Wood reinforcing agent as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of cultural relic repair, and provides a wood reinforcing agent and a preparation method and application thereof. The wood reinforcing agent comprises the following components in concentration: 9-15 ppm of carbon quantum dots, 25-50 wt% of polyethylene glycol and the balance of a solvent, the surfaces of the carbon quantum dots contain amino and carboxyl. Due to the fact that-NH2 and-COOH functional groups on the surfaces of the carbon quantum dots (CQDs) can form a large number of hydrogen bonds and covalent amido bonds with polyethylene glycol (PEG) and wood components, a three-dimensional cross-linked network is constructed, the wood reinforcing agent provided by the invention can be more firmly combined in wood cell walls, migration and leakage of PEG are effectively prevented, and a more durable and stable reinforcing effect is provided. Due to the fact that the CQDs have efficient antibacterial performance, the wood reinforcing agent can provide long-acting antibacterial and corrosion-resistant protection which traditional PEG does not have for wood cultural relics, microbial degradation is inhibited, and the service life of the cultural relics is prolonged.

Description

Technical Field

[0001] This invention relates to the field of cultural relic restoration technology, and in particular to a wood consolidation agent, its preparation method, and its application. Background Technology

[0002] Wooden artifacts recovered from the sea (such as the "Nanhai No. 1" shipwreck) are invaluable material evidence of ancient Chinese maritime trade and shipbuilding technology. However, these artifacts have endured hundreds of years of high salinity, high temperatures, and microbial erosion on the seabed, resulting in severe degradation of their lignocellulose molecular chains and a significant decrease in mechanical strength, posing a significant challenge to subsequent conservation efforts. Currently, polyethylene glycol (PEG) is the most widely used and classic consolidating agent for the dehydration and reinforcement of recovered wooden artifacts. PEG can penetrate into the wood tissue, replacing water molecules and thus improving the dimensional stability of the artifacts, and its material and equipment costs are relatively low. However, the interaction between PEG molecules and wood components (cellulose, hemicellulose, lignin) is only weak through physical adsorption and hydrogen bonding, lacking strong and stable binding anchors. When environmental temperature and humidity change, the penetrated PEG can easily migrate and precipitate from the wood, resulting in a short-lasting reinforcement effect and potentially forming harmful crystals on the surface of the artifacts. Summary of the Invention

[0003] In view of this, the object of the present invention is to provide a wood strengthening agent, its preparation method, and its application. The wood strengthening agent provided by the present invention is not easily migrated or leaked.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a wood strengthening agent comprising components at the following concentrations: Carbon quantum dots 9~15ppm, polyethylene glycol 25~50wt%, balance solvent; The surface of the carbon quantum dots contains amino and carboxyl groups.

[0005] Preferably, the molecular weight of the polyethylene glycol is 1000-4000.

[0006] Preferably, the method for preparing the carbon quantum dots includes the following steps: Organic carbon source, organic nitrogen source, polyethylene glycol and water are mixed and microwaved to obtain the carbon quantum dots.

[0007] Preferably, in the preparation process of the carbon quantum dots, the molecular weight of the polyethylene glycol is 1000~4000; The organic carbon source is a polycarboxylic acid, which includes citric acid and / or malic acid; The organic nitrogen source includes one or more of urea and amino acids; The molar ratio of the organic nitrogen source to the organic carbon source is 4~35:1; The mass ratio of the organic carbon source to polyethylene glycol is 3:1; The mass ratio of the organic carbon source to water is 0.6:10mL.

[0008] Preferably, the power of the microwave processing is 400~600W.

[0009] Preferably, after the microwave treatment is completed, the process further includes: mixing the obtained char-like solid microwave treatment system with water, and then performing ultrasonic dispersion and centrifugation in sequence to remove insoluble matter and obtain a suspension; and then performing dialysis and freeze-drying on the suspension in sequence to obtain the carbon quantum dots.

