Dynamic mechanical properties of medical grade silicone elastomer stored in simulated body fluids

Abstract

Medical grade silicone rubber samples were immersed in distilled water and in pseudo-extracellular fluid (PECF) at 37.5°C for up to four months. Periodically, the storage modulus and log decrement of the samples were measured on a torsion pendulum. Up to 20% increases in storage modulus and about 40% decreases in log decrement were found over the four months independent of sample surface area. Similar trends were seen in both distilled water and in PECF. Higher (59°C) storage temperatures accelerated the changes. Small amounts of moisture uptake were detected. However, the presence of water in the samples did not cause the change in mechanical properties.