Preparation method of porous nano calcium carbonate filler

Abstract

The invention discloses a preparation method of a porous nano calcium carbonate filler. The preparation method comprises the following steps: (1) preparing an additive solution I; (2) preparing an additive solution II; (3) preparing an adding solution III; and (4) uniformly mixing a calcium salt solution, the additive solution I, the additive solution II and the additive solution III, then adding a carbonate solution in a stirring state, rapidly stirring until no precipitate is generated after material adding is completed, then carrying out solid-liquid separation, washing a solid phase with deionized water, washing with ethanol, and drying to obtain the porous nano calcium carbonate filler. The nano calcium carbonate filler prepared through the method is of a porous structure, good in dispersity and high in specific surface area, and the performance of a composite material can be remarkably improved when the nano calcium carbonate filler serves as the filler.

Description

Technical Field

[0001] The present invention relates to the technical field of nano calcium carbonate fillers, and particularly relates to a preparation method of porous nano calcium carbonate fillers. Background Art

[0002] Nano calcium carbonate fillers are nano-scale calcium carbonate particles. Their high specific surface area enables them to enhance the interaction with matrix materials, improving the strength, hardness and wear resistance of composite materials; their high activity makes them easy to be surface modified. They are widely used in fields such as plastics, rubber, coatings, papermaking and the pharmaceutical industry, and with the continuous improvement of preparation and modification technologies, their market prospects are becoming increasingly broad.

[0003] There are various preparation methods for nano calcium carbonate fillers, mainly including carbonization method, co-precipitation method, microemulsion method, sol-gel method, hydrothermal method, etc. Among them, the co-precipitation method refers to adding a suitable precipitant to an electrolyte solution, and then reacting to form a precipitate with small particle size and uniform dispersion. This method is deeply loved by material preparers because of its simple principle and convenient operation. Summary of the Invention

[0004] Therefore, the present invention provides a preparation method of porous nano calcium carbonate fillers, which comprises the following steps:

[0005] (1) Prepare an aqueous solution of tannic acid and an aqueous solution of 4-chlorobutyric acid; keep the aqueous solution of tannic acid at a constant temperature of 50±5°C in a water bath, stir the aqueous solution of tannic acid, add an aqueous solution of sodium acetate to the solution under stirring, continue stirring for more than 20 min after the addition is completed, then add the aqueous solution of 4-chlorobutyric acid under stirring, continue stirring at 50±5°C for more than 2 h after the addition is completed, then add an aqueous solution of sodium hydroxide, heat up to 60±5°C after the addition is completed, keep stirring at a constant temperature for more than 3 h after reaching the temperature, air-cool to room temperature after the heat preservation is over, and adjust the pH to neutral to obtain additive solution I;

[0006] (2) Prepare a mixed aqueous solution of acid-type sophorolipid, ethanol and glycerol; heat the mixed aqueous solution of acid-type sophorolipid, ethanol and glycerol to 70±5°C in a water bath for heat preservation, perform condensation reflux during the heat preservation process, then add p-toluenesulfonic acid under stirring, continue stirring at 70±5°C for 2-3 h after the addition is completed, naturally cool to room temperature after the stirring is over, add sodium lauroyl sarcosinate, and continue stirring for more than 30 min after the addition is completed to obtain additive solution II;

[0007] (3) Add bovine serum albumin to deionized water, stir for more than 20 min, then add hydrogen peroxide to the solution under stirring. After the addition is completed, stir for more than 20 min, then place it in an environment of 4 - 5 °C and let it stand for more than 10 h. Then add glucose, stir for more than 10 min after the addition, heat to 90 ± 5 °C, keep stirring for more than 2 h during the heat preservation process with condensation reflux, and then naturally cool to room temperature to obtain Additive Solution III;

[0008] (4) Mix the calcium salt solution, the Additive Solution I, Additive Solution II and Additive Solution III evenly, then add the carbonate solution under stirring. After the addition is completed, stir rapidly until no more precipitation occurs, then perform solid-liquid separation. Wash the solid phase with deionized water more than 3 times, then wash it with ethanol more than 3 times, and dry it to obtain the porous nano calcium carbonate filler.

[0009] Further, in the step (1), in the aqueous solution of tannic acid, the concentration of tannic acid is 30 - 40 g / L, and the solvent is water; in the aqueous solution of 4-chlorobutyric acid, the concentration of 4-chlorobutyric acid is 10 - 15 g / L, and the solvent is water; in the aqueous solution of sodium acetate, the concentration of sodium acetate is 60 - 70 g / L, and the solvent is water; in the aqueous solution of sodium hydroxide, the mass percentage of sodium hydroxide is 20%, and the solvent is water; the mixing volume ratio of the aqueous solution of tannic acid, the aqueous solution of 4-chlorobutyric acid, the aqueous solution of sodium acetate and the aqueous solution of sodium hydroxide is Aqueous solution of tannic acid: Aqueous solution of 4-chlorobutyric acid: Aqueous solution of sodium acetate: Aqueous solution of sodium hydroxide = 10:3 - 5:1 - 2:1 - 2.

[0010] Further, in the step (2), in the mixed aqueous solution of acid-type sophorolipid, ethanol and glycerol, the concentration of acid-type sophorolipid is 10 - 15 g / L, the volume percentage of ethanol is 40% - 50%, the volume percentage of glycerol is 5% - 8%, and the solvent is water; the amounts of p-toluenesulfonic acid and sodium dodecylsarcosinate added are in a volume ratio to the mixed aqueous solution of acid-type sophorolipid, ethanol and glycerol as p-Toluenesulfonic acid: Sodium dodecylsarcosinate: Mixed aqueous solution of acid-type sophorolipid, ethanol and glycerol = 2 - 3 g:8 - 10 g:1 L.

