Quantitative evaluation of rate-determining steps in polymer complexation

A quantitative method to find the rate determining steps in the ion-adsorption kinetics of polymer complexation agents is theoretically formulated and experimentally established. The degree of film-diffusion control and particle-diffusion control is simultaneously evaluated based on the law of addition of kinetic resistances combined with Einstein's viscosity expression. The change in the initial rate with respect to the resin concentration was scrutinized by plotting the effective rate constant versus the initial rate, and the film mass transfer coefficient was calculated. This is a concise and practical procedure to analyze the rate determining steps of polymer complexation kinetics. The validity of the method was confirmed by studying the adsorption of Cu(II) ion on crosslinked chitosans. In these materials, the importance of film diffusion was found both in adsorption and desorption processes. (C) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44738.