Musa peel-based antibacterial composite fiber and preparation method thereof

Abstract

The invention discloses a banana peel-based antibacterial composite fiber and a preparation method thereof, and relates to the technical field of high polymer materials. In the preparation method, an antibacterial nutrient substance Musarin and a fiber material Musarin cellulose are sequentially extracted from an agricultural waste banana peel, the fiber material Musarin is modified and embedded in the Musarin, and the Musarin, the fiber material Musarin and the fiber material Musarin are prepared into the water-soluble composite fiber through wet spinning with polyvinyl alcohol and polyvinylpyrrolidone. The banana peel-based antibacterial composite fiber is high in long-acting antibacterial property, good in water solubility, soft in hand feeling and good in mechanical strength, the banana peel is fully utilized in the manufacturing process of the banana peel-based antibacterial composite fiber, and the banana peel-based antibacterial composite fiber has the advantages of being green and environmentally friendly. The composite fiber has wide application potential in the fields of green textiles, antibacterial medical materials, degradable packaging materials and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a banana peel-based antibacterial composite fiber and a preparation method thereof. Background Art

[0002] Banana peel, as an agricultural waste, is rich in antibacterial substances and cellulose and is an ideal source of antibacterial fiber materials.

[0003] The antibacterial components in banana peels mainly include polyphenols, flavonoids, and tannins. In addition, there are nutrients such as tryptophan, vitamin B6, various trace elements, and serotonin. Banana peel extracts are often collectively referred to as "banana peelin", which has multiple effects such as antibacterial and antioxidant, stress relief, and improvement of cardiovascular health. However, active ingredients such as polyphenols, flavonoids, and serotonin are easily decomposed under warm light conditions and are difficult to preserve in fabrics. Some polymer compounds can encapsulate banana peelin, and banana peels contain a large amount of cellulose, which can form polymer fibers rich in hydrogen bonds, adsorbing and stabilizing molecules such as polyphenols. The existing technology still lacks a banana peel-based composite fiber that can slowly release banana peelin and has high mechanical strength. Summary of the Invention

[0004] The present invention aims to provide a banana peel-based antibacterial composite fiber and a preparation method thereof. Antibacterial banana peel extract and banana peel cellulose are extracted from banana peels in sequence, and the latter is modified to prepare a water-soluble composite fiber that can encapsulate and slowly release the former, thereby achieving high-value comprehensive utilization of banana peel waste.

[0005] An object of the present invention is to disclose a method for preparing a banana peel-based antibacterial composite fiber, comprising the following steps:

[0006] S1: fresh banana peels are washed and enzyme-inactivated, dried, crushed, and sieved to obtain banana peel powder. The banana peel powder is ultrasonically extracted in an extraction solvent, filtered to obtain banana peel residue and filtrate, and the filtrate is decolorized, purified, and concentrated to obtain banana peelin;

[0007] S2: washing and drying banana peel residue to obtain banana peel bran, soaking the banana peel bran in alkali solution, washing it, bleaching it in hydrogen peroxide solution, washing it to neutrality, and drying it to obtain banana peel cellulose;

[0008] S3: dissolving banana peel cellulose in a hot alkaline solution, adding a carboxyl modifier to modify the cellulose, neutralizing the cellulose, washing the cellulose, and drying the cellulose to obtain modified banana peel cellulose;

[0009] S4: Modified banana peel cellulose is dissolved in an ethanol-water solution, and an antibacterial drug including at least banana peelin is added while stirring until it is completely dissolved. Then, polyvinyl alcohol and polyvinyl pyrrolidone are added and mixed evenly to obtain a spinning solution. The spinning solution is formed into a fiber bundle through a spinneret, and after solidification, it is stretched and shaped, and then dried and rolled to obtain a banana peel-based antibacterial composite fiber.

