A multifunctional nano-composite anti-weathering reinforcement material for masonry cultural relics and its preparation method

Abstract

The present invention discloses a multifunctional nano-composite anti-weathering reinforcement material for masonry cultural relics and its preparation method, which relates to the technical field of cultural relic protection materials. Using alkoxysilane, tetrapod-like zinc oxide and nano-silica as raw materials, after one-step mixing reaction in an organic solvent, a nano-composite material dispersion is obtained; the nano-composite material dispersion is evenly applied to the surface of masonry cultural relics by spraying or brushing method, and after the solvent is completely volatilized, an anti-weathering layer is formed on the surface of the masonry cultural relics. The nano-composite multifunctional material based on micro-nano ZnO, SiO2 and alkoxysilane is used for the anti-weathering protection of masonry cultural relics, endowing the masonry cultural relics with excellent hydrophobicity, antibacterial property and surface reinforcement effect, and having good durability to maintain long-term anti-weathering effect.

Description

Technical Field

[0001] The invention relates to the technical field of cultural relics protection materials, and in particular to a multifunctional masonry cultural relics nano-composite weathering-proof reinforcement material and a preparation method thereof. Background Art

[0002] Brick and stone cultural relics include cliff carvings, tomb carvings, cave statues and various types of brick and stone ancient buildings. They have high historical, artistic and scientific value. They are an important part of my country's historical and cultural heritage and a physical witness to my country's thousands of years of brilliant civilization. However, in the open air environment, brick and stone cultural relics have been subjected to physical, chemical and biological weathering caused by acid rain, atmospheric pollutants, microbial spores and other sedimentation for a long time, and the surface weathering is serious. Surface weathering phenomena (such as cracks, peeling, microbial reproduction, salt overflow, etc.) not only seriously endanger the stability of the cultural relics themselves, but also lead to the loss of historical information and artistic value contained in the cultural relics. Therefore, in view of the characteristics of the open air environment, in order to slow down the weathering of the surface of cultural relics and prevent the weathering from developing from the surface to the inside, it is very urgent to develop anti-weathering materials with excellent hydrophobicity, antibacterial properties and reinforcement effects.

[0003] At present, super-hydrophobic materials with excellent hydrophobicity and self-cleaning functions have great application potential in the weathering protection of open-air stone cultural relics. Their excellent performance can not only protect the cultural relics from water damage, but also maintain the surface artistic characteristics (Journal of Materials, 2020, 34: 3178-3184; J. Colloid Interface Sci., 2021, 591: 239-252; Construct. Build. Mater., 2022, 320: 126175). However, after preliminary application by domestic and foreign scholars, it was found that the existing super-hydrophobic materials cannot fully meet the actual application needs, such as the antibacterial property and durability of the materials still need to be further improved. Moreover, super-hydrophobic materials usually do not have reinforcement properties and cannot meet the needs of reshaping the cohesion of degraded stone materials and improving mechanical strength.

[0004] At present, my country also has some patents related to super-hydrophobic and anti-weathering materials for masonry cultural relics. The Chinese patent with patent number CN201010618653.8 discloses an inorganic-organic super-hydrophobic composite material for stone cultural relics and its preparation method. Nano ZnO / SiO2 particles with a mass fraction of 0.2-4% and a particle size of 20-200nm are dispersed in a hydrophobic organic silicon liquid phase and then applied to the surface of the stone to obtain a super-hydrophobic and anti-weathering layer. The preparation process of this method is complicated, and it is necessary to first prepare SiO2 nanoparticles, then coat ZnO on the surface of SiO2, and then use ball milling and ultrasonic dispersion to disperse the nanoparticles in an organic solution. In addition, the material does not show that it has photocatalytic antifouling and antibacterial effects, and its functions are relatively single.

[0005] The Chinese patent with the patent number CN202011208764.1 discloses a preparation method of a superhydrophobic composite material. First, nano-SiO2 is dispersed in an organic solvent to form a sol; then deionized water is added to the nano-SiO2 sol, and the pH value of the dispersion is adjusted to 3.5 - 4.5 with an organic acid; subsequently, isobutyltriethoxysiloxane is dispersed in the sol, and a composite sol is obtained after the hydrolysis of the siloxane. The preparation process of this method is relatively complex, and organic acids are introduced during the preparation of the sol. These acidic residues have a chemical corrosive effect on the stone cultural relics themselves, and do not meet the requirements of the physical and chemical compatibility of cultural relic protection materials.

