Wesley R. Burghardt, Northwestern University
August 28, 2014
810 South Clinton Street, Chicago, IL 60612
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Synchrotron X-ray Scattering Studies of Polymer Melt Structure During Uniaxial Extensional FlowSingle
The non-Newtonian flow characteristics of polymers and other complex fluids is intimately related to the ability of flow fields to perturb molecular or meso-scale structure. Consequently, modern research emphasizes the molecular or microstructural origins of complex rheological behavior. Further, technological applications of polymers often rely on flow-induced structural changes (i.e. molecular orientation) that affect the resulting material properties. This talk will describe efforts to establish in situ x-ray scattering as a tool to probe the structure of complex polymer fluids under flow. High brilliance synchrotron sources coupled with advances in detector technology enable real-time studies of transient structural dynamics, which can, in many cases, be directly linked to macroscopic rheological behavior. The presentation will particularly focus on recently developed capabilities to study structure developments in polymer melts subjected to well-defined uniaxial extensional flow. The instrument is based on the commercially available ‘SER’ extensional flow fixture, which has been incorporated into a home-built convection oven designed for operation in a synchrotron beam line environment, providing access for incident and scattered x-ray beams. Applications to be discussed include flow-induced orientation in ordered SEBS triblock copolymer melts, and measurements of flow-induced crystallization in isotactic poly(1-butene).
Jun 17, 2019
Jun 17, 2019