FrançaisCICRP – Centre Interrégional de Conservation et Restauration du Patrimoine
[CICRP - Interregional Centre for Heritage Conservation and Restoration]
Limitations of Raman spectroscopy
in the degradation assessment of
polyurethane artworks
Authors : Alain Colombini and Vicente Léal Romero (master, Madrid)
Poster presented at the Lacona VII conference in Madrid in 2007.
Download this poster in PDF (593 kilo octets).
Abstract :
Since the early eighties, artist have used polyurethane elastomers as paint, binder, adhesive and foam. As the relevant works of art now appear in public collections, it is important to characterize and to study the behaviour of these polymers in order to understand both the ageing and the interaction with other materials. Severe weathering accelerated ageing conditions were purposely used in this study, as this can be related to stressful environment surrounding works of art, in particular polyurethane painted foam sculptures exhibited in public places. Photo degradation of such polymers occurs rapidly. The mechanism of degradation is mainly caused by both oxidation and hydrolysis. The increase of the carbonyl during ageing process is a sign of the oxidative degradation of the polyurethane, in particular that of the polyether based polyol. The ability of Raman spectroscopy to assess the various degradation processes involved is discussed.
Raman spectroscopy has shown some limitations in the assessment of the chemical modifications which occur during the ageing process.
Nevertheless, it remains an efficient technique in the identification of the main components of polyurethane. It has also been demonstrated that the use of photobleaching and improving the sample preparation are preponderant for enhancing the quality and the reliability of Raman spectra.
Page mise à jour le 3 octobre 2007.
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