A Method for the Non-Destructive Analysis of Paper Based on Reflectance and Viscosity
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English Slovak |
| ISSN: | ISSN 0034-5806 |
| Online Access: | http://www.viks.sk/chk/res_4_01_187_207.doc |
| Abstract: | Summaries. During research to assess the effectiveness of the mass deacidification treatment developed at the Universitat Politecnica de Catalunya (UPC-ETSIIT-Spain), the changes produced in several chemical and physical properties of papers dating from the 17th, 18th and 19th centuries were compared, particularly the changes in viscosimetric degree of polymerization and colour parameters (lightness, chroma, and hue) caused by ageing and deacidification. A good statistical correlation between the colour differences of each sample versus a pure cellulose reference sample and the degree of polymerization for the same samples was observed. These findings will permit the use of the colorimetric method and the viscosimetric method for monitoring the conservation level of book and archival paper. It was also observed that -E and DPv ranges under determined ageing conditions depend on the type of paper and its composition; so these properties could be used for the characterisation of papers by their age and manufacturing system. Conclusions. The retention values of lightness and of degree of polymerization in the deacidified samples clearly show that the UPC mass deacidification treatment has a distinct, positive effect on the ageing behaviour of paper. The alkaline buffer that is brought into the paper by this process inhibits the degradation processes. It has been demonstrated that the colour difference AE correlates well with the viscosimetric DPv, at least within ranges determined by the accelerated ageing test conditions (0-21 days at 90°C and 50% RH) These and similar results can be used to define a method for non destructive analysis of papers, comprising the following steps: ˙ determinate the degree of polymerization of the paper by taking 5 or 6 small test specimens, weighing less than 200 mg at random. The paper sample should be washed previously in a diluted acidic bath in order to make the viscosimetric analysis more accurate. The results will be better in papers with the least amount of additives, sizings, coatings and lignin. Generally it may be enough to determine the DPv of a non-aged untreated paper only, but it would be more accurate to measure that of the most aged sample, too. ˙ obtain some different levels of paper degradation by means of different accelerated ageing periods. ˙ measure the colour of all the samples, aged and unaged. ˙ calculate the other degrees of polymerization, not determined by viscosity, by applying the regression equation DPv/E previously found in a paper of similar characteristics. |
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| ISSN: | ISSN 0034-5806 |
