Interfacial enhancement of nano-SiO2/polypropylene composites

The authors proposed an approach for manufacturing nano-SiO2/polypropylene (PP) composites by in situ reactive processing. The key issue lies in that the nanoparticles were covalently bonded to the matrix polymer via polyurethane (PU) elastomer and PP-g-NH2. Unlike the previous techniques based on graft polymerization, the present one did not need to pretreat the nanoparticles. Taking the advantages of rubber-type grafting polymer (i.e. PU) and interfacial reactive compatibilization with PP-g-NH2, a synergetic toughening effect was observed for the PP nanocomposites. Only very low concentrations of nano-SiO2 (1.5–2.5 vol.%) and PU (<4 vol.%) were sufficient to greatly increase notched impact strength of PP. Meanwhile, tensile properties of the nanocomposites were also slightly enhanced.