CN117107548B - Preparation method and application of composite deacidification material with high alkali reserve and hydrophobicity after deacidification treatment of paper - Google Patents

Abstract

The invention discloses a preparation method and application of a composite deacidification material with high alkali reserves and hydrophobicity after deacidification treatment of paper, and belongs to the technical field of deacidification treatment of precious paper cultural relics and the like. The composite deacidification material is prepared from nano alkaline compound magnesium hydroxide Mg (OH) ₂ Or calcium hydroxide Ca (OH) ₂ The surface coating fluoroalkyl methacrylate polymer (PPFOEMA). The PPFOEMA polymer is coated to enable the composite deacidification material to be suspended and dispersed in fluorocarbon medium in high stability for high-efficiency deacidification treatment of paper; the composite deacidification material is easy to uniformly infiltrate into the fiber gaps of the paper, and the PPFOEMA polymer coated on the surfaces of the nano particles can delay the release of alkaline compounds, so that the deacidified paper is still slightly alkaline under the condition of high alkali reserves, has excellent hydrophobicity and certain reinforcement effect, and is convenient for long-term storage.

Description

A composite deacidification material that has high alkali storage and hydrophobicity after deacidification of paper Material preparation methods and applications

Technical field

The invention relates to a method and application of a composite deacidification material that enables paper to have high alkali reserves and hydrophobicity after deacidification treatment. The composite deacidification material is used in the deacidification treatment of precious paper cultural relics, archives, books, etc. .

Background technique

Paper is the most common base material for recording information. It bears the important task of inheriting human civilization and development, and is an indispensable and important part of the development of human history. However, hundreds of millions of paper materials around the world are currently undergoing severe aging and degradation (Trends in Microbiology, 2010, 18:538-542). The main reason is the acidic substances present in paper. Acidic substances in paper generally come from acidic sizing agents in the papermaking process, acidic gases such as sulfur oxides and nitrogen oxides in the storage environment, and organic acids produced by bacterial metabolism. These acidic substances will accelerate the hydrolysis of paper cellulose, leading to The polymerization degree of cellulose decreases, and the paper turns yellow and brittle, seriously endangering the life of paper cultural relics. Therefore, it is urgent to deacidify and strengthen fragile paper documents.

The paper deacidification process is divided into aqueous phase deacidification, organic phase deacidification and gas phase deacidification according to the medium in which the alkaline deacidification material is located. Among them, the aqueous phase deacidification process has been applied on a large scale because of its advantages of safety, efficiency, and easy operation, such as the German Vienna method (Journal of Colloid and Interface Science, 2022, 607:992-1004) and the Austrian Vienna method ( Chimia International Journal for Chemistry,2001,55:981-989) etc. However, the paper after aqueous phase deacidification will wrinkle; and the organic media such as methanol and isopropyl alcohol used in organic phase deacidification are not only flammable and explosive, but also unfriendly to the human body and the environment. In order to overcome the above shortcomings, the use of inert organic media to suspend and disperse alkaline deacidification materials has gradually become the mainstream process for large-scale paper deacidification in recent years. The most representative one is the Bookkeeper method using perfluoroheptane medium (Microporous and Mesoporous Materials, 2020, 293:109786). Perfluoroheptane and other perfluorinated alkanes have the advantages of being non-flammable, non-explosive, good chemical stability, easy to volatilize without residue, and good permeability (Journal of Photochemistry and Photobiology A: Chemistry, 2010, 214:86-91). However, perfluoroalkane media have low surface tension, are hydrophobic and oleophobic, making it difficult for alkaline deacidification materials to be uniformly and stably suspended and dispersed in it (CN20161025757.2), which will cause uneven deacidification of paper and There are a series of problems such as poor effect and low utilization rate of deacidification materials. Our previously disclosed invention has better solved the problem of highly stable suspension and dispersion of alkaline deacidification materials in fluorocarbon media (CN114753186A, a paper deacidification composite material with high stability suspension and dispersion in fluorocarbon media and its preparation method and Application; CN108589411A, an attapulgite composite material and its application).

Existing paper deacidification technologies are developed based on the acid-alkali neutralization principle, that is, alkaline substances are used to neutralize acidic substances in paper to inhibit acid-catalyzed hydrolysis of paper cellulose, thereby extending its life. As we all know, if paper after deacidification treatment does not return to acid for a long time, it must store a certain amount of alkaline substances. The definition and quantitative determination method of alkali reserves can be based on the national standard GB/T 24998-2010 method. This part of the stored alkaline substances is used to neutralize the acidic substances produced due to natural aging of the paper during subsequent storage after deacidification, which can reduce the aging speed of the paper and extend the storage life of the paper. However, the excessively high alkali reserve of paper after deacidification treatment will often cause the paper to have an excessively high pH value, and an excessively high pH value will also adversely affect the life of the paper (Carbohydrate Polymers, 2019, 209:250-257 ). Therefore, how to make the deacidified paper have a high alkali reserve and a suitable pH value, that is, how to make the alkaline substances stored in the paper have a certain degree of sustained release, is an important issue we need to solve.

