Rheological Behaviour of a Thermotropic Liquid Crystal Copolyester: Hydroxybenzoic Acid / 2,6-Hydroxynaphthoic Acid (Hba/Hna)

  • F. Cocchini
  • M. R. Nobile
  • D. Acierno


The rheology of the all-aromatic copolyester thermotropic liquid crystal 73/27 HBA-HNA has been studied over a large interval of shear rates. At small shear rates the transient behavior has been analyzed with a cone and plate rheometer. The shear stress and the first normal stress difference have been found to scale with the strain. Steady values for both viscosity and first normal stress difference have been obtained. The steady shear viscosities have been correlated to capillary data at higher shear rates. Three zones can be found in the steady viscosity vs shear rate curve: a shear thinning region at small shear rates, an almost newtonian region, and a second power-law region at higher shear rates. In the shear rate interval studied with the cone and plate rheometer the steady first normal stress difference remains positive.


Shear Rate High Shear Rate Hydroxybenzoic Acid Normal Stress Difference Liquid Crystal Polymer 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    . Kiss G. and Porter R.S.J.Polvm.Sci.. Polvm.Svmp., 1978, 65, 193–211.CrossRefGoogle Scholar
  2. 2.
    Mewis J. and Moldenaers P. Mol.Crvst.Liq.Cryst., 1987,153, 291–300.Google Scholar
  3. 3.
    Gotsis A.D. and Baird D.G.J.Rheologv. 1985, 29, 539–556.CrossRefGoogle Scholar
  4. 4.
    Doi M.J.Polvm.Sci.. Polvm.Phvs., 1981, 19, 229.CrossRefGoogle Scholar
  5. 5.
    Marrucci G. and Maffettone P.L. Macromolecules. 1989.Google Scholar
  6. 6.
    Chapoy L.L., Marcher B. and Rasmussen K.H. Liq.Crvst., 1988, 3, 1611–1636.CrossRefGoogle Scholar
  7. 7.
    Wissbrun K.F., Kiss G. and Cogswell F.N. Chem.Eng.Comm., 1987, 53, 149–173.CrossRefGoogle Scholar
  8. 8.
    Onogi S. and Asada T. in Rheology. ed. G. Astarita, G. Marrucci and L. Nicolais, Plenum, New York, 1980, p.127.Google Scholar
  9. 9.
    Doi M. and Kuzuu N.J.Phvs.Soc.Japan. 1983, 52, 3486.CrossRefGoogle Scholar
  10. 10.
    Cocchini F., Aratari C. and Marrucci G., submitted to Macromolecules.Google Scholar

Copyright information

© Elsevier Science Publishers Ltd 1990

Authors and Affiliations

  • F. Cocchini
    • 1
  • M. R. Nobile
    • 2
  • D. Acierno
    • 2
  1. 1.EniChem R&SSan Donato MilaneseItaly
  2. 2.Istituto di Ingegneria Chimico-Alimentare, Facoltà di IngegneriaUniversità di SalernoSalernoItaly

Personalised recommendations