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Nanocrystalline cellulose, its preparation and uses of such nanocrystalline cellulose

a technology of nanocrystalline cellulose and nanocrystalline cellulose, which is applied in the field of nanocrystalline cellulose, can solve the problems of low yield of currently employed preparation procedures, non-trivial and expensive manufacture of nanocrystalline cellulose, and the formidable task of preparing porous inorganic materials

Inactive Publication Date: 2021-04-15
TECH UNIV MUNCHEN
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The patent aims to provide an efficient way to prepare nanocrystalline cellulose without losing significant amounts of the product. It also aims to provide a versatile nanocrystalline cellulose that can be fine-tuned for different applications. The patent also aims to offer a simple methodology for preparing a porous metal oxide with chiral nematic structure, which is easy to perform and doesn't require complicated steps.

Problems solved by technology

Although nanocrystalline cellulose is an industrially promising material, its manufacture remains non-trivial and expensive.
The isolated nanocrystalline cellulose is further purified from the acid through elaborated and time-consuming procedures which involve, inter alia, dialysis against distilled water and require typically several days.
Also, the yield of the currently employed preparation procedures is low and usually does not exceed 20%.
The preparation of these porous inorganic materials, however, remains a formidable task.
Although, by using this method, it is possible to prepare porous oxides with a highly ordered pore structure, a chiral nematic ordering has, so far not been obtained with this general template-base method.
Thereafter, they templated the silica on the nanocrystalline cellulose, but unfortunately, no clear evidence of interfibrillar order was presented.
Altogether, the preparation of chiral nematic metal oxides has so far remained an arduous task, given that it required the preparation of a suitable template first, its isolation and the subsequent use thereof for templating.

Method used

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  • Nanocrystalline cellulose, its preparation and uses of such nanocrystalline cellulose
  • Nanocrystalline cellulose, its preparation and uses of such nanocrystalline cellulose
  • Nanocrystalline cellulose, its preparation and uses of such nanocrystalline cellulose

Examples

Experimental program
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example 1

on of Nanocrystalline Cellulose in Accordance with Embodiments of the Present Invention

[0075]The current prior art preparation procedure of nanocrystalline cellulose (NCC) is based on acidic hydrolysis of the cellulose source and usually leads to a maximal yield of ca. 20%. Additionally further purification of the crystallites from the resins of sulfuric acid is based on time consuming dialysis process.

[0076]Within embodiments of the present invention, the present inventors have changed the synthesis procedure in the way that it allows a separation of cellulose nanocrystals from solution without significant loss of the product. Yields obtained according to the present invention are 80%-95%. This is achieved by direct addition of a desired base at the end of the hydrolysis process and exclusion of repeated dilution and dialysis steps using water. In certain embodiments, the base is added in equimolar amount to the sulfuric acid which was used in the hydrolysis. When the base is e.g. ...

example 2 — embodiment

Example 2—Embodiment: Preparation of Nanocrystalline Cellulose (NCC)

[0083]In an exemplary synthesis, 2 g of cotton linters were placed in an Erlenmeyer bottle. 20 ml of 65% sulfuric acid was added to the bottle with cotton linters and everything was placed in the water bath at 60° C. and vigorously stirred for three hours. Four different temperatures, namely 45, 50, 60 and 70° C., were tested for the hydrolysis procedure. 15.15 g of NaOH were dissolved in 100 ml water. After three hours, the Erlenmeyer bottle with hydrolyzed cotton linters was removed from the water bath and 30 ml of water were added into the flask in order to adjust the viscosity of the dispersion. If necessary, such dilution step can be avoided if the base that is used is approximately diluted. In any case, the method according to the present invention does not use repeated dilution steps with water to stop the hydrolysis. In order to stop the hydrolysis, the diluted dispersion was directly mixed with NaOH solutio...

example 3

on of Nanocrystalline Cellulose-Metal Oxide-Composite Materials and / or Preparation of Porous Metal Oxides in Accordance with Embodiments of the Present Invention

[0091]According to this aspect of the present invention, it is also possible to produce a nanocrystalline cellulose-metal oxide-composite material which can subsequently be transformed into a porous oxide having a chiral nematic structure upon annealing. This can be achieved if the isolation of the nanocrystalline cellulose (NCC) and the preparation of the composite material are performed concomitantly in one pot.

[0092]In EXAMPLES 1 and 2 above it was shown that the successful separation of NCC after the hydrolysis can be achieved by addition of a desired base at the end of the hydrolysis process to stop the hydrolysis process. This addition of a base leads to a neutralization process between the negatively charged sulfuric ions and positively charged base cations, e.g. according to the equation (when the base is MeOH)

2MeOH(...

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Abstract

The present invention relates to nanocrystalline cellulose, an efficient way of its preparation and to uses of such nanocrystalline cellulose. The present invention also relates to porous metal oxides having a chiral nematic structure which are prepared using nanocrystalline cellulose.

Description

CROSS REFERENCE TO A RELATED APPLICATION[0001]This application is a Divisional Application of co-pending U.S. application Ser. No. 15 / 517,779, filed Apr. 7, 2017, now U.S. Pat. No. 10,875,934; which is the National Stage Application of International Application Number PCT / EP2015 / 073438, filed Oct. 9, 2015; which claims priority to European Patent Application No. 14188526.9, filed Oct. 10, 2014; all of which are incorporated herein by reference in their entirety.FIELD OF INVENTION[0002]The present invention relates to nanocrystalline cellulose, an efficient way of its preparation and two uses of such nanocrystalline cellulose. The present invention also relates to porous metal oxides having a chiral nematic structure which are prepared using nanocrystalline cellulose.BACKGROUND OF THE INVENTION[0003]More specifically the present invention relates to a method of preparing nanocrystalline cellulose, to a nanocrystalline cellulose prepared by such method, and to uses of such nanocrystal...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C08B15/08C01G1/02C01G9/02C01G45/02C01G3/02
CPCC08B15/08C01G1/02C01P2006/16C01G45/02C01G3/02C01G9/02
Inventor MÜLLER, VESNABRIESEN, HEIKO
Owner TECH UNIV MUNCHEN