Cellulose, the main component of paper, is a natural hygroscopic material and is generally hydrophilic. At the same time, the three-dimensional network-like rich microporous structure formed by cross-linking between cellulose has capillary cohesion, thus showing strong water absorption. properties and wettability. Not only does the strength of paper after absorbing water drop significantly, it is also more likely to combine with acidic substances in the air, thereby accelerating the aging of the paper. In contrast, hydrophobic paper does not absorb water easily and has good self-cleaning and anti-corrosion properties. In particular, hydrophobic paper can also effectively prevent papers from adhering to each other during batch deacidification (International Journal of Biological Macromolecules, 2022, 207: 232-241; Cellulose, 2022, 29: 8863-8877), thus having It is conducive to large-scale and effective deacidification treatment of paper. Therefore, how to make the deacidified paper have a certain degree of hydrophobicity is another important issue we need to solve.

Contents of the invention

The object of the present invention is not only to provide a method for preparing a composite deacidification material that is highly stable suspended and dispersed in a fluorocarbon medium, but also to provide a composite deacidification material that has the characteristics of high alkali storage and hydrophobicity after deacidification treatment. Preparation methods of acid materials to further innovatively develop existing technologies. The technical solution proposed by the present invention is to pre-adsorb the fluoroalkyl methacrylate (PFOEMA) monomer capable of polymerization on the inorganic nano-alkaline deacidification material, and then polymerize it in situ to form a composite deacidification material. The paper deacidified by the composite deacidification material is still weakly alkaline under high alkali reserves and has a certain degree of hydrophobicity. The composite deacidification material is a "core-shell" with the alkaline compound magnesium hydroxide Mg(OH) ₂ or calcium hydroxide Ca(OH) ₂ as the core and fluoroalkyl methacrylate polymer (PPFOEMA) as the shell. "Structure, not only has highly stable suspension and dispersion in fluorocarbon media, but also the composite material can easily penetrate into the gaps of paper fibers evenly. The PPFOEMA polymer shell coated on the surface of the alkaline compound Mg(OH) or Ca(OH) ₂ nanoparticles can delay the release of alkaline substances in the core. The paper after deacidification of the composite material has a high alkali reserve. It is still weakly alkaline; and the PPFOEMA polymer present on the surface of the composite deacidification material that penetrates into the paper fiber gaps has a certain degree of hydrophobicity; furthermore, the composite deacidification material that penetrates into the paper fiber gaps can also improve the mechanical properties of the paper. strength. Another object of the present invention is to provide the application of the composite deacidification material prepared by the above method in paper deacidification.

In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

A method for preparing a composite deacidification material that enables paper to have high alkali storage and hydrophobicity after deacidification treatment. The steps are as follows:

1) Add hydrazine hydrate (N ₂ H ₄ ·H ₂ O) aqueous solution to sodium hydroxide (NaOH) aqueous solution to obtain a precipitant solution;

2) Prepare an ethanol (CH ₃ CH ₂ OH) solution containing calcium ions (Ca ²⁺ ) or magnesium ions (Mg ²⁺ ) and fluoroalkyl methacrylate;

3) Mix and stir the solutions of steps 1) and 2), and place them in a reaction kettle for temperature-controlled reaction;

4) The reacted mixture is centrifuged, washed, and dried to obtain a solid composite deacidification material.

According to the preparation method of a composite deacidification material that makes paper have high alkali reserve and hydrophobicity after deacidification treatment, the alkaline compound in the solid composite deacidification material is any one of magnesium hydroxide and calcium hydroxide.

According to the method for preparing a composite deacidification material with high alkali reserve and hydrophobicity after deacidification treatment of paper, the mass fraction of the alkaline compound in the solid composite deacidification material is 50 to 95%.

According to the preparation method of the composite deacidification material that makes paper have high alkali reserve and hydrophobicity after deacidification treatment, the temperature of the temperature-controlled reaction in the reactor is 150°C, and the reaction time is 12 hours.

The composite deacidification material obtained by the method enables the paper to have high alkali reserve and hydrophobicity after deacidification treatment.

The composite deacidification material with high alkali reserve and hydrophobicity after deacidification treatment of paper is used for deacidification of paper.

In the described application, the composite deacidification material is first dispersed in a fluorocarbon medium, subjected to ultrasonic treatment, and then used for paper deacidification.

The fluorocarbon medium is perfluorooctane, perfluoroheptane, perfluorononane, perfluorobutyltetrahydrofuran, perfluorocyclic ether, perfluorocyclohexane, perfluoromethylcyclohexane, and perfluorotoluene , one or more of perfluoro-2,7-dimethyloctane.