[0010] Preferably, the enzyme inactivation is carried out by treating in pressurized steam at 105 - 120 °C for 30 - 60 s. Since banana peels contain enzymes such as polyphenol oxidase, which will destroy the active substances during the extraction process, enzyme inactivation treatment is required. Compared with scalding with boiling water, steam enzyme inactivation at a higher temperature for a shorter time causes less loss of active substances. In addition, (meta) bisulfite can also be used to soak and inactivate enzymes at a lower temperature, which can also achieve the effect of softening the cell wall, but it is easy to introduce new impurities.

[0011] Furthermore, the ultrasonic extraction is as follows: extracting at 50 - 60 °C under ultrasonic power of 100 - 400 W for 20 - 40 min; the extraction solvent is an ethanol aqueous solution with a volume fraction of 60 - 75% or an acetone aqueous solution with a volume fraction of 65 - 85%, and the material-liquid ratio of banana peel powder to the extraction solvent is 1:20 - 30 g / mL. Under the above ultrasonic extraction conditions, the cell wall can be first destroyed with a lower power, and then the power can be increased to strengthen diffusion, further reducing the heat loss of the active ingredients. The extraction solution with the above formula and dosage can effectively take into account both hydrophilic and lipophilic components and defat the banana peel powder.

[0012] Furthermore, the decolorization and purification is carried out by activated carbon decolorization and / or macroporous resin purification, including either separately performing any one of the two or first performing activated carbon decolorization and then macroporous resin purification. The activated carbon decolorization is specifically: adding 1 - 2 wt% of activated carbon to the extraction solution, stirring at 50 °C for about 30 min and then filtering, which can be repeated once. The macroporous resin purification is: loading onto non / weak polar macroporous resin, eluting the pigment with 30% ethanol, and then collecting musaflavin with 70% ethanol.

[0013] Furthermore, the alkali solution is a sodium hydroxide solution with a mass fraction of 2 - 5 wt%, and the material-liquid ratio of banana peel bran to the alkali solution is 1:9 - 20 g / mL; the bleaching agent is a hydrogen peroxide solution with a mass fraction of 2 - 4 wt%, and the material-liquid ratio of banana peel bran to the bleaching agent is 1:11 - 20 g / mL.

[0014] More preferably, the soaking temperature of banana peel bran in the alkali solution is 80 °C and the soaking time is 2 h; the soaking temperature of banana peel bran in the bleaching agent is 70 °C and the soaking time is 1 h.

[0015] The alkali solution treatment mainly removes lignin and hemicellulose in banana peel bran, while the bleaching agent can not only remove pigments but also oxidize some impurities. After each treatment, it is necessary to wash with water until neutral.

[0016] Furthermore, the hot alkali solution is a sodium hydroxide solution at 60 - 80 °C; the carboxylation modifier is selected from chloroacetic acid, vinyl chloride, methyl chloroacetic acid or chloropropionic acid, and the mass ratio of the carboxylation modifier to banana peel cellulose is 1 - 2:1.

[0017] Further preferably, the mass ratio of sodium hydroxide to banana peel cellulose in the hot alkali solution is 6:1, the mass ratio of the carboxylation modifier to banana peel cellulose is 1.5:1, the modification reaction time is 2 - 3 h, and the subsequent drying is carried out at 60 °C.

[0018] Further, in the spinning solution, the modified banana peel cellulose accounts for 5 - 10 wt%, polyvinyl alcohol (PVA) accounts for 6 - 10 wt%, polyvinylpyrrolidone (PVP) accounts for 0.5 - 2 wt%, the antibacterial drug accounts for 1 - 2 wt%, and the balance is an ethanol aqueous solution. In addition to musa sapientum Linn., the antibacterial drug may also include, but is not limited to, the following substances: silver nanoparticles, zinc oxide nanoparticles, benzalkonium chloride, zeolitic imidazolate framework material - 8 (ZIF - 8), polyhexamethylene biguanide (PHMB) and any combination of any of them.

