Abstract
Whether water sorption hysteresis exists above 75 °C and the representation of its relationship with wood softening remains unclear. In this study, sorption hysteresis at three temperature levels, namely, 75, 90 and 99.5 °C, was investigated using accurately controlled conditioning chambers using powder samples from seven wood species. The dry mass loss percentage of the samples and proper equilibrium time was evaluated by pretests to ensure reliable sorption isotherms afterwards. The dry mass loss percentage after the entire sorption isotherm running needs to be kept within 0.5% to avoid complications in determining the equilibrium time. The abrupt increase of equilibrium moisture content at high relative humidity regions and the crossover of adsorption isotherms were not observed. Hysteresis was conspicuous at 75 and 90 °C and was statistically confirmed at 99.5 °C. High sample extractives content or unnecessarily long equilibrium time would cause significant sample dry mass loss, which may suppress the desorption isotherm to an extent that leads to unjustified hysteresis disappearance. The hysteresis behavior observed in this study suggests that wood softening does not necessarily result in hysteresis disappearance, and the explanation of hysteresis progression as a function of wood softening temperature must be evaluated with care in the future.
Funding source: Akita Prefectural University
Funding source: Nanjing Forestry University
Award Identifier / Grant number: 163020200
Acknowledgments
The sharing of the original sorption isotherm data of sikkim spruce (Picea spinulosa Griff.) from Prof. Jinzhen Cao at Beijing Forestry University is greatly appreciated.
Author contribution: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: The experimental work was funded by the Institute of Wood Technology at Akita Prefectural University and the preparation of the manuscript was funded by a research startup grant 163020200 from Nanjing Forestry University.
Conflict of interest statement: The authors declare no conflicts of interest regarding this article.
References
Avramidis, S. (1992). Enthalpy-entropy compensation and thermodynamic considerations in sorption phenomena. Wood Sci. Technol. 26: 329–333, https://doi.org/10.1007/bf00226074.Search in Google Scholar
Cao, J.Z. (2001). Interaction between water and wood during adsorption and desorption processes-from dielectric and thermodynamic approaches. PhD thesis. Beijing Forestry University, Beijing, China.Search in Google Scholar
Chen, M., Coasne, B., Guyer, R., Derome, D., and Carmeliet, J. (2018). Role of hydrogen bonding in hysteresis observed in sorption-induced swelling of soft nanoporous polymers. Nat. Commun. 9: 3507, https://doi.org/10.1038/s41467-018-05897-9.Search in Google Scholar PubMed PubMed Central
Fredriksson, M. and Thybring, E.E. (2018). Scanning or desorption isotherms? Characterising sorption hysteresis of wood. Cellulose 25: 4477–4485, https://doi.org/10.1007/s10570-018-1898-9.Search in Google Scholar
Gregg, S.J., Sing, K.S.W. (1982). Adsorption, surface area and porosity. Academic Press, New York, p. 303.Search in Google Scholar
Hailwood, A.J., Horrobin, S., 1946. Adsorption of water by polymers. Tran. Faraday Soc. 42B, 84–92. https://doi.org/10.1039/tf946420b084.Search in Google Scholar
Hill, C.A.S, Norton, A.J., and Newman, G. (2010). The water vapor sorption properties of Sitka spruce determined using a dynamic vapor sorption appa9ratus. Wood Sci. Technol. 44: 497–514, https://doi.org/10.1007/s00226-010-0305-y.Search in Google Scholar
Hill, C.A.S., Keating, B.A., Jalaludin, Z., and Mahrdt, E. (2012). A rheological description of the water vapour sorption kinetics behavior of wood invoking a model using a canonical assembly of Kelvin-Voigt elements and a possible link with sorption hysteresis. Holzforchung 66: 35–47, https://doi.org/10.1515/hf.2011.115.Search in Google Scholar
Hillis, W.E. (1984). High temperature and chemical effects on wood stability. Wood Sci. Technol. 18: 281–293, https://doi.org/10.1007/bf00353364.Search in Google Scholar
Ishikawa, A., Kuroda, N., and Kato, A. (2004). In situ measurement of wood moisture content in high-temperature steam. J. Wood Sci. 50: 7–14, https://doi.org/10.1007/s10086-003-0521-2.Search in Google Scholar
