Durability of shape memory polymer based syntactic foam under accelerated hydrolytic ageing

In this study, accelerated hydrolytic ageing of shape memory polymer (SMP) based syntactic foam after two-dimensional (2D) programming or training (compression in one direction and tension in the transverse direction) was investigated experimentally. Mechanical properties and shape recovery functionality of the aged foam were tested. The results indicate that the moisture absorption for original and programmed foams is less than 1% at room temperature for 90 days. The moisture absorption in saltwater is less than that in rainwater, and the original foam absorbs more moisture compared to the programmed foam. Hydrolytic aged foams exhibit a slight decrease in mechanical strength, and show an increase in ductility, regardless of the original or programmed foams. Water immersion also leads to lowering in glass transition temperature of the foam. Furthermore, the rainwater has a larger influence on the mechanical properties than the saltwater does. It is concluded that the foam basically maintains its shape recovery functionality after 2D programming and moisture attacks.