A method for synthesizing a halamine quaternary ammonium salt antibacterial cellulose membrane

Abstract

The application relates to the technical field of antibacterial fiber membranes, and discloses a synthesis method of a halamine quaternary ammonium salt antibacterial cellulose membrane. A halamine quaternary ammonium salt antibacterial agent with double antibacterial functions is introduced on the surface of cellulose through surface grafting. Hexamethylene diisocyanate is used as a crosslinking agent to bond the hydroxyl groups of the antibacterial agent with the hydroxyl groups on the surface of cellulose, and then the halamine quaternary ammonium salt antibacterial agent is fixed on the fiber surface, so that the antibacterial property and stability of the antibacterial agent are greatly improved, and the problem that the antibacterial agent is prone to loss during use is avoided. After multiple water washing, the active chlorine of the quaternary ammonium salt and the halamine can still play the high-efficiency antibacterial effect. The crosslinking action makes the cellulose fiber molecules closely combined and not easy to be damaged. Meanwhile, the carboxyl groups in the molecular structure have hydrophilic action and good compatibility with the cellulose fiber, so that the hydrophilicity and the long-lasting antibacterial capacity of the fiber membrane are further improved.

Description

Technical Field

[0001] This invention relates to the field of antibacterial fiber membrane technology, specifically a method for synthesizing a haloamine quaternary ammonium salt antibacterial cellulose membrane. Background Technology

[0002] Cellulose is one of the most abundant natural polymer resources in nature, characterized by high degree of polymerization, good molecular orientation, and strong chemical stability. Cellulose fiber is a natural polymer material with huge production volume in nature, possessing the advantages of large specific surface area and biodegradability. It is widely used in clothing, bedding, bath products, and many industrial fields. At the same time, due to the good hydrophilicity of cellulose fiber, cellulose fabrics are more likely to become a breeding ground for bacteria. With the increasing awareness of health, the demand for antibacterial and antiviral textiles is increasing. Due to the widespread use of cellulose products in daily life, the antibacterial durability of cellulose fiber has become a current research hotspot.

[0003] Currently, the methods for antibacterial fiber production involve coating the outer surface with an inorganic antibacterial layer. Common inorganic antibacterial agents are generally inorganic compounds of metal cations such as silver ions or metal nanoparticles, which have advantages such as good heat resistance, long duration of action, and low likelihood of developing drug resistance. However, they face environmental and human health issues. Furthermore, the antibacterial layer is easily damaged by external friction on the fiber, and the interaction between the fiber and the antibacterial agent is mainly van der Waals forces, which are relatively weak, leading to easy loss of the antibacterial agent. Existing technologies also employ methods such as impregnation, padding, coating, or spraying to apply antibacterial agents to the fiber to produce antibacterial fibers. For example, impregnating cellulose fibers with a nano-silver solution produces nano-silver antibacterial cellulose fibers. While these antibacterial fibers possess some antibacterial function, the antibacterial components have low stability and essentially lose their antibacterial function after several washes.

[0004] Cellulose fibers have a large number of hydroxyl groups on their surface, making them easier to modify and giving them an advantage over other carrier materials. This invention prepares a halogenated quaternary ammonium salt antibacterial agent and reacts it with the hydroxyl groups on the surface of cellulose through chemical grafting. This fixes the small molecule antibacterial agent on the fiber surface, fully utilizing the dual antibacterial effects of halogenated amines and quaternary ammonium salts. It also avoids the phenomenon of antibacterial agent loss during use and significantly improves the antibacterial durability of the fiber membrane. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a method for synthesizing a haloamine quaternary ammonium salt antibacterial cellulose membrane, which avoids the easy loss of antibacterial agent during use and greatly improves its antibacterial properties and stability.

[0006] The above-mentioned objective of this invention is achieved through the following technical solution:

[0007] A method for synthesizing a haloamine quaternary ammonium salt antibacterial cellulose membrane, the synthesis method comprising the following steps:

[0008] (1) Add cellulose fibers and N,N-dimethylacetamide to the reaction flask, stir evenly at a speed of 4000-6000 r / min, and add the following: The intermediate of haloamine carboxylic acid pyridine quaternary ammonium salt and hexamethylene diisocyanate were stirred and reacted. After the reaction was completed, the solution was cast into a film, degassed, dried, washed with water and ethanol, and dried to obtain a cellulose membrane containing haloamine pyridine quaternary ammonium salt.

