Relationship between the Strength of the Boundary Layer of a Binder and the Surface Structure of Carbon Fibers

The relationship between the boundary-layer strength and filler surface structure in suspensions of carbon fibers in an epoxy-resin solution is studied using ideas of fractal analysis. An increase in the fractal dimension of the fiber surface is shown to lead to enlargement of the contact area between components of the considered suspensions. The yield stress of the suspensions depends on the filler particle size and grows as the particle size decreases. Considerable enhancement of interfacial interactions is observed for nanoparticles and is treated to be the nanoadhesion effect. The proposed model enables us to carry out estimations of interfacial adhesion in solid-phase composites based on the results obtained for the suspensions.