The ESC can be defined as the acceleration of stress cracking due to contact with a fluid (liquid or steam, for example, caustic solutions on polypropylene) or with “bulking” agents without chemical degradation.
The mechanism is purely physical. The interactions between the fluid, the stress and the polymer include: a local yield strength with localized absorption of the fluid, a plasticization of the area with formation of cracks, the growth of the cracks and the corresponding fracture of the material without irreversible chemical changes.
The device is compliant with ASTM D 1693.
The ESCR (Environmental Stress Cracking Resistance) expresses the number of hours after which 50% of the specimens subjected to the test generate cracks.
The test requires to notch a number of specimens, bending at 180 ° and place them in a reagent kept at a constant temperature.