R-Curve Behavior of Polyhedral Oligomeric Silsesquioxane (POSS)–Epoxy Nanocomposites

Polyhedral oligomeric silsesquioxane (POSS) is a suitable nanoscale reinforcement for thermosetting polymers, such as epoxy resin systems in order to modify its mechanical, thermal and chemical properties. The inclusion of POSS the at higher loading (greater than 1 wt.%); however, it introduces ductility during fracture behavior these nanocomposites. Consequently, J-integral used quantify materials characterize crack growth resistance curve against stable growth. A range nanocomposites prepared by adding 0.5, 1, 3, 5, 8 wt.% glycidyl into DGEBF cured with an amine-based curing agent. From toughness experiments, load-displacement result confirms that when greater wt.%, nanocomposite changes from brittle ductile. For both ductile nanocomposites, addition molecules improves initiation toughness. development POSS–POSS compliant domains, reported previously, responsible this change failure behavior. fractured images POSS–epoxy obtained using scanning electron microscopy, show increase values occurs due extensive shear yielding. Meanwhile, increased lower pinning deflection.