Improvements in High Specific Strength Epoxy-Based Composites using High Magnetic Fields
H. Mahfuz, S. Zainuddin, V.K. Rangari and S. Jeelani
Tuskegee University, US
high magnetic field, magnetic flocculation, nanoparticles, epoxy
Numerous studies have been carried out, over a period of several years, on the detection of changes in physical characteristics of polymers subjected to high magnetic fields during the curing stages. Extremely large increases in the tensile elastic modulus have been reported, with values of up to 8.1GPa for samples cured in fields of 12 T, compared to 3.1GPa for samples cured in zero field. Additionally, a wide body of literature provides convincing evidence that an infusion of nanoparticles (NPs) can bring about enhancement of various mechanical properties of polymer composites. The present paper describes an attempt to combine these two separate bodies of work and to use high magnetic fields as a means of obtaining superior distributions of NPs in epoxy-based composites. Here, we describe the results of preliminary experiments designed to improve upon the bulk mechanical properties of such composites by subjecting the fluid mix, during the curing process, to high uniform magnetic fields. The aim here is to bring about magnetic flocculation of these NPs during the curing process and, in particular, during the pre-gel stage at which time the viscosity of the matrix is still relatively modest. In the experiments described here, the fluid matrix chosen was an epoxy resin system, SC-15, of the sort used extensively in aerospace and other commercial industries. Two principal types of NPs were used: SiC and TiO2, with respective diameters of 29nm and 30 nm. Compression tests conducted on these composites have shown significant improvement in strength and stiffness. The improvement in properties was in the range 40-120% with SiC particles being in the lower boundary.
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Nanotech 2005 Conference Program Abstract