[0011] Further, in the step (3), the amount ratio of bovine serum albumin added to deionized water is Bovine serum albumin: Deionized water = 2 - 2.5 g:100 mL; the addition amounts of hydrogen peroxide and glucose to the addition amount of bovine serum albumin are in a ratio of Hydrogen peroxide: Glucose: Bovine serum albumin = 0.6 - 0.8 mL:1 - 1.4 g:2 - 2.5 g; wherein the mass percentage of the solute in the hydrogen peroxide is 10%.

[0012] Further, in the step (4), the volume ratio of the calcium salt solution, the additive solution I, the additive solution II, the additive solution III, and the carbonate solution is calcium salt solution: additive solution I: additive solution II: additive solution III: carbonate solution = 50:2 - 3:2 - 3:2 - 3:50; wherein the calcium salt solution is an aqueous solution of a soluble calcium salt, and the concentration of calcium ions is 0.4 - 0.5 mol / L; wherein the carbonate solution is an aqueous solution of a soluble carbonate, and the concentration of carbonate ions is 0.4 - 0.5 mol / L.

[0013] The beneficial effects of the present invention are as follows: The nano-calcium carbonate filler prepared by the method of the present invention has a porous structure and good dispersibility, manifested as a relatively high specific surface area. As a filler, it can significantly improve the performance of the composite material. By adding the additive solution of the present invention, the specific surface area of the filler can be significantly increased. The main reason may be that: First, the present invention carboxylates tannic acid, grafts carboxyl groups to some of the hydroxyl groups on the surface of tannic acid, increases the content of carboxyl groups on the surface of tannic acid, and then improves the adsorption of tannic acid on calcium carbonate. After the calcium carbonate crystal nuclei are formed, the modified tannic acid macromolecules are easily adsorbed on the surface of the crystal nuclei, inhibiting the growth of the crystal nuclei, playing a role in refining the crystal grains and increasing the specific surface area. At the same time, the growth of some parts of the crystal nucleus surface is slow due to adsorption, resulting in more pores in the final crystal. Sophorolipid undergoes an esterification reaction with small molecule alcohols under the action of p-toluenesulfonic acid, which can significantly improve the performance of sophorolipid as a surfactant and is also beneficial to the refinement of crystal grains and the formation of pores. Bovine serum albumin is first oxidized and then glycosylated with glucose, which can effectively improve the dispersibility of crystal nuclei, prevent agglomeration, reduce the particle size, and increase the specific surface area. Detailed implementation manners

[0014] The following further illustrates the present invention with reference to examples.

[0015] Example 1

[0016] A preparation method of a porous nano-calcium carbonate filler comprises the following steps:

[0017] (1) Prepare an aqueous solution of tannic acid and an aqueous solution of 4-chlorobutyric acid. In the aqueous solution of tannic acid, the concentration of tannic acid is 30 g / L and the solvent is water. In the aqueous solution of 4-chlorobutyric acid, the concentration of 4-chlorobutyric acid is 10 g / L and the solvent is water. Keep the aqueous solution of tannic acid in a water bath at a constant temperature of 50 °C and stir it. While stirring, add an aqueous solution of sodium acetate to the solution. After the addition is complete, continue stirring for 20 min. Then, while stirring, add the aqueous solution of 4-chlorobutyric acid. After the addition is complete, continue stirring and keeping warm at 50 °C for 2 h. Then, add an aqueous solution of sodium hydroxide. In the aqueous solution of sodium acetate, the concentration of sodium acetate is 60 g / L and the solvent is water. In the aqueous solution of sodium hydroxide, the mass percentage of sodium hydroxide is 20% and the solvent is water. The mixing volume ratio of the aqueous solution of tannic acid, the aqueous solution of 4-chlorobutyric acid, the aqueous solution of sodium acetate, and the aqueous solution of sodium hydroxide is aqueous solution of tannic acid : aqueous solution of 4-chlorobutyric acid : aqueous solution of sodium acetate : aqueous solution of sodium hydroxide = 10:3:1:1. After the addition is complete, raise the temperature to 60 °C. After reaching the temperature, keep stirring for 3 h. After the heat preservation is over, air-cool to room temperature and adjust the pH to neutral to obtain additive solution I.

[0018] (2) Prepare a mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol. In the mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol, the concentration of acid-type sophorolipid is 10 g / L, the volume percentage of ethanol is 40%, the volume percentage of glycerol is 5%, and the solvent is water. Heat the mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol in a water bath to 70 °C and keep it warm. During the heat preservation process, carry out condensation reflux. Then, while stirring, add p-toluenesulfonic acid. After the addition is complete, continue stirring and keeping warm at 70 °C for 2 h. After the stirring is over, naturally cool to room temperature and add sodium lauroyl sarcosinate. The addition amounts of p-toluenesulfonic acid and sodium lauroyl sarcosinate and the volume ratio of the mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol are p-toluenesulfonic acid : sodium lauroyl sarcosinate : mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol = 2 g:8 g:1 L. After the addition is complete, continue stirring for 30 min to obtain additive solution II.