[0006] The Chinese patent with the patent number CN201410027162.4 discloses a weathering-resistant material for stone cultural relics based on fluorosilicon polymers. Using modified tetraethyl orthosilicate sol as the core monomer and the copolymer of methyl methacrylate, n-butyl acrylate, acrylic acid, and dodecafluoroheptyl methacrylate as the shell monomer, a composite emulsion with a core-shell structure is formed after copolymerization reaction. This method requires a large variety of raw materials, the preparation process is complex, and the prepared weathering-resistant layer does not have the functions of anti-fouling and antibacterial, and the functions are relatively single.

[0007] The Chinese patent with the patent number CN202211148454.4 discloses a preparation method of a hydrophobic composite material for the protection of stone cultural relics. The preparation steps include: first, preparing a mixed solution of absolute ethanol and deionized water and adjusting the pH of the solution to 4 - 5; adding a fluorosilane coupling agent; then slowly adding UIO-66-(OH) n powder to the solution, heating and ultrasonicating; then drying and curing the product, grinding to obtain UIO-O-FS powder; finally, dispersing the product powder in a mixed solution of deionized water and an organic solvent, and ultrasonicating to obtain a hydrophobic composite material. The preparation process of this method is complex, and the prepared weathering-resistant layer does not have antibacterial and strengthening properties.

[0008] The technical solutions provided by the above-mentioned literature and patents solve some problems of the surface weathering protection of masonry cultural relics, but factors such as complex material preparation processes, single functions, and poor durability limit their large-scale application and promotion. Summary of the Invention

[0009] Aiming at the deficiencies in the above-mentioned background technology, the main problems of the present invention are that the single function, poor durability and complex preparation process of the existing weathering-resistant materials disclosed in the prior art limit their large-scale application and popularization. The present invention provides a multifunctional nano-composite weathering-resistant reinforcement material for masonry cultural relics, its preparation method and application. This weathering-resistant material is a nano-composite multifunctional material based on micro-nano ZnO, SiO2 and alkoxysilane, which is used for the weathering protection of masonry cultural relics, endowing the masonry cultural relics with excellent hydrophobicity, antibacterial property and surface reinforcement effect, and having good durability to maintain a long-term weathering-resistant effect. The method provided by the present invention solves the problems of complex preparation process, single performance, poor durability and other issues of the existing weathering-resistant materials for masonry cultural relics, which are not suitable for large-scale production and application.

[0010] The first object of the present invention is to provide a multifunctional nano-composite weathering-resistant reinforcement material for masonry cultural relics, which includes the following steps:

[0011] Using alkoxysilane, tetrapod-shaped zinc oxide and nano-silica as raw materials, after one-step mixing reaction in an organic solvent, a nano-composite material dispersion is obtained;

[0012] The nano-composite material dispersion is evenly applied to the surface of the masonry cultural relics by spraying or brushing. After the solvent is completely volatilized, a nano-composite weathering-resistant reinforcement layer is formed on the surface of the masonry cultural relics.

[0013] Preferably, during the acquisition of the nano-composite material dispersion, a certain amount of alkoxysilane is first evenly dispersed into an appropriate amount of organic solvent under magnetic stirring to obtain a sol; subsequently, according to the molar ratio of alkoxysilane, tetrapod-shaped zinc oxide and nano-silica of 3-2:1:1, tetrapod-shaped zinc oxide and nano-silica are respectively weighed, and under magnetic stirring, tetrapod-shaped zinc oxide and nano-silica are slowly added to the prepared sol at the same time, reacted at 35-45 °C for 20-40 minutes, and then ultrasonically dispersed for 10-20 minutes until it is uniform and without precipitation to obtain the nano-composite material dispersion.

[0014] Preferably, the whisker length of the tetrapod-shaped zinc oxide is 10-50 μm; the nano-silica is hydrophilic nano-silica with a particle size of 10-30 nm.

[0015] Preferably, the mass fraction of the alkoxysilane in the reaction solution is 1-10%.

[0016] Preferably, the alkoxysilane has the following structural formula:

[0017]

[0018] The second object of the present invention is to provide a multifunctional nano-composite weathering-resistant reinforcement layer for masonry cultural relics.

[0019] Preferably, the weathering-proof reinforcement layer has excellent hydrophobic performance, with a water contact angle of 160° to 168° and a rolling angle of 2.8° to 5.0°.

[0020] Preferably, the weathering-proof reinforcement layer has remarkable reinforcement performance, and the average mechanical strength of the surface layer of the stone substrate after weathering prevention treatment is increased by up to 20%.

[0021] Preferably, when the concentration of the nanocomposite material in the weathering-proof reinforcement layer is 0.2 - 1.5 g / L, the antibacterial efficiency against Gram-positive / negative bacteria reaches over 80% after being irradiated by a fluorescent lamp for 20 minutes and cultured for 6 hours.

