Surface modification of polylactic acid using a photo-activated chlorine dioxide process: surface properties and dissimilar adhesion

In this study, we examined the modification of polylactic acid (PLA) plates and powders using a photo-activated chlorine dioxide (ClO₂˙) treatment. Changes in the degree of oxidation depending on the oxidation conditions, namely, temperature and time, were determined by surface elemental analysis using X-ray photoelectron spectroscopy and quantification of the number of carboxy groups using toluidine blue O staining. Oxidized PLA exhibited excellent adhesion to dissimilar materials, including aluminum and cellulose. In the adhesion to aluminum, the relationship between the adhesion strength and oxidation degree was investigated.