Chitosan grafted cellulose-based antibacterial material and preparation method thereof

Abstract

The present invention discloses a chitosan grafted cellulose-based antibacterial material and a preparation method thereof, and relates to the technical field of grafting and preparing polymer antibacterial materials. A chitosan grafted cellulose-based antibacterial material is made of the following raw materials in parts by mass: 90-100 parts of cellulose matrix, 10-60 parts of chitosan, 2-20 parts of epoxy cross-linking agent, 300-350 parts of acidic solvent, 5-30 parts of alkaline neutralizer, 1-10 parts of plasticizer, and 0-15 parts of antibacterial agent. The present invention is carried out by grafting chitosan and cellulose and adding a specific antibacterial agent, so that the antibacterial effect of the material on common bacteria such as Escherichia coli and Staphylococcus aureus is greatly improved, bacterial growth can be more effectively inhibited, and the demand for efficient antibacterial performance in practical applications is met.

Description

Technical Field

[0001] The present invention relates to the technical field of grafting preparation of high molecular antibacterial materials, and in particular to a chitosan grafted cellulose-based antibacterial material and a preparation method thereof. Background Art

[0002] In the field of modern materials science, the research and development of antimicrobial materials is of great significance. With the improvement of people's living standards and the enhancement of hygiene awareness, the demand for materials that can effectively inhibit the growth of microorganisms, prevent infection and deterioration is growing.

[0003] Traditional antimicrobial materials have numerous shortcomings. For one thing, many inorganic antimicrobial materials, such as silver ion compounds, while effective, are relatively expensive, and the extensive use of silver ions can pose potential risks to the environment and human health, such as water pollution and the development of bacterial resistance. Furthermore, some organic antimicrobial agents suffer from poor stability and durability, making it difficult to ensure their dispersion and durability within materials, leading to a significant decrease in their antimicrobial effectiveness over time.

[0004] Cellulose, as a natural polymer material, is widely available, renewable, and has good biocompatibility and degradability. However, the antibacterial properties of pure cellulose materials are relatively limited, making it difficult to meet the antibacterial needs in practical applications. Chitosan is a natural polysaccharide with good antibacterial activity. Its antibacterial mechanism mainly lies in its ability to bind to negatively charged groups on the surface of bacterial cell walls, destroying the cell wall structure and thereby inhibiting bacterial growth. However, chitosan has poor solubility in water and poor mechanical properties when used alone, which to some extent limits its widespread application in the field of antibacterial materials.

[0005] The composite modification of chitosan and cellulose to prepare chitosan-grafted cellulose-based antibacterial materials is expected to give full play to the advantages of both. Some related research reports have been published, but the existing preparation processes still have some problems. For example, some preparation methods have harsh reaction conditions and require extreme environments such as high temperature, high pressure, or strong acid and strong base, which not only increases production costs but may also cause damage to material properties. In addition, some preparation processes are complicated and cumbersome, making it difficult to achieve large-scale production and unable to meet market demand.

[0006] In summary, the development of a chitosan-grafted cellulose-based antibacterial material with excellent antibacterial properties, low cost, simple preparation process and environmental friendliness has extremely urgent practical significance for promoting the widespread application of antibacterial materials in many fields such as medical dressings, food packaging and daily necessities. The present invention is proposed based on this background. Summary of the Invention

[0007] The purpose of the present invention is to provide a chitosan-grafted cellulose-based antibacterial material with excellent antibacterial properties, simple preparation process, low cost and environmental friendliness, so as to overcome the defects of the antibacterial materials in the prior art, such as poor antibacterial effect, complex preparation and high cost.

[0008] To achieve the above object, the technical solution adopted by the present invention is: a chitosan-grafted cellulose-based antibacterial material, which is made from the following raw materials in parts by weight: 90-100 parts of cellulose matrix, 10-60 parts of chitosan, 2-20 parts of epoxy crosslinking agent, 300-350 parts of acidic solvent, 5-30 parts of alkaline neutralizer, 1-10 parts of plasticizer, and 0-15 parts of antibacterial agent;

[0009] The antibacterial agent is a compound represented by Formula 1:

[0010] Formula 1;

[0011] R1 in the formula 1 is: cyano, ethyl, methyl, or propyl.

[0012] Furthermore, the cellulose matrix is ​​microcrystalline cellulose, and its degree of polymerization is between 150-375.

[0013] Furthermore, the epoxy crosslinking agent is 1,4-butanediol diglycidyl ether.

[0014] Furthermore, the deacetylation degree of the chitosan is ≥85%.

[0015] Furthermore, the acidic solvent is a 0.1 mol / L citric acid aqueous solution; and the alkaline neutralizing agent is sodium bicarbonate.

