Enhancing interfacial strength of epoxy resin composites via evolving hyperbranched amino-terminated POSS on carbon fiber surface

A self-synthesized octa(gamma-chloropropyl) polyhedral oligomeric silsesquioxanes (POSS) and its evolutionary amino-terminated hyperbranched structure were introduced onto the carbon fibers (CFs) surface (CF-G(n)-POSS-NH2, n = 1, 2 and 3) by chemically and successively grafting method to improve the interfacial properties of CFs/epoxy composite. The fiber surface structures could be tuned through regulating grafting generation (n) of CF-G-POSS-NH2, and the polarity and roughness of CF surface increased with the incremental dendritic generation number. Interfacial shear strength (IFSS), interlaminar shear strength (ILSS) and dynamic mechanical properties of the functionalized CFs composites improved as the grafting generation increased, which may be attributed to the varying degrees of chemical interaction, mechanical interlocking and resin wettability provided by hyperbranched G(n)-POSS-NH2 interface. Moreover, the interfacial structure has been also speculated and analyzed.