R&D Department

Environmental Stress Cracking Resistance (ESCR)

Environmental Stress Cracking is the main cause of breakage of plastic components. ESC can be defined as the acceleration of stress cracking due to contact with a fluid (liquid or vapor, e.g. caustic solutions on polypropylene) or “bulking” substances without chemical degradation.

The mechanism is purely physical. Interactions between fluid, stress and polymer include: local yield strength with localized absorption of the fluid, plasticization of the area with crack formation, growth of cracks and corresponding fracture of the material without irreversible chemical changes.

ESCR (Environmental Stress Cracking Resistance) refers to the number of hours in which 50% of the tested samples develop cracks.

The test requires notching a series of samples, bending them at 180°, and placing them in a reagent kept at a constant temperature.