Photocatalytic Degradation of Polyethylene Plastic with Polypyrrole/TiO₂Nanocomposite as Photocatalyst

The photocatalytic degradation of polyethylene (PE) plastic was carried out directly under the sunlight irradiation with polypyrrole/TiO2 (PPy/TiO2) nanocomposite as photocatalyst, which prepared by sol-gel and emulsion polymerization methods. The photocatalytic degradation efficiency was determined by weight loss monitoring, gel permeation chromatography (GPC), atomic force microscopic (AFM) and FT-IR analysis. The photocatalytic degradations of PE plastic with pure TiO2 and PPy were also investigated and compared with that of PPy/TiO2. It was noticed that irradiating the PE plastic for 240 h by sunlight reduced its weight up to 35.4% and 54.4% of M w, respectively. The AFM images showed the formation of cavities on PE plastic surface. FT–IR spectroscopic studies indicated that a strong interaction existed between the interface of PE and PPy/TiO2 and caused the degradation of PE. The photocatalytic degradation mechanism was also discussed briefly.