CN113332172B - Preparation method of nanofiber gel membrane based on bagasse pith quaternary ammonium salt polysaccharide - Google Patents

Abstract

The invention discloses a preparation method of a nanofiber gel membrane based on bagasse quaternary ammonium salt polysaccharide, which is characterized in that air-dried bagasse raw materials are screened to obtain bagasse pulp, the bagasse pulp is delignified by adopting an acidic sodium chlorite/amino carboxylic acid complex to obtain bagasse pulp polysaccharide, and then the bagasse pulp polysaccharide is subjected to mechanical dissociation to obtain bagasse pulp polysaccharide nanofiber slurry; adopting trimethyl [3- (triethoxysilyl) propyl ] ammonium chloride and N, N-dimethylacetamide to carry out cationic modification on the bagasse pith polysaccharide nanofiber, and carrying out dialysis cleaning and decompression drying treatment after the reaction is finished to obtain the cationic polysaccharide nanofiber; the method comprises the steps of taking tartaric acid as a cross-linking agent, taking hydrochloric acid as a catalyst to carry out cross-linking reaction on cationic polysaccharide nanofibers, and then carrying out vacuum bubble removal, drying, glycerin bath washing, drying and hot pressing to form a film, thus obtaining nanofiber gel films based on bagasse pulp quaternary ammonium salt polysaccharide; the product of the invention is white film-shaped, soft in texture, good in water retention and good in inhibition effect on gram-negative bacteria and gram-positive bacteria.

Description

Preparation method of nanofiber gel film based on quaternary ammonium salt polysaccharide of sucrose pith

technical field

The invention relates to a process for preparing a nanofiber gel sticking film with high water retention and strong antibacterial properties by utilizing the agricultural solid waste---cane pith polysaccharide fiber, and belongs to the technical field of natural polymer modified materials.

Background technique

With the continuous improvement of contemporary consumption levels and the continuous infiltration and development of scientific research and technology in the daily chemical industry, the functionality of skin care products has become the focus of today's era. Moisturizing ability is the most basic function that skin care products should have. The lack of water in the skin will lead to rough skin, dull complexion, easy to produce melanin and darken the skin, and damage the brightness and elasticity of the skin to varying degrees. As a result, the metabolism of the skin is reduced and skin aging is accelerated, so moisturizing is a prerequisite for keeping the skin in good condition. The sheet mask is based on the base material of the mask (synthetic or natural sheet-like fiber) as a carrier. By adding or loading functional essence, apply it on the face and let it stand for 5-15 minutes. It can perform functions such as moisturizing, cleaning, and whitening. Mask products.

Sheet masks are one of the most convenient and widely used masks in use today. The sheet mask contains a large amount of essence, which is evenly distributed on the mask paper and has a large specific surface area, so that it can easily enter the stratum corneum of the skin and make the skin easier to absorb. Common sheet masks include non-woven masks, silk masks, cotton masks, and pulp masks, and the mask paper needs a certain thickness to stably lock the essence and relative nutrients. Usually, the sheet mask is in a wet state for a long time, and it is easy to become a petri dish for bacteria and other microorganisms. Therefore, a certain amount of preservatives need to be added when making mask paper and adding essence to facilitate the storage of the mask, such as non-woven masks. The manufacturing workshop environment is poor, and a large amount of preservatives usually need to be added. Although the silk masks on the market have good antibacterial and antibacterial capabilities, due to their high cost, most of them are not mask papers made of real silk. Therefore, plant-based polysaccharide polymers (including cellulose and hemicellulose) are currently the most popular mask substrates.

Cellulose is a natural polymer compound widely existing in nature, and it is an inexhaustible renewable energy source. As a green natural polymer material, cellulose is a polymer linear compound formed by D-glucopyranose rings connected by β-1,4 glycosidic bonds. It is basically harmless to the human body, so cellulose is used as An excellent choice for mask paper substrates. However, intramolecular and intermolecular hydrogen bonds are usually formed between the active hydroxyl groups in the long chain of cellulose, which makes the ribbon-shaped, rigid molecular chains easy to gather together to form a regular crystal structure, resulting in the passivation of hydroxyl groups and the fiber It is difficult for prime macromolecules to undergo ideal chemical and physical modification. Furthermore, due to the poor antibacterial property and poor water retention performance of natural cellulose, the application in daily chemical sticking materials is greatly limited. In order to overcome the above shortcomings, the nano-processing and functional properties of cellulose play an important role. Cellulose nanofibers exhibit remarkably high specific surface area and mechanical strength, and possess abundant reactive hydroxyl groups for further functionalization. In recent years, quaternary ammonium compounds (QACs) have been widely used in biomedical fields, water purification systems, and food packaging materials due to their high-efficiency and broad-spectrum antimicrobial properties. And QAC has a long service life and strong safety performance, so it will not release any secondary harmful substances. Therefore, the introduction of QAC with good biocompatibility into the cellulose molecular chain through etherification is an effective way to endow the film substrate with antibacterial properties.

