Stress cracking

Stress cracking is a critical mechanism that often causes the premature failure of plastic parts. This occurs when surface-active substances act on the material. Particularly in the case of polyethylene (PE) and polypropylene (PP), even a short exposure to aqueous wetting agents, or in the case of PMMA (polymethyl methacrylate) to fatty acids, can lead to stress cracks.

The susceptibility to stress cracking varies depending on the type of plastic. Styrene polymers and other thermoplastics can also be affected, whereby alcohols can act as promoting factors, although less effectively compared with other substances.