The specific steps for the described application are:

(1) Disperse the composite deacidification material in the fluorocarbon medium, and conduct ultrasonic treatment for 30 minutes to form a suspension. The concentration of the composite deacidification material is 3.0 to 10.0g/L;

(2) Soak the paper to be deacidified in the suspension obtained in step (1) for 30 minutes, and then dry it at room temperature to complete the paper deacidification treatment.

The chemical formulas of the fluoroalkyl methacrylate (PFOEMA) are as follows (1) and (2):

In (1): the value of n is 4 to 11; in (2): the value of n is 0 to 3, and the value of x is 0 to 2.

Further, the fluoroalkyl methacrylate is 2-(perfluorooctyl)ethyl methacrylate, which has the structure shown in (3);

The paper provided by the invention is a composite deacidification material with high alkali reserve and hydrophobicity after deacidification treatment. The precipitant sodium hydroxide and hydrazine hydrate aqueous solution are used to precipitate calcium ions (Ca ²⁺ ) or magnesium ions (Mg ²⁺ ), first generate the basic compound Ca(OH) ₂ or Mg(OH) ₂ , then pre-adsorb the fluoroalkyl methacrylate (PFOEMA) monomer, and then undergo in-situ polymerization to generate fluoroalkyl methyl Prepared from acrylate (PPFOEMA) polymer. Experimental results show that the composite deacidification material is a "core-shell" structure Ca(OH) ₂ @PPFOEMA or Mg with alkaline compound Ca(OH ₎ 2 or Mg(OH) ₂ nanoparticles as the core and PPFOEMA polymer as the shell. (OH) ₂ @PPFOEMA (see Figure 1 and Figure 2) not only shows highly stable suspension and dispersion in fluorocarbon media (see Figure 3), but also the composite deacidification material is easy to dissolve during the deacidification process. Evenly penetrate into the paper fiber gaps (see attached picture 4). As shown in Table 1, the deacidified paper has a high alkali reserve of 466.29mmol/kg, and the PPFOEMA polymer shell coated on the surface of the alkaline compound Mg(OH) ₂ or Ca(OH) ₂ nanoparticles can delay The release of alkaline substances in the core makes the deacidified paper still weakly alkaline (pH value between 7 and 8) with high alkali reserves; and, the composite deacidification that penetrates into the gaps in the paper fibers The hydrophobicity of the PPFOEMA polymer on the surface of the material makes the paper after deacidification treatment have a certain degree of hydrophobicity. The stable contact angle with water increases significantly from 25° before deacidification treatment to 130° after deacidification treatment. °; In particular, the composite deacidification material that penetrates into the gaps between paper fibers can also improve the mechanical strength of the paper.

Compared with the existing technology, the beneficial effects of the present invention are:

1) The fluoroalkyl methacrylate polymer (PPFOEMA) coated on the surface of the composite deacidification material enables it to be suspended and dispersed in a fluorocarbon medium with high stability, and the composite material can easily penetrate into the gaps of paper fibers evenly, and The PPFOEMA polymer shell coated on the surface of the alkaline compound Mg(OH) ₂ or Ca(OH) ₂ nanoparticles can delay the release of alkaline substances in the core. The paper after deacidification of the composite material has high alkali reserves. It is still weakly alkaline even under deacidification conditions; the present invention not only solves the problem of poor suspension and dispersion stability of deacidification materials in fluorocarbon media, but also solves the problem of low alkali reserves and easy to use of existing deacidification materials in paper after deacidification treatment. Problems such as acid return or high alkali storage but the pH of the paper surface is too high;

2) The PPFOEMA polymer coated on the surface of the composite deacidification material prepared by the present invention is hydrophobic. During the deacidification process, the composite deacidification material evenly penetrates into the gaps in the paper fibers so that the surface of the paper also exhibits strong hydrophobicity, which is beneficial to the paper. preservation;

3) The present invention adopts the in-situ polymerization reaction method to prepare the nano-alkaline Ca(OH) ₂ or Mg(OH) ₂ composite material surface-coated with PPFOEMA polymer. The method is simple, the steps are simple, and the synthesis efficiency is high. The prepared composite The deacidification material is used for paper deacidification treatment and has the characteristics of good paper deacidification effect, high alkali reserve, moderate surface pH, good hydrophobicity and significant reinforcement effect.

Description of drawings

Figure 1 is a scanning electron microscope (SEM) image of the Mg(OH) ₂ @PPFOEMA sample of Example 2, where PPFOEMA is a 2-(perfluorooctyl)ethyl methacrylate polymer;

Figure 2 shows the infrared spectra of Mg(OH) ₂ (a), Mg(OH) ₂ @PPFOEMA (b) prepared in Example 2 and PFOEMA monomer (c), where PFOEMA is 2-(perfluorooctyl) Ethyl methacrylate;

Figure 3 is an optical photograph of the suspension of the composite deacidification material Mg(OH) ₂ @PPFOEMA prepared in Example 2 (Fig. 3A) and the optical photograph of the suspension of Mg(OH) ₂ in Comparative Example 1 (Fig. 3B);

Figure 4 is a SEM image of the paper before deacidification (Figure 4A) and after deacidification treatment of the composite deacidification material Mg(OH) ₂ @PPFOEMA prepared in Example 18 (Figure 4B);

Figure 5 shows (a) before paper deacidification, (b) after deacidification of the composite deacidification material Mg(OH) ₂ @PPFOEMA prepared in Example 18, and (c) after aging treatment and water stability. Contact angle.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described below in conjunction with specific embodiments. Unless otherwise specified in the following examples, the technical means used are conventional means well known to those skilled in the art.