[0009] (2) Prepare an aqueous solution of sodium hypochlorite, adjust the pH to neutral with concentrated sulfuric acid, then put the cellulose membrane containing haloamine pyridine quaternary ammonium salt into the aqueous solution of sodium hypochlorite, immerse it at 20-35℃ for 2-5 hours, wash with deionized water, and dry to obtain the antibacterial cellulose membrane of haloamine quaternary ammonium salt.

[0010] Furthermore, in step (1), the mass of the haloamine carboxylic acid pyridine quaternary ammonium salt intermediate and the hexamethylene diisocyanate are 0.5-5% and 1.2-15% of the mass of the cellulose fiber, respectively.

[0011] Furthermore, in step (1), the reaction temperature is 60-75℃ and the reaction time is 2-4h.

[0012] Furthermore, the mass fraction of the sodium hypochlorite aqueous solution in step (2) is 5-10%.

[0013] Furthermore, the synthesis method of the haloamine carboxylic acid pyridine quaternary ammonium salt intermediate in step (1) is carried out according to the following steps:

[0014] S1. Isonicotinic acid and acetonitrile were added to a reaction flask and stirred until homogeneous. Epichlorohydrin was then added, and the mixture was stirred to react. After the reaction was completed, the mixture was concentrated under reduced pressure and recrystallized from ethanol to obtain the epoxy carboxylic acid pyridine quaternary ammonium salt intermediate. The preparation process is as follows:

[0015]

[0016] S2. Add the epoxy carboxylic acid pyridine quaternary ammonium salt intermediate, hydroxyethyl hydantoin, and tetrahydrofuran to a reaction flask. After stirring evenly, add potassium hydroxide and react at 25-40℃ for 5-10 hours. Adjust the pH with concentrated hydrochloric acid, concentrate under reduced pressure, and recrystallize from ethanol to obtain the haloamine carboxylic acid pyridine quaternary ammonium salt intermediate. The preparation process is as follows:

[0017]

[0018] Furthermore, in step S1, the mass of epichlorohydrin is 160-210% of the mass of isonicotinic acid.

[0019] Furthermore, in step S1, the reaction temperature is 20-35℃ and the reaction time is 18-36h.

[0020] Furthermore, in step S2, the mass of hydroxyethyl hydantoin and potassium hydroxide are 105-130% and 70-120% of the mass of the epoxycarboxylic acid pyridine quaternary ammonium salt intermediate, respectively.

[0021] Furthermore, in step S2, the pH is adjusted to 3-5 using concentrated hydrochloric acid.

[0022] By adopting the above technical solution, the beneficial effects of the present invention are as follows:

[0023] This invention first involves a quaternization reaction between isonicotinic acid and epichlorohydrin to generate an epoxy carboxylic acid pyridine quaternary ammonium salt intermediate. Then, the epoxy group of this intermediate reacts with the hydroxyl group of hydroxyethyl hydantoin in the presence of potassium hydroxide to obtain a haloamine carboxylic acid pyridine quaternary ammonium salt intermediate. Next, hexamethylene diisocyanate is used as a crosslinking agent to bond the hydroxyl groups of the haloamine carboxylic acid pyridine quaternary ammonium salt intermediate to the hydroxyl groups on the surface of cellulose fibers. After casting, a cellulose membrane containing haloamine pyridine quaternary ammonium salt is obtained. Finally, the cellulose membrane containing haloamine pyridine quaternary ammonium salt is impregnated in an aqueous sodium hypochlorite solution to obtain a haloamine quaternary ammonium salt antibacterial cellulose membrane with dual antibacterial properties.

[0024] The antibacterial cellulose membrane containing pyridine quaternary ammonium salts has anionic structures on its cellulose fiber surface. Therefore, quaternary ammonium salt antibacterial agents can be adsorbed onto the surface of the cellulose membrane through electrostatic adsorption, drawing bacteria into its internal pores, causing the bacterial biofilm to wrinkle, damaging the cell membrane, and leading to bacterial death. The antibacterial cellulose membrane also contains N-Cl bonds, which can release free, strongly oxidizing chloride ions to combine with the amino groups of bacterial cell wall proteins, thereby destroying the protein structure, causing the bacterial cell wall to rupture and die. After sterilization, the N-Cl bonds are converted into NH bonds, but can be re-halogenated back into N-Cl bonds, exhibiting broad-spectrum antibacterial and regenerative bactericidal capabilities.