[0010] Preferably, the ultrasonic dispersion time is 10-30 min; the centrifugation speed is 9000-11000 rpm and the time is 4-6 min; the molecular weight cutoff of the dialysis bag used for dialysis is 400-600 Da and the dialysis time is 36-60 h; the freeze-drying temperature is -40℃ and the time is 36-60 h.

[0011] This invention also provides a method for preparing the wood strengthening agent described in the above technical solution, comprising the following steps: Carbon quantum dots were dispersed in a portion of water to obtain a carbon quantum dot stock solution; Disperse polyethylene glycol in the remaining water to obtain a polyethylene glycol solution; The carbon quantum dot stock solution and the polyethylene glycol solution are mixed to obtain the wood strengthening agent.

[0012] Preferably, the concentration of the carbon quantum dot stock solution is 240-360 ppm, and the concentration of the polyethylene glycol solution is 25-50 wt%.

[0013] The present invention also provides the application of the wood consolidating agent described in the above technical solution or the wood consolidating agent prepared by the preparation method described in the above technical solution in the protection of wooden cultural relics.

[0014] This invention provides a wood strengthening agent. The wood strengthening agent of this invention has the following advantages: (1) Since the -NH2 and -COOH functional groups on the surface of carbon quantum dots (CQDs) can form a large number of hydrogen bonds and covalent amide bonds with polyethylene glycol (PEG) and wood components (cellulose, hemicellulose, lignin) to construct a three-dimensional cross-linked network, the wood strengthening agent provided by the present invention can be more firmly bound to the wood cell wall, effectively preventing the migration and leakage of PEG, and providing a more durable and stable strengthening effect.

[0015] (2) Since CQDs have highly efficient antibacterial properties (confirmed by the inhibition zone experiment), the wood consolidation agent of the present invention can provide wooden cultural relics with long-lasting antibacterial and anti-corrosion protection that traditional PEG does not have, inhibit microbial degradation, and extend the life of cultural relics. Attached Figure Description

[0016] Figure 1 The image shows a transmission electron microscope (TEM) image of the CQDs powder obtained in Example 1. Figure 2 An atomic force microscope (AFM) image of the CQDs powder obtained in Example 1; Figure 3 The average particle size of the CQDs powder obtained in Example 1; Figure 4 Atomic force microscopy (AFM) images of the PEG 2000; Figure 5 An atomic force microscope (AFM) image of the CQDs / PEG wood consolidator obtained in Example 1; Figure 6 Leakage was treated with pure PEG 2000 solution (concentration 48.08 wt%) and CQDs / PEG wood strengthening agent of Example 1; Figure 7 The effects of different CQDs / PEG wood strengthening agents on Examples 1 and 7 and Comparative Example 3 Trametes versicolor (TV) and Postia placenta Minimum inhibitory concentration (MIC) of (Pp); Figure 8 For PEG, the CQDs / PEG wood strengthening agent obtained in Example 1 has the effect on... Trametes versicolor (TV) Postia placenta (Pp) and Aspergillus niger (An) antifungal properties; Figure 9 The leakage phenomenon of wood treated with CQDs / PEG wood strengthening agent in Examples 2-4 and Comparative Example 1; Figure 10 The antifungal properties of the CQDs / PEG wood strengthening agents in Examples 2-4 and Comparative Example 1; Figure 11 Leakage was observed in wood treated with CQDs / PEG wood strengthening agents in Examples 5-6 and Comparative Examples 2 and 4; Figure 12 The antifungal properties of the CQDs / PEG wood strengthening agents in Examples 5-6 and Comparative Examples 2 and 4. Detailed Implementation

[0017] This invention provides a wood strengthening agent comprising components at the following concentrations: Carbon quantum dots 9~15ppm, polyethylene glycol 25~50wt%, balance solvent; The surface of the carbon quantum dots contains amino and carboxyl groups.

[0018] Unless otherwise specified, the raw materials used in this invention are preferably commercially available products.

