The memory effect in polyolefinic products: A tool for confirming the steam sterilization process

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.