A Study of Entrance Pressure Loss in Filled Polymer Melts

Velichko Hristov 1  and John Vlachopoulos 1
  • 1 Department of Chemical Engineering, McMaster University, Hamilton, Canada

Abstract

The influence of the molecular structure of the polymer matrix and filler loading on the entrance pressure loss of polyethylene/wood flour composites has been investigated in this research by means of a capillary rheometer equipped with an orifice die. The entry flow of talc- and glass-filled polyethylene composites has been investigated as well. It was found that the entrance pressure loss of wood filled polyethylene composites greatly increased with increasing the wood flour loading. Talc and solid glass spheres also increase the entrance pressure loss, however not as much as wood flour. It was also observed that composites based on narrow molecular weight distribution (MWD) resins exhibited larger entrance pressure loss than the broad MWD and branched polyethylene based ones. It was concluded that measurements of the entrance pressure loss reveal some interesting features of the polymer-filler interactions and could provide significant insights in the processing of highly filled polymer melts.

If the inline PDF is not rendering correctly, you can download the PDF file here.

  • [1] Bagley EB: End corrections in the capillary flow of polyethylene, J. Appl. Physics 28 (1957) 624-627.

  • [2] Bagley EB, Birks RM: Flow of polyethylene into a capillary, J. Appl. Physics 31 (1960) 556-561.

  • [3] Dealy JM, Wissburn KF: Melt rheology and its role in plastics processing, Van Nostrand Reinhold (1990).

  • [4] White JL, Kondo A: Flow patterns in polyethylene and polystyrene melts during extrusion through a die entry region: Measurement and interpretation, J. Non-Newt. Fluid Mech. 3 (1970) 41-64.

  • [5] Mitsoulis E, Schwetz M, Münstedt H: Entry flow of LDPE melts in a planar contraction, J. Non-Newt. Fluid Mech. 111 (2003) 41-61.

  • [6] Mitsoulis E, Hatzikiriakos SG: Bagley Correction: The effect of contraction angle and its prediction, Rheol. Acta 42 (2003) 309-320.

  • [7] Feigl K, Öttinger HC: Investigation of die entry flows of polymer melts, Appl. Rheol. 6 (1996) 59-66.

  • [8] Mitsoulis E, Vlachopoulos J, Mirza FA: A numerical study of the effect of normal stresses and elongational viscosity on entry vortex growth and extrudate swell, Polym. Eng. Sci. 25 (1985) 677-689.

  • [9] Dupont S, Crochet MJ: The vortex growth of a K.B.K.Z. fluid in an abrupt contraction, J. Non-Newt. Fluid Mech. 29 (1988) 81-91.

  • [10] Luo XL, Mitsoulis E: A numerical study of the effect of elongational viscosity on vortex growth in contraction flows of polyethylene melts, J. Rheol. 34 (1990) 309-342.

  • [11] Mitsoulis E: Numerical simulation of entry flow of the IUPAC-LDPE melt, J. Non-Newt. Fluid Mech. 97 (2001) 13-30.

  • [12] Cogswell FN: Measuring the extensional rheology of polymer melts, J. Rheol. 16 (1972) 383-403.

  • [13] Shroff RN, Cancio LV, Shida M: Extensional flow of polymer melts, J. Rheol. 21 (1977) 429-446.

  • [14] Binding DM, Walters K: On the use of flow through a contraction in estimating the extensional viscosity of mobile polymer solutions, J. Non-Newt. Fluid. Mech. 30 (1988) 233-250.

  • [15] Chauveteau G, Moan M, Magueur A: Thickening behaviour of dilute polymer solutions in Non-inertial elongational flows, J. Non-Newt. Fluid Mech. 16 (1984) 315-327.

  • [16] Kwag C, Vlachopoulos J: An assessment of Cogswell’s method for measurement of extensional viscosity, Polym. Eng. Sci. 31 (1991) 1015-1021.

  • [17] Laun HM, Schuch H: Transient elongational viscosities and drawability of polymer melts, J. Rheol. 33 (1989) 119-175.

  • [18] Han CD, Charles M, Philippoff W: Rheological implications of the exit pressure and die swell in steady capillary flow of polymer melts. I. The primary normal stress difference and the effect of L/D Ratio on elastic properties, J. Rheol. 14 (1970) 393-408.

  • [19] Bailey RS, Groves DJ: Characterization of finite length composites: Part VI - Rheological studies of materials based on the polypropylene matrix, Pure and Appl. Chem. 69 (1997) 2541-2565.

  • [20] Crowson RJ, Folkes MJ, Bright PF: Rheology of short glass fiber-reinforced thermoplastics and its application to injection molding I. Fiber motion and viscosity measurement, Polym. Eng. Sci. 20 (1980) 925-933.

  • [21] Chan Y, White JL, Oyanagi Y: Influence of glass fibers on the extrusion and injection molding characteristics of polyethylene and polystyrene melts, Polym. Eng. Sci. 18 (1978) 268-272.

  • [22] Guo R, Azaiez J, Bellehumeur C: Rheology of fiber filled polymer melts: Role of fiber-fiber interactions and polymer-fiber coupling, Polym. Eng. Sci. 45 (2005) 385-399.

  • [23] Laun HM: Orientation effects and rheology of short glass fiber-reinforced thermoplastics, Colloid and Polym. Sci. 262 (1984) 257-269.

  • [24] Laun HM: Das viskoelastische verhalten von polyamid-6-schmelzen, Rheol. Acta 18 (1979) 478-491.

  • [25] Liang JZ: Effects of particle size on melt viscoelastic properties during capillary extrusion of glass bead-filled LDPE composites, J. Thermoplast. Comp. Mater. 19 (2006) 703-713.

  • [26] White JL, Crowder JW: The influence of carbon black on the extrusion characteristics and rheo-logical properties of elastomers: Polybutadiene and butadiene-styrene copolymer, J. Appl. Polym. Sci. 18 (1974) 1013-1038.

  • [27] Minagawa N, White JL: The influence of titanium dioxide on the rheological and extrusion properties of polymer melts, J. Appl. Polym. Sci. 20 (1976) 501-523.

  • [28] Hristov V, Takacs E, Vlachopoulos J: Surface tearing and wall slip phenomena in extrusion of highly filled HDPE/Wood flour composites, Polym. Eng. Sci. 46 (2006) 1204-1214.

  • [29] Hatzikiriakos SG, Mitsoulis E: Excess pressure loss in the capillary flow of molten polymers, Rheol. Acta 36 (1996) 545-555.

  • [30] Kim S, Dealy JM: Design of an orifice die to measure entrance pressure drop, J. Rheol. 45 (2001) 1413-1419.

  • [31] Denn MM: Extrusion instabilities and wall slip, Annu. Rev. Fluid Mech. 33 (2001) 265-287.

  • [32] Macosko C.W: Rheology-Principles, measurements, and applications, VCH Publ. (1994).

  • [33] Thomasset J, Carreau PJ, Sanschagrin B, Ausias G: Rheological properties of long glass fiber filled polypropylene, J. Non-Newt. Fluid Mech. 125 (2005) 25-34.

  • [34] Balasuriya PW, Ye L, Mai YW: Mechanical properties of wood flake–polyethylene composites. Part I: Effects of processing methods and matrix melt flow behavior, Composites, Part A, 32 (2001) 619-629.

  • [35] Li TQ, Wolcott MP: Rheology of HDPE - wood composites. I. Steady state shear and extensional flow, Composites, Part A 35 (2004) 303-311.

  • [36] Han CD: Multiphase flow in polymer processing, Academic press, (1981).

OPEN ACCESS

Journal + Issues

Search