Titanium dioxide-benzophenone hybrid as an effective catalyst for enhanced photochemical degradation of low density polyethylene

Abstract

In this study, a hybrid of titanium dioxide, benzophenone and ethylene vinyl acetate (TiO2-BP-EVA) was used as a novel catalyst to accelerate photo-oxidization reaction of low-density polyethylene (LDPE) film under ambient conditions. The degradation of the LDPE films (thickness of ~25 μm) containing different catalyst concentrations were successfully investigated by different techniques, such as Fourier-transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (SEM), differential scanning calorimetry (DSM), thermogravimetric analysis (TGA) and mechanical tests. The results showed that the use of catalyst in which TiO2-BP content (1/3 w/w) is 0.5 phr (parts per hundred resin) and EVA content is 4.5 phr in a LDPE film provided the best degradation rate. The carbonyl index of the polymer film achieved the highest value without an equilibrium stage. Besides, the carbon-carbon backbone of the polymer was completely broken down consistent with the deformation of the surface. In addition, the mechanical properties impressively dropped after 3 months' exposure. The obtained results imply that the TiO2-BP-EVA compound can be considered as an efficient catalyst for the photodegradation of LDPE polymer.