Investigation of polymera??based composites by laser desorption ionization Study of their photoa??oxidative aging

摘要： RATIONALE The polybutadiene (PB) is one of the most widely used polymers. Its aging occurs by reaction with oxygen under illumination and may modify its mechanical and/or aesthetic properties. To modify its properties, organic and/or inorganic compounds are generally added to the PB. The aging of such composite materials is poorly known. METHODS The PB and its mixtures with TiO2 and/or the Orange 13 pigment are subjected to an accelerated photo-oxidative aging step for one week. The analysis of PB and its composites with regard to their composition and the aging time, is carried out by 266 nm and/or 355 nm laser/desorption ionization Fourier transform ion cyclotron resonance mass spectrometry (LDI FT ICR–MS). RESULTS Both PB and its degradation products are detected by (+) LDI FT–ICR MS. The oxidation mechanism of the PB is not significantly affected by the used organic or inorganic fillers, which results from the cleavage of the polymer chain and the formation of carbonyl compounds. The crosslinking of the PB is significantly reduced by the two investigated fillers. The (–) LDI FT–ICR MS ensure the specific detection of the Orange 13 pigment. CONCLUSIONS LDI FT ICR - MS has demonstrated its ability to provide relevant information on the degradation of polymer-based composites. The main advantages of this approach are its ability to probe the surface, which is specifically affected by photo-oxidation aging processes, and to access the insoluble degradation compounds.