Preparation method of degradable high water absorption sponge pad with bacteriostatic function

Abstract

The application belongs to the field of livestock and aquatic product preservation materials. A preparation method of a degradable high water absorption sponge pad with antibacterial function, characterized in that the method comprises the following steps: (1) preparing a nanocellulose antibacterial suspension; (2) preparing a dispersion; (3) preparing a lower water absorption sponge pad; (4) preparing a degradable high water absorption sponge pad with antibacterial function: weighing the antibacterial bacterial cellulose dispersion in step (2), adding an alkaline solution, stirring uniformly, adding the mixed dispersion into the unfrozen sponge pad in step (3), placing them in a refrigerator for freezing, then thawing at room temperature, placing them in the refrigerator again for freezing, repeating the operation for several times; then washing the sponge with deionized water until neutral, drying in air to obtain a degradable high water absorption sponge pad with antibacterial function. The sponge pad can inhibit the growth and reproduction of microorganisms during the storage and transportation of food, absorb excess water and meat juice, and prolong the shelf life of livestock and aquatic products.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of livestock and aquatic product preservation materials, and particularly relates to a preparation method of a degradable high-water-absorption sponge pad with antibacterial function. BACKGROUND

[0002] In the process of food preservation and storage, for many livestock and aquatic products, the main problem is not only microbial contamination, but also that fresh meat contains a large amount of water, and a large amount of meat juice will seep out after being stored for a period of time, which is also the main reason for reducing the sensory quality of food. In addition, the accumulation of meat juice will cause rapid reproduction of microorganisms and make the food produce odor, thereby shortening the shelf life.

[0003] At present, dust-free paper water-absorbing pads are mostly used to absorb the meat juice and blood water seeping out of the package, so as to improve the sanitary environment inside the livestock and aquatic product package. The adsorption principle of such dust-free paper water-absorbing pads is physical adsorption, and the meat juice and blood water can be transported to the inside of the material through capillary action. However, the dust-free paper water-absorbing pad has limited ability to absorb blood water and inhibit the reproduction of spoilage bacteria, and the preservation effect on food is not ideal. Therefore, it is necessary to prepare a water-absorbing pad with high water absorption and antibacterial properties.

[0004] The antibacterial sponge pad has the effect of absorbing excess water in livestock and aquatic products, inhibiting the growth of microorganisms, and prolonging the shelf life of food.

[0005] The sponge pad prepared by the application has upper antibacterial property and lower water absorption, and has both water absorption and antibacterial property with a small amount of antibacterial agent, and has great application potential in the field of food preservation. SUMMARY

[0006] The application provides a preparation method of a degradable high-water-absorption sponge pad with antibacterial function, which can inhibit the growth and reproduction of microorganisms in the process of food storage and transportation, absorb excess water and meat juice, and prolong the shelf life of livestock and aquatic products.

[0007] To achieve the above-mentioned purpose, the technical scheme adopted by the application is as follows: a preparation method of a degradable high-water-absorption sponge pad with antibacterial function, characterized by comprising the following steps:

[0008] (1) preparing a nanocellulose antibacterial suspension, using one of the following four:

[0009] a. According to the zinc acetate: nanocellulose suspension = 0.2-0.45 g: 20 mL, the zinc acetate is dissolved in the nanocellulose suspension (the concentration of the nanocellulose suspension is 0.5-2 mg / mL) to obtain a mixed solution; the mixed solution is stirred on a magnetic stirrer, NaOH solution is added to adjust the pH of the mixed solution to 10 (the concentration of the NaOH solution is 0.5-2 mg / mL), and then stirred for 20-50 min; the mixed solution is moved into a polytetrafluoroethylene reaction kettle and heated at 90-110°C for 8-12 h; a white turbid liquid is obtained, which is cooled to room temperature and then centrifuged, and the white product is collected and washed with deionized water; according to the zinc acetate: deionized water = 0.2-0.45 g: 20-40 mL, deionized water is added and ultrasonically dispersed to obtain a uniformly dispersed nanocellulose antibacterial suspension (i.e., a nanometer zinc oxide / nanocellulose antibacterial suspension);