At the same time, the hemicellulose in the polysaccharide macromolecule is a heterogeneous polysaccharide composed of different polysaccharide groups, and its molecular weight contains a large number of reactive hydroxyl groups, which can be modified by esterification, etherification, graft copolymerization, etc., thereby preparing Hemicellulose-based functional materials. Among them, the application research of hemicellulose-based water-retaining gels in many fields is not uncommon. Using acrylic acid and acrylamide as monomers and N,N-methylenebisacrylamide as a crosslinking agent, the hemicellulose extracted and purified from eucalyptus papermaking waste liquid was modified by graft copolymerization to prepare hemicellulose base Smart hydrogel, which has good water absorption and water retention, and has the functional characteristics of dual sensitivity to pH and temperature, provides a new way for the high value-added utilization of pulping waste liquid. Acrylic acid and hemicellulose isolated from viscose waste liquid were grafted and copolymerized to obtain a tough and multi-responsive hydrogel with a maximum compressive strength of 105.1-12.9 kPa. It is about 3 times that of plain-based hydrogel; the excellent mechanical properties and multi-response properties have great potential applications in the field of biomedicine and wastewater treatment. In summary, as an environmentally friendly sticking material, it is feasible to develop a fully biodegradable polysaccharide polymer-based antibacterial and water-retaining gel film, and it has very important economic and social benefits.

The three major sources of cellulose in nature are coniferous wood, broad-leaved wood and gramineous plants, and gramineous raw materials are widely distributed in China and even the world, and have a strong ability to adapt to the ecological environment. Compared with coniferous wood and broad-leaved wood, the growth cycle is shorter , is a cheap, resource available and renewable biomass. Among them, sugarcane pith is the solid residue composed of a small amount of short fibrous cells and the main parenchyma cells after sugarcane extracts its sugar, which accounts for 20% to 40% of the bagasse content, and cellulose, hemicellulose and lignin are the main components. chemical composition. China is one of the countries that produce the largest amount of sugarcane in the world, among which Yunnan is the second main sugarcane production base in my country, with an annual sucrose output of up to 1.9 million tons. Because the fiber cells are short and the parenchyma cells have no interweaving ability, the use of cane pith in the pulp and paper industry is limited. Therefore, the amount of sugarcane pith remaining after sugar cane, pulp and paper making and other processes is huge. The utilization of sugarcane pith is mainly compressed and solidified to make solid fuel, but due to its low calorific value, high ash content, low heat utilization rate in the combustion process and large pollution to the environment, it has always been in a state of low added value. The carbohydrate content of sugarcane pith is high (39.8% cellulose and 32.2% hemicellulose). From the analysis of supramolecular structure, the microfibers in the cell wall of sugarcane pith are arranged irregularly and have low crystallinity, so they are distributed in a disordered state. , and the parenchyma cells are soft and plastic, with a large specific surface area.

In summary, combined with the development of the modern daily chemical industry and the consumption of consumers, this application describes in detail the process of preparing a cationic modified polysaccharide nanofiber gel film with high water retention and strong antibacterial properties using sugarcane pith as raw material. This study not only improves the comprehensive utilization efficiency of sugarcane resources, but also makes up for the vacancy in the study of parenchyma cell polysaccharide polymers, which has played a continuous role in promoting the efficient utilization of sugarcane resources.