[0019] The wood strengthening agent provided by this invention comprises 9-15 ppm of carbon quantum dots, preferably 9 ppm, 9.2 ppm, 10 ppm, 11 ppm, 11.5 ppm, 12 ppm, 13 ppm, 13.85 ppm, 14 ppm, or 15 ppm. In this invention, the surface of the carbon quantum dots contains amino and carboxyl groups.

[0020] In this invention, the method for preparing the carbon quantum dots preferably includes the following steps: The carbon quantum dots are obtained by mixing an organic carbon source, an organic nitrogen source, polyethylene glycol, and water, followed by microwave treatment. In this invention, the molecular weight of the polyethylene glycol is preferably 1000-4000, specifically 1000, 1500, 2000, 2500, 3000, 3500, or 4000. In this invention, the organic carbon source is preferably a polycarboxylic acid, preferably including citric acid and / or malic acid, more preferably citric acid. In this invention, the organic nitrogen source preferably includes one or more of urea and amino acids, more preferably urea; the amino acid preferably includes L-lysine. In this invention, the molar ratio of the organic nitrogen source to the organic carbon source is preferably 4-35:1, specifically 16.67:1 or 33.33:1. In this invention, the mass ratio of the organic carbon source to polyethylene glycol is preferably 3:1. In this invention, the mass ratio of the organic carbon source to water is preferably 0.6:10 mL. In this invention, the power of the microwave treatment is preferably 400-600W, more preferably 500W; the microwave treatment time is not specifically limited, as long as the microwave-treated system transforms into a charred solid state; in one specific embodiment of this invention, the microwave treatment time is preferably 5-10 minutes. After the microwave treatment, this invention preferably further includes: mixing the obtained charred solid microwave-treated system with water, sequentially performing ultrasonic dispersion and centrifugation to remove insoluble matter, obtaining a suspension; sequentially dialysis and freeze-drying the suspension to obtain the carbon quantum dots. In this invention, the water is preferably deionized water. In this invention, the ultrasonic dispersion time is preferably 10-30 minutes, more preferably 20 minutes. In this invention, the centrifugation speed is preferably 9000-11000 rpm, more preferably 10000 rpm; the centrifugation time is preferably 4-6 minutes, more preferably 5 minutes. In this invention, the molecular weight cutoff of the dialysis bag used for dialysis is preferably 400-600 Da, more preferably 500 Da; the dialysis time is preferably 36-60 h, more preferably 48 h. In this invention, the freeze-drying temperature is preferably -40℃, and the time is preferably 48 h. In this invention, during the preparation of carbon quantum dots, the role of the organic carbon source is to form the carbon skeleton core and to impart carboxyl groups to the carbon quantum dots; one role of the organic nitrogen source is as a nitrogen dopant for the carbon skeleton core, i.e., to form a nitrogen-doped carbon skeleton core and to impart amino and carboxyl groups to the carbon quantum dots; polyethylene glycol basically does not participate in the formation of the carbon skeleton core, but increases the molecular chain density and length on the surface of CQDs to increase the binding strength between the carbon quantum dots and subsequent PEG.

[0021] The wood strengthening agent provided by this invention comprises 25-50 wt% polyethylene glycol, preferably 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 48.08 wt%, or 50 wt%. In this invention, the molecular weight of the polyethylene glycol is preferably 1000-4000, specifically preferably 1000, 1500, 2000, 2500, 3000, 3500, or 4000.

[0022] The wood strengthening agent provided by the present invention includes a balance of solvent, wherein the solvent preferably comprises one or more of water and alcohol, more preferably water. In the present invention, the alcohol preferably comprises ethanol.

