Plastification and Homogenizing Sections

The plastification process is initiated the polymer contacts the hot inner wall of the barrel and/or by mechanical stress of the solid particles in the kneading elements. The melting process is continued by the introduction of mechanical energy into the melted product via shear stresses and/or heat conduction from the melt to the as yet un-melted product. The detailed design of the plastification section depends on the product. 

The efficiency of a forward kneading and plastification section depends greatly on the operating conditions of the extruder. The elements in this section may only be partially full, and entrained gas can therefore pass downstream which increases the risk for the polymer to not melt completely (Fig. 11.6). 

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