Environmental stress cracking

Crazes (surface cracks) produced by ESC in PMMA drinking beaker

Environmental Stress Cracking (ESC) is one of the most common causes of unexpected brittle failure of thermoplastic (especially amorphous) polymers known at present. According to ASTM D883, stress cracking is defined as "an external or internal crack in a plastic caused by tensile stresses less than its short-term mechanical strength". This type of cracking typically involves brittle cracking, with little or no ductile drawing of the material from its adjacent failure surfaces.[1] Environmental stress cracking may account for around 15-30% of all plastic component failures in service.[2] This behavior is especially prevalent in glassy, amorphous thermoplastics.[3] Amorphous polymers exhibit ESC because of their loose structure which makes it easier for the fluid to permeate into the polymer. Amorphous polymers are more prone to ESC at temperature higher than their glass transition temperature (Tg) due to the increased free volume. When Tg is approached, more fluid can permeate into the polymer chains.[4]

  1. ^ Cite error: The named reference :3 was invoked but never defined (see the help page).
  2. ^ H. F. Mark (2004). Encyclopedia of Polymers Science and Technology – 3rd Ed. Vol 12. John Miley & Sons Inc.
  3. ^ Henry, L. F. (1974). "Prediction and evaluation of the susceptibilities of glassy thermoplastics to environmental stress cracking". Polymer Engineering & Science. 14 (3): 167–176. doi:10.1002/pen.760140304. ISSN 1548-2634.
  4. ^ J. Scheirs (2000). Compositional and Failure Analysis of Polymers. J. Wiley & Sons.

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