Optimizing hydrogen-bonding miscible binary polymer blends made by concentrated emulsion polymerization

Polystyrene/poly (n-butyl methacrylate) blends were prepared by concentrated emulsion polymerization using (2-hydroxy ethyl) methacrylate and n-butyl methacrylate as hydrogen-bond donor and acceptor respectively. Two concentrated emulsions of styrene/(2-hydroxy ethyl) methacrylate and n-butyl methacrylate monomers were prepared separately, and mixed mechanically after partial polymerization. The products thus obtained consisted of compact particles. The specific formation of hydrogen bond between poly [styrene-co- (2-hydroxy ethyl) methacrylate] with poly (n-butyl methacrylate) were studied by transmission electron microscope and dynamic mechanical thermal analysis. The results showed that the miscibility is induced via hydrogen bonding between the hydroxyl group and the carbonyl groups and that hydrogen bonding plays an important role in the compatibilization of the PS/PBMA blends. The TEM micrographs also showed that the PS/PBMA blends are partially inhomogeneous on a scale of 50 nm, and only a single glass transition temperature was found by DMTA for the PS/PBMA blends containing more than 3.0 ml of (2-hydroxy) methacrylate /100 ml styrene.