阅读说明：本技术 一种耐腐蚀重组竹材的制备方法 (Preparation method of corrosion-resistant recombined bamboo wood ) 是由 周春贵 谭玉海 朱灵丽 于 2019-09-20 设计创作，主要内容包括：本发明公开了一种耐腐蚀重组竹材的制备方法,用乙酰化对竹材进行改性,使竹材中不稳定的羟基变为稳定的酯。从而使竹材具有稳定性和耐腐朽能力。为了避免乙酰化过程中使用催化剂而造成的对竹材性能的破坏,本发明在不使用催化剂的条件下进行乙酰化,通过对干燥后的竹材进行低温等离子体处理,竹材表面被刻蚀,粗糙度变大,有利于乙酰化试剂的渗透,有利于提高乙酰化反应的速度。(The invention discloses a preparation method of corrosion-resistant recombined bamboo wood, which is characterized in that acetylation is used for modifying the bamboo wood, so that unstable hydroxyl in the bamboo wood is changed into stable ester. Thereby the bamboo material has stability and corrosion resistance. In order to avoid the damage to the bamboo performance caused by using a catalyst in the acetylation process, the acetylation is carried out under the condition of not using the catalyst, and the surface of the dried bamboo is etched by carrying out low-temperature plasma treatment on the dried bamboo, so that the roughness is increased, the penetration of an acetylation reagent is facilitated, and the acetylation reaction speed is improved.)

1. The preparation method of the corrosion-resistant recombined bamboo wood is characterized by comprising the following steps:

(1) drying the bamboo wood in a drying box by hot air;

(2) treating the dried bamboo wood with low-temperature plasma gas, wherein the plasma gas treatment conditions are as follows: the pressure is 40-50 Pa, the power is 70-100W, and the processing time is controlled to be 0.5-2 min;

(3) placing the bamboo processed in the step (2) into a reaction container, adding an acylating agent into the container, completely soaking the bamboo into the acylating agent, placing the bamboo at normal temperature for 2-6 hours, gradually heating, and preserving heat for 3-5 hours;

(4) emptying the acylating agent in the container, adding clear water into the container until the bamboo wood is immersed, immersing for 2-3 hours, emptying washing water, and then changing the water for washing for 1-2 times;

(5) and (4) placing the bamboo processed in the step (4) in a drying box, and drying the bamboo for 6-10 hours by using hot air at the temperature of 60-80 ℃.

2. The method for preparing the corrosion-resistant recombined bamboo wood according to claim 1, wherein the acylating agent is a mixture of acetic anhydride and perchloric acid, and the weight ratio of the acetic anhydride to the perchloric acid is 9: 1.

3. the method for preparing the corrosion-resistant recombined bamboo wood according to claim 1, wherein the acylating agent is acetic anhydride.

4. The method for preparing the corrosion-resistant reconstituted bamboo wood according to claim 1, wherein the plasma gas is oxygen.

5. The preparation method of the corrosion-resistant recombined bamboo wood according to claim 1, wherein the step (3) is carried out by standing at normal temperature for 2-6 hours, heating to 90-95 ℃, then carrying out heat preservation for 1-2 hours, finally heating to 95-105 ℃, and then carrying out heat preservation for 2-3 hours.

6. The preparation method of the corrosion-resistant recombined bamboo wood according to claim 1, wherein the reaction vessel is sealed, heated to 90-95 ℃, and then insulated for 1-2 hours, and finally heated to 95-105 ℃ and then insulated for 2-3 hours.

7. The method for preparing the corrosion-resistant recombined bamboo wood according to claim 1, wherein the drying conditions in the step (1) are as follows: drying at 100 + -5 deg.C for more than 8 hr, and oven drying.

Technical Field

The invention belongs to the field of building materials, and particularly relates to a preparation method of corrosion-resistant recombined bamboo wood.

Background

Bamboo is a building material with Chinese characteristics, but China is a big bamboo-producing country, the yield of bamboo is high, and the bamboo has a long history of planting and using. The bamboo material recombined by modern technology is a sustainable development building material, but the bamboo material contains a large amount of sugar and protein, and the content is rich, so the bamboo material is extremely easy to be invaded and corroded by bamboo rot fungi; due to the existence of lignin, hemicellulose and cellulose, the dimension stability and the mildew resistance of the recombined bamboo material in the traditional technology are poor, and the durability and the stability in outdoor application cannot be powerfully guaranteed.

Disclosure of Invention

The invention discloses a preparation method of corrosion-resistant recombined bamboo wood, which is characterized in that acetylation is used for modifying the bamboo wood, so that unstable hydroxyl in the bamboo wood is changed into stable ester. Thereby the bamboo material has stability and corrosion resistance. In order to avoid the damage to the bamboo performance caused by using a catalyst in the acetylation process, the acetylation is carried out under the condition of not using the catalyst, and the hemicellulose in the bamboo is crystallized by carrying out low-temperature plasma treatment on the dried bamboo, so that the strength and the hardness of the material are increased. Meanwhile, the surface of the bamboo is etched, so that the roughness is increased, the permeation of an acetylation reagent is facilitated, and the acetylation reaction speed is increased.