[0025] By using a surface grafting method, quaternary ammonium salt polymers with antibacterial functions are introduced onto the surface of cellulose fiber membranes. Hexamethylene diisocyanate is used as a crosslinking agent to bond the hydroxyl groups of small molecule antibacterial agents to the hydroxyl groups on the cellulose surface, grafting haloamine quaternary ammonium salt antibacterial agents onto the cellulose surface, thereby fixing the small molecule antibacterial agents. This fully utilizes the dual antibacterial effects of haloamines and quaternary ammonium salts, significantly improving its antibacterial properties and stability, reducing the loss of antibacterial agents and pollution to the surrounding environment, and avoiding the problem that conventional antibacterial agents are simply adsorbed on the cellulose surface and easily lost during use.

[0026] The haloamine quaternary ammonium salt antibacterial cellulose membrane prepared by this invention has strong water washing stability and antibacterial regeneration. After multiple water washings, the active chlorine of the quaternary ammonium salt and haloamine can still exert its highly efficient antibacterial effect. This is because the crosslinking agent hexamethylene diisocyanate acts to link the hydroxyl groups of the haloamine carboxylic acid pyridine quaternary ammonium salt intermediate with the hydroxyl groups of cellulose fibers, making the cellulose fiber molecules tightly bound and not easily damaged. At the same time, the carboxyl groups in the molecular structure have a hydrophilic effect and good compatibility with cellulose fibers, which can fix the small molecule antibacterial agent on the fiber surface, further improving the hydrophilicity and long-lasting antibacterial ability of the cellulose membrane. Detailed Implementation

[0027] To make the technical means, objectives, and effects of this invention readily understandable, the invention is further illustrated below with reference to specific embodiments. However, these embodiments are merely preferred embodiments and not exhaustive. Other embodiments obtained by those skilled in the art based on the embodiments described herein without inventive effort are all within the scope of protection of this invention.

[0028] Example 1

[0029] (1) Add 50g of isonicotinic acid and acetonitrile to the reaction flask, stir evenly, add 100g of epichlorohydrin, react at 25℃ for 25h, concentrate under reduced pressure, recrystallize from ethanol to obtain the epoxy carboxylic acid pyridine quaternary ammonium salt intermediate.

[0030] (2) Add 35g of epoxy carboxylic acid pyridine quaternary ammonium salt intermediate, 42g of hydroxyethyl hydantoin and tetrahydrofuran to the reaction flask, stir evenly, add 38g of potassium hydroxide, react at 35℃ for 8h, adjust the pH to 4 with concentrated hydrochloric acid, concentrate under reduced pressure, recrystallize with ethanol to obtain haloamine carboxylic acid pyridine quaternary ammonium salt intermediate.

[0031] (3) Add 100g of cellulose fiber and N,N-dimethylacetamide to the reaction flask, stir evenly at 5500r / min, and add 0.5g of the following: The intermediate of haloamine carboxylic acid pyridine quaternary ammonium salt and 1.2 g of hexamethylene diisocyanate were reacted at 65 °C for 3 h. The solution was then cast into a film, degassed, dried, washed with water and ethanol, and dried to obtain a cellulose membrane containing haloamine pyridine quaternary ammonium salt.

[0032] (4) Prepare an 8% sodium hypochlorite aqueous solution, adjust the pH to neutral with concentrated sulfuric acid, then put the cellulose membrane containing haloamine pyridine quaternary ammonium salt into the sodium hypochlorite aqueous solution, soak it at 25°C for 4 hours, wash it with deionized water, and dry it to obtain the haloamine quaternary ammonium salt antibacterial cellulose membrane.

[0033] Example 2

[0034] (1) Add 15g of isonicotinic acid and acetonitrile to the reaction flask, stir evenly, add 31g of epichlorohydrin, react at 20℃ for 18h, concentrate under reduced pressure, recrystallize from ethanol to obtain the epoxy carboxylic acid pyridine quaternary ammonium salt intermediate.

[0035] (2) Add 10g of epoxy carboxylic acid pyridine quaternary ammonium salt intermediate, 13g of hydroxyethyl hydantoin and tetrahydrofuran to the reaction flask, stir evenly, add 12g of potassium hydroxide, react at 25℃ for 5h, adjust the pH to 3 with concentrated hydrochloric acid, concentrate under reduced pressure, recrystallize with ethanol to obtain haloamine carboxylic acid pyridine quaternary ammonium salt intermediate.

