CASTING SOLVENT EFFECT ON CRYSTALLIZATION BEHAVIOR OF POLY(VINYL ACETATE) POLY(ETHYLENE OXIDE) BLENDS - DSC STUDY

Poly(vinyl acetate) (PVAc)/poly(ethylene oxide) (PEG) blends were prep ared by casting from either benzene or chloroform. The solvent effects on the crystallization behavior and thermodynamic properties of the b lends were studied by the differential scanning calorimeter ( DSC). Tw o grades of PEO with different molecular weights (PEO200 with M(w) = 2 00,000 g/mol and PEO2 with M(n) = 2000 g/mol) were used in this work. The thermal analysis revealed that the blends cast from either benzene or chloroform were miscible in the molten state. The crystallization of PEO in the benzene-cast blends was more easily suppressed than it w as in the chloroform-cast blends. Furthermore, the benzene-cast blends showed a greater negative value of Flory-Huggins interaction paramete r than those cast from chloroform in the PVAc/PEO200 polyblend system. It was supposed that the benzene-cast blends had more homogeneous mor phology. (C) 1997 John Wiley & Sons, Inc.