What is Chemical Resistance?

Simply stated, chemical resistance is the ability of a plastic to resist changes in its physical properties when exposed to certain chemicals. Depending upon the material and the application, this could be anything from soap solution to hot sulfuric acid. Specific properties, chemicals, and exposure conditions are stated in the various product standards.

How is Chemical Resistance Tested?

Several test specimens are produced, this may be injection molded bars, or even whole parts. In the case of destructive tests, where the specimen is damaged in the testing process, like tensile strength, the specimens are divided into test groups and a control group. The test groups are placed in vats of the required chemicals, while the control group is held in an environmental chamber under carefully controlled temperature and humidity conditions. After the exposure period, the groups are cleaned of any dangerous residue, and the tests performed.

In the case of nondestructive tests like physical dimensions, the test specimens are measured, then exposed to the required chemical conditions. After cleaning, the parts are again measured, and the amount of change noted.