【讲座题目】Towards Economical and Sustainable Wood Cell Wall Deconstruction: Part I - Producing Cellulose Nanomaterials
【讲座时间】 2017年8月25日 （周五）上午10:00
【主 讲 人】 J.Y. Zhu，USDA Forest Service, Forest Products Laboratory, Madison, WI, USA
Dr. J.Y. Zhu is a scientific team leader at the US Forest Service, Forest Products Laboratory, Madison, Wisconsin. He holds an Adjunct Appointment at the Dept. of Biological Systems Engineering, University of Wisconsin-Madison. He was the Inaugural Fulbright-Aalto University Distinguished Chair in Energy and Sustainable Use of Natural Resources (2015-2016 academic year), Helsinki, Finland.
His research covers a broad area of wood and fiber utilization from wood pulping, fiber physics, bioenergy and biofuels, to cellulose nanomaterials that encompassed from laboratory studies to commercial scale demonstrations. The SPORL process his group developed was used for the world FIRST successfully woody cellulosic bio-jet (from forest residue) commercial flight from US west coast (Seattle) to east coast (Washington DC) on November 14, 2016. Dr. Zhu’s achievements were honored with AIChE (American Institute of Chemical Engineers) Andrew Chase Award in 2016, TAPPI (Technical Association of the Pulp and Paper Industry) International R&D Technical Award and William Aiken Prize in 2014, and US Forest Service Deputy Chief for R&D Distinguished Science Award in 2013. Dr. Zhu is a Fellow of TAPPI, AIChE, and IAWS (International Academy of Wood Science).
Lignocellulose based nanomaterials such as cellulose nanocrystals (CNC) have attracted great interest recently due to renewability, biodegradability, and other unique mechanical and optical properties with a potential to produce a variety of products for a sustainable future. Economic and environmentally sustainable production, however, is the key to achieve these potentials.
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 solid 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.