Secondary transitions of aryl-aliphatic polyamides III. H-2 NMR investigation

H-2 NMR experiments were performed on a selectively deuterated aryl-aliphat ic copolyamide in order to investigate the local dynamics of the phenyl rin gs as a function of temperature. The activation energy of the phenyl ring f lip motion, determined from the H-2 NMR experiments, was shown to be identi cal to the activation energy determined by dielectric relaxation for the be ta transition. Such a result tends to indicate that the phenyl ring flips a re part of the beta transition in the aryl-aliphatic copolyamide under stud y. (C) 2000 Elsevier Science Ltd. All rights reserved.