阅读说明：本技术 细菌纤维素基碱性纳米粒子的多功能纸张修复液的制备方法及其在老化纸张修复中的应用 (Preparation method of multifunctional paper repair liquid containing bacterial cellulose-based alkaline nanoparticles and application of multifunctional paper repair liquid in aged paper repair ) 是由 牟洪燕 吴潇 樊慧明 于 2021-08-20 设计创作，主要内容包括：本发明公开了细菌纤维素基碱性纳米粒子的多功能纸张修复液的制备方法及其在老化纸张修复中的应用。该方法将碱性纳米粒子加入到细菌纤维素基材料中,实现碱性纳米粒子的良好分散,然后通过浸泡、涂布、喷涂、雾化等多种方法将细菌纤维素和碱性纳米粒子负载到纸张上,对纸张进行脱酸、增强与抗菌处理,提高纸张的力学强度、pH值、碱储量以及使用耐久性,并赋予纸张一定的抗菌性能。所述细菌纤维素是由细菌微生物分泌合成的纤维素或改性细菌纤维素。本发明的一种细菌纤维素基碱性纳米粒子的多功能纸张修复液及对纸张的处理方法实现了碱性纳米粒子的有效分散和老化纸张的一步脱酸、增强和抗菌。(The invention discloses a preparation method of a multifunctional paper repair liquid of bacterial cellulose-based alkaline nanoparticles and application of the multifunctional paper repair liquid in aged paper repair. According to the method, alkaline nanoparticles are added into a bacterial cellulose-based material to achieve good dispersion of the alkaline nanoparticles, then bacterial cellulose and the alkaline nanoparticles are loaded on paper by various methods such as soaking, coating, spraying and atomizing, deacidification, enhancement and antibacterial treatment are carried out on the paper, the mechanical strength, the pH value, the alkali storage capacity and the use durability of the paper are improved, and the paper is endowed with a certain antibacterial property. The bacterial cellulose is cellulose secreted and synthesized by bacterial microorganisms or modified bacterial cellulose. The multifunctional paper repair liquid containing bacterial cellulose-based alkaline nanoparticles and the paper treatment method realize effective dispersion of the alkaline nanoparticles and one-step deacidification, reinforcement and antibiosis of aged paper.)

1. The preparation method of the multifunctional paper repair liquid containing bacterial cellulose-based alkaline nanoparticles is characterized by comprising the following steps of:

(1) crushing bacterial cellulose or modified bacterial cellulose-based material, and carrying out high-pressure homogenization in high-pressure micro-jet nano-dispersion equipment to obtain the bacterial cellulose-based material;

(2) dispersing alkaline inorganic nanoparticles in water, ethanol, isopropanol or HMDO solution, uniformly mixing, adding the bacterial cellulose-based material, stirring at room temperature, and performing ultrasonic dispersion treatment to obtain the multifunctional paper repair liquid of the bacterial cellulose-based alkaline nanoparticles;

(3) loading the multifunctional paper repair liquid of the bacterial cellulose base alkaline nanoparticles on ancient book paper, and performing deacidification, reinforcement and antibacterial treatment on the ancient book paper.

2. The method for preparing the multifunctional paper repair liquid containing bacterial cellulose-based alkaline nanoparticles as claimed in claim 1, wherein in the step (1), the bacterial cellulose is directly secreted and synthesized by microorganisms; the modified bacterial cellulose is etherified, aminated, quaternized and silanized modified bacterial cellulose obtained by adopting special bacterial culture solution for culture or being modified by chemical reagents.

3. The method for preparing the multifunctional paper restoration solution containing bacterial cellulose based alkaline nanoparticles according to claim 2, wherein the culture conditions of the microorganisms are static or dynamic fermentation culture conditions; the microorganism is one of gluconacetobacter, acetobacter, agrobacterium, pseudomonas, achromobacter, alcaligenes, aerobacter, azotobacter, rhizobium and sarcina; the special bacteria culture solution comprises a culture solution added with at least one of hydroxylamine hydrochloride, polyacrylamide, polyethyleneimine and ammonia water.

4. The preparation method of the multifunctional paper repair liquid containing bacterial cellulose-based alkaline nanoparticles according to claim 2, wherein the bacterial cellulose is modified by etherification, the bacterial cellulose is soaked in sodium hydroxide to obtain the alkaline cellulose, and then the alkaline cellulose is subjected to Williamson etherification or Michael addition reaction with an alkyl compound, an alkoxy compound and a vinyl compound, wherein the alkyl compound, the alkoxy compound and the vinyl compound are one of methyl chloride, ethyl chloride, sulfonyl ethane, ethylene oxide and acrylonitrile; the method for aminating and modifying the bacterial cellulose comprises the steps of bonding a nitrogen-containing compound with hydroxyl of the bacterial cellulose, and grafting a nitrogen-containing group, wherein the nitrogen-containing compound is one of hydroxylamine hydrochloride, acrylamide, ethylenediamine, diethylamine, tetraethylenepentamine, dimethylamine and N-methylimidazole; the method for quaternizing the modified bacterial cellulose comprises the steps of swelling the bacterial cellulose by using sodium hydroxide, and then performing quaternization reaction on alkyl quaternary ammonium salt or organosilicon quaternary ammonium salt and the bacterial cellulose to connect a quaternary ammonium salt group, wherein the quaternary ammonium salt is one of dodecyl triphenyl ammonium chloride, dimethyl diallyl ammonium chloride, (3-chloro-2-hydroxypropyl) trimethyl ammonium chloride, epoxypropyl trimethyl ammonium chloride and (trimethoxysilylpropyl) octadecyl dimethyl ammonium chloride; the silanization modified bacterial cellulose is prepared by adopting a chemical vapor deposition method or reacting in a water/ethanol/isopropanol system, and introducing silane groups on the surface of the bacterial cellulose through silanization reaction with a silanization reagent, wherein the silanization reagent is one of aminopropyltriethoxysilane, hexadecyltrimethoxysilane, dimethyldichlorosilane, trimethylchlorosilane, diethylaminomethyltriethoxysilane, 3- (2, 3 epoxypropoxy) propylmethyldimethoxysilane and vinyltriethoxysilane.

5. The method for preparing the multifunctional paper restoration solution containing bacterial cellulose based alkaline nanoparticles according to claim 1, wherein in the step (1), the high-pressure homogenization pressure is 30-90bar, and the treatment times are 1-10 times.