Contents of the invention

For the sheet mask of daily chemical products, there is not enough foundation and technical support for the effective utilization of sugarcane pith resources. Due to the need for a certain storage time, the traditional sheet mask will add a large amount of preservatives, which will cause certain damage to human skin, and the absorption capacity of the essence in the mask paper is not strong, resulting in waste in the packaging bag. Therefore, the present invention provides a method for preparing a nanofiber gel film based on sugarcane pith quaternary ammonium salt polysaccharide. The method utilizes bagasse, which is rich in resources and still underdeveloped, as a raw material, and the delignified sugarcane pith obtained by sieving is Afterwards, it is mechanically ground to prepare polysaccharide nanofibers, and the nanocellulose is subjected to quaternary ammonium salt etherification and crosslinking reactions to prepare cationic polysaccharide nanofiber gel film products, which further develops the application field of bagasse, making this environmentally friendly and renewable Green biomaterials are efficiently utilized.

Realize the object of the present invention and technical scheme is as follows:

(1) The bagasse is air-dried and sieved to obtain the raw material of cane pith, which is bagged and sealed for later use;

(2) Use acidic sodium chlorite/amino carboxylic acid complex to delignify the raw material of cane pith, wash it with deionized water until it is neutral, obtain the polysaccharide of cane pith, and store it in cold storage;

(3) The polysaccharide nanofiber (PNF) slurry is obtained by mechanical dissociation of sugarcane pith polysaccharide, which is sealed and stored after freeze-drying;

(4) Use trimethyl[3-(triethoxysilyl)propyl]ammonium chloride (TTPAC) and N, N-dimethylacetamide (DMAC) mixed solution to cationic modify PNF, react After the end, the cationic polysaccharide nanofiber (CPNF) was obtained after dialysis cleaning and drying under reduced pressure;

(5) Using tartaric acid as a cross-linking agent and hydrochloric acid as a catalyst, carry out a cross-linking reaction on CPNF, followed by vacuum degassing, drying, washing in a glycerin bath, drying and drying, and hot-pressing to form a film to obtain nano-sized quaternary ammonium salt polysaccharides Fiber gel membrane.

The specific operation of the above method is as follows:

(1) Preparation of sugarcane pith raw materials: bagasse is air-dried and sieved through a 50-100-mesh sieve to obtain sugarcane pith, which is packed into bags and sealed for later use. The rate is controlled within the range of 5~20%;

(2) Delignification treatment with acidic sodium chlorite/2-aminocyclohexylcarboxylic acid complex: add 400~800mL deionized water, 7.5g~15g sodium chlorite, 5~ 10mL of glacial acetic acid and 1.5mg~10mg of 2-aminocyclohexylcarboxylic acid, mix well and place in a constant temperature water bath at 80~85℃ for 0.5~1.5h, then add 5~10g of sodium chlorite and 3~7mL of React with glacial acetic acid for 0.5~1.5h and repeat this operation 3~5 times. After the reaction is completed, cool at room temperature, transfer the reactant to a 1500~2500 mesh nylon mesh bag and soak and wash it with deionized water until the pH of the material is neutral. After removing the water, the cane pith polysaccharide is prepared, sealed and refrigerated;

(3) Preparation of cane pith polysaccharide nanofibers: Dilute the cane pith polysaccharide with water and treat it by mechanical dissociation for 4-8 hours to obtain a 2-6% dryness pulp of cane pith polysaccharide nanofibers, freeze-dry, Sealed storage;

The mechanical dissociation is the mechanical action of a grinder, that is, the pulp fiber is rubbed by mechanical force; the dryness is the mass ratio of absolute dry matter to the pulp;

(4) Dissolve 3~60mg of trimethyl[3-(triethoxysilyl)propyl]ammonium chloride (TTPAC) in 50~500mL of N,N-dimethylacetamide in an ice-water bath (DMAC), then add 50~100mg of sucrose polysaccharide nanofiber slurry, put it at 30~60℃, stir for 24~48h under nitrogen environment, and put the reaction solution in a dialysis bag (molecular weight cut off: 2~5kDa) for use Dialyze with deionized water for 3-7 days and change the water repeatedly. The liquid in the dialysis bag is evaporated to dryness under reduced pressure, and placed in an oven at 30-60°C for 8-12 hours to obtain cationic polysaccharide nanofibers (CPNF);

