Efficient dehydration protection method for water-saturated wooden cultural relics

Abstract

The application discloses a high-efficiency dehydration protection method for water-saturated wooden cultural relics, and specifically comprises the following steps: step 1, preparing a xylitol aqueous solution with a concentration of 30-80 wt%; step 2, soaking the water-saturated wooden cultural relics in the xylitol aqueous solution prepared in step 1 until the xylitol permeates into the water-saturated wooden cultural relics; step 3, taking out the water-saturated wooden cultural relics and removing the excess xylitol on the surface of the water-saturated wooden cultural relics; step 4, spraying a chitosan aqueous solution with a concentration of 1-5 wt% on the surface of the water-saturated wooden cultural relics treated in step 3 for multiple times; and step 5, spraying a glutaraldehyde aqueous solution with a concentration of 2-10 wt% on the surface of the water-saturated wooden cultural relics treated in step 4 for multiple times, then wrapping the water-saturated wooden cultural relics with a breathable film, and airing the water-saturated wooden cultural relics until the constant weight of the water-saturated wooden cultural relics is reached, thereby completing the dehydration and shaping of the water-saturated wooden cultural relics.

Description

Technical Field

[0001] This invention relates to the field of cultural relic restoration technology, specifically to an efficient method for dehydrating and preserving waterlogged wooden cultural relics. Background Technology

[0002] Organic compounds such as sugars have advantages such as being non-toxic, non-corrosive, and having low hygroscopicity under normal air humidity. Studies have shown that wooden objects treated with sugar can maintain their original color and are easy to clean and bond. Furthermore, because sugars have good solubility in water, sugar treatment of water-saturated wooden artifacts can use water as a solvent, making the consolidation method environmentally friendly. Using sugar for dehydration and preservation of water-saturated wooden artifacts can achieve reversible preservation, meeting the principles of reversibility and authenticity in artifact conservation.

[0003] Sugars have long been used to preserve cultural relics. In 1903, a German scientist proposed that treating waterlogged wooden artifacts with a sucrose solution could improve the strength and dimensional stability of the wood. However, experiments revealed that wood treated with sucrose exhibited high hygroscopicity and weak antibacterial properties. In response, in 1904, American scholar Bohr pointed out that when treating waterlogged wooden artifacts with sugar, it was crucial to prevent bacterial and microbial contamination. A fungicide should be added during treatment to prevent mold growth in the solution, which would affect the treatment's effectiveness. In recent years, with in-depth research into sugar-based preservation methods, the materials used have expanded from mannose and sucrose to include trehalose, lactitol, chitosan, and xylitol. Currently, treatment with sugar alcohols often requires heating the waterlogged wooden artifacts, a process that can easily damage the artifacts. Using other sugar alcohols can create a brown film on the surface of the wooden artifacts, affecting the original inscriptions, and their high hygroscopicity makes the wooden artifacts highly susceptible to microbial erosion. Furthermore, to enhance the impregnation effect, organic solvents are often used. These organic solvents are volatile and flammable, and the health of cultural relic conservation personnel may be affected by these solvents during long-term practical operations. Moreover, the storage and use of these solvents pose certain safety hazards. In addition, fungi are the main type of microorganisms that degrade wood. While wood preservatives can achieve good antibacterial effects, they can also have adverse effects on the reinforced wooden cultural relics. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of existing sugar treatment technologies, the purpose of this invention is to provide an efficient method for dehydrating and protecting waterlogged wooden artifacts, so as to solve the problems that existing methods for treating waterlogged wooden artifacts will cause the formation of a brown film on the surface of the wooden artifacts, which affects their appearance, have excessive hygroscopicity, and have weak antibacterial properties.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] An efficient method for dehydrating and preserving waterlogged wooden artifacts includes the following steps:

[0007] Step 1: Prepare a xylitol aqueous solution with a concentration of 30-80 wt%;

[0008] Step 2: Immerse the waterlogged wooden artifact in the xylitol solution prepared in Step 1 until the xylitol penetrates into the interior of the waterlogged wooden artifact.

