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

A simple association model has been developed and used to calculate the phase diagrams of a self-associating block copolymer/inert homopolymer mixture. It is shown that in this type of system a closed immiscibility 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-butadiene) and polystyrene is satisfactory and leads to the suggestion that in this system a closed immiscibility regime is possible at higher temperatures and a noncritical-critical ''sideways coalescence'' of two miscibility gaps can occur.