MISCIBILITY OF REGULAR MULTIBRANCHED POLYSTYRENE WITH LINEAR POLYSTYRENE

Differential scanning calorimetry (d.s.c.) measurements on the 50/50 b lends of well-defined multibranched polystyrenes and linear polystyren es were carried out to investigate the miscibility between polymer com ponents having the same constitutional repeating units but different m olecular architectures. Multibranched polystyrenes with different bran ch number and length were prepared by the radical polymerization of po lystyrene macromonomers of different molecular weights possessing a di fferent polymerizable end group, i.e. a vinylbenzyl end group and meth acryloyl end group. D.s.c. curves showed one or two thermal transition s corresponding to the glass transitions depending on both the branchi ng architecture of the multibranched polystyrene, namely poly(macromon omer)s, and the molecular weight of the linear polystyrenes. The misci bility between the poly(macromonomer) and the linear polystyrenes decr eased with increase in both branch number of poly(macromonomer)s and t he molecular weight of the linear polystyrene. The miscibility increas es with increase in the branch length but was not much influenced by t he chemical structure of the central backbone of the poly(macromonomer )s. These results indicate that the miscibility in the athermal binary multibranched-linear polystyrene blends is influenced by the branchin g architecture, and the blends locate near the miscible/immiscible bou ndary.