Sorption and thermodynamic properties of Terminalia superba Engl. &amp; Diels and Triplochiton scleroxylon K. Schum. through the 15, 35 and 50 °C sorption isotherms

Fernández, Francisco García; Esteban, Luis García; Palacios, Paloma de; Simón, Cristina; García-Iruela, Alberto; Fuente, Javier de la

doi:10.1007/s00107-013-0752-x

Cited by 27 publications

(44 citation statements)

References 15 publications

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“…These results concur with the observations of other authors for other species of wood (Themelin et al 1997;Fernandez et al 2014). The values are always positive because of the strong exothermic interaction between the water vapour and the sorption sites (Singh and Singh 1996;Kouhila et al 2002;Quirijns et al 2005a, b).…”

Section: Resultssupporting

confidence: 94%

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Juvenile and mature wood of Abies pinsapo Boissier: sorption and thermodynamic properties

et al. 2015

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For industrial processes, it is important to study the hygroscopicity and thermodynamic properties of juvenile and mature wood. Samples of Abies pinsapo Boiss. collected in the natural areas of the species in Spain were used to study these properties in both types of wood. The equilibrium moisture contents were obtained, and the 15, 35 and 50°C isotherms were plotted following the Guggenheim-Anderson-Boer-Dent model. The thermodynamic parameters were calculated using the integration method of the Clausius-Clapeyron equation. Chemical analyses, infrared spectra and X-ray diffractograms were applied to assess chemical modifications and possible changes in the cell wall structure. The chemical composition of the mature wood shows a decrease in the lignin and hemicelluloses content and an increase in the extracts and a-cellulose. The sorption isotherms for the three temperatures studied are higher in the mature wood than in the juvenile wood. Causes of this include the higher content of a-cellulose, the higher crystallinity index and the shorter crystallite length in the mature wood. No difference was found between the juvenile and mature wood in relation to the point of inflexion where the multilayer starts to predominate over the monolayer (approximately 30 %). In terms of the thermodynamic properties, the heat involved is greater in desorption than in adsorption, and more heat is involved in the mature wood than in the juvenile wood.

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Section: Resultssupporting

confidence: 94%

“…Similarly, there is no relation between the K constant and temperature, as found in other studies (Themelin et al 1997;Esteban et al 2008a, b;Lequin et al 2010;Fernandez et al 2014). K cannot take values greater than one because sorption becomes infinite with water activity values lower than 1 (Chirife et al 1992; Maskan and Gogus 1997).…”

Section: Resultsmentioning

confidence: 65%

Juvenile and mature wood of Abies pinsapo Boissier: sorption and thermodynamic properties

et al. 2015

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“…The GAB model constants do not follow a distribution with the temperature (Table 2), concurring with findings for other types of wood [14,28,55]. The C g value is positive due to the strong exothermic interaction between the water molecules and the sorption sites [56][57][58].…”

Section: Discussionsupporting

confidence: 86%

“…3) has been reported in other species of wood [14,47,55] and other hygroscopic materials of plant origin [75]. The maximum isosteric heat at low EMC values indicates that the interactions between the water molecules and the substratum are very strong [76], due to the existence of highly polar sites on the surface of the material occupied by the water molecules forming a monolayer [77].…”

Section: Discussionmentioning

confidence: 87%

Thermodynamic analysis of water vapour sorption behaviour of juvenile and mature wood of Abies alba Mill.

et al. 2015

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The hygroscopicity and thermodynamic properties of juvenile and mature wood of Abies alba Mill. were studied through the 15, 35 and 50°C sorption isotherms. The Guggenheim, Anderson and de Boer-Dent model was used to fit the isotherms. The thermodynamic parameters were obtained from the sorption isotherms by applying the integration method of the Clausius-Clapeyron equation. The chemical composition of both types of wood (extractives, lignin and carbohydrate polymer-cellulose and hemicellulose-content) was determined, and infrared spectroscopy and X-ray diffractograms were used to identify any chemical modifications and changes in the crystal structure of the cell wall. The mature wood has more cellulose and hemicellulose content and less extractives content than the juvenile wood. The shorter crystallite length in the mature wood creates a higher amount of amorphous zones and, as a consequence, a higher number of access areas to the -OH groups. The combination of these phenomena explains the different hygroscopic behaviour between the juvenile and the mature wood, as the latter has higher moisture content in the three isotherms. As regards the thermodynamic properties, the amount of energy involved in the sorption process is greater in the mature wood than in the juvenile wood.

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“…The time-dependent mechanical response of wood is affected by these changes and known as hygromechanical behavior. Although many studies have been conducted on the hygromechanical properties of wood from tropical regions, particularly those of Africa-such as African whitewood, frake and grenadilla's twin wood species in appearance, ebony (Jannot et al 2006;Fernández et al 2014;Simo-Tagne et al 2016a, 2019-few have determined such properties for grenadilla.…”

Section: Introductionmentioning

confidence: 99%

Hygromechanical properties of grenadilla wood (Dalbergia melanoxylon)

et al. 2020

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Grenadilla wood (Dalbergia melanoxylon Guill. & Perr.) is a hardwood species found in Tanzania, Mozambique, and other countries in the tropical part of Africa, especially in the Eastern-Central region. Thanks to its high density and good hygroscopic stability, it is used in the making of various musical instruments and fine furniture. Due to the scarcity of published data on this wood species, more studies on its properties are needed to improve its processing and use, and even to search for sustainable alternative materials as its trade is increasingly limited by new regulations. This work is focused on the hygromechanical properties, which hold an important role in the applications of this wood: diffusion coefficients and adsorption-desorption curve (both measured at T = 20 • C), swelling-shrinkage coefficients and full orthotropic elastic constants using an ultrasonic method. Results show that grenadilla wood possesses small water diffusion coefficients (from 1.54 ± 0.49 × 10 −7 cm 2 ∕s in T direction to 4.58 ± 0.84 × 10 −7 cm 2 ∕s in L direction), which is probably related to its high density (1250.0 ± 26.2 kg∕m 2 ); unique equilibrium moisture content (sorption) curve with a lower fiber saturation point (0.173 ± 0.003); smaller swellingshrinkage coefficients (0.20 ± 0.03 and 0.32 ± 0.05 in T and R directions, respectively); and elastic constants lower in the longitudinal direction (15.56 ± 1.79 GPa) and higher in the transverse ones (5.10 ± 0.46 GPa and 4.05 ± 0.35 GPa in R and T directions, respectively) than what could be expected with a standard model based on the density only. Several explanations were described here, from the effects of a high extractive content to the possibility of a high microfibril and/or fiber angle.

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Sorption and thermodynamic properties of Terminalia superba Engl. & Diels and Triplochiton scleroxylon K. Schum. through the 15, 35 and 50 °C sorption isotherms

Cited by 27 publications

References 15 publications

Juvenile and mature wood of Abies pinsapo Boissier: sorption and thermodynamic properties

Juvenile and mature wood of Abies pinsapo Boissier: sorption and thermodynamic properties

Thermodynamic analysis of water vapour sorption behaviour of juvenile and mature wood of Abies alba Mill.

Hygromechanical properties of grenadilla wood (Dalbergia melanoxylon)

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