Abstract: Variable-temperature X-ray diffraction(XRD) was used to investigate the crystalline transition of Nylon1012 The results show that Nylon1012 undergoes a crystalline relaxation between the glass transition temperature and the melting point. We thus demonstrate, for the first time, the presence of the Brill transition in Nylon1012, a phenomena that has been extensively studied in Nylon 66. It is found that the Brill transition temperature is about 120 ℃ and we have also showed that the Brill transition of Nylon1012 is reversible when cooling the high temperature pseudohexagonal structure to room temperature.

Key words: Brill transition, Nylon1012, Crystal forms, Variable-temperature X-ray diffraction