STUDIES OF LIQUID-INDUCED CRYSTALLIZATION OF BISPHENOL-A POLYCARBONATE

The course of liquid‐induced crystallization of a bisphenol A‐derived polycarbonate was investigated using acetone, methyl propyl ketone, methyl isobutyl ketone, and xylene as swelling agents. It was found that above a certain temperature, characteristic of a given polycarbonate–swelling agent system, the diffusion process takes place with the formation of a sharp boundary. The velocity of motion of the diffusion front was determined at various temperatures, and these data were then used to calculate the apparent diffusion coefficients and diffusion activation energies for the different swelling liquids employed. Moreover, a distinct separation of the diffusion and crystallization fronts was observed in the systems investigated, changes in the distance between these two fronts having been determined for various swelling temperatures. The above phenomenon was used to determine the experimental conditions making possible the characterization of a crystallization process not controlled by the diffusion of the swelling agent into the sample. The dependence of half‐times of crystallization on temperature was determined based on crystallization kinetics studies performed by means of a light depolarization technique. Copyright © 1979 John Wiley & Sons, Inc.