(5) Realization of nanofiber gel film of quaternary ammonium salt polysaccharide of cane pith: Mix 50~100mg of cationic polysaccharide nanofibers, 100~500mg of tartaric acid, 0.01~0.1mL of hydrochloric acid in 50~300mL of water, and then place in After reacting in an oil bath at 75~115°C for 1~5h, fully remove the air bubbles in a vacuum drying oven, pour it into a polytetrafluoroethylene plate and dry it at 50~60°C for 10~13h, and put the dried cellulose film together with the polytetrafluoroethylene The vinyl plate is soaked and washed in a glycerin bath with a mass concentration of 3-5% for 24-72 hours, and the glycerin is changed 3-5 times a day. The cleaned film and the mold are dried at 40-60°C for 3-7 hours, and the film is taken out and placed in a vulcanizer. Use 60-100 ℃, 200-300kg of pressure and hot-press for 5-7h to obtain the nanofiber gel film of sugarcane pith quaternary ammonium salt polysaccharide; the product of the present invention is in the form of white film and soft in texture;

The beneficial effect of the present invention is: using the agricultural solid waste—cane pith as the source of polysaccharide macromolecule, the polysaccharide obtained by sieving the bagasse remaining in the sugar and paper industry step by step, drying and delignification The product, nano-scale fibers are prepared by mechanical refining method, which aims to open the hydrogen bonds between cellulose macromolecules. Therefore, part of the cellulose crystallization area is better destroyed, thereby exposing more active hydroxyl groups, increasing the specific surface area of polysaccharide cane pith, and increasing the reaction accessibility of cellulose. By adding DMAC to swell the cellulose, the hydrogen bond between the cellulose is further opened, which is beneficial to the quaternary ammonium salt cation endowment and tartaric acid cross-linking modification, so that the film has good antibacterial properties, water retention and shape maintenance.

Since most of the general sheet masks need to put preservatives, in order to increase the stability of the product, the patch film proposed in this patent has the effect of inhibiting the growth of bacteria (including acne bacilli) and fungi, without adding preservatives, reducing The cost of the product is reduced, the mildness and safety of the product are increased, and the patch mask itself has an anti-inflammatory effect. Therefore, the above features can greatly expand the applicable population of this product. The main components in the gel film prepared by this method are natural components such as PNF and tartaric acid. Therefore, the sticking film belongs to the green environmental protection multifunctional product.

Detailed ways

The present invention will be described in further detail below in conjunction with the examples, but the protection scope of the present invention is not limited to the content described.

Embodiment 1: The preparation method of the nanofiber gel film based on the quaternary ammonium salt polysaccharide of cane pith is as follows:

(1) Preparation of sugarcane pith

Pass the air-dried bagasse with a water content of 5% through a 50-mesh sieve but no more than 100-mesh sieve to obtain the raw material of sugarcane pith, bag and seal it, and set aside;

(2) Cane pith delignification

Put 10g of cane pith into an Erlenmeyer flask, add 400mL of deionized water, 7.5g of sodium chlorite, 5mL of glacial acetic acid and 1.5mg of 2-aminocyclohexylcarboxylic acid, mix well and place in a constant temperature water bath at 80°C After 0.5h of treatment, add 5g of sodium chlorite and 3mL of glacial acetic acid to react for 0.5h and repeat this operation 3 times. After the reaction, take out the Erlenmeyer flask to cool at room temperature, and transfer the reactant to a 1500-mesh nylon mesh bag Rinse with deionized water, soak and wash until the pH of the material is neutral, and seal and refrigerate after removing moisture;

(3) Preparation of sugarcane pith polysaccharide nanofibers

Dilute 3g of dry cane pith polysaccharide (if the dryness of cane pith polysaccharide is 20%, the actual weighed amount of dry 3g polysaccharide is 3/20%=15g) is diluted with 138mL of water and mechanically dissociated in a grinder for 4h. Get 2% dryness pulp of sucrose polysaccharide nanofibers (the amount of water added is calculated as (3/2%)-(15-3)=138g, and the water density is 1g/cm ³ , so 138mL), freeze-dried and sealed for storage ;

(4) Cationic modification of sugarcane pith polysaccharide nanofibers

Dissolve 3mg of trimethyl[3-(triethoxysilyl)propyl]ammonium chloride in 50mL of N,N-dimethylacetamide in an ice-water bath, and put 50mg of sucrose into the system Put the polysaccharide nanofiber slurry at 30°C under a nitrogen atmosphere and stir for 40 hours. After the reaction, place the reaction solution in a dialysis bag (molecular weight cut-off of 2kDa) and dialyze with deionized water for 3 days and change the water repeatedly. The liquid was evaporated to dryness under reduced pressure, and placed in an oven at 30°C for 12 hours to obtain cationic polysaccharide nanofibers;

