Abstract
Wavelength dependence of the photodegradation of nylon 6 was investigated by using spectrally dispersed light in the wavelength range of 300 and 550nm. On irradiation with light above 300nm, the dynamic modulus E′ was increased at each wavelength between 300 and 500nm. From measurement of [η] and X-ray diffraction, it was found that the increase in E′ by irradiation was a result of crystallization accompanied by scission reaction between amide groups. Change in E′ as a function of irradiation time was linear and was expressed by the equation, E′(t)=E0′+kt, where E′(t) is the dynamic modulus at time t, E0′ is that at t=0, and k is the rate constant. In the tanδ versus temperature curve of nylon 6 irradiated at the wavelength above 300nm, the α-relaxation (85°C) was broadened and the intensity of the β-relaxation at -45°C was lowered. However, behavior of the γ-relaxation (-100°C) was not changed.