[0022] Preferably, the weathering-proof reinforcement layer has excellent durability, outstanding mechanical abrasion resistance, chemical corrosion resistance and environmental weather resistance.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] (1) The preparation process of the nanocomposite multifunctional material of the present invention is simple, and the preparation is completed in one step by using the one-pot method; the cost of the required raw materials is moderate and environmentally friendly, and no fluorine-containing substances harmful to humans / biology and the environment, such as perfluoro and polyfluoroalkyl compounds, are used. When in use, the material dispersion can be coated on the surface of the masonry cultural relics by spraying or brushing methods to obtain a multifunctional weathering-proof layer with superhydrophobic, antibacterial and reinforcement properties. The whole process does not require heating / pressurization or special equipment, consumes less energy, and has application prospects in daily life and industrial production.

[0025] (2) The water contact angle of the weathering-proof layer formed by the nanocomposite multifunctional material of the present invention on the surface of the masonry cultural relics is 160° to 168°, and the rolling angle is 2.8° to 5.0°. At the same time, the weathering-proof layer also shows stable super anti-wetting properties to complex water dispersion systems, such as tea, coffee, milk, etc., strictly meeting the technical requirements of superhydrophobic and self-cleaning coatings.

[0026] (3) The nanocomposite multifunctional material of the present invention has high performance, and a small amount of usage can endow the weathering-proof layer with various functional characteristics. For masonry cultural relics with different porosities, the effective dosage of this material is not higher than 20 g / m 2 .

[0027] (4) The weathering-proof layer formed by the nanocomposite multifunctional material of the present invention has excellent capillary hydrophobic performance, and the capillary hydrophobic efficiency of different masonry substrates with a porosity of 2% - 45% is higher than 90% after being treated with this material.

[0028] (5) The nano-composite multifunctional material of the present invention has high-efficiency photocatalytic antibacterial properties. When the concentration is 0.2 - 1.5 g / L, after being irradiated by a fluorescent lamp for 20 minutes and cultured for 6 hours, the antibacterial efficiency against Gram-positive / negative bacteria reaches more than 80%. The antibacterial property of the anti-weathering layer comes from the tetrapod-shaped ZnO whiskers used. It is an n-type semiconductor with outstanding photocatalytic antibacterial properties, and the Zn particles themselves also have strong antibacterial effects.

[0029] (6) The anti-weathering layer prepared from the nano-composite multifunctional material of the present invention has remarkable reinforcement performance. After anti-weathering treatment, the average mechanical strength of the surface layer (0 - 10 mm) of the stone substrate is increased by 20%. The reinforcement performance of the anti-weathering layer comes from the synergistic effect of alkoxysilane [CH3(CH2)nCH2-Si(OR)3] and tetrapod-shaped ZnO. Alkoxysilane has 2 - 3 alkoxy groups and can generate polysiloxane (a considerable number of Si-O-Si bonds) through polycondensation reaction (sol-gelation) under appropriate conditions, that is, generate a silica gel network to connect each component inside the substrate, thereby playing a role in enhancing the mechanical strength of the substrate. At the same time, as an inorganic filler, the tetrapod-shaped microstructure of ZnO can be used as a skeleton to fill the silica gel network, having a reinforcing and toughening effect, and further enhancing the reinforcement effect of the anti-weathering layer.

[0030] (7) The anti-weathering layer formed by the nano-composite multifunctional material of the present invention does not change the original appearance characteristics and substrate air permeability of the masonry cultural relics. After anti-weathering treatment, the color change of the substrate surface is lower than the recognizable degree of the human eye (ΔE < 5), and the loss of the water vapor diffusion rate inside the substrate is < 10%, strictly meeting the requirements of cultural relic protection.

[0031] (8) The anti-weathering layer formed by the nano-composite multifunctional material of the present invention has excellent mechanical abrasion resistance and still maintains superhydrophobic and self-cleaning properties after being polished with sandpaper for 60 cycles; at the same time, it is chemically corrosion-resistant and shows stable super anti-wetting properties to solutions in the pH range of 3 - 14; in addition, it also has environmental weather resistance, and the anti-weathering effect does not weaken significantly after accelerated environmental aging, meeting the requirements for use in outdoor environments. The mechanical abrasion resistance, corrosion resistance, and weather resistance of the anti-weathering layer mainly come from the tetrapod-shaped ZnO whiskers used. The tetrapod-shaped ZnO whiskers are isotropic in three-dimensional scale, have high mechanical strength (close to the theoretical strength of pure single crystal), and are also chemically corrosion-resistant. Description of the Drawings

[0032] Figure 1 It is the electron microscope image of the tetrapod-shaped zinc oxide used in the present invention.

[0033] Figure 2 It is the self-cleaning performance test chart of the anti-weathering layer prepared in Example 1.

