Thermally stimulated current study of amorphous oriented PPS

The influence of aging on relaxation phenomena in poly-p-phenylene sulfide (PPS) has been investigated by TSC spectrometry. In the vicinity of the glass transition temperature, T/sub g/, two relaxation peaks have been observed in amorphous oriented PPS: a secondary peak at 62 degrees C in nonaged PPS and at 45 degrees C in aged PPS; and a primary peak at 93 degrees C in both films. According to differential scanning calorimetry data, they have been associated with the dielectric manifestation of the sub-T/sub g/ and T/sub g/ transitions, respectively. Each mode has been characterized by a distribution of relaxation times. For the sub-T/sub g/ mode with the relaxation times follow a Vogel equation while for the T/sub g/ mode they obey a compensation law. The sub-T/sub g/ modes, which is strongly enhanced upon aging, has been attributed to a diffusion of free volume favored by local order in rigid domains. The T/sub g/ mode has been assigned to cooperative movements of sequences of various length in 'true' amorphous regions.<
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