ABSTRACT
Foam formation in the molten polymer by either reducing pressure or purging with inert gases allows substantial increase of interfacial mass transfer area to maximize separation efficiency. In many industrial processes the volatile components are continually removed from molten polymer through foam formation, foam growth, and rupture into a contiguous gas phase. Diffusion and melt rheology become the controlling factors for foam growth. A modified version of the devolatilizer was established for further foaming investigations. Bubble growth is a rate process, and its limit is determined by thermodynamic parameters. Many research efforts have been devoted to the growth of a spherical gas bubble in a liquid in the absence of flow. Foaming activity lasted from a few seconds to a few minutes, depending mainly on system parameters. One could speculate that a bubble population balance is a good approach to describe foaming in the rolling pool at one atmosphere, with a constant bubble birth and death rate depending on rpm.
