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

Abstract

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.

Sorption and thermodynamic properties of wood of Pinus canariensis C. Sm. ex DC. buried in volcanic ash during eruption

“…In this study, the EMC values of the mature wood are higher than those of the juvenile wood for each temperature (Fig. 1), concurring with Zobel et al (1968), Militz et al (2003), Neimsuwan et al (2008), Esteban et al (2015) and Simon et al (2015). The differences between the EMC values obtained can be explained by the chemical composition of the cell wall.…”

“…The first comparison indicates a relation between growth ring location and hygroscopic behaviour. This was corroborated by authors who studied different species, both softwoods and hardwoods (Zobel et al 1968;Lenth and Kamke 2001;Militz et al 2003;Majka and Olek 2008;Neimsuwan et al 2008;Esteban et al 2015;Simon et al 2015). In this study, the EMC values of the mature wood are higher than those of the juvenile wood for each temperature (Fig.…”

“…As a result, the cellulose and hemicellulose contents are higher in the mature wood than in the buried wood (8.63 and 4.16%, respectively) and in the juvenile wood (2.44 and 1.22%). The higher cellulose content in the mature wood than in the juvenile wood agrees with the findings of earlier studies (Larson 1966;Fengel and Wegener 1983;Tsoumis 1991;Yokoyama et al 2002;Illic et al 2003;Bertaud and Holmbom 2004;Balakshin et al 2005;Rowell 2005;Peura et al 2008;Simon et al 2015). In addition, Iiyama et al (1988) studied the behaviour of the chemical compounds in old woods that had been buried and concluded that the sugar content decreased considerably.…”

Thermochemical and Mechanical Properties of Pine Wood Treated by In Situ Polymerization of Methyl Methacrylate (MMA)

“…This proves that the JV and MT present different amounts of primary compounds (c.a. cellulose, hemicellulose and lignin) [14,32].…”

Sorption Isotherms and Isosteric Heat of Pericarp and Endosperm Tissues of Arabica Coffee Fruit

“…Several models had been utilized for representing sorption isotherms, and, although very well adapted to the obtained data, they typically have thermodynamic errors. However, the model development always comprises some simplification of the sorption process (Simón et al, 2015).…”