Effects of nano-SiO_2 modified emulsion sizing on the interfacial performance of carbon fiber reinforced plastics

A single fiber fragmentation test, three-point bend test, scanning electron microscopy and dynamic mechanical thermal analysis (DMTA) were performed to study the influence of nano-SiO_2 modified emulsion sizing on the interfacial properties of carbon fibers reinforced plastics (CFRP). As a comparison, CFRP with and without sizing but not modified by nano-SiO_2 were also investigated. Results showed that the interfacial shear strength (IFSS) values of the CF with modified sizing and unmodified sizing were increased by 79% and 41%, respectively, compared to the CF without sizing. The interlaminar shear strength (ILSS) values of the CFRP with modified sizing and unmodified sizing were also increased by 14% and 9%, respectively compared to the CFRP without sizing. Furthermore, the loss tangent (tanδ) of CFRP with modified sizing declined to 18% and glass transition temperature (T_g) was increased by 5℃, compared to the CFRP with unmodified sizing in the DMTA chart. So the interfacial adhesion performance of the CFRP with modified sizing by nano-SiO_2 was evidently increased.