Diffusion Coefficients of Additives in Polymers. I. Corrélation with Géométrie Parameters i

Diffusion coefficients of a broad range of molécules with molecular weight ranging from 100 to 800 g/mol hâve been measured in polypropylene, by solid/solid contact methods (without liquid contact), at 40°C. The behaviors of thé différent molécules are compared to those of linear alkanes. The diffusion coefficients are correlated to parameters describing size, shape, and flexibility of thé molécules. The concept of weighted fractionated volume is introduced using molecular modeling. It enables thé classification of thé molécules according to modes of molécule displacement (crawling, jumps, or dual mode). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2422-2433, 2001