[0023] The wood consolidation agent of this invention incorporates carbon quantum dots (CQDs) with amino and carboxyl groups modified on their surface. The -NH2 and -COOH functional groups on the surface of the CQDs can form numerous hydrogen bonds and covalent amide bonds with PEG and wood components, constructing a three-dimensional cross-linked network. Therefore, the wood consolidation agent of this invention can bind more firmly within the wood cell wall, effectively preventing PEG migration and leakage, and providing a more durable and stable consolidation effect. Simultaneously, due to the inherent and highly efficient antibacterial properties of CQDs (confirmed by inhibition zone experiments), the wood consolidation agent of this invention can provide wooden artifacts with long-lasting antibacterial and preservative protection that traditional PEG lacks, inhibiting microbial degradation and extending the lifespan of artifacts.

[0024] This invention also provides a method for preparing the wood strengthening agent described in the above technical solution, comprising the following steps: Carbon quantum dots were dispersed in a portion of water to obtain a carbon quantum dot stock solution; Disperse polyethylene glycol in the remaining water to obtain a polyethylene glycol solution; The carbon quantum dot stock solution and the polyethylene glycol solution are mixed to obtain the wood strengthening agent.

[0025] This invention disperses carbon quantum dots in a portion of water to obtain a carbon quantum dot stock solution. In this invention, the concentration of the carbon quantum dot stock solution is preferably 240-360 ppm, specifically preferably 240 ppm, 300 ppm, or 360 ppm.

[0026] In this invention, polyethylene glycol is dispersed in the remaining water to obtain a polyethylene glycol solution. In this invention, the concentration of the polyethylene glycol solution is preferably 25-50 wt%.

[0027] After obtaining the carbon quantum dot stock solution and the polyethylene glycol solution, the present invention mixes the carbon quantum dot stock solution and the polyethylene glycol solution to obtain the wood strengthening agent.

[0028] In one specific embodiment of the present invention, the volume ratio of the carbon quantum dot stock solution to the polyethylene glycol solution is preferably 1:25.

[0029] In this invention, the mixing of the carbon quantum dot stock solution and the polyethylene glycol solution is preferably carried out under stirring conditions, the stirring speed is preferably 60~200 rpm, more preferably 120 rpm; the stirring time is preferably 5~10 min.

[0030] The present invention also provides the application of the wood consolidating agent described in the above technical solution or the wood consolidating agent prepared by the preparation method described in the above technical solution in the protection of wooden cultural relics.

[0031] In this invention, the wooden artifacts preferably include underwater wooden artifacts or non-underwater wooden artifacts, and the underwater wooden artifacts are preferably marine underwater wooden artifacts.

[0032] This invention also provides a method for protecting wooden cultural relics, comprising the following steps: Wooden artifacts are immersed in the wood consolidating agent described in the above technical solution for consolidation treatment.

[0033] In this invention, the immersion temperature is preferably room temperature, that is, no additional heating or cooling is required, and the immersion time is preferably 0.5 to 1.0 h.

[0034] In this invention, the reinforcement treatment is the process of immersing the wooden artifact in the wood reinforcement agent.

[0035] After the reinforcement treatment is completed, the present invention preferably further includes: removing the soaked wooden artifact and allowing it to air dry naturally. In the present invention, the natural drying is preferably achieved by placing the soaked wooden artifact in the air, allowing the moisture or solvent to evaporate through natural air circulation and temperature, thereby achieving the purpose of drying.

[0036] The following detailed description of the wood strengthening agent, its preparation method, and its application provided by the present invention, with reference to specific embodiments, should not be construed as limiting the scope of protection of the present invention.

[0037] Example 1 (1) Preparation of CQDs: Urea (6.0 g, 0.1 mol), citric acid (0.6 g, 0.003 mol), PEG 2000 (0.2 g) were dissolved in deionized water (10 mL) to form a clear solution and placed in an Erlenmeyer flask. The solution was reacted at 500 W microwave power for 5 min to obtain a char-like solid microwave treatment system. The obtained char-like solid microwave treatment system was dissolved in deionized water, ultrasonically dispersed for 20 min, and centrifuged (10000 rpm, 5 min) to remove insoluble matter to obtain a suspension. The suspension was purified by dialysis (the molecular weight cutoff of the dialysis bag was 500 Da, and the dialysis reagent was water) for 48 h, and then lyophilized (-40℃, 48 h) to obtain CQDs powder.

