Study of the Photo-oxidation and Photolysis of Unsaturated and Cross-linked Polyesters (UP) in the Presence of Photoactive or not Inorganic Fillers

AbstractDisturbances of the photochemical evolution involved in the photolysis and in the photo-oxidation at long wavelengths (ë?300nm) of poly(propylene glycol-maleatophtalate cross-linked by the styrene (UP),caused by the addition of photo-active pigment such as zinc sulphide or black iron oxides,and no photoactive inorganic fillers such as calcium carbonate have been analysed by means of FTIR and U.V. spectrophotometry.The photo-oxidation observed by FTIR of the polymer UP in the presence of inorganic fillers leads to the same photoproducts such as ones of the photo-oxidation of the virgin polymer, but the oxidation rate is greatly affected by the nature and the percentage of the inorganic filler. Zinc sulfide and black iron are incorporated in the film of polymers, the absorption spectra of ZnS reveals that this pigment is not as absorbent as titanium oxide in a more limited field. On the other hand, with a very low inner filter effect, black iron oxides promote the formation of absorbing photoproducts. The addition of Calcium carbonate non- absorbing filler to the UP, causes a slight decrease in the evolution of the I.