Acetylation of bamboo is an esterification reaction between hydroxyl groups of bamboo and an acetylation reagent, reacting one hydroxyl group of a bamboo component with one acetyl group to form ester. The organic chemical reaction generated during the acetylation treatment of the bamboo wood is as follows:

bamboo material-OH + CH₃COOCOCH₃→ bamboo wood-OCOCH₃＋CH₃COOH

The aim of acetylation treatment of the bamboo is to convert hydroxyl contained in the bamboo into acetyl through organic chemical reaction, and the corrosion resistance of the bamboo is improved due to the reduction of unstable chemical hydroxyl and the swelling effect of stable acetyl in the bamboo.

The technical scheme of the invention is as follows:

a preparation method of corrosion-resistant recombined bamboo wood comprises the following steps:

(1) drying the bamboo wood in a drying box by hot air;

(2) treating the dried bamboo wood with low-temperature plasma gas, wherein the plasma gas treatment conditions are as follows: the pressure is 40-50 Pa, the power is 70-100W, and the processing time is controlled to be 0.5-2 min;

(3) placing bamboo in a reaction container, adding an acylating agent into the container, completely soaking the bamboo in the acylating agent, placing the bamboo at normal temperature for 2-6 hours, gradually heating, and preserving heat for 3-5 hours;

(4) emptying the acylating agent in the container, adding clear water into the container until the bamboo wood is immersed, immersing for 2-3 hours, emptying washing water, and then changing the water for washing for 1-2 times;

(5) and (3) placing the bamboo wood in a drying box, and drying for 6-10 hours by using hot air at the temperature of 60-80 ℃.

In the invention, the speed of the bamboo wood acylation reaction is determined by the diffusion speed of small particles of a reactant entering the interior of cells, the morphological structure of the fiber of the bamboo wood processed by low-temperature plasma gas is obviously changed, part of the cell wall layer is removed, so that the fiber with high reactivity is exposed, and the hemicellulose in the cells on the inner wall of the bamboo wood is crystallized, thereby being beneficial to the permeation of an acetylation reagent and being very beneficial to improving the chemical reactivity of the cellulose.

Preferably, the acylating agent is a mixture of acetic anhydride and perchloric acid, said acetic anhydride and perchloric acid being present in a weight ratio of 9: 1. the acylating agent may also be acetic anhydride. Acetic anhydride is cheap and easy to obtain, has strong acylation capacity, is the acetylation reagent which is most widely applied at present, and acetic anhydride is preferably used as the acetylation reagent in the invention. The acyl chloride is an acetylation reagent with the fastest reaction speed, and in order to improve the reaction speed, 10 percent of acyl chloride is added into acetic anhydride, so that the reaction speed can be effectively improved.

Preferably, the plasma gas is oxygen. When the treatment gas is oxygen, oxygen-containing functional groups are easily accessed to the bamboo surface, and the oxygen-containing functional groups are beneficial to spreading and penetration of the acetylation reagent on the bamboo surface.

Specifically, the step (3) is placed at normal temperature for 2-6 hours, heated to 90-95 ℃, then insulated for 1-2 hours, and finally heated to 95-105 ℃ and insulated for 2-3 hours. The bamboo can be fully infiltrated by the acylating agent when placed at normal temperature, and the acylating agent can be diffused to the cells on the inner wall of the bamboo as far as possible, so that the reaction can be accelerated after the temperature is raised, and the energy consumption is reduced. When the acylation reaction starts, the reaction can be carried out at 90-95 ℃ due to the large excess of the acid anhydride, and the subsequent reaction can be smoothly carried out only by further increasing the temperature along with the reduction of the acid anhydride and the increase of the acetic acid.

Preferably, the temperature of the reaction container in the step (3) is raised to 70-80 ℃ after sealing, the temperature is kept for 1-2 hours, and finally the temperature is raised to 90-105 ℃ and then the temperature is kept for 2-3 hours. The reaction is carried out in a closed container, and the solution in the container is vaporized along with the progress of the reaction, so that the pressure in the container is increased, the solution is favorably diffused into the bamboo wood, and the acylation effect of the bamboo wood is improved. Or, when the bamboo material is soaked at normal temperature, a certain amount of inert gas is injected into the bamboo material, so that the container keeps a certain pressure, and the acylating agent is favorably diffused into the bamboo material.

Preferably, the drying conditions in step (1) are as follows: drying at 100 +/-5 deg.c for over 8 hr to reach constant weight.

The invention has the beneficial effects that:

according to the invention, the bamboo wood is acetylated and modified under the conditions of no solvent and no catalyst, so that the corrosion resistance of the bamboo wood is effectively improved, and before acetylation reaction, the bamboo wood is subjected to low-temperature plasma gas treatment, so that the penetration of an acetylation reagent is facilitated, and the acetylation reaction can be efficiently carried out under the condition of no catalyst.

Detailed Description

The present invention will be further described below by way of specific embodiments. The specific embodiments described herein are merely illustrative of the invention and are not to be construed as limiting the invention.