Laser induced graphene fibers for multifunctional aramid fiber reinforced composite

Aramid fiber reinforced composites have been limited to ballistic applications due to their poor structural performance, easy delamination, and their lack of multifunctionality. Given the poor adhesion of aramid fibers to polymeric matrices, the resulting composites suffer from weak interfacial and interlaminar properties. In this work, laser induced graphene (LIG) is formed directly on the surface of aramid fabrics with varying morphology to simultaneously improve the interlaminar strength of the composite and introduce multifunctionality. The LIG morphology is optimized for maximum improvement to the mechanical performance of the aramid fiber reinforced composite yielding a 70% and 20% increase in both short beam strength and Mode I fracture toughness, respectively. Remarkably, the improvement in interlaminar properties are reached while fully maintaining the specific strength and damping properties of the aramid fabric following the induction process. The improved interlaminar properties are attributed to the enhanced chemical interaction with the oxidized graphitic layer and mechanical interlocking across the interlaminar region due to the presence of the LIG. In addition, the LIG is shown to allow surface conductivity in aramid composites. This work shows that LIG can act as nanoscale building block in aramid fiber reinforced composites in order to provide a fast and cost-effective improvement to the mechanical performance and multifunctionality for structural applications.