[0038] (2) Preparation of CQDs / PEG composite reinforcement agent: CQDs powder was dispersed in water to prepare a CQDs stock solution of 360 ppm. The CQDs stock solution was brownish-red and had blue fluorescence. PEG 2000 was dispersed in water to form a PEG 2000 solution of 50 wt%. 2 mL of CQDs stock solution was mixed with 50 mL of PEG 2000 solution and stirred at 120 rpm for 5 min to form a uniform and stable CQDs / PEG wood reinforcement agent. Finally, the concentration of CQDs was 13.85 ppm and the concentration of PEG was 48.08 wt%. The obtained CQDs / PEG wood reinforcement agent was uniform and stable.

[0039] Example 2 The difference from Example 1 is that in the process of preparing CQDs powder, the amount of urea is 3.0g (0.05mol), the amount of citric acid is 0.6g, the amount of PEG-2000 is 0.2g, and the rest is the same as in Example 1.

[0040] Comparative Example 1 The difference from Example 1 is that in the process of preparing CQDs powder, the amount of urea is 0.6g (0.01mol), the amount of citric acid is 0.6g, the amount of PEG-2000 is 0.2g, and the rest is the same as in Example 1.

[0041] Example 3 The difference from Example 1 is that urea was replaced with L-lysine in the preparation of CQDs powder, otherwise it is the same as Example 1.

[0042] Example 4 The difference from Example 1 is that citric acid was replaced with malic acid in the process of preparing CQDs powder, otherwise it is the same as Example 1.

[0043] Example 5 The difference from Example 1 is that PEG 2000 was replaced with PEG 4000 in the process of preparing CQDs powder, otherwise it is the same as Example 1.

[0044] Example 6 The difference from Example 1 is that the concentration of the CQDs stock solution was adjusted to 300 ppm during the preparation of the CQDs / PEG wood strengthening agent.

[0045] Comparative Example 2 The difference from Example 1 is that the concentration of the PEG 2000 solution was adjusted to 20wt% during the preparation of the CQDs / PEG wood strengthening agent.

[0046] Example 7 The difference from Example 1 is that the concentration of the CQDs stock solution was adjusted to 240 ppm during the preparation of the CQDs / PEG wood strengthening agent.

[0047] Comparative Example 3 The difference from Example 1 is that the concentration of the CQDs stock solution is adjusted to 60ppm, 120ppm or 180ppm during the preparation of the CQDs / PEG wood strengthening agent.

[0048] Comparative Example 4 The difference from Example 1 is that PEG 2000 is omitted in the preparation of CQDs powder, otherwise it is the same as Example 1.

[0049] (1) Physical characterization The CQDs powder obtained in Example 1 was characterized, and the results are as follows: Figures 1-3 As shown, Figure 1 Transmission electron microscopy (TEM) images of CQDs powder, with the inset showing an image of lattice fringes, from... Figure 1 The illustration shows that the lattice spacing of CQDs is approximately 0.34 nm, which matches the in-plane lattice spacing of graphene.

[0050] Figure 2 Atomic force microscopy (AFM) images of CQDs powder, from Figure 2 It can be seen that the height of CQDs is approximately 5nm.

[0051] Figure 3 The average particle size of CQDs powder, from Figure 3 It can be seen that the average particle size of CQDs is 2.4 nm.

[0052] Figure 4 Images of the PEG 2000 using atomic force microscopy (AFM). Figure 5The image shown is an atomic force microscope (AFM) image of the CQDs / PEG wood consolidator obtained in Example 1. Figure 4 and Figure 5 It can be seen that the integration-induced effect of CQDs significantly alters the PEG morphology. Compared to smooth, isolated pure PEG chains (approximately 200 nm long), the CQDs / PEG wood stabilizer exhibits longer molecular chains and a large number of nanoscale micro-protrusions attached to its surface. This obvious surface roughening, coupled with the visible adhesion of CQDs, confirms the in-situ loading of CQDs onto the polymer backbone and indicates the formation of interfacial interactions.

