The Measurement of Self-Diffusion in Solid Polymers

Abstract

The self‐diffusion constant of the macromolecules in plasticized polystyrene and pure poly‐n‐butyl acrylate has been measured over a wide variety of conditions by a radioactive tracer technique. Well‐characterized polymer fractions were used throughout. Simultaneous measurements of the bulk viscosity were also made. From the data obtained one is able to show that within experimental error the product of the self‐diffusion constant and the bulk viscosity is equal to a constant. This constant has been predicted by theory, and the agreement with the experimental value is good. Therefore, it appears possible to obtain diffusion constants directly from bulk viscosity data.