Differences in molecular properties of celluloses from different biological origins were investigated chiefly in terms of the rheological properties of their solutions in 8 wt % LiCl/
N,
N-dimethylacetamide (DMAc). Cotton linter (CC) and dissolving pulp (DP) were used as cellulose samples derived from plant, and a cellulose from
Acetobacter xylinum was also used as a bacterial cellulose (BC). For the three kinds of cellulose solutions, the values of η
0 − η
s (η
0: zero shear rate viscosity of solution, η
s: solvent viscosity) were in proportion to the weight fraction of polymer, φ
w, in the dilute region. On the other hand, they were in proportion to φ
w4 for the CC and the DP solutions and φ
w3 for the BC solution in the semidilute or concentrated region. This φ
w-dependence of η
0 − η
s shows that CC and DP, celluloses from plants, behave as a flexible polymer and that BC behaves as a rodlike polymer, according to several molecular theories. Plateau modulus,
GN, was in proportion to φ
w2 for the CC solution, signifying that network structure by entanglement was formed in the CC solution, as is often observed for solutions of flexible synthetic polymers. On the other hand, the concentrated solution of BC showed the typical small-angle X-ray scattering (SAXS) profile of two-phase systems, which can be well approximated by Debye-Bueche equation. This fact indicates that the structure of the BC solution apparently differs from the network structure.
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