Summary: The degradation of an epoxy/amine resin was studied under photolytic conditions in absence and in presence of oxygen and under thermooxidative conditions. The resin is obtained after curing the diglycidyl ether of bisphenol‐A (DGEBA) with a poly(propylene glycol) which is diamine terminated. The mechanisms of degradation of the two separate components before curing were also investigated. Analysis by IR and UV‐Vis spectroscopies revealed that the oxidation photoproducts detected during the degradation of the epoxy/amine result from the oxidation of the DGEBA part, of the amine crosslinks and, to a lower extent, of the poly(oxypropylene) units. Their mechanism of formation essentially involves chain scission reactions. During irradiation, the yellowing observed is mainly due to the formation of a quinone methide structure. Thermooxidation generates high discoloration with some products only generated in that case. For all experiments, a detailed analysis of the IR spectra is given with the chemical mechanisms of formation of the degradation products.ATR‐IR spectra of an epoxy/amine sample in the carbonyl region during photooxidation.magnified imageATR‐IR spectra of an epoxy/amine sample in the carbonyl region during photooxidation.

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.

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Layered double hydroxide (LDH) organo-modified by a surface-active monomer, 3-sulfopropyl methacrylate (SPMA) was used as filler for polystyrene (PS). Different nanocomposites SPMA/LDH:PS were prepared by bulk polymerization process using low amount of initiator. The two components, filler and polymer, as well as the degree dispersion of the reactive filler as a function of its loading in PS were characterized by a combination of several techniques: X-ray diffraction, high resolution 13 C CP-MAS NMR, FTIR, UV-visible, thermal analysis, SEC and MET. The nanocomposites were submitted to UV-light exposures in the presence of oxygen. The oxidation photoproducts and the rates of oxidation were compared for the various samples. It was shown that the filler was not modifying the oxidation mechanism of the polymer, but had a slight effect on the oxidation rate.

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