Effect of fiber shapes on physical characteristics of non-circular carbon fibers-reinforced composites

Round, hollow, and C-shape carbon fibers (CF)-reinforced composites were investigated to study the effect of carbon fiber shapes on physical properties. The damping factor was measured by FFT-analyzer and the mechanical properties were evaluated using the Instron. Also, surface free energy analysis was executed to examine the relationship between the shape of fiber and wettability on composites. As a result, it was found that C-CF/epoxy (EP) composites showed the highest values in mechanical properties, while R-CF/EP composites the lowest values. This was due to the wider interfacial contact area between reinforcement and matrix that could effectively transfer the applied load. C-CF/EP composites had a greater damping factor than round and hollow-shape ones. This meant that C-shape carbon fiber played a more important role in damping of fiber-reinforced composites, owing to have wider contact area. Also, C-shape carbon fiber had the highest surface free energy than that of other carbon fibers. This wettability made it increase in mechanical properties in composites, due to the stronger interfacial binding force.