Degradation studies of a commercial radiation‐resistant polypropylene sterilized by gamma and electron beam technology before and after subsequent accelerated aging cycles

Abstract

Irradiation is one of the most widely used technologies for sterilization of medical products. Unfortunately, some polymers in the medical field are susceptible to high-energy radiation. In the case of polypropylene, this leads to yellowing and embrittlement due to degradation mechanisms. This study compares the impact of gamma and eBeam sterilizations at a dose of 45 kGy on a commercially available, radiation-resistant polypropylene in combination with accelerated aging studies. Mechanical behavior as well as yellowing, accompanied by structural investigations like molar mass characterization and crystallinity analysis, have been investigated. It is shown that eBeam has less damaging effects compared with gamma irradiation. This is shown by an initial drop in elongation at break by 46% for gamma irradiated samples in contrast to 24% decrease using eBeam irradiation. Also, an initial drop in molar mass by 43% was found for gamma irradiated samples and by 27% for eBeam. Change in color was observed by an initial increase in the yellowness index of 42% at samples after gamma irradiation, respectively, of 22% for eBeam irradiated samples. Interestingly, molar mass remained constant during aging, whereas yellowing and Embrittlement further change. Additionally, empirical equations were found, which describe the experimental data.

Stability assessment of a commercial polypropylene copolymer and Irgafos 168 under repeated injection molding and γ‐irradiation cycles

“…According to Ehrenstein, 36 the elongation at break is a reliable indicator of toughness. Kremser et al likewise chose elongation at break as altering indice due to its high sensitivity to material degradation 37 . Figure 6 shows the mean of five measurements of the elongation at break of the specimens in percentage as a function of the processing cycles, the injection‐molded specimens as filled bars, the additionally irradiated specimens as hatched bars.…”

Study on hypoglycemic effects of irradiated ginseng adventitious roots

“…However, Caire-maurisier et al put forward that the irradiation of polyethylene terephthalate with 25 kGy electron beam produced polymers, including benzoic acid, terephthalic acid, etc ( Caire-Maurisier et al, 2019 ). Kremser et al discovered that 45 kGy γ-rays irradiation decreased the elongation at the break of polypropylene by 46% ( Kremser et al, 2020 ). Therefore, the use of irradiation technology for food processing should also be concerned about the risk to food safety caused by its impacts on packaging materials.…”

Determination of oleamide bulk‐to‐surface distribution in polypropylene for medical use depending on sterilization method and storage time

“…When sterilizing polymers with radiation changes in the molecular structure can occur. In the presence of oxygen this can lead to oxidation, [ 17 ] resulting in decomposition of the main chain, bond scission and/or cross‐linking. [ 15,16,18,19 ] Autoclaving, which was also investigated as an example for a heat treatment, can result in thermal degradation of polymers, resulting in oxidation and hydrolysis.…”

“…[ 16 ] Therefore, it is not a large‐scale industrial procedure for polymers but widely used in medical practices and a possible way to perform sterilization of medical devices in crisis areas without sufficient supply of disposable products. Although it is well known that different sterilization methods have different influences on polymers like reducing their mechanical properties, yellowing, chain scission and/or crosslinking and degradation, [ 17,20,21 ] no literature could be found on the comparison of the specific influence of these sterilization methods on the migrating properties of the lubricant oleamide in polypropylene.…”