Relaxation phenomena in the polyamidoesters: Block copolymers of dodecalactam with oligotetramethylene glycol

Relaxation effects in the copolymers of dedecalactam with oligotetramethylene glycol have been investigated by a dielectric method. The dielectric constant and dielectric loss were determined in the frequency range 10 Hz-1 MHz over the temperature range 120–300°. The dodecalactam content was varied from 100 down to 19 mol%. Two relaxation regions were found: a high-temperature region (α) associated with segmental mobility (glass-transition) and a low-temperature one (β) relating to local mobility in the copolymers. The glass-transition temperatures were determined as well as the activation energies and the relaxation time distribution parameters, and the dipole moment of the polydodecalactam repeat-unit was calculated. The glass transition temperature and the dielectric relaxation intensity (increase in the dielectric constant) decrease linearly as the amount of polyester fragments increases.