The study of dipolar and space charges in semicrystalline polymers

The contribution of dipolar and space charge to the released current for two polar semicrystalline polymers, in a temperature range including the glass-rubber transition temperature T-g, is analysed. Both types of charge are present for a wide range of polarization conditions. The space charge is captured in deeper traps and consequently is more stable. The activation energy continuously increases as the temperature increases and a compensation behavior was observed. While the alpha peak is centred around T-g the position and magnitude of the space charge peak changes significantly with polarization conditions. There is a narrow distribution of the relaxation parameters. For Nylon I I samples a pyroelectric behavior was observed.