Of ketchup and lupins
SKZ offers a wide range of accelerated aging tests for plastics. These tests are essential to ensure the durability and quality of materials in various applications. Test methods range from chemical resistance tests, accelerated ageing by temperature and artificial weathering by radiation, to biological resistance tests using plants and micro-organisms.
SKZ has a broad test portfolio in its laboratories. (Photo: Luca Hoffmannbeck, SKZ)
SKZ offers extensive testing capabilities to simulate accelerated material aging
A chemical resistance test, which can be performed at elevated temperatures, involves exposing material samples to various chemicals. The chemicals used depend on the application of the product. They range from desalinated water, milk of lime, acids and organic alcohols to artificial slurry, liquid manure or silage leachate. SKZ also conducts tests on aviation fuel and heating oil. Another specialty is testing the resistance of plastics in food products such as orange juice or tomato ketchup.
Accelerated Corrosion
Salt spray testing typically involves subjecting coated material or component specimens to accelerated corrosion attack by applying a corrosion-promoting atmosphere in a specially designed test chamber. Sodium chloride (NaCl) or NaCl mixtures are typically used as the spray media. The duration of the test depends on the requirements of the materials or components in service and can range from a few hours to several weeks. During the test, pH, salt concentration and temperature are monitored and kept constant to ensure reproducible results. At the end of the test, the specimens are usually visually or microscopically inspected for signs of corrosion or surface defects.
Assessing the tendency to crack
Another test method is the Stress Cracking Test (ESCT), such as the Bending Strip Test or the aFNCT (accelerated Full Notch Creep Test). Both tests evaluate the tendency of materials to crack when subjected to mechanical stress and a stress-cracking medium.
Simulation of Extreme Conditions
Resistance tests at elevated temperatures and possibly elevated oxygen availability are particularly relevant for thermo-oxidative life assessment. The SKZ offers the possibility to perform classical heat aging / oven aging up to 220 °C. For particularly durable materials, the high-pressure autoclave test method (up to 100 °C and 50 bar oxygen overpressure) is recommended: Extreme conditions are simulated by exposing samples to high temperatures and increased oxygen availability. The SKZ test portfolio also includes cold storage down to -60 °C and climate change tests according to automotive regulations, such as PV 1200, which simulates the interaction between different environmental conditions such as temperature, humidity and load. Internal pressure creep testing is critical to confirming the durability of pipes and containers. If plastics are exposed to light in the application, the SKZ offers tests for outdoor weathering simulation, weathering behind window glass, lightfastness tests and UV-C weathering.
Rooting tests with different plants
In addition to the influences mentioned above, biological components such as microorganisms or roots can also damage plastic products in contact with the soil. For this reason, the SKZ test program includes a microbiological resistance test and rooting tests with various plants. The FLL test (Forschungsgesellschaft Landschaftsentwicklung Landschaftsbau e.V.) lasts two years in the greenhouse and is carried out with couch grass and firethorn as test plants. A test with firethorn as a test plant is described in the EN 13948 standard. In the lupin test, it can be seen after about eight weeks whether the sample has been able to withstand the roots of the lupins.
"Guaranteeing the long-term durability of plastics
"Aging tests are crucial for testing and ultimately ensuring the long-term durability of plastics," says Alexander Ebenbeck, head of sales testing at SKZ. "This is the only way manufacturers can ultimately produce high-quality products that can withstand real-life operating conditions."
Learn more about aging tests at SKZ