[0036] (3) Add 100g of cellulose fiber and N,N-dimethylacetamide to the reaction flask, stir for 5min at 4000r / min, and add 1.6g of the following: The intermediate of haloamine carboxylic acid pyridine quaternary ammonium salt and 5g of hexamethylene diisocyanate were reacted at 60℃ for 2h. The solution was then cast into a film, degassed, dried, washed with water and ethanol, and dried to obtain a cellulose membrane containing haloamine pyridine quaternary ammonium salt.

[0037] (4) Prepare a 5% sodium hypochlorite aqueous solution, adjust the pH to neutral with concentrated sulfuric acid, then put the cellulose membrane containing haloamine pyridine quaternary ammonium salt into the sodium hypochlorite aqueous solution, soak it at 20°C for 2 hours, wash it with deionized water, and dry it to obtain the haloamine quaternary ammonium salt antibacterial cellulose membrane.

[0038] Example 3

[0039] (1) Add 40g of isonicotinic acid and acetonitrile to the reaction flask, stir evenly, add 64g of epichlorohydrin, react at 35℃ for 36h, concentrate under reduced pressure, recrystallize from ethanol to obtain the epoxy carboxylic acid pyridine quaternary ammonium salt intermediate.

[0040] (2) Add 25g of epoxy carboxylic acid pyridine quaternary ammonium salt intermediate, 26g of hydroxyethyl hydantoin and tetrahydrofuran to the reaction flask, stir evenly, add 17g of potassium hydroxide, react at 40℃ for 10h, adjust the pH to 5 with concentrated hydrochloric acid, concentrate under reduced pressure, recrystallize with ethanol to obtain haloamine carboxylic acid pyridine quaternary ammonium salt intermediate.

[0041] (3) Add 100g of cellulose fiber and N,N-dimethylacetamide to the reaction flask, stir at 6000r / min for 10min, and add 2.6g of the following structure: The intermediate of haloamine carboxylic acid pyridine quaternary ammonium salt and 8g of hexamethylene diisocyanate were reacted at 75℃ for 4h. The solution was then cast into a film, degassed, dried, washed with water and ethanol, and dried to obtain a cellulose membrane containing haloamine pyridine quaternary ammonium salt.

[0042] (4) Prepare a sodium hypochlorite aqueous solution with a mass fraction of 10%, adjust the pH to neutral with concentrated sulfuric acid, then put the cellulose membrane containing haloamine pyridine quaternary ammonium salt into the sodium hypochlorite aqueous solution, soak it at 35°C for 5 hours, wash it with deionized water, and dry it to obtain the haloamine quaternary ammonium salt antibacterial cellulose membrane.

[0043] Example 4

[0044] (1) Add 5g of isonicotinic acid and acetonitrile to the reaction flask, stir evenly, add 8g of epichlorohydrin, react at 30℃ for 30h, concentrate under reduced pressure, recrystallize from ethanol to obtain the epoxy carboxylic acid pyridine quaternary ammonium salt intermediate.

[0045] (2) Add 3g of epoxy carboxylic acid pyridine quaternary ammonium salt intermediate, 3.7g of hydroxyethyl hydantoin and tetrahydrofuran to the reaction flask, stir evenly, add 2.7g of potassium hydroxide, react at 30℃ for 7h, adjust the pH to 4 with concentrated hydrochloric acid, concentrate under reduced pressure, recrystallize with ethanol to obtain haloamine carboxylic acid pyridine quaternary ammonium salt intermediate.

[0046] (3) Add 100g of cellulose fiber and N,N-dimethylacetamide to the reaction flask, stir for 10min at 4500r / min, and add 3.8g of the following: The intermediate of haloamine carboxylic acid pyridine quaternary ammonium salt and 11g of hexamethylene diisocyanate were reacted at 65℃ for 3h. The solution was then cast into a film, degassed, dried, washed with water and ethanol, and dried to obtain a cellulose membrane containing haloamine pyridine quaternary ammonium salt.

[0047] (4) Prepare an 8% sodium hypochlorite aqueous solution, adjust the pH to neutral with concentrated sulfuric acid, then put the cellulose membrane containing haloamine pyridine quaternary ammonium salt into the sodium hypochlorite aqueous solution, soak it at 35°C for 2 hours, wash it with deionized water, and dry it to obtain the haloamine quaternary ammonium salt antibacterial cellulose membrane.

