The Effect of Nd:YAG Laser Radiation at 1064 nm on Paper
| Hlavní autori: | , , |
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| Médium: | Článok |
| Jazyk: | angličtina slovenčina |
| On-line prístup: | http://www.viks.sk/chk/res_1_00_9_18.doc |
| Abstrakt: | CONCLUSION. Laser treatment of Whatman as well as gelatine sized rag paper increased DP values of samples. This suggests that irradiation of paper induces formation of inter-molecular cross-links between cellulose molecules, which is supported by an increase in absorption bands ascribed to ether bonds in diffuse reflectance FTIR spectra. No discernible difference in spectra around 1730 cm-1 indicate that change in content of acidic or carbonyl groups during laser treatment under described conditions is below threshold sensitivity of the method. It appears that irradiation of paper with laser beam at 1064 nm stabilised Whatman filter paper during accelerated ageing, as brightness and DP values of the treated samples remained higher than the untreated control. Results were different for gelatine sized rag paper as the brightness and DP after 6 days of accelerated ageing at 90°C and 65% RH were slightly lower in case of treated papers. Results presented here indicate that Nd:YAG laser at 1064 nm is a potentially useful tool in paper conservation. However, before the method may be applied to historical documents, additional information must be obtained, especially regarding the effects that it exhibits on mechanical properties of paper. Additional studies must also incorporate a variety of different paper samples, as well as the effect on iron-gall ink regions. This work is in progress. SUMMARIES. Immediate as well as long term effects of Ng:YAG laser irradiation at 1064nm, pulse duration of 6 ns and fluence up to 1.5 Jcm-2 on paper is reported. Results of diffuse reflectance FTIR spectroscopy show no discernible difference in the regions around 1730 cm-1 indicating that change in content of acidic or carbonyl groups during laser treatment under described conditions is below threshold sensitivity of the method. However, positive absorption bands as a result of laser treatment may be ascribed to C-O and C-O-C vibrations, suggesting the formation of intra- and intermolecular ether bonds. Results of DP are in accordance with DRIFT spectroscopy, as the cross-linking of cellulose during the treatment results in an increase of DP of cellulose. |
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| ISSN: | ISSN 0034-5806 |
