Breakup of silica agglomerates in corotating twin screw extruder Modeling and experiment

Extensive experimental studies on silica agglomerate breakup during compounding with polymer melts of varied viscosities and polarities on a modular corotating twin-screw extruder were conducted. In order to avoid a subjectivity of the result, because of small size particles involved, silica agglomerates had been characterized by measuring their mass typical values. Increasing the screw velocity, melt viscosity, and silica concentration were found to increase the silica agglomerate breakup. The effect of these parameters on agglomerate breakup was rated as follows: silica concentration > polymer viscosity ¡Öscrew revolutions per minute (rpm). An excellent correlation between silica agglomerate breakage and power input was also found. In line with the experimental data and dispersion process, a composite modular kinetic style for analyzing silica agglomerate breakup during compounding in a corotating twin-screw extruder was analyzed. The kinetic constants of breakup and reagglomeration of silica agglomerates had been calculated in line with the stresses put on the agglomerates and their cohesive power. These constants for silica agglomerates were found to be not different at substantial concentrations significantly. The latter was in contrast to experimental info from available literature on compounding of calcium carbonate with polypropylene where in fact the increased reagglomeration kinetic constants of calcium carbonate in comparison to those of breakup performed a major position in the agglomerate breakup. Evaluation of the experimental and calculated plastic sheet extrusion results on the silica agglomerate size development during compounding with polymer melts indicated an acceptable arrangement between them at superior rotational speeds.

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