[0048] Example 5

[0049] (1) Add 25g of isonicotinic acid and acetonitrile to the reaction flask, stir evenly, add 45g of epichlorohydrin, react at 20℃ for 36h, concentrate under reduced pressure, recrystallize from ethanol to obtain the epoxy carboxylic acid pyridine quaternary ammonium salt intermediate.

[0050] (2) Add 20g of epoxy carboxylic acid pyridine quaternary ammonium salt intermediate, 23g of hydroxyethyl hydantoin and tetrahydrofuran to the reaction flask, stir evenly, add 16g of potassium hydroxide, react at 40℃ for 9h, adjust the pH to 3 with concentrated hydrochloric acid, concentrate under reduced pressure, recrystallize with ethanol to obtain haloamine carboxylic acid pyridine quaternary ammonium salt intermediate.

[0051] (3) Add 100g of cellulose fiber and N,N-dimethylacetamide to the reaction flask, stir for 5min at 6000r / min, and add 5g of the following structure: The intermediate of haloamine carboxylic acid pyridine quaternary ammonium salt and 15g of hexamethylene diisocyanate were reacted at 60℃ for 4h. The solution was cast into a film, degassed, dried, washed with water and ethanol, and dried to obtain a cellulose membrane containing haloamine pyridine quaternary ammonium salt.

[0052] (4) Prepare a sodium hypochlorite aqueous solution with a mass fraction of 10%, adjust the pH to neutral with concentrated sulfuric acid, then put the cellulose membrane containing haloamine pyridine quaternary ammonium salt into the sodium hypochlorite aqueous solution, immerse it at 25°C for 45 h, wash it with deionized water, and dry it to obtain the haloamine quaternary ammonium salt antibacterial cellulose membrane.

[0053] Comparative Example 1

[0054] (1) Add 100g of cellulose fiber and N,N-dimethylacetamide to the reaction flask, stir evenly at 5500r / min, and add 0.5g of the following: Hydroxyethyl hydantoin and 1.2 g hexamethylene diisocyanate were reacted at 65 °C for 3 h. The solution was then cast into a film, degassed, dried, washed with water and ethanol, and dried again to obtain a cellulose membrane containing halogenated amines.

[0055] (2) Prepare an 8% sodium hypochlorite aqueous solution, adjust the pH to neutral with concentrated sulfuric acid, then put the halogenated amine-containing cellulose membrane into the sodium hypochlorite aqueous solution, soak it at 25°C for 4 hours, wash it with deionized water, and dry it to obtain an antibacterial cellulose membrane.

[0056] Comparative Example 2

[0057] Add 100g of cellulose fiber and N,N-dimethylacetamide to a reaction flask, stir until homogeneous at 5500 rpm, and then add 0.5g of the following structural formula: The epoxy carboxylic acid pyridine quaternary ammonium salt intermediate was reacted at 65°C for 5 hours, and the solution was cast into a film, degassed, dried, washed with water and ethanol, and dried again to obtain a quaternary ammonium salt cellulose film.

[0058] Comparative Example 3

[0059] Cellulose fibers and N,N-dimethylacetamide were added to a reaction flask and stirred until homogeneous at 5500 r / min. The solution was then cast into a film, degassed, dried, washed with water and ethanol, and dried again to obtain a cellulose membrane.

[0060] Antibacterial rate test: The test was conducted using the shaking method. Cultured *Escherichia coli* and *Staphylococcus aureus* were diluted in PBS buffer to a bacterial concentration of 2 × 10⁻⁶. 7 -4×107 CFU / mL, then 0.5 mL of bacterial suspension was added to 4.5 mL of PBS buffer, and 1 mg of the antibacterial cellulose membrane to be tested (Examples 1-5, Comparative Examples 1-2) was added as the experimental group, with the cellulose membrane of Comparative Example 3 as the blank group; the mixture was incubated at a constant temperature with shaking for 24 h, then 0.5 mL of bacterial suspension was taken from each test tube and added to a test tube containing 4.5 mL of PBS buffer. After shaking, 0.5 mL of bacterial suspension was taken from the test tube and added to a test tube containing 4.5 mL of PBS buffer. This process was repeated 10 times. Then, 0.5 mL of the bacterial suspension was taken from each test tube and added to a 15 mL agar plate. The bacterial suspension was evenly distributed throughout the plate using a glass spreader. The plate was inverted and incubated in a 37°C constant temperature incubator for 24 h. After incubation, the colony count was performed and the antibacterial rate of the cellulose membrane was calculated.

