RheoDSC Analysis of Hardening of Semi-Crystalline Polymers during

The crystallization of semi-crystalline polymers is often ana-lyzed by rheometry and calorimetry. By rheometry the viscosity evolution during crystallization can be followed, whereas from a calorimetric measurement, the evolution of the degree of crystallinity can be calculated. The time evolution of these ma-terial properties is valuable input for polymer processing simu-lation software and in order to combine the data in a reliable manner, hardening curves are used as a characterization tool. Such a hardening curve correlates the relative increase of the viscosity resulting from crystallization, to the advancing de-gree of crystallinity. In this study, these are extracted from si-multaneous measurements on one sample using a RheoDSC device. The RheoDSC technique allows for the direct combina-tion of the rheological and calorimetric signal without the need of combining separate stand-alone measurement results. In this study, isothermal crystallization experiments are used to discuss the benefits of this approach. This will lead to the re-commendation that measuring the hardening effect in steady shear measurements at very low shear rates in a direct com-bined RheoDSC setup is the most reliable method to compile unambiguously a material specific hardening curve for semi-crystalline polymers.