Thermo-mechano-chemical deconstruction of cellulose for cellulose nanocrystal production by reactive processing
Karelle S Guiao1, Costas Tzoganakis1, Tizazu H Mekonnen1
1Department of Chemical Engineering, Institute of Polymer Research, Waterloo Institute of Nanotechnology, University of Waterloo, Waterloo, Ontario, Canada.
Abstract:
The commercial production of cellulose nanocrystals (CNCs) requires high concentration of sulfuric or other acids such as hydrochloric, phosphoric, and nitric acids. However, these acids and the involved process are corrosive, toxic, energy-intensive, and not environmentally safe. In this work, a batch mixer reactive process that entails high shear was implemented using 1-butyl-3-methylimidazolium chloride (BmimCl) media and molten oxalic acid dihydrate (OA) to produce CNCs from cellulose. Through this, a maximum CNC yield (59 wt%) was obtained with a mixture composition of 1:0.7:0.075 (Cellulose:BmimCl:OA, w/w/w) and a processing time of 2.5 min. Further investigation revealed that the particle size, degree of crystallinity, and thermal stability of the produced CNCs were found to be competitive with those of a commercial CNC product. This study asserts the potential industrial application of an efficient ionic liquid and molten organic acid treatment for CNC production via reactive processing in a batch mixer.
