PHASE-BEHAVIOR OF BINARY-MIXTURES CONTAINING A SELF-ASSOCIATING POLYMER

A simple association model has been developed and used to calculate th e phase diagrams of a self-associating block copolymer/inert homopolym er mixture. It is shown that in this type of system a closed immiscibi lity regime can be observed, even in mixtures without strong specific interactions. A comparison of the model phase diagrams with the known phase diagram of a mixture of the block copolymer poly(styrene-co-buta diene) and polystyrene is satisfactory and leads to the suggestion tha t in this system a closed immiscibility regime is possible at higher t emperatures and a noncritical-critical ''sideways coalescence'' of two miscibility gaps can occur.