[0016] Furthermore, the plasticizer is glycerol.

[0017] Furthermore, the antibacterial agent is any one of the compounds shown in the following structures:

[0018]

[0019]

[0020] A method for preparing a chitosan-grafted cellulose-based antibacterial material comprises the following steps:

[0021] S1. The cellulose matrix is ​​added to the acidic solvent, heated to 40-80 ° C, stirred to dissolve, and the chitosan is added, and the mixture is stirred for 10-30 minutes to obtain a mixed material A;

[0022] S2. The epoxy crosslinking agent is added to the mixture A, reacted at 40-80 ° C for 1-4 hours, the alkaline neutralizing agent is added, and the pH is adjusted to 7-8 to obtain a mixture B;

[0023] S3. Add the plasticizer and antibacterial agent to the mixed material B, stir and mix for 10-20 minutes, pour into a mold, dry at 40-60°C for 6-12 hours, and demold to obtain the chitosan-grafted cellulose-based antibacterial material.

[0024] Furthermore, the reaction temperature in S2 is 50-70° C., and the reaction time is 2-3 hours.

[0025] The invention discloses an application of a chitosan-grafted cellulose-based antibacterial material in antibacterial medical dressings, food packaging films and antibacterial substrates.

[0026] Furthermore, the chitosan-grafted cellulose-based antibacterial material has an antibacterial rate of ≥99% against Escherichia coli and Staphylococcus aureus.

[0027] The core components of the chitosan-grafted cellulose antimicrobial material described in this invention include microcrystalline cellulose, which forms a three-dimensional network framework to provide mechanical strength and biodegradability. Chitosan, with a degree of deacetylation of ≥85%, binds to the negatively charged bacterial cell wall through its protonated amino groups, disrupting the integrity of the cell membrane. Under the action of an epoxy crosslinker, the two undergo a grafting reaction in the acidic environment provided by a 0.1 mol / L aqueous citric acid solution, forming a "cellulose-crosslinker-chitosan" covalent network. This overcomes the mechanical shortcomings of chitosan alone, prevents the loss of antimicrobial components caused by physical mixing, and avoids the risk of molecular chain damage associated with traditional strong acid / strong base crosslinking. The solvent and neutralizer synergistically regulate the reaction process: the mild acidic environment of the citric acid solution promotes component swelling and dissolution, while its chelation action inhibits metal ions from promoting bacterial growth. The alkaline neutralizer, sodium bicarbonate, regulates the system pH to 7-8, simultaneously performing dual functions: terminating the crosslinking reaction to prevent material embrittlement and generating CO2 bubbles within the material to form a microporous structure, significantly increasing the specific surface area and optimizing the diffusion efficiency of the antimicrobial agent. Among the functional additives, the plasticizer glycerol is inserted between polymer chains to weaken the hydrogen bonding effect, improve flexibility and processability, and avoid uneven distribution of the antimicrobial agent caused by drying and cracking; the antimicrobial agent penetrates the bacterial lipid membrane through the hydrophobic group, and together with the charge attack of chitosan, it forms a dual antimicrobial mechanism of "membrane destruction + intracellular poisoning"; finally, the microporous structure accelerates the release of glycerol from the antimicrobial agent to ensure its uniform dispersion in the matrix, achieving synergistic enhancement of the system.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. Significantly improved antibacterial performance: The present invention grafts chitosan and cellulose and adds specific antibacterial agents to greatly improve the antibacterial effect of the material on common bacteria such as Escherichia coli and Staphylococcus aureus, which can more effectively inhibit bacterial growth and meet the demand for high-efficiency antibacterial performance in practical applications.

[0030] 2. Simple and Optimized Preparation Process: Compared to traditional preparation methods, this method operates under mild reaction conditions, eliminating the need for high temperatures, high pressures, or extreme environments such as strong acids and bases, thereby reducing production costs and operational complexity. Furthermore, the preparation process is simple and easy, with fewer reaction steps, and the reaction conditions and operations of each step are relatively easy to control, making it more conducive to large-scale production, improving production efficiency, and meeting market demand.

[0031] 3. Enhanced environmental friendliness: The raw materials used in this invention are primarily natural polymer materials, cellulose and chitosan, which are widely available, renewable, and have good biocompatibility and degradability, meeting the requirements of sustainable development. Furthermore, the relatively mild solvents and reaction conditions used in the preparation process reduce the risk of environmental pollution and potential harm to the environment and human health. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the NMR image of the antibacterial agent 1 described in the present invention. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] Preparation Example 1

[0035] Preparation of antibacterial agent 1:

[0036] ;

[0037] A1: Under nitrogen atmosphere, add 10.00 g of raw material 1, 18.75 g of raw material 2, 16.73 g of potassium carbonate, 0.21 g of target carbon, 0.8 g of triphenylphosphine, and 130 g of toluene to the reaction system, stir evenly, heat to 110°C, and reflux for 12 h.

