Dynamic mechanical behaviors of binary and ternary particulate composites are investigated to test for the influence of the nature of a polymeric adduct, i.e., maleated styrene ethylene-co-butylene styrene (SEES) or styrene-co-methacrylic acid (SAMA) copolymers, at the polystyrene (PS)/glass-beads interface on the mechanical coupling and the adhesion quality between phases. Then, to separate the influence of these two causes, a rigorous modeling of the viscoelastic properties of ternary particulate composites is proposed. Thus, by comparing experimental and theoretical data, it is concluded that the rubbery and rigid adducts both induce a change in the magnitude of the mechanical coupling between phases. it is shown, however, that the SAMA coupling agent exhibits a better compatibility with the PS matrix than that of maleated SEES. This could result from the difference in the wt % of styrene segments between these two copolymers.