Incorporation of Carbon Nanotubes on Strategically De-Sized Carbon Fibers for Enhanced Interlaminar Shear Strength of Epoxy Matrix Composites

Carbon fiber reinforced polymeric matrix composites are enormously used in aerospace and automotive industries due to their enhanced specific properties. However, the area of interlaminar shear properties still needs investigation so as to produce composites with improved through-the-thickness properties. To improve interlaminar shear properties of these composites, acid-functionalized multiwalled carbon nanotubes were deposited on de-sized carbon fibers through electrophoretic deposition. De-sizing of carbon fabric was performed through three different methods: furnace heating, acidic treatment and chloroform usage. As the acid-treatment provided better results than other two techniques, the acid-de-sized carbon fibers were coated with nanotubes and subsequently incorporated in epoxy matrix to prepare a novel class of multiscale composites using vacuum assisted resin transfer molding technique. Nearly 30% rise in the interlaminar shear strength of the composites was obtained which was credited to the coating of nanotubes on the surface of carbon fibers. The increased adhesion between carbon fibers and epoxy matrix due to mechanical interlocking of nanotubes was found to be the possible reason of improved interlaminar shear properties.