Characterizing Polymer Degradation During Processing using Multi-Detector GPC and Capillary Rheometry
14 February 2018

Melting and molding are regular processes that polymers like polystyrene (PS) and poly(methyl methacrylate) (PMMA) must endure. If the molecular properties of these polymers change as a consequence of the processing, then it is likely that the final properties of the molded product will vary from those expected of the virgin polymer.

This application note describes the molecular and rheological changes that occurred as samples of PS and PMMA were repeatedly extruded through a capillary rheometer, simulating molding. The capillary rheometer was used to measure changes in melt viscosity, while multi-detector GPC was used to characterize changes in molecular weight and structure in the samples after each cycle through the rheometer.