6. The method for preparing the multifunctional paper repair liquid containing bacterial cellulose-based alkaline nanoparticles according to claim 1, comprising the following steps(2) The basic inorganic nanoparticles MgO, Ca (OH)₂、TiO₂、ZnO、Mg(OH)₂、CaCO₃One or more of (1); the mass volume ratio of the alkaline inorganic nanoparticles to water, ethanol, isopropanol or HMDO solution is 1-6g/L, wherein the water accounts for 0-80 wt%, the ethanol accounts for 0-80 wt%, the isopropanol accounts for 0-20 wt%, and the HMDO accounts for 0-80 wt%; in the multifunctional paper repair liquid containing bacterial cellulose-based alkaline nanoparticles, the concentration of a bacterial cellulose-based material is 0.4-1.4 wt%, and the concentration of alkaline nanoparticles is 0.2-1.0 wt%; the ultrasonic power of the ultrasonic dispersion treatment is 200-900W, and the time of the ultrasonic dispersion treatment is 20-80 min.

7. The method for preparing the multifunctional paper repairing solution containing bacterial cellulose-based alkaline nanoparticles according to claim 1, wherein in the step (3), the multifunctional paper repairing solution containing bacterial cellulose-based alkaline nanoparticles is loaded on ancient paper, and comprises the following steps of: after the aged paper is subjected to constant temperature and humidity treatment, wherein the constant temperature and humidity treatment conditions are that the temperature is 23 +/-1 ℃, the humidity is 50 +/-2%, the treatment time is 24 hours, and the aged paper is subjected to vacuum drying treatment, wherein the drying treatment conditions are that the vacuum degree is 0.6bar, the temperature is 35 +/-1 ℃, and the treatment time is 6 hours, so that the aged paper after drying treatment is obtained; then treating the paper with the multifunctional paper repair liquid containing the bacterial cellulose-based alkaline nanoparticles, and then placing the paper in a fume hood for air drying treatment to obtain treated aged paper; and drying the treated aged paper, then carrying out constant temperature and humidity treatment, and taking out to finish the restoration treatment of the aged paper.

8. The preparation method of the multifunctional paper repairing solution containing bacterial cellulose-based alkaline nanoparticles according to claim 1, wherein the repairing treatment method of the aged paper by the multifunctional paper repairing solution containing bacterial cellulose-based alkaline nanoparticles is a soaking method, a coating method, a spraying method or an atomization method, wherein the soaking method is to soak the aged paper into the repairing solution which is uniformly dispersed; the coating method is that the repair liquid is uniformly coated, spin-coated or brush-coated on the aged paper by an automatic coating machine, a coating rod or a coating brush; the spraying method is that the aged paper is put on a smooth and clean glass plate and is sprayed by a high-pressure spray can; the atomization method is that the aged paper is placed in a closed device, and then the repairing liquid is treated by ultrasonic atomization or pressure atomization and then is introduced into the closed device.

9. The multifunctional paper repair liquid of bacterial cellulose-based alkaline nanoparticles prepared by the preparation method of any one of claims 1 to 8.

10. The multifunctional paper restoration solution of bacterial cellulose based alkaline nanoparticles as claimed in claim 9 is applied to one-step deacidification, reinforcement and antibiosis of aged paper.

Technical Field

The invention relates to the technical field of ancient book protection, in particular to a multifunctional paper repairing liquid of bacterial cellulose-based basic nanoparticles, a preparation method of the multifunctional paper repairing liquid and application of the multifunctional paper repairing liquid in aged paper repairing.

Background

Ancient books are important historical carriers of development and progress of human material culture and spiritual culture all over the world, and are very important and irreproducible cultural relics. As one of four civilized ancient countries, the number of the existing paper cultural relics in China is huge, and according to incomplete statistics, about 20 thousands of existing paper literature are available, and 5000 thousands of books exist. In 2002-2005, the national cultural relics administration organizes a survey of the corrosion damage condition of the cultural relics in the collection, and finds that 50.66% of the cultural relics in the collection have corrosion conditions of different degrees, and paper is saturated with problems such as oxidation, acidification, aging and the like (Zhang jin Ling and Keng Xiong, 2011). Paper is a cellulose-based carrier structure containing small amounts of hemicellulose and lignin. Over time, hemicellulose and lignin are oxidized and hydrolyzed to form acidic species, which cause hydrolysis of cellulose in the paper, resulting in a decrease in the degree of polymerization of cellulose. Residual lignin in paper is easy to be oxidized and hydrolyzed to generate acidic substances and chromophoric groups; trace chloride remained in the processes of acid pulping and bleaching accelerates the deterioration of paper; paper making processThe added acidic chemicals such as acidic alum, acidic rosin and the like are hydrolyzed to generate acidic substances; inks and pigments, etc. that use acid or oxygenated chemicals during printing are also acidic, further exacerbating the acidification of the paper. In addition, the paper is influenced by external environment during storage, such as gnawing of small animals, and harmful gas (such as SO) in atmosphere₂NOx, etc.) and microorganisms (metabolically produced organic acids), which can cause acidification, yellowing, and strength reduction in paper (bat et al, 2010). The paper acidification is caused by a plurality of factors which are interactive and mutually promoted, and once the paper literature has an embrittlement problem, the paper literature cannot provide a normal page turning function, and is often difficult to carry out protection measures such as dust removal, deacidification and restoration, so that the long-term storage of the paper literature is not facilitated. Therefore, there is a need for protection and repair of paper literature.

Conventional paper deacidification uses aqueous alkaline solutions to impregnate aged paper, mainly aqueous, organic and gas phase deacidification processes, focusing mainly on the study and application of dispersions of magnesium, calcium salts and amine-based alkaline agents (Bluher and vogelseger, 2001). However, these methods have problems such as complicated process, powder deposition, ink blurring, safety problems, etc. With the development of nanotechnology, nano magnesium oxide, nano calcium carbonate and the like are also applied to the paper deacidification field (Bastone et al, 2017; Poggi et al, 2014; WLo Jociak, 2016), but nanoparticles are easy to agglomerate due to large specific surface area and surface energy, and the research of a good dispersion system is also very important. The paper strengthening field mainly adopts natural high molecular materials (cellulose, cellulose ether, nano-cellulose, guar gum, artemisia glue, chitosan, starch and the like), organic synthetic high molecular materials (polyvinyl alcohol, polyacrylamide, polyurethane, emulsion) and some organic synthetic materials (aminosilane, alkoxy silane and the like) (Li et al, 2019). However, the stability and aging resistance of these reinforcing agents themselves have a far-reaching influence on the paper reinforcing effect, and among them, the cellulose-based natural polymer compounds having high strength and stability are widely concerned. Panchen treated with 1.0% sodium carboxymethylcellulose increased the folding resistance by 10 times, tear strength by 50%, and tensile strength by more than 95.5%, but the reinforcing agent adversely affected the ink writing on the paper (Panchen, 2019). The nano-cellulose as a nano-scale cellulose aggregate has the characteristics of high crystallinity, high Young modulus, high strength and the like, and also has the characteristics of structure similar to plant fiber, good biocompatibility, degradability, no toxicity, reproducibility and the like. The nano-cellulose is more and more concerned as a green reinforced material, and has great application prospect in preparing high-performance nano-composite materials. And a large amount of hydroxyl exists on the surface of the nano-cellulose, so that a strong hydrogen bond effect can be formed with fiber hydroxyl in paper, the bonding force between fibers is increased, and the physical strength of the paper is improved. Ma et al repaired aged paper by (nanocellulose microcrystalline) CNC spraying sulfuric acid process, tear index increased by 46.62, fold endurance increased by 1.78 times (Ma et al, 2021). The dawn et al studied the aged paper by using two nanocelluloses, namely cotton nanocellulose whisker and cotton cellulose nanofibril, and dipped the aged paper in a strengthening solution for 5min, so that the tensile strength is enhanced by about 103% to the maximum, and the folding endurance is improved by about 9.8 times to the maximum (dawn et al, 2017). Bacterial cellulose was pulped by Zhangzhihui from Yunnan university and coated on aged paper at pH 7. The mechanical strength of the repaired paper is improved to a certain extent, the tensile index is improved by 15.8 percent, the tearing index is improved by 12.7 percent, the burst index is improved by 19.8 percent, and the folding index is improved by 91.2 percent (Zhang Shi, 2015). These processes are simple to operate, but none of them deacidify the paper.

