Temperature Dependent Mechanical Properties and Structure of Nylon 6

The temperature dependent stress-strain curves of Nylon 6 were obtained via tensile hot stage, and the in situ WAXS experiments were measured simultaneously. The results indicated that the temperature related yield stress, breaking strength and modulus of Nylon 6 can be described by the Arrhenius equation. During the process of stretching Nylon 6 experienced elastic deformation, yield, strain hardening and fracture. The yielding on Nylon 6 stress-strain curves was unobvious with the low draw rate, meanwhile, the yielding turned to more unobvious gradually at higher stretching temperatures. The stress-strain curves of Nylon 6 are similar to each other within the measured temperature range. Nevertheless,the yield strength and modulus decreased with the increasing of stretching temperature. By analyzing the WAXS profile, it was found that the alpha-phase gamma-phase ratio of undeformed Nylon 6 samples decreased along with the temperature increased. Also, at high temperatures,the crystalline phase of Nylon 6 slipped and/or melted during tensile deformation more easily. In the meantime,the relationship between the stretching temperature and mechanical properties was obtained after fitting the temperature dependent results. It was found that the temperature related relationship obeys the Arrhenius equation. In addition, the viscosity dependence of yield stress was given in the paper.