Graphitic carbon nanofiber (GCNF)/polymer materials. I. GCNF/epoxy monoliths using hexanediamine linker molecules.

Processing methods have been optimized for the formation of graphitic carbon nanofiber (GCNF)/epoxy nanocomposites containing GCNFs highly dispersed throughout a thermoset epoxy matrix. GCNFs having a herringbone atomic structure are surface-derivatized with bifunctional hexanediamine linker molecules (GCNF-HDA) capable of covalent binding to an epoxy matrix during thermal curing and are cut to smaller dimension using high-power ultrasonication. GCNF-HDA nanofibers are dispersed in epoxy resin at 0.3 wt.% loading using variable levels of ultrasonication processing prior to thermal curing. Effects of sonication power on the quality of the GCNF-HDA/epoxy material obtained after curing have been determined from flexural property measurements, thermomechanical analysis and SEM/TEM imaging. GCNF-HDA/epoxy material of the highest quality is obtained using low-power sonication, although high-power sonication for short periods gives improved flexural properties without lowering the glass transition temperature. Good dispersion and polymer wetting of the GCNF component is evident on the nanoscale.