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A method for modifying cellulose without by-product urea

A cellulose and by-product technology, applied in the field of new green processing and modification of polymer materials, can solve the problems of long production cycle, many side reaction products, low urea use efficiency, etc., and achieves low cost, high conversion rate, urea The effect of low content

Active Publication Date: 2016-08-10
WUHAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] The present invention provides a new method for modifying cellulose without by-product urea in order to solve technical problems such as low urea use efficiency, many side reaction products, and long production cycle that are not conducive to industrial implementation; Preparation of cellulose / urea mixture with low urea content, and then heating the mixture to prepare cellulose carbamate, by adjusting the reaction temperature so that the final product obtained by the reaction has no by-products

Method used

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  • A method for modifying cellulose without by-product urea
  • A method for modifying cellulose without by-product urea
  • A method for modifying cellulose without by-product urea

Examples

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Effect test

Embodiment 1

[0027] Soak 500g of cellulose cotton pulp with a molecular weight of 100,000 in 10kg of 1wt% urea aqueous solution, stir at room temperature for 0.5h to fully mix the cellulose and urea solution, and then use a spin dryer to dehydrate for 0.5 minutes. At 800 r / min, the cellulose / urea mixture is separated, and the mass ratio of cellulose and urea in the cellulose / urea mixture is 1:0.01. Take 40g of cellulose / urea mixture and heat it at 180°C for 2.5h. The nitrogen content of the cellulose carbamate obtained by the reaction is 0.2%, and it is dissolved in 6wt% NaOH / 0.4wt% ZnO aqueous solution to obtain 5.0wt% cellulose amino formate solution.

Embodiment 2

[0029] Soak 500g of cellulose cotton pulp with a molecular weight of 100,000 in 10kg of 2wt% urea aqueous solution, stir at room temperature for 1 hour to fully mix the cellulose and urea solution, then use a spin dryer to dehydrate and air-dry at high speed for 3 minutes, and then dehydrate and air-dry The speed is 1500 rev / min, and the cellulose / urea mixture is obtained by separation, and the mass ratio of cellulose and urea in the cellulose / urea mixture is 1:0.02. Take 40g of cellulose / urea mixture and heat it at 170°C for 50min. The nitrogen content of the cellulose carbamate obtained by the reaction is 0.3%, and it is dissolved in 7wt% NaOH / 1.2wt% ZnO aqueous solution to obtain 6.0wt% of cellulose amino formate solution.

Embodiment 3

[0031] Soak 500g of cellulose wood pulp with a molecular weight of 100,000 in 10kg of 5wt% urea aqueous solution, stir at room temperature for 0.5h to fully mix the cellulose and urea solution, then use a spin dryer to dehydrate and air-dry at high speed for 2 minutes, and then dehydrate and air-dry The speed is 2500 rev / min, and the cellulose / urea mixture is obtained by separation, and the mass ratio of cellulose and urea in the cellulose / urea mixture is 1:0.05. Take 40g of cellulose / urea mixture and heat it at 160°C for 2h. The nitrogen content of the cellulose carbamate obtained by the reaction is 0.6%, and it is dissolved in 7.5wt% NaOH / 1.6wt% ZnO aqueous solution to obtain 8.0wt% cellulose carbamate solution.

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Abstract

The invention discloses a method for modifying cellulose through urea without byproducts. The method comprises the following steps: preparing a cellulose / urea mixture by impregnating cellulose with a urea solution or spraying the cellulose with molten state urea, wherein the urea content is low, and the mass ratio of the cellulose to urea is 1:0.01-1:0.1; heating the cellulose / urea mixture at the temperature of 140-200 DEG C, thereby obtaining a cellulose carbamate product, wherein byproducts such as isocyanic acid, biuret and amine isocyanate are not produced in the reaction product, and the reaction product can be well dissolved in sodium hydroxide aqueous solution or a combined aqueous solution consisting of sodium hydroxide and zinc oxide without washing to obtain a transparent cellulose carbamate solution. According to the novel method for modifying cellulose through urea without byproducts, the usage amount of the urea is small, a side reaction or a cross-linking reaction is avoided in the reaction process, the process of washing the reaction products is avoided, the whole synthetic process is simple in steps, the cost is low, and the method is economic, environment-friendly and convenient for industrial implementation.

Description

technical field [0001] The invention relates to a method for modifying cellulose without by-product urea, and belongs to the technical field of novel green processing and modification of polymer materials. Background technique [0002] At present, the traditional and backward viscose method is still used in the production of cellophane and rayon. Due to the heavy use of CS in this production process 2 And cause air, soil, lake serious pollution, and damage human health, the developed country has prohibited this law to produce and shut down these factories. In the face of serious pollution and damage to human health caused by the viscose method, the development of cheap and pollution-free cellulose solvents and new processing methods has become the key to the development of the cellulose industry. The CarbaCell process refers to a new process (Klemm D., Heublein B., Fink H.-P., Angew.Chem.Int.Ed. .2005, 44, 3358-3393.). Compared with the traditional viscose method, this p...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08B15/06
Inventor 周金平付飞亚
Owner WUHAN UNIV