PSI - Issue 26

Chiara Bertolin et al. / Procedia Structural Integrity 26 (2020) 147–154 Bertolin et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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and this is compatible with the hydrophilicity of epoxy resins, where clusters of water molecules tend to be bigger and closer to each other. As anticipated S can also be obtained as S ads , and the comparison provided in Fig. 3 clearly shows how the values obtained in this way tend to be much less different each other than for values obtained as S GAB . The discrepancy can lead to an overestimation of t GAB , especially for RH>80%. At the opposite the GAB model underestimates the water thickness of the monolayer at RH< 30%.

4. Conclusions

The Guggenheim-Anderson-de Boer equation is applied to analysis carried out by means of a vacuum microbalance on a set of pine wood samples coated on the radial surface with different materials able to limit the penetration/expulsion of moisture. Changes in the k GAB , C GAB , V ads and S GAB parameters were evaluated and explained in terms of modifications of the strengths of bonds formed between the surface and first water layer and consequently between it and the following ones up to the last deposited layer (liquid phase). These variations are also related to the surfaces water repellency affecting the possibility of water molecules to form clusters more or less distant each other. Acknowledgements The researc h activity has been realized in the frame of the “SyMBoL – Sustainable Management of Heritage Building in a Long- term Perspective” Project (Project No. 274749) founded by the Norwegian Research Council. This research was funded in part by the statutory research fund of JHICSC PAS. Akin I.D., Likos W.J., 2014. Specific surface area of clay using water vapor and EGME sorption methods. Geotechnical Testing Journal 37, 1016-1027. Almeida G., Gagné S., Hernández R.E., 2007. A NMR study of water distribution in hardwoods at several equilibrium moisture co ntents, Wood Science and Technology, 41, 293- 307. Andrade P. R.D., Lemus M. R., Perez C. C. E., 2011. Models of sorption isotherms for food: uses and limitations. Vitae, revista de la facultad de quimica farmaceutica, 18, 325-334. Arthur E., Tuller M., Moldrup P., Greve M.H., Knadel M., de Jonge L.W., 2018. Applicability of the Guggenheim-Anderson-Boer water vapour sorption model for estimation of soil specific surface area, European Journal of Soil Science, 69, 245-355. Arthur E., Tuller M., Moldrup P., Resurreccion A.C., Meding M.S., Kawamoto K. Komatsu T., de Jonge L. W., 2013 Soil specific surface area and non-singularity of soil-water retention at low saturations. Soil Science Society of America Journal, 77, 43-53. Bertolin C., de Ferri L., Grottesi G., Strojecki M., 2020. Study on the conservation state of wooden historical structures by means of acoustic attenuation and vacuum microbalance. Wood Science and technology 54, 203-226. Bratasz Ł., Kozłowska A., Kozłowski R., 2012. Analysis of water adsorption by wood using the Guggenheim -Anderson-de Boer equation, European Journal of Wood and Wood Products 70, 445-451. Broda. M., Majka J., Olek, Mazela B., 2018. Dimensional stability and hygroscopic properties of waterlogged archeological wood treated with alkoxysilanes. International Biodeterioration & Biodegradation 133, 34-41. Camuffo D., 2019. Microclimate for Cultural Heritage. Measurement, Risk Assessment, Conservation, Restoration, and Maintenance of Indoor and Outdoor Monuments , 3rd ed. Elsevier. de Ferri L., Strojecki M., Bertolin C., Preliminary results on surface treatments on wood, IOP Conf. Series: Materials Science and Engineering, in press. de Oliveira G.H.H., Correa P.C., de Oliveira A.P.L.R., Devilla I.A., 2017. Application of GAB model for water desorption isotherms and thermodynamic analysis of sugar beet seeds, Journal of Food Process Engineering, 40, e12278. Esteves B.M., Pereira H. M., 2009. Wood modification by heat: a review. Bioresources, 4, 370-404. Hailwood A. J. and Horrobin S., 1946. Absorption of Water by Polymers, Transactions of the Faraday Society. 42B, 84-92. Hakkou M., Petrissans M., Zoulalian A., Gerardin P., 2005. Investigation of wood wettability changes during heat treatment on the basis of chemical analysis, Polymer Degradation and Stability 89, 1-5. Kumar S., 1994. Chemical modification of wood, Wood and Fiber Science. 26, 270-280. Leao T.P., Tuller M., 2014. Relating soil specific surface area, water film thickness, and water vapor adsorption. Water Resources Research 50, 7873-7885. Lesar B., Gorisek Z., Humar M., 2009. Sorption properties of wood impregnated with Boron compounds, sodium chloride and Glucose. Drying Technology 27,94-102. McMinn W.A.M., Magee T.R.A., 1997. Moisture Sorption Characteristics of Starch Materials, Dry Technology 15,1527-1551. Quirijns E.J., van Boxtel A.J.B., van Loon W.K.P., van Straten G., 2005. Sorption isotherms, GAB parameters and isosteric heat of sorption, References