An association model for describing the thermodynamics of polymer blends with strong directionally specific interactions has been applied to poly(ethyl methacrylate-co-methyl methacrylate) (EMA-co-MMA)/poly(p-vinylphenol) (PVPh) blends. Parameters describing interassociation such as the equilibrium interassociation constant (K-A) and the enthalpy of hydrogen bond formation (h(A)) have been obtained from Fourier transform infrared (FTIR) measurements at 165 and 200 degrees C. Both the temperature range of miscibility and the glass transition-composition curve predicted by the model were found to be in good agreement with experimental results. Also, the magnitude of the enthalpic interaction energy derived in the liquid state for this system is similar to that found for analogue liquid mixtures of the corresponding polymers. Model results suggest that entropic contributions are also very important in determining the miscibility of these systems. Thus, entropic contributions unfavorable to mixing were predicted for the EMA-co-MMA/PVPh system, unlike the favorable contributions for the corresponding analogue mixtures.