The dielectric properties of polyamide-4,6 were examined as functions of frequency, temperature and moisture content. The dielectric spectra were compared with the results of dynamic mechanical measurements in torsion at 0.2153 Hz, as a function of temperature, and with the dynamic dielectric properties of commercial polyamide-6,6. Three relaxation processes are observed in polyamide-4,6, which are related to either local or collective molecular mechanisms of motion, similar to the relaxation processes observed in other polyamides. At temperatures above the glass transition temperature, ionic conductivity is observed, which, due to the semicrystalline structure of the material, gives rise to a strong Maxwell-Wagner-Sillars (MWS) polarization. With increasing temperature, the conductivity increases sharply, eventually causing electrode polarization, and thus obscuring the dielectric effects in the material. All loss processes shift to lower temperatures with increasing water content. The activation energies of the secondary relaxations decrease with increasing water uptake, while the fl and ct relaxations are enhanced in magnitude.
Посилання на статтю:
Dielectric properties of polyamide-4,6 / P. A. M. Steeman* and F. H. J. Maurer // Polymer. – 1992. – Vol 33. – P. 4236-4241.