Method for preparing nanoscale regenerated cellulose by adopting molten salt system

A regenerated cellulose, nano-scale technology, applied in the direction of single-component cellulose rayon, fiber chemical characteristics, bulk chemical production, etc., can solve problems such as strict moisture content requirements, restricting industrialization promotion, polluting environmental energy consumption, etc.

Active Publication Date: 2020-10-20
QINGDAO INST OF BIOENERGY & BIOPROCESS TECH CHINESE ACADEMY OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] Generally speaking, the current research on the preparation of nanocellulose focuses on cellulose type I, which mainly has the following problems: difficult recovery of chemical reagents, expensive chemicals, long reaction time, environmental pollution and high energy consumption
This method mainly produces nanocellulose by breaking the hydrogen bonds between cellulose molecules; although the solubility of ionic liquids is high, the cost is high, and the water content is strictly required during its use, which restricts its industrialization.

Method used

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  • Method for preparing nanoscale regenerated cellulose by adopting molten salt system
  • Method for preparing nanoscale regenerated cellulose by adopting molten salt system
  • Method for preparing nanoscale regenerated cellulose by adopting molten salt system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] 100 g of molten salt system containing 54% (w / w) LiCl was accurately prepared with pure water. Accurately weigh 1g of microcrystalline cellulose powder, with a solid-to-liquid ratio of 1:100, and add it to the LiCl molten salt system; raise the temperature to 95°C, and continue stirring at 600rpm for 8 hours to completely dissolve the cellulose to obtain a uniform cellulose-molten saline solution. Then the cellulose-molten salt solution was poured into 200 g of water, and filtered to obtain regenerated cellulose. Then redisperse the separated regenerated cellulose in 250g of pure water to form a regenerated cellulose dispersion; homogenize 20 times with a high-pressure homogenizer at 60MPa to obtain a colloidal cellulose nanocrystal dispersion system.

[0037] The yield of cellulose nanocrystals obtained in this embodiment is 98.2% (relative to the original absolute dry microcrystalline cellulose), and the crystal structure of the prepared cellulose nanocrystals is sig...

Embodiment 2

[0039] Accurately prepare 100g of pure water containing 25% (w / w) ZnCl 2 molten salt system. Accurately weigh 2g of dry bleached softwood pulp, with a solid-to-liquid ratio of 1:50, and add it to the ZnCl molten salt system; raise the temperature to 105°C, and continue stirring at 300rpm for 2 hours to completely dissolve the cellulose to obtain a uniform cellulose- molten salt solution. Then pour the cellulose-molten salt solution into 1000 g of pure water, and centrifuge to obtain regenerated cellulose. Then redisperse the separated regenerated cellulose in 300g of pure water to form a regenerated cellulose dispersion; then homogenize for 15 times with a high-pressure homogenizer at 60 MPa to obtain cellulose nanocrystals.

[0040] The yield of the cellulose nanocrystals prepared in this example was 97.4% (relative to the original dry bleached softwood pulp). Cellulose nanocrystals with uniform particle size are prepared. According to the TEM pictures and software statist...

Embodiment 3

[0042] Accurately prepare 100g of 85% (w / w) LiClO with pure water 4 molten salt system. Accurately weigh 12.5g of dry bleached hardwood pulp, and add it to LiClO with a solid-to-liquid ratio of 1:8 4 In the molten salt system, the temperature was raised to 115° C., and the cellulose was completely dissolved after stirring at 400 rpm for 0.5 hour to obtain a uniform cellulose-molten salt solution. Then the cellulose-molten salt solution was poured into 1500g of pure water to obtain flocculent regenerated cellulose immediately. Then filter, and redisperse the separated regenerated cellulose in 400 g of absolute ethanol to form a regenerated cellulose suspension; then homogenize for 15 times with a high-pressure homogenizer at 100 MPa to obtain cellulose nanospheres.

[0043] The yield of the cellulose nanospheres prepared in this example was 99.0% (relative to the original dry bleached hardwood pulp). Cellulose nanospheres with uniform particle size were prepared, and the dia...

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Abstract

The invention discloses a method for preparing nanoscale regenerated cellulose by adopting a molten salt system. The method specifically comprises the following steps: (1) adding a cellulose raw material into a molten salt system, and heating and dissolving to obtain a uniform and transparent cellulose-molten salt solution; (2) adding a proper amount of regeneration solvent into the cellulose-molten salt solution, and carrying out solid-liquid separation to obtain nanoscale regenerated cellulose; (3) washing the separated regenerated cellulose solid with water, and evaporating and concentrating the separated liquid to recover the regeneration solvent and obtain a regenerated molten salt solution; and (4) preparing the cleaned regenerated cellulose into a cellulose dispersion liquid, and carrying out high-pressure homogenization treatment to obtain the stably dispersed nanoscale regenerated cellulose. According to the invention, the yield of the nanoscale regenerated cellulose preparedby the method is 96-99%, the cost is low, the process is green, clean and sustainable, nano-crystalline cellulose materials in different aggregation states can be obtained, and the method has an important promotion effect on the development of the nano-crystalline cellulose industrial process.

Description

technical field [0001] The invention belongs to the field of materials, relates to the field of preparation of natural polymer materials, in particular to a method for preparing nanoscale regenerated cellulose by adopting a molten salt system. Background technique [0002] In recent years, people have paid more and more attention to resource and environmental issues, and it has become an inevitable trend to develop and utilize renewable resources to replace traditional fossil resources. Cellulose is the most abundant biopolymer on earth and mainly exists in the cell walls of higher plants; therefore, it has the advantages of wide source of raw materials, non-toxic, renewable and degradable. As a nanoscale material, nanocellulose has the advantages of high specific surface area, high aspect ratio, and low density, as well as high Young's modulus, high tensile strength, high crystallinity, and low thermal expansion coefficient. Wait. Based on the above characteristics, nanoc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J3/03C08L1/04C08B15/02D01F2/00
CPCC08J3/03C08B15/02D01F2/00C08J2301/04Y02P20/54
Inventor 李滨黄仲雷刘超吴美燕崔球
Owner QINGDAO INST OF BIOENERGY & BIOPROCESS TECH CHINESE ACADEMY OF SCI
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