Improvement in mechanical properties of carbon fabric–epoxy composite using carbon nanofibers

In the present investigation, a high-intensity ultrasonic liquid processor was used to obtain a homogeneous mixture of SC-15 epoxy resin and carbon nanofibers (CNF). The CNF were infused into the part A of the epoxy resin through sonic cavitation and then mixed with part B using a high-speed mechanical agitator. The trapped air and reaction volatiles were removed from the mixture using high vacuum. Tensile, fatigue and fracture tests were performed on unfilled, 1 wt.%, 2 wt.% and 3 wt.% CNF filled SC-15 epoxy to identify the effect of adding CNF on the mechanical properties of epoxy. The highest improvement in strength was obtained with 2 wt.% loading of CNF. The nanophased epoxy filled with 2 wt.% CNF was then used with satin weave carbon fabric in a vacuum assisted resin transfer molding (VARTM) set up to fabricate composite panels. Flexural, tensile and fatigue tests were performed to evaluate the effectiveness of CNF addition on the mechanical properties of the composite. The tensile and flexural strengths improved by 11 and 22.3%, respectively, compared to the composite without CNF. The fatigue strength was also improved significantly.