Diffusion of thiodipropionic esters and hydroxybenzophenones in isotactic polypropylene

Abstract

The diffusion of members of two series of organic compounds in the liquid state in isotactic polypropylene has been studied between 80–110°. The substances examined were: dimethyl 3, 3′-thiodipropanoate; di- n-hexyl 3, 3′-thiodipropanoate, di- n-dodecyl 3, 3′-thiodipropanoate, di- n-hexadecyl 3, 3′-thiodipropanoate; 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4- n-butoxybenzophenone, 2-hydroxy-4- n-octoxybenzophenone, 2-hydroxy-4- n-dodecoxybenzophenone, 2-hydroxy-4- n-octadecoxybenzophenone. The diffusion coefficients are reported. A linear dependence of the logarithm of the frequency factor D 0 and of activation energy E 4 upon the number of carbon atoms present in the alcoholic radical was found. The experimental data suggest that the mechanism of the diffusion of large molecules in crystalline polymers is analogous to that assumed for small molecules in amorphous polymers.