[0010] b. According to the sodium selenite: nanocellulose suspension = 0.1-0.4 g: 20 mL, the sodium selenite is dissolved in the nanocellulose suspension (the concentration of the nanocellulose suspension is 0.5-2 mg / mL), and after mixing, it is left to stand for 10-30 min; according to the sodium selenite: water: ascorbic acid = 0.1-0.2 g: 10 mL: 0.85 g, water and ascorbic acid are added to obtain a mixed solution; the mixed solution is placed in a 35-45°C water bath for 1 h and left to stand for reaction; after the reaction is completed, centrifugation is performed, the precipitate is collected, and deionized water is added for washing; according to the sodium selenite: deionized water = 0.1-0.4 g: 20-40 mL, deionized water is added and ultrasonically dispersed to obtain a uniformly dispersed nanocellulose antibacterial suspension (i.e., a nanometer selenium / nanocellulose antibacterial suspension);

[0011] c. According to the AgNO3 solution: nanocellulose suspension = 0.4-0.6 mL: 20 mL, the AgNO3 solution (the mass concentration of the AgNO3 solution is 1-5%) is added to the nanocellulose suspension (the concentration of the nanocellulose suspension is 0.5-2 mg / mL) to obtain a mixed solution; the mixed solution is moved into a polytetrafluoroethylene reaction kettle and heated at 135-150°C for 4 h; a light yellow liquid is obtained, which is cooled to room temperature and then centrifuged, and deionized water is added for washing and centrifugation; according to the AgNO3 solution: deionized water = 0.4-0.6 mL: 20-40 mL, deionized water is added and ultrasonically dispersed to obtain a uniformly dispersed nanocellulose antibacterial suspension (i.e., a nanometer silver / nanocellulose antibacterial suspension);

[0012] d. The antibacterial agent is dispersed in the nanocellulose suspension (the concentration of the nanocellulose suspension is 0.5-2 mg / mL) to obtain a uniformly dispersed nanocellulose antibacterial suspension; the antibacterial agent is one of nanometer zinc oxide, nanometer silver, nanometer selenium, and nanometer titanium dioxide;

[0013] The nanocellulose is one of cellulose nanowhiskers, cellulose nanofibers, and bacterial cellulose.

[0014] (2) Preparation of a dispersion liquid: bacterial cellulose is dispersed in deionized water and the nanocellulose antibacterial suspension prepared in step (1) respectively to prepare a bacterial cellulose dispersion liquid (i.e., a deionized water dispersed bacterial cellulose dispersion liquid) and a bacteriostatic bacterial cellulose dispersion liquid (i.e., a bacterial cellulose dispersion liquid with bacteriostatic property);

[0015] (3) Preparation of a lower water-absorbing sponge pad: the bacterial cellulose dispersion liquid prepared in step (2) is weighed and mixed with an alkaline solution to obtain a mixed dispersion liquid; the mixed dispersion liquid is frozen in a refrigerator and then thawed at room temperature to obtain a thawed sponge pad (i.e., a lower water-absorbing sponge pad);

[0016] (4) Preparation of a degradable high water-absorbing sponge pad with bacteriostatic function: the bacteriostatic bacterial cellulose dispersion liquid prepared in step (2) is weighed and mixed with an alkaline solution to obtain a mixed dispersion liquid with bacteriostatic property; the mixed dispersion liquid is added to the thawed sponge pad in step (3) and then frozen in a refrigerator, and then thawed at room temperature and frozen again in a refrigerator, and the operation is repeated for several times (2-6 times); then the sponge pad is washed with deionized water until neutral, and dried in air to obtain a degradable high water-absorbing sponge pad with bacteriostatic function (i.e., the mixed dispersion liquid forms an upper bacteriostatic sponge pad on the lower water-absorbing sponge pad).

[0017] Preferably, the nanocellulose in step (1) is any one of cellulose nanowhiskers, cellulose nanofibers, and bacterial cellulose.

[0018] Preferably, in step (1), the antibacterial agent is 0.2 g and the nanocellulose suspension is 20 mL.

[0019] Preferably, in step (1), the concentration of the nanocellulose suspension is 0.5-2 mg / mL.

[0020] Preferably, in step (2), the mass percentage of bacterial cellulose in the bacterial cellulose dispersion (i.e., the deionized water dispersed bacterial cellulose dispersion) is 4%-6%; the mass percentage of bacterial cellulose in the bacteriostatic bacterial cellulose dispersion (i.e., the bacterial cellulose dispersion with bacteriostatic property) is 1%-3%.

[0021] Preferably, in step (3), the bacterial cellulose dispersion:alkaline solution = 4g:2mL.