[0038] Post-treatment of A1: After the reaction, the temperature was slightly lowered, and the mixture was filtered using a silica gel cake. 200 g of water was added to the organic phase, and the mixture was extracted three times repeatedly. The organic phases were combined, dried over anhydrous magnesium sulfate, filtered, and spin-dried. The organic phases were then subjected to silica gel column chromatography using a mixture of petroleum ether and ethyl acetate as the eluent. After spin-dried, 15.98 g of intermediate 1 was obtained.

[0039] Intermediate structure identification: mass spectrum (M / Z-MS+H+): 343.

[0040] A2 charging: Under nitrogen atmosphere, add 15.98 g of intermediate 1, 19.33 g of raw material 3, 24.85 g of potassium phosphate trihydrate, 0.05 g of pyridine-2-carboxylic acid, 0.45 g of CuI and 150 g of DMSO to the reaction system, heat to 85 ° C and react for 16 h;

[0041] A2 post-treatment: The temperature of the reaction system was lowered to room temperature, the reaction mixture was extracted with aqueous ammonia solution and methyl tert-butyl ether, the organic phase was washed three times with saturated NaCl solution, the combined organic phases were spin-dried and purified on a silica gel column using a mixed solution of petroleum ether and ethyl acetate as eluent, and the solution was spin-dried to obtain 22.64 g of antibacterial agent 1.

[0042] Final product structure identification:

[0043] Mass spectrum of antimicrobial agent 1 (M / Z-MS+H+): 607;

[0044] 1HNMR Chloroform-d of antibacterial agent 1: δ8.15-8.05(m,2H),7.48-7.37(m,2H),7.27(m,2H),7.07-6.97(m,2H),6.89-6.74(m,4H),5.27(t,2H),5.11(d,1H),4.52(t,1H),4.15(m,1H),3.91(d,1H),3.78(m,1H),3.59-3.41(m,2H),3.02(m,1H),2.78(m,1H),1.81-1.62(m,1H),1.59-1.40(m,1H),1.35-1.23(m,9H),0.94(m,3H).

[0045] Preparation Example 2-Preparation Example 4

[0046] In Preparation Examples 2 to 4, antibacterial agents 2 to 4 were prepared in sequence, referring to the preparation method of Preparation Example 1, replacing raw material 1 therein, and the rest remained the same as in Preparation Example 1. The specific structure of raw material 1, antibacterial agent 2 to antibacterial agent 4 structure, and mass spectrometry (M / Z-MS+H+) data are shown in Table 1.

[0047] Table 1

[0048] Example 1

[0049] Preparation of a chitosan-grafted cellulose-based antibacterial material:

[0050] 1. Raw material formula:

[0051] Cellulose matrix: 95 parts (microcrystalline cellulose, degree of polymerization 260);

[0052] Chitosan: 35 parts (90% deacetylation);

[0053] Epoxy crosslinking agent: 1,4-butanediol diglycidyl ether, 10 parts;

[0054] Acidic solvent: 0.1 mol / L citric acid aqueous solution, 320 parts;

[0055] Alkaline neutralizer: sodium bicarbonate, 15 parts;

[0056] Plasticizer: glycerol, 5 parts;

[0057] Antibacterial agent: 15 parts, antibacterial agent 1 prepared in Preparation Example 1 is selected.

[0058] 2. Preparation method:

[0059] S1. Add 95 parts of microcrystalline cellulose to 320 parts of a 0.1 mol / L aqueous citric acid solution, heat to 60°C, and stir at 500 rpm for 30 minutes to form a uniform suspension. Then, add 35 parts of chitosan and continue stirring for 20 minutes to obtain a mixture A.

[0060] S2. 10 parts of 1,4-butanediol diglycidyl ether were added to the mixture A, and the mixture was reacted at 60 ° C for 2.5 hours, with a stirring rate of 400 rpm during the reaction. 15 parts of sodium bicarbonate were added, and the pH of the system was slowly adjusted to 7.5 to obtain a mixture B;

[0061] S3. Add 5 parts of glycerol and 15 parts of antibacterial agent 1 to mixed material B, stir and mix for 15 minutes, pour the mixture into a polytetrafluoroethylene mold, dry at 50°C for 9 hours, and after demolding, obtain a chitosan-grafted cellulose-based antibacterial material in the form of a sheet with a thickness of 0.5 mm.

[0062] Example 2-Example 4

[0063] A chitosan-grafted cellulose-based antibacterial material was prepared by referring to the preparation method of Example 1, whereby the antibacterial agent was replaced with antibacterial agent 2 to antibacterial agent 4 prepared in Preparation Examples 2 to 4, respectively, and the rest remained the same as in Example 1.

