Relationship between the passivation of TiO2 particles and LLDPE photodegradation: a comparison between bulk and surface impacts.

The effect of the concentration of alumina (Al2O3) and silica (SiO2) used to passivate titanium dioxide (TiO2) particles on the photodegradation of plastic films containing these particles was investigated. The films were made of linear low‐density polyethylene (LLDPE) containing four different types of passivated TiO2 particles. The UV degradation of the films was evaluated for the surface and the bulk by measuring the physical and chemical changes as a function of time. The surface chemical and physical degradation effects were measured by ATR‐FTIR and AFM, respectively. A statistical Gaussian adjustment was proposed to correlate the AFM depth profiles of the eroded surfaces of the films after the photodegradation process. The bulk physical effect was evidenced by the loss of mechanical properties in the films. The results showed that the higher the concentrations of Al2O3 are, the better the inhibition of the photodegradation of the LLDPE films. In this study, it was confirmed that the observed UV degradation effect correlated at both the surface and bulk levels. The results showed not only the reduction of the photodegradative effect as the passivation of the TiO2 particles increased but also the possibility of using these particles as UV stabilizers of LLDPE films. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47026. [ABSTRACT FROM AUTHOR]