Multifunctional hybrid composites from novel asphaltene-based carbon nanofiber mats and woven carbon fiber

This study reports, for the first time, the use of lower-cost, more sustainable, electrospun carbon nanofiber from asphaltene-based precursors as interleaves in multifunctional composites with improved mechanical and electrical performance. First, asphaltene-based nanomats were electrospun with and without prior asphaltene feedstock purification, including multistage purification. The carbon nanofiber mats, extracted after purification, spinning, thermal stabilization, and carbonization, exhibited improved quality and morphology with reduced beading after purification. Hybrid composites were fabricated using vacuum-assisted resin infusion, incorporating commercially available plain weave carbon fabric layers and the developed nanofiber mats as interleaves in an epoxy matrix. The nanofiber mat reinforcement increased the interlaminar shear strength of the composites by 18% without compromising flexural properties. In general, it was found that purification of asphaltene did not affect the interleave effects, whereas all nanomats resulted in similar enhancement of interlaminar strength and modulus at the interlaminar region. However, using purified nanofiber mats significantly improved the electrical conductivity of the hybrid composites, which can be attributed to an increase in their specific surface area after purification. Hybrid composites produced using purified nanofiber mats showed the highest electrical conductivity, improving both in-plane and out-of-plane conductivities by 173% and 198%, respectively, compared to control carbon fiber-epoxy composites.