Dialdehyde nanocellulose with high substitution degree and preparation method thereof

A technology of nanocellulose and high degree of substitution, applied in the field of dialdehyde nanocellulose with high degree of substitution and its preparation, can solve the problem of reducing the selective oxidation efficiency of sodium periodate, unstable nanocellulose, and limiting aldehyde group substitution Problems such as speed, to achieve the effect of short time-consuming, low equipment requirements, and reduced reaction time

Active Publication Date: 2022-06-28
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, in the actual preparation process, due to the instability of nanocellulose, it is easy to gel under the reaction pH condition, which greatly reduces the selective oxidation efficiency of sodium periodate and limits the degree of substitution of aldehyde groups.
And during the freeze-drying process, the aldehyde group is prone to acetalization reaction, which will also limit the degree of substitution of the aldehyde group

Method used

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  • Dialdehyde nanocellulose with high substitution degree and preparation method thereof
  • Dialdehyde nanocellulose with high substitution degree and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0072] Example 1 Preparation of nanocellulose

[0073] 1. Nanocellulose Suspension 1

[0074] Using cellulose as raw material, each gram of cellulose is dispersed in 100mL of phosphate buffer solution (0.05mol / L, pH7) to form a 1% (w / v) slurry, and 0.016g of TEMPO reagent is added, 0.9g NaClO with 80% purity 2 and 3 mL of NaClO solution with a concentration of 2.5% at 60° C. under magnetic stirring at 500 rpm for 6 h, and then added 100 mL of absolute ethanol to terminate the reaction. Use deionized water to repeatedly wash the obtained oxidized cellulose sample until the pH of the solution = 7. The precipitated slurry collected by filtration under reduced pressure is oxidized cellulose, and deionized water is added to the oxidized cellulose to make 1.0% (w / v ) concentration of the suspension, using an ultrasonic cell disruptor (configured with a cylindrical titanium alloy probe with a diameter of 20mm, JY99-IIID, Ningbo Xinzhi Biotechnology Co., Ltd., China), in an ice-wate...

Embodiment 2

[0079] Embodiment 2 A kind of dialdehyde nanocellulose with high degree of substitution

[0080] (1) in the nanocellulose suspension 1 prepared in Example 1, add dilute hydrochloric acid to carry out cation exchange reaction, until the pH of the suspension drops to 2, the suspension after the reaction is sheared at high speed for 10min at a rotating speed of 10000r / min, After mechanical ultrasonic disassembly at 300W power for 15s, the precipitated slurry was collected by decompression filtration using qualitative filter paper, and deionized water was added to the slurry to redisperse into a 1.0% (w / v) concentration of de-sodium nanocellulose suspension. Measure the pH of the suspension. The above-mentioned high-speed shearing, ultrasonic disassembly, filtration under reduced pressure and redispersion were repeated until the pH of the suspension rose to 7.

[0081] (2) Take 50 mL of the 1.0% (w / v) de-sodiumized nanocellulose suspension prepared in step (1), add 50 mL of aceti...

Embodiment 3

[0083] Embodiment 3 A kind of dialdehyde nanocellulose of high degree of substitution

[0084] Same as Example 2, the difference is that the nanocellulose suspension 1 in step (1) is replaced with the nanocellulose suspension 2 prepared in Example 1, and other operations are the same as those in Example 2.

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Abstract

The invention belongs to the field of high polymer materials, and discloses high-substitution-degree dialdehyde nanocellulose and a preparation method thereof.The preparation method of the high-substitution-degree dialdehyde nanocellulose comprises the steps that natural cellulose serves as a raw material, primary alcohol hydroxyl at the C6 position of the cellulose is oxidized through TEMPO, then the primary alcohol hydroxyl is subjected to high-power mechanical ultrasonic disassembling treatment, and the high-substitution-degree dialdehyde nanocellulose is obtained; the preparation method comprises the following steps: firstly, dissolving cellulose in water to form a highly dispersed nano-cellulose fibril suspension, then adding hydrochloric acid to carry out cation exchange reaction, adding water to remove sodium ions in nano-cellulose, then oxidizing hydroxyl groups at C2 and C3 positions in a cellulose glucose structural unit by using sodium periodate, and carrying out reduced pressure filtration to obtain wet dialdehyde nano-cellulose. The adopted reaction method is a homogeneous system, the aldehyde group substitution degree is high, the reaction efficiency is high, the consumption of the oxidizing agent sodium periodate is low, the reaction time is short, the length-diameter ratio and yield of the product are high, separation is easy, and the preparation method is environmentally friendly, simple and efficient.

Description

technical field [0001] The invention belongs to the field of polymer materials, and in particular relates to a dialdehyde nanocellulose with a high degree of substitution and a preparation method thereof. Background technique [0002] Dialdehyde cellulose is a cellulose derivative obtained by selective oxidation of cellulose by sodium periodate, which has advantages in physical and mechanical properties, biocompatibility and biodegradability. The aldehyde group in dialdehyde cellulose basically does not exist in the form of free aldehyde group, and its main structure is hydrated semialdol and intramolecular and intermolecular hemiacetal, so it has high chemical activity and can generate aldehydes and hemiacetals. Many reactions of aldehydes can also react with many substances such as acids, alcohols, amines, hydrazines, acyl groups, etc., and can be used as intermediate compounds in many reactions. And as a renewable resource, dialdehyde cellulose is environmentally friendl...

Claims

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Application Information

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IPC IPC(8): C08B15/02
CPCC08B15/02
Inventor 王兆梅沈珂朱维
Owner SOUTH CHINA UNIV OF TECH
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