Shear-Induced Orientation of Cocontinuous NanostructuredPolymer Blends.

Cocontinuous nanostructured blendsof semicrystalline polymers tend to align along a preferential directionwhen subjected to steady flow. We investigate the flow induced changesexperienced by cocontinuous blends using transmission electron microscopyand small-angle X-ray scattering and we demonstrate that shear flowinduces a preferential direction while preserving a cocontinuous structure,which is oriented along the flow direction. In parallel, we studythe viscoelastic properties of the aligned morphology by linear oscillatoryshear above the melting temperature of the blend components and observea liquid-like behavior at short times. Upon annealing at high temperature,the aligned morphology relaxes back to the original isotropic structurewith a solid-like viscoelastic behavior. [ABSTRACT FROM AUTHOR]