Interfacial activity of a poly(styrene-g-ethylene oxide) copolymer in immiscible polymer blends

The interfacial activity of a comblike poly(styrene-g-ethylene oxide) copolymer is studied in different immiscible polymer blends. The miscibility of the backbone and branches of the copolymer in the blend components is varied. The blend components investigated are polystyrene/poly(ethylene oxide), polystyrene/poly(methyl methacrylate), and poly(phenylene oxide)/poly(methyl methacrylate). Results from scanning electron microscopy, SEM, dynamic mechanical spectroscopy, DMTA, and differential scanning calorimetry, DSC, show that small amounts of copolymer locate at the interfaces between the blend components and increase the interfacial area. The effect is obvious when there are interactions between both of the blend components and the backbone and branches of the copolymer.