Polymer plug-shaped

We developed an experimental procedure that can be applied to highly viscous polymer blends. In the DSM micro-extruder [6], polymers are blended in the melt, at the desired temperature and pressure, and injected into a small capillary tube which is immediately sealed with a floating plug. This capillary cell is placed in a small window autoclave and a laser beam enters the capillary cell at the lens-shaped bottom end. The intensity of the light scattered by the polymer system is recorded at two scattering angles (as a function of pressure and temperature). 

The rough surface of ceramic filter media promotes adsorption of particles and bridging. Sintering of chamotte with a binder results in large blocks from which filter media of any desired shape can be obtained. Using synthetic polymers as binders, ceramic filter media that do not contain plugged pores are obtained. 

As a starting point, consider the behavior of the fluid after extrusion. Immediately after extrusion, the fluid experiences the die swell phenomenon, where the velocity profile flattens. Ultimately, when the fiber solidifies, the velocity profile will be flat (i.e., plug flow). In between, a velocity profile will possibly be first formed and then distorted by solidification at the fiber exterior. Even if the profile becomes fully developed, however, it will not have a parabolic shape but rather will have a blunted form because of the polymer s non-Newtonian fluid behavior. In essence, then, the fiber in the post-extrusion-solidification region will have a velocity profile that can be closely approximated by assuming plug flow (i.e., a constant V across the fiber cross section). 

The deformation of molten polyethylene may take place in either constrained or nnconstrained systems. The former is exemplified by flow in a channel, such as that encountered in an extmder or an injection molding die. The latter involves elongation of the melt without the benefit of walls to constrain its shape, typified by film blowing or the drawing of an extrudate to form a fiber. Flow in a eonstrained system involves shear deformation whenever the polymer adheres to the walls. When adhesion to the wall fails, slip/stick or plug flow oeeurs, neither of which is desirable in the ordinary eourse of polyethylene pro-... 

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