[0022] Preferably, in step (3), the alkaline solution is any one of sodium hydroxide, potassium hydroxide, lithium hydroxide;

[0023] The concentration of the alkaline solution is 0.25mol / L-2mol / L.

[0024] Preferably, in step (3), the bacterial cellulose dispersion is placed in a refrigerator for freezing: the freezing condition is-10℃~-30℃, and the freezing time is 3h-12h.

[0025] Preferably, in step (4), the bacteriostatic bacterial cellulose dispersion:alkaline solution = 2g:2mL.

[0026] Preferably, in step (4), the alkaline solution is any one of sodium hydroxide, potassium hydroxide, lithium hydroxide;

[0027] The concentration of the alkaline solution is 0.25mol / L-2mol / L.

[0028] Preferably, in step (4), the bacteriostatic bacterial cellulose dispersion is placed in a refrigerator for freezing: the freezing condition is-10℃~-30℃, and the freezing time is 3h-12h.

[0029] Preferably, in step (4), the repeated operation is performed for 2-6 times.

[0030] The application provides a preparation method of a degradable high-water-absorption sponge pad with bacteriostatic function, which comprises the following steps: taking nanocellulose as a template to synthesize a nanocellulose antibacterial suspension of nanoparticles, improving the antibacterial property of the nanoparticles, taking bacterial cellulose as a skeleton and combining an antibacterial agent to prepare a sponge upper layer with bacteriostatic property, taking pure bacterial cellulose as a sponge lower layer to prepare a sponge lower layer with high water absorption, and dispersing the sponge upper layer and the sponge lower layer in an alkaline solution respectively and performing a distribution freezing and thawing process to obtain a sponge pad with bacteriostatic and water absorption properties.

[0031] Compared with the prior art, the application has the following beneficial effects: the preparation method of the degradable high water absorption sponge pad with antibacterial function provided by the application has simple process and environmentally friendly and degradable raw materials; the antibacterial agent can be dispersed in the sponge, so that the sponge has antibacterial effect in the preservation process, and the water absorption of the sponge can absorb the moisture in the packaging material and the juice exuded in the storage process, thereby prolonging the shelf life of aquatic products from two aspects. The double-layer sponge pad with antibacterial layer and water absorption layer can realize the antibacterial and water absorption functions while reducing the use of antibacterial agents, reducing the production cost, improving the biological safety of the sponge pad, and having industrialization potential in food preservation. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 An optical photo of the degradable high water absorption sponge pad with antibacterial function prepared in Example 1 of the application in a dry state.

[0033] Figure 2 A graph of the antibacterial property of the degradable high water absorption sponge pad with antibacterial function prepared in Example 1 of the application on Escherichia coli and Staphylococcus aureus in a dry state.

[0034] Figure 3 An optical photo of the degradable high water absorption sponge pad with antibacterial function prepared in Example 1 of the application in a water absorption state and a corresponding water absorption rate graph.

[0035] Figure 4 A preparation process schematic diagram of the lower water absorption sponge pad and the upper antibacterial sponge pad of the degradable high water absorption sponge pad with antibacterial function prepared in Example 1 of the application. DETAILED DESCRIPTION

[0036] The preparation method of the degradable high water absorption sponge pad with antibacterial function provided by the application is further described below in combination with examples.

[0037] Example 1

[0038] A preparation method of a degradable high water absorption sponge pad with antibacterial function, comprising the following steps:

[0039] (1) Preparation of nanocellulose antibacterial suspension: 0.45 g of zinc acetate was dissolved in 20 mL of 1 mg / mL bacterial cellulose suspension (i.e., nanocellulose suspension), to obtain a mixture; the mixture was placed on a magnetic stirrer for vigorous stirring, 1 mol / L NaOH solution was added to adjust the pH of the mixture to 10, followed by stirring for 30 min, the mixture was moved into a polytetrafluoroethylene reaction kettle and heated at 100℃ for 10 h; the white turbid liquid was cooled to room temperature and centrifuged, the white product was collected and washed with deionized water; 40 mL of deionized water was added and ultrasonically dispersed to obtain a uniformly dispersed nanocellulose antibacterial suspension (i.e., nanometer zinc oxide / nanocellulose antibacterial suspension);

