In this paper, a poly(vinyl acetate) (PVAc) adhesive in the form of a film was considered to be a composite. Its mechanical properties changed with filler addition owing to the interactions at the polymer/filler interface. The experimental results were fitted with various theoretical and empirical equations that describe the dependence of mechanical properties on filler volume fraction. In this way, the coefficients calculated from the mostly empirically broadened equations for the case of adhesion between the matrix and filler gave the opportunity to determine the interactions between the PVAc matrix and various fillers quantitatively.