Effect of Molecular Structure on the Short-Term and Long-Term Mechanical Behavior of High-Density Polyethylene
Publication: Journal of Materials in Civil Engineering
Volume 26, Issue 5
Abstract
Environmental stress cracking (ESC) of polyethylene (PE) in structural applications can result in catastrophic failure without any visible warning. Polyethylene with excellent short-term mechanical strength can have poor long-term performance because of ESC. Because PE structures can have an expected service life of 50 years or more, the lack of understanding regarding their long-term mechanical performance is a major concern. For practical reasons, it is not possible to test PE for years before use. Currently, most mechanical tests for PE only run for a few hours. Therefore, it is important to understand the connections between short-term and long-term mechanical properties. Short-term mechanical behavior, such as creep over 8 h, is studied in conjunction with ESC for six high-density PE resins. In addition, the molecular structure influences on creep of PE are extensively investigated. Complex creep behavior is explained from the point of combined effects of molecular properties. It was found that high-density polyethylene (HDPE) resins with large creep strain usually exhibit high environmental stress cracking resistance. However, the short-term creep behavior of HDPE was affected by molecular weight, molecular weight distribution, and short-chain branching content of the material.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The authors would like to thank the Natural Sciences and Engineering Research Council (NSERC) of Canada, the Canada Research Chair (CRC) program of NSERC, and ExxonMobil Chemical Canada (Imperial Oil Canada) for financial support. The authors would also like to thank ExxonMobil Chemical Canada (Imperial Oil Canada), Nova Chemicals Ltd. (Canada), and Repsol YPF (Spain) for supplying resins.
References
Alvarado-Contreras, J. A. (2007). “Micromechanical modelling of polyethylene.” Ph.D. thesis, Dept. of Civil Engineering, Univ. of Waterloo, Waterloo, ON, Canada.
ASTM. (2003). “Standard Test Method for Tensile Properties of Plastics.”.
ASTM. (2012). “Standard test method for evaluation of stress crack resistance of polyolefin geomembranes using notched constant tensile load test.”.
Behjat, Y. (2009). “Relationship between short-term and long-term creep, and the molecular structure of polyethylene.” M.A. Sc. thesis, Univ. of Waterloo, Waterloo, ON, Canada.
Cheng, J. J. (2008). “Mechanical and chemical properties of high density polyethylene: Effects of microstructure on creep characteristics.” Ph.D. thesis, Dept. of Chemical Engineering, Univ. of Waterloo, Waterloo, ON, Canada.
Cheng, J. J., Alvarado-Contreras, J. A., Polak, M. A., and Penlidis, A. (2010). “Chain entanglements and mechanical behaviour of high density polyethylene: Independent modeling corroboration of experimental observations.” J. Eng. Mater. Technol., 132(1), 011016.
Cheng, J. J., Polak, M. A., and Penlidis, A. (2008). “A tensile strain hardening test indicator of environmental stress cracking resistance.” J. Macromol. Sci., Part A: Pure Appl. Chem., 45(8), 599–611.
Cheng, J. J., Polak, M. A., and Penlidis, A. (2009a). “Phase interconnectivity and environmental stress cracking resistance of polyethylene: A crystalline phase investigation.” J. Macromol. Sci., Part A: Pure Appl. Chem., 46(6), 572–583.
Cheng, J. J., Polak, M. A., and Penlidis, A. (2009b). “Polymer network mobility and environmental stress cracking resistance of high density polyethylene.” Polym.—Plast. Technol. Eng., 48(12), 1252–1261.
Gokhale, S., Hamm, R., and Sterling, R. (1999). “A comprehensive survey on the state of horizontal directional drilling in North America provides an inside look at this increasingly growing industry.” Directional Drilling, 7(1), 20–23.
Huang, Y., and Brown, N. (1988). “The effect of molecular weight on slow crack growth in linear polyethylene homopolymers.” J. Mater. Sci., 23(10), 3648–3655.
Liu, H., Polak, M. A., and Penlidis, A. (2008). “A practical approach to modeling time-dependent nonlinear creep behaviour of polyethylene for structural applications.” Polym. Eng. Sci., 48(1), 159–167.
Lustiger, A., and Markham, R. L. (1983). “Importance of tie molecules in preventing polyethylene fracture under long-term loading conditions.” Polymer, 24(12), 1647–1654.
Nitta, K. H., and Ishiburo, T. (2004). “Failure envelope curves in polyethylene solids.” Macromol. Symp., 214, 251–259.
O’Connell, P. A., Duckett, R. A., and Ward, I. M. (2002). “Brittle-ductile transitions in polyethylene.” Polym. Eng. Sci., 42(7), 1493–1508.
Polak, M. A., Duyvestyn, G. M., and Knight, M. A. (2004). “Experimental strain analysis for polyethylene pipes installed by horizontal directional drilling.” Tunnelling Underground Space Technol., 19(2), 205–216.
Rasburn, J., Klein, P. G., and Ward, I. M. (1994). “The influence of short-chain branching on the creep-behavior of oriented polyethylene, and its effect on the efficiency of cross-linking by electron-irradiation.” J. Polym. Sci. Part B: Polym. Phys., 32(8), 1329–1338.
Zhang, C. T., and Moore, I. D. (1997). “Nonlinear mechanical response of high density polyethylene. Part I: Experimental investigation and model evaluation.” Polym. Eng. Sci., 37(2), 404–413.
Information & Authors
Information
Published In
Journal of Materials in Civil Engineering
Volume 26 • Issue 5 • May 2014
Pages: 795 - 802
Copyright
© 2013 American Society of Civil Engineers.
History
Received: May 27, 2011
Accepted: Feb 15, 2013
Published online: Feb 18, 2013
Discussion open until: Jul 18, 2013
Published in print: May 1, 2014
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.