In order to simplify the experimental steps and reduce the damage to paper caused by multiple treatments, the research on the deacidification agent and the repairing method which have the multifunctional integration of deacidification, reinforcement, oxidation resistance, antibiosis, water resistance and the like has become the most concerned problem in the ancient book repairing field. Deacidification agents are usually combined with reinforcing agents (Amornkitdamung et al, 2020), or reinforcing agents which are basic in nature (aminosilanes) (Rousset et al, 2004). In the former case, the dispersion of the deacidification agent in the strengthening agent is also an important problem. The Bacterial Cellulose (BC) is a special cellulose material synthesized by microorganisms in vitro, and is a porous reticular nano-scale high molecular polymer. The nanometer network structure of BC can adsorb alkaline nanometer particle stably, and the dispersivity and load stability of nanometer particle can be raised, so that paper can obtain enough alkali storage and long-term alkaline environment. The abundant hydroxyl groups on the surface of the nano-particles can be modified through amination, etherification, silanization and the like, and different groups are grafted, so that the chelating action on the alkaline nano-particles is improved, and the load stability of the alkaline nano-particles is enhanced (Xiaoing et al, 2018; Wu et al, 2019). The multifunctional paper repair liquid using the bacterial cellulose-based alkaline nanoparticles can realize good dispersion of the alkaline nanoparticles and effective enhancement of the paper tension mechanical property. And the alkaline nanoparticles and the bacterial cellulose modified by quaternary ammonium salt and the like can destroy bacterial cell membranes, so that the paper has a certain antibacterial effect (yoget al, 2021). Therefore, the alkaline nano particles neutralize acidic substances in the paper, the BC is adsorbed among paper fibers and on the fiber surface, the binding force among the fibers is enhanced, deacidification, enhancement and antibiosis of aged paper can be realized in one step, and the aged paper can be effectively protected and repaired.

Disclosure of Invention

In order to effectively realize one-step deacidification, reinforcement and antibiosis of aged paper and give proper alkali storage capacity and use durability to the aged paper, the invention aims to provide a preparation method of a multifunctional paper repair liquid containing bacterial cellulose-based alkaline nanoparticles and application of the multifunctional paper repair liquid in aged paper repair. According to the invention, the bacterial cellulose-based material is homogenized under high pressure, proper alkaline nanoparticles are added, and good dispersibility and load stability of the nanoparticles are realized by virtue of the nano-mesh porous structure and the abundant groups on the surface of the bacterial cellulose. The multifunctional paper repairing liquid containing the bacterial cellulose-based alkaline nanoparticles can effectively permeate into the aged paper by combining the porous structure of the aged paper, repair damaged fibers while deacidifying the aged paper, and improve the fiber bonding force, so that the strength of the paper is increased, the stability and durability of the paper in the using process are improved, and the suitable alkaline nanoparticles and the modified bacterial cellulose can effectively resist bacteria. Bacterial cellulose and alkaline nanoparticles are loaded on paper by various methods such as soaking, coating, spraying, atomizing and the like, so that deacidification enhancement and antibacterial treatment on aged paper can be realized in one step, and the paper has important application value in the fields of deacidification, enhancement and antibacterial of aged paper.

The purpose of the invention is realized by the following technical scheme.

A preparation method of a multifunctional paper repair liquid containing bacterial cellulose-based alkaline nanoparticles comprises the following steps:

(1) and (2) disintegrating the bacterial cellulose or modified bacterial cellulose-based material, and carrying out high-pressure homogenization in high-pressure micro-jet nano-dispersion equipment to obtain the bacterial cellulose-based material.

(2) Dispersing the alkaline inorganic nanoparticles in water, ethanol, isopropanol or HMDO solutions with different proportions, uniformly mixing, adding the bacterial cellulose-based material, stirring at room temperature, and performing ultrasonic dispersion treatment to obtain the multifunctional paper repair liquid containing the bacterial cellulose-based alkaline nanoparticles.

(3) Loading the multifunctional paper repair liquid of the bacterial cellulose base alkaline nanoparticles on ancient book paper, and performing deacidification, reinforcement and antibacterial treatment on the ancient book paper.

Further, in the step (1), the bacterial cellulose is directly secreted and synthesized by microorganisms; the modified bacterial cellulose-based material is etherified, aminated, quaternized and silanized modified bacterial cellulose obtained by adopting special bacterial culture solution for culture or modification by chemical reagents.

Further, in the step (1), the culture condition of the microorganism is a static or dynamic fermentation culture condition; the microorganism is one of gluconacetobacter, acetobacter, agrobacterium, pseudomonas, achromobacter, alcaligenes, aerobacter, azotobacter, rhizobium and sarcina.

Further, in the step (1), the special bacteria culture solution comprises a culture solution added with at least one of hydroxylamine hydrochloride, polyacrylamide, polyethyleneimine and ammonia water.

