Volume resistivity of ultra-thin chopped carbon fiber tape reinforced thermoplastics

This study concerns the development of a reliable method to measure the volume resistivity of ultra-thin chopped carbon fiber tape reinforced thermoplastics (UT-CTT) made by tow spreading technology. It was found that, by using vises with aluminum foil and silver paste, resistivity can be accurately evaluated and the in-plane volume resistivity of UT-CTT decreased with increasing tape length and decreasing tape thickness. However, an increase in tape thickness led to a decrease in out-of-plane resistivity. The resistivity also had smaller coefficient of variation (CoV) in UT-CTT specimens that included a greater number of chopped tapes for a given volume. This makes it possible to achieve a volume resistivity in UT-CTT that is close to that of quasi-isotropic laminates, despite the discontinuity of the carbon fiber, with potential applications improving lightning resistance and electromagnetic interference (EMI) shielding.