Capillary rheometry was used for measurement of the high rate steady-state flow properties of micro-filled high- density polyethylene (HDPE) melts, and the effects of the test geometry were investigated. Attention was paid to the influence of the die diameter. The micro-compounds examined had the same filler content (10 vol.% in the melt state), but differed in the nature and geometry of filler (glass beads, discontinuous glass fibres and talc). A die diameter effect on the pressure drop localized at the die entrance was clearly observed for the unfilled HDPE; for the micro-filled melts, this effect was either enhanced or considerably reduced, depending on the type of filler (opposite effects were induced by glass beads and by glass fibres). A die diameter effect on the macroscopic shear viscosity response was noticed only for the melts filled with particles with relatively high aspect ratio (glass fibres and talc platelets).
Measurement of the high rate flow properties of filled HDPE melts by capillary rheometer: Effects of the test geometry
BALDI, Francesco;
2014-01-01
Abstract
Capillary rheometry was used for measurement of the high rate steady-state flow properties of micro-filled high- density polyethylene (HDPE) melts, and the effects of the test geometry were investigated. Attention was paid to the influence of the die diameter. The micro-compounds examined had the same filler content (10 vol.% in the melt state), but differed in the nature and geometry of filler (glass beads, discontinuous glass fibres and talc). A die diameter effect on the pressure drop localized at the die entrance was clearly observed for the unfilled HDPE; for the micro-filled melts, this effect was either enhanced or considerably reduced, depending on the type of filler (opposite effects were induced by glass beads and by glass fibres). A die diameter effect on the macroscopic shear viscosity response was noticed only for the melts filled with particles with relatively high aspect ratio (glass fibres and talc platelets).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
