Since the screw edge of the screw pushes the material forward, it is characterized by continuous shearing of the stream, and then the extruder has a second type of wear under normal operating conditions, that is, the “shear wear” of the screw to the stream. The extent of this “shear wear” is proportional to the viscosity of the stream, in addition to the proportion of the added components such as the enhancer and filler in the stream. Due to the copolymerization reaction extrusion, there is generally no or very little additional reinforcing agent and filler added in the stream, but the viscosity of the material is relatively high, and the superimposed shear wear contradiction and the compound modified extrusion phase The comparative performance is weak, so contrary to the “matched wear” situation of the first category above, the “shear wear” of the screw in the reaction extruder is less pronounced than that of the conventional compound modified extrusion.
Some polymer materials will release a certain corrosive gas during the process of thermal plasticization or reaction exotherm. The corrosive atmosphere will corrode the barrel and screw of the extruder. This is the condition for analyzing the conditions of the screw of the barrel. An important factor that cannot be ignored. Fortunately, for example, in the “bulk copolymerization” continuous reaction extrusion of polyoxymethylene, there is substantially no escape of volatile corrosive gases, so the corrosion of the working surface of the barrel screw can be discussed in depth without working conditions.