[0009] Step 3: Remove the waterlogged wooden artifact and clean off any excess xylitol from its surface;

[0010] Step 4: Spray the surface of the water-saturated wooden artifact treated in Step 3 with a chitosan aqueous solution with a concentration of 1-5 wt% multiple times;

[0011] Step 5: Spray the surface of the water-saturated wooden artifact treated in Step 4 with a glutaraldehyde aqueous solution with a concentration of 2-10 wt% multiple times. Then wrap the water-saturated wooden artifact with a breathable film and let it air dry until the water-saturated wooden artifact reaches a constant weight, thus completing the dehydration and shaping of the water-saturated wooden artifact.

[0012] Preferably, the xylitol has a molecular weight of 150 to 200.

[0013] Preferably, in step 2, the waterlogged wooden artifact is immersed in the xylitol aqueous solution prepared in step 1, and replaced with the xylitol aqueous solution prepared in step 1 until the difference between the density of the xylitol aqueous solution after immersion in the waterlogged wooden artifact and the density of the xylitol aqueous solution prepared in step 1 does not exceed 10%.

[0014] Preferably, in step 3, xylitol is removed from the surface of the water-saturated wooden artifact by adsorption.

[0015] Preferably, in step 4, the chitosan aqueous solution is sprayed 1 to 5 times, with an interval of 5 to 20 hours between each application.

[0016] Preferably, in step 5, the glutaraldehyde aqueous solution is sprayed 1 to 10 times, with an interval of 5 to 20 hours between each application.

[0017] Preferably, the drying temperature in step 5 is not higher than 25°C.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. This invention addresses the drawbacks of conventional sugar-treated water-saturated wood, such as the formation of a brown film on the wood surface, affecting aesthetics, and high hygroscopicity and weak antibacterial properties. By using low-molecular-weight xylitol as a filler, the invention enhances the permeability of water-saturated wood artifacts, effectively shortening the permeation cycle and thus further shortening the dehydration and shaping cycle (treatment cycle). Simultaneously, xylitol has numerous active sites and a high hydroxyl content. When xylitol penetrates into the pores of water-saturated wood artifacts, the hydroxyl groups in the xylitol form hydrogen bonds with the hydroxyl groups and ether bonds in the water-saturated wood artifacts, providing support to the pores and thus reinforcing the internal structure of the artifacts.

[0020] 2. This invention also employs the method of spraying chitosan onto the surface of water-saturated wooden artifacts, which effectively improves the weak antibacterial properties of water-saturated wood and prevents microbial degradation of the wood. Furthermore, the amino groups on the chitosan molecules can undergo a Schiff base reaction with the aldehyde groups in the glutaraldehyde structure, while glutaraldehyde also undergoes nucleophilic reactions with the hydroxyl groups in the saturated wooden artifacts, thereby forming a robust cross-linked structure on the surface of the water-saturated wooden artifacts. This improves the dimensional stability of the artifacts. Combined with xylitol, this reinforces the artifacts from the inside, ultimately effectively strengthening both the interior and surface of the artifacts. This gives the artifacts sufficient mechanical properties, preventing damage due to insufficient mechanical properties during subsequent restoration.

[0021] 3. The method described in this invention for treating waterlogged wooden cultural relics requires no equipment, has simple operating requirements, and is easy to operate. It can effectively reduce the operational difficulty for cultural relic protection workers, improve work efficiency, and does not use any harmful organic substances, making the working environment of cultural relic protection workers safer and more comfortable. It is also universal and easy to promote and apply. Attached Figure Description

[0022] Figure 1 This is a SEM image of the original sample of Comparative Example 1 after drying.

[0023] Figures 2a-2c Digital photographs showing the changes in size / shape of water-soaked wood after treatment in each formulation example; wherein the text in each frame corresponds to the concentration (wt%) of xylitol solution, glutaraldehyde solution, and chitosan solution.

