Effect of accelerated aging on the viscoelastic properties of Elast-Eon (TM): A polyurethane with soft poly(dimethylsiloxane) and poly(hexamethylene oxide) segments

The viscoelastic properties of cylinders (diameter 5 mm, height 22 +/- 0.2 mm) of Elast-Eon (TM) 3, (a polyurethane with poly(dimethylsiloxane) and poly(hexamethylamine oxide) segments) were investigated before and after the specimens had undergone accelerated aging in saline solution at 70 degrees C for 38, 76 and 114 days (to simulate aging at 37 degrees C, for 1,2 and 3 years, respectively). All sets of specimens were immersed in physiological saline solution at 37 degrees C during testing and the properties were measured using dynamic mechanical analysis (DMA). A sinusoidal cyclic compression of 40 N +/- 5 N was applied over a frequency range, f, of 0.02-100 Hz. Values of the storage. E', and loss. E '', moduli were found to depend on f; the dependence of E' or E '' on the logarithm (base 10) off was represented by a second-order polynomial. After accelerated aging, the E' and E '' increased significantly (p