Thermodynamic characterisation of particleboard using sorption isotherms

The sorption and desorption isotherms of standard particleboard were obtained in this study using the equilibrium moisture contents achieved by applying the gravimetric method of saturated salts at 35 degrees C and 50 degrees C in the water activity range of 0.11 to 0.89. The curves were fitted following the Guggenheim, Anderson and Boer-Dent model, and the isosteric heat of sorption was obtained by means of the Clausius-Clapeyron integration method. The results show that although particleboard has a thermodynamic behaviour which is qualitatively similar to solid wood, its hygroscopic behaviour is nonetheless different, as the monolayer becomes saturated by chemisorption before physisorption starts to prevail over chemisorption.