Carbon-Fiber-Reinforced Epoxy Resin with Sustainable Additives from Silk and Rice Husks for Improved Mode-I and Mode-II Interlaminar Fracture Toughness

This paper presents an effective method for enhancing both the mode I (G(IC)) and mode II (G(IIC)) interlaminar fracture toughness of carbon fiber reinforced epoxy resin (CFRE). For precursor materials, silk fibroin nanofibers (nSF) and rice husk silica were prepared from sustainable resources. Nanocomposite samples were prepared using various loading ratios of the silica and nSF in epoxy resin (EP). Mechanical stirring and sonication techniques were used to prepare homogenous mixtures of silica and nSF in epoxy resin. Non-isothermal differential scanning calorimetry and the Kissinger equation were used to examine and calculate the cure kinetics and activation energy (E-a) of EP and the composite samples. The CFRE sample with hybrid fillers of nSF and silica at the ratio 0.2/20 (wt%/wt%) exhibited the highest G(IC), and improved upon the mode-I and mode-II toughness of the pure-resin sample by 36.08% and 30.06%, respectively. Study of the fracture surfaces indicated that adding nSF and silica as fillers increases the energy required to fracture the CFRE.