A method for modifying bamboo based on in-situ encapsulation
By forming a stable modified system of metal-organic framework compounds inside bamboo, the problems of easy volatility, easy oxidation, and uneven distribution of bamboo antifungal agents are solved, achieving long-lasting antifungal effect and improved mechanical properties of bamboo, which is convenient for industrial application.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NANJING FORESTRY UNIV
- Filing Date
- 2024-12-16
- Publication Date
- 2026-07-21
AI Technical Summary
Existing bamboo anti-mildew agents have problems such as easy volatility, easy oxidation, uneven distribution, and negative impact on physical and mechanical properties. In addition, traditional anti-mildew agents are highly toxic and pose serious harm to the environment and human health.
A two-step impregnation method is used to form a stable modified system of natural antifungal agents and metal-organic framework compounds inside bamboo. In-situ encapsulation improves the stability and slow-release performance of the antifungal agents and enhances the physical and mechanical properties of bamboo.
It achieves improved stability and slow-release performance of natural anti-mildew agents, enhanced long-lasting anti-mildew effect and physical and mechanical properties of bamboo, while avoiding the problem of high equipment requirements, making it easy to promote industrialization.
Smart Images
Figure CN119635778B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of bamboo processing technology, and in particular relates to a method for modifying bamboo based on in-situ encapsulation. Background Technology
[0002] Bamboo has a fast growth rate, high yield, and high mechanical strength, and is widely used in interior decoration, furniture manufacturing, flooring, and building structures. However, it is prone to mold growth, which seriously affects the processing and application performance of products, so it is necessary to treat bamboo with anti-mold agents.
[0003] Currently, the main method to improve the mildew resistance of bamboo is through impregnation with mildew inhibitors. Traditional mildew inhibitors have relatively good mildew-resistant effects, but they are highly toxic and often contain heavy metal ions, posing potential hazards to the environment and human health. In recent years, natural antibacterial ingredients such as plant essential oils have been applied to bamboo mildew prevention, showing good results and being safe and environmentally friendly, demonstrating promising application prospects. For example, patent CN115741921A uses modified loofah seed oil to impregnate bamboo to achieve long-lasting mildew resistance. However, natural antibacterial ingredients are highly volatile and easily oxidized, especially during board processing, where they are subjected to high temperature and pressure, easily losing their mildew-resistant effect. Therefore, it is necessary to improve the stability of these mildew inhibitors. Encapsulating the mildew inhibitor inside polymers or porous particles can effectively improve its stability, but the encapsulated particles have problems such as poor penetration and uneven distribution during bamboo impregnation. At the same time, mildew prevention treatment has no significant effect on the physical and mechanical properties of bamboo, and may even have a negative effect. Summary of the Invention
[0004] To overcome the shortcomings and deficiencies of the existing technology, the purpose of this invention is to provide a bamboo modification method based on in-situ encapsulation.
[0005] This invention is implemented as follows: a method for modifying bamboo based on in-situ encapsulation, the method comprising the following steps:
[0006] (1) Place the bamboo sample in the first impregnation tank and maintain the pressure at a negative pressure of 0.06-0.095 MPa for 10-30 min. Add modifier A and maintain the pressure at a negative pressure of 0.4-0.8 MPa for 60-240 min. Then soak it under normal pressure for 8-24 h. Take out the bamboo and air dry it. The modifier A is a mixed solution A dissolved in a solvent, which is composed of a natural antifungal agent and zinc nitrate.
[0007] (2) Place the air-dried bamboo from step (1) into a second impregnation tank and maintain the pressure at a negative pressure of 0.06-0.095 MPa for 10-30 min. Add modifier B and maintain the pressure at a negative pressure of 0.4-0.8 MPa for 60-240 min. Remove the bamboo and cure it at 70-120℃ for 4-12 h to obtain modified bamboo. The modifier B is a mixed solution B dissolved in a solvent. The mixed solution B is composed of imidazole-2-carboxaldehyde and a catalyst. The catalyst is selected from one or more of pyridine, triethylamine, and trioctylamine.
[0008] Preferably, in step (1), the molar ratio of the natural antifungal agent to zinc nitrate in the mixed solution A is 1 to 3:1.
[0009] Preferably, in step (1), the natural antifungal agent is selected from one or more of citral, cinnamaldehyde, and thymol.
