Properties of Medium-Density Fiberboards from Bagasse Digested with Different Retention Times

The present work deals with studying the influence of different steam digestion retention times on properties of finished medium-density fiberboard (MDF). It aims to operate the defibration process with the minimum deterioration of stored bagasse-fiber strength. In this respect the wet-stored bagasse (WSB) samples were studied, parallel to dry-stored bagasse (DSB) samples, at different digestion retention times. Regression equations of quadratic order were used to optimize the independent variables (retention time and storage period). The results obtained show that a relatively higher digestion time (353 s) reduced the hollocellulose and hemicellulose contents of WSB. In the case of DSB, the changes in chemical constituents as a function of retention time were not very significant because the mechanical properties of MDF (static bending, internal bond, and screw holding) produced from applying a higher digestion time do not fulfill the standard requirements of ANSI A208.2. However, digestion at a shorter retention time (253 s) is recommended for stored bagasse in order to produce a board that complies with the European standards on MDF. DSB fibers at all the examined retention times are recommended for comparison. The advantage of applying a shorter retention time is evident from preserving, to some extent, the chemical constituents of WSB fibers.