Influence of Block Molecular Weight on the Dielectric Properties of Segmented Polyamides

Abstract

Dielectric measurements of segmented polyamides consisting of polyether and polyamide structural units have been carried out over a wide range of temperatures and frequencies. The polymers exhibit different peaks - α, β and γ in the log (tan 8) temperature curves. With decreasing hard block molecular weight, the α and β transitions shift to lower temperatures, but the γ transition remains unaltered. The a transition becomes weaker, while the γ transition shifts to higher temperatures when the soft segment molecular weight is increased. The dielectric constant at 100°C at a frequency of 1000 Hz decreases with decreasing hard segment molecular weight. However, the variation of dielectric constant with soft segment molecular weight is irregular. The results of dielectric studies are explained with the help of the segmented structure of the polyether-ester-amides.