PHASE-BEHAVIOR OF POLY(4-VINYLPYRIDINE) POLY(VINYL ACETATE-CO-VINYL ALCOHOL) BLENDS/

The phase behavior of poly(4-vinylpridine) (P4VP)/poly(vinyl acetate-c o-vinyl alcohol) (ACA) blends has been studied as;a function of ACA co polymer composition. Calorimetric curves for blends of ACA ranging fro m 23 to 53% of vinyl alcohol units show exothermal peaks above the gla ss transition corresponding to phase separation processes. Heats of th e mixing of about 1.5 cal/g have been obtained. A progressive breaking of H-bonds as temperature increases is detected by IR spectroscopy. C loud point curves obtained by optical microscopy measurements depend o n ACA copolymer composition. The binary interaction model has been app lied to this system from cloud point data.