Manufacturing and Flexure Properties Characterization of Hybrid Nano-/Micro-Fiber Reinforced Epoxy Composites

We report an approach for the deposition of carbon nanotubes (CNTs) on carbon fabrics (CFs) en route for the development of hybrid nano-/micro-fiber composite structures. Ultrasonic atomization process was utilized for the direct deposition of CNTs on the surface of carbon fiber fabric. A dilute solution of CNTs was prepared by dispersing very small amount of multi walled CNTs (MWNT) in N,N-Dimethylformamide (DMF) using a low frequency ultrasonic water bath. The dispersed solution was then fed into the ultrasonic atomizer probe using a syringe pump and sprayed directly on the carbon fiber fabric rested on a hot plate. The dispersion of MWNTs in DMF solvent was characterized using UV spectroscopy and the distribution of CNTs on CF was characterized using scanning electron microscopy (SEM). Vacuum assisted resin transfer molding (VRTM) was used to manufacture composite laminates using several layers of CNTs hybrid CF fabrics. We prepared hybrid composite laminates containing 0.03-wt% of CNTs. Dispersion of CNTs in DMF and distribution of CNTs on CFs was found to be very good which we believed to be resulted in about 15% improvement in flexure strength and about 12% improvement in strain to failure compared to neat composites. Such improvements in composite properties with only 0.03% CNTs are very promising in hybrid composite structures.