Explanation

The ability of materials to remain uncracked under certain environmental factors (such as temperature, humidity, atmosphere, liquid medium) and stress can be measured through stress cracking experiments. stress cracking refers to the formation of visible cracks inside and outside the materials under the action of a stress lower than the mechanical strength of the materials. For example, according to the requirements of GB/T1842-2008, artificial nicking and bending test can be conducted on the surface of polyethylene samples, and then these samples can be immersed in different liquid media at different temperatures. During this process, no less than ten specimens can be tested in parallel and the time required for the crack rate of the specimens to reach 50% can be recorded. The longer this time is, the stronger the environmental stress cracking resistance resistance of materials is, that is, it has better stress cracking resistance.

Classification