The combined effect of H2O2 and light emitting diodes (LED) process assisted by TiO2 on the photooxidation behaviour of PLA. (February 2019)

• Record Type: Journal Article
• Authors: Martín-Alfonso, J.E.; Urbano, Juan; Cuadri, A.A.; Franco, J.M.
• Is Part Of: Polymer testing. Volume 73(2019)
• Page Start: 268
• Page End: 275
• Publication Date: 2019-02
• Subjects: Polylactic acid -- Hydrogen peroxide -- Photo-oxidation -- Chemical properties -- Thermal properties; Polymers -- Testing -- Periodicals; Polymères -- Tests -- Périodiques; 620.1920287
• DOI: 10.1016/j.polymertesting.2018.11.031
• Languages: English
• ISSNs: 0142-9418

Abstract

Abstract: The overall objective of this work was to study the combined effect of hydrogen peroxide (H2 O2 ) and light emitting diodes (LED) process assisted by titanium dioxide (TiO2 ) on the photo-oxidation behaviour of polylactic acid (PLA). The photochemical behaviour of PLA in a TiO2 suspensions was studied by irradiation under photo-oxidative conditions (λ > 454 nm, ambient temperature and with or without the presence of H2 O2 ). The chemical and thermal properties induced by LED irradiation process were analyzed using fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance ( 1 H NMR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It was found that the presence of photoactive TiO2 particles, combined with H2 O2 leads to strong impact on the physicochemical properties of the samples during photochemical ageing. A new comprehensive mechanism for the photo-oxidation of PLA for these conditions was discussed. Highlights: Role of H2 O2 and LED process assisted by TiO2 on PLA photo-oxidation. Chemical and thermal properties are in agreement with degradation degree. PLA degradation evolution followed by FTIR and 1 H NMR results. Photo-oxidation process leads a significant molecular weight reduction. A new comprehensive mechanism for PLA photo-oxidation was proposed.