Study-of-a-paper-degradation-process-by-XAS-at-ID26-ESRF by asafwewe

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									                                              RICH
                                          Workshop on
                          Research Infrastructures for Cultural Heritage
                                  Trieste 12-13 dicembre 2005

        Study of foxing, a paper degradation process, by XAS at ID26-ESRF
                             A.Sodo1,2*, M.Bicchieri2 , Pieter Glatzel3, Thomas Neisius3
             1
               Department of Physics, University Roma Tre, Via della Vasca Navale 84, 00146 Roma, Italy
             2
               Laboratory of Chemistry, Istituto Centrale per la Patologia del Libro (I.C.P.L.),Via Milano 76, 00184
             Roma, Italy
             3
               ESRF, European Synchrotron Radiation Facility , 6 rue Jules Horowitz, BP 220, 38043 Grenoble,
             France

* sodo@fis.uniroma3.it


        XAS investigation was carried out at ID26-ESRF to understand foxing, a complex
mechanism occurring in paper. Foxing is a typical phenomenon of paper alteration, which appears as
spots of variable dimensions generally colored from lemon yellow to dark-brown with sharp or
irregular edges. The formation of foxing spots damage the paper, by compromising the conservation,
the aesthetic and the readability of the text or the artistic works.
        Two different mechanisms explaining the formation of foxing stains are currently accepted
by the scientific community: the “chemical” and the “microbiological” hypothesis [1]. Following
the latter, foxing is the result of some micro-organism based processes, while in case of the former,
foxing is the result of the oxidation of some elements that are always found in the centre of the
foxing stain. The most widespread chemical foxing is produced by the oxidation of iron. Evidences
for both mechanisms were found on paper [2].
        Aim of this work was to investigate by XANES measurements at Fe K edge (7.112 KeV) the
role of the iron ions in the formation of foxing and how it is linked to the paper.
        We investigated artificially induced foxing spots (some of these samples were aged to
simulate the natural ageing and part remained unaltered) and foxing spots from historical samples,
trying to understand the foxing formation dependence on iron ion oxidation state, concentration, and
kind of paper.
        Some first interesting results are shown, demonstrating that foxing is not dependent on the
concentration and oxidation state of the starting iron ion and on ageing but that it is strongly
dependent on the local structure of paper.


[1] Rebrikova N.L., Manturovskaya N.V., Restaurator, 85, (2000).
[2] Arai H., International Biodeterioration and Biodegradation, 46, 181 (2000)

								
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