[0024] Figure 3 The images show SEM images of the edges and center of the samples treated with xylitol, glutaraldehyde, and chitosan in Examples 1 and 2. Specifically, A represents SEM images of the edges and center of the sample treated with xylitol at different magnifications; B represents SEM images of the edges and center of the sample after spraying with glutaraldehyde and chitosan at different magnifications; and C represents SEM images of the edges and center of the sample after treatment with xylitol / glutaraldehyde-chitosan at different magnifications.

[0025] Figure 4 The image shows the XRD pattern of the sample after processing in the example; where, Figure 4 A is the XRD pattern of the middle part of the xylitol-treated sample; Figure 4 B is the XRD pattern of the edge of the xylitol-treated sample; Figure 4 C represents the XRD pattern of the middle part of the glutaraldehyde-chitosan treated sample; Figure 4 D is the edge XRD pattern of the glutaraldehyde-chitosan treated sample; Figure 4 E represents the XRD pattern of the middle part of the xylitol / (glutaraldehyde-chitosan) treated sample; Figure 4 F is the edge XRD pattern of the xylitol / (glutaraldehyde-chitosan) treated sample.

[0026] Figure 5 Here is the FT-IR image of the sample after processing in the example; wherein, Figure 5 A represents the middle (a) and edge (b) portions of the xylitol-treated sample; Figure 5 B represents the middle (a) and edge (b) portions of the glutaraldehyde-chitosan treated sample; Figure 5 C represents the middle (a) and edge (b) portions of the xylitol / (glutaraldehyde-chitosan) treated sample. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the present invention are within the scope of protection of the present invention.

[0028] Unless otherwise specified in the specific context, the numerical ranges listed herein include upper and lower limits, as well as all integers and fractions within that range, but are not limited to the specific values ​​listed when the range is defined. The term "and / or" as used herein is inclusive; for example, "A and / or B" means only A, or only B, or both A and B.

[0029] I. An efficient method for dehydrating and preserving waterlogged wooden artifacts

[0030] Step 1: Prepare a xylitol aqueous solution with a concentration of 30-80 wt%;

[0031] Step 2: Immerse the waterlogged wooden artifact in the xylitol solution prepared in Step 1 until the xylitol penetrates into the interior of the waterlogged wooden artifact.

[0032] Step 3: Remove the waterlogged wooden artifact and clean off any excess xylitol from its surface;

[0033] Step 4: Spray the surface of the water-saturated wooden artifact treated in Step 3 with a chitosan aqueous solution with a concentration of 1-5 wt% multiple times;

[0034] Step 5: Spray the surface of the water-saturated wooden artifact treated in Step 4 with a glutaraldehyde aqueous solution with a concentration of 2-10 wt% multiple times. Then wrap the water-saturated wooden artifact with a breathable film and let it air dry until the water-saturated wooden artifact reaches a constant weight, thus completing the dehydration and shaping of the water-saturated wooden artifact.

[0035] This invention, through research, discovered that other sugars have large molecular weights, are difficult to dissolve, and require long reinforcement periods. After treatment, water-saturated wood exhibits drawbacks such as a brownish film and poor antibacterial properties, which are detrimental to the display of the original content of the artifact and its long-term preservation. In contrast, xylitol has a small molecular weight, is easily soluble in water, and possesses excellent permeability. Furthermore, xylitol has numerous active sites and a high hydroxyl content. When xylitol penetrates the pores of water-saturated wooden artifacts, the hydroxyl groups in xylitol form hydrogen bonds with the hydroxyl groups and ether bonds in the water-saturated wood, providing support to the pores and thus reinforcing the internal structure of the artifact. It is an excellent filling material with strong affinity for wood. Moreover, this affinity does not cause the collapse of internal capillaries in the wood due to excessive concentration, thus maintaining the original shape of the water-saturated wooden artifact while increasing its strength. Simultaneously, by spraying chitosan and glutaraldehyde onto the surface of water-saturated wooden artifacts, the antibacterial properties of chitosan can effectively improve the weak antibacterial effect of the artifacts, preventing microbial degradation. Furthermore, the amino groups on the chitosan molecules can undergo a Schiff base reaction with the aldehyde groups in the glutaraldehyde structure, while glutaraldehyde also undergoes a nucleophilic interaction with the hydroxyl groups in the saturated wooden artifacts, thus forming a robust cross-linked structure on the surface of the water-saturated wooden artifacts, thereby improving their dimensional stability. Through the combined use of xylitol, chitosan, and glutaraldehyde, both the interior and surface of the water-saturated wooden artifacts are effectively reinforced, ensuring their mechanical properties.

