Structure of chitin-cellulose mixtures in solution and in the solid state

Rheological properties of chitin, cellulose, and their mixtures dissolved i n a common solvent (DMAA with 9% LiCl) were studied ina broad range of comp onent ratios. It was established that mixtures with comparable polymer conc entrations exhibit negative deviations from additivity with respect to visc osity and the activation energy of viscous flow, which is related to a micr oheterogeneity of the system. In the region of mixtures comprising a small additive of one polymer to another, the system is more homogeneous than the solutions of individual polymers. This is confirmed by negative values of the Flory-Huggins parameters calculated from data on the solvent: sorption by the films of one polymer containing 0.5-2.5% the other component. Data o n the D2O sorption by the films of various compositions and on the small-an gle neutron scattering indicate that the structure of composite films with increasing content of the second component changes from homogeneous to micr oheterogeneous.