[0040] (2) Preparation of dispersion liquid: bacterial cellulose was dispersed in deionized water to prepare a bacterial cellulose dispersion liquid with a mass concentration of 4%; bacterial cellulose was dispersed in the nanocellulose antibacterial suspension prepared in step (1) to prepare an antibacterial bacterial cellulose dispersion liquid with a mass concentration of 2%;

[0041] (3) Preparation of lower water-absorbing sponge pad: 4 g of the bacterial cellulose dispersion liquid described in step (2) was weighed, 2 mL of 1 mol / L NaOH solution was added, and the mixture was stirred uniformly to obtain a mixed dispersion liquid; the mixed dispersion liquid was frozen in a -18℃ refrigerator for 3 h, and then thawed at room temperature to obtain a thawed sponge pad (i.e., a lower water-absorbing sponge pad);

[0042] (4) Preparation of degradable high water-absorbing sponge pad with antibacterial function: 2 g of the antibacterial bacterial cellulose dispersion liquid described in step (2) was weighed, 2 mL of 1 mol / L NaOH solution was added, and the mixture was stirred uniformly to obtain a mixed dispersion liquid with antibacterial function; the mixed dispersion liquid was added to the thawed sponge pad in step (3), and they were placed together in a -18℃ refrigerator for 3 h, and then thawed at room temperature; the thawed sponge pad was again frozen in the refrigerator and the operation was repeated 4 times, after which the sponge pad was washed with deionized water until it was neutral, and then dried in air to obtain a degradable high water-absorbing sponge pad with antibacterial function (i.e., the mixed dispersion liquid formed an upper antibacterial sponge pad on the lower water-absorbing sponge pad, as shown in Figure 4 ).

[0043] The optical photograph of the degradable high water-absorbing sponge pad with antibacterial function prepared in Example 1 in a dry state is shown in Figure 1 ; the antibacterial properties of the degradable high water-absorbing sponge pad with antibacterial function prepared in Example 1 in a dry state against Escherichia coli and Staphylococcus aureus are shown in Figure 2 . Figure 2It is illustrated that the application has good bacteriostasis; the optical photograph of the prepared degradable high water-absorbing sponge pad with bacteriostasis function in water absorption state and the corresponding water absorption rate are as shown in Figure 3 , Figure 3 It is illustrated that the application has good water absorption.

[0044] Example 2

[0045] A preparation method of a degradable high water-absorbing sponge pad with bacteriostasis function, comprising the following steps:

[0046] (1) Preparation of nano-cellulose antibacterial suspension: 0.1 g of sodium selenite is dissolved in 20 mL of 1 mg / mL cellulose nanowhisker suspension (i.e. nano-cellulose suspension), after mixing, it is placed for 15 min, 10 mL of water and 0.85 g of ascorbic acid are added to obtain a mixed solution; the mixed solution is placed in a 40℃ water bath for 1 h and is placed for reaction; after the reaction is completed, centrifugation is performed, the precipitate is collected and washed with deionized water; 20 mL of deionized water is further added and ultrasonic is performed to uniformly disperse the precipitate (note that the precipitate is the precipitate after washing), to obtain a uniformly dispersed nano-cellulose antibacterial suspension (i.e. nano-selenium / nano-cellulose antibacterial suspension);

[0047] (2) Preparation of dispersion liquid: bacterial cellulose is dispersed in deionized water to prepare a bacterial cellulose dispersion liquid with a mass concentration of 6%; the bacterial cellulose is dispersed in the nano-cellulose antibacterial suspension prepared in step (1) to prepare an antibacterial bacterial cellulose dispersion liquid with a mass concentration of 2%;

[0048] (3) Preparation of lower water-absorbing sponge pad: 4 g of the bacterial cellulose dispersion liquid in step (2) is weighed, 2 mL of 1 mol / L NaOH solution is added, and stirring is uniformly performed to obtain a mixed dispersion liquid; the mixed dispersion liquid is placed in a-18℃ refrigerator for freezing for 3 h, and then is thawed at room temperature to obtain a thawed sponge pad (i.e. lower water-absorbing sponge pad);

[0049] (4) Preparation of degradable high water-absorbing sponge pad with bacteriostasis function: 2 g of the antibacterial bacterial cellulose dispersion liquid in step (2) is weighed, 2 mL of 1 mol / L NaOH solution is added, and stirring is uniformly performed to obtain a mixed dispersion liquid with bacteriostasis; the mixed dispersion liquid is added to the thawed sponge pad in step (3), and they are placed in a-18℃ refrigerator for freezing for 3 h, and then are thawed at room temperature; after thawing, the sponge is again placed in the refrigerator for freezing, and the operation is repeated for 6 times; thereafter, the sponge is washed with deionized water until neutral, and is dried in air to obtain a degradable high water-absorbing sponge pad with bacteriostasis function (i.e. the mixed dispersion liquid forms an upper antibacterial sponge pad on the lower water-absorbing sponge pad).

