Dynamic mechanical properties of poly(p-phenyleneterephthalamide) fiber



The dynamic mechanical properties of poly(p-phenyleneterephthalamide) fiber were investigated. Measurements of the dynamic mechanical properties were carried out on samples of low crystallinity and low orientation over a temperature range from −100 to +500°C at a frequency of 110 Hz, at a heating rate of 5°C/min. Five relaxation processes were revealed: at −30, 60, 170, 270°C, and in the vicinity of 460°C, respectively. The prominent dispersion peaks located at −30, 60, and 460°C were termed the γ, β, and α relaxations, respectively. The two weak peaks at 170 and 270°C, observed in annealed samples, seem to correspond to the β*-relaxations reported previously by Frosini et al. and Takayanagi et al. The effect of annealing on the behavior of these dispersion peaks was examined, and possible molecular interpretation of these relaxation processes are made.