Abstract
The goal of this investigation is to understand a distinctive feature observed in differential scanning calorimetry (DSC) measurements of steam sterilized medical polymer products, the formation of a peak upon the first DSC heating, known as the “memory effect”. The observed phenomenon could be used to provide evidence for steam sterilization. For the investigations, polypropylene (PP) and polyethylene (PE) samples were steam sterilized or thermally treated in an oven applying different conditions. Afterwards, the samples were measured by DSC. The influences of thermal treatment and mechanical stress were analyzed. In addition, various polyolefin reference materials (PE and PP) were investigated to address the influence of composition. Furthermore, the durability of the signal with respect to time and temperature effects were examined. The investigation shows that it is possible to produce a stable memory effect.
Kurzfassung
DSC-Messungen von dampfsterilisierten medizinischen Produkten aus Polyolefinen zeigen beim ersten Heizvorgang als auffällige Besonderheit eine zusätzliche Stufe, bekannt als Temperpeak. Das Ziel dieser Untersuchungen ist, dieses Phänomen nachzuvollziehen und zu verstehen, um es als Nachweis für die Dampfsterilisation nutzen zu können. Dafür wurden PP- und PE-Proben unter verschiedenen Bedingungen dampfsterilisiert und im Ofen thermisch behandelt. Anschließend wurden die Proben mittels DSC untersucht und die Einflüsse der thermischen Behandlung und der mechanischen Beanspruchung analysiert. Um den Einfluss unterschiedlicher Materialspezifikationen zu prüfen, wurden zusätzlich verschiedene Referenzmaterialien (PE und PP) untersucht und GPC-Messungen durchgeführt. Des Weiteren wurde die Beständigkeit des Signals gegenüber der Zeit und der Temperatureinflüssen betrachtet. Die Untersuchungen zeigen, dass sich ein stabiler Memory-Effekt erzeugen lässt.
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