[0010] Preferably, in step (2), the preparation process of the modifier B is as follows: imidazole-2-formaldehyde is dispersed in a solvent, heated to 60-100°C, stirred until fully dissolved, cooled to room temperature, insoluble matter is filtered out, catalyst is added, and stirred evenly to obtain modifier B.
[0011] Preferably, in step (2), the mass concentration of the catalyst in modifier B is 2% to 3%.
[0012] Preferably, in steps (1) and (2), the solvent is selected from one or more of methanol, ethanol, and dimethylformamide.
[0013] This invention overcomes the shortcomings of existing technologies and provides a bamboo modification method based on in-situ encapsulation. The invention involves adding bamboo and modifier A to a first impregnation tank, followed by impregnation treatment and air drying to remove solvent from the bamboo surface, resulting in primary modified bamboo. Next, the primary modified bamboo and modifier B are added to a second impregnation tank, followed by impregnation treatment and curing treatment, resulting in final modified bamboo. In this invention, through two-step impregnation, zinc ions in modifier A and imidazole-2-carboxaldehyde in modifier B form a metal-organic framework compound within the bamboo, simultaneously encapsulating the antifungal agent. This process avoids the problems of difficult particle dispersion and impregnation, innovatively forming a stable modification system within the bamboo. This improves the stability and slow-release performance of the natural antifungal agent, giving the bamboo long-lasting antifungal properties, and also enhances the physical and mechanical properties of the bamboo.
[0014] Compared with the shortcomings and deficiencies of existing technologies, the present invention has the following beneficial effects:
[0015] (1) This invention utilizes natural products such as citral, cinnamaldehyde, and thymol as anti-mildew agents for bamboo, which are non-toxic and environmentally friendly.
[0016] (2) This invention utilizes metal-organic framework compounds to encapsulate natural antifungal agents inside bamboo, overcoming the problems of easy volatility and easy oxidation of natural antifungal agents, and achieving long-term antifungal effect on bamboo through the slow release of natural antifungal agents.
[0017] (3) The metal-organic framework compounds used in this invention are rich in aldehyde groups, which can react chemically with the hydroxyl and carboxyl groups of bamboo, thereby improving the dimensional stability and mechanical strength of bamboo.
[0018] (4) The processing technology of this invention has low equipment requirements and is easy to promote industrially. Attached Figure Description
[0019] Figure 1 The graph shows the anti-mildew performance test results of modified bamboo material 2, modified bamboo material 4, and comparative bamboo material 1 and comparative bamboo material 2 before aging in the effective embodiment of the present invention.
[0020] Figure 2 The graph shows the anti-mildew performance test results of modified bamboo material 2, modified bamboo material 4, and comparative bamboo material 1 and comparative bamboo material 2 after aging in the effective embodiment of the present invention. Detailed Implementation
[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0022] Unless otherwise specified, all raw materials and equipment used in the embodiments of the present invention are commercially available products known in the art.
[0023] Example 1
[0024] (1) Dissolve 8.8 mmol of thymol and 8.8 mmol of zinc nitrate in 200 g of methanol and stir until fully dissolved to obtain modifier A;
[0025] Bamboo samples were placed in the first impregnation tank and held under negative pressure of 0.095 MPa for 20 minutes. Modifier A was added to completely submerge the bamboo. The pressure was held at 0.4 MPa for 120 minutes, and then soaked under normal pressure for 12 hours. After removing the bamboo, it was placed in a fume hood and air-dried at room temperature.
[0026] (2) In order to quickly dissolve imidazole-2-carboxaldehyde to form a uniform and transparent solution, 70 mmol imidazole-2-carboxaldehyde was dispersed in 200 g methanol, heated to 60 °C, stirred until fully dissolved, cooled to room temperature, the insoluble matter was filtered off, pyridine was added, and stirred evenly to obtain modifier B, the mass concentration of pyridine in modifier B was 2%.
[0027] The air-dried bamboo from step (1) was placed in the second impregnation tank and kept under a negative pressure of 0.095 MPa for 20 minutes. Modifier B was added to completely submerge the bamboo. The pressure was kept at 0.4 MPa for 120 minutes. The bamboo was then removed and cured at 85°C for 12 hours to obtain modified bamboo 1.
[0028] Example 2
[0029] This Example 2 is basically the same as Example 1, and finally the modified bamboo material 2 is obtained. The difference is that in step (1), 26.4 mmol of thymol and 8.8 mmol of zinc nitrate are fully dissolved in 200g of methanol and stirred until fully dissolved to obtain modifier A.
