SKZ offers accelerated material testing using high-pressure autoclave testing
The Plastics Center SKZ is one of the few testing laboratories in the world that is able to accelerate the thermo-oxidative ageing of plastics using the high-pressure autoclave test. This method makes it possible to compare plastics equipped with different stabilizer packages quickly and effectively.
Autoclave testing in the laboratories of the SKZ testing department (Photo: Luca Hoffmannbeck, SKZ)
Up to ten times faster thermo-oxidative ageing possible
Compared to conventional oven ageing, the high-pressure autoclave test offers up to ten times faster thermo-oxidative ageing due to increased oxygen availability at moderate temperatures. This makes it possible to evaluate material stability within a few weeks or months. The test specimens are immersed in an aqueous medium, which allows leaching and hydrolysis effects to be taken into account. In addition, the influence of the pH value on ageing can be investigated. This ensures a comprehensive analysis.
Precise monitoring
The oxygen pressure in the high-pressure autoclave is recorded continuously. This data makes it possible to track the oxygen consumption of the material under investigation during oxidation. For example, it has been shown with polyethylene (HDPE) samples that an increased oxygen demand is associated with a decrease in mechanical properties. A change in oxygen consumption can therefore serve as an indicator for the onset of thermo-oxidative failure of the material. The thermo-oxidative lifetime can be estimated by testing at five different combinations of temperature and oxygen pressure with subsequent Arrhenius-type evaluation. For a quick formulation comparison, a one-point test can also be performed, which does not provide a lifetime estimate, but allows a quick assessment of the performance of the formulation and antioxidants.
Only a few testing institutes offer high-pressure autoclave tests
“Using the high-pressure autoclave gives us the opportunity to test plastic products more quickly so that we can offer more efficient solutions,” explains Anja Armani, Project Manager at SKZ.” “There are only a few testing institutes in the world that carry out such tests,” adds Alexander Ebenbeck, Head of Sales Testing.
More about the ageing tests