[0036] In some embodiments, the concentration of xylitol is controlled between 30 and 80 wt%. This is because xylitol has many active sites and a high content of hydroxyl groups. When xylitol penetrates into the pores of water-saturated wooden artifacts, the hydroxyl groups in the xylitol form hydrogen bonds with the hydroxyl groups and ether bonds in the water-saturated wooden artifacts, providing support for the pores and thus reinforcing the internal structure of the artifacts. Simultaneously, this method can be applied to water-saturated wooden artifacts with different saturation levels, making the method universally applicable, reducing the operational difficulty for cultural relic conservation workers, and improving work efficiency. Therefore, the concentration of xylitol can be 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, etc., as well as all ranges and sub-ranges between these values. It should be understood that, in the embodiments, any of the above ranges can be combined with any other range.

[0037] In some embodiments, the concentration of chitosan is controlled between 1 and 5 wt%, and the concentration of glutaraldehyde is controlled between 2 and 10 wt%. Chitosan has good antibacterial properties. Spraying chitosan onto the surface of waterlogged wooden artifacts can effectively improve the weak antibacterial properties of waterlogged wood and effectively prevent microbial degradation of the wood. Furthermore, the amino groups on the chitosan molecule can undergo a Schiff base reaction with the aldehyde groups in the glutaraldehyde structure, while glutaraldehyde also undergoes nucleophilic reactions with the hydroxyl groups in the waterlogged wooden artifacts, thereby forming a strong cross-linked structure on the surface of the waterlogged wooden artifacts, thus improving the dimensional stability of the artifacts. Therefore, the mass concentrations of chitosan and glutaraldehyde need to be controlled within a reasonable range. If the mass concentrations of chitosan and glutaraldehyde are too low, chitosan cannot form a cross-linked network shell structure with glutaraldehyde on the surface of the waterlogged wooden artifacts, resulting in the collapse and distortion of the artifacts during natural drying; furthermore, the antibacterial effect of the wood will decrease. However, when the mass concentrations of chitosan and glutaraldehyde are too high, the formation of a dense cross-linked protective film on the surface of waterlogged wooden artifacts results in excessive stress, causing deformation and hindering dehydration. Therefore, the chitosan concentration can be 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, etc., and all ranges and subranges between these values; the glutaraldehyde concentration can be 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, etc., and all ranges and subranges between these values. It should be understood that, in the implementation scheme, any of the above ranges can be combined with any other range.

[0038] In some embodiments, the molecular weight of xylitol is 150-200, more preferably 152.146. A lower molecular weight of xylitol is beneficial because it has good permeability, allowing it to quickly and effectively penetrate into the interior of water-saturated wooden artifacts and effectively shorten the dehydration and setting time. Conversely, if the molecular weight is too high, it will not easily penetrate into the interior of the water-saturated wooden artifacts and may adversely affect the internal structure of the wooden artifacts. Conversely, a molecular weight that is too low will fail to achieve the desired setting effect. Therefore, the molecular weight of xylitol is 150, 152.146, 155, 200, etc., and all ranges and subranges between these values.

