Polyamide-6: The effects on mechanical and physicochemical properties by electron beam irradiation at different temperatures

• Electron beam irradiation in polyamide-6 produced higher crosslinking than in polyamide-6,6.
• Crosslinking took place mainly in the amorphous phase of the polymer.
• Polyamide-6 melting point slightly decreased with the increase in irradiation dose and crystallinity remained practically unchanged.
• Mechanical properties were strongly affected by irradiation dose.
• Irradiation above Tg significantly increased the changes in thermal and mechanical properties respect to irradiation at ambient temperature.

The electron beam irradiation of polyamide-6 (PA-6) films was carried out in air over a range of 50–1000 kGy at varying temperatures and a dose rate of 5.1 kGy min−1. The effects of the irradiation at temperatures above and below the glass transition temperature (Tg) on the thermal and mechanical properties were studied. Melting and crystallization temperatures decreased significantly with the increase in irradiation dose, whereas percent of crystallinity varied only slightly and Tg slightly increased for irradiated samples respect to non irradiated one with no significant effect of the dose. Mechanical properties were affected by irradiation. The material became more rigid with a direct relationship between the mechanical properties and the irradiation dose. The irradiation above Tg led to a larger variation in the thermal and mechanical properties respect to the irradiation below Tg. The changes in properties were related to the crosslinking produced in the amorphous part of the polymer by the electron beam irradiation.