A novel Fe2O3@APFS/epoxy composite with enhanced mechanical and thermal properties

Core-shell structured particle contains Fe2O3 as core and amino phenol formaldehyde resin as shell (Fe2O3@APFS) has been synthesized. The results of SEM and TEM test indicate that the obtained Fe2O3@APFS particle is monodisperse and possesses uniform core-shell structure. Its diameter is about 100 nm and the thickness of APFS layer is about 30 nm. The effects of Fe2O3@APFS on the physicochemical properties of cured epoxy composites have been systematically investigated. The cured Fe2O3@APFS/epoxy composites demonstrated enhanced mechanical and thermal properties. A maximum tensile strength of 94.3 MPa was obtained when 4 wt% loading Fe2O3@APFS particles was added. The fracture toughness of epoxy composites with 5 wt% Fe2O3@APFS loading reaches a value of up to 1.71 MPa·m1/2, which is 80% higher than that of pure epoxy resin. The glass transition temperature (Tg) of cured Fe2O3@APFS/epoxy composites was increased by 13.9 °C than that of pure epoxy resin. TEM observation illustrates that Fe2O3@APFS was monodisperse in epoxy matrix. Monodispersion of Fe2O3@APFS, covalent bond linked interface between Fe2O3@APFS and epoxy matrix and synergistic effect of Fe2O3 and APFS were responsible for the enhanced mechanical and thermal properties of epoxy composites. This work provides a new insight into the combination of soft and rigid fillers used to modify polymer.