Viscoelastic Phase Separation and Interface Assisted Crystallization in a Highly Immiscible iPP/PMMA Blend

Polymer blends with dynamic asymmetry have attracted much interest recently. In this study, we report a more typical case where the dynamically asymmetric system is highly immiscible. We find that there is a transient network growth and phase inversion for the slow minor component. The network structure shows a hierarchical growth behavior, which is the result of competition between a slow relaxation-controlled concentration growth on local scale and a fast hydrodynamic growth on large scale. When phase separation couples with a subsequent crystallization, the interfacial boundary may assist lateral crystallization and irregular spherulites would grow epitaxially around the amorphous component-rich domains. The interface may play the role of substrates for heterogeneous nucleation. These phenomena may help us with morphological control in material processing.