(137a) Towards Economical and Sustainable Production of Wood Based Nanomaterials

Authors: 
Zhu, J. Y., USDA Forest Service
In this presentation, I will outline the current status of cellulose nanomaterial production including the deficiencies of existing technologies. Then, I would like to discuss some of our research on integrated production of cellulose nanocrystals (CNC) and fibrils (CNF) with full recovery of chemicals. Specifically I will present our recent study using dicarboxylic acids (DCAs) for sustainable and potentially economical production of highly thermal stable and functional (carboxylated) cellulose nanomaterials. DCA hydrolysis overcomes several disadvantages of existing technologies (mineral acid or enzymatic hydrolysis, oxidation such as TEMPO-mediated), such as (1) low thermal stability which prevented their applications in the largest market – wood based composites processed at elevated temperatures such as extrusion; (2) difficulties in economic recovery of chemicals. DCAs can be easily and economically recovered through commercially proven crystallization process at ambient temperatures. DCA hydrolysis (DCAH) resulted in low CNC yield, but minimal cellulose loss or high solids yield. The remaining partially hydrolyzed fibers can be subsequently fibrillated into CNF to realize integrated production of CNC with CNF with tunable yield, properties, and morphologies. The DCAH-CNC has carboxylic acid group content of 0.1 – 1.5 mmol/g CNC. The DCAH-CNF was also functionalized with surface carboxyl groups for dispersion. The low strength of DCA also resulted in CNC with higher crystallinity and longer lengths of 300 – 600 nm than those produced using mineral acids, suitable for polymer reinforcement.