Conclusions
-
1.
The activation energies of viscoelastic relaxation and viscous flow of melts of LDPE/HDPE blends of the same composition are the same.
-
2.
The viscosity of melts of blends of linear and branched polyethylenes with low shear stresses is higher and corresponds to the value predicted by the rule of logarithmic additivity for high shear stresses.
-
3.
The shear rate corresponding to the appearance of elastic turbulence increases exponentially with an increase in the proportion of HDPE in the polyethylene blend.
-
4.
The equilibrium shear modulus of the melt can be regulated within broader limits by mixing HDPE and LDPE than by altering the molecular characteristics of the polymer.
-
5.
The Havriliak-Negami equation in principle cannot describe the ratio of the rates of accumulation and dissipation of energy in steady-state shear flow whenP w/2ġgη0 > 0.5 (not the experimentally observed viscosity superanomaly is predicted, i.e.,dσ12/dġg < 0).
-
6.
The first difference of normal stresses in shear flow, calculated with the die swell with the Bagley equation, is close to the experimental results for HDPE melts and HDPE/LDPE blends if the concentration of HDPE > 60%; for LDPE melts and blends containing HDPE < 60%, the best agreement of the predicted and experimental values is attained in calculations with the Tanner dependence.
Similar content being viewed by others
Literature cited
E. E. Yakobson and L. A. Faitel'son, “Viscoelasticity of melts of polyethylene blends,” Mekh. Kompozitn. Mater., No. 1, 146–157 (1990).
F. R. Eirich, “Introduction to the general concepts of rheology,” in: Rheology: Theory and Applications, Academic, New York, Vol. 1 (1956), Vol. 2 (1958), Vol. 3 (1960).
L. A. Faitel'son and E. E. Yakobson, “Effect of mixtures of fillers on the resistance of polymers to extrusion through capillaries and the surface smoothness of the extrudate,” Mekh. Kompozitn. Mater., No. 1, 112–118 (1987).
F. N. Cogawell, Polymer Melt Rheology, New York-Toronto (1981).
C. D. Han, Rheology in Polymer Processing, Academic, New York (1976).
F. Buche, “Influence of shear on the apparent viscosity of dilute polymer solutions and bulk polymers,” J. Chem. Phys.,22, 1570–1576 (1954).
R. Tanner, “The theory of die-swell,” J. Polym. Sci. A-2,8, No. 12, 2667–2078 (1970).
E. B. Bagley and H. I. Duffey, “Recoverable shear strain and the Barus effect in polymer extrusion,” Trans. Soc. Rheol.,14, 519–594 (1970).
E. Brauer, I. P. Briedis, V. I. Bukhgalter, L. L. Sul'zhenko, L. A. Faitel'son, and P. Fidler, “Rheology and molecular structure of polyethylene melts,” Mekh. Kompozitn. Mater., No. 2, 283–293 (1977).
M. S. Jačovič, D. Pollock, and R. S. Porter, “A rheological study of long branching in polyethylene by blending,” J. Appl. Polym. Sci.,23, 517–527 (1979).
A. Santamaria and J. L. White, “Rheological properties, shrinkage and melt spinning instability of blends of linear polyolefins with low density polyethylene,” J. Appl. Polym. Sci.,31, 209–224 (1986).
L. A. Faitel'son and E. E. Yakobson, “Constituents of the complex modulus in periodic shear of a flowing viscoelastic liquid,” Mekh. Kompozitn. Mater., No. 2, 277–286 (1981).
S. Havriliak and S. Negami, “A complex plane representation of dielectric and mechanical relaxation processes of some polymers,” Polymer,8, No. 4, 161–310 (1967).
E. E. Yakobson and L. A. Faitel'son, “The stress-strain state of macromolecular liquids in steady-state shear flow and storage of energy,” Mekh. Kompozitn. Mater., No. 2, 328–336 (1985).
D. Beynon and B. Glide, “Swelling and breaking of polyethylene melt,” in: Problems in Extrusion of Thermoplasts [Russian translation], Moscow (1963), pp. 262–284.
B. Bernstein, E. A. Karsley, and L. I. Zapas, “A study of stress relaxation with finite strain,” Trans. Soc. Rheol.,17, 391–410 (1963).
R. A. Mendel'son, F. L. Finger, and E. B. Bagley, “Die swell and reversible shearing strains in extrusion of polyethylene,” in: Viscoelastic Relaxation in Polymers [in Russian], A. Ya. Malkin (ed.), Moscow (1974), pp. 178–191.
A. A. Askadskii, The Principle of Additivity in the Physical Chemistry of Polymers [in Russian], Moscow (1987).
A. N. Gorbatenko and Yu. S. Lipatov, “Rheological properties of model blends of polyethylene with polystyrene,” Mekh. Kompozitn. Mater., No. 5, 934–937 (1988).
H. Takahashi, T. Matsuoka, T. Ohta, K. Fukumori, T. Kurauchi, and O. Kamigaito, “Enhanced compatibility of SAN and PC in their blends exposed to extremely high shear fields,” J. Appl. Polym. Sci.,36, 1821–1831 (1988).
Author information
Authors and Affiliations
Additional information
See [1] for Communication 1.
Translated from Mekhanika Kompozitnykh Materialov, No. 2, pp. 262–270, March–April, 1992.
Rights and permissions
About this article
Cite this article
Faitel'son, L.A., Yakobson, E.E. Viscoelasticity of melts of polyethylene blends. 2. Mech Compos Mater 28, 186–193 (1992). https://doi.org/10.1007/BF00613327
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00613327