Dilute solution viscometry study on the miscibility of N,O-carboxymethyl chitosan-cellulose acetate blends

Abstract

Dilute solution viscometry method is used for studying viscosity behavior of newly prepared N,O-carboxymethyl chitosan (NOCC), cellulose acetate (CA), and their blends at different compositions (0/10, 2/8, 4/6, 5/5, 6/4, 8/2, 10/0). In this method, reduced viscosity (η_sp/c) and inherent viscosity (ln η_rel/c) of the given polymer sample have been determined by measuring the flow time of the polymer sample in acetone solvent. Huggins (k) and Kraemer coefficients (k′) for given polymer-solvent system are calculated from the extrapolation of plots (η_sp/c) versus(c) and (ln η_rel/c) versus(c). The miscibility of this polymer system is determined using different criteria such as Δb, Δb′, , interaction parameter Δ[η], thermodynamic parameter α, and modified thermodynamic parameter β. Based on the positive or negative sign of this criteria, miscibility of the polymer system is investigated. The results of the dilute solution viscometry method suggested that the NOCC/CA blends are miscible at the compositions range of 4/6, 5/5, 6/4, and 8/2 and completely immiscible at the 2/8 composition. The results are also supported by Fourier transform infrared analyses of all the compositions.