Influence of a Feed‐Opening Section on the Output and Selected Mechanical Properties of a Poly(Vinyl Chloride) Extrudate

Abstract

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. C

The Effect of Blowing Agents on the Effectiveness of Poly(vinyl Chloride) Extrusion

“…Sikora and B. Samujło with regard to the extrusion of non-cellular PVC [11]. The increase in the polymer flow rate due to a higher content of the blowing agent in the polymer mainly results from a lower flow resistance of the PVC being extruded in the flow channels and extruder head die.…”

“…Following the above pattern, we measured the direct parameters of the polymer using three chemical blowing agents with different decomposition properties. The indirect parameters were investigated using generally know dependencies taken from the literature [1,11]. …”

“…As demonstrated in the studies [1,8,10,16], the processing conditions as well as design of the extruder's plasticizing unit are here of vital importance here; nonetheless, it must be observed that the above studies discuss heating, compression and conveyance of solid, and not cellular plastics. The problem of impact of the plasticizing unit, feed opening, barrel and extruder screw designs on the effectiveness of extrusion has been investigated in the studies [6,11]. However, these studies focus on the extrusion of solid plastics and, hence, do not offer any universal and comprehensive relationships or solutions that could also be applied to cellular extrusion.…”

Studium wytłaczania polietylenu z dodatkiem nanorurek haloizytowych. Cz. I. Charakterystyka procesu wytłaczania

“…Dążenie do uzyskania tworzyw i kompozytów polimerowych o lepszych właściwościach, jak również uwarunkowania prawne, są powodem dodawania do tworzyw różnych napełniaczy oraz dodatków. Wpływają one na właściwości przetwarzanych tworzyw i kompozytów, wymuszając zmianę parametrów przetwórstwa oraz geometrii układu uplastyczniającego wytłaczarki, celem zapewnienia właściwej efektywności procesu wytłaczania 9,10) .…”

Research on the Influence of Blowing Agent on Selected Properties of Extruded Cellular Products

“…Modification of cable coatings and research on the extrusion process conducted in the Department of Polymer Processing at Lublin University of Technology [3][4][5][6][7][8][9][10][11] are focused especially on manufacturing coatings from cellular plastics, what results in the reduction of plastic purchase costs, energy costs of the process and transportation costs. At the same time, this results in the replacement of conventional extrusion coating by the cellular extrusion process [11][12][13][14]. The obtained extruder product may have a fully solid or cellular structure, it may be cellular in its entirety, or have a cellular core and a solid topcoat ( Fig.…”