Preparation method of nanocellulose

Abstract

The present invention relates to a preparation method of nanocellulose. The preparation method is characterized by comprising the following steps: (1) mechanical crushing: grinding raw material reed pulp to be at 60-80 meshes using a refiner; (2) hydrolyzing the reed pulp through cellulase enzyme under the effect of mechanical stirring; (3) adding cellulase enzyme at an amount of NaClO solution to react for 15-20 h, and then adding HCl to stop the reaction; (4) conducting ultrasonic treatment for 30-40 min to disperse samples, centrifugally washing the samples for more than 3 times until milky colloid appears in the solution; (5) placing the colloid in a dialysis bag for more than 5 days to obtain nanocellulose colloid, freezing and drying the nanocellulose colloid in vacuum for 20-25h to obtain powder nanocellulose with above 80% crystallinity. According to the preparation method, the nanocellulose with small particle size and good dispersity is prepared by combining enzyme hydrolysis and alkali hydrolysis, and the purity of the nanocellulose prepared by the method can reach above 95%.

Description

technical field [0001] The invention relates to the technical field of nanocellulose, in particular to a preparation method of nanocellulose. Background technique [0002] Cellulose is a biodegradable polymer synthesized by plants through photosynthesis. The annual output of cellulose synthesized by photosynthesis in nature can reach tens of billions of tons, mainly from wood, cotton, grass and other plants. With the consumption of petroleum and other fossil resources and the increasingly severe environmental situation, the research on cellulose, a renewable resource, has attracted more and more attention. Due to the rapid development of nanotechnology in recent years, the research on nanocellulose has become more and more in-depth. Nanocellulose isolated from natural cellulose has many excellent properties, such as high crystallinity, high hydrophilicity, high strength, ultrafine structure, etc. [0003] As a renewable biomaterial, nanocellulose has become a research hot...

AI Technical Summary

Problems solved by technology

The traditional nanofiber preparation method has many problems. The chemical method needs to be hydrolyzed with strong acid, which requires high reaction equipment, and it is difficult to recover and treat the residue after the reaction. The biological method to prepare bacterial cellulose is complex, time-consuming, high cost, and expensive. The preparation of nanocellulose requires special equipment and high pressure, and the energy consumption is relatively high. The particle size distribution of the prepared nanocellulose is wide, the molecular weight of the artificially synthesized cellulose is small, and the microfiber prepared by electrospinning has a large cross-section and a cross-section distribution. also very wide