(5) Realization of nanofibrous gel membrane of sugarcane pith quaternary ammonium salt polysaccharide

Mix 50mg of cationic polysaccharide nanofibers, 100mg of tartaric acid, and 0.01mL of hydrochloric acid in 50mL of water, and then place them in an oil bath at 75°C for 5 hours. Put it into a polytetrafluoroethylene plate and dry it in an oven at 50°C for 13 hours. The dried cellulose film and the polytetrafluoroethylene plate were soaked and washed in a glycerin bath with a mass concentration of 3% for 24 hours. The glycerin bath was changed 3 times a day. The final film and the mold were dried in an oven at 40°C for 7 hours, and the film was taken out and pressed in a vulcanizer with a pressure of 60°C and 200kg for 7 hours to obtain a nanofiber gel film of quaternary ammonium salt polysaccharide;

(6) Properties of the finished nanofiber gel film of sugarcane pith quaternary ammonium polysaccharide

Determination of the physical strength of the film: according to the ASTM D638 test method, the tensile strength and elongation at break are 1.3MPa and 20% respectively;

Determination method of water retention performance of film: measure and take several 50mg dry gel films respectively immersed in 100mL deionized water, let stand at 25°C water temperature for 72h, after adsorption balance, take out the film, wipe off the surface liquid of the film, use electronic balance The weight of the film before and after water absorption was measured, and the maximum swelling degree was calculated to be 126 g/g.

The antibacterial performance test method of the film: the film method refers to the standard QB2591, the inhibition rate of the gel film to Escherichia coli is 99.90%, and the inhibition rate to Staphylococcus aureus is 97.50%.

Embodiment 2: The preparation method of the nanofiber gel film based on sucrose pith quaternary ammonium salt polysaccharide is as follows:

(1) Preparation of sugarcane pith

Pass the air-dried bagasse with a water content of 12.5% through a 50-mesh sieve but no more than 100-mesh sieve to obtain the raw material of sugarcane pith, bag and seal it, and set aside;

(2) Cane pith delignification

Put 15g of cane pith into the Erlenmeyer flask, add 600mL of deionized water, 11.25g of sodium chlorite, 7.5mL of glacial acetic acid and 5.75mg of 2-aminocyclohexylcarboxylic acid, mix well and put it in a constant temperature of 82.5℃ After being treated in a water bath for 1 hour, add 7.5 g of sodium chlorite and 5 mL of glacial acetic acid to react for 1 hour and repeat the above operation 4 times. After the reaction, take out the Erlenmeyer flask to cool at room temperature, and transfer the reactant to a 2000-mesh nylon mesh bag for continuous Rinse with deionized water, soak and wash until the pH of the material is neutral, remove excess water and store in sealed and refrigerated storage;

(3) Preparation of sugarcane pith polysaccharide nanofibers

Using high-speed mechanical dissociation method: Dilute 6g of dry cane pith polysaccharide (if the dryness of cane pith polysaccharide is 20%, the actual weighing amount of 6g of dry polysaccharide is 6/20%=30g) add 126mL of water to dilute and use Grinder mechanical dissociation treatment for 6 hours to prepare sucrose pith polysaccharide nanofiber slurry with 4% dryness (the amount of water added is calculated as (6/4%)-(30-6)=126g, and the water density is 1g/cm ³ , so 126mL), sealed and refrigerated;

(4) Cationic modification of sugarcane pith polysaccharide nanofibers

Dissolve 31.5 mg of trimethyl[3-(triethoxysilyl)propyl]ammonium chloride in 275 mL of N,N-dimethylacetamide in an ice-water bath, and put 75 mg of sucrose into the system The polysaccharide nanofiber slurry was placed in a nitrogen environment at 45°C and stirred for 36 hours. After the reaction, the reaction solution was placed in a dialysis bag (molecular weight cut-off of 3.5kDa) and dialyzed with deionized water for 5 days, and the water was changed repeatedly. The liquid in the bag was evaporated to dryness under reduced pressure, and placed in an oven at 45°C for 10 hours to obtain cationic polysaccharide nanofibers;

(5) Realization of nanofibrous gel film of quaternary ammonium salt polysaccharide in sugarcane pith

