Diffusion and solubility of n-alkanes in polyolefines

The diffusion and partition coefficients (relative solubility constants) of n-alkanes (from carbon nos. 12-32) have been determined by a permeation method (pouch method) for the polyolefines LDPE, HDPE, and PP-copolymer, and PP-homopolymer at room temperature. The activation energies for the diffusion are interpreted in the meaning of the rate transition theory. Correlations exist between the activation energy delta E and the heat of vapourization delta vH, as well as between the activation energy delta E and the Arrhenius preexponential factors D0. These correlations are useful for the prediction of the diffusion coefficients of n-alkanes with carbon numbers lager than 32.