Oxidation induction time is used to test the anti-oxidation ability of HDPE geomembrane. The test is through accelerated test to simulate the duration of geomembrane in oxidative environment.
During the construction and use of HDPE geomembrane, it is exposed to oxygen environment for a long time. Oxygen can make everything age, and geomembrane is no exception.
By testing the oxidation induction time, the content level of antioxidants in the geomembrane can be known, so that the long-term performance of the geomembrane can be judged. Oxidation induction time is a very important technical index to consider the long-term performance of HDPE geomembrane.
The principle of the experiment:
Add stabilizers, such as antioxidants, to polymer materials to prevent the spread of oxidation reactions; however, antioxidants will be consumed in high-temperature oxygen environments. When they are completely consumed, the oxidation reaction will be rapid and a large amount of heat will be released. DSC is sensitive to this heat. The change is very sensitive, and the time required for the sample to undergo oxidative degradation is measured by DSC, which is called the thermal oxygen stability of the oxidation induction period (oxidation induction time, OIT for short).
Significance of the experiment:
Sufficient OIT can ensure that the product does not degrade during processing, storage, transportation and other links;
Sufficient OIT can ensure that the product does not degrade during the welding process, especially film products;
Sufficient OIT can ensure that the product has a sufficient service life during use.
Note: OIT is an important parameter to ensure geomembrane products;
Should not be excessive pursuit of high OIT index.
Notes for OITs:
Aluminum dishes are used instead of copper dishes and porcelain crucibles. The experimental results of different utensils vary widely;
Some also need to do a set of high-pressure oxidation induction time, which is to avoid misleading the evaluation of the anti-oxidation system by ordinary OIT experiments.