[0034] Figure 3Schematic diagrams of the microscopic morphology of the anti-weathering layer on the surface of the stone substrate in Example 1 and its surface water contact angle.

[0035] Figure 4 For the change in mechanical strength of the sample in Example 2 before and after anti-weathering treatment.

[0036] Figure 5 Schematic diagrams of the microscopic morphology of the anti-weathering layer on the surface of the stone substrate in Example 4 and its surface water contact angle. Detailed implementation manners

[0037] In order to enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and the accompanying drawings. However, the embodiments given are not intended to limit the present invention.

[0038] A multifunctional nano-composite anti-weathering and strengthening material for masonry cultural relics provided by the present invention has raw materials of nano-composite materials and solvents. Among them, the nano-composite material is prepared by reacting tetrapod-like zinc oxide whiskers (T-ZnO, whisker length 10 - 50 μm), hydrophilic nano-SiO2 (particle size 10 - 30 nm) and alkoxysilane. The specific preparation and usage methods are as follows.

[0039] The first aspect of the present invention provides a multifunctional nano-composite anti-weathering and strengthening material for masonry cultural relics, including the following steps:

[0040] Using alkoxysilane, tetrapod-like zinc oxide and nano-silica as raw materials, in an organic solvent, a nano-composite material dispersion is obtained through reaction;

[0041] The nano-composite material dispersion is evenly applied to the surface of the masonry cultural relic by spraying or brushing. After the solvent completely volatilizes, an anti-weathering and strengthening layer is formed on the surface of the masonry cultural relic.

[0042] Among them, the molar ratio of the alkoxysilane, tetrapod-like zinc oxide and nano-silica is 3 - 2:1:1. The whisker length of the tetrapod-like zinc oxide is 10 - 50 μm; the nano-silica is hydrophilic nano-silica with a particle size of 10 - 30 nm. The mass fraction of the alkoxysilane in the reaction solution is 1 - 10%. The morphology of the tetrapod-like zinc oxide is as Figure 1 shown.

[0043] The alkoxysilane has the following structural formula:

[0044]

[0045] In the formula, R is methyl or ethyl.

[0046] It should be noted that the reaction raw material alkoxysilane can be an alkoxysilane with R being methyl, or an alkoxysilane with R being ethyl, or a mixture of an alkoxysilane with R being methyl and an alkoxysilane with R being ethyl.

[0047] According to the present invention, during the reaction process, a certain amount of alkoxysilane is first evenly dispersed in an appropriate amount of organic solvent under magnetic stirring for 5 - 10 minutes, and then tetrapod-shaped zinc oxide and nano-silica are simultaneously added thereto under magnetic stirring, and the reaction is carried out at 35 - 45 °C for 20 - 40 minutes, and then ultrasonically dispersed for 10 - 20 minutes until it is uniform and without precipitation, obtaining a nano-composite material dispersion liquid. Among them, the organic solvent is absolute ethanol.

[0048] The second aspect of the present invention provides a multifunctional nano-composite anti-weathering reinforcement layer for masonry cultural relics.

[0049] Among them, the anti-weathering reinforcement layer has excellent hydrophobic performance, with a water contact angle of 160° - 168° and a rolling angle of 2.8° - 5.0°. The reinforcement performance of the anti-weathering reinforcement layer is remarkable, and the average mechanical strength of the surface layer of the stone substrate after anti-weathering treatment is increased by up to 20%. When the concentration of the nano-composite material in the anti-weathering reinforcement layer is 0.2 - 1.5 g / L, the antibacterial efficiency against Gram-positive / negative bacteria reaches more than 80% after being irradiated by a fluorescent lamp for 20 minutes and cultured for 6 hours. The durability of the anti-weathering reinforcement layer is excellent, and its mechanical abrasion resistance, chemical corrosion resistance and environmental weather resistance are outstanding.

[0050] The third aspect of the present invention provides an application of the multifunctional nano-composite anti-weathering reinforcement layer for masonry cultural relics in protecting open-air masonry cultural relics. During the application process, the capillary hydrophobic efficiency after preparing the anti-weathering layer on different masonry substrates with a porosity of 2% - 45% is higher than 90%.

[0051] It should be noted that the experimental methods adopted in the present invention are all conventional methods without special instructions; the reagents and materials adopted, without special instructions, can all be purchased in the market.

[0052] Example 1

[0053] Step 1, Preparation of nano-composite material

[0054] At room temperature, 0.34 ml of trimethoxy(octyl)silane is measured and evenly dispersed in 62.7 ml of absolute ethanol under magnetic stirring (for 5 minutes) to prepare a sol; according to the molar ratio of alkoxysilane / T-ZnO / nano-SiO2 = 3 / 1 / 1, 0.1 g of T-ZnO and 0.1 g of nano-SiO2 are respectively weighed, and the two are simultaneously and slowly added to the sol under magnetic stirring and heated for 30 minutes (40 °C), and then ultrasonically dispersed for 15 minutes until it is uniform and without precipitation, that is, a nano-composite material ethanol dispersion liquid with a mass fraction of 1% is prepared.

