Advertisement

Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

Shear field modification of strongly flocculated suspensions — Aggregate morphology

Abstract

Rheological and microscopical studies have been made to elucidate the effects of shear fields on the morphology of concentrated, aggregated model colloids. The models employed are well-characterised, predominantly chargestabilised polymer latices, coagulated by the addition of excess electrolyte. Continuous shear rheological and viscoelastic measurements indicate a very significant decrease in shear yield stress, apparent viscosity and shear modulus following prolonged shearing.

Electron microscopy reveals the source of these changes. Freshly coagulated suspensions form networks that are porous, strong and qualitatively similar to simulated structures for diffusion limited aggregation. Following protracted shearing, the network structure is rearranged to yield discrete, tightly packed aggregates with a characteristic size, which is principally a function of the primary particle size.

This is a preview of subscription content, log in to check access.

References

  1. 1.

    Sherrington PJ, Oliver R (1981) In: Goldberg AS (ed), Granulation. Monograph in Powder Science and Technology. I Chem E

  2. 2.

    Jullien R, Meakin P (1989) J Colloid Interface Sci 127:265

  3. 3.

    Michaels AS, Bolger JC (1962) I and EC Fundamentals 1:153

  4. 4.

    van den Tempel M (1979) J Coll Interf Science 71:18

  5. 5.

    Strenge K, Sonntag H (1974) Colloid Polym Sci 252:133

  6. 6.

    Schoukens G, Mewis J (1978) J Rheol 22:381

  7. 7.

    Firth BA, Hunter RJ (1976) J Coll Interf Science 57:248–266

  8. 8.

    van de Ven TGM, Hunter RJ (1977) Rheol Acta 16:534

  9. 9.

    Hunter RJ, Frayne J (1979) J Coll Interf Science 71:30

  10. 10.

    van de Ven TGM, Hunter RJ (1979) J Coll Interf Science 68:135

  11. 11.

    Stewart RF, Sutton D (1986) Particulate Science and Technology 4:251

  12. 12.

    Donaldson CC, McMahon J, Stewart RF, Sutton D (1986) Colloids and Surfaces 18:373

  13. 13.

    Weitz DA, Oliveria M (1984) Phys Rev Lett 52:1433

  14. 14.

    Martin JE, Schaefer DW (1984) Phys Rev Lett 53:2457

  15. 15.

    Kolb M, Botet R, Julien R (1983) Phys Rev Letters 51:1123

  16. 16.

    Brown WD, Ball RC (1985) J Phys A: Math Gen 18:L517

  17. 17.

    Vicsek T, Family F (1984) Phys Rev Letters 52:1669

  18. 18.

    Meakin P (1984) J Coll Interf Science 102:491

  19. 19.

    Bagster DF, Tomi D (1974) Chem Eng Sci 29:1773

  20. 20.

    Adler PM, Mills PM (1979) J Rheol 23:25

  21. 21.

    Sonntag RC, Russel WB (1986,1987) J Coll Interf Sci 113:399; 115:378–390; 116:485

  22. 22.

    Buscall R, Mills PDA, Yates GE (1986) Colloids and Surfaces 18:341

  23. 23.

    Buscall R, McGowan IJ, Mills PDA, Stewart RF, Sutton D, White LR, Yates GE (1987) Journal of Non-Newtonian Fluid Mechanics 24:183

  24. 24.

    Buscall R, Mills PDA, Goodwin JW, Lawson DW (1988) J Chem Soc Faraday Trans I 84:4249

  25. 25.

    Goodwin JW, Hearn J, Ho CC, Ottewill RH (1974) Colloid Polym Sci 252:464

  26. 26.

    Goodwin JW, Ottewill RH, Pelton R, Vianello G, Yates DE (1978) Brit Polymer J 10:173

  27. 27.

    Bensley CN, Hunter RJ (1983) J Coll Interf Sci 92:436

  28. 28.

    Grover BW (1986) MSc Thesis, Univ of Bristol

  29. 29.

    Buscall R (1982) Colloids and Surfaces 5:269

  30. 30.

    Underwood EE (1970) Quantitative Stereology, Addison-Wesley

  31. 31.

    Partridge SJ (1985) PhD Thesis, Univ of Bristol

  32. 32.

    Yasa M (1977) Int J of Mineral Processing 4:293

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Mills, P.D.A., Goodwin, J.W. & Grover, B.W. Shear field modification of strongly flocculated suspensions — Aggregate morphology. Colloid Polym Sci 269, 949–963 (1991). https://doi.org/10.1007/BF00657312

Download citation

Key words

  • Polymerlatices
  • aggregatemorphology
  • shear
  • rheology
  • stronglyflocculatedsuspensions