[0050] Example 3

[0051] A preparation method of a degradable high water-absorbing sponge pad with antibacterial function, comprising the following steps:

[0052] (1) Preparation of nanocellulose antibacterial suspension: 0.1 g of nanometer titanium dioxide is dispersed in 20 mL of 1 mg / mL cellulose nanofiber suspension (i.e., nanocellulose suspension) to obtain a mixed solution; ultrasonic dispersion is performed to obtain a uniformly dispersed nanocellulose antibacterial suspension;

[0053] (2) Preparation of dispersion liquid: bacterial cellulose is dispersed in deionized water to prepare a bacterial cellulose dispersion liquid with a mass concentration of 4%; the bacterial cellulose is dispersed in the nanocellulose antibacterial suspension prepared in step (1) to prepare an antibacterial bacterial cellulose dispersion liquid with a mass concentration of 1%;

[0054] (3) Preparation of lower water-absorbing sponge pad: 4 g of the bacterial cellulose dispersion liquid in step (2) is weighed, 2 mL of 1 mol / L LiOH solution is added, and stirring is performed until uniform to obtain a mixed dispersion liquid; the mixed dispersion liquid is placed in a-18℃ refrigerator for freezing for 3 h, and then thawed at room temperature to obtain a thawed sponge pad (i.e., a lower water-absorbing sponge pad);

[0055] (4) Preparation of degradable high water-absorbing sponge pad with antibacterial function: 2 g of the antibacterial bacterial cellulose dispersion liquid in step (2) is weighed, 2 mL of 1 mol / L LiOH solution is added, and stirring is performed until uniform to obtain a mixed dispersion liquid with antibacterial function; the mixed dispersion liquid with antibacterial function is added to the thawed sponge pad in step (3), and they are placed together in a-18℃ refrigerator for freezing for 3 h, and then thawed at room temperature; the thawed sponge pad is again placed in a refrigerator for freezing, and the operation is repeated 4 times; thereafter, the sponge is washed with deionized water until neutral, and dried in air to obtain a degradable high water-absorbing sponge pad with antibacterial function (i.e., the mixed dispersion liquid forms an upper antibacterial sponge pad on the lower water-absorbing sponge pad).

[0056] Example 4

[0057] A preparation method of a degradable high water-absorbing sponge pad with antibacterial function, comprising the following steps:

[0058] (1) Preparation of nanocellulose antibacterial suspension: 0.3 g of nanometer selenium is dispersed in 20 mL of 1 mg / mL nanocellulose suspension to obtain a mixed solution; ultrasonic dispersion is performed to obtain a uniformly dispersed nanocellulose antibacterial suspension;

[0059] (2) Preparation of dispersion liquid: bacterial cellulose is dispersed in deionized water to prepare a bacterial cellulose dispersion liquid with a mass concentration of 4%; the bacterial cellulose is dispersed in the nanocellulose antibacterial suspension prepared in step (1) to prepare an antibacterial bacterial cellulose dispersion liquid with a mass concentration of 2%;

[0060] (3) Preparation of the lower water-absorbing sponge pad: 6 g of the bacterial cellulose dispersion solution described in step (2) was added with 2 mL of 2 mol / L NaOH solution, and stirred uniformly to obtain a mixed dispersion solution; the mixed dispersion solution was placed in a refrigerator at -30°C for 3 h, and then thawed at room temperature to obtain a thawed sponge pad (i.e., the lower water-absorbing sponge pad);

[0061] (4) Preparation of the degradable high water-absorbing sponge pad with antibacterial function: 4.0 g of the antibacterial bacterial cellulose dispersion solution described in step (2) was added with 2 mL of 2 mol / L NaOH solution, and stirred uniformly to obtain a mixed dispersion solution with antibacterial function; the mixed dispersion solution was added to the thawed sponge pad in step (3), and placed together in a refrigerator at -30°C for 3 h, and then thawed at room temperature; the thawed sponge pad was again placed in the refrigerator for freezing, and the operation was repeated 4 times; thereafter, the sponge pad was washed with deionized water until neutral, and dried in air to obtain a degradable high water-absorbing sponge pad with antibacterial function (i.e., the mixed dispersion solution formed an upper antibacterial sponge pad on the lower water-absorbing sponge pad).

