Dielectric Properties in Polyamides of m-Xylylenediamine and Dicarboxylic Acids

概要

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Dielectric properties were investigated for polyamides consisting of m-xylylenediamine and aliphatic dicarboxylic acids with the number of carbon atoms from 6 to 11, over a frequency range of 25 Hz to 1 MHz, at temperatures from 200 to 400 K. The α relaxation with a relaxation strength of 60 to 80 was observed at temperatures above the glass transition temperature T_g in quenched amorphous samples and was related to the micro-Brownian motion of the molecular chains of these aromatic polyamides. The dipole moment per repeating unit was 9 to 11 D for the α relaxation. The β relaxation observed at temperatures below room temperature exhibited a small relaxation strength, which was attributed to the motion of carbonyl groups with water molecules bound by a hydrogen bond. The space-charge polarization effects took place at high temperatures and low frequencies. The crystallization occurring during the heating process decreased the dielectric constant and loss in the α relaxation and the space-charge polarization.
社団法人応用物理学会の論文
1999-09-15