Environmental factors affecting mechanical properties of facial prosthetic elastomers.

This study evaluated the degradation of elastomers for facial prostheses exposed to environmental factors normally present in a service environment. Two silicone elastomers and a polyurethane were evaluated. Samples were exposed to ultraviolet radiation, simulated sebum, ozone, chlorine, and nitrogen dioxide, and tested for tear propagation and resistance. Test results revealed significant differences in the tear characteristics between silicones and polyurethane. Differences in tear patterns were observed between the control and the specimens exposed to environmental factors. The environmental factors affected the polyurethane Epithane-3 the most and silicone MDX 4-4210 the least. When exposed to chlorine and nitrogen dioxide, Cosmesil and Epithane-3 were degraded to a point where sample testing was not possible. When exposed to ultraviolet radiation, Epithane-3 was degraded and could not be tested. Simulated sebum and ozone affected Cosmesil and Epithane-3, but no clear trends were observed.