[0039] In some embodiments, in step 2, the waterlogged wooden artifact is immersed in the xylitol aqueous solution prepared in step 1, and then replaced with the xylitol aqueous solution prepared in step 1 until the difference between the density of the xylitol aqueous solution after immersion and the density of the xylitol aqueous solution prepared in step 1 does not exceed 10%. This means immersing the waterlogged wooden artifact in the xylitol aqueous solution prepared in step 1 until the density of the xylitol aqueous solution no longer changes. Then, the waterlogged wooden artifact is replaced with a newly prepared xylitol aqueous solution, and the permeation process is repeated until the difference between the density of the xylitol aqueous solution after immersion and the density of the new xylitol aqueous solution is no higher than 10%. Here, the density difference is defined as (density of the newly prepared xylitol aqueous solution in step 1 - density of the xylitol aqueous solution after immersion) ÷ density of the newly prepared xylitol aqueous solution in step 1 × 100% ≤ 10%. The xylitol aqueous solution after immersion refers to the density when the density of the solution no longer changes. To ensure xylitol effectively penetrates into the water-saturated wooden artifacts and achieves osmotic equilibrium, the new xylitol aqueous solution is a freshly prepared xylitol aqueous solution that has not been used to soak water-saturated wooden artifacts.

[0040] In some embodiments, in step 3, xylitol on the surface of a water-saturated wooden artifact is removed by adsorption. Qualitative filter paper can be used for adsorption, but is not limited to it.

[0041] In some embodiments, in step 4, a chitosan aqueous solution is sprayed 1 to 5 times onto the soaked, water-saturated wooden artifact using a spray bottle, with an interval of 5 to 20 hours between each application. Each application is stopped when the surface of the artifact is just moistened. This method can generally treat water-saturated wooden artifacts with different water saturation levels, making the dehydration and shaping method universal, reducing the operational difficulty for cultural relic workers, and improving work efficiency.

[0042] In some embodiments, in step 5, glutaraldehyde aqueous solution is sprayed 1 to 10 times, with an interval of 5 to 20 hours between each spraying, and each spraying is stopped when the surface of the artifact is moistened.

[0043] In some embodiments, the drying temperature in step 5 does not exceed 25°C. The water-saturated wooden artifact is wrapped in a breathable film and dried until it reaches a constant weight, thus completing the dehydration and shaping of the artifact. The breathable film can be a perforated film or a microporous film, and it is placed in a place without direct sunlight to dry naturally.

[0044] II. Examples and Comparative Examples

[0045] Example 1

[0046] Dissolve 60g of xylitol (molecular weight 152.146) in 40g of water to prepare a 60wt% xylitol aqueous solution, and measure its density. Take an ancient waterlogged wooden sample (approximately 3cm x 2cm x 1cm) and immerse it in the prepared xylitol aqueous solution. Test the density of the soaking solution every 3 days. When the density decreases by more than 10%, prepare another xylitol aqueous solution at the same concentration and repeat the soaking of the waterlogged wooden sample. Repeat the above process until the density decrease of the soaking solution in two consecutive soakings does not exceed 10% of the density of the original solution.

[0047] After the density difference between the xylitol aqueous solution of the saturated wood sample and the xylitol aqueous solution of the unsaturated wood sample is no more than 10%, the saturated wood sample is removed, and the residual xylitol on the surface of the saturated wood sample is gently wiped off with qualitative filter paper.

[0048] Wrap the water-saturated wood sample with a perforated plastic film, and then place the water-saturated wood sample in a cool place to air dry until the water-saturated wood sample reaches a constant weight.

[0049] Example 2

[0050] Dissolve 60g of xylitol (molecular weight 152.146) in 40g of water to prepare a 60wt% xylitol aqueous solution, and measure its density. Take an ancient waterlogged wooden sample (approximately 3cm x 2cm x 1cm) and immerse it in the prepared xylitol aqueous solution. Test the density of the soaking solution every 3 days. When the density value decreases by more than 10%, prepare another xylitol aqueous solution with the same concentration and repeat the soaking of the waterlogged wooden sample. Repeat the above process until the density decrease of the soaking solution in two consecutive soakings does not exceed 10% of the density of the original solution.

