Eight amorphous, thermoplastic aromatic poly(ether)s and poly(ether ketone)s, some containing fluorine, were investigated by dielectric relaxation spectroscopy over the frequency range 20–10 5 Hz and the temperature range ¹130–300°C. For the polymers containing perfluorophenylene units, three relation processes were observed; one corresponding to the glass transition (a-relaxation), and a further two subT g secondary process (b- and g-processes). For polymers without perfluorophenylene units, a b-process was not detected. The sub-T g transitions followed Arrhenius behaviour and were sensitive to polymer structure and chain flexibility. The sub-ambient relaxation exhibited a strong dependence on absorbed moisture. The polymers containing perfluorophenylene units showed a significant decrease in dielectric permittivity at 100 kHz and this was attributed mainly to a reduced electronic polarisability. The a-relaxation strength of the perfluorinated polymers, which arises from dipolar motions, was also reduced.
Посилання на статтю:
Dielectric relaxation behaviour of fluorinated aromatic poly(ether)s and poly(ether ketone)s / A.A. Goodwin, J.R. Atkinson, J.N. Hay, F.W. Mercer // Polymer. – 1999. – N 40. – P. 1515–1524.