[0030] Example 3
[0031] (1) Dissolve 26.4 mmol of thymol and 8.8 mmol of zinc nitrate in 200 g of dimethylformamide and stir until fully dissolved to obtain modifier A;
[0032] Bamboo samples were placed in the first impregnation tank and held under negative pressure of 0.095 MPa for 20 minutes. Modifier A was added to completely submerge the bamboo. The pressure was held at 0.4 MPa for 120 minutes, and then soaked under normal pressure for 12 hours. After removing the bamboo, it was placed in a fume hood and air-dried at room temperature.
[0033] (2) Quickly dissolve imidazole-2-carboxaldehyde to form a homogeneous and transparent solution. Disperse 70 mmol imidazole-2-carboxaldehyde in 200 g dimethylformamide, heat to 60 °C, stir until fully dissolved, cool to room temperature, filter out insoluble matter, add trioctylamine, stir evenly, and obtain modifier B. The mass concentration of trioctylamine in modifier B is 3%.
[0034] The air-dried bamboo from step (1) was placed in the second impregnation tank and kept under a negative pressure of 0.095 MPa for 20 minutes. Modifier B was added to completely submerge the bamboo. The pressure was kept at 0.4 MPa for 120 minutes. The bamboo was then removed and cured at 120°C for 12 hours to obtain modified bamboo 3.
[0035] Example 4
[0036] This embodiment 4 is basically the same as embodiment 1, and finally obtains modified bamboo material 4. The difference is:
[0037] In step (1), 26.4 mmol cinnamaldehyde and 8.8 mmol zinc nitrate were fully dissolved in 200 g methanol and stirred until fully dissolved to obtain modifier A.
[0038] Example 5
[0039] (1) Dissolve 17.6 mmol of citral and 8.8 mmol of zinc nitrate in 200 g of dimethylformamide to obtain modifier A;
[0040] Bamboo samples were placed in the first impregnation tank and held under negative pressure of 0.06 MPa for 10 minutes. Modifier A was added to completely submerge the bamboo. The pressure was held at 0.8 MPa for 240 minutes, and then soaked under normal pressure for 24 hours. The bamboo was then removed and air-dried at room temperature.
[0041] (2) Disperse 70 mmol imidazole-2-carboxaldehyde in 200 g ethanol, heat to 100 °C, stir until fully dissolved, cool to room temperature, filter out insoluble matter, add trioctylamine, stir evenly, and obtain modifier B, the mass concentration of trioctylamine in modifier B is 3%;
[0042] The air-dried bamboo from step (1) was placed in the second impregnation tank and kept under a negative pressure of 0.06 MPa for 10 minutes. Modifier B was added to completely submerge the bamboo. The pressure was kept at 0.8 MPa for 240 minutes. The bamboo was then removed and cured at 120°C for 12 hours to obtain modified bamboo 5.
[0043] Example 6
[0044] (1) Dissolve 26.4 mmol of thymol and 8.8 mmol of zinc nitrate in 200 g of methanol to obtain modifier A;
[0045] Bamboo samples were placed in the first impregnation tank and kept under negative pressure of 0.075 MPa for 30 minutes. Modifier A was added to completely submerge the bamboo. The pressure was kept at 0.4 MPa for 60 minutes, and then soaked under normal pressure for 8 hours. After removing the bamboo, it was air-dried at room temperature.
[0046] (2) Disperse 70 mmol imidazole-2-carboxaldehyde in 200 g methanol, heat to 80 °C, stir until fully dissolved, cool to room temperature, filter out insoluble matter, add triethylamine, stir evenly to obtain modifier B, the mass concentration of triethylamine in modifier B is 2.5%;
[0047] The air-dried bamboo from step (1) was placed in the second impregnation tank and kept under a negative pressure of 0.075 MPa for 30 minutes. Modifier B was added to completely submerge the bamboo. The pressure was kept at 0.6 MPa for 60 minutes. The bamboo was then removed and cured at 70°C for 4 hours to obtain modified bamboo 6.
[0048] Comparative Example 1
[0049] Untreated bamboo was dried at 103℃ until completely dry to obtain control bamboo 1.
[0050] Comparative Example 2
[0051] Comparative Example 2 is basically the same as Example 1, and comparative bamboo material 2 is obtained. The difference is that in step (1), 8.8 mmol of zinc nitrate is fully dissolved in 200g of methanol and stirred until fully dissolved to obtain modifier A.
