Melting of polymer blends in co-rotating twin screw extruders - Part II: Theoretical derivations

Part II of the publication describes a model for calculating the melting of polymer blends which has been implemented in the SIGMA simulation software for the design of co-rotating Min screw extruders. The model is based on t he findings discussed in Part I and makes it possible to calculate the temp erature progression in the solids conveying section and during the subseque nt melting process for binary incompatible polymer combinations. the two ma terial components are observed in parallel during the melting process, and the respective degrees of melting over the length of the screw are calculat ed. The properties of the melt phase, which forms from both components, are calculated with mixing rules implemented in the program. The calculations supply the melting profiles for both components, thereby permitting a compr ehensive analysis of the melting of binary polymer combinations. The result s additionally form the basis of a calculation to estimate the morphology d evelopment of polymer blends in the melting section of the extruder. Part III of the report looks into a means of investigating the melting of b inary polymer combinations, and the results of experimental investigations into polypropylene/polamide blends are discussed. The simulation calculatio ns are compared with the results of experimental studies in order to verify , the model presented in this part of the publication.