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Highly-heat-resistant redispersible powder cellulose nano-crystal and preparation method thereof

A technology of cellulose and nanocrystals, which is applied in the field of powder cellulose nanocrystals preparation, can solve the problems of poor heat resistance of cellulose nanocrystals, difficulty in redispersing in the water phase, and unsuitability for industrial production, so as to save the need for dialysis Handling, improved stability, easy-to-control effects

Active Publication Date: 2017-06-30
QINGDAO UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the use of sulfuric acid to hydrolyze cellulose in this method, the prepared cellulose nanocrystal suspension contains a large amount of free sulfonate ions, and the existence of these sulfonate ions will adversely affect the heat resistance of cellulose nanocrystals, resulting in Cellulose nanocrystals begin to decompose at around 90°C, so dialysis is generally required to remove free sulfonate ions during post-treatment (ACS Sustainable Chem. Eng. 2016, 4, 2517-2527) to improve the heat resistance of cellulose nanocrystals Sex, but the dialysis process is not only time-consuming, but also consumes a lot of water, resulting in great waste
In addition, negatively charged sulfonate groups are grafted on the surface of the obtained cellulose nanocrystals, which is beneficial to its dispersion in the water phase, but the presence of such sulfonate groups also affects the heat resistance of the cellulose nanocrystals. Adverse effects (Biomacromolecules 2004,5,1671-1677), and dialysis cannot be removed, so the heat resistance of cellulose nanocrystals produced by acid hydrolysis is still poor after dialysis treatment (begins to decompose around 150°C)
[0006] There are a large number of hydroxyl groups on the surface of cellulose nanocrystals, which are easy to form strong hydrogen bonds during the drying process, resulting in the agglomeration of powder cellulose nanocrystals after water removal, and it is difficult to disperse into a stable suspension in water during subsequent use, so Dispersed in water is still the best way to store it, which limits its application to some extent
[0007] The existing cellulose nanocrystals prepared by acid hydrolysis with sulfuric acid have the disadvantages of poor heat resistance and difficulty in redispersing in the water phase after drying
And after hydrolysis, dialysis is required, the process is cumbersome, and it is not suitable for industrial production

Method used

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  • Highly-heat-resistant redispersible powder cellulose nano-crystal and preparation method thereof
  • Highly-heat-resistant redispersible powder cellulose nano-crystal and preparation method thereof
  • Highly-heat-resistant redispersible powder cellulose nano-crystal and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0048] Add 5g pulp cellulose to 50ml, 55wt% H 2 SO 4After stirring at 50°C for 40 minutes, deionized water was added to terminate the reaction. The mixture was centrifuged at a speed of 10,000 rpm / min for 5 minutes in a high-speed centrifuge, and the supernatant was removed. The lower precipitate was washed with deionized water and then centrifuged again until the upper layer The liquid becomes cloudy. The obtained cellulose nanocrystal suspension was sonicated in an ice-water bath, and stored at 4°C for future use. Adjust the concentration of the prepared cellulose nanocrystal suspension to 1 wt %, take 100 g of the nanocrystal suspension and compound it with 0.33 g of AmimCI type ionic liquid, heat it in a water bath at 60° C. for 3 hours, spray and dry the reaction solution to obtain a cellulose nanocrystal powder , the content of ionic liquid in the prepared powder cellulose nanocrystal is 24.8wt%. The heat resistance and redispersibility data are shown in Table 1.

Embodiment 2

[0050] The type, amount and process flow of the raw materials used are the same as in Example 1, except that the concentration of the prepared cellulose nanocrystal suspension is adjusted to 1 wt%, and 100 g of the nanocrystal suspension is mixed with 0.1 g of AmimCI type ionic liquid. The ionic liquid content in the prepared powder cellulose nanocrystal is 9 wt%. The heat resistance and redispersibility data are shown in Table 1.

Embodiment 3

[0052] The types of raw materials used, the amount and the process flow are the same as in Example 1, except that the concentration of the prepared cellulose nanocrystal suspension is adjusted to 1 wt%, and 100 g of the nanocrystal suspension and 0.01 g of [OMIm] BF 4 Type ionic liquid composite, after heating in a water bath at 50° C. for 0.5 h, the reaction solution is spray-dried to obtain powdered cellulose nanocrystals, and the ionic liquid content in the prepared powdered cellulose nanocrystals is 1 wt%. The heat resistance and redispersibility data are shown in Table 1.

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Abstract

The present invention provides a highly-heat-resistant redispersible powder cellulose nano-crystal and a preparation method thereof. According to the method, cellulose is subjected to acidolysis with sulfuric acid, an ionic liquid is added to the obtained cellulose nano-crystal suspension to form the ionic bond between the ionic liquid and the cellulose nano-crystal, and the reaction liquid is dried to obtain the powder cellulose nano-crystal. According to the present invention, with the preparation method, the heat resistance and the re-dispersion in the water of the cellulose nano-crystals are effectively improved, the problem of the heat degradation during the processing of the acidic cellulose nano-crystals adopted as the nanometer filler and the matrix can be effectively solved, the production process is simplified, and the method is suitable for industrial production.

Description

[0001] 【Technical field】 [0002] The invention belongs to the field of preparation of nanometer materials, in particular to a method for preparing powder cellulose nanocrystals. [0003] 【Background technique】 [0004] Cellulose is the most abundant renewable natural resource in the world. Facing the increasingly serious resource crisis and environmental crisis, the advantages of cellulose's renewable and abundant sources make it a research hotspot in recent years. Cellulose nanocrystals made from cellulose have the characteristics of low density, high aspect ratio, reactive surface, high crystallinity, high Young's modulus, and high strength. The field of composite materials has huge potential application value. [0005] Using sulfuric acid as a hydrolyzing agent to prepare cellulose nanocrystals through acid hydrolysis, the process is relatively simple, and the obtained cellulose nanocrystal suspension can exist stably, which is currently the main method for industrial prod...

Claims

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Application Information

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IPC IPC(8): C08B15/00C08B15/02C08J3/03C08L1/04
CPCC08B15/00C08B15/02C08J3/03C08J2301/04
Inventor 段咏欣宋翔宇张建明
Owner QINGDAO UNIV OF SCI & TECH
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