Mechanical Properties of Tow Prepreg Applied to AFP using Surface-tackiness

This study presents the production of a carbon-fiber composite material using a thermosetting epoxy resin and Polyether Sulfone (PESU), a thermoplastic toughening agent. A tow prepreg was fabricated using the proposed high-toughness resin, and it was applied to the automated fiber placement (AFP) process. To obtain resin with different viscosities, different ratios of solid epoxy YD-011 were mixed with the high-toughness resin, which contained liquid epoxy YD-128 and 10 phr of PESU, at certain ratios. The surface-tackiness of each mix of resin was then compared by applying the tow prepreg that was produced to the AFP process. The results indicate that the resin mix that contained 10 % of solid epoxy was the most suitable for the AFP process. Subsequently, the mechanical and thermal properties of the resin and tow prepregs using only the liquid epoxy containing the PESU were compared with the resin and tow prepregs that contained 10 % solid epoxy. The resin produced by adding 10 % solid epoxy to the liquid epoxy exhibited improvements of 3 % in tensile strength, 16 % in tensile modulus, and 27 % in impact strength when compared to the resin that used only the liquid epoxy. Furthermore, the fracture toughness test results using single-edge notched bending and compact tension methods showed a decrease of 10 % and 16 %, respectively, and the glass transition temperature decreased by 5 %. In the case of the tow prepreg specimen produced by adding 10 % solid epoxy to the liquid epoxy, it exhibited a decrease of 0.6 % in the 0 ° tensile strength, a decrease of 1.6 % in tensile modulus, and an increase of 4 % in the 90 ° tensile strength when compared to the tow prepreg that applied only the liquid epoxy. In addition, the ILSS interfacial strength increased by 1 %, while the double cantilever beam fracture toughness decreased by 8 %. A comparison of the results showed that the tow prepreg prepared by adding 10 % solid epoxy to the liquid epoxy had excellent mechanical properties, and the tow prepregs were laminated most appropriately in the AFP process, thus verifying its applicability as a resin in tow prepregs for the AFP process.