Deterioration Valuation of Polymer Materials in UV-ozone Generator using Microwave Plasma

Abstract

Various materials are used to sterilize medical instruments. Rubber and other products deteriorate owing to ozone and UV exposure. Ozone is capable of inactivating bacteria and fungi and is known to be effective in inactivating a wide range of viruses. Silent discharge is the mainstream method of ozone generation. The silent discharge method is also concerned with the generation of nitrogen oxides (NOX) caused by nitrogen molecules in the air, and the deterioration of electrodes during use poses a problem. Furthermore, nitrogen oxides react with water in the gaseous phase to produce nitric acid. Nitric acid reacts with several metals to form nitrates. A sterilization device using high concentrations of ozone has not been put to practical use because of the lack of an efficient method for decomposing ozone and the corrosion of metals. If a medical device is altered, it cannot be used as a sterilizing device. In this study, we exposed polymeric materials, which are often used in medical instruments, to ozone and UV light to determine whether their properties changed. Elution tests were conducted on polymeric medical materials from the viewpoints of their physical and chemical properties, functional decline, and biological safety. This study investigates changes in mechanical strength and surface chemical properties, representing the physical and chemical aspects.