Example 1

Dissolve 0.429g magnesium acetate tetrahydrate in 20mL absolute ethanol under the action of ultrasonic waves (power 70w, frequency 40Khz), and add 0.1g 2-(perfluorooctyl)ethyl methacrylate (PFOEMA) monomer, Stir at room temperature and set aside; dissolve 0.16g sodium hydroxide in 20mL aqueous solution, and add 4mL of hydrazine hydrate with a mass fraction of 80% to prepare a precipitate; slowly drop the precipitate into the above standby solution and stir at room temperature 30min, then move the mixed solution into a 100mL reactor lined with polytetrafluoroethylene and react at 150°C for 12h. After cooling to room temperature, centrifuge and wash to remove impurities to obtain the composite deacidification material Mg(OH ) ₂ @PPFOEMA, the mass fraction of magnesium hydroxide in the solid composite deacidification material is 90 to 95%.

Example 2

Dissolve 0.429g magnesium acetate tetrahydrate in 20mL absolute ethanol under the action of ultrasonic waves (power 70w, frequency 40Khz), and add 0.2g 2-(perfluorooctyl)ethyl methacrylate (PFOEMA) monomer, Stir at room temperature and set aside; dissolve 0.16g sodium hydroxide in 20mL aqueous solution, and add 4mL of hydrazine hydrate with a mass fraction of 80% to prepare a precipitate; slowly drop the precipitate into the above standby solution and stir at room temperature 30min, then move the mixed solution into a 100mL reactor lined with polytetrafluoroethylene and react at 150°C for 12h. After cooling to room temperature, centrifuge and wash to remove impurities to obtain the composite deacidification material Mg(OH ) ₂ @PPFOEMA, the mass fraction of magnesium hydroxide in the solid composite deacidification material is 80 to 85%.

Example 3

Dissolve 0.429g magnesium acetate tetrahydrate in 20mL absolute ethanol under the action of ultrasonic waves (power 70w, frequency 40Khz), and add 0.3g 2-(perfluorooctyl)ethyl methacrylate (PFOEMA) monomer, Stir at room temperature and set aside; dissolve 0.16g sodium hydroxide in 20mL aqueous solution, and add 4mL of hydrazine hydrate with a mass fraction of 80% to prepare a precipitate; slowly drop the precipitate into the above standby solution and stir at room temperature 30min, then move the mixed solution into a 100mL reactor lined with polytetrafluoroethylene and react at 150°C for 12h. After cooling to room temperature, centrifuge and wash to remove impurities to obtain the composite deacidification material Mg(OH ) ₂ @PPFOEMA, the mass fraction of magnesium hydroxide in the solid composite deacidification material is 70 to 75%.

Example 4

Dissolve 0.429g magnesium acetate tetrahydrate in 20mL absolute ethanol under the action of ultrasonic waves (power 70w, frequency 40Khz), and add 0.4g 2-(perfluorooctyl)ethyl methacrylate (PFOEMA) monomer, Stir at room temperature and set aside; dissolve 0.16g sodium hydroxide in 20mL aqueous solution, and add 4mL of hydrazine hydrate with a mass fraction of 80% to prepare a precipitate; slowly drop the precipitate into the above standby solution and stir at room temperature 30min, then move the mixed solution into a 100mL reactor lined with polytetrafluoroethylene and react at 150°C for 12h. After cooling to room temperature, centrifuge and wash to remove impurities to obtain the composite deacidification material Mg(OH ) ₂ @PPFOEMA, the mass fraction of magnesium hydroxide in the solid composite deacidification material is 60 to 65%.

Example 5

Dissolve 0.429g magnesium acetate tetrahydrate in 20mL absolute ethanol under the action of ultrasonic waves (power 70w, frequency 40Khz), and add 0.5g 2-(perfluorooctyl)ethyl methacrylate (PFOEMA) monomer, Stir at room temperature and set aside; dissolve 0.16g sodium hydroxide in 20mL aqueous solution, and add 4mL of hydrazine hydrate with a mass fraction of 80% to prepare a precipitate; slowly drop the precipitate into the above standby solution and stir at room temperature 30min, then move the mixed solution into a 100mL reactor lined with polytetrafluoroethylene and react at 150°C for 12h. After cooling to room temperature, centrifuge and wash to remove impurities to obtain the composite deacidification material Mg(OH ) ₂ @PPFOEMA, the mass fraction of magnesium hydroxide in the solid composite deacidification material is 50 to 55%.

