Surface modification of carbon fiber by vinyl functionalized silane to enhance the interfacial adhesion with rubber via co-vulcanization

The application of carbon fiber reinforced rubber composites was restricted by the poor interfacial combination. To construct an effective interfacial transition layer, vinyl polysiloxane was introduced to be a chemical bridge connecting carbon fiber and rubber in this study. A modification method was designed since silicon hydroxyl generated from hydrolysis vinyl siloxane could be connected with carbon fiber through ether bond while unsaturated vinyl groups could be used as crosslinking point to form interpenetrating network by following vulcanization. This mechanism was confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy characterization for the surface of carbon fiber during modification. The immigration of sulfur from rubber matrix to the established interfacial layer was also verified by the distribution of sulfur element based on scanning electron microscopy-energy dispersive spectroscopy results. The contact angle and H-shape pull-out test was applied to evaluate the surficial activity of carbon fiber and the interfacial properties of carbon fiber reinforced rubber composites. The results showed that the interfacial performance was improved significantly since the H-shape pull-out force of modified carbon fiber reinforced rubber, which means the strength of the interfacial layer, could be more than 3 times as that of untreated samples.