Modifying the carbon fiber-epoxy matrix interphase with silicon dioxide nanoparticles

Nanoparticle modification of the carbon fiber-epoxy interface was investigated by depositing silicon dioxide (SiO 2 ) nanoparticles on the surface of carbon fibers (CFs) using a conventional sizing process by immersing CFs tows in a SiO 2 nanoparticle suspension. The surface density of the nanoparticles and the uniformity of their dispersion were characterized by scanning electron microscopy. CF-epoxy composites were fabricated to study the effect of the SiO 2 nanoparticle coating on the CF-epoxy composite interfacial properties. Interfacial adhesion was assessed by measuring the interfacial shear strength (IFSS) with the single fiber fragmentation test. A 44% improvement of the IFSS was obtained with a SiO 2 relative concentration of 1.3 wt%, compared with non-coated CFs. This increase was the result of an increase of the shear modulus of the matrix in the interphase region caused by the presence of the SiO 2 nanoparticles. Coating CFs with SiO 2 nanoparticles has been shown to be a simple, scalable, and cost effective method to increase the interfacial mechanical properties in CF-epoxy composites. The carbon fiber surface was modified by silicon dioxide nanoparticles by immersing CFs tows in a SiO 2 nanoparticle suspension. A significant increase of the IFSS was obtained.