Example 6

Dissolve 0.429g magnesium acetate tetrahydrate in 20mL absolute ethanol under the action of ultrasonic waves (power 70w, frequency 40Khz), and add 0.2g perfluorocyclohexyl methacrylate (PFCHMA) monomer, stir at room temperature and set aside; Dissolve 0.16g sodium hydroxide in 20mL aqueous solution, and add 4mL of hydrazine hydrate with a mass fraction of 80% to prepare a precipitate; slowly drop the precipitate into the above standby solution and stir at room temperature for 30 minutes, and then mix The solution was moved into a 100mL reaction kettle lined with polytetrafluoroethylene and reacted at 150°C for 12 hours. After cooling to room temperature, it was centrifuged and washed to remove impurities to obtain the composite deacidification material Mg(OH) ₂ @PPFCHMA(PPFCHMA Represents perfluorocyclohexyl methacrylate polymer), in which the mass fraction of magnesium hydroxide in the solid composite deacidification material is 80 to 85%.

Example 7

Dissolve 0.429g magnesium acetate tetrahydrate in 20mL absolute ethanol under the action of ultrasonic waves (power 70w, frequency 40Khz), and add 0.2g (N-methylperfluorohexanesulfonamide) ethyl methacrylate (C ₆ SA) monomer, stir at room temperature and set aside; dissolve 0.16g sodium hydroxide in 20 mL aqueous solution, and add 4 mL of hydrazine hydrate with a mass fraction of 80% to prepare a precipitate; slowly drip the precipitate into the above set aside The solution was stirred at room temperature for 30 minutes, and then the mixed solution was moved into a 100 mL reaction kettle lined with polytetrafluoroethylene and reacted at 150°C for 12 hours. After cooling to room temperature, it was centrifuged and washed to remove impurities to obtain a composite. Deacidification material Mg(OH) ₂ @PC ₆ SA (PC ₆ SA represents methacrylic acid (N-methylperfluorohexanesulfonamide) ethyl ester polymer), in which magnesium hydroxide is in the solid composite deacidification material The mass fraction in is 80~85%.

Example 8

Dissolve 0.429g magnesium acetate tetrahydrate in 20mL absolute ethanol under the action of ultrasonic waves (power 70w, frequency 40Khz), and add 0.2g perfluoroalkyl ethyl acrylate (TEAc-8) monomer, stir at room temperature and set aside. ; Dissolve 0.16g sodium hydroxide in 20mL aqueous solution, and add 4mL of hydrazine hydrate with a mass fraction of 80% to prepare a precipitate; slowly drip the precipitate into the above standby solution and stir at room temperature for 30min, and then add the The mixed solution was moved into a 100mL reactor lined with polytetrafluoroethylene and reacted at 150°C for 12 hours. After cooling to room temperature, it was centrifuged and washed to remove impurities to obtain the composite deacidification material Mg(OH) ₂ @PTEAc- 8 (PTEAc-8 represents perfluoroalkyl ethyl acrylate polymer), in which the mass fraction of magnesium hydroxide in the solid composite deacidification material is 80 to 85%.

Example 9

Dissolve 0.429g magnesium acetate tetrahydrate in 20mL absolute ethanol under the action of ultrasonic waves (power 70w, frequency 40Khz), and add 0.2g trifluoroethyl methacrylate (FMA) monomer, stir at room temperature and set aside; Dissolve 0.16g sodium hydroxide in 20mL aqueous solution, and add 4mL of hydrazine hydrate with a mass fraction of 80% to prepare a precipitate; slowly drip the precipitate into the above standby solution and stir at room temperature for 30 minutes, and then add the mixed solution Move it into a 100mL reaction kettle lined with polytetrafluoroethylene and react at 150°C for 12 hours. After cooling to room temperature, centrifuge and wash to remove impurities to obtain the composite deacidification material Mg(OH) ₂ @PFMA (PFMA is Trifluoroethyl methacrylate polymer), in which the mass fraction of magnesium hydroxide in the solid composite deacidification material is 80 to 85%.

Example 10

Dissolve 0.316g calcium acetate in 20mL absolute ethanol under the action of ultrasonic waves (power 70w, frequency 40Khz), and add 0.1g 2-(perfluorooctyl)ethyl methacrylate (PFOEMA) monomer at room temperature. Stir and set aside; dissolve 0.16g sodium hydroxide in 20mL aqueous solution, and add 4mL of hydrazine hydrate with a mass fraction of 80% to prepare a precipitate; slowly drop the precipitate into the above standby solution and stir at room temperature for 30 minutes. The mixed solution was then moved into a 100 mL reactor lined with polytetrafluoroethylene and reacted at 150°C for 12 hours. After cooling to room temperature, it was centrifuged and washed to remove impurities to obtain the composite deacidification material Ca(OH) ₂ @PPFOEMA, the mass fraction of calcium hydroxide in the solid composite deacidification material is 90 to 95%.

