Differential scanning calorimeter for measuring the oxidation induction period time of PPR pipes

PPR pipes are widely used in building water supply and drainage systems due to their excellent corrosion resistance and thermal fusion performance. However, long-term exposure to ultraviolet radiation and high temperature and humidity environments can easily lead to oxidative degradation, resulting in material brittleness and even water leakage accidents. The oxidation induction period (OIT), as a core indicator for measuring the antioxidant capacity of polymers, can quickly evaluate the heat and oxygen aging resistance of materials.

1、 Operation steps of the experiment

1. Measuring instrument: DZ-DSC300 differential scanning calorimeter

2. Measurement sample:

Cut the PPR pipe sample into thin slices of approximately 10mg, ensuring that the surface of the sample is smooth and free of impurities.

3. Experimental parameter settings:

Perform temperature calibration before the experiment. The temperature calibration uses standard substances such as indium and tin, and the baseline calibration is carried out under a nitrogen atmosphere, with a heating rate of 10 ℃/min from room temperature to 200 ℃ to ensure stable instrument performance.

4. Test chart:

5. Data analysis:

The oxidation induction time (OIT) was detected by DSC (differential scanning calorimetry). The sample is usually heated to a specified temperature and kept at a constant temperature under a nitrogen atmosphere, and then switched to an oxygen atmosphere. After a period of time, the material begins to oxidize and release heat. This released heat is detected by a sensor and analyzed by software to obtain the Induced Oxidation Time (OIT). The length of the oxidation induction time is a meaningful parameter for the material's ability to resist oxidative decomposition. From the above figure, it can be concluded that the OIT of the material at 200 ℃ is 44.3 minutes.

6. Conclusion of the experiment:

In practical applications, if PPR pipes are exposed to high temperatures for a long time, their oxidation induction period will gradually shorten, thereby affecting the service life of the pipes. Therefore, when selecting and using PPR pipes, attention should be paid to their oxidation induction period indicators to ensure that they meet the requirements of the usage conditions.