[0019] (3) Add bovine serum albumin to deionized water. The addition ratio of bovine serum albumin to deionized water is bovine serum albumin : deionized water = 2 g : 100 mL. Stir for 20 min. Then, while stirring, add hydrogen peroxide to the solution. After the addition is complete, stir for 20 min. Then, place it in an environment at 5 °C and let it stand for 10 h. Then, add glucose. The addition amounts of hydrogen peroxide and glucose and the addition ratio of bovine serum albumin are hydrogen peroxide : glucose : bovine serum albumin = 0.6 mL : 1 g : 2 g. Among them, the mass percentage of the solute in the hydrogen peroxide is 10%. After the addition, stir for 10 min and heat to 90 °C. After reaching the temperature, keep stirring for 2 h. During the heat preservation process, carry out condensation reflux. Then, naturally cool to room temperature to obtain additive solution III.

[0020] (4) Mix the calcium chloride solution, the additive solution I, the additive solution II, and the additive solution III evenly, and then add the ammonium carbonate solution under stirring. The volume ratio of the calcium chloride solution, the additive solution I, the additive solution II, the additive solution III, and the ammonium carbonate solution is calcium chloride solution: additive solution I: additive solution II: additive solution III: ammonium carbonate solution = 50:2:2:2:50; wherein in the calcium chloride solution, the concentration of calcium ions is 0.4 mol / L; wherein in the ammonium carbonate solution, the concentration of carbonate ions is 0.4 mol / L; after the feeding is completed, stir rapidly until no more precipitation occurs, then perform solid-liquid separation. Wash the solid phase 3 times with deionized water, then wash it 3 times with ethanol, and dry it at 110 °C for 2 h to obtain the porous nano calcium carbonate filler.

[0021] Example 2

[0022] A preparation method of a porous nano calcium carbonate filler, comprising the following steps:

[0023] (1) Prepare an aqueous solution of tannic acid and an aqueous solution of 4-chlorobutyric acid; in the aqueous solution of tannic acid, the concentration of tannic acid is 35 g / L and the solvent is water; in the aqueous solution of 4-chlorobutyric acid, the concentration of 4-chlorobutyric acid is 10 g / L and the solvent is water; keep the aqueous solution of tannic acid at a constant temperature of 50 °C in a water bath, stir the aqueous solution of tannic acid, and add the aqueous solution of sodium acetate to the solution under stirring. After the feeding is completed, continue stirring for 20 min, and then add the aqueous solution of 4-chlorobutyric acid under stirring. After the feeding is completed, continue to keep the temperature at 50 °C and stir for 2 h, and then add the aqueous solution of sodium hydroxide. In the aqueous solution of sodium acetate, the concentration of sodium acetate is 60 g / L and the solvent is water; in the aqueous solution of sodium hydroxide, the mass percentage of sodium hydroxide is 20% and the solvent is water; the volume ratio of the aqueous solution of tannic acid, the aqueous solution of 4-chlorobutyric acid, the aqueous solution of sodium acetate, and the aqueous solution of sodium hydroxide is aqueous solution of tannic acid: aqueous solution of 4-chlorobutyric acid: aqueous solution of sodium acetate: aqueous solution of sodium hydroxide = 10:4:1:1; after the feeding is completed, raise the temperature to 60 °C, keep the temperature constant and stir for 3 h after reaching the temperature, air-cool to room temperature after the heat preservation is completed, and adjust the pH to neutral to obtain the additive solution I;

[0024] (2) Prepare an aqueous mixed solution of acid-type sophorolipid, ethanol, and glycerol. In the aqueous mixed solution of acid-type sophorolipid, ethanol, and glycerol, the concentration of acid-type sophorolipid is 12 g / L, the volume percentage of ethanol is 40%, the volume percentage of glycerol is 6%, and the solvent is water. Heat the aqueous mixed solution of acid-type sophorolipid, ethanol, and glycerol in a water bath to 70 °C and keep it warm. During the warming process, carry out condensation reflux. Then, add p-toluenesulfonic acid under stirring. After the addition is completed, continue stirring at 70 °C for 2 h. After the stirring ends, naturally cool to room temperature, and add sodium dodecyl sarcosinate. The addition amounts of p-toluenesulfonic acid and sodium dodecyl sarcosinate are in a volume ratio to the aqueous mixed solution of acid-type sophorolipid, ethanol, and glycerol as follows: p-toluenesulfonic acid:sodium dodecyl sarcosinate:aqueous mixed solution of acid-type sophorolipid, ethanol, and glycerol = 2 g:9 g:1 L. After the addition is completed, continue stirring for 30 min to obtain Additive Solution II;

[0025] (3) Add bovine serum albumin to deionized water. The addition amount ratio of bovine serum albumin to deionized water is bovine serum albumin:deionized water = 2 g:100 mL. Stir for 20 min. Then, add hydrogen peroxide to the solution under stirring. After the addition is completed, stir for 20 min, and then place it in an environment at 5 °C and let it stand for 10 h. Then, add glucose. The addition amounts of hydrogen peroxide and glucose are in a ratio to the addition amount of bovine serum albumin as follows: hydrogen peroxide:glucose:bovine serum albumin = 0.7 mL:1.2 g:2 g. Among them, the mass percentage of the solute in the hydrogen peroxide is 10%. After the addition, stir for 10 min, heat to 90 °C, and keep stirring for 2 h after reaching the temperature. During the warming process, carry out condensation reflux, and then naturally cool to room temperature to obtain Additive Solution III;

