Effect of carbon nanotube addition in two sizing agents on interfacial properties of carbon fiber / polycarbonate composites

Abstract

In order to improve the interfacial bonding between carbon fiber (CF) and polycarbonate (PC), sizing agents of water-borne polycarbonate (WPC) and water-borne polyurethane (WPU) containing carbon nanotubes (CNTs) were used to treat CFs. CNTs were dispersed in the two sizing agents after treated with concentrated nitric acid. The effects of the type of sizing agents and the CNT content on the interfacial properties of composites were investigated by two methods, single fiber fragmentation test (SFFT) for monofilament reinforced composite and transvers tensile for directional bundle composite. Results show that WPU is more conducive to improving the interfacial bonding properties of CF/PC composites because of its better film-forming property than WPC, and the addition of CNTs has a beneficial effect on the interfacial properties of composites when the content of CNTs is 0.1 wt%. Over dose of CNTs causes agglomeration, which is unfavorable for the improvement in interfacial properties. CNTs can effectively prevent interfacial slip, thus significantly improve the interfacial properties in SFFT, while the improvement is not obvious in transvers tensile because the adhesion of the sizing agents plays a leading role.