Analysis of the Phase Structure of Molten Polymer Blends using a Modified Gramespacher-Meissner Model
Sprache des Vortragstitels:
85th Annual Meeting of the Society of Rheology
Sprache des Tagungstitel:
Oscillatory shear rheometry is a powerful tool for the detection of phase separation in molten polymers and thus for the investigation of the solubility of each component in a mixture. This is due to additional long-time relaxation processes, which are caused by the deformation of the interface between different phases.
A potential error source in such measurements is phase separation induced by crystallization during sample preparation, which might prevail througout the experiment. Therefore we designed an experimental set-up where the compounded melt is directly injected into the rheometer, thus avoiding any crystallization between mixing and the measurement.
In case of complete miscibility, the relaxation time spectrum obtained from the measured dynamic moduli will correspond with the spectrum calculated from the combined molar mass distributions of the components. Otherwise, the occurrence of phase separation will be reflected by a discrepancy between these spectra. Using the model of Gramespacher and Meissner, valuable information about the phase structure can be gained from this discrepancy. However, a modification to this model is introduced in order to describe the properties of the investigated blends more accurately.