A novel route for tethering graphene with iron oxide and its magnetic field alignment in polymer nanocomposites. (5th August 2016)

• Record Type: Journal Article
• Authors: Wu, Shuying; Zhang, Jin; Ladani, Raj B.; Ghorbani, Kamran; Mouritz, Adrian P.; Kinloch, Anthony J.; Wang, Chun H.
• Is Part Of: Polymer. Volume 97(2016)
• Page Start: 273
• Page End: 284
• Publication Date: 2016-08-05
• Subjects: Fe3O4/PVP-GNPs -- Magnetic field alignment -- Epoxy nanocomposites -- Fracture toughness -- Electrical conductivity; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2016.05.024
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: We present a new route of tethering graphene nanoplatelets (GNPs) with Fe3 O4 nanoparticles to enable their alignment in an epoxy using a weak magnetic field. The GNPs are first stabilized in water using polyvinylpyrrolidone (PVP) and Fe3 O4 nanoparticles are then attached via co-precipitation. The resultant Fe3 O4 /PVP-GNPs nanohybrids are superparamagnetic and can be aligned in an epoxy resin, before gelation, by applying a weak magnetic field as low as 0.009 T. A theoretical model describing the alignment process is presented and used to quantify the effects of key parameters on the time needed for the alignment process. Compared to the unmodified epoxy, the resulting epoxy polymer nanocomposites containing randomly-oriented Fe3 O4 /PVP-GNPs nanohybrids exhibit significantly improved electrical conductivities by up to three orders of magnitude and fracture energies by up to 300%. The alignment of the Fe3 O4 /PVP-GNPs nanohybrids in the epoxy polymer nanocomposites transverse to the direction of crack propagation further increased the fracture energy by 50%, and the electrical conductivity by seven fold in the alignment direction, compared to the nanocomposites containing randomly-oriented nanohybrids. Graphical abstract: Highlights: Graphene hybrids (Fe3 O4 /PVP-GNPs) were fabricated by non-covalently attaching Fe3 O4 to PVP-stabilized GNPs. Alignment of Fe3 O4 /PVP-GNPs in epoxy was studied experimentally and theoretically. Fe3 O4 /PVP-GNPs can be aligned in epoxy by a weak magnetic field as low as 0.009 T. Electrical conductivity was higher in the alignment direction. Significantly higher fracture toughness was achieved by aligning Fe3 O4 /PVP-GNPs.