STUDY OF MOLECULAR MOBILITY AT THE SECONDARY RELAXATIONS RANGE IN POLYAMIDE-66 AND POLYAMIDE-66 EPR BLENDS BY THERMALLY STIMULATED CREEP AND CURRENT/

Thermally stimulated creep with fractional loading technique and therm ally stimulated current have been used to investigate the relaxation p rocesses of polyamide 66 and polyamide 66/EPR blends over temperature range covering gamma, beta and alpha(EPR). Absorbed water decreases th e thermally stimulated creep and the thermally stimulated current heig ht of gamma-relaxation. The thermally stimulated creep mechanical beta -relaxation in PA66 is characterized by a broad peak, while the therma lly stimulated current dielectric one is composed of two separate proc esses beta(1) and beta(2) according to the maximum temperature decreas e. The peak height of the beta(1) component is increased by moisture w hile the beta(2) component is not modified. According to the criteria of Starkweather for sample and complex relaxations, the gamma- and low temperature part of beta-relaxations have been assigned to localized non-cooperative motions. The high temperature part of beta-process and alpha(EPR)-relaxation have positive activation entropies and result f rom high cooperative motions. These interpretations from thermal sampl ing analysis is in close agreement with the predictions of Ngai's coup ling model.