Photooxidation of Polypropylene/Montmorillonite Nanocomposites. 2. Interactions with Antioxidants

Abstract

The influence of stabilizing additives on the photooxidation of polypropylene/montmorillonite (PP/ MMt) nanocomposites exposed to UV light was studied. Two different stabilizers were used, a phenolic antioxidant and a redox antioxidant. A significant reduction in the induction period of oxidation was observed in the presence of MMt. This is believed to arise from interactions between the additives and the nanoclay. The interactions could involve the adsorption of additives onto the clay, the degradation of the alkylammonium cations exchanged in MMt, and the catalytic effect of iron impurities of the organomontmorillonite. Iron could catalyze the decomposition of the primary hydroperoxides formed by photooxidation of PP, which would in turn accelerate the additive consumption and decrease the length of the period before the permanent regime of oxidation is reached.

Effect of Metal Acetylacetonates on the Photooxidative Destruction of High Density Polyethylene

“…This allows for formation of shorter fragments which more easily crystalize in the polymer matrix. It is confirmed by other authors 23,24 . Figure 1 a shows the FT-IR spectra of foils from initial and UV irradiated HDPE.…”

Boosting TiO2-anatase antimicrobial activity: Polymer-oxide thin films

“…220 nm ascribed to cromophores (phenolic antioxidants and/or PP degradation products) coming from its industrial origin [28], the TiO 2 -related features appears barely visible for low loadings but become clearly visible for the Ti5 specimen. The onset of this broad feature occurs at ca.…”

New Composite Materials in the Technology for Drinking Water Purification from Ionic and Colloidal Pollutants

“…Polypropylene/montmorillonite nanocomposites, additionally stabilized with antioxidant, degrade much faster under photo-oxidative conditions than pure polypropylene [25,26].This phenomenon is attributed to active species/sites in the clay generated by photolysis or photo-oxidation, and by consequence interaction between antioxidant, montmorillonite and maleic anhydride modified polypropylene. In natural clay present iron may additionally play an active role in the dramatic modification of material oxidation conditions [27], and nanoparticles also catalyze the decomposition process [28].…”