Electron beam irradiation influencing the mechanical properties and water absorption of polycaprolactam (PA6) and polyhexamethylene adipamide (PA66)

It is known that polycaprolactam (PA6) and polyhexamethylene adipamide (PA66) are widely used industrial materials including in the irradiation industry. However, there is a lack of observation of irradiation effects on PA6 and PA66. In the current study, we firstly investigated mechanical and water absorption properties of PA6 and PA6 that were treated under irradiation doses of 200 kGy, 400 kGy, 800 kGy and 1600 kGy, respectively. The structure, mechanical properties and thermal properties of nylon after irradiation were characterized by mechanical property tests, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results indicated that the tensile strength of PA6 increased gradually while that of PA66 firstly increased and then decreased with the increase of irradiation dose. Additionally, the elongation at break of the two samples decreased obviously with the increase of irradiation dose. The water absorption of PA6 increased with the increase of irradiation dose; however, that of PA66 was almost constant regardless of irradiation. FTIR tests revealed that the carbonyl index of PA6 and PA66 increased with the increase of irradiation dose. SEM results illustrated that surface degradation of PA6 and PA66 occurred during the irradiation process.