Analysis of Palierne's emulsion model in the case of viscoelastic interfacial properties

The quantitative understanding of rheological experiments on compatibilized binary polymer blends requires the consideration of viscoelastic interfacial properties. The Palierne model offers these capabilities but a systematic analysis has not been performed yet. Starting from the Palierne model containing a Maxwell ansatz for complex interfacial shear or dilatational moduli and which considers a particle-size distribution function, we find that this model combines parameter and material functions in an ambiguous way. Consequently, a simplified version of the model-frequency-independent interfacial moduli and monomodal particle-size distribution-was introduced. Formulas have been derived for the relaxation times, the form relaxation time, and one additional still longer time which is associated with viscoelastic interfacial properties. We have found a good agreement between the predictions of the model and experimental data as well as the characteristic times in the relaxation time spectrum and the derived time constants for a PS/PMMA blend compatibilized with different amounts of a corresponding symmetric block copolymer. These results reveal that from the rheological point of view, the interface is of almost elastic nature, either shear or dilatational. (C) 1999 The Society of Rheology. [S0148-6055(99)01406-6].