A fundamental study of polymer melt devolatilization. IV: Some theories and models for foam‐enhanced devolatilization

Some model experiments on polymer melt devolatilization (DV) conducted in our laboratories have been previously reported. Here, we examine some theories and propose some mathematical models in pursuit of an explanation of these experimental observations. Included are bubble nucleation and free volume theories as well as continuum models for bubble growth in quiescent fluids and fluid flow in rolling pools without bubbles. A modification of Harvey's cavity model seems to explain the behavior of foam formation in DV, at least qualitatively. Denson's cell model for bubble growth fits the separation data under vacuum. A simple exponential model for overall separation fits the separation data at atmospheric pressure (entrained DV).