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Extrudate properties are largely shaped by the thermal and rheological phenomena occurring in the plasticizing systems of extruders, the channels and die of the extrusion head, the calibrator, and to a lesser extent, in other parts of extrusion lines. These phenomena are affected by barrel and screw design, the type of material being processed, its granulometry, and the technological parameters of the extrusion process. Studies were carried out on the dependency of the output and selected mechanical properties of a plasticized poly(vinyl chloride) (PVC) extrudate on rotational speed of the screw, the width of the feed opening, and the length of the pellets of input polymer. It was found that the parameters tested were affected to the largest extent by the screw-rotational speed. A fivefold increase in screw-rotational speed resulted in a few hundred percent increase in the output and a several dozen percent increase in the yield strength of the extrudate, with the highest value obtained for pellets whose length was close to their diameter. Reduction of the width of the feed opening from 1.0 to 0.6 D resulted in a slight increase in the yield strength and tensile strength. High output, yield strength, and tensile strength values of PVC are most readily achieved at high screw-rotational speed, the smallest width of the feed opening, and the length of pellets close to their diameter.
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