Green Macro Preparation and Mechanism Research of NanocelluloseBased on Radiation Degradation Effect

YANG Bei， CUI Guoshi， ZHAO Hongying， SHU Xingjuan， FAN Ru

(Henan Kegao Radiation Chemical Technology Co． Ltd．，Henan Key Laboratory for Radiation Chemistry Advanced Materials， Luoyang 471000， China )*Corresponding E-mail： cuiguoshi2008@126．com

Key words: electron beam irradiation; nanocellulose; Green macro; mechanism research

Nanocellulose and its application are the hotspot research fields of cellulose science． Foreign companies such as Nippon Paper， Sweden’s Innventia， and Canada’s CelluForce have invested in pilot-scale test equipment．While most of China’s research in this area is still in the laboratory research stage． The acid hydrolysis method is one of the most widely used methods for preparing nanocellulose， but the method requires a large amount of high-concentration inorganic acid， which is difficult to process， has low preparation efficiency， and has serious environmental pollution problems． The TEMPO catalytic oxidation method is another preparation method for studying more nanocellulose． However， TEMPO catalysts are expensive and difficult to recycle， resulting in high production costs and limited application．

In this study， micron-sized cellulose fibers were first prepared by electron beam radiation and mechanochemical treatment using natural wood pulp cellulose． The micron-sized cellulose fibers were then prepared by highpressure homogenization to a high concentration(≥5．0%)． According to the analysis of atomic force microscopy(AFM) and laser particle size analyzer， the prepared nanocellulose has a diameter of 40-60 nm and a length of 100-450 nm， which is short rod-shaped． The dose of electron beam irradiation and the amount of catalyst in the mechanochemical treatment stage and the concentration and time of the material in the high pressure homogenization process have a significant effect on the size and aspect ratio of the nanocellulose． The preparation mechanism can be described as ‘three-step method’． Firstly， the radiation degradation process reduces the degree of polymerization of cellulose and causes a large number of defects in the cellulose crystals． Secondly， in the mechanochemical treatment process， under the action of mechanical force and trace catalyst， the fibril fibers are gradually separated， cut and peeled from the surface to the inside to form short rod-shaped micron-sized fibers．Finally， the high pressure homogenization process further separates the micron-sized fibers into short rod-shaped nanocellulose crystals．

In the preparation process of nanocellulose， only a small amount of catalyst is added， and there is no pollutant discharge; the post-treatment is simple， the industrialization is easy to implement， and the cost is low． This research is of great value for the large-scale production and widespread application of nanocellulose．