Mix 75mg of cationic polysaccharide nanofibers, 300mg of tartaric acid, and 0.055mL of hydrochloric acid in 175mL of water, and then place them in an oil bath at 100°C for 3 hours. Put it into a polytetrafluoroethylene plate and dry it in an oven at 55 °C for 12 hours. The dried cellulose film and the polytetrafluoroethylene plate were soaked and washed in a glycerin bath with a mass concentration of 4% for 48 hours. The glycerin bath was changed 4 times a day. The final film and the mold were dried in an oven at 50°C for 5 hours, and the film was taken out and pressed in a vulcanizer with a pressure of 80°C and 250kg for 6 hours to obtain a nanofiber gel film of sucrose pith quaternary ammonium salt polysaccharide;

(6) Properties of the finished product of sugarcane pulp quaternary ammonium salt polysaccharide nanofiber gel film

Determination of the physical strength of the film: according to the ASTM D638 test method, the tensile strength and elongation at break are 2.8MPa and 32% respectively;

Determination method of water retention performance of film: measure and take several 50mg dry gel films respectively immersed in 100mL deionized water, let stand at 25°C water temperature for 72h, after adsorption balance, take out the film, wipe off the surface liquid of the film, use electronic balance Measure the weight of the film before and after water absorption, and calculate the maximum swelling degree to be 207g/g;

The antibacterial property test method of the film: the film method refers to the standard QB2591, the inhibition rate of the gel film to Escherichia coli is 99.99%, and the inhibition rate to Staphylococcus aureus is 99.00%.

Embodiment 3: The preparation method of the quaternary ammonium salt nanofiber gel film based on sucrose pith polysaccharide is as follows:

(1) Preparation of sugarcane pith

Pass the air-dried bagasse with a water content of 20% through a 50-mesh sieve but no more than 100-mesh sieve to obtain the raw material of sugarcane pith, bag and seal it, and set aside;

(2) Cane pith delignification

Put 20g of cane pith into an Erlenmeyer flask, add 800mL of deionized water, 15g of sodium chlorite, 10mL of glacial acetic acid and 10mg of 2-aminocyclohexylcarboxylic acid, mix well and put it in a constant temperature water bath at 85°C for 0.5 After one hour, add 10g of sodium chlorite and 7mL of glacial acetic acid to react for 1.5h and repeat the above operation 5 times. After the reaction, take out the Erlenmeyer flask to cool at room temperature, and transfer it to a 2500-mesh nylon mesh bag with deionized water. Rinse, soak and wash until the pH of the material is neutral, remove excess water and store in sealed and refrigerated storage;

(3) Preparation of sugarcane pith polysaccharide nanofibers

Using high-speed mechanical dissociation method: Dilute 9g of dry cane pith polysaccharide (if the dryness of cane pith polysaccharide is 20%, the actual weighed amount of 9g of dry polysaccharide is 9/20%=45g) add 114mL of water to dilute and use Grinder mechanical dissociation treatment for 8 hours to obtain 6% dryness of sucrose polysaccharide nanofiber slurry (calculated as (9/6%)-(45-9)=114g, water density is 1g/cm ³ , so 114mL), sealed and refrigerated;

(4) Cationic modification of sugarcane pith polysaccharide nanofibers

Dissolve 60 mg of trimethyl[3-(triethoxysilyl)propyl]ammonium chloride (TTPAC) in 500 mL of N,N-dimethylacetamide (DMAC) in an ice-water bath, and add to the Put 100 mg of sucrose polysaccharide nanofiber (PNF) slurry into the system, place it in a nitrogen environment at 60°C and stir for 25 hours. After the reaction is completed, place the reaction solution in a dialysis bag (molecular weight cut-off: 5kDa) and dialyze with deionized water After 7 days and repeated water changes, the liquid in the dialysis bag was evaporated to dryness under reduced pressure, and placed in an oven at 60°C for 8 hours to obtain cationic polysaccharide nanofibers (CPNF);

(5) Realization of nanofibrous gel film of quaternary ammonium salt polysaccharide in sugarcane pith