[0026] (4) Mix the calcium chloride solution, Additive Solution I, Additive Solution II, and Additive Solution III evenly. Then, add ammonium carbonate solution under stirring. The volume ratio of the calcium chloride solution, Additive Solution I, Additive Solution II, Additive Solution III, and ammonium carbonate solution is calcium chloride solution:Additive Solution I:Additive Solution II:Additive Solution III:ammonium carbonate solution = 50:2:2:2:50. Among them, in the calcium chloride solution, the concentration of calcium ions is 0.4 mol / L. Among them, in the ammonium carbonate solution, the concentration of carbonate ions is 0.4 mol / L. After the addition is completed, quickly stir until no more precipitation occurs, and then carry out solid-liquid separation. Wash the solid phase 3 times with deionized water and then 3 times with ethanol, and dry it at 110 °C for 2 h to obtain the porous nano-calcium carbonate filler.

[0027] Example 3

[0028] A preparation method of a porous nano-calcium carbonate filler, comprising the following steps:

[0029] (1) Prepare an aqueous solution of tannic acid and an aqueous solution of 4-chlorobutyric acid. In the aqueous solution of tannic acid, the concentration of tannic acid is 40 g / L and the solvent is water. In the aqueous solution of 4-chlorobutyric acid, the concentration of 4-chlorobutyric acid is 15 g / L and the solvent is water. Keep the aqueous solution of tannic acid at a constant temperature of 50 °C in a water bath and stir it. While stirring, add an aqueous solution of sodium acetate to the solution. After the addition is complete, continue stirring for 20 min, then add the aqueous solution of 4-chlorobutyric acid while stirring. After the addition is complete, continue stirring and keeping warm at 50 °C for 2 h, then add an aqueous solution of sodium hydroxide. In the aqueous solution of sodium acetate, the concentration of sodium acetate is 70 g / L and the solvent is water. In the aqueous solution of sodium hydroxide, the mass percentage of sodium hydroxide is 20% and the solvent is water. The mixing volume ratio of the aqueous solution of tannic acid, the aqueous solution of 4-chlorobutyric acid, the aqueous solution of sodium acetate, and the aqueous solution of sodium hydroxide is aqueous solution of tannic acid : aqueous solution of 4-chlorobutyric acid : aqueous solution of sodium acetate : aqueous solution of sodium hydroxide = 10 : 4 : 2 : 2. After the addition is complete, raise the temperature to 60 °C. After reaching the temperature, keep stirring for 3 h. After the heat preservation is completed, air-cool to room temperature and adjust the pH to neutral to obtain additive solution I.

[0030] (2) Prepare a mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol. In the mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol, the concentration of acid-type sophorolipid is 14 g / L, the volume percentage of ethanol is 50%, the volume percentage of glycerol is 7%, and the solvent is water. Heat the mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol to 70 °C in a water bath and keep it warm. During the heat preservation process, carry out condensation reflux, then add p-toluenesulfonic acid while stirring. After the addition is complete, continue stirring and keeping warm at 70 °C for 2 h. After the stirring is completed, cool naturally to room temperature and add sodium lauroyl sarcosinate. The amounts of p-toluenesulfonic acid and sodium lauroyl sarcosinate added are in a volume ratio to the mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol of p-toluenesulfonic acid : sodium lauroyl sarcosinate : mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol = 3 g : 9 g : 1 L. After the addition is complete, continue stirring for 30 min to obtain additive solution II.

[0031] (3) Add bovine serum albumin into deionized water. The mass ratio of bovine serum albumin to deionized water is bovine serum albumin: deionized water = 2.5 g: 100 mL. Stir for 20 min, then add hydrogen peroxide into the solution under stirring. After the addition is completed, stir for 20 min, then place it in an environment at 5 °C and let it stand for 10 h. Then add glucose. The addition amounts of hydrogen peroxide and glucose to the addition amount of bovine serum albumin are hydrogen peroxide: glucose: bovine serum albumin = 0.7 mL: 1.2 g: 2.5 g. The mass percentage of the solute in the hydrogen peroxide is 10%. After the addition, stir for 10 min, heat to 90 °C, keep stirring for 2 h after reaching the temperature, and carry out condensation reflux during the heat preservation process. Then cool it naturally to room temperature to obtain the additive solution III.

[0032] (4) Mix the calcium chloride solution, the additive solution I, the additive solution II, and the additive solution III evenly, then add the ammonium carbonate solution under stirring. The volume ratio of the calcium chloride solution, the additive solution I, the additive solution II, the additive solution III, and the ammonium carbonate solution is calcium chloride solution: additive solution I: additive solution II: additive solution III: ammonium carbonate solution = 50:3:3:3:50. In the calcium chloride solution, the concentration of calcium ions is 0.4 mol / L. In the ammonium carbonate solution, the concentration of carbonate ions is 0.4 mol / L. After the addition is completed, stir rapidly until no more precipitation occurs, then carry out solid-liquid separation. Wash the solid phase 3 times with deionized water and then 3 times with ethanol, and dry it at 110 °C for 2 h to obtain the porous nano calcium carbonate filler.