[0061] Antibacterial rate (%) = (AB) / A, where A is the number of colonies in the blank group and B is the number of colonies in the experimental group.

[0062]

[0063] As shown in the test results above, with the increase of the content of haloamine carboxylic acid pyridine quaternary ammonium salt intermediate in cellulose membrane, the content of quaternary ammonium salt and the amount of active chlorine that can be released after chlorination also increase. The antibacterial rate against Escherichia coli and Staphylococcus aureus gradually increases, indicating that the cellulose membrane after grafting modification has good antibacterial properties. In Example 4, the antibacterial rates against Escherichia coli and Staphylococcus aureus reached 99.99% and 100%, respectively. This is because, on the one hand, the antibacterial cellulose membrane contains a quaternary ammonium salt structure with cations, while the cellulose surface has anions. Through electrostatic adsorption, bacteria are drawn into its internal pores, causing the bacterial biofilm to wrinkle, destroying the cell membrane and leading to bacterial death. On the other hand, after the halogenated amines in the fiber membrane structure are chlorinated with sodium hypochlorite, the Cl atoms in the N-Cl bond have oxidizing properties. During their contact with bacteria, the oxidized chlorine is transferred to the acceptor site of the bacteria, oxidizing the thiol group or chlorinating the amino group in the protein, thereby causing the microorganisms to become inactive. Grafted fibers with dual antibacterial mechanisms can quickly adsorb bacteria onto the fiber surface through strong adsorption. The halogenated amines on the fiber surface can release a high concentration of active chlorine, which can quickly kill the adsorbed live bacteria, thereby greatly improving the antibacterial performance. Grafting and fixing the halogenated amine quaternary ammonium salt onto the cellulose surface can significantly improve its antibacterial properties and stability, reduce the loss of antibacterial agents and pollution to the surrounding environment.

[0064] Comparative Example 1 does not contain a pyridine quaternary ammonium salt cationic structure. Its antibacterial rates against Escherichia coli and Staphylococcus aureus are 82.52% and 85.43%, respectively, showing some antibacterial effect, but not as good as the example. Comparative Example 2 is an epoxy quaternary ammonium salt cellulose membrane. The epoxy groups can react with the hydroxyl groups on the cellulose surface to form bonds. Its antibacterial rates against Escherichia coli and Staphylococcus aureus are 62.40% and 57.13%, respectively, showing poor antibacterial performance.

[0065] Water washing stability test: The prepared cellulose membrane was immersed in deionized water for 3 hours, taken out and dried. After repeating the process 20 and 50 times respectively, the antibacterial rate against Escherichia coli and Staphylococcus aureus was tested by the shaking method.

[0066]

[0067] The test results in the table above show that with increasing washing cycles, the antibacterial rates of the antibacterial cellulose membrane against Escherichia coli and Staphylococcus aureus decreased compared to the unwashed membrane, but the decrease was not significant. After 20 washes, the antibacterial rate against Escherichia coli remained above 90%, and after 50 washes, the antibacterial rate against Staphylococcus aureus remained above 90%, with the highest antibacterial rate reaching 99.99%. This indicates that even after multiple washes, the antibacterial rates of quaternary ammonium salts and halogenated amines... Active chlorine can still exert its highly efficient antibacterial effect, giving the prepared haloamine quaternary ammonium salt antibacterial cellulose membrane strong water wash stability and antibacterial regeneration. This is because the crosslinking agent hexamethylene diisocyanate acts to link the hydroxyl groups of the haloamine carboxylic acid pyridine quaternary ammonium salt intermediate with the hydroxyl groups of cellulose fibers, making the cellulose molecules tightly bound and not easily damaged. At the same time, the carboxyl groups in the molecular structure have a hydrophilic effect and good compatibility with cellulose fibers, which can fix small molecule antibacterial agents on the fiber surface, greatly improving the antibacterial durability and stability.

[0068] Hydrophilicity test: The water contact angle of the cellulose membrane under test was measured using a water contact angle meter. Each membrane sample was tested 3 times and the average value was taken.

