The selection of the method determined by the condition of the material, the volume of end product required, and the sensitivity of the material to breakdown during shear.
Powders are dry, finely ground plastics and their ingredients.
Plastic are often mixed with glass, carbon, or metals fiber to increase plastic materials strength and stability. PVC plastic is rigid and must be mixed with lubricating additives called plasticizer to make it flexible. The high speed impeller mixer, illustrated in Figure 4-1, is used for dry blending powdered resins, such as PVC with its plasticizer and other additives. The mixer consists of an enclosed container with a higher speed impeller mounted at the bottom. An impeller is similar to the rotating blades of a helicopter.