Furthermore, in the step (1), the bacterial cellulose is modified by etherification, namely, the bacterial cellulose is soaked by sodium hydroxide to obtain alkali cellulose, and then the alkali cellulose is subjected to Williamson etherification or Michael addition reaction with an alkyl compound, an alkoxy compound and a vinyl compound, wherein the alkyl compound, the alkoxy compound and the vinyl compound are one of methyl chloride, ethyl chloride, sulfonyl ethane, ethylene oxide and acrylonitrile; the method for aminating and modifying the bacterial cellulose comprises the steps of bonding a nitrogen-containing compound with hydroxyl of the bacterial cellulose, and grafting a nitrogen-containing group, wherein the nitrogen-containing compound is one of hydroxylamine hydrochloride, acrylamide, ethylenediamine, diethylamine, tetraethylenepentamine, dimethylamine and N-methylimidazole; the method for quaternizing the modified bacterial cellulose comprises the steps of swelling the bacterial cellulose by using sodium hydroxide, and then carrying out quaternization reaction on alkyl quaternary ammonium salt or organosilicon quaternary ammonium salt and the bacterial cellulose to connect a quaternary ammonium salt group, wherein the quaternary ammonium salt is one of dodecyl triphenyl ammonium chloride, dimethyl diallyl ammonium chloride, (3-chloro-2-hydroxypropyl) trimethyl ammonium chloride, epoxypropyl trimethyl ammonium chloride and (trimethoxysilylpropyl) octadecyl dimethyl ammonium chloride. The silanization modified bacterial cellulose is prepared by adopting a chemical vapor deposition method or reacting in a water/ethanol/isopropanol system, and introducing silane groups on the surface of the bacterial cellulose through silanization reaction with a silanization reagent, wherein the silanization reagent is one of aminopropyltriethoxysilane, hexadecyltrimethoxysilane, dimethyldichlorosilane, trimethylchlorosilane, diethylaminomethyltriethoxysilane, 3- (2, 3 epoxypropoxy) propylmethyldimethoxysilane and vinyltriethoxysilane. The reactivity and the variety of functional groups on the surface of the bacterial cellulose are improved through modification, more hydrogen bonds and chemical bonds are formed with paper fibers, the fluidity of the bacterial cellulose is improved, the effective permeability of the bacterial cellulose on aged paper and the combination stability of the bacterial cellulose and the paper fibers are realized, and the strength and the use durability of the aged paper fibers are further improved.

Further, in the step (1), the pressure of the high-pressure homogenization is 30-90bar, and the treatment times are 1-10 times. Through high-pressure homogenization, the bacterial cellulose-based material fibers are opened and scattered as much as possible, the dispersibility and the load stability of the bacterial cellulose-based material fibers on alkaline nanoparticles are improved, and the effective deacidification and the proper alkali storage capacity of aged paper are realized.

Further, in the step (2), the basic inorganic nanoparticles MgO, Ca (OH)₂、TiO₂、ZnO，Mg(OH)₂,CaCO₃More than one of (1).

Further, in the step (2), the mass-to-volume ratio of the basic inorganic nanoparticles to water, ethanol, isopropanol or HMDO solution is 1-6g/L, wherein the water accounts for 0-80 wt%, the ethanol accounts for 0-80 wt%, the isopropanol accounts for 0-20 wt%, and the HMDO accounts for 0-80 wt%.

Further, in the step (2), the concentration of the bacterial cellulose-based material is 0.4-1.4 wt%, and the concentration of the alkaline nanoparticles is 0.2-1.0 wt%.

Further, in the step (2), the ultrasonic power of the ultrasonic dispersion treatment is 200-900W, and the time of the ultrasonic dispersion treatment is 20-80 min.

Loading the multifunctional paper repair liquid of the bacterial cellulose base alkaline nanoparticles onto ancient book paper, which comprises the following steps of: after the aged paper is subjected to constant temperature and humidity treatment (the temperature is 23 +/-1 ℃, the humidity is 50 +/-2%, and the treatment time is 24 hours), vacuum drying (the vacuum degree is 0.6bar, the temperature is 35 +/-1 ℃, and the treatment time is 6 hours) treatment is carried out, so that the aged paper after drying treatment is obtained; then treating the paper with the multifunctional paper repair liquid containing the bacterial cellulose-based alkaline nanoparticles, and then placing the paper in a fume hood for air drying treatment to obtain treated aged paper; and (3) naturally drying the treated aged paper, then carrying out constant-temperature and constant-humidity treatment (the temperature is 23 +/-1 ℃, the humidity is 50 +/-2%, and the treatment time is 24h), taking out, and finishing the restoration treatment of the aged paper.

Further, in the step (3), the repairing treatment method of the multifunctional paper repairing solution of bacterial cellulose based alkaline nanoparticles on aged paper is a soaking method, a coating method, a spraying method or an atomizing method. The multifunctional paper repair liquid has the beneficial effects of improving the uniform dispersibility of the multifunctional paper repair liquid containing the bacterial cellulose-based alkaline nanoparticles on aged paper and the binding capacity of the multifunctional paper repair liquid with paper fibers, and improving the mechanical property and the recycling capacity of the multifunctional paper repair liquid.

Further, in the step (3), the method for loading the bacterial cellulose-based basic nanoparticles on the aged paper soaks the aged paper into the repair liquid which is uniformly dispersed.

Further, in the step (3), the bacterial cellulose-based alkaline nanoparticles are loaded on the aged paper by uniformly coating, spin-coating or brush-coating the repair liquid on the aged paper through an automatic coating machine, a coating rod or a coating brush.

Further, in the step (3), the method for loading the bacterial cellulose-based alkaline nanoparticles on the aged paper is a spraying method, namely, the aged paper is placed on a smooth and clean glass plate and is sprayed by using a high-pressure spray can.

Further, in the step (3), the method for loading the bacterial cellulose-based alkaline nanoparticles on the aged paper is to place the aged paper in a closed device, and then introduce the repairing liquid into the closed device after ultrasonic atomization or pressure atomization treatment.

The multifunctional paper repair liquid containing bacterial cellulose base alkaline nanoparticles can perform one-step deacidification, reinforcement and antibiosis on aged paper.

The paper repair liquid consists of 0.4-1.4 wt% of bacterial cellulose or derivatives thereof, 0.2-1.0 wt% of alkaline nanoparticles and 97.6-99.4 wt% of water, ethanol, isopropanol and Hexamethyldisiloxane (HMDO) solvents.

Further, the applications include, but are not limited to, aged paper, silk cultural relics, wood cultural relics, and the like.

Bacterial cellulose and bacterial cellulose derivatives are subjected to disintegration and high-pressure homogenization, and are dispersed into uniform bacterial cellulose-based dispersion liquid; dispersing alkaline inorganic nanoparticles in water, ethanol, isopropanol or HMDO solutions with different proportions, uniformly mixing, adding a bacterial cellulose-based material, performing ultrasonic dispersion treatment to obtain a multifunctional paper repair liquid of the bacterial cellulose-based alkaline nanoparticles, and uniformly loading the multifunctional paper repair liquid on aged paper to realize effective dispersion and acid-base neutralization of the alkaline nanoparticles and effective combination of bacterial cellulose and paper fibers. The paper is soaked in the multifunctional paper repairing liquid containing the bacterial cellulose-based alkaline nanoparticles for 5min, the pH value of the aged paper is increased from 5.12 to 8.55, the alkali reserve is 440mmol/kg, the tear index is increased by 130%, the folding endurance is increased from 12 times to 48 times, the repaired paper has obvious antibacterial effects on escherichia coli and staphylococcus aureus, and the antibacterial zones are 6.78mm and 7.42mm respectively. After 7d of damp heat aging (80 ℃ and 65% RH), the strength of the unrepaired paper is reduced to 50% of the original strength, and the folding times are only 4 times; the strength of the repaired paper is still kept at a high level of 80% of the original strength, the folding times are 38 times, the pH value is 8.15, the alkali storage capacity is 400mmol/kg, and the inhibition zones are 4.42mm and 4.88mm respectively.

