Miscibility and enthalpy relaxations in polysulfone—Carboxylated polysulfone blends

Abstract Phase behavior in polysulfone‐carboxylated polysulfone (PSf‐CPSf) blends was studied by glass transition observations in conjunction with enthalpy relaxation technique. Miscibility in all proportions was detected in blends where CPSf has a degree of carboxylation (DC, i.e. number of carboxyl groups per repeat unit) less than about 1.3. Partial miscibility was detected in blends for DC > 1.4 and up to DC = 1.9, probably as a result of decreasing intermolecular interactions with increase in DC.