[0033] Example 4

[0034] A preparation method of a porous nano calcium carbonate filler, comprising the following steps:

[0035] (1) Prepare an aqueous solution of tannic acid and an aqueous solution of 4-chlorobutyric acid. In the aqueous solution of tannic acid, the concentration of tannic acid is 40 g / L and the solvent is water. In the aqueous solution of 4-chlorobutyric acid, the concentration of 4-chlorobutyric acid is 15 g / L and the solvent is water. Keep the aqueous solution of tannic acid in a water bath at a constant temperature of 50 °C for heat preservation, stir the aqueous solution of tannic acid, add an aqueous solution of sodium acetate to the solution under stirring, continue stirring for 20 min after the addition is completed, then add the aqueous solution of 4-chlorobutyric acid under stirring, continue stirring at 50 °C for heat preservation for 2 h after the addition is completed, and then add an aqueous solution of sodium hydroxide. In the aqueous solution of sodium acetate, the concentration of sodium acetate is 70 g / L and the solvent is water. In the aqueous solution of sodium hydroxide, the mass percentage of sodium hydroxide is 20% and the solvent is water. The mixing volume ratio of the aqueous solution of tannic acid, the aqueous solution of 4-chlorobutyric acid, the aqueous solution of sodium acetate and the aqueous solution of sodium hydroxide is aqueous solution of tannic acid : aqueous solution of 4-chlorobutyric acid : aqueous solution of sodium acetate : aqueous solution of sodium hydroxide = 10 : 5 : 2 : 2. After the addition is completed, raise the temperature to 60 °C, keep stirring at a constant temperature for 3 h after reaching the temperature, air-cool to room temperature after the heat preservation is completed, adjust the pH to neutral to obtain additive solution I;

[0036] (2) Prepare a mixed aqueous solution of acid-type sophorolipid, ethanol and glycerol. In the mixed aqueous solution of acid-type sophorolipid, ethanol and glycerol, the concentration of acid-type sophorolipid is 15 g / L, the volume percentage of ethanol is 50%, the volume percentage of glycerol is 8%, and the solvent is water. Heat the mixed aqueous solution of acid-type sophorolipid, ethanol and glycerol in a water bath to 70 °C for heat preservation, carry out condensation reflux during the heat preservation process, then add p-toluenesulfonic acid under stirring, continue stirring at 70 °C for 2 h after the addition is completed, naturally cool to room temperature after the stirring is ended, add sodium lauroyl sarcosinate, and the amounts of p-toluenesulfonic acid and sodium lauroyl sarcosinate added are in a volume ratio to the mixed aqueous solution of acid-type sophorolipid, ethanol and glycerol of p-toluenesulfonic acid : sodium lauroyl sarcosinate : mixed aqueous solution of acid-type sophorolipid, ethanol and glycerol = 3 g : 10 g : 1 L. Continue stirring for 30 min after the addition is completed to obtain additive solution II;

[0037] (3) Add bovine serum albumin into deionized water. The mass ratio of bovine serum albumin to deionized water is bovine serum albumin: deionized water = 2.5 g: 100 mL. Stir for 20 min, then add hydrogen peroxide to the solution under stirring. After the addition is completed, stir for another 20 min, then place it in an environment at 5 °C and let it stand for 10 h. Then add glucose. The addition amounts of hydrogen peroxide and glucose to the bovine serum albumin are in the ratio of hydrogen peroxide: glucose: bovine serum albumin = 0.8 mL: 1.4 g: 2.5 g. Among them, the mass percentage of the solute in the hydrogen peroxide is 10%. After the addition, stir for 10 min, heat to 90 °C, keep stirring for 2 h after reaching the temperature, and carry out condensation reflux during the heat preservation process, then cool naturally to room temperature to obtain the additive solution III.

[0038] (4) Mix the calcium chloride solution, the additive solution I, the additive solution II and the additive solution III evenly, then add the ammonium carbonate solution under stirring. The volume ratio of the calcium chloride solution, the additive solution I, the additive solution II, the additive solution III and the ammonium carbonate solution is calcium chloride solution: additive solution I: additive solution II: additive solution III: ammonium carbonate solution = 50:3:3:3:50. Among them, in the calcium chloride solution, the concentration of calcium ions is 0.4 mol / L. Among them, in the ammonium carbonate solution, the concentration of carbonate ions is 0.4 mol / L. After the addition is completed, stir rapidly until no more precipitation occurs, then carry out solid-liquid separation. The solid phase is washed 3 times with deionized water and then 3 times with ethanol, and dried at 110 °C for 2 h to obtain the porous nano calcium carbonate filler.

[0039] Comparative Example 1

[0040] A preparation method of a calcium carbonate filler for comparison includes the following steps:

[0041] (1) Prepare a mixed aqueous solution of acid-type sophorolipid, ethanol and glycerol. In the mixed aqueous solution of acid-type sophorolipid, ethanol and glycerol, the concentration of acid-type sophorolipid is 14 g / L, the volume percentage of ethanol is 50%, the volume percentage of glycerol is 7%, and the solvent is water. Heat the mixed aqueous solution of acid-type sophorolipid, ethanol and glycerol in a water bath to 70 °C and keep it warm. Carry out condensation reflux during the heat preservation process, then add p-toluenesulfonic acid under stirring. After the addition is completed, continue to stir at 70 °C for 2 h. After the stirring ends, cool naturally to room temperature, add sodium dodecyl sarcosinate. The addition amounts of p-toluenesulfonic acid and sodium dodecyl sarcosinate to the mixed aqueous solution of acid-type sophorolipid, ethanol and glycerol are in the ratio of p-toluenesulfonic acid: sodium dodecyl sarcosinate: mixed aqueous solution of acid-type sophorolipid, ethanol and glycerol = 3 g: 9 g: 1 L. After the addition is completed, continue to stir for 30 min to obtain the additive solution II.

