Analysis of the Wood Sorption Isotherm Using Clustering Theory

A critical discussion of the physics of wood–water interactions

“…Freezing bound water exhibits a phase change between -10 and -20°C, whereas non-freezing bound water does not freeze down to -70°C (Berthold et al 1996). Freezing bound water has therefore been assumed to be less confined by and more loosely bound to the cell wall than non-freezing bound water, for example, as water clusters in line with theoretical considerations of Hartley et al (1992) and Hartley and Avramidis (1993). However, Berthold et al (1996) only found freezing bound water in ligno-cellulosic model compounds containing weak or strong acidic groups, that is, not in native wood.…”

Fractal dimension of wood surfaces from sorption isotherms

“…(5) and (6) that at relative vapour pressures above 0.85, the surface fractal dimension as a result of the increasing slope, reaches values around 3 indicating a more complex surface (Adamson 199o). This might be the result of the polymolecular and possibly water cluster formation in high relative humidities as discussed by Hartley and Avramidis (1993). On the other hand, for relative vapour pressures below 0.25 (monolayer region), the surface becomes simpler as its fractal dimension approaches 2.…”

Prediction of vapor–moisture equilibriums for a wood–moisture system using a modified UNIQUAC model

“…Several comparative studies of sorption theories relating to the wood-moisture system have appeared in the literature (Hartley and Avramidis, 1993;Hartley et al, 1992;Simpson, 1980). These noted that many models merely provide empirical equations for correlating and interpolating data through curve fitting and ascribe this to the complexity of the polymer structure of wood.…”

“…These noted that many models merely provide empirical equations for correlating and interpolating data through curve fitting and ascribe this to the complexity of the polymer structure of wood. A popular example of a model to describe water adsorption by fibrous materials using a solution theory is that by Hailwood and Horrobin (1946), which has been mentioned and employed by several researchers (Hartley and Avramidis, 1993;Hartley et al, 1992;Peralta, 1995;Simpson, 1973Simpson, , 1980. However, this model makes the assumption that water and fibrous polymers form an ideal solid solution, which is physically inappropriate for the behavior of water adsorption in wood.…”