[0053] (2) The strengthening (swelling) effect of CQDs / PEG wood consolidating agent on wood cells Test Procedure: Poplar wood blocks (modern timber) and the Nanhai No. 1 shipwreck sample (archaeological timber) were respectively immersed in pure PEG 2000 solution (concentration 48.08wt%) and the CQDs / PEG wood consolidation agent of Example 1 at room temperature for 0.5 h. After consolidation treatment, leakage was observed at room temperature, and the results are as follows. Figure 6 As shown, Figure 6 Leakage was observed in wood treated with PEG solution and the CQDs / PEG wood strengthening agent of Example 1, wherein (a) wood treated with PEG 2000 solution and (b) wood treated with CQDs / PEG wood strengthening agent. Figure 6 It can be seen that the wood treated with CQDs / PEG wood consolidation agent showed no obvious leakage, which was significantly better than the pure PEG group, proving that CQDs can effectively prevent PEG leakage.

[0054] (3) Verification of the antibacterial properties of CQDs / PEG wood strengthening agent Test procedure: The inhibition zone method was used, and the CQDs were determined against brown rot fungi (CQDs) using the agar dilution method. Postia placenta Pp) and white rot fungi ( Trametes versicolor The minimum inhibitory concentration (MIC) of CQDs / PEG wood consolidating agents (Tv) was determined by the following procedure: Different CQDs / PEG wood consolidating agents from Examples 1 and 7 and Comparative Example 3 were dried into gel blocks, placed on PDA medium coated with Pp or Tv, and incubated for 7 days. The results are as follows: Figure 7 As shown, Figure 7 The MICs of different CQDs / PEG wood strengthening agents for Tv and Pp in Examples 1 and 7 and Comparative Example 3. Scale bar: 2cm. Figure 7It can be seen that a clear inhibition zone appeared around the CQDs / PEG gel block, while no inhibition zone was found in the pure PEG treatment group, proving that the CQDs / PEG composite has excellent antifungal ability. With the increase of CQDs concentration, the hyphal diameter of Pp and Tv showed a significant decreasing trend. The results showed that the MIC of CQDs against Pp and Tv were 240 ppm and 360 ppm, respectively.

[0055] The antibacterial properties of PEG and CQDs / PEG wood strengthening agent (Example 1) were further tested, and the results are as follows: Figure 8 As shown, Figure 8 For PEG, CQDs / PEG wood strengthening agents, the effects of Tv, Pp and Aspergillus niger The antifungal properties of (An) were assessed using a scale bar of 2 cm. Results showed that fungal hyphae completely covered the PEG surface, while the CQDs / PEG wood reinforcement agent exhibited no obvious fungal colonies, demonstrating superior antifungal performance. Furthermore, the CQDs / PEG wood reinforcement agent also showed 100% control efficiency against common Aspergillus niger.

[0056] The leakage of wood treated with CQDs / PEG wood strengthening agent in Examples 2-4 and Comparative Example 1 was tested using method (2), and the results are as follows: Figure 9 As shown; the antifungal properties of the CQDs / PEG wood strengthening agents in Examples 2-4 and Comparative Example 1 were tested using method (3), and the results are as follows. Figure 10 As shown, from Figure 9 and Figure 10 It can be seen that in Example 2, the molar ratio of urea to citric acid was in the range of 4~35:1, resulting in CQDs with excellent antifungal properties and enhanced binding function. In Comparative Example 1, the molar ratio of urea to citric acid was not in the range of 4~35:1, and CQDs with excellent antifungal properties and enhanced binding function could not be prepared. In Example 3, L-lysine was used instead of urea, and CQDs with antibacterial and enhanced binding functions could also be prepared. In Example 4, malic acid was used instead of citric acid, and CQDs with antibacterial and enhanced binding functions could also be prepared, proving that polycarboxylic acids are replaceable as carbon sources.