Compared with the prior art, the invention has the following advantages:

1. the bacterial cellulose-based material with the nano-network structure is homogenized under high pressure, and is dispersed into stable liquid drops, so that the dispersibility and the load stability of the bacterial cellulose-based material on alkaline nano-particles are improved, and the effective deacidification, reinforcement and antibiosis of aged paper are realized.

2. The method provided by the invention has the advantages that the bacterial cellulose is subjected to activation modification, the reactivity and the types of functional groups on the surface of the bacterial cellulose are increased, the fluidity of the bacterial cellulose is enhanced, the permeability and the combination stability of aged paper fibers are realized, and the effective improvement and the long-term stability of the mechanical properties of the aged paper are realized.

Drawings

FIG. 1 is a flow chart of a preparation method of a multifunctional paper repair liquid containing bacterial cellulose-based alkaline nanoparticles and an application of the multifunctional paper repair liquid in aged paper repair.

Detailed Description

The present invention will be described in further detail below with reference to examples, but the practice of the present invention is not limited thereto.

Example 1

The bacterial cellulose is secreted in vitro by acetobacter gluconicum (gluconacetobacter xylinus). The bacteria culture medium mainly comprises the following components: 50mL of fermented coconut water, 0.1g of ammonium sulfate, 0.1g of magnesium sulfate, 0.1g of potassium dihydrogen phosphate, 3.0g of sucrose and 50mL of distilled water, adjusting the pH value to 4.1 by NaOH, and sterilizing for 5min at 100 ℃. The static fermentation culture method is adopted, the culture medium is placed in a 250mL beaker, and 5% (V/V) of acetobacter gluconicum is inoculated for standing culture for 6 days at the temperature of 30 ℃. The solid content of the obtained bacterial cellulose wet film was 1.5 wt%.

Bacterial Cellulose (BC) wet films were cut into 1cm × 1cm × 0.8mm small pieces, and broken 3 times by a blender in the instant mode. Adding a proper amount of deionized water into the crushed BC, carrying out high-pressure homogenization (for 8 times under the pressure of 60 bar) in high-pressure microfluidization nanometer dispersion equipment, and carrying out low-temperature rotary evaporation to obtain the bacterial cellulose material with the concentration of 0.8 wt%. 0.4g of MgO is dispersed in 100mL of 80 wt% isopropanol solution, and 100g of 0.8 wt% bacterial cellulose material is added to obtain the multifunctional paper repair liquid of bacterial cellulose-based alkaline nanoparticles.

And (3) placing the aged paper on a smooth and clean glass plate, uniformly brushing the bacterial cellulose solution on the surface of the paper by means of surface brushing, repeating for 3-5 times after the paper is slightly dried, and obtaining the reverse side of the paper. And then, naturally airing the treated paper, placing the paper in a constant temperature and humidity chamber with the temperature of 23 ℃ and the RH of 50 percent, and hanging the paper to balance the moisture for 24 hours to obtain the ancient book paper after the bacterial cellulose is repaired.

And (4) detecting the pH value, alkali reserve capacity, whiteness, color difference, tensile strength, tearing strength, bursting strength, folding strength and zero-distance tensile strength of the repaired aged paper. The detection result shows that the surface pH value of the paper repaired by the bacterial cellulose-based alkaline nanoparticles is greatly increased from 4.76 to 8.55, the alkali reserve is 360mmol/kg, and the paper meets the deacidification requirement. The mechanical properties are greatly improved, the tensile index is improved by 60.82%, the tear index is improved by 76.42%, the burst index is improved by 58.44%, the folding index is improved by 180%, and the zero-distance tensile strength is improved by 52.17%. The repaired paper has remarkable bacteriostatic action on escherichia coli and staphylococcus aureus, and the bacteriostatic circles are 3.11mm and 4.26mm respectively. The surface of the treated paper is smooth and tidy, the handwriting is clear, the ink is not obviously affected, the whiteness is slightly increased, the whiteness is improved from 46.43 to 48.88, the generated color difference is invisible to human eyes, and the delta is 0.66.

After 7d of dry heat aging (105 +/-2 ℃), the strength of the unrepaired aged paper is reduced by about 20%, the tensile index is reduced by 16.47%, the tear index is reduced by 14.56%, the burst index is reduced by 20.12%, the folding index is reduced by 30.25%, and the zero-distance tensile strength is reduced by 8.85%. The strength of the repaired paper is still kept at a high level of 93 percent of the original strength, the tensile index is reduced by 7.53 percent, the tear index is reduced by 5.45 percent, the burst index is reduced by 6.74 percent, the folding index is reduced by 12.66 percent, and the zero-distance tensile strength is reduced by 4.37 percent. The pH was 8.15, the alkali storage was still 330mmol/kg, the whiteness was changed from 48.88 to 45.76, the color difference was 0.17, and little change was observed with the naked eye. The unrepaired paper whiteness decreased from 46.43 to 41.22 with a 2.25 color difference, with a slight change visible to the naked eye. In addition, the paper after the 7d aged repair still has the antibacterial effect on escherichia coli and staphylococcus aureus, and the inhibition zones are 2.46mm and 3.57mm respectively.

Example 2

The bacterial cellulose is secreted by acetobacter gluconicum (gluconacetobacter xylinus). The bacteria culture medium mainly comprises the following components: 50mL of fermented coconut water, 0.1g of ammonium sulfate, 0.1g of magnesium sulfate, 0.1g of potassium dihydrogen phosphate, 3.0g of sucrose and 50mL of distilled water, adjusting the pH value to 4.1 by NaOH, and sterilizing for 5min at 100 ℃. The static fermentation culture method is adopted, the culture medium is placed in a 250mL beaker, and 5% (V/V) of acetobacter gluconicum is inoculated for standing culture for 6 days at the temperature of 30 ℃. The solid content of the obtained bacterial cellulose wet film was 1.5 wt%.

30g of Bacterial Cellulose (BC) wet film was cut into small pieces of 1cm × 1cm × 0.8mm, and broken 3 times by a blender in the instant mode. Adding 60g BC into 180mL deionized water, disintegrating, adding 0.42g sodium periodate, shading reaction for 1 day, filtering and washing. Then 150mL of deionized water, 0.44g of sodium cyanoborohydride and 11.2g of polyethyleneimine are added, the pH is adjusted to 5.8-6.0 by 1M hydrochloric acid, the reaction is carried out for 6h at 25 ℃, and the reaction solution is filtered and washed until the supernatant is neutral. Adding a proper amount of BC into 250mL of deionized water, carrying out high-pressure homogenization (homogenizing for 6 times under the pressure of 90 bar) in high-pressure microfluidization nano-dispersion equipment, and carrying out low-temperature rotary evaporation to obtain the bacterial cellulose-based material with the concentration of 1.0 wt%. 0.6g of MgO is dispersed in 50mL of 80 wt% ethanol solution, and 50g of 1.0 wt% bacterial cellulose material is added to obtain the multifunctional paper repair liquid containing bacterial cellulose-based alkaline nanoparticles.

