Abstract
The applications of biodegradable polylactide (PLA) are dependent on its structural durability under service conditions. In this work, we analyze the temperature dependence of photo-stability of polylactide-poly(methyl methacrylate) (PLA/PMMA) blends after the irradiation of ultraviolet (UV) light. X-ray diffraction analysis of the UV-irradiated PLA reveals the crystalline phase formation at 55 °C, as confirmed by thermal analysis. The UV irradiation decreases the crystallization temperature of PLA. The thermal analysis and Fourier Transform Infra-Red (FT-IR) analysis illustrate the interaction between PLA and PMMA. We evaluate the photo-stability of the UV-irradiated PLA/PMMA blends from the temporal evolution of optical absorbance/transmittance of the blends. A first-order kinetic analysis is used to analyze the change of optical absorbance, controlled by the annihilation and generation of color centers. Two processes contribute to the photo-stability of the PLA/PMMA blends – one is annihilation-dominant for the blends with a large fraction of PMMA, and the other is generation-dominant for the blends with a large fraction of PLA. The combinational effect of UV irradiation and the interaction between PLA and PMMA determines the photo-stability of PLA/PMMA blends.
UV–Vis transmittance change of UV-irradiated PLA/PMMA. [Display omitted]
•Photo-response of polylactide-poly(methyl methacrylate) blends is studied.•Ultraviolet irradiation affects the optical absorbance of the polymer blend.•A kinetic model for the color center formation is proposed.•Color centers are generated in PLA and annihilated in PMMA, respectively.•The rate constants of color centers follow the Arrhenius plot.