Mix 100mg of CPNF, 500mg of tartaric acid, and 0.1mL of hydrochloric acid in 300mL of water, and then put them in an oil bath at 115°C for 1 hour. Dry the polytetrafluoroethylene plate in an oven at 60°C for 10 hours. The dried cellulose film and the polytetrafluoroethylene plate are soaked and washed in a glycerin bath with a mass concentration of 5% for 72 hours. The glycerin bath is changed 5 times a day. The film and the mold were dried in an oven at 60°C for 3 hours, and the film was taken out and pressed in a vulcanizer with a pressure of 100°C and 300kg for 7 hours to obtain a nanofiber gel film of quaternary ammonium salt polysaccharide;

(6) Properties of the finished product of sugarcane pulp quaternary ammonium salt polysaccharide nanofiber gel film

Determination of the physical strength of the film: according to the ASTM D638 test method, the tensile strength and elongation at break are 2.0MPa and 30% respectively;

Determination method of water retention performance of film: measure and take several 50mg dry gel films respectively immersed in 100mL deionized water, let stand at 25°C water temperature for 72h, after adsorption balance, take out the film, wipe off the surface liquid of the film, use electronic balance Measure the weight of the film before and after water absorption, and calculate the maximum swelling degree to be 171g/g;

The antibacterial performance test method of the film: the film method refers to the standard QB2591, the inhibition rate of the gel film to Escherichia coli is 99.99%, and the inhibition rate to Staphylococcus aureus is 99.99%.

Claims (2)

1. The preparation method of the nanofiber gel membrane based on the bagasse pith quaternary ammonium salt polysaccharide is characterized by comprising the following specific operations:

(1) Sieving the air-dried bagasse through a sieve with 50-100 meshes to obtain bagasse;

(2) Adding 400-800 mL of deionized water, 7.5-15 g of sodium chlorite, 5-10 mL of glacial acetic acid and 1.5-10 mg of 2-aminocyclohexylcarboxylic acid into 10-20 g of sugarcane pith, uniformly mixing, placing the mixture in a constant temperature water bath at 80-85 ℃ for 0.5-1.5 h, adding 5-10 g of sodium chlorite and 3-7 mL of glacial acetic acid again for reacting for 0.5-1.5 h, repeating the operation for 3-5 times, cooling at room temperature after the reaction is finished, transferring the reactant into a nylon mesh bag with 1500-2500 meshes, soaking and washing with deionized water until the pH value of the material is neutral, and removing water to obtain sugarcane pith polysaccharide;

(3) Adding water into the bagasse pulp polysaccharide for dilution, and adopting a mechanical dissociation mode to treat for 4-8 hours to prepare bagasse pulp polysaccharide nanofiber slurry with 2-6% dryness, and freeze-drying;

(4) Dissolving 3-60 mg of trimethyl [3- (triethoxysilyl) propyl ] ammonium chloride in 50-500 mL of N, N-dimethylacetamide in an ice water bath, then adding 50-100 mg of bagasse pulp polysaccharide nanofiber slurry, placing the mixture in a 30-60 ℃ and nitrogen environment, stirring for 24-48 h, placing the reaction solution in a dialysis bag, dialyzing for 3-7 days with deionized water, repeatedly changing water, evaporating the liquid in the dialysis bag to dryness under reduced pressure, and placing the solution in a baking oven at 30-60 ℃ for 8-12 h to obtain cationic polysaccharide nanofibers;

(5) Uniformly mixing 50-100 mg of cationic polysaccharide nanofibers, 100-500 mg of tartaric acid and 0.01-0.1 mL of hydrochloric acid in 50-300 mL of water, then placing the mixture in an oil bath at 75-115 ℃ for reaction for 1-5 h, then fully removing bubbles in a vacuum drying box, pouring the mixture into a polytetrafluoroethylene plate, drying at 50-60 ℃ for 10-13 h, placing the dried cellulose film and the polytetrafluoroethylene plate in a glycerol bath with the mass concentration of 3-5% for soaking and washing for 24-72 h, changing glycerol for 3-5 times each day, drying the cleaned film and a mould at 40-60 ℃ for 3-7 h, taking out the film, and hot-pressing the film in a vulcanizing machine for 5-7 h by using the pressure of 60-100 ℃ and 200-300 kg to obtain the nanofiber gel film of the bagasse quaternary ammonium salt polysaccharide.

2. The method for preparing a nanofiber gel membrane based on a quaternary ammonium salt polysaccharide of bagasse pith according to claim 1, wherein: the cut-off molecular weight of the dialysis bag is 2-5 kDa.