Experimental Multi-scale analysis of Carbon/Epoxy Composites Nano-Reinforced by Carbon Nanotubes/Multi-layer Graphene
Nano-size structures, nanotubes/multi-layer graphene (CNT/MLG), were dispersed into epoxy system by a combination of sonication and high shear mixing. To avoid CNT/MLG agglomeration, a non-covalent functionalization were performed using surfactants, CO890 - Polyoxyethylene (40) nonylphenyl ether and SDBS - sodium dodecyl benzene sulfonate. Raman spectroscopy and Fourier transformed Infra-red analysis indicated that CO890-MLG and SDBS-CNT have strong chemical interactions. Atomic force microscopy revealed formation of "spike-like" nanostructures for SDBS-CNT combination and "wall-like" nano-shape structures for the CO890-MLG ones. Tensile tests data indicate no significant change on stiffness. In average, the ultimate stress increased around 18%, while toughness had an improvement close to 62%. SDBS-CNT and CO890-MLG at small concentrations (0.075 wt. %) are probably the best options for nano-reinforcement of carbon/epoxy composites.