[0019] Compared with the prior art in which the active substance is encapsulated by cellulose nanocrystals, the present invention uses modified (carboxymethyl) cellulose to embed the antibacterial drug, which has lower cost, easier drug loading, and more stable antibacterial effect. Although the sustained release is not uniform enough, it has pH and temperature - humidity dependence and is more suitable for the application environment of textiles, especially fabrics in contact with the human body.

[0020] Further preferably, in the ethanol aqueous solution, the mass ratio of ethanol to water is 1:2; the degree of polymerization of the polyvinyl alcohol is 2000 - 4000, and the degree of polymerization of the polyvinylpyrrolidone is 1600 - 3000.

[0021] The role of polyvinyl alcohol is to enhance water solubility, improve the flexibility and mechanical strength of the fiber; the role of polyvinylpyrrolidone is to improve the compatibility between different components, further stabilize the antibacterial drug, and improve the rheology of the spinning solution.

[0022] Preferably, the curing is carried out by soaking in a 5 - 10 wt% calcium chloride aqueous solution for 10 - ¾0 min and then washing with water. Alternatively, a coagulation bath of an acetone aqueous solution (acetone to water mass ratio of 8:2) can also be used for curing, but it may result in a large fiber porosity, slightly lower mechanical strength, uneven distribution of musa sapientum Linn., and poor antibacterial sustained - release effect.

[0023] Further, the diameter of the spinneret is 0.2 - 0.5 mm, the spinning rate of the spinneret is 0.5 - 5 m / min, the rates of stretching and shaping and winding are 1 - 10 m / min, and the drying temperature is 50 - 60 °C.

[0024] Another object of the present invention is to disclose a banana peel - based antibacterial composite fiber prepared by the above - mentioned preparation method of the banana peel - based antibacterial composite fiber.

[0025] The beneficial effects of the technical solution of the present invention are:

[0026] 1. The preparation method of the banana peel-based antibacterial composite fiber of the present invention makes comprehensive and full use of banana peels, using both the cellulose and antibacterial nutrients in them for the preparation of a composite fiber, and the composite fiber is water-soluble. Therefore, this technical solution has environmental protection and sustainability.

[0027] 2. In the preparation method of the present invention, antibacterial substances such as banana peel element are made into fibers after being fully mixed with modified banana peel cellulose, and are wrapped in the egg-box structure cross-linked network formed by cellulose and polyvinyl alcohol. Its loading rate is increased, the loss rate is reduced, and it has a temperature and humidity, pH-dependent sustained release effect in applications, which is suitable for manufacturing fabrics in contact with the human body. Specific Embodiments

[0028] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the technical solutions of the present invention will be further described below in conjunction with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and should be understood as an illustration of the technical solutions of the present invention rather than a limitation.

[0029] Example 1

[0030] Prepare a banana peel-based antibacterial composite fiber according to the following steps:

[0031] (1) After washing fresh banana peels, inactivate enzymes in pressurized steam at 110 °C for 60 s, then dry at 60 °C, crush and pass through an 80-mesh sieve to obtain 1 kg of banana peel powder. The obtained banana peel powder is soaked in 20 L of an ethanol solution with a volume fraction of 70%, and extracted under ultrasonic waves at 55 °C and a power of 300 W for 30 min. Filter to obtain banana peel residue and filtrate. The filtrate is adsorbed twice with 300 g of activated carbon at 50 °C for 30 min each. Filter out the activated carbon and concentrate and dry to obtain banana peel element.

[0032] (2) The obtained banana peel residue is washed with water and dried at 60 °C, and then passed through an 80-mesh sieve to obtain banana peel bran. Soak 920 g of banana peel bran in 10 L of a sodium hydroxide solution with a mass fraction of 3%, stir at 80 °C for 2 h, filter and wash with distilled water until neutral. Then soak the banana peel bran in 12 L of a hydrogen peroxide solution with a mass fraction of 4%, stir at 70 °C for 1 h, filter again and wash until neutral, and dry at 60 °C to obtain banana peel cellulose.

