Magnetic alignment of SWCNTs decorated with Fe3O4 to enhance mechanical properties of SC-15 epoxy

We report significant improvement in mechanical properties of SC-15 epoxy when reinforced with decorated nanotubes and cured in a modest magnetic field. The chemical synthesis and field curing process is a low cost and relatively easy technique to impose strong magnetic anisotropy into the system without the need of a superconducting magnet. SWCNT(COOH)s were decorated with Fe3O4 nanoparticles through a sonochemical oxidation process and then dispersed into SC-15 epoxy at 0.5 wt% loading. The admixture was cured for 6 hours in a magnetic field of 10 kOe followed by an additional 24 hours of post curing at room temperature. Control samples were prepared in a similar manner but without the application of the magnetic field. Mechanical tests performed on field-cured samples indicated that tensile strength and modulus increased by 62% and 40%. Most importantly, modulus of toughness, fracture strain, and modulus of resilience improved by 346%, 165%% and 170%, respectively. Such enhancement in mechanical properties was attributed to changes in polymer morphology, partial alignment of nanotubes in the field direction, and sliding at the polymer-nanotube interface. Detailed characterization of the system with XRD, TEM, DMA, and Magnetometry are described in the paper. Copyright 2013 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License. [http://dx.doi.org/10.1063/1.4800698]