a series of chitosans having the same relative molecular mass and relative molecular mass distribution but differing extents of N‐acetylation. The results obtained show that the same viscometric constants in the Mark‐Houwink equation [η] = Km ·Ma are applicable to chitosans over the range between 0 and 40% N‐acetylation Comparison of literature values for number‐ and weight‐avepge rela‐tive molecular masses Mn, and Mw, with the viscosity‐average relative molecular mass M, values calculated using the related viscosity data and each of the three sets of viscometric constants that have been proposed for chitosan, confirms that the most accurate values currently available are km = 1,81 · cm−3 · 10−1 and a = 0,93, using 0,l M acetic acid/0,2M NaCl as solvent.