Preparation of degradable polypropylene by an addition of poly(ethylene oxide) microcapsule containing TiO2

In order to prepare a novel photo-degradable polypropylene (PP), an addition of poly(ethylene oxide) (PEO) microcapsule containing TiO2 to PP was performed. Adsorbed H2O in the PEO phase and the TiO2 photocatalytically reacted, and a hydroxyl radical (OH center dot), which initiated the PEO degradation, was produced. The degraded PEO produced an acid and an aldehyde, which were able to facilitate PP degradation. The addition of the PEO/TiO2 microcapsule brought about the facilitative effect of the PP degradation. In addition, an addition of a hindered amine light stabilizer (HALS) had a potential to suppress the PP degradation initiated by the microcapsule. The suppression effect was rising by the simultaneous addition of a phenolic antioxidant in the early phase of the PP degradation. However, the simultaneous addition showed an antagonism after 4 h degradation. This behavior suggested that the HALS also worked as a neutralizer of the produced acid. (C) 2009 Elsevier Ltd. All rights reserved.