Structure of Paper Fibres in Ancient Manuscripts: Acidic Decomposition and Deacidification
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| Format: | Article |
| Language: | English Slovak |
| Online Access: | http://www.viks.sk/chk/res_2_96_117_129.doc |
| Abstract: | Conclusions. The first results of comparing several samples with fibres degraded by acidic inks led us to the following conclusions. Catalan papers from the 14th century have long fibres without shredded edges. The fibres of documents from the 16th century are more shredded. The sizing for documents before 1350 in the Chancery Section was made with starch glue. In later papers we found both animal and starch glue up to the end of the 15th century when only animal glue was found. Fibres are broken when the paper is very acidic, although the craftsmen were very good at manufacturing the ancient paper. We tested this by optical and SEM images. Tensile strength and other physical and mechanical properties can change when paper is soaked in a water bath and then in deacidificant solutions. We obtained better results with calcium-magnesium bicarbonate solutions than with calcium hydroxide. It is established that magnesium bicarbonate destroys the sizing of old papers, but the effects of the high pH of calcium hydroxide on the cellulose chains are worse. The improvements in the physical and mechanical properties were probably due to the fact that as the oxidized acidic products in very acidic paper are solubilized, sulphur disappears. The acidic groups in the cellulose chains were coupled with the alkaline metals such as Ca and Mg. We found the magnesium-calcium bicarbonates gave better results. This work is still in progress. We hope to do further tests to identify the optimum calcium-magnesium bicarbonate ratio. We used 0.05M Mg (HCO3)2. We found that the amount of calcium in the bicarbonate solution is also important. Summaries. Fibres in paper documents from the 14-18th centuries are mostly of linen or hemp. Two deacidification processes on several manuscript samples were tested. One used a semi-saturated aqueous calcium hydroxide solution and the other calcium and magnesium bicarbonates. The aim of this work was to compare these two solutions in rag paper documents deteriorated by iron-gall ink. The results showed that the calcium and magnesium bicarbonates produced better improvements in the paper and in the iron-gall ink than the calcium hydroxide solution. The best results were obtained with a calcium:magnesium ratio in the bicarbonate solution of 5:1. Among other results, we noted the following. The blend of bicarbonate resulted in a lower pH than the calcium hydroxide. The high solubility of the calcium and magnesium bicarbonates helped to give the paper a good alkaline buffering. The magnesium improved the paper permanence. |
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| ISSN: | ISSN 0034-5806 |