[0051] After the density difference between the xylitol aqueous solution of the saturated wood sample and the xylitol aqueous solution of the unsaturated wood sample is no more than 10%, the saturated wood sample is removed, and the residual xylitol on the surface of the saturated wood sample is gently wiped off with qualitative filter paper.

[0052] Dissolve 1g of chitosan in 99g of water to prepare a 1wt% chitosan aqueous solution. Spray 8wt% chitosan onto the saturated wood sample using a spray bottle. Spray the chitosan solution twice a day, with an 8-hour interval between each spray, for one day.

[0053] Dissolve 10g of glutaraldehyde in 90g of water to prepare a 10wt% glutaraldehyde aqueous solution. Spray the 8wt% glutaraldehyde solution onto the water-saturated wood sample using a spray bottle. Spray the glutaraldehyde solution twice a day, with an 8-hour interval between each spray, for 3 consecutive days.

[0054] Take out the water-saturated wood sample that has been sprayed with glutaraldehyde, wrap the water-saturated wood sample with a perforated plastic film, and then place the water-saturated wood sample in a cool place to air dry until the water-saturated wood sample reaches a constant weight.

[0055] Example 3

[0056] The example is an adjustment based on Example 2, the difference being that the mass concentration of the xylitol aqueous solution is 10%.

[0057] Example 4

[0058] The example is an adjustment based on Example 2, the difference being that the mass concentration of the xylitol aqueous solution is 30%.

[0059] Example 5

[0060] The example is an adjustment based on Example 2, the difference being that the mass concentration of the xylitol aqueous solution is 50%.

[0061] Example 6

[0062] The example is an adjustment based on Example 2, the difference being that the mass concentration of glutaraldehyde in this example is 2%.

[0063] Example 7

[0064] The example is an adjustment based on Example 2, the difference being that the mass concentration of glutaraldehyde in this example is 6%.

[0065] Example 8

[0066] The example is an adjustment based on Example 2, the difference being that the mass concentration of glutaraldehyde in this example is 8%.

[0067] Comparative Example 1

[0068] Take an ancient waterlogged wooden sample with a length, width, and height of approximately 3cm × 2cm × 1cm. Wrap the waterlogged wooden sample with a perforated plastic film, and then place the waterlogged wooden sample in a cool place to air dry until the waterlogged wooden sample reaches a constant weight.

[0069] The waterlogged wood samples from the examples and comparative examples were measured, and the shrinkage rates and mass loss rates of the longitudinal, radial, and chordal dimensions of the waterlogged wood samples in each example and comparative example are shown in the table below.

[0070] Table 1. Shrinkage and mass loss rates of saturated wooden samples after treatment in the examples and comparative examples.

[0071]

[0072]

[0073] in, Figure 1 Figure 1 shows the SEM image of the original sample after drying in Comparative Example 1. Figure 2 shows digital photographs of the changes in size / shape of the water-soaked wood after treatment in each formulation example; the text in each frame corresponds to the concentration (wt%) of xylitol solution, glutaraldehyde solution, and chitosan solution. Figure 3 The images shown are SEM images of the edges and center of the samples after treatment with xylitol, glutaraldehyde, and chitosan in the examples. Among them, A is the SEM image of the edge and center of the sample after xylitol treatment at different magnifications; B is the SEM image of the edge and center of the sample after glutaraldehyde and chitosan spraying at different magnifications; and C is the SEM image of the edge and center of the sample after xylitol / glutaraldehyde-chitosan treatment at different magnifications. Figure 4 The image shows the XRD pattern of the sample after processing in the example; where, Figure 4 A is the XRD pattern of the middle part of the xylitol-treated sample; Figure 4 B is the XRD pattern of the edge of the xylitol-treated sample; Figure 4 C represents the XRD pattern of the middle part of the glutaraldehyde-chitosan treated sample; Figure 4 D is the edge XRD pattern of the glutaraldehyde-chitosan treated sample; Figure 4 E represents the XRD pattern of the middle part of the xylitol / (glutaraldehyde-chitosan) treated sample; Figure 4 F is the edge XRD pattern of the xylitol / (glutaraldehyde-chitosan) treated sample. Figure 5 Here is the FT-IR image of the sample after processing in the example; wherein, Figure 5 Sample A is treated with xylitol; Figure 5 B is the sample treated with glutaraldehyde-chitosan; Figure 5 C represents the middle (a) and edge (b) portions of the xylitol / (glutaraldehyde-chitosan) treated sample.

