Advertisement

Journal of Materials Science

, Volume 20, Issue 5, pp 1625–1630 | Cite as

The supercooling dependence of the initial fold length of polyethylene crystallized from the melt: unification of melt and solution crystallization

  • P. J. Barham
  • R. A. Chivers
  • A. Keller
  • J. Martinez-Salazar
  • S. J. Organ
Papers

Abstract

Following the previous recognition [1], reached with the aid of real time low angle X-ray diffraction (using a synchrotron X-ray source) that in melt crystallized polyethylene the initial (primary) lamellar thickness is much smaller than hitherto envisaged, we have proceeded to construct the full relationship between primary fold length (Ig*) and supercooling (ΔT) covering a wide range of crystallization temperature (Tc). The principal result of this work is the identification of supercooling as the sole factor which determinesIg*. Comparison with crystallization from solution [2–4] has revealed that theIg* against ΔT curves are completely superposable thus removing the gap which has existed up to the present between melt and solution crystallization, bringing about a welcome unification of these two separate (at least as far as fold length was concerned) aspects of polymer crystallization. Further, we show that while ΔT determinesIg*, subsequent thickening is determined by the absolute temperature. Isothermal thickening in particular proceeds first by a large discontinuous step followed by a continuous logarithmic increase with time. The importance of these findings and in particular the affirmation of the unique role of supercooling for chain folding and lamellar crystallization in general is emphasized.

Keywords

Crystallization Crystallization Temperature Unique Role Principal Result Lamellar Thickness 
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.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    J. Martinez-Salazar, P. J. Barham, andA. Keller,J. Mater. Sci. 20 (1985) 1616.Google Scholar
  2. 2.
    S. J. Organ andA. Keller,ibid. 20 (1985) 1571.Google Scholar
  3. 3.
    Idem, ibid. 20 (1985) 1586.Google Scholar
  4. 4.
    Idem, ibid. 20 (1985) 1602.Google Scholar
  5. 5.
    J. J. Weeks,J. Natl. Bur. Stand. US 67A (1963) 441.Google Scholar
  6. 6.
    J. Dlugosz, G. V. Fraser, D. Grubb, A. Keller andP. L. Goggin,Polymer 17 (1976) 471.Google Scholar
  7. 7.
    P. J. Barham, R. A. Chivers, D. A. Jarvis, A. Martinez-Salazar andA. Keller,J. Polym. Sci. Polym. Lett. Ed. 19 (1981) 539.Google Scholar
  8. 8.
    R. A. Chivers, P. J. Barham, J. Martinez-Salazar andA. Keller,ibid. 20 (1982) 1717.Google Scholar
  9. 9.
    P. J. Barham, D. A. Jarvis andA. Keller,ibid. 20 (1982) 1743.Google Scholar
  10. 10.
    J. D. Hoffman, G. T. Davies andJ. I. Lauritzen, in “Treatise on Solid State Chemistry”, Vol. 3, edited by Hannay (Plenum Press, New York, 1976).Google Scholar
  11. 11.
    J. D. Hoffman, L. J. Frolen, G. S. Ross andJ. I. Lauritzen,J. Res. Natl. Bur. Stand. US 79A (1975) 671.Google Scholar
  12. 12.
    J. Martinez-Salazar, P. J. Barham andA. Keller,J. Polym. Sci. Polym. Phys. Ed. 22 (1984) 1085.Google Scholar
  13. 13.
    J. Rault,J. Macromol. Sci. B15 (1978) 567.Google Scholar
  14. 14.
    D. M. Sadler,Polymer 24 (1983) 1401.Google Scholar
  15. 15.
    W. K. Burton, N. Cabrera andF. C. Frank,Philos. Trans. R. Soc. London 243A (1951) 299.Google Scholar
  16. 16.
    K. A. Jackson, in “Crystal Growth” (Pergamon, Oxford, 1967).Google Scholar
  17. 17.
    D. M. Sadler andG. H. Gilmer,Polymer, in press.Google Scholar

Copyright information

© Chapman and Hall Ltd 1985

Authors and Affiliations

  • P. J. Barham
    • 1
  • R. A. Chivers
    • 1
  • A. Keller
    • 1
  • J. Martinez-Salazar
    • 1
  • S. J. Organ
    • 1
  1. 1.HH Wills Physics LaboratoryUniversity of BristolBristolUK

Personalised recommendations