Glass beads were encapsulated by grafted polymers : polybutylacrylate and polystyrene. Grafting was performed by the polymerization initiated from the particle surface with preliminary adsorbed polyperoxide initiator. Grafting procedure and properties of grafted film were studied using model substrates : powders, plates, and wafers by wetting technique and SEM. Conditions of grafting affect the film structure. They are porous, and due to some sort of pores the wetting liquid is able to penetrate into covering and reach the substrate. Model epoxy composites were prepared with covered glass beads. The coverings allowed a decrease of adhesion between the matrix and bead surface to detect acoustic emission caused by the debonding process. The dependence of debonding stress from covering the structure and nature was studied.