MISCIBILITY OF POLY(ETHYLENE OXIDE) AND POLY(STYRENE-CO-ACRYLIC ACID) BLENDS

The miscibility for blends of poly(ethylene oxide) (PEO) with poly(styrene-co-acrylic acid) (SAA) was examined as a function of the comonomer content of the copolymer. PEO was found to be miscible with SAA copolymers having an acrylic acid content higher than 7 mol %. The segmental interaction parameters were determined by combining the equilibrium melting point depression and a binary interaction model. These values suggest that both the specific interaction between ethylene oxide and acrylic acid segments and the intramolecular repulsive force in SAA copolymer are responsible for the miscibility. The minimum acrylic acid content in SAA for the blend to be homogeneous was predicted to be 7.7 mol % from the binary interaction model and the calculated values of segmental interaction parameters. © 1990, American Chemical Society. All rights reserved.