[0074] By comparing and analyzing Comparative Example 1, Example 1, and Example 2, it can be seen that, Figures 2a-2c As shown, if a waterlogged wooden artifact is left to air dry without any treatment, the internal fiber channels of the wood will undergo severe collapse and disordered shrinkage and curling. For example... Figures 2a-2cAs shown, if waterlogged wooden artifacts are soaked in xylitol solutions (50wt% or 60wt%) for 7 days, the xylitol acts as a filler and support inside the artifacts, thus hindering the drying shrinkage and collapse of the waterlogged wooden artifacts to some extent after drying. However, xylitol will produce crystalline white patches on the surface of the waterlogged wood, affecting the morphology of the sample. Figures 2a-2c As shown, if a waterlogged wooden artifact is soaked in a xylitol solution (60wt%) for 7 days, and then treated with a 1wt% chitosan spray, with the chitosan evenly sprayed onto the sample surface (3 times a day), and finally treated with an 8wt% glutaraldehyde solution (6 times over 3 days, twice a day, with an 8-hour interval between each spray), the chitosan and glutaraldehyde cross-link on the outer surface of the artifact to form a tight shell structure. The internal filling support of xylitol and the tensile effect of the shell structure formed by the cross-linking of chitosan and glutaraldehyde effectively prevent the collapse and curling of the internal fiber channels of the artifact after drying, thus achieving a good protective effect.

[0075] The XRD patterns of the naturally dried, water-saturated wooden samples obtained in Examples 1 and 2 are shown below. Figure 4 As shown, regardless of the reinforcement treatment, the XRD patterns of the samples generally exhibit obvious cellulose I diffraction characteristics, with the 16° diffraction peak belonging to the 101 crystal plane, the 22° diffraction peak to the 002 crystal plane, and the 35° diffraction peak to the 040 crystal plane. The sample treated with 60wt% xylitol shows greater diffraction intensity for its internal structure than for its external structure. Figure 4 (AB) This is because when xylitol penetrates into the wood, the hydroxyl groups on the xylitol molecules can form hydrogen bonds with the hydroxyl and aldehyde groups in the fiber, which is beneficial to the orderly arrangement of crystals. However, on the outer surface of the wood, excessive xylitol forms cracked crystalline white patches and does not form hydrogen bonds with cellulose; therefore, the intensity of the three diffraction peaks is lower than that on the inner surface of the wood. Figure 4 B). For samples treated with glutaraldehyde-chitosan spraying, since glutaraldehyde and chitosan are only sprayed on the wood surface, the aldehyde groups on the glutaraldehyde structure and the amino groups on chitosan can undergo hydrogen bonding reactions with the hydroxyl groups on the fibers, which is beneficial to improving crystallinity; at the same time, the cross-linked network structure generated by the Schiff base reaction of glutaraldehyde and chitosan also makes the cellulose arrangement more regular to a certain extent. Therefore, in this component, the diffraction peak intensity inside the wood is weaker than that on the surface. Figure 4 CD). However, it can be seen that the diffraction peak intensity inside the wood is also relatively strong in this component (CD). Figure 4C) This is inferred to be due to the penetration effect of glutaraldehyde and chitosan. For samples treated with xylitol / glutaraldehyde-chitosan, the diffraction peak intensity inside the wood is higher than that on the outside. This is mainly because xylitol is precipitated during the spraying of low-concentration glutaraldehyde and chitosan. Therefore, in this component, the diffraction peak intensity inside the wood is higher than that on the outer surface, consistent with the structure obtained from samples treated with xylitol alone. Furthermore, it can be seen that only samples treated with xylitol / glutaraldehyde-chitosan exhibit diffraction peak refinement. This is because, in the topological structure, there are numerous hydrogen bonds inside the wood, while the surface has a dense structure formed by the cross-linking of glutaraldehyde and chitosan, resulting in increased grain size and thus a refinement of the diffraction peak. Figure 4 EF).

