Investigation of the physical aging effect on polylactic acid/polymethyl methacrylate biomaterial blends

Abstract Polylactic acid (PLA) suffers from inherent brittleness and poor thermal stability, which limit its broader application. Blending PLA with poly (methyl methacrylate) (PMMA) represents a promising strategy to improve these properties; however, the long-term performance of such blends is strongly influenced by physical aging phenomena, which remain insufficiently understood. In this study, PLA/PMMA blends containing 0–30 wt% PMMA were prepared via solution casting. Blend miscibility was confirmed by Fourier transform infrared spectroscopy, Raman spectroscopy, and differential scanning calorimetry. Thermogravimetric analysis showed that the incorporation of PMMA enhances the thermal stability of PLA. Physical aging behavior was investigated by differential scanning calorimetry through controlled cooling and sub-T g annealing. The results demonstrate that processing history and aging conditions significantly affect the structural relaxation and thermodynamic stability of PLA/PMMA blends, highlighting the key role of physical aging in determining their long-term performance.