[0042] (2) Add bovine serum albumin to deionized water. The mass ratio of bovine serum albumin to deionized water is bovine serum albumin: deionized water = 2.5 g: 100 mL. Stir for 20 min, then add hydrogen peroxide to the solution while stirring. After the addition is complete, stir for another 20 min, then place it in an environment at 5 °C and let it stand for 10 h. Then add glucose. The addition amounts of hydrogen peroxide and glucose to the addition amount of bovine serum albumin are hydrogen peroxide: glucose: bovine serum albumin = 0.7 mL: 1.2 g: 2.5 g. The mass percentage of the solute in the hydrogen peroxide is 10%. Stir for 10 min after the addition, heat to 90 °C, keep stirring for 2 h after reaching the temperature, and carry out condensation reflux during the heat preservation process, then cool naturally to room temperature to obtain the additive solution III.

[0043] (3) Mix the calcium chloride solution, the additive solution II and the additive solution III evenly, then add the ammonium carbonate solution while stirring. The volume ratio of the calcium chloride solution, the additive solution II, the additive solution III and the ammonium carbonate solution is calcium chloride solution: additive solution II: additive solution III: ammonium carbonate solution = 50:3:3:50. In the calcium chloride solution, the concentration of calcium ions is 0.4 mol / L. In the ammonium carbonate solution, the concentration of carbonate ions is 0.4 mol / L. After the addition is complete, stir rapidly until no more precipitation occurs, then carry out solid-liquid separation. Wash the solid phase 3 times with deionized water and then 3 times with ethanol, and dry at 110 °C for 2 h to obtain the calcium carbonate filler of this comparative example.

[0044] Comparative Example 2

[0045] A preparation method of a calcium carbonate filler for comparison includes the following steps:

[0046] (1) Prepare an aqueous solution of tannic acid and an aqueous solution of 4-chlorobutyric acid. In the aqueous solution of tannic acid, the concentration of tannic acid is 40 g / L and the solvent is water. In the aqueous solution of 4-chlorobutyric acid, the concentration of 4-chlorobutyric acid is 15 g / L and the solvent is water. Keep the aqueous solution of tannic acid at a constant temperature of 50 °C in a water bath and stir it. While stirring, add an aqueous solution of sodium acetate to the solution. After the addition is complete, continue stirring for 20 min, then add the aqueous solution of 4-chlorobutyric acid while stirring. After the addition is complete, continue stirring at 50 °C for 2 h, and then add an aqueous solution of sodium hydroxide. In the aqueous solution of sodium acetate, the concentration of sodium acetate is 70 g / L and the solvent is water. In the aqueous solution of sodium hydroxide, the mass percentage of sodium hydroxide is 20% and the solvent is water. The mixing volume ratio of the aqueous solution of tannic acid, the aqueous solution of 4-chlorobutyric acid, the aqueous solution of sodium acetate, and the aqueous solution of sodium hydroxide is aqueous solution of tannic acid : aqueous solution of 4-chlorobutyric acid : aqueous solution of sodium acetate : aqueous solution of sodium hydroxide = 10 : 4 : 2 : 2. After the addition is complete, raise the temperature to 60 °C, and after reaching the temperature, stir at a constant temperature for 3 h. After the heat preservation is completed, air-cool to room temperature, adjust the pH to neutral to obtain Additive Solution I.

[0047] (2) Prepare a mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol. In the mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol, the concentration of acid-type sophorolipid is 14 g / L, the volume percentage of ethanol is 50%, the volume percentage of glycerol is 7%, and the solvent is water. Heat the mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol to 70 °C in a water bath and stir for 2 h. After the stirring is completed, naturally cool to room temperature, and add sodium lauroyl sarcosinate. The amount of sodium lauroyl sarcosinate added is in a volume ratio to the mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol of sodium lauroyl sarcosinate : mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol = 9 g : 1 L. After the addition is complete, continue stirring for 30 min to obtain Additive Solution II of this comparative example.

[0048] (3) Add bovine serum albumin to deionized water. The amount ratio of bovine serum albumin added to deionized water is bovine serum albumin : deionized water = 2.5 g : 100 mL. Stir for 20 min, then add hydrogen peroxide to the solution while stirring. After the addition is complete, stir for 20 min, then place it in an environment at 5 °C and let it stand for 10 h, and then add glucose. The addition amounts of hydrogen peroxide and glucose to the amount of bovine serum albumin are in a ratio of hydrogen peroxide : glucose : bovine serum albumin = 0.7 mL : 1.2 g : 2.5 g. Among them, the mass percentage of the solute in the hydrogen peroxide is 10%. After the addition, stir for 10 min, heat to 90 °C, and after reaching the temperature, stir at a constant temperature for 2 h. During the heat preservation process, carry out condensation reflux, and then naturally cool to room temperature to obtain Additive Solution III.

[0049] (4) Mix the calcium chloride solution, the additive solution I, the additive solution II, and the additive solution III evenly, and then add the ammonium carbonate solution under stirring. The volume ratio of the calcium chloride solution, the additive solution I, the additive solution II, the additive solution III, and the ammonium carbonate solution is calcium chloride solution: additive solution I: additive solution II: additive solution III: ammonium carbonate solution = 50:3:3:3:50. Among them, in the calcium chloride solution, the concentration of calcium ions is 0.4 mol / L. Among them, in the ammonium carbonate solution, the concentration of carbonate ions is 0.4 mol / L. After the feeding is completed, stir rapidly until no more precipitation occurs, then perform solid-liquid separation. Wash the solid phase with deionized water 3 times, then wash it with ethanol 3 times, and dry it at 110 °C for 2 h to obtain the calcium carbonate filler of this comparative example.

