Effect of Gamma Radiation on the Permeability of Opthalmic Preservatives Through Fluorine Surface-Treated Low-Density Polyethylene Bottles

Efforts to improve the barrier properties of polyethylene have led to the development of fluorine surface treatments in which the surface of polyethylene is changed from nonpolar to polar by replacing some of the hydrogen atoms in the polyethylene chains with fluorine atoms. The purpose of this study was to determine the effect of gamma radiation on the permeability of benzyl alcohol, phenylethyl alcohol, and 3-phenyl-1-propanol through fluorine treated and untreated 15-cm³ Boston round bottles, which were injection blow molded from low-density polyethylene (LDPE). Using a weight loss technique, it was concluded that the fluorine treatment alone improved the barrier properties, especially at elevated temperatures. Irradiation of the bottles at the 5.0- and 7.5-Mrad level also improved their barrier properties; irradiation at the 2.5-Mrad level improved their barrier properties except for untreated bottles that were stored at 50°C. Results are analyzed based on the molecular structure of the LDPE with and without fluorine surface treatment.