Keating, B.A., Hill, C.A., Sun, D., English, R., Davies, P., and McCue, C. (2013). The water vapor sorption behavior of a galactomannan cellulose nanocomposite film analyzed using parallel exponential kinetics and the Kelvin–Voigt viscoelastic model. J. Appl. Polym. Sci. 129: 2352–2359, https://doi.org/10.1002/app.39132.Search in Google Scholar
Kelsey, K.E. (1957). The sorption of water vapour by wood. Aust. J. Appl. Sci. 8: 42–54.Search in Google Scholar
Lenth, C.A. and Kamke, F.A. (2001). Equilibrium moisture content of wood in high-temperature pressurized environments. Wood fiber Sci. 33: 104–118.Search in Google Scholar
Leuk, P., Schneeberger, M., Hirn, U., and Bauer, W. (2016). Heat of sorption: a comparison between isotherm models and calorimeter measurements of wood pulp. Dry. Technol. 34: 563–573, https://doi.org/10.1080/07373937.2015.1062391.Search in Google Scholar
McDonald, J.H. (2014). Handbook of biological statistics, 3rd ed. Sparky House Publishing, Baltimore, p. 299.Search in Google Scholar
Miki, T., Sugimoto, H., Kojiro, K., Furuta, Y., and Kanayama, K. (2012). Thermal behaviors and transitions of wood detected by temperature-modulated differential scanning calorimetry. J. Wood Sci. 58: 300–308, https://doi.org/10.1007/s10086-012-1259-5.Search in Google Scholar
Obataya, E., Sakae, S., Kensuke, H., and Shuichi, D. (2006). Effects of high temperature kiln drying on the practical performances of Japanese cedar wood (Cryptomeria japonica) I: changes in hygroscopicity due to heating. J. Wood Sci. 52: 33–38, https://doi.org/10.1007/s10086-005-0716-9.Search in Google Scholar
Olsson, A.M. and Salmén, L. (1997). The effect of lignin composition on the viscoelastic properties of wood. Nord. Pulp Pap. Res. J. 12: 140–144, https://doi.org/10.3183/npprj-1997-12-03-p140-144.Search in Google Scholar
Östberg, G., Salmén, L., and Terlecki, J. (1990). Softening temperature of moist wood measured by differential scanning calorimetry. Holzforschung 44: 223–225, https://doi.org/10.1515/hfsg.1990.44.3.223.Search in Google Scholar
Pearson, H., Gabbitas, B., and Ormarsson, S. (2013). Equilibrium moisture content of radiata pine at elevated temperature and pressure reveals measurement challenges. J. Mater. Sci. 48: 332–341, https://doi.org/10.1007/s10853-012-6750-2.Search in Google Scholar
Resch, H., Hoag, M.L., Rosen, H.N., 1988. Desorption of yellow-poplar in superheated steam. F. P. J. 38, 13–18.Search in Google Scholar
Salmén, L. and Larsson, P.A. (2018). On the origin of sorption hysteresis in cellulosic materials. Carbohyd. Polym. 182: 15–20, https://doi.org/10.1016/j.carbpol.2017.11.005.Search in Google Scholar PubMed
Shi, J. and Avramidis, S. (2017a). Water sorption hysteresis in wood: I review and experimental patterns–geometric characteristics of scanning curves, Holzforschung 71: 307–316, https://doi.org/10.1515/hf-2016-0120.Search in Google Scholar
Shi, J. and Avramidis, S. (2017b). Water sorption hysteresis in wood: II mathematical modeling–functions beyond data fitting. Holzforschung 71: 317–326, https://doi.org/10.1515/hf-2016-0121.Search in Google Scholar
Shi, J. and Avramidis, S. (2017c). Water sorption hysteresis in wood: III physical modeling by molecular simulation, Holzforschung 71: 733–741, https://doi.org/10.1515/hf-2016-231.Search in Google Scholar
Shi, J. and Avramidis, S. (2019). Evolution of wood cell wall nanopore size distribution in the hygroscopic range. Holzforschung 73: 899–910, https://doi.org/10.1515/hf-2018-0198.Search in Google Scholar
Spalt, H.A., 1958. The fundamentals of water vapor sorption by wood. F. P. J. 8, 288–295.Search in Google Scholar
Strickler, M.D., 1968. High temperature moisture relations of grand fir. F. P. J. 18, 69–75.Search in Google Scholar
Weichert, L., 1963. Studies on the sorption and swelling of spruce, beech and compressed beech wood at temperatures between 20° and 100 °C. Eur. J. Wood Prod. 21, 290–300.10.1007/BF02610962Search in Google Scholar
Willems, W. (2014). The water vapor sorption mechanism and its hysteresis in wood: the water/void mixture postulate. Wood Sci. Technol. 48: 499–518, https://doi.org/10.1007/s00226-014-0617-4.Search in Google Scholar
Supplementary Material
The online version of this article offers supplementary material (https://doi.org/10.1515/hf-2019-0228).
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