This contribution extends the study of the interaction of poly(vinyl butyral) (PVB), containing systematically varying hydroxyl levels, in a ternary crystalline blend system of poly(vinyl butyral)/poly(vinyl alcohol)(PVA)/nylon6(N6). Thermodynamic miscibility of the amorphous phases is indicated for blends of PVB/PVA/N6 in the range of approximately 0.4-0.6 volume fraction of vinyl alcohol (VA) in the blends in which two co-continuous crystalline phases are also present. The miscibility parameter model proved useful in examining potential regions of compatibility/miscibility and indicates that mainly dispersive-polar interactions are responsible for miscibility of the amorphous phases.