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In this paper, we first outline the Thales EC-supported project INVENVORG, which investigates the effects of the environmental factors on non-treated organic materials, namely bone, woolen textile, parchment, paper and wood. The project planning includes an accelerated ageing study (with exposure to elevated temperatures and relative humidities, light and pollutants) and then a natural ageing study in monitored museums environments, followed by the statistical correlation analysis of the material properties after accelerated and natural ageing with the environmental stresses, in order to determine the real life relative contribution of the various environmental parameters to material ageing. After a literature review concerning the exhaustive research on the accelerated ageing of paper, the experimental design pertaining to paper is presented. Accelerated ageing will be used for the production of artificially aged samples that emulate aged paper in a controlled manner. A preliminary ageing experiment will help determine the most suitable conditions, and will provide data that will be correlated to those produced by natural ageing. Virgin and artificially aged samples will then be exposed for 2 years to closely monitored museums environments. Tearing strength, degree of polymerization determined by viscometry, pH and the color coordinates of the CIEL*a*b* colour system will be determined and used for the statistical analysis.

The optical properties and degradation of fir wood treated by different inorganic salts, which are components of waterborne wood preservatives, were studied before and after wet-thermal accelerated ageing (T=85 degrees C, RH=65%, for 30 days) using UV-Vis diffuse reflectance spectroscopy. The colour of all impregnated samples was due to the same chromophoric structures, thus revealing that the primary reactions leading to colour changes are essentially very similar. These chemically treated as well as standard (non-treated, unaged) and reference (treated only with distilled water, unaged/aged) samples have a significant absorption band at 358 nm, along with a shoulder near 265 nm of various intensity. The broad band at higher wavelength is attributed to the chromophoric structures derived especially from lignin, i.e. quinones, stilbenes, charge transfer complexes causing a bathochromic shift and other conjugated carbonyl structures. Coniferaldehyde is also a major contributor to this absorption. The band at 265 nm belongs to chromophores arising predominantly from carbohydrate degradation products, i.e. furan derivatives, quinone-type derivatives, catechol structures. Catechol structures (colourless) form coloured complexes with transition metal cations (Cu2+, Fe3+) or are oxidized to form highly coloured benzoquinone structures. Alkaline solutions of borax cause the reduction of conjugated and non-conjugated carbonyls and the degradation of coniferaldehyde. Generally, after ageing, the samples show higher absorptions in the visible region of the spectra in comparison. with the unaged ones, which explains their yellowing and loss of brightness after the action of elevated temperature and moisture.

International audience; Brown lines were generated at the wet-dry interface on Whatman paper No. 1 by suspending the sheet vertically in deionized water. Formic acid and acetic acid were quantified in three areas of the paper defined by the wet-dry boundary (above, below, and at the tideline) using capillary zone electrophoresis with indirect UV detection. Their concentration increased upon accelerated aging of the paper and was highest in the tideline. The hydroperoxides have been quantified using reverse phase high performance liquid chromatography with UV detection based on the determination of triphenylphosphine oxide produced from the reaction with triphenylphos-phine, and their highest concentration was found in the tideline as well. For the first time, it was shown that various types of hydroperoxides were present, water-soluble and non-water-soluble, most probably in part hydroperoxide functionalized cellulose. After accelerated aging, a significant increase in hydroperoxide concentration was found in all the paper areas. The molar masses of cellulose determined using size-exclusion chromatography with multiangle light scattering detection showed that, upon aging, cellulose degraded significantly more in the tideline area than in the other areas of the paper. The area below the tideline was more degraded than the area above. A kinetic study of the degradation of cellulose allowed determining the constants for glycosidic bond breaking in each of the areas of the paper.