Example 11

Dissolve 0.316g calcium acetate in 20mL absolute ethanol under the action of ultrasonic waves (power 70w, frequency 40Khz), and add 0.2g 2-(perfluorooctyl)ethyl methacrylate (PFOEMA) monomer at room temperature. Stir and set aside; dissolve 0.16g sodium hydroxide in 20mL aqueous solution, and add 4mL of hydrazine hydrate with a mass fraction of 80% to prepare a precipitate; slowly drop the precipitate into the above standby solution and stir at room temperature for 30 minutes. The mixed solution was then moved into a 100 mL reactor lined with polytetrafluoroethylene and reacted at 150°C for 12 hours. After cooling to room temperature, it was centrifuged and washed to remove impurities to obtain the composite deacidification material Ca(OH) ₂ @PPFOEMA, the mass fraction of calcium hydroxide in the solid composite deacidification material is 80 to 85%.

Example 12

Dissolve 0.316g calcium acetate in 20mL absolute ethanol under the action of ultrasonic waves (power 70w, frequency 40Khz), and add 0.3g 2-(perfluorooctyl)ethyl methacrylate (PFOEMA) monomer at room temperature. Stir and set aside; dissolve 0.16g sodium hydroxide in 20mL aqueous solution, and add 4mL of hydrazine hydrate with a mass fraction of 80% to prepare a precipitate; slowly drop the precipitate into the above standby solution and stir at room temperature for 30 minutes. The mixed solution was then moved into a 100 mL reactor lined with polytetrafluoroethylene and reacted at 150°C for 12 hours. After cooling to room temperature, it was centrifuged and washed to remove impurities to obtain the composite deacidification material Ca(OH) ₂ @PPFOEMA, the mass fraction of calcium hydroxide in the solid composite deacidification material is 70 to 75%.

Example 13

Dissolve 0.316g calcium acetate in 20mL absolute ethanol under the action of ultrasonic waves (power 70w, frequency 40Khz), and add 0.4g 2-(perfluorooctyl)ethyl methacrylate (PFOEMA) monomer at room temperature. Stir and set aside; dissolve 0.16g sodium hydroxide in 20mL aqueous solution, and add 4mL of hydrazine hydrate with a mass fraction of 80% to prepare a precipitate; slowly drop the precipitate into the above standby solution and stir at room temperature for 30 minutes. The mixed solution was then moved into a 100 mL reactor lined with polytetrafluoroethylene and reacted at 150°C for 12 hours. After cooling to room temperature, it was centrifuged and washed to remove impurities to obtain the composite deacidification material Ca(OH) ₂ @PPFOEMA, the mass fraction of calcium hydroxide in the solid composite deacidification material is 60 to 65%.

Example 14

Dissolve 0.316g calcium acetate in 20mL absolute ethanol under the action of ultrasonic waves (power 70w, frequency 40Khz), and add 0.5g 2-(perfluorooctyl)ethyl methacrylate (PFOEMA) monomer at room temperature. Stir and set aside; dissolve 0.16g sodium hydroxide in 20mL aqueous solution, and add 4mL of hydrazine hydrate with a mass fraction of 80% to prepare a precipitate; slowly drop the precipitate into the above standby solution and stir at room temperature for 30 minutes. The mixed solution was then moved into a 100 mL reactor lined with polytetrafluoroethylene and reacted at 150°C for 12 hours. After cooling to room temperature, it was centrifuged and washed to remove impurities to obtain the composite deacidification material Ca(OH) ₂ @PPFOEMA, the mass fraction of calcium hydroxide in the solid composite deacidification material is 50 to 55%.

Example 15

Take 1.0g Mg(OH) ₂ @PPFOEMA in Example 2 and disperse it evenly in 200mL perfluorooctane, and treat it with ultrasonic (power 70w, frequency 40Khz) for 30 minutes to obtain a highly stable suspended and dispersed composite deacidification material - perfluorooctane. alkane dispersion system.

Figure 2 shows the infrared spectra of magnesium hydroxide (a), Mg(OH) ₂ @PPFOEMA composite deacidification material (b), and 2-(perfluorooctyl)ethyl methacrylate monomer (c). The absorption peak at 3700cm ^-1 in magnesium hydroxide (a) corresponds to -OH vibration absorption; 1241cm ^-1 , 1205cm ^-1 and 1149cm ^-1 in 2-(perfluorooctyl)ethyl methacrylate (c) The absorption peak at 1725cm -1 corresponds to _-CF2 vibration absorption, the absorption peak at 1725cm ^-1 corresponds to -C=O vibration absorption, and the absorption peak at 1639cm ^-1 corresponds to C=C vibration absorption. Mg(OH) ₂ @PPFOEMA composite deacidification material (b) has both the -OH vibration absorption peak at 3700cm ^-1 and the -CF ₂ vibration absorption peak at 1241cm ^-1 , 1205cm ^-1 , and 1149cm ^-1 , but they do not appear. The vibration absorption peak of C=C at 1639cm ^-1 indicates that CH ₂ =C- in 2-(perfluorooctyl)ethyl methacrylate has undergone a polymerization reaction to form -(CH ₂ -C-) _n -polymer; and, the C=O absorption peak in the infrared spectrum of the composite deacidification material shifts from 1725cm ^-1 to 1735cm ^-1 , indicating that 2-(perfluorooctyl)ethyl methacrylate polymer coating On the surface of magnesium hydroxide, there is a certain interaction between the two, forming a stable core-shell structure composite deacidification material Mg(OH) ₂ @PPFOEMA. The composite deacidification material can be suspended and dispersed in perfluorooctane with high stability, and its stable suspension and dispersion time is not less than 10 days. The optical photo of the sample is shown in Figure 3A.