[0033] (3) Dissolve 900 g of banana peel cellulose in 22 L of a sodium hydroxide solution with a mass fraction of 25% at 70 °C, then add 1350 g of chloroacetic acid, keep the temperature and react for 3 h, then neutralize with dilute hydrochloric acid to neutral, filter and wash with distilled water to remove chloride ions, and dry at 60 °C to obtain modified banana peel cellulose.

[0034] (4) Take 500 g of modified banana peel cellulose, dissolve it in a solvent composed of 2750 g of ethanol and 5500 g of water, then add an antibacterial agent composed of 50 g of banana peel element and 50 g of ZIF-8 while stirring, and then add 1000 g of PVA-2000 and 150 g of PVP-2000 to obtain a spinning solution. The spinning solution is extruded through a spinneret with a diameter of 0.3 mm at a rate of 2 m / min, then enters a 5% calcium chloride solution for curing for 15 min, and then is stretched and shaped and dried at 60 °C, and finally wound at a rate of 5 m / min to obtain the banana peel-based antibacterial composite fiber.

[0035] Example 2

[0036] The only difference between this example and Example 1 is that the composition ratio of the spinning solution is: 600 g of modified banana peel cellulose, 8350 g of solvent (mass ratio of ethanol to water is 1:2), 150 g of antibacterial agent (100 g of banana peel element, 50 g of benzalkonium chloride), 800 g of PVA, and 100 g of PVP.

[0037] Example 3

[0038] The only difference between this example and Example 1 is that the obtained banana peel powder is soaked in 25 L of an acetone solution with a volume fraction of 80% and extracted under ultrasonic waves at 60 °C and a power of 200 W for 25 min.

[0039] Example 4

[0040] The only difference between this example and Example 1 is that the filtrate after ultrasonic extraction is adsorbed with 200 g of activated carbon at 50 °C for 30 min, the activated carbon is filtered off, and then it is added to AB-8 macroporous resin, the pigment is eluted with 30% ethanol, and then collected with 70% ethanol and concentrated and dried to obtain banana peel element.

[0041] Example 5

[0042] The only difference between this example and Example 1 is that the carboxylation modification temperature is 60 °C and the carboxylation modifier is 1500 g of chloroacetic acid methyl ester.

[0043] Example 6

[0044] The only difference between this example and Example 1 is that the coagulation bath used is replaced with an aqueous acetone solution with a mass fraction of 80%.

[0045] Comparative Example 1

[0046] The only difference between this comparative example and Example 1 is that carboxylation modification is not carried out, and directly the same amount of banana peel cellulose is used to replace the modified banana peel cellulose for fiber production.

[0047] The banana peel-based antibacterial composite fibers of Examples 1-6 and Comparative Example 1 were tested for mechanical strength, antibacterial property, and water solubility. Among them, the mechanical strength test was for the breaking strength (unit: cN), and the fiber fineness (unit: dtex) was measured for comparison. The antibacterial property test was carried out according to the oscillation method in the national standard GB 20944.3-2008-T, and the comprehensive sterilization rate (%) of the dry fibers and the fibers taken out after soaking in water for 24 h against Escherichia coli, Staphylococcus aureus, and Candida albicans was tested respectively. The water solubility test was to determine the mass percentage of the fibers dissolved in water within 24 h in warm water at 70 °C, that is, the water dissolution rate (%) = (weight before dissolution - remaining weight after dissolution) / weight before dissolution × 100%. The test results are shown in Table 1.

[0048] Table 1 Mechanical strength, antibacterial effect, and water solubility of the composite fibers

[0049]

[0050] According to the above test results, it can be seen that the banana peel-based antibacterial composite fibers prepared by the present invention have good mechanical strength and continuous antibacterial effect, are soft to the touch, have controllable water solubility, and have the characteristics of environmental protection.

[0051] Obviously, the above embodiments are only examples for clear illustration, rather than limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description, and the obvious changes or modifications derived therefrom should still be regarded as the protection scope of the present invention.

