Monitoring Polymer Phase Transitions by Combining Rheology and Raman Spectroscopy

The use of rheology and Raman spectroscopy in a coupled system for obtaining comprehensive insight into materials behavior is presented. Coupling rheology with Raman spectroscopy provides direct correlation of molecular composition and structure to the observed mechanical properties. The approach is extremely useful for studying phase transition behavior, such as the crystallization behavior of polymer melts during processing. It can also provide insight for in situ characterization and monitoring, which can be challenging when working with on-line techniques because only relative flow fields are characterized. Finally, the coupling of the two techniques gives researchers the advantage of maximizing and synchronizing the information gathered from a single measurement, as compared to sequential measurements, as well as enabling the observation of transient information on their materials during fast processing conditions. In this article, we present the experimental details of a rheo-Raman approach and then apply it to polymer melting.