[0055] Step 2, preparation of a multifunctional weathering-resistant layer

[0056] Measure 4.7 ml of the dispersion in Step 1 (i.e., the actual effective dosage of the material is 15 g / m 2 ), and uniformly brush it on the surface of a gray limestone (calcite limestone, porosity ~5%) with a surface area of 5×5 square centimeters by the brushing method. After the solvent has completely volatilized, a multifunctional weathering-resistant layer is obtained.

[0057] Test the hydrophobic property of the weathering-resistant layer. The results show that its water contact angle is 164°±2.4°, the rolling angle is 3.0°, and the self-cleaning test also indicates that the coating has excellent self-cleaning performance ( Figure 2 ). Use a scanning electron microscope to characterize the surface microtopography of the weathering-resistant layer. The surface of the weathering-resistant layer is rough, and a large amount of nano-SiO2 adheres to the surface of the tetrapod-shaped ZnO, forming a micro-nano scale multi-level rough structure ( Figure 3 ). According to EU standards, test the capillary hydrophobic property, air permeability, and surface color and other indicators of the weathering-resistant layer. The results show that the weathering-resistant layer can effectively inhibit the penetration of capillary water (the hydrophobic efficiency in 4 hours is 92%), while maintaining the original air permeability of the substrate (the loss of water vapor diffusion rate is 6%) and the surface color (ΔE * <4). Use the OD 600 method to test the antibacterial property of the weathering-resistant material after 20 minutes of irradiation by a fluorescent lamp. The results show that the material can effectively inhibit the reproduction of Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria. When its concentration is 1.5 g / L, the antibacterial efficiencies against the two bacteria are 82% and 85% respectively. Use corrosive liquids (pH = 3 acetic acid solution, pH = 14 potassium hydroxide solution, etc.) to test the corrosion resistance of the weathering-resistant layer. The results show that the weathering-resistant layer has excellent corrosion resistance and can stably maintain its superhydrophobic property. In addition, use the sandpaper grinding method to test the abrasion resistance of the weathering-resistant layer. The results show that the weathering-resistant layer has excellent abrasion resistance, and it still maintains superhydrophobic and self-cleaning properties (water contact angle > 155° and rolling angle < 8°) after being ground with 1000-mesh sandpaper for 60 cycles.

[0058] Example 2

[0059] Step 1, preparation of a nanocomposite

[0060] At room temperature, 0.23 ml of trimethoxy(octadecyl)silane was measured and uniformly dispersed into 50.2 ml of absolute ethanol under magnetic stirring (for 5 minutes) to prepare a sol; according to the molar ratio of alkoxysilane / T-ZnO / nano-SiO2 = 2 / 1 / 1, 0.1 g of T-ZnO and 0.1 g of nano-SiO2 were respectively weighed, and the two were slowly added to the sol simultaneously under magnetic stirring and heated for 30 minutes (40 °C), and then ultrasonically dispersed for 15 minutes until uniform and without precipitation, thus obtaining an ethanol dispersion of the nanocomposite with a mass fraction of 1%.

[0061] Step 2, prepare a multifunctional anti-weathering layer

[0062] Measure 4.7 ml of the dispersion in Step 1 (i.e., the effective dosage of the material is 15 g / m 2 ), and uniformly brush it on the surface of a blue-gray limestone (calcite limestone, porosity ~ 5%) with a surface area of 5 × 5 square centimeters by the brushing method. After the solvent has completely volatilized, a multifunctional anti-weathering layer is obtained.

[0063] The water contact angle of the prepared anti-weathering layer is 162.3° ± 2.8°, and the rolling angle is 3.6°, having superhydrophobic and self-cleaning properties. The anti-weathering layer also has excellent capillary hydrophobic properties, and its capillary hydrophobic efficiency reaches more than 90% within 4 hours, and the anti-weathering layer also does not significantly change the air permeability (the loss of water vapor diffusion rate is 5%) and surface color (ΔE * < 4) of the stone substrate. The reinforcement performance of the anti-weathering layer was tested by the micro-drilling method, and the results showed that the average mechanical strength of the surface layer (0 - 10 mm) of the sample after anti-weathering treatment was increased by about 21%( Figure 4 ). The mechanical wear test also showed that the anti-weathering layer has wear resistance, and the surface still maintains superhydrophobic and self-cleaning properties after 60 grinding cycles. In addition, the artificial climate chamber was used to accelerate the simulation of conditions such as temperature, humidity, and ultraviolet radiation in the open-air environment, and the performance changes of the anti-weathering layer were tested after 90 days of aging. The test results showed that the anti-weathering layer has high environmental weather resistance, still maintains superhydrophobic, self-cleaning properties and high capillary hydrophobic efficiency after 90 days of aging, and the surface color has no visible change to the naked eye.

