Precisely controlled preparation of uniform nanocrystalline cellulose via microfluidic technology

As a new type of biomass-based molecular material, nanocrystalline cellulose (NCC) has become a research hotspot in many fields. In present work, a novel microfluidic technology was employed to produce NCC from microcrystalline cellulose (MCC) via sulfuric acid hydrolysis. The microfluidic chip was designed and made with complete load-bearing reaction according to flow characteristics. A closed reaction environment and fully automated operations can ensure the safety of experimenters. NCC (MN-60) with high yield and uniformity was obtained via acid hydrolysis in microfluidic system by 60 % sulfuric acid solution at 35 °C for 40 min. The characteristics of MN-60 and conventional method NCC (N-60) under the same reaction conditions were compared. It was found that the yield of MN-60 reached 48.13%, while it was only 17.30 % in the absence of microfluidic chip. Although the results showed that MN-60 and N-60 exhibited similar rod-like structures, the size distribution of MN-60 was narrower than that of N-60. Furthermore, the width, length, and height of MN-60 were 15 ± 5 nm, 150 ± 75 nm, and 5 ± 2 nm, respectively. The main functional groups and crystal forms of MN-60 were similar to MCC, but the crystallization index of MN-60 was higher than MCC. In conclusion, microfluidic technology could realize the preparation of high-yield and uniform NCC. © 2021