Lignin polyurethane and preparation method thereof

A technology of lignin and polyurethane, applied in the field of polymer chemistry, can solve problems such as unfavorable reaction, influence on foam shape, difficult handling, etc., and achieve the effects of increasing environmental friendliness, good solubility, and high chemical activity

Inactive Publication Date: 2010-04-21
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For example, lignosulfonate usually contains a large amount of sodium ions, which will promote the reaction prepolymer to form a gel, affect the foam shape, and be unfavorable to the reaction; ordinary alkali lignin obtained by alkaline cooking is more condensed, and the hydroxyl content Low, so the solubility in polyols is not good, and more alkali lignin does not participate in the reaction with isocyanate and leaves particles in polyurethane products; lignin obtained by oxygen-alkali cooking is oxidized during cooking reaction, so its molecules contain more carboxylate ions, and the solubility in organic solvents is not ideal; this method does not use appropriate methods to remove alkali metal ions (usually sodium ions) in lignin, so it is easy

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Obtaining lignin raw materials: steam explosion treatment of corn stalks under the condition of steam pressure 0.5-1.5MPa for 3-8min, and then washing with hot water at 50-95℃ for 1-3 times to remove polysaccharides produced by hemicellulose degradation, The separated sugar solution is used to prepare ethanol, and the residue contains unreacted lignin and cellulose, which can be extracted with 0.3%-2% sodium hydroxide solution at 60-95°C for 2-5 hours to obtain lignin raw material .

[0041] Dissolve the obtained lignin raw material in non-aqueous pyridine after dehydration, carry out acetylation reaction with acetic anhydride for 2 days under the conditions of oxygen barrier, light-proof and normal temperature, and then wash with ether to precipitate lignin and remove all solvents , dried, and then the acetylated lignin was dissolved in deuterated chloroform, and the hydroxyl content of the lignin was determined by H NMR spectroscopy, and the number of hydroxyl groups ...

Embodiment 2

[0043] (1) Pretreatment of lignin: dissolving 10 g of the lignin raw material obtained in Example 1 with 50 g of acetic acid; filtering the residue with a 60-mesh filter to obtain 57 g of filtrate; adding the filtrate to 570 g of distilled water to precipitate lignin; Separate the precipitate; wash the precipitate with distilled water, 40g of water each time, and the pH value of the washing solution after washing 3 times is 6.5; dry the washed precipitate at 100°C, crush it, and pass it through a 160-mesh sieve, and take the Sieve to obtain pretreated lignin, a total of 8.4g;

[0044] (2) Modification of lignin: add 8g in autoclave by the pretreated lignin of step (1) gained, 0.4g solid sodium hydroxide, seal, alternately evacuate and ventilate nitrogen to deoxygenate, then use Add 8g of ethylene oxide to the metering pump, heat to 100°C, and react at this temperature for 2.5h; then cool to room temperature to obtain modified lignin;

[0045] (3) Dissolution of lignin: add 10...

Embodiment 3

[0049] (1) Pretreatment of lignin: dissolving 10 g of the lignin raw material obtained in Example 1 with 150 g of acetic acid; filtering the residue with a 60-mesh filter screen to obtain 158 g of filtrate; adding the filtrate to 7000 g of distilled water to precipitate the lignin; Separate the precipitate; wash the precipitate with distilled water 5 times, each time with 100 mL of water, until the pH value of the washing solution is 6.8; freeze-dry the washed precipitate at -20°C with a freeze dryer, crush it, and pass it through an 80-mesh sieve, and take Sieve that can be sieved to obtain pretreated lignin, a total of 8.9g;

[0050] (2) Modification of lignin: add 8g in autoclave by the pretreated lignin of step (1) gained, 0.04g solid sodium hydroxide, seal, alternately evacuate and logical nitrogen to deoxygenate, then use Add 8g of propylene oxide to the metering pump, heat to 150°C, and react at this temperature for 3h; then cool to room temperature to obtain modified l...

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PUM

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Abstract

The invention discloses a method for preparing lignin polyurethane, which comprises the following steps of: using an organic solvent to dissolve the lignin which is extracted and separated from residues after producing ethanol from straws by sodium hydroxide; removing the residues, and depositing the mixture with water; separating the lignin; modifying the lignin with an epoxide; dissolving the lignin into a polylol; and finally compounding the lignin with raw materials of isocyanate and the like to obtain a polyurethane material. The lignin used in the method has high reactivity which can be further enhanced through modification so as to obtain a lignin polyurethane material; the polylol used in the method not only can be used as a solvent but also can take part in a synthetic reaction, has good dissolvability to the lignin, and ensures that undissolved lignin particles cannot appear in a polyurethane foam material; and the link for polyurethane synthesis uses no volatile organic solvents, so the production process causes no pollution to the environment, and simultaneously the cost of a polyurethane product is reduced.

Description

technical field [0001] The invention belongs to the field of polymer chemistry, in particular to a preparation method of lignin polyurethane. Specifically, the present invention relates to a method for preparing high-strength rigid polyurethane foam materials from lignin. Background technique [0002] Lignin is one of the three main components in plant fiber raw materials. It is a natural aromatic polymer with a three-dimensional network structure that is second only to cellulose in reserves. In plant fiber raw materials, there are chemical linkages between lignin and cellulose and hemicellulose. There are active groups such as aromatic groups, phenolic hydroxyl groups, alcoholic hydroxyl groups, carbonyl groups, methoxyl groups, carboxyl groups, conjugated double bonds, etc. in lignin molecules, which can carry out a variety of chemical reactions, and are a potential chemical raw material. However, so far, human beings have not fully utilized lignin. The industrial ligni...

Claims

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Application Information

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IPC IPC(8): C08G18/64C08G18/48C08H6/00C08G101/00C08H7/00
Inventor 敖日格勒刘娟娟谌凡更游翔宇杨威
Owner SOUTH CHINA UNIV OF TECH
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