Effects of e-beam irradiation on the chemical, thermal, and mechanical properties of polyamide-6, polyamide-6.6, and polypropylene used in conveyor belt rollers

Abstract

In this study, polyamide 6 (PA 6), polyamide 6.6 (PA 6.6), and polypropylene (PP) polymers were irradiated with an e-beam (EB) (100 and 200 kGy doses, 100 kGy.s-1 dose rate, at room temperature) to evaluate the effects on radiochemical crosslinking. Mechanical analyses (tensile, flexural, and tribological tests), thermal characterizations (TGA, DSC, and glow wire test), and FTIR spectroscopy were performed. Results demonstrated that PA 6.6 irradiated at 200 kGy exhibited a 6.8% increase in tensile strength at break, being the only material showing improvement in yield point. All samples displayed reduced elongation after irradiation. In flexural resistance tests, both irradiated PA 6 and PA 6.6 showed enhanced properties, while in tribological evaluations, only PA 6.6 (100 kGy) presented a reduced friction coefficient. Thermal analyses revealed that irradiated PA 6.6 showed increased onset degradation temperature, while all polymers exhibited decreased melting temperature. The crystallinity percentage increased in both irradiated PA 6.6 and PP, and only PA 6.6 (200 kGy) resisted all temperature levels in the glow wire test. It was concluded that PA 6.6 demonstrated superior post-irradiation performance, showing more enhanced properties compared to PA 6 and PP. © 2025 Universidade Federal de Sao Carlos.