title: Effect of ultraviolet radiation (300-400 nanometers) on polypropylene.
abstract: Polypropylene discs and shavings were exposed to simulated ambient ultraviolet (UV) radiation (lambda 300-400 nm) for a period equivalent to at least two years of wear within the eye, assuming the eye to be exposed to ambient UV radiation for four hours per day at 1 mW/cm2. The polypropylene and the incubation media were measured by several forms of optical spectroscopy, and there was no photochemical change in either. Where polypropylene discs were exposed to a very high level of UV radiation (greater than 500 W/cm2), they became brittle and discolored within five to ten days. This level of exposure, however, was equivalent to a total of over 20 million joules/cm2, which is at least one million times levels for expected ambient UV exposure to polypropylene within the eye.
mesh_terms: D004307:Dose-Response Relationship, Radiation; D006801:Humans; D007910:Lenses, Intraocular; D010969:Plastics / Q000528:radiation effects*; D011126:Polypropylenes / Q000528:radiation effects*; D013997:Time Factors; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D010969:Plastics; D011126:Polypropylenes