Comparative example 1

Dissolve 0.429g magnesium acetate tetrahydrate in 20mL absolute ethanol under the action of ultrasonic waves (power 70w, frequency 40Khz) and stir at room temperature before use; dissolve 0.16g sodium hydroxide in 20mL aqueous solution, and add 4mL mass fraction to it Prepare a precipitate for 80% hydrazine hydrate; slowly drop the precipitate into the above standby solution and stir at room temperature for 30 minutes. Then move the mixed solution into a 100 mL reaction kettle lined with polytetrafluoroethylene and incubate at 150°C. React for 12 hours, wait for it to cool to room temperature, then centrifuge and wash to remove impurities to obtain pure Mg(OH) ₂ ; disperse 1.0g Mg(OH) ₂ in 200 mL of perfluorooctane, sonicate for 30 min, and then let stand for 30 min. Afterwards, the Mg(OH) ₂ in it underwent obvious sedimentation, and its optical photo is shown in Figure 3B.

Comparative example 2

Dissolve 0.429g magnesium acetate tetrahydrate in 20mL absolute ethanol under the action of ultrasonic waves (power 70w, frequency 40Khz), and add 0.2g sodium dodecyl sulfate (SDS) monomer, stir at room temperature and set aside; add 0.16 g of sodium hydroxide was dissolved in 20 mL of aqueous solution, and 4 mL of hydrazine hydrate with a mass fraction of 80% was added to prepare a precipitate; the precipitate was slowly dropped into the above standby solution and stirred at room temperature for 30 min, and then the mixed solution was transferred into In a 100mL reaction kettle lined with polytetrafluoroethylene, react at 150°C for 12 hours. After cooling to room temperature, centrifuge and wash to remove impurities to obtain the composite deacidification material Mg(OH) ₂ @SDS; add 1.0g Mg(OH) ₂ @SDS was evenly dispersed in 200 mL of perfluorooctane, dispersed ultrasonically for 30 minutes, and then allowed to stand for 30 minutes before the solid particles settled significantly.

Example 16

Dissolve 0.316g calcium acetate in 20mL absolute ethanol under the action of ultrasonic waves (power 70w, frequency 40Khz), and add 0.2g perfluorocyclohexyl methacrylate (PFCHMA) monomer, stir at room temperature and set aside; add 0.16 g of sodium hydroxide was dissolved in 20 mL of aqueous solution, and 4 mL of hydrazine hydrate with a mass fraction of 80% was added to prepare a precipitate; the precipitate was slowly dropped into the above standby solution and stirred at room temperature for 30 min, and then the mixed solution was transferred into In a 100mL reaction kettle lined with polytetrafluoroethylene, react at 150°C for 12 hours. After cooling to room temperature, centrifuge and wash to remove impurities to obtain the composite deacidification material Ca(OH) ₂ @PPFCHMA. Add 1.0g Ca(OH) ₂ @PPFCHMA was uniformly dispersed in 200 mL of perfluorocyclic ether, and ultrasonic treatment was performed for 30 minutes to obtain a highly stable suspended and dispersed composite deacidification material-perfluorocyclic ether dispersion system.

Example 17

Dissolve 0.429g magnesium acetate tetrahydrate in 20mL absolute ethanol under the action of ultrasonic waves (power 70w, frequency 40Khz), and add 0.2g perfluorocyclohexyl methacrylate (PFCHMA) monomer, stir at room temperature and set aside; Dissolve 0.16g sodium hydroxide in 20mL aqueous solution, and add 4mL of hydrazine hydrate with a mass fraction of 80% to prepare a precipitate; slowly drop the precipitate into the above standby solution and stir at room temperature for 30 minutes, and then mix The solution was moved into a 100mL reaction kettle lined with polytetrafluoroethylene and reacted at 150°C for 12 hours. After cooling to room temperature, it was centrifuged and washed to remove impurities to obtain the composite deacidification material Mg(OH) ₂ @PPFCHMA. 1.0g Mg(OH) ₂ @PPFCHMA was evenly dispersed in 200 mL of perfluorocyclic ether, and ultrasonic treatment was performed for 30 minutes to obtain a highly stable suspended and dispersed composite deacidification material-perfluorocyclic ether dispersion system.

