Durability Assessment of Styrene- and Epoxy-based Shape-memory Polymer Resins

The present study is a baseline assessment of the durability of styrene- and epoxy-based shape memory polymer resin materials being considered for morphing applications when exposed to service environment. The approach for the experimental evaluation is a measurement of the shape memory properties and elastomeric response before and after separate environmental exposure to (i) water at 49 degrees C for 4 days, (ii) in lube oil at room temperature and at 49 degrees C for 24 h, and (iii) after exposure to xenon arc (63 degrees C, 18 min water and light/102 min light only) and spectral intensity of 0.3-0.4 watts/m(2) for 125 cycles (250 h exposure time). Parameters being investigated include modulus in the rubbery and glassy state, stored strain, shape fixity, stress recovery ratio, and linear shape recovery. In addition, we monitor changes in specimen color, weight, and dimensions along with onset of damage due to conditioning and subsequent thermomechanical cycling.