And (3) soaking the pretreated aged paper into the uniformly dispersed paper repairing liquid for 5min, naturally drying, and vacuum-drying at 35 ℃ for 6 h. And then placing the paper in a constant temperature and humidity chamber with the temperature of 23 ℃ and the RH of 50 percent to be hung, and balancing the moisture for 24 hours to obtain the aged paper after the bacterial cellulose base alkaline nano particles are repaired.

And (4) detecting the pH value, alkali reserve capacity, whiteness, color difference, tensile strength, tearing strength, bursting strength, folding strength and zero-distance tensile strength of the repaired aged paper. The detection result shows that the surface pH value of the paper repaired by the bacterial cellulose-based alkaline nanoparticles is greatly increased from 4.88 to 8.73, the alkali reserve is 400mmol/kg, and the paper meets the deacidification requirement. The mechanical properties are greatly improved, the tensile index is improved by 73.52 percent, the tear index is improved by 88.75 percent, the burst index is improved by 62.17 percent, the folding index is improved by 238 percent, and the zero-distance tensile strength is improved by 59.14 percent. The repaired paper has remarkable bacteriostatic action on escherichia coli and staphylococcus aureus, and the bacteriostatic circles are 3.86mm and 5.11mm respectively. The surface of the treated paper is smooth and tidy, the handwriting is clear, the ink is not obviously affected, the whiteness is slightly increased, the whiteness is improved from 47.52 to 49.25, the generated color difference is invisible to human eyes, and the delta is 1.26.

After 15 days of damp heat aging (80 ℃ and 65% RH), the unrepaired aged paper strength is reduced by about 40%, the tensile index is reduced by 44.13%, the tear index is reduced by 34.17%, the burst index is reduced by 37.52%, the folding index is reduced by 50.53%, and the zero-distance tensile strength is reduced by 18.14%. The strength of the repaired paper is still kept at a high level of 80 percent of the original strength, the tensile index is reduced by 21.92 percent, the tear index is reduced by 18.77 percent, the burst index is reduced by 20.43 percent, the folding index is reduced by 27.51 percent, and the zero-distance tensile strength is reduced by 10.25 percent. The pH was 8.11, the alkali reserve was still 340mmol/kg, the whiteness was changed from 49.25 to 43.61, the color difference was 1.67, and a slight change was visible to the naked eye. While the unrepaired paper whiteness was reduced from 47.52 to 38.73 with a color difference of 4.52 and a noticeable change to the naked eye. In addition, the paper after the 15d aged repair still has the antibacterial effect on escherichia coli and staphylococcus aureus, and the antibacterial zones are 1.97mm and 2.55mm respectively.

Example 3

The bacterial cellulose is secreted by acetobacter gluconicum (gluconacetobacter xylinus). The bacteria culture medium mainly comprises the following components: 50mL of fermented coconut water, 0.1g of ammonium sulfate, 0.1g of magnesium sulfate, 0.1g of monopotassium phosphate, 3.0g of cane sugar, 50mL of distilled water and 5mL of acrylamide, adjusting the pH value to 4.1 by NaOH, and sterilizing for 5min at 100 ℃. The static fermentation culture method is adopted, the culture medium is placed in a 250mL beaker, and 5% (V/V) of acetobacter gluconicum is inoculated for standing culture for 6 days at the temperature of 30 ℃. The wet film solid content of the obtained acrylamide-modified bacterial cellulose was 1.8 wt%.

Acrylamide modified Bacterial Cellulose (BC) wet film was cut into small pieces of 1cm × 1cm × 0.8mm, and broken 3 times by a blender in the instant mode. Adding a proper amount of acrylamide modified BC into 250mL of deionized water, carrying out high-pressure homogenization (homogenizing for 10 times under the pressure of 30 bar) in high-pressure microfluidization nanometer dispersion equipment, and carrying out low-temperature rotary evaporation to obtain the bacterial cellulose-based material with the concentration of 1.2 wt%. 0.6g of ZnO is dispersed in 50mL of 80 wt% HMDO solution, and 50g of 1.2 wt% bacterial cellulose material is added to obtain the multifunctional paper repair liquid containing bacterial cellulose base alkaline nanoparticles.

And clamping the aged paper on an automatic coating machine, and coating the multifunctional paper repairing liquid containing the bacterial cellulose base alkaline nanoparticles on the paper by adopting the automatic coating machine. Repeating for 2-3 times after drying, and repeating for 2-3 times on the reverse side. Naturally airing the paper, placing the paper in a constant temperature and humidity chamber with the temperature of 23 ℃ and the RH of 50 percent, and suspending the paper to balance the moisture for 24 hours to obtain the aged paper repaired by the bacterial cellulose based alkaline nano particles.

And (4) detecting the pH value, alkali reserve capacity, whiteness, color difference, tensile strength, tearing strength, bursting strength, folding strength and zero-distance tensile strength of the repaired aged paper. The detection result shows that the surface pH value of the paper repaired by the bacterial cellulose-based alkaline nanoparticles is greatly increased from 4.42 to 8.53, and the alkali reserve is 380mmol/kg, so that the deacidification requirement is met. The mechanical properties are greatly improved, the tensile index is improved by 48.77 percent, the tear index is improved by 51.42 percent, the burst index is improved by 44.56 percent, the folding index is improved by 120 percent, and the zero-distance tensile strength is improved by 37.53 percent. The repaired paper has obvious bacteriostatic action on escherichia coli and staphylococcus aureus, and the bacteriostatic zones are 5.56mm and 5.88mm respectively. The surface of the treated paper is smooth and tidy, the handwriting is clear, the ink is not obviously affected, the whiteness is slightly increased, the whiteness is improved from 46.34 to 47.72, the generated color difference is invisible to human eyes, and the delta is 1.31.

After 3d of dry heat aging (105 +/-2 ℃), the strength of the unrepaired aged paper is reduced by about 10%, the tensile index is reduced by 11.34%, the tear index is reduced by 10.52%, the burst index is reduced by 9.77%, the folding index is reduced by 16.45%, and the zero-distance tensile strength is reduced by 3.35%. The strength and whiteness of the repaired paper are almost unchanged, the pH value is 8.48, and the alkali reserve is still 370 mmol/kg. The unrepaired paper whiteness dropped from 46.34 to 44.15 with a 1.22 color difference, with a slight change to the naked eye. In addition, the aged 3d repaired paper still has obvious bacteriostatic action on escherichia coli and staphylococcus aureus, and the bacteriostatic rings are 5.38mm and 5.52mm respectively.