[0064] Example 3

[0065] In this example, Step 1 is the same as in Example 1.

[0066] Step 2, prepare a multifunctional anti-weathering layer

[0067] Measure 3.13 ml of the dispersion in Step 3 (i.e., the effective dosage of the material is 10 g / m 2) It was evenly brush-coated on the surface of off-white marble (calcite marble, porosity ~2%) with a surface area of 5×5 square centimeters by the brush-coating method, and a multifunctional anti-weathering layer was obtained after the solvent completely volatilized.

[0068] The prepared anti-weathering layer also has superhydrophobic and self-cleaning properties. Its water contact angle is 160.3°±2.1°, and the rolling angle is 4.5°. Capillary hydrophobicity tests show that the anti-weathering layer has a high capillary hydrophobicity efficiency (capillary hydrophobicity efficiency >90% within 24 hours), and it does not significantly change the air permeability and original appearance of the stone substrate. OD 600 Antibacterial tests by the OD method show that this anti-weathering material can effectively inhibit the reproduction of Escherichia coli and Staphylococcus aureus. The results of micro-drilling tests also show that the anti-weathering layer has strong reinforcement properties.

[0069] Example 4

[0070] Step 1, Preparation of nano-composite material

[0071] At room temperature, 0.34 ml of trimethoxy(octyl)silane was measured and evenly dispersed into 50.2 ml of absolute ethanol under magnetic stirring (for 5 minutes) to prepare a sol; 0.1 g of T-ZnO was weighed according to the molar ratio of alkoxysilane / T-ZnO = 3 / 1, and it was slowly added to the sol under magnetic stirring and heated for 30 minutes (40 °C), and then ultrasonically dispersed for 15 minutes until it was uniform and without precipitation, thus obtaining a 1% by mass nano-composite material ethanol dispersion.

[0072] Step 2, Preparation of anti-weathering layer

[0073] 4.7 ml of the dispersion liquid from Step 1 was measured (i.e., the effective dosage of the material is 15 g / m 2 ), and it was evenly brush-coated on the surface of bluish-gray limestone (calcite limestone, porosity ~5%) with a surface area of 5×5 square centimeters by the brush-coating method, and an anti-weathering layer was obtained after the solvent completely volatilized.

[0074] Water contact angle tests show that the surface of the prepared anti-weathering layer is hydrophilic, and the water contact angle is 70°±4.5°. Capillary hydrophobicity tests also show that the anti-weathering layer does not have capillary hydrophobicity. Surface color tests found that the stone substrate became significantly white, and the surface color change value ΔE * = 6.3. Using scanning electron microscopy to characterize its surface morphology, it was found that there is no micro-nano multi-level rough structure on the surface of the anti-weathering layer, and there are only micron-sized T-ZnO attachments ( Figure 5 ). This example shows that only using micron-sized T-ZnO and alkoxysilane as raw materials cannot form a micro-nano multi-level rough structure on the surface of the stone substrate, and does not meet the microscopic structure requirements for preparing a superhydrophobic coating.

[0075] Example 5

[0076] Step 1, Preparation of Nanocomposite Materials

[0077] At room temperature, 0.34 ml of trimethoxy (octyl) silane was measured and evenly dispersed in 50.2 ml of anhydrous ethanol under magnetic stirring (5 minutes) to prepare a sol; at a molar ratio of alkoxysilane / SiO2 = 3 / 1, 0.1 g of nano-SiO2 was weighed and slowly added into the sol under magnetic stirring and heated for 30 minutes (40°C), followed by ultrasonic dispersion for 15 minutes until uniform and precipitate-free, thereby obtaining a nano-composite alcohol dispersion with a mass fraction of 1%.

[0078] Step 2: Prepare the weathering protection layer

[0079] Measure 4.7 ml of the dispersion in step 1 (i.e., the effective amount of material is 15 g / m 2 ), and evenly apply it on the surface of blue-gray limestone (calcite limestone, porosity ~5%) with a surface area of ​​5×5 square centimeters by brushing, and the anti-weathering layer is obtained after the solvent is completely evaporated.