Claims

1. A preparation method of banana peel-based antibacterial composite fiber, characterized in that, It includes the following steps: S1: Wash and inactivate enzymes of fresh banana peels, dry them, crush and sieve to obtain banana peel powder. Ultrasonically extract the banana peel powder in an extraction solvent, filter to obtain banana peel residue and filtrate. After decolorizing and purifying the filtrate, concentrate it to obtain banana peel element; S2: Wash and dry the banana peel residue to obtain banana peel bran. Soak the banana peel bran in an alkali solution, wash it, then soak it in a bleaching agent, wash it until neutral and dry to obtain banana peel cellulose; S3: Dissolve the banana peel cellulose in a hot alkali solution, add a carboxylation modifier for modification, neutralize it, wash and dry to obtain modified banana peel cellulose; S4: Dissolve the modified banana peel cellulose in an ethanol aqueous solution, add an antibacterial drug including at least banana peel element while stirring until completely dissolved, then add polyvinyl alcohol and polyvinylpyrrolidone and mix evenly to obtain a spinning solution. The spinning solution forms a fiber bundle through a spinneret, is solidified and then stretched and shaped, dried and wound to obtain banana peel-based antibacterial composite fiber.

2. The preparation method of the banana peel-based antibacterial composite fiber according to claim 1, characterized in that, The enzyme inactivation is to treat in pressurized steam at 105 - 120 °C for 30 - 60 s.

3. The preparation method of the banana peel-based antibacterial composite fiber according to claim 1, characterized in that, The ultrasonic extraction is to extract at 50 - 60 °C under ultrasonic power of 100 - 400 W for 20 - 40 min. The extraction solvent is an ethanol aqueous solution with a volume fraction of 60 - 75% or an acetone aqueous solution with a volume fraction of 65 - 85%. The material-liquid ratio of banana peel powder to the extraction solvent is 1:20 - 30 g / mL.

4. The preparation method of the banana peel-based antibacterial composite fiber according to claim 1, characterized in that, The decolorizing and purifying is decolorization with activated carbon and / or purification with macroporous resin.

5. The preparation method of the banana peel-based antibacterial composite fiber according to claim 1, characterized in that, The alkali solution is a sodium hydroxide solution with a mass fraction of 2 - 5 wt%. The material-liquid ratio of banana peel bran to the alkali solution is 1:9 - 20 g / mL; the bleaching agent is a hydrogen peroxide solution with a mass fraction of 2 - 4 wt%. The material-liquid ratio of banana peel bran to the bleaching agent is 1:11 - 20 g / mL.

6. The preparation method of the banana peel-based antibacterial composite fiber according to claim 5, characterized in that, The soaking temperature of banana peel bran in the alkali solution is 80 °C and the soaking time is 2 h; the soaking temperature of banana peel bran in the bleaching agent is 70 °C and the soaking time is 1 h.

7. The preparation method of the banana peel-based antibacterial composite fiber according to claim 1, characterized in that, The hot alkali solution is a sodium hydroxide solution at 60 - 80 °C; the carboxylation modifier is selected from chloroacetic acid, vinyl chloride, methyl chloroacetic acid or chloropropionic acid. The mass ratio of the carboxylation modifier to banana peel cellulose is 1 - 2:

1.

8. The preparation method of the banana peel-based antibacterial composite fiber according to claim 1, characterized in that, In the spinning solution, the modified banana peel cellulose accounts for 5 - 10 wt%, polyvinyl alcohol accounts for 6 - 10 wt%, polyvinylpyrrolidone accounts for 0.5 - 2 wt%, the antibacterial drug accounts for 1 - 2 wt%, and the balance is ethanol aqueous solution.

9. The preparation method of the banana peel-based antibacterial composite fiber according to claim 1, characterized in that, The solidification is to soak in a calcium chloride aqueous solution with a mass fraction of 5 - 10 wt% for 10 - 30 min, and then wash with water.

10. A banana peel-based antibacterial composite fiber, characterized in that, It is prepared by the preparation method of the banana peel-based antibacterial composite fiber according to any one of claims 1 - 9.

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