Example 4

The bacterial cellulose is secreted by acetobacter gluconicum (gluconacetobacter xylinus). The bacteria culture medium mainly comprises the following components: 50mL of fermented coconut water, 0.1g of ammonium sulfate, 0.1g of magnesium sulfate, 0.1g of monopotassium phosphate, 3.0g of cane sugar and 50mL of distilled water, and sterilizing for 5min at 100 ℃. The static fermentation culture method is adopted, the culture medium is placed in a 250mL beaker, and 5% (V/V) of acetobacter gluconicum is inoculated for standing culture for 6 days at the temperature of 30 ℃. The solid content of the obtained bacterial cellulose wet film was 1.5 wt%.

30g of BC wet film was cut into small pieces of 1cm X0.8 mm, and broken by a blender in an instant modeCrushing for 3 times, filtering and washing. Adding the mixture into 5% sodium hydroxide mixed solution, reacting for 30min at 30 ℃, washing, filtering, adding (3-chloro-2-hydroxypropyl) trimethyl ammonium chloride to enable the molar ratio of the trimethyl ammonium chloride to the anhydrous glucose units in BC to be 2:1, reacting for 6h at 40 ℃, and washing with deionized water to be neutral. Homogenizing at high pressure (30bar for 10 times) in high pressure microfluidization nanometer dispersing equipment, and performing rotary evaporation at low temperature to obtain bacterial cellulose-based material with concentration of 0.6 wt%. 1.0g of CaCO₃Dispersing in 100mL of deionized water, and adding 100g of 0.6 wt% of bacterial cellulose material to obtain the multifunctional paper repair liquid containing the bacterial cellulose-based alkaline nanoparticles.

The aged paper is suspended in a volume of about 6dm³In the cuboid closed deacidification equipment, the multifunctional paper repair liquid of the bacterial cellulose base alkaline nanoparticles is atomized by ultrasonic atomization equipment with the power of 55W, and the multifunctional paper repair liquid is introduced into the equipment to treat paper for 60 min. And then, naturally airing the treated paper, placing the paper in a constant temperature and humidity chamber with the temperature of 23 ℃ and the RH of 50 percent, and suspending the paper to balance moisture for 24 hours to obtain the aged paper repaired by the bacterial cellulose base alkaline nano particles.

And (4) detecting the pH value, alkali reserve capacity, whiteness, color difference, tensile strength, tearing strength, bursting strength, folding strength and zero-distance tensile strength of the repaired aged paper. The detection result shows that the surface pH value of the paper repaired by the bacterial cellulose-based alkaline nanoparticles is greatly increased from 5.46 to 8.18, the alkali reserve is 360mmol/kg, and the paper meets the deacidification requirement. The mechanical properties are greatly improved, the tensile index is improved by 45.52 percent, the tear index is improved by 48.86 percent, the burst index is improved by 41.55 percent, the folding index is improved by 88.64 percent, and the zero-distance tensile strength is improved by 30.12 percent. The repaired paper has remarkable bacteriostatic action on escherichia coli and staphylococcus aureus, and the bacteriostatic circles are 7.73mm and 8.29mm respectively. The surface of the treated paper is smooth and tidy, the handwriting is clear, the ink is not obviously affected, the whiteness is slightly increased, the whiteness is improved from 48.16 to 49.65, the generated color difference is invisible to human eyes, and the delta is 0.76.

After 30d of dry heat aging (105 +/-2 ℃), the strength of the unrepaired aged paper is reduced by 50-60%, the tensile index is reduced by 52.67%, the tear index is reduced by 48.73%, the burst index is reduced by 50.52%, the folding index is reduced by 90.16%, and the zero-distance tensile strength is reduced by 38.47%. The repaired paper has higher strength, the tensile index of the repaired paper is reduced by 30.12 percent, the tearing index is reduced by 30.62 percent, the bursting index is reduced by 36.37 percent, the folding index is reduced by 67.22 percent, and the zero-distance tensile strength is reduced by 19.68 percent. The pH was 7.35, the alkali reserve was still 240mmol/kg, the whiteness was changed from 49.65 to 40.12, the color difference was 4.10, and some change was visible to the naked eye. The brightness of the unrepaired paper is reduced from 48.19 to 33.65, the color difference is 8.77, and obvious change can be seen by naked eyes. In addition, the paper after 30d of aging repair still has the antibacterial effect on escherichia coli and staphylococcus aureus, and the inhibition zones are 2.17mm and 2.33mm respectively.

Example 5

The bacterial cellulose is secreted by acetobacter gluconicum (gluconacetobacter xylinus). The bacteria culture medium mainly comprises the following components: 50mL of fermented coconut water, 0.1g of ammonium sulfate, 0.1g of magnesium sulfate, 0.1g of monopotassium phosphate, 3.0g of cane sugar and 50mL of distilled water, and sterilizing for 5min at 100 ℃. The static fermentation culture method is adopted, the culture medium is placed in a 250mL beaker, and 5% (V/V) of acetobacter gluconicum is inoculated for standing culture for 6 days at the temperature of 30 ℃. The solid content of the obtained bacterial cellulose wet film was 1.5 wt%.

The wet BC membranes were cut into small pieces of 1cm by 0.8mm, broken 3 times in the instant mode by a blender, filtered and washed. 40ml of 80% ethanol solution is put into a three-neck flask, 1.6ml of Aminopropyltriethoxysilane (APS) is slowly dropped, and stirring is carried out for 30min, so that the APS is fully hydrolyzed. 22.22g of BC was added, reacted at 60 ℃ for 1 hour, washed by centrifugation, and filtered to obtain APS-BC. Homogenizing at high pressure (60bar for 10 times) in high pressure microfluidization nanometer dispersing equipment, and performing rotary evaporation at low temperature to obtain bacterial cellulose-based material with concentration of 0.4 wt%. 0.4g of TiO₂Dispersing in 100mL of 20 wt% ethanol solution, and adding 100g of 0.4 wt% bacterial cellulose material to obtain the multifunctional paper repairing liquid containing bacterial cellulose-based alkaline nanoparticles.

And clamping the aged paper on an automatic coating machine, and coating the multifunctional paper repairing liquid containing the bacterial cellulose base alkaline nanoparticles on the paper by adopting the automatic coating machine. Repeating for 2-3 times after drying, and repeating for 2-3 times on the reverse side. Naturally airing the paper, placing the paper in a constant temperature and humidity chamber with the temperature of 23 ℃ and the RH of 50 percent, and suspending the paper to balance the moisture for 24 hours to obtain the aged paper repaired by the bacterial cellulose based alkaline nano particles.

