Effect on oxygen permeation properties of amorphous polyamides

The structure of an amorphous polyamide prepared from hexamethylenediamine and isophthalic/tere-phthalic acids was modified in order to determine the effect of chemical structure on the oxygen permeation properties. The greatest increase in permeation was obtained by lengthening the aliphatic chain. Placement of substituents on the polymer chain also led to increased permeation. Reversal of the amide linkage direction had no effect on the permeation properties. Free volume calculations and dielectric relaxation studies indicate that free volume is probably the dominant factor in determining the permeation properties of these polymers. 

Through systematic modification of the polymer backbone, the effects of chemical structure upon the oxygen permeation properties of aliphatic-aromatic amorphous polyamides were determined. In this class of polymers, the greatest effects were obtained by alteration of the chain length and disruption of the amide hydrogen bonding by N-alkylation. It is remarkable that reversal of the amide linkage has no effect whatsoever on the permeation properties of the examples studied. 

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See also in sourсe #XX -- [ , , ]

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