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Method for synchronously preparing cellulose nanowhiskers and cellulose nanofibrils

A technology of nano-whiskers and nano-fibrils, which is applied in the post-treatment of cellulose pulp, the post-treatment modification of cellulose pulp, and the treatment of fiber raw materials. The time consumed, the initial temperature is high, and the effect of realizing full utilization

Inactive Publication Date: 2020-07-10
SOUTH CHINA UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The high-pressure homogenization method has the disadvantage of high energy consumption, and the TEMPO oxidation method has the disadvantages of complicated methods.
At the same time, the fiber conversion rate of the above method is low, which virtually causes waste of raw materials
In order to solve this problem, some scholars homogenized the residue left by the hydrolysis of concentrated sulfuric acid to obtain cellulose nanofibrils. High-yield cellulose nanofibrils were obtained by high-pressure homogenization, but cellulose nanowhiskers were not obtained, and the reducing sugar in the hydrolyzate was not comprehensively utilized
Patent CN106883301B simultaneously prepared cellulose nanocrystals and cellulose nanofibrils by wet grinding. Although this method has a high conversion rate, it has problems such as high energy consumption and poor product dispersibility.
Therefore, it is necessary to solve the complex process and follow-up treatment of waste acid in the traditional method of preparing nanocellulose, and to simultaneously obtain cellulose nanowhiskers and cellulose nanofibrils to realize the full utilization of raw materials.

Method used

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  • Method for synchronously preparing cellulose nanowhiskers and cellulose nanofibrils
  • Method for synchronously preparing cellulose nanowhiskers and cellulose nanofibrils
  • Method for synchronously preparing cellulose nanowhiskers and cellulose nanofibrils

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Effect test

Embodiment 1

[0034] Sulfuric acid concentration is 0.3wt%, namely sulfuric acid: water=mass ratio 0.3%;

[0035] Fiber concentration is 3wt%, namely fiber: water+fiber=mass ratio 3%;

[0036] After mixing 1.5g of plant fiber slurry with 48.5mL of sulfuric acid solution, react at 160°C for 2 hours through a hydrothermal reactor, and start timing when the temperature is stable; After centrifugation at 10000rpm for 15min, the suspension of cellulose nano whiskers was obtained, and its morphology was characterized by scanning electron microscopy, as figure 2 As shown, the cellulose nano-whiskers are in a rod-like structure, and the length is mainly distributed between 200-400nm; through the size statistics of the suspension obtained under the conditions of Example 1 by the software Nano Measurer 1.2, the cellulose nano-whiskers are long for 150-400nm. 500nm, about 15-35nm in diameter (see image 3 ); the remaining cellulose solid residue was subjected to high-pressure homogenization for 6 t...

Embodiment 2

[0038] Sulfuric acid concentration is 0.3wt%, namely sulfuric acid: water=mass ratio 0.3%;

[0039] Fiber concentration is 4wt%, namely fiber: water+fiber=mass ratio 4%;

[0040] After mixing 2g of plant fiber slurry with 48mL of sulfuric acid solution, react at 160°C for 2 hours through a hydrothermal reactor, and start timing when the temperature is stable; After centrifugation for 15 minutes, the cellulose nano whisker suspension was obtained; the remaining cellulose solid residue was homogenized by high pressure for 6 times to obtain nanocellulose fibrils, such as Figure 4 As shown, the length is about 400nm-1200nm, and the yield is about 68.67%.

Embodiment 3

[0042] Sulfuric acid concentration is 0.35wt%, namely sulfuric acid: water=mass ratio 0.35%;

[0043] Fiber concentration is 4wt%, namely fiber: water+fiber=mass ratio 4%;

[0044] After mixing 2g of plant fiber slurry with 48mL of sulfuric acid solution, react at 150°C for 3 hours through a hydrothermal reactor, and start timing when the temperature is stable; After centrifugation for 15 minutes, a cellulose nanowhisker suspension was obtained; the remaining cellulose solid residue was homogenized by high pressure for 6 times to obtain nanocellulose fibrils, and the yield was about 67.42%.

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Abstract

The invention discloses a method for synchronously preparing cellulose nanowhiskers and cellulose nanofibrils. The method comprises the following steps: carrying out hydrolysis reaction on paper pulpby using a low-concentration sulfuric acid solution at high temperature to obtain cellulose nano whisker turbid liquid, and homogenizing separated cellulose solid residues by using a high-pressure homogenizer to obtain the cellulose nano fibrils. According to the preparation method, fiber raw materials can be fully utilized, the conversion rate is close to 100%, the prepared nano cellulose has a high length-diameter ratio, the initial thermal degradation temperature of the nano cellulose is about 100 DEG C higher than that of nano cellulose prepared through a traditional concentrated sulfuricacid method, and the method has great advantages in the aspect of application of nano composite materials.

Description

technical field [0001] The invention belongs to the field of cellulose materials, in particular to a method for synchronously preparing cellulose nano whiskers and cellulose nano fibrils. Background technique [0002] Cellulose is the most potential renewable biomass material on the earth, and it is widely used in papermaking, daily chemicals, textiles and other fields. Nanocellulose has attracted much attention due to its excellent properties (high crystallinity, low density, large specific surface area, high strength, etc.). Many high-value by-products can be derived from nanocellulose as bio-based materials, such as hydrogels, aerogels, nanocomposites, optical and electronic materials, etc. [0003] At present, there are many methods for preparing nanocellulose, such as concentrated sulfuric acid method, high-pressure homogenization method, TEMPO oxidation method, etc., but the above methods have certain shortcomings, such as patent CN105625077A using concentrated sulfur...

Claims

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Application Information

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IPC IPC(8): D21H11/18D21H11/20D21C9/00
CPCD21C9/004D21H11/18D21H11/20
Inventor 徐峻王佳佳王斌高文花李军曾劲松陈克复
Owner SOUTH CHINA UNIV OF TECH
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