[0052] Comparative Example 3
[0053] (1) Add 26.4 mmol of thymol to 200 g of methanol and stir well to obtain a thymol methanol solution.
[0054] (2) Place the bamboo sample in an impregnation tank and maintain the pressure at a negative pressure of 0.095 MPa for 20 min. Add the above thymol methanol solution to completely immerse the bamboo. Maintain the pressure at 0.4 MPa for 120 min, then soak at normal pressure for 12 h. Finally, take out the bamboo and dry it at 103℃ to constant weight to obtain control bamboo 3.
[0055] Effect Example
[0056] 1. According to the national standard GB / T 18261-2013 "Test Method for the Efficacy of Antifungal Agents in Controlling Molds and Discoloration Fungi on Wood", the bamboo samples obtained in Examples 1-4 and Comparative Examples 1-3 were subjected to antifungal tests. Simultaneously, the bamboo samples obtained in Examples 1-4 and Comparative Examples 1-2 underwent artificial aging tests (one cycle consisted of 24 hours of condensation at 45°C, 3.5 hours of UV irradiation at 60°C, and 0.5 hours of spraying, repeated 7 times), followed by antifungal tests. The results are as follows: Figure 1 , 2 As shown in Table 1.
[0057] Table 1. Mildew resistance ratings of bamboo samples before and after aging.
[0058]
[0059] From Table 1, Figure 1 and Figure 2 It is evident that the modified bamboo prepared by the method of this invention exhibits significant anti-mold properties, with no mold growth observed on the surface of the modified bamboo containing a high content of natural anti-mold agents. After aging, the anti-mold level of the modified bamboo remains essentially unchanged, demonstrating good long-lasting anti-mold performance.
[0060] 2. The bamboo samples of Examples 1-3 and Comparative Examples 1-2 were tested for physical and mechanical properties in accordance with the national standard GB / T 15780-1995 "Test Methods for Physical and Mechanical Properties of Bamboo". The results are shown in Table 2.
[0061] Table 2. Test results of physical and mechanical properties of bamboo samples
[0062]
[0063] As can be seen from Table 2, the dimensional stability, water resistance, and mechanical strength of the modified bamboo prepared by the method of the present invention are significantly improved.
[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for modifying bamboo based on in-situ encapsulation, characterized in that, The method includes the following steps: (1) Place the bamboo sample in the first impregnation tank and maintain the pressure at a negative pressure of 0.06-0.095 MPa for 10-30 min. Add modifier A and maintain the pressure at a negative pressure of 0.4-0.8 MPa for 60-240 min. Then soak it under normal pressure for 8-24 h. Take out the bamboo and air dry it. The modifier A is a mixed solution A dissolved in a solvent, which is composed of a natural antifungal agent and zinc nitrate. (2) Place the air-dried bamboo from step (1) into a second impregnation tank and maintain the pressure at a negative pressure of 0.06-0.095 MPa for 10-30 min. Add modifier B and maintain the pressure at a negative pressure of 0.4-0.8 MPa for 60-240 min. Remove the bamboo and cure it at 70-120℃ for 4-12 h to obtain modified bamboo. The modifier B is a mixed solution B dissolved in a solvent. The mixed solution B is composed of imidazole-2-carboxaldehyde and a catalyst. The catalyst is selected from one or more of pyridine, triethylamine, and trioctylamine.
2. The method as described in claim 1, characterized in that, In step (1), the molar ratio of the natural antifungal agent to zinc nitrate in the mixed solution A is 1 to 3:
1.
3. The method as described in claim 1, characterized in that, In step (1), the natural antifungal agent is selected from one or more of citral, cinnamaldehyde, and thymol.
4. The method as described in claim 1, characterized in that, In step (2), the preparation process of the modifier B is as follows: imidazole-2-formaldehyde is dispersed in a solvent, heated to 60-100°C, stirred until fully dissolved, cooled to room temperature, insoluble matter is filtered out, catalyst is added, and stirred evenly to obtain modifier B.
5. The method as described in claim 4, characterized in that, In step (2), the mass concentration of the catalyst in modifier B is 2% to 3%.
6. The method as described in claim 1, characterized in that, In steps (1) and (2), the solvent is selected from one or more of methanol, ethanol, and dimethylformamide.