[0069]

[0070] The water contact angle reflects the hydrophilicity of the membrane surface. As shown in the test results in the table above, the water contact angle of the pure cellulose membrane in Comparative Example 3 is 61.2°, while that in Example 5 is 48.3°. This indicates that the hydrophilicity of the cellulose membrane in Example 5 is better than that in Comparative Example 3. This is because the antibacterial cellulose membrane of the haloamine quaternary ammonium salt in the example contains carboxyl groups with strong hydrophilic properties, which have good compatibility with cellulose and help improve the hydrophilicity of the cellulose membrane. The antibacterial cellulose membrane of Comparative Example 1 does not contain carboxylic acid groups, and its water contact angle is 66.1°, indicating poor hydrophilicity.

[0071] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for synthesizing a haloamine quaternary ammonium salt antibacterial cellulose membrane, characterized in that, The synthesis method is carried out according to the following steps: (1) Add cellulose fibers and N,N-dimethylacetamide to the reaction flask, stir evenly at a speed of 4000-6000 r / min, and add the following: The intermediate of haloamine carboxylic acid pyridine quaternary ammonium salt and hexamethylene diisocyanate were stirred and reacted. After the reaction was completed, the solution was cast into a film, degassed, dried, washed with water and ethanol, and dried to obtain a cellulose film containing haloamine pyridine quaternary ammonium salt. (2) Prepare an aqueous solution of sodium hypochlorite, adjust the pH to neutral with concentrated sulfuric acid, then put the cellulose membrane containing haloamine pyridine quaternary ammonium salt into the aqueous solution of sodium hypochlorite, immerse it at 20-35℃ for 2-5 hours, wash it with deionized water, and dry it to obtain the antibacterial cellulose membrane of haloamine quaternary ammonium salt. The synthesis method of the haloamine carboxylic acid pyridine quaternary ammonium salt intermediate in step (1) is carried out according to the following steps: S1. Add isonicotinic acid and acetonitrile to the reaction flask, stir well, add epichlorohydrin, stir to react, after the reaction is completed, concentrate under reduced pressure, recrystallize from ethanol to obtain the epoxy carboxylic acid pyridine quaternary ammonium salt intermediate. S2. Add the epoxy carboxylic acid pyridine quaternary ammonium salt intermediate, hydroxyethyl hydantoin and tetrahydrofuran to the reaction flask, stir well, add potassium hydroxide, react at 25-40℃ for 5-10 h, adjust the pH with concentrated hydrochloric acid, concentrate under reduced pressure, recrystallize with ethanol to obtain the haloamine carboxylic acid pyridine quaternary ammonium salt intermediate.

2. The method for synthesizing the haloamine quaternary ammonium salt antibacterial cellulose membrane according to claim 1, characterized in that, In step (1), the mass of the haloamine carboxylic acid pyridine quaternary ammonium salt intermediate and the hexamethylene diisocyanate are 0.5-5% and 1.2-15% of the mass of cellulose fiber, respectively.

3. The method for synthesizing the haloamine quaternary ammonium salt antibacterial cellulose membrane according to claim 1, characterized in that, The reaction temperature in step (1) is 60-75℃ and the reaction time is 2-4h.

4. The method for synthesizing the haloamine quaternary ammonium salt antibacterial cellulose membrane according to claim 1, characterized in that, The sodium hypochlorite aqueous solution in step (2) has a mass fraction of 5-10%.

5. The method for synthesizing the haloamine quaternary ammonium salt antibacterial cellulose membrane according to claim 1, characterized in that, In step S1, the mass of epichlorohydrin is 160-210% of the mass of isonicotinic acid.

6. The method for synthesizing the haloamine quaternary ammonium salt antibacterial cellulose membrane according to claim 1, characterized in that, In step S1, the reaction temperature is 20-35℃ and the reaction time is 18-36h.

7. The method for synthesizing the haloamine quaternary ammonium salt antibacterial cellulose membrane according to claim 1, characterized in that, In step S2, the mass of hydroxyethyl hydantoin and potassium hydroxide are 105-130% and 70-120% of the mass of the epoxy carboxylic acid pyridine quaternary ammonium salt intermediate, respectively.

8. The method for synthesizing the haloamine quaternary ammonium salt antibacterial cellulose membrane according to claim 1, characterized in that, In step S2, the pH is adjusted to 3-5 using concentrated hydrochloric acid.

Images