Morphology development in polymer blends produced by chaotic mixing at various compositions

Whereas blending devices commonly entail complex flow fields and internal geometries, chaotic mixing can be instilled by simple periodic motion of bounding surfaces in simple devices. Breakup and coalescence of spatially expansive structures in components can give blends with a wide variety of morphologies. In this study, polystyrene and low density polyethylene were used as model components to study the effect of composition and processing time on gradual morphology development in immiscible binary blends. Inspections of samples disclosed attainable morphologies and also how transitions between morphologies occurred. Novel findings included blends with encapsulated fibers, abundant platelets, and two distinct morphologies having single phase continuity. Additionally, interpenetrating blends formed over a broad compositional range. Results suggest that chaotic mixing is a useful tool for studying relationships among processing conditions, morphology development, and blend properties and may serve as a means to more deliberately obtain target morphologies.