Multipie relaxations in ultem-polyetherimide

The various dielelectric relaxation processes responsible for charging and discharging mechanisms in Ultem film have been investigated using the thermally stimulated discharge(TSD) technique. Ultem is a polyetherimide based on regular repeating units of ether and imide linkages. Samples of the size 3 cm² were polarized at different polarizing temperatures (130–22G°C) and electric fields (120 kV/cm to 240 kV/cm). TSD currents were studied from R.T. to 250°C. The T8ûC spectrum is characterized by two peaks which appear around 100 and 200°C, respectively. These are attributed to dipole orientation and motion of space charges, respectively. The observed dependence of the peak temperature as well as the activation energy for various peaks, on polarizing temperature is indicative of a continuous distribution of relaxation times.