Abstract : In this study, modification of European beech wood (Fagus sylvatica) through in situ
esterification of sorbitol and citric acid (SorCA) was investigated at two curing
temperatures, 140 and 160 °C. In order to determine the optimum condition for
modification, an aqueous solution of SorCA at varying concentrations was evaluated
(10, 20, 30, and 55% w/w). Physical, mechanical, chemical, and durability properties
of the modified wood were examined. Results have disclosed that among different
SorCA concentrations, treatment with SorCA at 30% w/w was considered as the
optimum concentration independent of the curing temperature. Under these conditions,
anti-swelling efficiency increased to approx. 55% and modulus of elasticity
increased slightly with approx. 9% in comparison with untreated wood. Decay resistance
against white-rot (Trametes versicolor), brown-rot (Coniphora puteana), and
soft-rotting microfungi classified the SorCA-30%-modified wood as very durable. In
addition, thermogravimetric study evidenced that SorCA 30%-modified wood has a
lower thermal decomposition temperature in comparison with untreated wood/wood
control by 20 °C difference, indicating that the SorCA-modified wood possibly has
fire-retardant properties. However, due to the acidic properties of the SorCA solution,
modulus of rupture (MOR) and mainly work to maximum load in bending decreased
considerably.