Innovative wicking and interfacial evaluation of carbon fiber (CF)/Epoxy composites by CF tow capillary glass tube method (TCGTM) with Tripe-CF fragmentation test

For improvement of mechanical property and manufacturing efficiency of fiber reinforced composites, wettability, which was affected by temperature, viscosity, the pressure of resin injection, fiber volume fraction, fiber array, and so on, was important factor, which had been focused many researchers. Although the wettability during manufacturing processing was usually evaluated by the permeability, it does not contain the surface energies for the fiber and matrix. Using innovative CF tow capillary glass tube method (TCGTM), this study investigated the wetting, wicking and interfacial properties for three type CFs reinforced epoxy composites combined with a triple-fiber fragmentation test. The CFs TCGTM was performed to evaluate wettability and wicking of CF tow with epoxy resin by measuring height of impregnated epoxy front in capillary tube more practically. After curing the specimens, contact angle between CF and epoxy was measured using FE-SEM photos directly. Wetting and wicking were also evaluated by measuring the impregnated length of epoxy droplets on CF tow, and compared with result by CF TCGTM. From all of the relating tests, the 50C type CF exhibited better wetting and wicking than 60E type CF and the desized CF. Interfacial shear strength (IFSS) were evaluated using a triple-fiber fragmentation test for three different type CFs. Better IFSS of the 50C type CF was consistent with wetting and wicking results by CFs TCGTM. A new innovative CF TCGTM can be applicable for conventional CF reinforced epoxy composites more practically by combining with micromechanical test for the IFSS between single CF and epoxy mainly.

Automated summary

This study investigated the wetting, wicking, and interfacial properties of fiber reinforced composites using an innovative CF tow capillary glass tube method. The results showed that the 50C type CF exhibited better wetting and wicking compared to the other two types, and this was consistent with the interfacial shear strength results. The new CF TCGTM can be applied practically to conventional CF reinforced epoxy composites.