Phase diagrams for poly(n-hexyl methacryrate) blends with a series of
styrene-co-vinylphenol polymers have been mapped using light-scatterin
g techniques. These are compared to theoretical phase diagrams calcula
ted using an association model that incorporates the various interacti
ons in hydrogen-bonded polymer systems. The thermodynamics of these bl
ends is strongly affected by the competition between the self-associat
ing and interassociating hydrogen bonds and the unfavorable dispersive
interactions. The balance of these competing factors controls the tem
perature and composition of phase separation. The results of the theor
etical predictions are found to be in good accord with the experimenta
l phase diagrams. They also help in explaining the molecular weight in
dependence and the skewness (asymmetry) of the phase diagrams.