ABSTRACT Despite the increasing use of biodegradable polymers in additive manufacturing, their long‐term durability remains insufficiently understood. The aim of this study to investigate the influence of accelerated aging on the performance of fused filament fabrication‐printed polylactic acid/polyhydroxyalkanoate (PLA/PHA) specimens. The aging process was conducted up to 40 days, with comprehensive characterization performed, including colorimetric analysis, Fourier‐transform infrared spectroscopy (FTIR), differential scanning calorimetry, rheology, and mechanical testing. The results demonstrated a progressive increase in color difference (Δ E *) (from 2.23 to 3.09), attributed to an increase in b * value (from 20.05 to 22.70), indicating yellowing associated with thermo‐oxidative degradation and chromophoric group formation. FTIR analysis revealed that the primary chemical structure remained largely intact, although subtle intensity variations suggested early‐stage hydrolysis. Thermal analysis showed a gradual decrease in glass transition temperature ( T g ) and cold crystallization temperature ( T cc ), from 58.3°C to 57.1°C and from 116.8°C to 112.8°C, respectively. This result is in line with the increased crystallinity (from 14.4 to 18.0 J/g), which reflects enhanced chain mobility and structural rearrangement. Rheological results further indicated a competitive interplay between chain scission and secondary crystallization. In terms of mechanical performance, tensile and flexural properties improved at the initial stage (e.g., from 24.73 to 27.92 MPa for tensile strength and 29 to 31.3 MPa for flexural strength, respectively) due to increased crystallinity and molecular reorganization but declined as degradation mechanisms became dominant. Overall, this study provides valuable insights into predicting long‐term behavior and optimizing material design for sustainable 3D‐printed applications.
Xu et al. (Mon,) studied this question.