[0080] The water contact angle test shows that the weathering-proof layer has super hydrophobicity and self-cleaning function, and its surface water contact angle is 156.5°±2.9° and the rolling angle is 6.8°. The capillary hydrophobicity test shows that the weathering-proof layer has good capillary hydrophobicity, and its hydrophobic efficiency is 85% within 4 hours. OD 600 The antibacterial test of the method shows that the anti-weathering material has no antibacterial properties and cannot inhibit the reproduction of Escherichia coli and Staphylococcus aureus. After 20 cycles of polishing the surface of the anti-weathering layer with 1000 mesh sandpaper, the anti-weathering layer has lost its original super-hydrophobic and self-cleaning properties, and its surface water contact angle is only 100.3 ° ± 4.2 °. This embodiment illustrates that a super-hydrophobic coating can be prepared using only alkoxysilane and nano-SiO2 as raw materials, but the obtained coating does not have antibacterial properties and is not resistant to mechanical wear.

[0081] Example 6

[0082] Step 1, material preparation

[0083] In this embodiment, the weatherproof material is prepared without using T-ZnO or nano-SiO2. 0.34 ml of trimethoxy (octyl) silane is measured and evenly dispersed in 37.7 ml of anhydrous ethanol under magnetic stirring (5 minutes) to prepare a sol, that is, a dispersion liquid with a mass fraction of 1% is prepared.

[0084] Step 2: Prepare the weathering protection layer

[0085] Measure 4.7 ml of the dispersion in step 1 (i.e., the effective amount of material is 15 g / m 2) It was evenly brush-coated on the surface of blue-grey limestone (calcite limestone, porosity ~5%) with a surface area of 5×5 square centimeters by the brush-coating method, and a weathering-resistant layer was obtained after the solvent completely volatilized.

[0086] Water contact angle tests showed that the water contact angle on the surface of the prepared weathering-resistant layer was 96.5°±3.4°, and it did not have superhydrophobic and self-cleaning functions. Capillary hydrophobicity tests showed that the capillary hydrophobic effect of the weathering-resistant layer was poor, and its hydrophobic efficiency was less than 50% within 4 hours. Scanning electron microscopy was used to characterize its surface morphology and found that there was no micro-nano multi-level rough structure on the surface of the weathering-resistant layer. OD 600 The antibacterial test results by the OD method also showed that this weathering-resistant material had no antibacterial properties. The test results by the micro-drilling method showed that the strengthening effect of this weathering-resistant layer was limited, and it only had a certain effect on the outermost layer (0-1.5 mm) of the substrate. This example shows that only using hydrophobic alkoxysilane cannot prepare a multifunctional superhydrophobic weathering-resistant layer on the surface of a stone substrate.

[0087] Example 7

[0088] Step 1, Preparation of the nanocomposite

[0089] In this example, Step 1 was the same as in Example 1, but T-ZnO was replaced with spherical ZnO with the same mass and a particle size of 50 nanometers.

[0090] Step 2, Preparation of the multifunctional weathering-resistant layer

[0091] Measure 4.7 ml of the dispersion liquid from Step 1 (i.e., the actual effective dosage of the material is 15 g / m 2 ) It was evenly brush-coated on the surface of blue-grey limestone (calcite limestone, porosity ~5%) with a surface area of 5×5 square centimeters by the brush-coating method, and a multifunctional weathering-resistant layer was obtained after the solvent completely volatilized.

[0092] The hydrophobic property of the weathering-resistant layer was tested, and the results showed that its water contact angle was 152° ± 4.6°, and the rolling angle was 8.6°, indicating superhydrophobic property. However, its hydrophobic property was lower than that of Example 1 (with a lower water contact angle and a higher rolling angle). The abrasion resistance of the weathering-resistant layer was tested by the sandpaper grinding method. After grinding with 1000-mesh sandpaper for 20 cycles, the weathering-resistant layer lost its superhydrophobic property and self-cleaning property, its water contact angle decreased to ~138°, and water droplets adhered to the surface and could not roll. The reinforcement performance of the weathering-resistant layer was tested by the micro-drilling method, and the results showed that the reinforcement effect of the weathering-resistant layer was not significant, and the mechanical strength was only increased by about 8% in the outermost layer (0 - 2 mm). This example shows that a superhydrophobic coating can be prepared using spherical nano-ZnO as the raw material, but the obtained coating does not have mechanical abrasion resistance. The main reason is that spherical nano-ZnO does not have the microscopic three-dimensional structure of T-ZnO, is not wear-resistant and corrosion-resistant, resulting in poor durability of the weathering-resistant layer. At the same time, spherical nano-ZnO does not have the microscopic three-dimensional structure of tetrapod-like ZnO and does not have the functions of a skeleton and toughening reinforcement, so it cannot improve the reinforcement performance of the weathering-resistant layer.

[0093] Example 8

[0094] Step 1, Preparation of the nanocomposite material

[0095] In this example, Step 1 was the same as that in Example 1, but T-ZnO was replaced with flaky ZnO with the same mass and a particle size of 2 - 3 microns.

