Non-Isothermal Degradation Mechanism of Micro/Nano Titanium Dioxide-Enhanced Polycaprolactone Biocomposite

Abstract

Understanding the degradation behavior of polymer composites is crucial for their practical application, especially in areas such as biomedicine and environmental engineering. In this study, we investigated the influence of titanium dioxide (TiO2) particle size and content, containing 0.5, 1, 2, 5, and 10 wt% m/nTiO2, on the degradation mechanism of biodegradable polycaprolactone (PCL) biocomposites. The degradation kinetics of the prepared biocomposites were evaluated using the Friedman method in conjunction with multivariate nonlinear regression facilitated by the Netzsch Thermokinetics software. The results indicate different degradation mechanisms for PCL biocomposites containing TiO2 microparticles compared to biocomposites containing TiO2 nanoparticles. However, the PCL biocomposites with TiO2 microparticles showed a three-step degradation process, and the PCL biocomposites with TiO2 nanoparticles exhibited a four-step degradation process. This difference can be attributed to the observed agglomeration of TiO2 nanoparticles within the PCL matrix, which leads to an additional diffusion step in the degradation process. Interestingly, the addition of TiO2 particles did not change the basic degradation mechanism of PCL but prolonged the degradation process to a higher conversion range. These findings shed light on the complicated interplay between the properties of the filler particles and the behavior of the polymer matrix and provide valuable clues for the design and optimization of biodegradable biocomposites.