Validation of real-time aging simulation of poly(lactic acid) (PLA) using accelerated aging in accordance with ASTM F1980

To advance the application of bio-based materials in medical technology, further research is required to assess their long-term performance. In common practice, accelerated aging tests based on ASTM F1980 are used in medical contexts to predict material behavior over time. This standard provides calculation guidelines to determine the equivalent storage duration under artificially accelerated aging conditions using a Q₁₀-factor. This factor, typically assumed to be 2, represents the increase in reaction rate due to elevated temperatures. In this study, a comparison was conducted between accelerated aged samples and their real-time equivalents using various PLA types. The results indicate that the standard assumption of Q₁₀ = 2 can lead to an overestimation of degradation, resulting in a misrepresentation of real-time aging behavior. This discrepancy is substantiated by experimental data, including mechanical, thermal, and chemical analyses. A key factor contributing to this deviation appears to be the reliance on overly simplistic assumptions regarding degradation kinetics, which fail to account for autocatalytic reactions and the inherently multi-stage nature of the degradation process. In the present study, this observation was further corroborated through the determination of material-specific Q₁₀-factors. These factors, found to range between 2.3 and 2.5, exhibited dynamic variations throughout the degradation process, highlighting the need for a refined approach to accelerated aging methodologies.