Interleaved MWCNT buckypaper between CFRP laminates to improve through-thickness electrical conductivity and reducing lightning strike damage

With the recent development in fabrication of various electrically conductive composites using various conductive fillers, there is a new trend among researchers to realize electrically conductive carbon fiber reinforced composite (CFRP) for lightning strike protection. Traditional epoxy-based CFRP does not provide enough electrically conductive paths to the incident lightning current for the fast dissipation, leading to evaporation of resin and fiber damage around lightning attachment zone. In this work, multiwall carbon nanotube (MWCNT) buckypaper (BP) are interleaved between CFRP laminates to replace the resin rich area with epoxy impregnated BP. This interleaved BP not only effectively enhanced the in-plane and through-thickness electrical conductivity of the CFRP laminate but also improved resistance against lightning strikes. Electrical conductivity is improved by 697% and 643% in in-plane and through-thickness direction respectively. SEM confirmed the proper impregnation of BP and good interphase between carbon fiber and BP layers. Simulated lightning test of 40 kA is conducted on pristine and BP-interleaved composites. Improved electrical conductivity in BP composite proved to be highly effective against lightning strike confirmed by the residual mechanical test.