γ-irradiation effect on the chain segment motion and the charge storage for nylon 6 films

γ-irradiation effect on the relationship among the chain segment motion, the charge storage and supermolecular structure for nylon 6 has been investigated by the measurements of thermally stimulated depolarization current (TSDC), viscosity and wide-angle X-ray diffraction (WAXD). There are three current peaks (α, ρ₁ and ρ₂ peaks) in the TSDC spectra above room temperature. The α peak is attributed to dipolar relaxation by the motion of chain segments, and the ρ₁ and ρ₂ peaks are originated from the space charge relaxation. By analyzing the characteristic parameters of these relaxation peaks, it is found that the γ-irradiation induces the decrease of the magnitude of intra- and inter-molecular mobility, and also induces the increase of the space charge density and the trap depth, especially that for ρ₂ peak. The restriction of molecular movement can be explained by an increase of molecular chain cross-linking in the film. The results show that some structure defects are formed during the γ-irradiation.