Polymer-solvent effects in cellulose urethane and methyl cellulose urethane solutions

The polymer-solvent interaction was studied for two similar cellulose derivatives in the semi-dilute concentration range by static and dynamic light scattering. The trisubstituted 3-chlorophenyl carbamate (3Cl-CTC) and a mixed trisubstituted derivative with methyl groups (degree of methyl substituents: DS _Me = 1.6–1.7)combined with the abovementioned 3-chlorophenyl carbamate groups filling the still open positions at the cellulose backbone were synthesized, fractionated and characterized according to standard methods. Different kinds of associations, entangled clusters with a rod-like shape on one side and entanglement networks on the other side, exist in semi-dilute dioxane solutions caused by different polymer-solvent interactions. These quite different associations lead to either a liquid crystalline or a gel-like state upon increase of concentration.