PREPARATION AND CHARACTERIZATION OF CELLULOSE NANOCRYSTALS FROM WOOD-BASED PANELS

摘要

Every year,a huge amount of wood-based panels complete their service life and need to be discarded.How to recycle and reuse these adhesive-containing panels has been attracted great interest worldwide.In this work,cellulose fibers were isolated from medium density fiberboards by a three-step dewaxing-sodium chlorite oxidation-alkaline leaching process at a yield of 37.7％.Most of the urea-formaldehyde residue in the fiberboard was hydrolyzed and removed by the alkaline treatment step.The value-added cellulose nanocrystals(CNCs)with 10-20 nm wide and 2-3 micros long were isolated from the fibers at the highest yield of 27.5％via sulfuric acid hydrolysis.The optimized hydrolysis condition was acid concentration of 65 wt％,reaction time of 30 min and temperature of 60 ℃.The CNCs obtained were negatively charged(0.44 mmol/g)and highly crystalline(61％).