On the deformation induced order–disorder transitions in the crystalline phase of polyamide 6

The present paper deals with the mechanically induced structural changes in polyamide 6 with initial α or γ crystal phases. By combining Wide Angle X-ray Scattering with FTIR spectroscopy measurements, order–disorder transitions have been clearly evidenced at 70 °C in both cases. The origin of this phenomenon is ascribed to structural defects involved in plastic deformation. By contrast, at 150 °C, no major transformation is revealed in α phase, whereas when starting from γ crystals, a γ−α transition is clearly evidenced. The central role of intracrystalline molecular mobilities is pointed out to account for the observed behaviours as a function of temperature.