In-Situ Growing Polymer Particles on Carbon Fiber for Improving Interfacial Properties of Epoxy Composites

To greatly improve the interfacial adhesion between carbon fiber and epoxy matrix, herein, we report a rapid and efficient method of growing polymer microspheres on carbon fiber (CF) by in-situ thiol-isocyanate click dispersion polymerization with the presence of polyvinylpyrrolidone (PVP). The surface morphology observations of modified CF by scanning electron microscopy (SEM) indicated an obvious increase in surface roughness. Fourier-transform infrared (FT-IR) spectra, X-ray photoelectron spectra (XPS) and thermogravimetric analyses (TGA) confirmed the introduction of functional groups on CF. Dynamic contact angle and surface tension measurements displayed the enhancements of wettability and surface energy of CF. Compared to the untreated carbon fiber, the transverse fiber bundle tensile strength (TFBT) and interfacial shear strength (IFSS) of modified carbon fiber/epoxy composites increased 150.97% and 68.47%. Simultaneously, the single fiber tensile strength of modified CF also showed an increase by 9.65%. Finally, schematic model of interphase reinforcing mechanism was analyzed.