Study of the miscibility of poly(styrene–co-4-vinylbenzoic acid) with poly(ethyl methacrylate) or with poly[ethyl methacrylate–co-(2-N,N-dimethylaminoethyl) methacrylate] by inverse gas chromatography

Poly(styrene) is immiscible with poly(ethyl methacrylate). The introduction of a small amount of 4-vinylbenzoic acid units along poly(styrene) chains (PS–VBA) enhanced its miscibility with poly(ethyl methacrylate) (PEMA) or with poly[ethyl methacrylate–co-(2-N,N-dimethylaminoethyl) methacrylate] (PEMA–DAE), as observed from the appearance of a single composition dependent glass transition temperature for each binary system using inverse gas chromatography. The negative values of the apparent polymer–polymer interaction parameter, χapp23, determined with different families of molecular probes, for three blend compositions and over a range of temperature confirm quantitatively the miscibility of these blends. The χapp23values for PEMA(PS–VBA) and (PEMA–DAE)–(PS–VBA) blends are dependent of the chemical nature of the probes, the temperature and the blend composition.