Rheological properties of polypropylene/high-density polyethylene blend melts. I. Capillary flow properties
Article first published online: 10 MAR 2003
Copyright © 1991 John Wiley & Sons, Inc.
Journal of Applied Polymer Science
Volume 42, Issue 2, pages 467–480, 20 January 1991
How to Cite
Fujiyama, M. and Kawasaki, Y. (1991), Rheological properties of polypropylene/high-density polyethylene blend melts. I. Capillary flow properties. J. Appl. Polym. Sci., 42: 467–480. doi: 10.1002/app.1991.070420219
- Issue published online: 10 MAR 2003
- Article first published online: 10 MAR 2003
- Manuscript Accepted: 8 MAR 1990
- Manuscript Received: 31 OCT 1989
Three kinds of isotactic polypropylenes (PP) with different melt flow indexes (MFIs) were melt-blended with three kinds of high-density polyethylenes (HDPE) with different MFI using a screw extruder, and the morphologies and capillary flow properties such as flow curve, entrance effect, Barus effect, and melt fracture were studied. When HDPE contents were 70 wt % or above and PP particles formed the disperse phase, the size of the particles decreased with decreasing viscosity of PP. When HDPE contents were 30 wt % or below and HDPE particles formed the disperse phase, the size of the particles was minimum when the viscosities of PP and HDPE were similar. The die swell ratios of the blends were higher than those of the components. On the other hand, the entrance correction coefficients of the blends were intermediate between those of the components. There was no correlation between the die swell ratio and the entrance corretion coefficient. Therefore, it is not always appropriate to regard the entrance correction coefficient as a measure of melt elasticity in the case of inhomogeneous polymer systems such as PP/HDPE blend.