Crystallization behaviors of secondarily quenched Nylon 6

• Published in: Materials letters 2007-02, Vol.61 (3), p.925-928
• Main Authors: Zhao, Zhudi, Zheng, Weitao, Tian, Hongwei, Yu, Wenxue, Han, Dong, Li, Bo
• Format: Article
• Language: English
• Subjects: Isothermal crystallization; Nylon 6; Secondary quenching; X-ray
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2006.06.014

We observed a very unusual crystallization behavior in Nylon 6 by X-ray diffraction. The melted Nylon 6 films were quenched in oil baths with different temperatures for isothermal crystallization. When the Nylon 6 films were isothermally crystallized above 180 °C for 30 min and then quenched in ice water, three sharp diffraction peaks at 2 θ = 9.4, 18.95 and 28.5° were observed in X-ray diffraction patterns. No diffraction peaks could be found at 2 θ = 9.4, 18.95 and 28.5° from a series of calculated 2 θ values for the α, γ, β and pleated α form crystals of Nylon 6. The locations of these peaks do not correspond with calculated 2 θ values. When the film was slowly cooled from the melt state to 180 °C and was maintained at 180 °C for 30 min and then quenched to 0 °C, it could be found that these three reflections disappeared. If the Nylon 6 film isothermally crystallized at 180 °C for 30 min was not quenched to room temperature, but cooled to room temperature in air, these three diffraction peaks could not be observed.