And (4) detecting the pH value, alkali reserve capacity, whiteness, color difference, tensile strength, tearing strength, bursting strength, folding strength and zero-distance tensile strength of the repaired aged paper. The detection result shows that the surface pH value of the paper repaired by the bacterial cellulose-based alkaline nanoparticles is greatly increased from 6.12 to 8.33, the alkali reserve is 310mmol/kg, and the paper meets the deacidification requirement. The mechanical properties are greatly improved, the tensile index is improved by 31.44 percent, the tear index is improved by 38.52 percent, the burst index is improved by 38.16 percent, the folding index is improved by 50.74 percent, and the zero-distance tensile strength is improved by 14.76 percent. The repaired paper has obvious bacteriostatic action on escherichia coli and staphylococcus aureus, and the bacteriostatic zones are 5.13mm and 5.66mm respectively. The surface of the treated paper is smooth and tidy, the handwriting is clear, the ink is not obviously affected, the whiteness is slightly increased, the whiteness is improved from 49.23 to 50.18, the generated color difference is invisible to human eyes, and the delta is 0.24.

After 3d of dry heat aging (105 +/-2 ℃), the strength of the unrepaired aged paper is reduced by about 15%, the tensile index is reduced by 16.33%, the tear index is reduced by 15.84%, the burst index is reduced by 14.62%, the folding index is reduced by 28.17%, and the zero-distance tensile strength is reduced by 3.56%. The strength and whiteness of the repaired paper are almost unchanged, the pH value is 8.15, and the alkali reserve is 300 mmol/kg. The brightness of the unrepaired paper changed from 49.65 to 47.52 with a 1.18 color difference, with a slight change to the naked eye. In addition, the repaired paper aged for 3d still has antibacterial effect on escherichia coli and staphylococcus aureus, and the antibacterial zones are 4.73mm and 5.12mm respectively.

Example 6

The bacterial cellulose is secreted by acetobacter gluconicum (gluconacetobacter xylinus). The bacteria culture medium mainly comprises the following components: 50mL of fermented coconut water, 0.1g of ammonium sulfate, 0.1g of magnesium sulfate, 0.1g of monopotassium phosphate, 3.0g of cane sugar and 50mL of distilled water, and sterilizing for 5min at 100 ℃. The static fermentation culture method is adopted, the culture medium is placed in a 250mL beaker, and 5% (V/V) of acetobacter gluconicum is inoculated for standing culture for 6 days at the temperature of 30 ℃. The solid content of the obtained bacterial cellulose wet film was 1.5 wt%.

The wet BC membranes were cut into small pieces of 1cm by 0.8mm, broken 3 times in the instant mode by a blender, filtered and washed. Placing the BC into a conical flask, adding 180mL of deionized water and 0.42g of sodium periodate, magnetically stirring at room temperature and 350rpm for light-shielding reaction for 48 hours, and performing suction filtration and washing by using the deionized water until the reaction is neutral to obtain the dialdehyde BC. 160mL of deionized water, 0.44g of sodium cyanoborohydride, and 11.2g of polyethyleneimine are added to bisaldehyde BC, the pH is adjusted to 5.8-6.0 with 1M hydrochloric acid, and the reaction is continued at 25 ℃ for 6 hours at the reaction temperature. After the reaction is finished, deionized water is used for suction filtration and washing until the supernatant is neutral, and the obtained solid is the polyethyleneimine BC (PEI-BC). Homogenizing under high pressure in high pressure micro-jet nanometer dispersing equipment (homogenizing for 8 times under 60bar pressure), and performing rotary evaporation at low temperature to obtain bacterial cellulose base material with concentration of 0.8 wt%. 0.6g of Ca (OH)₂Dispersing in 100mL of 40 wt% ethanol solution, and adding 100g of 0.8 wt% bacterial cellulose material to obtain the multifunctional paper repairing liquid containing bacterial cellulose-based alkaline nanoparticles.

And clamping the aged paper on an automatic coating machine, and coating the multifunctional paper repairing liquid containing the bacterial cellulose base alkaline nanoparticles on the paper by adopting the automatic coating machine. Repeating for 2-3 times after drying, and repeating for 2-3 times on the reverse side. Naturally airing the paper, placing the paper in a constant temperature and humidity chamber with the temperature of 23 ℃ and the RH of 50 percent, and suspending the paper to balance the moisture for 24 hours to obtain the aged paper repaired by the bacterial cellulose based alkaline nano particles.

And (4) detecting the pH value, alkali reserve capacity, whiteness, color difference, tensile strength, tearing strength, bursting strength, folding strength and zero-distance tensile strength of the repaired aged paper. The detection result shows that the surface pH value of the paper repaired by the bacterial cellulose-based alkaline nanoparticles is greatly increased from 5.88 to 8.24, the alkali reserve is 300mmol/kg, and the paper meets the deacidification requirement. The mechanical properties are greatly improved, the tensile index is improved by 41.36 percent, the tear index is improved by 48.64 percent, the burst index is improved by 43.57 percent, the folding index is improved by 56.83 percent, and the zero-distance tensile strength is improved by 31.14 percent. The repaired paper has obvious bacteriostatic action on escherichia coli and staphylococcus aureus, and the bacteriostatic zones are 5.47mm and 5.81mm respectively. The surface of the treated paper is smooth and tidy, the handwriting is clear, the ink is not obviously affected, the whiteness is slightly increased, the whiteness is improved from 48.77 to 50.03, the generated color difference is invisible to human eyes, and the delta is 0.19.

After 7 days of damp heat aging (80 ℃ and 65% RH), the unrepaired aged paper strength is reduced by about 40%, the tensile index is reduced by 44.15%, the tear index is reduced by 42.63%, the burst index is reduced by 40.44%, the folding index is reduced by 50.82%, and the zero-distance tensile strength is reduced by 30.73%. The strength of the repaired paper is still kept at a high level of 75 percent of the original strength, the tensile index is reduced by 22.67 percent, the tear index is reduced by 23.15 percent, the burst index is reduced by 26.54 percent, the folding index is reduced by 28.44 percent, and the zero-distance tensile strength is reduced by 14.57 percent. The pH was 7.95, the alkali reserve was still 270mmol/kg, the whiteness was changed from 50.03 to 48.57, the color difference was 1.83, and a slight change was visible to the naked eye. The brightness of the unrepaired paper is reduced from 48.77 to 43.21, the color difference is 2.68, and obvious change can be seen by naked eyes. In addition, the paper after 7d of aging repair still has the antibacterial effect on escherichia coli and staphylococcus aureus, and the inhibition zones are 4.36mm and 4.55mm respectively.

The preparation method of the multifunctional paper repair liquid containing bacterial cellulose-based alkaline nanoparticles and the application flow chart of the multifunctional paper repair liquid in aged paper repair are shown in figure 1.

The foregoing lists merely illustrate specific embodiments of the invention. The present invention is not limited to the above embodiments, and many variations are possible. All modifications which can be derived or suggested by a person skilled in the art from the disclosure of the present invention are to be considered within the scope of the invention.