Miscible polymer blends have a simple continuous relationship between properties and composition, when amorphous, unlike many immiscible blends whose properties may fall below those of the components. Miscible blends of high-preformance polymers with less expensive polymers consequently offer the advantage of specifying performance levels within wide limits for minimum cost. The goal of this research is to advance the principles, through example, for controlling phase behavior of blends of this type through molecular structural design. In particular, this research focuses on identifying examples of miscible blends of existing or new high-performance polymers, such as polycarbonates, polysulfones, polyacrylates, etc. with less expensive polymers based on commodity monomers like styrene, methyl methacrylate, acrylonitrile, etc. The strategy is to find homo-polymer pairs that are energetically close to the border of miscibility and then use copolymerization to make them usefully miscible via the benefits of intramolecular repulsion effects. A search for such systems must be guided by principles, since the number of compositional variables is too great to randomly explore them all. This work involves application of the latest theories of miscibility and techniques for quantifying interactions in addition to synthesis of targeted polymers or copolymers. In addition to identification of potentially useful materials, this work should answer important basic question aboutintermolecular interactions.
