Blend Morphology Development During Melt Flow:Correlation of a Model Concept Based on Dynamic Phase Volume With Practical Observations

摘要

An approach is first developed that can be used to identify the global morphology of an immiscible two-phase polymer-polymer blend under shear flow.The basis for the modeling is the concept of a dynamic phase volume;this is based on relative abilities of the respective phases to flow when under stress,and determinde by the actual phase volume fraction and the viscosity ratio between phases.One result of the modeling is a schematic diagram providing guidelines for morphology development during melt processing in a nonuniform stress field.Bisphenol A polycarbonate(PC)/ABS blends were studied as an immiscible system,using variations of component ratio and viscosity ratio at constant composition.Blend morphology was characterized by scanning electron microscopy and solid-state dynamic mechanical spectroscopy.Model predictions correlate well with experimental observations of the frozen-in solid-state morphology following injection molding.Discussion also cover the utility of the model for blend design and limitations of the modeling approach.