Journal of Materials Science

, Volume 23, Issue 10, pp 3648–3655 | Cite as

The effect of molecular weight on slow crack growth in linear polyethylene homopolymers

  • Yan -Ling Huang
  • Norman Brown


The rate of initiation and growth of cracks in linear high-density polyethylene with different molecular weights was observed in single-edge-notched tensile specimens under plane strain condition as a function of applied stress, notch depth and temperature. The initial rates of crack initiation all have the form of m a 0 n exp (−Q/RT) or AKpexp (−Q/RT) where σ = stress, a0 = notch depth and K= stress intensity factor. For the different molecular weights, m, n, P and Q are almost the same where m=5, n=2, P=4.7 and Q=115 kJ mol−1, but the constants C and A varied as (¯Mw−¯Mc)−1 where ¯Mc is a limiting molecular weight for sudden fracture. A molecular model based on tie-molecules has been used to explain the dependence on ¯Mw. The effect of ¯Mw on the fast-fracture strength at low temperature and the relationship to tie-molecules have also been investigated. Quantitative relationships between the concentration of tie-molecules and the fracture behaviour have been obtained.


Molecular Weight Stress Intensity Intensity Factor Stress Intensity Factor Crack Initiation 
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.
    X. Lu and N. Brown, J. Mater. Sci. 21 (1986) 2423.Google Scholar
  2. 2.
    Idem, ibid. 21 (1986) 4081.Google Scholar
  3. 3.
    S. K. Bhattacharya and N. Brown, ibid. 19 (1984) 2519.Google Scholar
  4. 4.
    J. G. William, “Fracture Mechanics of Polymers” (Wiley, New York, 1986) p. 64.Google Scholar
  5. 5.
    M. K. V. Chan and J. G. William, Polymer 24 (1983) 234.Google Scholar
  6. 6.
    E. Kamei and N. Brown, J. Polym. Sci., Polym. Phys. Edn 22 (1984) 543.Google Scholar
  7. 7.
    X. Lu and N. Brown, Polymer 28 (1987) 1505.Google Scholar
  8. 8.
    A. G. Gibson, S. A. Jaward, G. R. Davies and I. M. Ward, ibid. 23 (1982) 349.Google Scholar
  9. 9.
    H. D. Keith, F. J. Padden Jr and R. G. Vadimsky, J. Polym. Sci., Part A-2 4 (1966) 267.Google Scholar
  10. 10.
    E. J. Kramer, in “Advances in Polymer Science”, Vol. 52/53, edited by H. H. Kausch (Springer, New York, 1983) p. 33.Google Scholar
  11. 11.
    G. Cappaccio and I. M. Ward, J. Mater. Sci. 15 (1980) 2897.Google Scholar
  12. 12.
    L. Mandelkern, “Introduction to Macromolecules”, 2nd Edn (Springer Verlag, New York, 1982) p. 39.Google Scholar
  13. 13.
    P. Prentice, J. Mater. Sci. 20 (1985) 1445.Google Scholar
  14. 14.
    N. Brown and I. M. Ward, ibid. 18 (1983) 1405.Google Scholar
  15. 15.
    J. Smook, W. Hamersma and A. J. Pennings, ibid. 19 (1984) 1359.Google Scholar
  16. 16.
    A. Kelly, “Strong Solids”, 2nd Edn (Clarendon, Oxford, 1973) p. 10.Google Scholar

Copyright information

© Chapman and Hall Ltd 1988

Authors and Affiliations

  • Yan -Ling Huang
    • 1
  • Norman Brown
    • 1
  1. 1.Department of Materials Science and EngineeringUniversity of PennsylvaniaPhiladelphiaUSA

Personalised recommendations