[0050] Comparative Example 3

[0051] A preparation method of a calcium carbonate filler for comparison includes the following steps:

[0052] (1) Prepare an aqueous solution of tannic acid and an aqueous solution of 4-chlorobutyric acid. In the aqueous solution of tannic acid, the concentration of tannic acid is 40 g / L, and the solvent is water. In the aqueous solution of 4-chlorobutyric acid, the concentration of 4-chlorobutyric acid is 15 g / L, and the solvent is water. Keep the aqueous solution of tannic acid at a constant temperature of 50 °C in a water bath, stir the aqueous solution of tannic acid, and add the aqueous solution of sodium acetate to the solution under stirring. After the feeding is completed, continue stirring for 20 min, and then add the aqueous solution of 4-chlorobutyric acid under stirring. After the feeding is completed, continue to stir at 50 °C for 2 h, and then add the aqueous solution of sodium hydroxide. In the aqueous solution of sodium acetate, the concentration of sodium acetate is 70 g / L, and the solvent is water. In the aqueous solution of sodium hydroxide, the mass percentage of sodium hydroxide is 20%, and the solvent is water. The mixing volume ratio of the aqueous solution of tannic acid, the aqueous solution of 4-chlorobutyric acid, the aqueous solution of sodium acetate, and the aqueous solution of sodium hydroxide is aqueous solution of tannic acid: aqueous solution of 4-chlorobutyric acid: aqueous solution of sodium acetate: aqueous solution of sodium hydroxide = 10:4:2:2. After the feeding is completed, raise the temperature to 60 °C, keep stirring at the temperature until the end of the insulation, and then cool to room temperature by air cooling. Adjust the pH to neutral to obtain the additive solution I.

[0053] (2) Prepare a mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol. In the mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol, the concentration of acid-type sophorolipid is 14 g / L, the volume percentage of ethanol is 50%, the volume percentage of glycerol is 7%, and the solvent is water. Heat the mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol in a water bath to 70 °C and keep it warm. During the warming process, carry out condensation reflux. Then, add p-toluenesulfonic acid under stirring. After the addition is completed, continue stirring at 70 °C for 2 h. After the stirring ends, cool it naturally to room temperature, and add sodium lauroyl sarcosinate. The amounts of p-toluenesulfonic acid and sodium lauroyl sarcosinate added are in a volume ratio to the mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol as follows: p-toluenesulfonic acid:sodium lauroyl sarcosinate:mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol = 3 g:9 g:1 L. After the addition is completed, continue stirring for 30 min to obtain Additive Solution II;

[0054] (3) Add bovine serum albumin to deionized water. The amount ratio of bovine serum albumin added to deionized water is bovine serum albumin:deionized water = 2.5 g:100 mL. This is Additive Solution III for this comparative example;

[0055] (4) Mix the calcium chloride solution, Additive Solution I, Additive Solution II, and Additive Solution III evenly, and then add the ammonium carbonate solution under stirring. The volume ratio of the calcium chloride solution, Additive Solution I, Additive Solution II, Additive Solution III, and ammonium carbonate solution is calcium chloride solution:Additive Solution I:Additive Solution II:Additive Solution III:ammonium carbonate solution = 50:3:3:3:50. Among them, in the calcium chloride solution, the concentration of calcium ions is 0.4 mol / L. Among them, in the ammonium carbonate solution, the concentration of carbonate ions is 0.4 mol / L. After the addition is completed, quickly stir until no more precipitation occurs, and then carry out solid-liquid separation. Wash the solid phase 3 times with deionized water, then wash it 3 times with ethanol, and dry it at 110 °C for 2 h to obtain the calcium carbonate filler of this comparative example.

[0056] Example 5

[0057] Test the specific surface area of the calcium carbonate fillers prepared by the methods of the above examples and comparative examples. The results are shown in Table 1.

[0058] As can be seen from Table 1, the nano-calcium carbonate filler prepared by the method of the present invention has a porous structure and good dispersibility, which is manifested by a relatively high specific surface area. As a filler, it can significantly improve the performance of the composite material. By comparing Example 3 with each comparative example, it can be seen that by adding the additive solution of the present invention, the specific surface area of the filler can be significantly increased. The main reason may be as follows: First, the present invention carboxylates tannic acid, grafts carboxyl groups to some of the hydroxyl groups on the surface of tannic acid, increases the content of carboxyl groups on the surface of tannic acid, and then improves the adsorption of tannic acid on calcium carbonate. After the calcium carbonate crystal nuclei are formed, the modified tannic acid macromolecules are easily adsorbed on the surface of the crystal nuclei, inhibiting the growth of the crystal nuclei, playing a role in refining the crystal grains and increasing the specific surface area. At the same time, the growth of the surface part of the crystal nuclei is slow due to adsorption, resulting in more pores in the final crystals. Sophorolipid can significantly improve the performance of sophorolipid as a surfactant through an esterification reaction with small molecule alcohols under the action of p-toluenesulfonic acid, and is also beneficial to the refinement of crystal grains and the formation of pores. Bovine serum albumin is first oxidized and then glycosylated with glucose, which can effectively improve the dispersibility of crystal nuclei, prevent agglomeration, reduce the particle size, and increase the specific surface area.