[0062] Example 5

[0063] A method for preparing a degradable high water-absorbing sponge pad with antibacterial function, comprising the following steps:

[0064] (1) Preparation of a nanocellulose antibacterial suspension: 0.2 g of nanosilver was dispersed in 20 mL of 1 mg / mL nanocellulose suspension to obtain a mixed solution; the mixed solution was uniformly dispersed by ultrasonic treatment to obtain a uniformly dispersed nanocellulose antibacterial suspension;

[0065] (2) Preparation of a dispersion solution: bacterial cellulose was dispersed in deionized water to prepare a bacterial cellulose dispersion solution with a mass concentration of 5%; the bacterial cellulose was dispersed in the nanocellulose antibacterial suspension prepared in step (1) to prepare an antibacterial bacterial cellulose dispersion solution with a mass concentration of 2%;

[0066] (3) Preparation of the lower water-absorbing sponge pad: 5 g of the bacterial cellulose dispersion solution described in step (2) was added with 2 mL of 0.25 mol / L NaOH solution, and stirred uniformly to obtain a mixed dispersion solution; the mixed dispersion solution was placed in a refrigerator at -10°C for 12 h, and then thawed at room temperature to obtain a thawed sponge pad (i.e., the lower water-absorbing sponge pad);

[0067] (4) Preparation of the degradable high water-absorbing sponge pad with antibacterial function: 3 g of the antibacterial bacterial cellulose dispersion solution described in step (2) is taken, 2 mL of 0.25 mol / L NaOH solution is added, and the mixture is stirred uniformly. The mixed dispersion solution is added to the sponge pad after thawing in step (3), and is placed in a-10°C refrigerator for freezing for 12 h. Then, it is thawed at room temperature, and is placed in the refrigerator again for freezing. The operation is repeated twice. After that, the sponge is washed with deionized water until it is neutral. After drying in air, the degradable high water-absorbing sponge pad with antibacterial function is obtained (i.e., the mixed dispersion solution forms an upper antibacterial sponge pad on the lower water-absorbing sponge pad).

[0068] Example 6

[0069] A method for preparing a degradable high water-absorbing sponge pad with antibacterial function, comprising the following steps:

[0070] (1) Preparation of a nanocellulose antibacterial suspension: 0.5 mL of a 1% AgNO3 solution by mass concentration is added to 20 mL of a 1 mg / mL nanocellulose suspension to obtain a mixed solution. The mixed solution is transferred into a polytetrafluoroethylene reaction kettle and heated at 140°C for 4 h. A light yellow liquid is obtained. After cooling to room temperature, centrifugation is performed, and deionized water is added for washing and centrifugation. Then, 30 mL of deionized water is added for ultrasonic dispersion (note that “it” refers to the precipitate after washing and centrifugation) to obtain a uniformly dispersed nanocellulose antibacterial suspension (i.e., a nanosilver / nanocellulose antibacterial suspension);

[0071] (2) Preparation of a dispersion solution: bacterial cellulose is dispersed in deionized water to prepare a bacterial cellulose dispersion solution with a mass concentration of 4%; and the bacterial cellulose is dispersed in the nanocellulose antibacterial suspension prepared in step (1) to prepare an antibacterial bacterial cellulose dispersion solution with a mass concentration of 2%;

[0072] (3) Preparation of a lower water-absorbing sponge pad: 6 g of the bacterial cellulose dispersion solution described in step (2) is taken, 2 mL of a 2.0 mol / L NaOH solution is added, and the mixture is stirred uniformly to obtain a mixed dispersion solution. The mixed dispersion solution is placed in a-10°C refrigerator for freezing for 3 h, and then is thawed at room temperature to obtain a thawed sponge pad (i.e., a lower water-absorbing sponge pad);

[0073] (4) Preparation of the degradable high water-absorption sponge pad with antibacterial function: 3 g of the antibacterial bacterial cellulose dispersion solution described in step (2) was weighed, 2 mL of 0.25 mol / L NaOH solution was added, and the mixture was stirred uniformly. The mixed dispersion solution was added to the sponge pad after thawing in step (3), and was placed in a-10°C refrigerator for freezing for 3 h. Then, it was thawed at room temperature, and was placed in the refrigerator again for freezing. The operation was repeated twice. Then, the sponge was washed with deionized water until it was neutral. After drying in air, the degradable high water-absorption sponge pad with antibacterial function was obtained (i.e., the mixed dispersion solution formed an upper layer of antibacterial sponge pad on the lower layer of water-absorption sponge pad).

