Mechanochemical Organic Functionalization of Graphite Produces Tunable Coatings of Carbon Fibers by Multilayered Graphite Microparticles

The properties of carbon fiber reinforced composites depend on the adhesion of fibers to the polymer matrix. The improvement of interfacial properties in carbon fiber containing composite materials was extensively studied by introducing water-soluble derivative of graphene, graphene oxide and linkers molecules that were dispersed in the fiber sizing onto the surface of individual carbon fibers. Here we report mechano-chemical synthesis of a series of functionalized multilayer graphite micro particles able to modify carbon fibers simply dipped to their suspensions in various solvents, including water. The known mechanoactivated chemical exfoliation of graphite by maleic anhydride and maleimide was expanded to hexadecylmaleimide and 1,6-dimaleimidohexane. The new materials were characterized by SEM imaging, X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR), powder X-Ray Diffractometry (XRD), nitrogen adsorption isotherm surface analysis, and Diffuse Light Scattering (DLS). The coatings produced on both sized and unsized carbon fibers are resistant to ultrasonication. The pH-dependent dispersibility in water and particle size, relatively high surface area, presence of the thiol-reactive maleimide group in the material cross-linked with 1,6-dimaleimidohexane are the welcome properties f