[0076] This invention utilizes a biomimetic topological reinforcement method, using xylitol as a filler to effectively support decaying wood. Xylitol (C5H) 12 O5) has a small molecular weight, is easily soluble in water, and has good permeability, effectively filling the pores inside the wood without causing the collapse of internal capillaries due to excessive concentration of the reinforcing agent. Furthermore, the polyhydroxy structure in the xylitol molecule can form hydrogen bonds with carbonyl and aldehyde groups in the fibers, which helps support the wood and improve its mechanical properties. For the wood surface, preservatives such as chitosan and glutaraldehyde are used. By spraying a chitosan and glutaraldehyde solution onto the wood surface, the amino groups on the chitosan molecule can react with the primary aldehydes of glutaraldehyde in a Schiff base reaction, thus forming a weak cross-linking effect on the wood surface. This weak cross-linking topology simultaneously achieves antibacterial properties, compensating for the susceptibility of wood treated with sugar methods to microbial attack.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the technical solutions. Those skilled in the art should understand that any modifications or equivalent substitutions to the technical solutions of the present invention without departing from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A highly efficient method for dehydrating and preserving waterlogged wooden artifacts, characterized in that, Specifically, the steps include the following: Step 1: Prepare a xylitol aqueous solution with a concentration of 50-60 wt%; Step 2: Immerse the waterlogged wooden artifact in the xylitol solution prepared in Step 1 until the xylitol penetrates into the interior of the waterlogged wooden artifact. Step 3: Remove the waterlogged wooden artifact and clean off any excess xylitol from its surface; Step 4: Spray the surface of the water-saturated wooden artifact treated in Step 3 with a chitosan aqueous solution with a concentration of 1-5 wt% multiple times; Step 5: Spray the surface of the water-saturated wooden artifact treated in Step 4 with a glutaraldehyde aqueous solution with a concentration of 2-8 wt% multiple times. Then wrap the water-saturated wooden artifact with a breathable film and let it air dry until the water-saturated wooden artifact reaches a constant weight, thus completing the dehydration and shaping of the water-saturated wooden artifact. In step 2, the waterlogged wooden artifact is immersed in the xylitol aqueous solution prepared in step 1, and then replaced with the xylitol aqueous solution prepared in step 1 until the density of the xylitol aqueous solution after immersion in the waterlogged wooden artifact does not exceed 10% of the density of the xylitol aqueous solution prepared in step 1.

2. The efficient dehydration and preservation method for waterlogged wooden cultural relics according to claim 1, characterized in that, In step 3, xylitol is removed from the surface of water-saturated wooden artifacts by adsorption.

3. The efficient method for dehydrating and preserving waterlogged wooden artifacts according to claim 1, characterized in that, In step 4, the chitosan aqueous solution is sprayed 1 to 5 times, with an interval of 5 to 20 hours between each application.

4. The efficient dehydration and preservation method for waterlogged wooden cultural relics according to claim 1, characterized in that, In step 5, spray glutaraldehyde aqueous solution 1 to 10 times, with an interval of 5 to 20 hours between each application.

5. The efficient method for dehydrating and preserving waterlogged wooden artifacts according to claim 1, characterized in that, The drying temperature in step 5 should not exceed 25°C.

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