Enhancing the photostability and mechanical properties of poly‐lactic acid (PLA) composites with glutaric acid functionalized titanium dioxide (TiO₂)

The performance of Poly(lactic acid) (PLA) composites reinforced with functionalized titanium dioxide (TiO 2 ) nanoparticles in rutile and anatase crystalline phases were systematically investigated. The results underline that the incorporation of TiO 2 , regardless of its crystalline structure, significantly enhances PLA's crystallinity by 85%. Notably, rutile TiO 2 , when functionalized with higher glutaric acid concentrations, was an effective crystallinity booster by 95%, passing from 20.39% to 39.58% crystallinity for the PLA/TiO 2 R20 + 10% system. Furthermore, this research elucidates that the selection between anatase and rutile phases plays a vital role in the photostabilization. Functionalized Rutile TiO 2 exhibited exceptional UV resistance, effectively inhibiting photodegradation; for example, after 15 days of exposure, the functionalized systems exhibited a 497.6% improvement for PLA/TiO 2 R10 + 5% (22.1 ± 2.5 MPa), while the PLA/TiO 2 R10 + 5% showed an 85.1% increase in composite stiffness (35.5 ± 3.5 MPa) after 7 days of degradation, in comparison with pristine PLA (19.2 ± 2.9 MPa). Anatase, conversely, displayed varying effects depending on concentration, acting as a stabilizer at lower levels and a promoter of degradation at higher concentrations. This knowledge enables the precise modifying of PLA composites for specific applications, balancing crystallinity, mechanical properties, and UV resistance for a diverse array of applications. Highlights TiO 2 enhances photostability in PLA confirming its potential as a UV stabilizer. Comparing anatase and rutile phase: Unveiling PLA composite dynamics. Glutaric acid on TiO 2 enhances PLA composite strength significantly. Optimal acid concentration key to composite performance. Tailored PLA composites balance crystallinity, mechanics, and UV resistance.