[0074] Example 7

[0075] A method for preparing a degradable high water-absorption sponge pad with antibacterial function, comprising the following steps:

[0076] (1) Preparation of the nanocellulose antibacterial suspension: 0.2 g of nanometer zinc oxide was dispersed in 20 mL of 1 mg / mL nanocellulose suspension to obtain a mixed solution; and the mixed solution was ultrasonically dispersed to obtain a uniformly dispersed nanocellulose antibacterial suspension;

[0077] (2) Preparation of the dispersion solution: bacterial cellulose was dispersed in deionized water to prepare a bacterial cellulose dispersion solution with a mass concentration of 5%; and the bacterial cellulose was dispersed in the nanocellulose antibacterial suspension prepared in step (1) to prepare an antibacterial bacterial cellulose dispersion solution with a mass concentration of 2%;

[0078] (3) Preparation of the lower layer of water-absorption sponge pad: 5 g of the bacterial cellulose dispersion solution described in step (2) was weighed, 2 mL of 0.25 mol / L NaOH solution was added, and the mixture was stirred uniformly to obtain a mixed dispersion solution; the mixed dispersion solution was placed in a-10°C refrigerator for freezing for 12 h, and then was thawed at room temperature to obtain a thawed sponge pad (i.e., the lower layer of water-absorption sponge pad);

[0079] (4) Preparation of the degradable high water-absorption sponge pad with antibacterial function: 3 g of the antibacterial bacterial cellulose dispersion solution described in step (2) was weighed, 2 mL of 0.25 mol / L NaOH solution was added, and the mixture was stirred uniformly. The mixed dispersion solution was added to the sponge pad after thawing in step (3), and was placed in a-10°C refrigerator for freezing for 12 h. Then, it was thawed at room temperature, and was placed in the refrigerator again for freezing. The operation was repeated twice. Then, the sponge was washed with deionized water until it was neutral. After drying in air, the degradable high water-absorption sponge pad with antibacterial function was obtained (i.e., the mixed dispersion solution formed an upper layer of antibacterial sponge pad on the lower layer of water-absorption sponge pad).

[0080] The above merely describes the preferred embodiments of the present application, and it should be pointed out that, for those skilled in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as falling within the protection scope of the present application.

