Ultrasound Assisted Hybrid Carbon Epoxy Composites Containing Carbon Nanotubes

A simple approach has been reported toward the development of hybrid nano/microfiber composite structures with improved mechanical properties. Ultrasound assisted atomization process has been utilized for depositing carbon nanotubes (CNTs) on the surface of carbon fiber (CF) cloth using dilute solutions of CNTs in N, N-dimethylformamide (DMF). Dilute solutions with three different CNT concentrations such as 1 × 10⁻⁴ g/ml, 5 × 10⁻⁴ g/ml, and 10 × 10⁻⁴ g/ml were fed into an ultrasonic atomizer probe using a positive displacement syringe pump and sprayed directly on CF cloth rested on a hot plate inside a deposition chamber. Several layers of hybrid CF cloths containing CNTs were used to fabricate composite laminates using a vacuum assisted resin transfer molding (VARTM). Although the dispersion of CNTs in DMF was found very well for all three concentrations, the distribution of CNTs on CFs was only found homogeneous for 1 × 10⁻⁴ g/ml solution. It was found that the hybrid composite containing 0.3 wt. % CNTs loading fabricated using 1 × 10⁻⁴ g/ml solution showed about 25% improvement in flexural strength, although moderate improvement in flexure modulus was achieved for all three concentrations. The improved strength is believed to be due to homogeneous distribution of CNTs, which resulted in increased surface roughness and mechanical interlocking between fibers and matrix.