Infrared Laser Ablation of Gamma-Irradiated Polyamide-6

Abstract

Irradiation of polyamide-6 (PA) with γ-rays reduces its resistance to subsequent IR laser radiation. The average rate of laser ablation of PA, preliminarily irradiated with γ-rays at a dose above ~300 kGy, is almost dose-invariant and is 30% higher than that of the initial unirradiated polymer. The pattern of the dose dependence of the laser ablation rate for the samples pre-irradiated with a dose of 3.24 MGy at a dose rate of 4.2 Gy/s is mixed in character, varying from the shape characteristic of the initial polymer at the initial stage to the shape typical of the maximum radiation dose in the stationary laser ablation mode. One of the products of PA laser ablation is a dispersed polymer, consisting of nano- to micrometer-sized particles, the size range of these particles shifting toward smaller values with an increase in the γ radiation dose, a trend that is explained by a decrease in melt viscosity.