FABRICATION AND EVALUATION OF EPOXY NANOCOMPOSITES AND CARBON/EPOXY COMPOSITE LAMINATES CONTAINING OXIDIZED CARBON NANOFIBERS

摘要

Vapor grown carbon nanofibers (VGCF) were dispersed into an epoxy/amine resin at a level ofrn8 wt% using a high shear, solvent-free process. Six batches of VGCF which differed in thernamount of surface oxidation were used in this study, in addition to two control batches of nonoxidizedrnVGCF. The resulting resin mixtures were evaluated for dispersion quality, and thenrncured under heat and pressure to form solid plaques. Samples were then evaluated for glassrntransition temperature (T_g), flexure strength, and impact strength. The dispersion quality variedrnfrom batch to batch, with batches containing oxidized VGCFs generally containing fewer andrnsmaller agglomerated nanofibers than those containing non-oxidized VGCFs. The T_g values ofrnthe nanocomposites were the same or up to 7℃ higher than a neat resin sample. Flexurernmodulus and strength varied from batch to batch, but one batch showed a 237% increase inrnmodulus and 29% increase in flexure strength over neat resin. This same batch also exhibited arn24% increase in Izod impact strength compared to neat resin, although other batches performedrnmore poorly than neat resin. Additional nanofiber/resin mixtures were prepared and used torndemonstrate the production of carbon fiber composite laminates using a Resin Film Infusionrntechnique. The impact strength of the carbon fiber laminates containing VGCFs was about 73%rnhigher than those containing no VGCF. However, these results are initial, and fiber volumernfraction and void content differences may be partly responsible for variation in impact strength.