Eckelt, J., Knopf, A., Röder, T., Weber, H.K., Sixta, H., Wolf, B.A.

"[h]-M relations for cellulose solutions in either NMMO monohydrate or Cuen"

Journal of Applied Polymer Science 2010, 119, 670-676.

Abstract: The intrinsic viscosities, [h], of nine cellulose samples, with molar masses from 50 × 103 to 1 390 × 103 were determined in the solvents NMMO*H2O (N-methyl morpholin N-oxide hydrate) at 80°C and in cuen (copper II-ethlenediamine) at 25°C. The evaluation of these results with respect to the Kuhn–Mark–Houwink relations shows that the data for NMMO*H2O fall on the usual straight line in the double logarithmic plots only for M = 158 103; the corresponding [h]/M relation reads log ([h]/mL g-1) = –1.465 + 0.735 log M. Beyond that molar mass [h] remains almost constant up to M ˜ 106 and increases again thereafter. In contrast to NMMO*H2O the cellulose solutions in cuen behave normal and the Kuhn–Mark–Houwink relation reads log ([h]/mL g-1) = -1.185 + 0.735 log M. Possible reasons for the dissimilarities of the behavior of cellulose in these two solvents are being discussed. The comparison of three different methods for the determination of [h] from viscosity measurements at different polymer concentrations, c, demonstrates the advantages of plotting the natural logarithm of the relative viscosities as a function of c.

preprint number: 303