Miscibility and phase separation in poly(vinyl methyl ether)/poly(bisphenol A hydroxy ether) blends

Amorphous blends of poly(vinyl methyl ether) (M sub w = 63 000 and M sub n = 37 000) and a copolymer of bisphenol A and epichlorohydrin (M sub w = 50 400 and M sub n = 18 000) were found to be miscible over the complete range of compositions at temperatures < 420K. At higher temperatures, blends separate into two phases, giving a LCST-type phase diagram. Heats of demixing and excess heat capacity of a 50:50 blend have also been measured by DSC. The results have been interpreted in terms of the equation-of-state theory and compared with predictions of a recent model proposed by ten Brinke and Karasz for blends which have direction-specific interactions. 20 ref.--AA