Influence of Gum Arabic on Iron Gall Ink Corrosion Part I: A Laboratory Samples Study
| Hlavní autori: | , , |
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| Médium: | Článok |
| Jazyk: | angličtina slovenčina |
| On-line prístup: | http://www.viks.sk/chk/res_4_04_220_232.doc |
| Abstrakt: | SUMMARY. In the Western world, Gum Arabic has been extensively used as a binder in iron gall ink preparation. Its impact on iron gall ink corrosion of paper was investigated on laboratory samples. These samples comprised cotton linters cellulose paper (no charge, no fillers, no size) impregnated with different solutions combining the three main ingredients of iron gall ink, these being gallic acid, iron sulphate and Gum Arabic. The paper degradation caused artificial ageing was evaluated by colour measurements, mechanical test and FTIR spectrometry. It was observed that, in the presence of Gum Arabic, cellulose degradation induced by the presence of iron was delayed. This observation can be interpreted in several ways: first, the gum may physically protect the paper, by coating the paper fibres, and thus limiting the diffusion of free iron II. Secondly, the gum could be interacting chemically with iron II and is degraded by the iron(II) rather quickly. Also, the free iron II ions, which are involved in Gum Arabic corrosion, may not then be involved in the catalysis of the cellulose oxidation. CONCLUSION. All our measurements lead to the same conclusion: the presence of Gum Arabic limits the degradation of cellulose, thus delaying the weakening of the paper induced by iron gall ink corrosion. This observation may have several interpretations. Firstly, this behaviour may be due to a physical effect. The paper used for the samples was not sized. During the impregnation process, the gum penetrated deep into the paper, coating the fibres, and thus limited the diffusion of free iron in the fibres. Secondly, this protective influence may also be due to a chemical effect. The gum was sensitive to the presence of iron II. It degraded rapidly and turned brown. Also, the presence of gum in the ink led to more saturated colour. We may then suppose that the free iron ions, which are involved in Gum Arabic corrosion, may not be involved in the catalysis of the cellulose oxidation. To confirm these assumptions, it appears necessary to look at original manuscripts written with iron gall ink. How can Gum Arabic be identified in them? How does it behave during real ageing? Does it really delay the degradation of paper? We will present in the second part of this article the work we did in order to answer some of these questions |
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| ISSN: | 0034-5806 |
