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Old paper characterization by optoacoustic measurements and vibration spectroscopyтезисы доклада
- Авторы: Brandt N.N., Balakhnina I.A., Chikishev A.Yu, Pelivanov I.M., Rebrikova N.L.
- Сборник: Proceedings of 6th Finnish-Russian Photonics and Lasers Symposium PALS'13
- Тезисы
- Год издания: 2013
- Место издания: Joensuu University of Eastern Finland, Department of Physics and Mathematics, Finland
- Первая страница: 40
- Последняя страница: 41
- Аннотация: In spite of the extensive application of digital data storage, paper remains to be one of the most widely spread materials. Paper materials are made of various cellulose fibers that differ from each other by fiber length and structure. In addition to cellulose fibers, paper materials contain fillers that provide bleaching, mechanical strength, etc. Note that predominantly natural fillers (gypsum and chalk) were employed up to the 1950s whereas artificial chemical components are added to modern papers. It is known that old paper materials exhibit degradation due to the oxidation of three hydroxyl groups in the cellulose molecule in the presence of atmospheric oxygen. The oxidation leads to the formation of new functional groups (carbonyl and carboxyl) [1], which results in the discoloration of paper. Different paper materials exhibit different degradation processes. Wood-pulp paper is the most unstable paper with respect to the oxidation, and cotton paper can be stored over relatively long time intervals in the absence of the discoloration. The formation of foxing stains is also observed on aged papers [2]. In accordance with the biological interpretation, the foxings result from the vital activity of fungi. In the chemical concept, the foxings emerge due to additional local oxidation of paper that is catalyzed by metal (iron and copper) ions sedimented on the paper surface. Both hypotheses are in agreement with the experimental data. Various methods can be employed in the paper study. Note that the noninvasive procedures are preferred in the experiments with historically important samples. Evidently, the chemical analysis can be inapplicable and the physical methods (IR and Raman spectroscopy, optoacoustic spectroscopy, X-ray analysis, and ultrasonic methods) can be used. The noninvasive character of the measurements must be supplemented with relatively high sensitivity and resolution. IR spectroscopy is a conventional tool in the paper study [1, 3-5]. The IR spectra of paper are well interpreted [3-7]. It is known that the cellulose oxidation leads to the spectral changes in interval 1500-1800 cm-1, where the spectral features assigned to the carbonyl and carboxyl groups are manifested [1, 6-7]. Raman spectroscopy can be used to additionally characterize the molecular composition of paper samples [8]. The advantage of the Raman analysis lies in a relatively high sensitivity to the skeletal vibrations of the cellulose molecule. Optical characteristics of paper are also intensively studied [9-11]. In spite of the application of various methods, only few works are devoted to the comparison of the optical properties of the foxed and unfoxed papers. In this work, we compare several foxed and unfoxed samples using FTIR spectroscopy (Nicolet 6700 FTIR spectrometer interfaced with a Smart Orbit attenuated total reflectance unit), Raman microspectroscopy (DXR Raman Microscope), and opto-acoustic measurements [12]. The last method makes it possible to calculate the paper porosity and to determine the speed of sound in the cellulose fibers. Raman and IR experiments show that the intensities of the vibrational bands in the spectra of foxings are significantly greater in the spectral interval 1500-1800 cm-1 than the intensities of the bands corresponding to the foxing-free regions. We calculate the porosity of paper samples using the measured velocities and employing the theory of two-phase mixture. Within experimental error, the porosity of paper in foxings is no less than the porosity of unfoxed paper. The difference of the corresponding porosities for samples P001 and P002 is 12-15 %. This result indicates significant modification of paper in foxings. [1] R.G. Zhbankov, Infrared Spectra of Cellulose and its Derivatives, (New York. N. Y. U. S. A., 1966). [2] S. Choi, J. of the American Institute for Conservation 46, (2007). [3] M. Manso, M.L. Carvalho, Spectrochimica Acta Part B 64, (2009). [4] P. Calvini, A. Goassini, Restaurator 23, (2002). [5] J. Lojewska, A. Lubanska, P. Miskowiec, T. Lojewski, L.M. Proniewicz, Applied Physics A: Materials Science and Processing 83, (2006). [6]J. Lojewska, A. Lubanska, T. Lojesewski, P. Miskowiec, L.M. Proniewicz, Preservation Science 2, (2005). [7] P. Calvini, M. Silveira, Preservation Science 5, (2008). [8] M. Bicchieri, A. Sodo, G. Piantanida and C. Coluzza, J. Raman Spectroscopy 37, (2006). [9] M.C. Beland, J.M. Bennett, Applied Optics 39, (2000). [10] T.R. Lettieri, E. Marx, J.-F. Song, T.V. Vorburger, Applied Optics 30, (1991). [11] J. Carlsson, P. Hellentin, L. Malmqvist, A. Persson, W. Persson, C-G. Wahlstrom, Applied Optics 34, (1995). [12] A.A. Karabutov, I.M. Pelivanov, N.B. Podymova, Acoustical Physics 51, (2005).
- Добавил в систему: Брандт Николай Николаевич