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Co‐extrusion of polymers with one single screw having a specially devised double channel
Author(s) -
Iwakura Kenji,
Fujimura Toshikazu
Publication year - 1980
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760201504
Subject(s) - extrusion , materials science , composite material , volumetric flow rate , polymer , channel (broadcasting) , flow (mathematics) , polyamide , viscosity , melt flow index , compression (physics) , mechanics , telecommunications , computer science , physics , copolymer
Co‐extrusion by means of only one single screw with a double channel was studied. The effects of the operating conditions, the material properties and the screw geometries on the inter‐channel flow and the output rate were determined. The flow mechanism and the application to the composites with stratified structures were discussed. The inter‐channel flow rate decreased with decrease in the back pressure, the stock temperature, the screw rotational speed and the viscosity difference between polymer melts in both channels. The decrease in the compression ratios of channels, the barrier flight in the compression zone and the sealing at the flight clearance with the polyamide‐packing reduced the inter‐channel flow significantly without a decrease in the output rate. With this method, co‐extrudates with distinctly stratified cross‐sections were prepared. The single screw with double‐channel could be applied effectively to the co‐extrusion of composites with stratified structures such as sheath‐and‐core structures, and it is particularly suitable to distribute the additives heterogeneously or to enclose the waste polymer.