Claims

1. A method for preparing a biodegradable superabsorbent sponge pad with antibacterial function, characterized in that... Includes the following steps: (1) Prepare the nanocellulose antibacterial suspension by one of the following four methods: a. Dissolve zinc acetate in nanocellulose suspension at a ratio of 0.2-0.45 g: 20 mL to obtain a mixture. Stir the mixture on a magnetic stirrer, add NaOH solution to adjust the pH of the mixture to 10, stir for 20-50 min, transfer the mixture to a polytetrafluoroethylene reactor, and heat at 90-110 ℃ for 8-12 h. After cooling the white turbid liquid to room temperature, centrifuge to collect the white product, and wash with deionized water. Add deionized water according to the ratio of zinc acetate:deionized water = 0.2-0.45 g: 20-40 mL, and sonicate to disperse it evenly to obtain a uniformly dispersed nanocellulose antibacterial suspension. b. Dissolve sodium selenite in nanocellulose suspension at a ratio of 0.1-0.4 g: 20 mL, mix well, and let stand for 10-30 min. Add water and ascorbic acid at a ratio of 0.1-0.2 g: 10 mL: 0.85 g to obtain a mixture. Place the mixture in a 35-45 ℃ water bath for 1 h and let it stand to react. After the reaction is complete, centrifuge, collect the precipitate, and wash with deionized water. Add deionized water at a ratio of 0.1-0.4 g: 20-40 mL and sonicate to disperse it evenly to obtain a uniformly dispersed nanocellulose antibacterial suspension. c. Add AgNO3 solution to the nanocellulose suspension at a ratio of 0.4-0.6 mL: 20 mL to obtain a mixture. Transfer the mixture to a polytetrafluoroethylene reactor and heat at 135-150 °C for 4 h. After cooling the resulting pale yellow liquid to room temperature, centrifuge and wash with deionized water. Add deionized water at a ratio of 0.4-0.6 mL: 20-40 mL and sonicate to disperse the mixture evenly, resulting in a uniformly dispersed antibacterial nanocellulose suspension. d. Disperse the antibacterial agent in the nanocellulose suspension at a ratio of 0.1-0.4 g to 20 mL, and sonicate to ensure uniform dispersion, thereby obtaining a uniformly dispersed nanocellulose antibacterial suspension; the antibacterial agent is one of nano zinc oxide, nano silver, nano selenium, or nano titanium dioxide. (2) Preparation of dispersion: Bacterial cellulose is dispersed in deionized water and the antibacterial nanocellulose suspension prepared in step (1) to prepare bacterial cellulose dispersion and antibacterial bacterial cellulose dispersion, respectively. (3) Preparation of the lower absorbent sponge pad: Weigh the bacterial cellulose dispersion described in step (2) according to the ratio of bacterial cellulose dispersion to alkaline solution = 4.0-6.0 g: 2 mL, add alkaline solution, stir evenly to obtain a mixed dispersion; put the mixed dispersion into the refrigerator to freeze, and then thaw at room temperature to obtain the thawed sponge pad; (4) Preparation of biodegradable superabsorbent sponge pad with antibacterial function: Weigh the antibacterial bacterial cellulose dispersion described in step (2) according to the ratio of antibacterial bacterial cellulose dispersion to alkaline solution = 2.0-4.0 g: 2 mL, add alkaline solution, stir evenly to obtain a mixed dispersion with antibacterial properties; add the mixed dispersion to the sponge pad after thawing in step (3), put them together in the refrigerator to freeze, then thaw at room temperature, and put them back in the refrigerator to freeze again, repeating the operation several times; then wash the sponge with deionized water until neutral, and dry it in the air to obtain a biodegradable superabsorbent sponge pad with antibacterial function.

2. The method for preparing a biodegradable superabsorbent sponge pad with antibacterial function according to claim 1, characterized in that: In step (1), the concentration of the nanocellulose suspension is 0.5-2 mg / mL; the nanocellulose is one of cellulose nanocrystals, cellulose nanofibers, and bacterial cellulose.

3. The method for preparing a biodegradable superabsorbent sponge pad with antibacterial function according to claim 1, characterized in that: In step (2), the bacterial cellulose dispersion contains 4%-6% by mass; the antibacterial bacterial cellulose dispersion contains 1%-3% by mass.

4. The method for preparing a biodegradable superabsorbent sponge pad with antibacterial function according to claim 1, characterized in that: In step (3), the bacterial cellulose dispersion : alkaline solution = 4 g : 2 mL.

5. The method for preparing a biodegradable superabsorbent sponge pad with antibacterial function according to claim 1, characterized in that: In step (3), the alkaline solution is any one of sodium hydroxide solution, potassium hydroxide solution, and lithium hydroxide solution; the concentration of the alkaline solution is 0.25 mol / L-2 mol / L.

6. The method for preparing a biodegradable superabsorbent sponge pad with antibacterial function according to claim 1, characterized in that: In step (3), the food is placed in a refrigerator to freeze: the freezing conditions are -30 ℃ to -10 ℃, and the freezing time is 3 h to 12 h.

7. The method for preparing a biodegradable superabsorbent sponge pad with antibacterial function according to claim 1, characterized in that: In step (4), the ratio of antibacterial bacterial cellulose dispersion to alkaline solution is 2 g to 2 mL.

8. The method for preparing a biodegradable superabsorbent sponge pad with antibacterial function according to claim 1, characterized in that: In step (4), the alkaline solution is any one of sodium hydroxide solution, potassium hydroxide solution, and lithium hydroxide solution; the concentration of the alkaline solution is 0.25 mol / L-2 mol / L.

9. The method for preparing a biodegradable superabsorbent sponge pad with antibacterial function according to claim 1, characterized in that: In step (4), the food is placed in a refrigerator to freeze: the freezing conditions are -30 ℃ to -10 ℃, and the freezing time is 3 h to 12 h.

10. The method for preparing a biodegradable superabsorbent sponge pad with antibacterial function according to claim 1, characterized in that: In step (4), the repeated operation is performed 2-6 times.

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