[0064] Comparative Example 1

[0065] A chitosan-grafted cellulose-based antibacterial material was prepared by referring to the preparation method of Example 1, except that the antibacterial agent was replaced with D-penicillamine, whose CAS number is 52-67-5. The rest of the preparation method remained the same as Example 1. D-penicillamine is a common antibacterial agent.

[0066] Comparative Example 2

[0067] A chitosan-grafted cellulose-based antibacterial material was prepared by referring to the preparation method of Example 1, except that the antibacterial agent was not added, and the rest of the steps were the same as those of Example 1.

[0068] Comparative Example 3

[0069] A chitosan-grafted cellulose-based antibacterial material was prepared by referring to the preparation method of Example 1, except that the mass fraction of chitosan was changed to 5 parts, and the rest remained the same as Example 1.

[0070] Comparative Example 4

[0071] A chitosan-grafted cellulose-based antibacterial material was prepared by referring to the preparation method of Example 1, except that the mass fraction of the epoxy crosslinking agent was changed to 25 parts, and the rest remained the same as Example 1.

[0072] Performance testing:

[0073] 1. Antibacterial properties were tested according to QB / T2591-2003. The test bacteria were Escherichia coli and Staphylococcus aureus. The data are shown in Table 2.

[0074] Table 2

[0075]

[0076] The antibacterial properties of the examples of the present invention were excellent overall, demonstrating extremely high antibacterial efficacy against both Escherichia coli and Staphylococcus aureus, significantly surpassing those of the various comparative examples. Specifically, all examples maintained stable and highly effective antibacterial activity, demonstrating that the different antibacterial agents exhibited potent effects under optimized formulations. In contrast, the antibacterial efficacy of the comparative examples decreased significantly when no antibacterial agent was added or when the ratio of key components was modified (e.g., reducing the amount of chitosan or increasing the amount of crosslinking agent).

[0077] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A chitosan-grafted cellulose-based antibacterial material, characterized in that: The invention is prepared from the following raw materials in parts by weight: 90-100 parts of cellulose matrix, 10-60 parts of chitosan, 2-20 parts of epoxy crosslinking agent, 300-350 parts of acidic solvent, 5-30 parts of alkaline neutralizer, 1-10 parts of plasticizer, and 15 parts of antibacterial agent. The antibacterial agent is a compound represented by Formula 1: Formula 1; R1 in the formula 1 is: cyano, ethyl, methyl, or propyl.

2. The chitosan-grafted cellulose-based antibacterial material according to claim 1, characterized in that: The cellulose matrix is ​​microcrystalline cellulose with a degree of polymerization of 150-375.

3. The chitosan-grafted cellulose-based antibacterial material according to claim 1, characterized in that: The epoxy crosslinking agent is 1,4-butanediol diglycidyl ether.

4. The chitosan-grafted cellulose-based antibacterial material according to claim 1, characterized in that: The deacetylation degree of the chitosan is ≥85%.

5. The chitosan-grafted cellulose-based antibacterial material according to claim 1, characterized in that: The acidic solvent is a 0.1 mol / L citric acid aqueous solution; The alkaline neutralizing agent is sodium bicarbonate.

6. The chitosan-grafted cellulose-based antibacterial material according to claim 1, characterized in that: The plasticizer is glycerol.

7. The chitosan-grafted cellulose-based antibacterial material according to claim 1, characterized in that: The antibacterial agent is any one of the compounds shown in the following structures: ； 。 8. A method for preparing a chitosan-grafted cellulose-based antibacterial material according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. The cellulose matrix is ​​added to the acidic solvent, heated to 40-80 ° C, stirred to dissolve, and the chitosan is added, and the mixture is stirred for 10-30 minutes to obtain a mixed material A; S2. The epoxy crosslinking agent is added to the mixture A, reacted at 40-80 ° C for 1-4 hours, the alkaline neutralizing agent is added, and the pH is adjusted to 7-8 to obtain a mixture B; S3. Add the plasticizer and antibacterial agent to the mixed material B, stir and mix for 10-20 minutes, pour into a mold, dry at 40-60°C for 6-12 hours, and demold to obtain the chitosan-grafted cellulose-based antibacterial material.

9. The method for preparing a chitosan-grafted cellulose-based antibacterial material according to claim 8, characterized in that: The reaction temperature in S2 is 50-70° C., and the reaction time is 2-3 hours.

10. Use of the chitosan-grafted cellulose-based antibacterial material according to any one of claims 1 to 7 in the preparation of antibacterial medical dressings, food packaging films and antibacterial substrates.

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