Interrelation Among Feedstock form, Product Requirements, Equipment Type, and Operating Parameters in Polymer Mixing Processes

Because of the high viscosity (>l00 N·s/m2)that is characteristic of polymer melts, a significant amount of viscous heat can be generated in flows that are subjected to high shear rates. Moreover, polymers have low thermal conduc- tivities, insuring that high shear operations result in an increase in the tempera- ture of the polymer. Because polymers have limited thermal stabilities, processing techniques are limited to low shear operations or regions of limited high shear. Such limited high shear regions usually involve the flow of a thin polymer melt over a large surface area for maximum heat transfer.