Synergistic Effects of Acrylic/Silica Armored Structured Nanoparticles on the Toughness and Physicomechanical Properties of Epoxy Polymers

To take full advantage of the synergistic effects of soft organic and rigid inorganic toughening agents, elastomeric core/amine-functionalized silica shell armored nanocomposite particles were prepared through Pickering emulsion polymerization. The size and microstructure of the prepared armored impact modifier particles (AIMPs) were studied thoroughly. It was substantiated that the amine-functional silica nanoparticles have been successfully attached to the surface of the colloidal polymer particles. The obtained results revealed that the incorporation of the prepared AIMPs into epoxy resin could exert significant positive influences on its toughness, tensile strength, and modulus. An optimal content of AIMPs was found to exist, which enhanced the fracture toughness by 8 times, the fracture energy by 50 times, and the tensile strength by 38% for the modified sample using 7 wt % AIMPs in comparison with those of the neat epoxy resin. The primary toughening mechanisms were related to crack pinning and deflection as well as deboning of AIMPs from the epoxy matrix followed by plastic void growth.