Recycling of waste MDF via digester and production of nanocrystalline cellulose from recycled fibers

In this study, the fibers contained in the medium density fiberboard wastes were recycled using a digester. These fibers were then used to produce cellulose nanocrystals. Morphology, chemical structure and resin residues on fibers were investigated. The acid hydrolysis method was utilized to production cellulose nanocrystals. The properties of nanocrystals made from virgin and recycled fibers were investigated. The results showed changes in the morphology and chemical structure of the recycled fibers. The fibers recycled using digester had better quality as compared to the recycled fibers using conventional recycling method (using autoclave). Elemental analysis showed that after recycling, resin residues remained on the fibers. Due to the shorter duration of heat treatment and the elimination of mechanical separation and better quality of recycled fibers, it can be said that the utilization of digester considered as an efficient method for recycling medium density fiberboard wastes. Investigation of nanocrystalline cellulose properties showed that there was no difference between nanocellulose produced from virgin and recycled fibers and the recycled fibers can be well utilized to production of cellulose nano crystals.