There are many ways to evaluate the thermal oxidation stability of plastics. People like to use a variety of thermal analysis techniques, such as differential thermal analysis (DTA), differential scanning calorimetry (DSC), thermogravimetric analysis (TG) and thermomechanical analysis (TMA). These methods have a great advantage that can obtain data in a short period of time.
Relatively high temperature, but usually below the melting point of the polymer, accelerated aging in an oven (using circulating air or sometimes pure oxygen) is one of the most widely used test methods (such as DIN53383 Part 1, ISO77-1983). Test standards include spectral data, such as infrared spectrum base (DIN53383 Part 2) or base concentration data, colorimetric method to determine leg color and mechanical properties, such as impact strength, tensile strength and tensile strength. Some polymers, such as polycarbonate and polyamines, can easily detect the changes in the molecular scale caused by the aging of the solution (DIN 53727, ISO 307-1977, ASTM D2857-1987). In practice, the thermogravimetric analysis method is limited when it is used to determine the weight loss of polyacetal.
The research on the specific surface area of antioxidants is very important. The specific surface area detection data of antioxidants is true and reliable only if the results are detected by the BET method. There are many domestic instruments that can only be tested by direct comparison method. eliminated. At present, the domestic and foreign specific surface area tests uniformly adopt the multi-point BET method. The specific surface area measurement standards developed at home and abroad are all based on the BET test method. Please refer to my country's National Standard (GB/T 19587-2004)-Gas Adsorption BET Principle A method for determining the specific surface area of solid materials. Specific surface area detection is actually a relatively time-consuming task. Due to the different adsorption capacity of the sample, the test of some samples may take a whole day. If the test process is not fully automated, the tester cannot leave at all times and must A high degree of concentration, observing the dashboard and controlling the knobs, a little carelessness will lead to the failure of the test process, which will waste a lot of valuable time of the tester. The F-Sorb 2400 specific surface area tester is an instrument that can truly realize the detection function of the BET method (both direct comparison method). More importantly, the F-Sorb 2400 specific surface area tester is the only fully automated and intelligent specific surface area testing equipment in China so far. , The test results are highly consistent with international standards, and the stability is also very good. At the same time, it reduces human error and improves the accuracy of test results.