[0059] Table 1

[0060] Experimental group <![CDATA[Specific surface area (m 2 / g)]]> Example 1 7.68 Example 2 7.73 Example 3 7.76 Example 4 7.74 Comparative example 1 6.31 Comparative example 2 6.80 Comparative example 3 6.72

[0061] The technical solution provided by the present invention has been introduced in detail above. For those of ordinary skill in the art, according to the idea of the embodiments of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A preparation method of a porous nano calcium carbonate filler, characterized in that, It includes the following steps: (1) Prepare an aqueous solution of tannic acid and an aqueous solution of 4-chlorobutyric acid; keep the aqueous solution of tannic acid at a constant temperature of 50 ± 5 °C in a water bath, stir the aqueous solution of tannic acid, add an aqueous solution of sodium acetate to the solution under stirring, continue stirring for more than 20 min after the addition is completed, then add the aqueous solution of 4-chlorobutyric acid under stirring, continue stirring at 50 ± 5 °C for more than 2 h after the addition is completed, then add an aqueous solution of sodium hydroxide, raise the temperature to 60 ± 5 °C after the addition is completed, keep stirring at a constant temperature for more than 3 h after reaching the temperature, air-cool to room temperature after the heat preservation is completed, adjust the pH to neutral to obtain additive solution I; (2) Prepare a mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol; heat the mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol to 70 ± 5 °C in a water bath for heat preservation, carry out condensation reflux during the heat preservation process, then add p-toluenesulfonic acid under stirring, continue stirring at 70 ± 5 °C for 2 - 3 h after the addition is completed, cool naturally to room temperature after the stirring is completed, add sodium lauroyl sarcosinate, continue stirring for more than 30 min after the addition is completed to obtain additive solution II; (3) Add bovine serum albumin to deionized water, stir for more than 20 min, then add hydrogen peroxide to the solution under stirring, stir for more than 20 min after the addition is completed, then place it in an environment of 4 - 5 °C and let it stand for more than 10 h, then add glucose, stir for more than 10 min after the addition, heat to 90 ± 5 °C, keep stirring at a constant temperature for more than 2 h after reaching the temperature, carry out condensation reflux during the heat preservation process, then cool naturally to room temperature to obtain additive solution III; (4) Mix the calcium salt solution, the additive solution I, additive solution II, and additive solution III evenly, then add a carbonate solution under stirring, quickly stir until no more precipitation occurs after the addition is completed, then carry out solid-liquid separation, wash the solid phase with deionized water more than 3 times, then wash it with ethanol more than 3 times, and dry it to obtain the porous nano calcium carbonate filler.

2. The preparation method of a porous nano calcium carbonate filler according to claim 1, wherein, In the step (1), in the aqueous solution of tannic acid, the concentration of tannic acid is 30 - 40 g / L, and the solvent is water; in the aqueous solution of 4-chlorobutyric acid, the concentration of 4-chlorobutyric acid is 10 - 15 g / L, and the solvent is water; in the aqueous solution of sodium acetate, the concentration of sodium acetate is 60 - 70 g / L, and the solvent is water; in the aqueous solution of sodium hydroxide, the mass percentage of sodium hydroxide is 20%, and the solvent is water; the mixing volume ratio of the aqueous solution of tannic acid, the aqueous solution of 4-chlorobutyric acid, the aqueous solution of sodium acetate, and the aqueous solution of sodium hydroxide is aqueous solution of tannic acid : aqueous solution of 4-chlorobutyric acid : aqueous solution of sodium acetate : aqueous solution of sodium hydroxide = 10 : 3 - 5 : 1 - 2 : 1 - 2.

3. The preparation method of a porous nano-calcium carbonate filler according to claim 1, characterized in that, In the step (2), in the mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol, the concentration of acid-type sophorolipid is 10 - 15 g / L, the volume percentage of ethanol is 40% - 50%, the volume percentage of glycerol is 5% - 8%, and the solvent is water; the amounts of p-toluenesulfonic acid and sodium lauroyl sarcosinate added are in a volume ratio to the mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol as p-toluenesulfonic acid:sodium lauroyl sarcosinate:mixed aqueous solution of acid-type sophorolipid, ethanol, and glycerol = 2 - 3 g:8 - 10 g:1 L.

4. The preparation method of a porous nano-calcium carbonate filler according to claim 1, characterized in that, In the step (3), the ratio of the amount of bovine serum albumin added to deionized water is bovine serum albumin:deionized water = 2 - 2.5 g:100 mL; the addition amounts of hydrogen peroxide and glucose are in a ratio to the addition amount of bovine serum albumin as hydrogen peroxide:glucose:bovine serum albumin = 0.6 - 0.8 mL:1 - 1.4 g:2 - 2.5 g; where the mass percentage of the solute in the hydrogen peroxide is 10%.

5. The preparation method of a porous nano calcium carbonate filler according to claim 1, characterized in that, In the step (4), the volume ratio of the calcium salt solution, the additive solution I, the additive solution II, the additive solution III, and the carbonate solution is calcium salt solution:additive solution I:additive solution II:additive solution III:carbonate solution = 50:2 - 3:2 - 3:2 - 3:50; where the calcium salt solution is an aqueous solution of a soluble calcium salt, and the concentration of calcium ions is 0.4 - 0.5 mol / L; where the carbonate solution is an aqueous solution of a soluble carbonate, and the concentration of carbonate ions is 0.4 - 0.5 mol / L.