Method for preparing cellulose nanofibril CNF through polyatomic acid treatment

Abstract

The invention discloses a method for preparing cellulose nanofibrils (CNF) by adopting polyatomic acid high-temperature short-time treatment, and belongs to the field of natural polymer materials. Inthe preparation process of CNF, chemical pulp is used as a raw material, cellulose is decomposed at high temperature for a short time by adopting binary or ternary organic acid, the Zeta potential ofthe cellulose is reduced, and the Zeta potential of the cellulose is further reduced through carrying out oxidation treatment on the pulp subjected to acidolysis; and finally, the oxidized slurry is subjected to high-pressure homogenization treatment, the CNF colloid with high dispersity is obtained, and the Zeta potential of the CNF colloid can reach -40 mV or above. The preparation process has good industrial implementation conditions, and the prepared CNF has the characteristics of high yield (more than 90%), good dispersibility, stable performance, large length-diameter ratio and the like,and has a good application prospect.

Description

technical field [0001] The invention provides a method for preparing CNF by polybasic acid treatment, which has properties such as high yield and good dispersibility. Background technique [0002] Cellulose nanofibrils (CNF) refer to microfibril bundles (clusters) with diameters of nanometers and lengths of hundreds of nanometers or even micrometers. There are both crystalline regions and amorphous regions in the CNF structure, which has the advantages of high hydrophilicity, renewable, easy biodegradation, high reactivity, nano-size effect, etc., and is widely used in food, medicine, automobiles, composite materials, electronic products and oil exploration and other fields. [0003] At present, there are more than ten methods for preparing CNF, among which the most commonly used methods include high-pressure homogenization, microfluidics, and grinding. The energy consumption of CNF prepared by purely mechanical method is high, and the energy consumption of its preparation...

AI Technical Summary

Problems solved by technology

The energy consumption of CNF prepared by purely mechanical method is high, and the energy consumption of its preparation is as high as 70MWh / t, which leads to high production cost, and at the same time, there are equipment blockage, low efficiency of spinning broom, serious damage to cellulose structure, and uneven particle size of CNF , poor dispersion and other issues

In response to the above problems, many researchers have developed a series of pretreatment methods, including enzymatic hydrolysis, sulfuric acid hydrolysis, carboxymethylation, TEMPO catalytic oxidation, periodate oxidation, etc. At present, the above pretreatment methods have some shortcomings , such as expensive chemicals used, long preparation reaction time, serious environmental pollution, poor product dispersion, etc., severely limit the industrial production and application of CNF