Interphase development in a three-component polymer system with asymmetric mobility

Abstract

We report a study on the interphase evolution in a systemcomposed by three polymeric components withmarkedly different mobility distributed between two layers. One of the layers is a low-Tg blend containing a low molecular weight polystyrene (PS) as a plasticizer (low-M PS) and PS chains with much higher molecular weight (high-M PS). The counterpart is a high-T g layer composed by polyphenylene oxide. The system was annealed at several temperatures between Tg of the polymer layers and the subsequent interphase development probed by optical sectioning with confocal Raman microspectroscopy. The profiles obtained revealed the existence of two diffusion fronts that advance in opposite directions, both showing a similar response with time and temperature. These fronts act as well-defined boundaries that structure the interphase into three well-defined regions with almost constant PS volume fraction. We discuss this particular phenomenology proposing a simple diffusion model that describes the main interphase features.