Interlaminar fracture toughness and conductivity of carbon fiber/epoxy resin composite laminate modified by carbon black-loaded polypropylene non-woven fabric interleaves

Polypropylene nonwoven fabric (PPNWF) loaded with conducive carbon black (CB@PPNWF) was prepared by manually brushing method, and then was used as interleaf material to improve the Mode I interlaminar fracture toughness (G(IC)) and interlaminar conductivity of carbon fiber/epoxy resin (CF/EP) composite laminate. The effects of post-treatment temperature and pressure on the properties of the composites, and the microstructure and relevant enhancement mechanism of the composite were investigated systematically. The results show that although PPNWF is a typical non-polar polymer with weak interfacial interaction with EP, CB@PPNWF has significantly improved the G(IC) of CF/EP composite laminate without reducing the interlaminar conductivity by means of the synergistic effects of CB particles and PPNWF. At post-treatment temperature of 80 degrees C and pressure of 3 MPa, compared to that of the control sample, the initial G(IC) (0.66 kJ/m(2)) and the propagation G(IC) (1.18 kJ/m(2)) of CB@PPNWF/CF/EP composite laminate were increased by 91.3% and 136%, respectively. The toughening mechanism mainly includes the deflection of matrix crack, the interface debonding of CB particles, the interfacial interaction enhancement of PP/EP by CB particles, and the bridging, pulling out and breakage of PP fibers.