Simultaneous enhancement of strength and toughness of epoxy using POSS-Rubber core-shell nanoparticles

The contradiction in the simultaneous improvement of nanocomposite strength and toughness has been the challenge for material researchers for more than a few decades. This work presents an epoxy nanocomposite which was reinforced with the newly-developed filler. The filler was molecularly designed to possess (a) the rigid part as inner core and (b) the soft-ductile segment which firmly bonds to the inner core as a middle layer and terminated with (c) the active functional groups, strongly bonding to matrix system. The developed filler showed the synergetic effect of each segment to enhance both strength and toughness of the nanocomposite; namely, with only 1 wt% of the newly-developed filler in the epoxy matrix, the impact resistance and the KIc respectively increases ∼80%, and ∼20%, as compared to the neat epoxy resin. The elongation at break and the tensile strength increased more than 100% and ∼50%, respectively. When filler content increased to 1.5 wt%, the tensile strength and KIc value increased, but the elongation at break and impact resistance started to decline. Therefore, 1 wt% filler content could be considered as the optimum in this resin system. The mechanism of mechanical enhancement was studied. Craze formation was observed in the epoxy nanocomposite with the developed filler. The phenomenon indicates that the newly-invented filler can solve the challenge mentioned above and it can be an excellent alternative in the future advanced material industry.