FLOW BIREFRINGENCE AND OPTICAL ANISOTROPY OF THE MOLECULES OF CYANOETHYLATED CELLULOSE ESTERS

Dynamics of partly permeable chitosan chains in acetic acid solutions was studied by the flow birefringence technique in longitudinal and sh ear flows. Chitosan macromolecules transform into an almost completely uncoiled state on exposure to a strong longitudinal hydrodynamic fiel d. An increase in the concentration and/or a decrease in the ionic str ength of the chitosan solution lead to a growth of the effective defor mation relaxation time of the whole chain, and shift the transition to ward lower deformation rates. There is a good agreement between the ch ain relaxation times obtained by the FBR technique for the shear and l ongitudinal flows.