[0057] The CQDs / PEG wood strengthening agents in Examples 5-6 and Comparative Examples 2 and 4 were tested using method (2), and the results are as follows: Figure 11 As shown, the antifungal properties of the CQDs / PEG wood strengthening agents in Examples 5-6 and Comparative Examples 2 and 4 were tested using method (3), and the results are as follows. Figure 12 As shown, from Figure 11 and Figure 12It can be seen that in Example 5, after replacing the molecular weight of PEG with 4000, CQDs could be synthesized and a wood strengthening agent could be formulated. The antibacterial properties of the wood strengthening agent were maintained, and the strengthening characteristics could be adjusted according to the molecular weight. In Example 6, the concentration of the CQDs stock solution was adjusted to 300 ppm, which could prepare a wood strengthening agent with excellent antibacterial and strengthening properties. In Comparative Example 2, the concentration of the PEG 2000 solution was adjusted to 20 wt%, and its strengthening performance was significantly reduced; in Comparative Example 4, omitting PEG 2000 in the CQDs powder preparation process significantly reduced its strengthening performance.

[0058] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A wood strengthening agent, characterized in that, The components include the following concentrations: Carbon quantum dots 9~15ppm, polyethylene glycol 25~50wt%, balance solvent; The surface of the carbon quantum dots contains amino and carboxyl groups.

2. The wood strengthening agent according to claim 1, characterized in that, The molecular weight of the polyethylene glycol is 1000~4000.

3. The wood strengthening agent according to claim 1, characterized in that, The method for preparing the carbon quantum dots includes the following steps: Organic carbon source, organic nitrogen source, polyethylene glycol and water are mixed and microwaved to obtain the carbon quantum dots.

4. The wood strengthening agent according to claim 3, characterized in that, In the preparation of the carbon quantum dots, the molecular weight of the polyethylene glycol is 1000~4000; The organic carbon source is a polycarboxylic acid, which includes citric acid and / or malic acid; The organic nitrogen source includes one or more of urea and amino acids; The molar ratio of the organic nitrogen source to the organic carbon source is 4~35:1; The mass ratio of the organic carbon source to polyethylene glycol is 3:1; The mass ratio of the organic carbon source to water is 0.6:10mL.

5. The wood strengthening agent according to claim 3 or 4, characterized in that, The power of the microwave processing is 400~600W.

6. The wood strengthening agent according to claim 3, characterized in that, After the microwave treatment is completed, the process further includes: mixing the obtained char-like solid microwave treatment system with water, and then performing ultrasonic dispersion and centrifugation to remove insoluble matter and obtain a suspension; and then performing dialysis and freeze-drying on the suspension to obtain the carbon quantum dots.

7. The wood strengthening agent according to claim 6, characterized in that, The ultrasonic dispersion time is 10-30 min; the centrifugation speed is 9000-11000 rpm and the time is 4-6 min; the molecular weight cutoff of the dialysis bag used for dialysis is 400-600 Da and the dialysis time is 36-60 h; the freeze-drying temperature is -40℃ and the time is 36-60 h.

8. A method for preparing the wood strengthening agent according to any one of claims 1 to 7, characterized in that, Includes the following steps: Carbon quantum dots were dispersed in a portion of water to obtain a carbon quantum dot stock solution; Disperse polyethylene glycol in the remaining water to obtain a polyethylene glycol solution; The carbon quantum dot stock solution and the polyethylene glycol solution are mixed to obtain the wood strengthening agent.

9. The preparation method according to claim 8, characterized in that, The concentration of the carbon quantum dot stock solution is 240-360 ppm, and the concentration of the polyethylene glycol solution is 25-50 wt%.

10. The application of the wood consolidating agent according to any one of claims 1 to 7 or the wood consolidating agent prepared by the preparation method according to any one of claims 8 to 9 in the protection of wooden cultural relics.

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