Example 18

The composite deacidification material in Example 15 is used for paper deacidification. At this time, the concentration of the composite deacidification material in the composite deacidification material-perfluorooctane dispersion system is 5g/L.

Take the acidic paper with an average surface pH value of 4.02, soak it in the perfluorooctane medium containing the composite deacidification material Mg(OH) ₂ @PPFOEMA, gently swing the paper with tweezers, soak it for 30 minutes, take out the paper, and dry it at room temperature. Dry for 24h. The surface pH value of the paper treated with the composite deacidification material Mg(OH) ₂ @PPFOEMA was tested using the national standard GB/T 1545.2-2003 method to be 7.56, while the alkali reserve was 466.29mmol/kg (see Table 1), indicating that the The paper treated with the composite deacidification material is still weakly alkaline even with high alkali reserves.

The above deacidified paper was then dry-heat aged at 105°C for 72 hours. The pH value of the paper tested using the national standard GB/T1545.2-2003 method is 7.49, and the alkali reserve is 456.87mmol/kg, indicating that the paper after deacidification and dry heat aging treatment still has a high alkali reserve and Still slightly alkaline. In comparison, the average pH value of paper without deacidification treatment after dry heat aging treatment was 3.69, indicating that the paper treated with the composite deacidification material Mg(OH) ₂ @PPFOEMA material has better deacidification effect and Anti-acid reflux ability.

The hydrophobicity (water contact angle) of the paper before and after the above-mentioned deacidification treatment and the dry-heat aging paper after the deacidification treatment was measured. The measured data are shown in Figure 5 and Table 1.

It can be seen from Figure 5 that the contact angle of paper without deacidification with water dropped sharply from the initial 117° to 25° within 10 minutes, but after deacidification and dry heat aging The contact angle between the treated paper and water was 138° and remained basically unchanged within 20 minutes, indicating that the paper treated with the composite deacidification material showed excellent hydrophobicity.

The mechanical properties (folding resistance, tensile strength and tearing strength) of the paper before and after the above-mentioned deacidification treatment and the dry-heat aged paper before and after the deacidification treatment were measured. The data are shown in Table 1. The results show that the mechanical properties of paper treated with the composite deacidification material Mg(OH) ₂ @PPFOEMA are improved to a certain extent compared with untreated paper. Even after dry heat aging treatment, its mechanical properties are still better than those without deacidification. Handled paper.

Table 1 Performance data of paper samples

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims (8)

1. A method for preparing a composite deacidification material with high alkali reserve and hydrophobicity after deacidification treatment of paper, characterized in that the steps are as follows: 1) Add hydrazine hydrate aqueous solution to the sodium hydroxide aqueous solution to obtain a precipitant solution; 2) Prepare an ethanol solution containing calcium, magnesium ions and fluoroalkyl methacrylate; 3) Mix and stir the solution in steps 1) and 2), place it in a reaction kettle, control the temperature at 150°C, and react for 12 hours; 4) The reacted mixture is centrifuged, washed, and dried to obtain a solid composite deacidification material. 2. The method for making a composite deacidification material with high alkali reserve and hydrophobicity after deacidification treatment of paper according to claim 1, characterized in that the alkaline compound in the solid composite deacidification material is magnesium hydroxide. , any one of calcium hydroxide. 3. The method for making a composite deacidification material with high alkali reserve and hydrophobicity after deacidification of paper according to claim 1, characterized in that the mass fraction of the alkaline compound in the solid composite deacidification material is 50 ~95%. 4. A composite deacidification material obtained by the method of any one of claims 1 to 3, which enables the paper to have high alkali reserve and hydrophobicity after deacidification treatment. 5. The composite deacidification material according to claim 4, which allows the paper to have high alkali reserve and hydrophobicity after deacidification treatment, is used for paper deacidification. 6. The application according to claim 5, characterized in that the composite deacidification material is first dispersed in a fluorocarbon medium and ultrasonic treated for 30 minutes to obtain a stable suspension, and then used for paper deacidification. 7. Application according to claim 6, characterized in that the fluorocarbon medium is perfluorooctane, perfluoroheptane, perfluorononane, perfluorobutyltetrahydrofuran, perfluorocyclic ether, perfluorocarbon One or more of cyclohexane, perfluoromethylcyclohexane, perfluorotoluene, and perfluoro-2,7-dimethyloctane. 8. The application according to claim 6, characterized in that the specific steps are: (1) Disperse the composite deacidification material in the fluorocarbon medium, and prepare a suspension after ultrasonic treatment for 30 minutes. The concentration of the composite deacidification material is 3.0 to 10.0g/L; (2) Soak the paper to be deacidified in the suspension obtained in step (1), soak for 30 minutes, and then dry at room temperature to complete the paper deacidification treatment.