[0096] Measure 4.7 ml of the dispersion liquid in Step 1 (i.e., the actual effective amount of the material is 15 g / m 2 ), and evenly brush it on the surface of a blue-gray limestone (calcite limestone, porosity ~5%) with a surface area of 5 × 5 square centimeters by the brushing method. After the solvent has completely evaporated, a multifunctional weathering-resistant layer is obtained.

[0097] The hydrophobic property of the weathering-resistant layer was tested, and the results showed that its water contact angle was 158° ± 3.0°, and the rolling angle was 7.0°, indicating superhydrophobic property. However, its hydrophobic property was lower than that of Example 1. The abrasion resistance of the weathering-resistant layer was tested by the sandpaper grinding method. When grinding with 1000-mesh sandpaper for 30 cycles, the weathering-resistant layer lost its superhydrophobic property and self-cleaning property, because its water contact angle decreased to ~140°, and water droplets adhered to the surface and could not roll. The reinforcement performance of the weathering-resistant layer was tested by the micro-drilling method, and the results showed that the reinforcement effect of the weathering-resistant layer was not significant, and the mechanical strength was only increased by about 10% in the outermost layer (0 - 3 mm). This example shows that flaky nano-ZnO does not have the tetrapod-like microscopic three-dimensional structure of T-ZnO and is not resistant to mechanical wear, so the durability of the weathering-resistant layer is poor. At the same time, flaky nano-ZnO also does not have the functions of a skeleton and toughening reinforcement of tetrapod-like ZnO and cannot improve the reinforcement performance of the weathering-resistant layer.

[0098] The above eight embodiments do not represent the limited scope of application of this patent. For masonry cultural relics with different materials, areas, and degrees of deterioration, the use concentration, volume, dosage, etc. of the anti-weathering material can be flexibly adjusted to achieve the best superhydrophobic, anti-fouling, and antibacterial effects.

[0099] This invention describes the preferred embodiments and their effects. However, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications falling within the scope of this invention.

[0100] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A preparation method of a multifunctional nano composite anti-weathering reinforcement material for masonry cultural relics, characterized in that, It includes the following steps: Using alkoxysilane, tetrapod-like zinc oxide and nano-silica as raw materials, after one-step mixing reaction in an organic solvent, a nano-composite material dispersion liquid is obtained; The nano-composite material dispersion liquid is evenly applied to the surface of masonry cultural relics by spraying or brushing method. After the solvent is completely volatilized, a weathering-proof and strengthening layer is prepared on the surface of the masonry cultural relics; The alkoxysilane has the following structural formula: In the formula, R is methyl or ethyl.

2. The preparation method of the multifunctional nano composite anti-weathering reinforcement material for masonry cultural relics according to claim 1, characterized in that During the acquisition of the nano-composite material dispersion liquid, a certain amount of alkoxysilane is first evenly dispersed into an appropriate amount of organic solvent under magnetic stirring to obtain a sol; then, according to the molar ratio of alkoxysilane, tetrapod-like zinc oxide and nano-silica of 3-2:1:1, the tetrapod-like zinc oxide and nano-silica are respectively weighed, and the tetrapod-like zinc oxide and nano-silica are slowly added to the prepared sol at the same time under magnetic stirring, reacted at 35-45 °C for 20-40 minutes, and then ultrasonically dispersed for 10-20 minutes until it is uniform and without precipitation to obtain the nano-composite material dispersion liquid.

3. The preparation method of the multifunctional nano composite anti-weathering reinforcement material for masonry cultural relics according to claim 1, characterized in that The whiskers of the tetrapod-like zinc oxide are 10-50 μm long; the nano-silica is hydrophilic nano-silica with a particle size of 10-30 nm.

4. The preparation method of the multifunctional nano composite anti-weathering reinforcement material for masonry cultural relics according to claim 1, characterized in that, The mass fraction of the alkoxysilane in the reaction solution is 1-10%.

5. A multifunctional nano-composite weathering-proof and strengthening layer for masonry cultural relics prepared by the method according to any one of claims 1 to 4.

6. The multifunctional nano-composite anti-weathering reinforcement layer for masonry cultural relics according to claim 5, wherein, The weathering-proof and strengthening layer has excellent hydrophobic performance, with a water contact angle of 160° to 168° and a rolling angle of 2.8° to 5.0°.

7. The multifunctional nano-composite anti-weathering reinforcement layer for masonry cultural relics according to claim 5, wherein The strengthening performance of the weathering-proof and strengthening layer is remarkable, and the average mechanical strength of the surface layer of the stone substrate is increased by 20% after weathering-proof treatment.

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