Dielectric Relaxation and Alternating-Current Conductivity of Highly Crystalline Poly (ethylene-2,6-naphthalenedicarboxylate) Films
The dielectric relaxation and alternating-current (AC) conductivity behavior of poly(ethylene-2,6-naphthalenedicarboxylate) are found to be sensitive to its degree of crystallinity. It has been shown that increasing the temperature at low frequency leads to three relaxation phenomena due to different molecular motions: the β, β*, and α relaxation. The effects of the chemical and morphological structure of the material on the dielectric properties were also considered. AC conductivity measurements were performed and studied according to the "universal" Jonscher power law. This universal law allows satisfactory determination of the parameters A and n, which seem to be correlated via a mathematical relationship, reaching an optimum due to the β relaxation of the chain branching.