Abstract
Brittle fractures in polypropylene and nylon were obtained in the temperature range −180 to −10° C and −160 to 20° C, respectively. The fracture toughness results of surface notches and single edge notches showed a remarkable thickness dependence. This effect was explained in terms of a plane strain (K C1) and a plane stress (K C2) toughness value using a bi-modal fracture analysis. While K C1 in both materials was generally insensitive to temperature, K C1 was temperature dependent showing substantial viscoelastic effects. In polypropylene, the linear relationship between K C2 and temperature (7”) was associated with the β and γ processes over the same temperature range. In nylon, there was a one-to-one correspondence between the K C2 changes and the tan δ peaks due to the β and γ relaxation processes. Using a modified crack tip opening displacement (u) equation, i.e. u = ((KC2 − K C1 )/σ y )2ey, where σ y and ey are the yield stress and yield strain respectively, a constant u criterion was found to describe the fracture behaviour of both materials in the temperature ranges of the β and γ processes.
Similar content being viewed by others
References
G. P. Marshall, L. H. Coutts and J. G. Williams, J. Mater. Sci. 9 (1974) 1409.
M. Parvin and J. G. Williams, ibid 10 (1975) 1883.
Idem, ibid 11 (1976) 2045.
A. G. Atkins, C. S. Lee and R. M. Caddell, ibid 10 (1975) 1381.
Y. W. Mai and A. G. Atkins, ibid 11 (1976) 677.
W. F. Brown, Jr and J. Srawley, ASTM STP 410 (1966).
G. R. Irwin, J. Appl. Mechs. December 29 (1962) 651.
H. W. Starkweather in “Nylon Plastics”, edited by M. I. Kohan (John Wiley and Sons, New York, 1973) p. 307.
P. I. Vincent, Polymer 15 (1974) 111.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Mai, Y.W., Williams, J.G. The effect of temperature on the fracture of two partially crystalline polymers; polypropylene and nylon. J Mater Sci 12, 1376–1382 (1977). https://doi.org/10.1007/BF00540851
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00540851