Banana fiber-based membrane cloth and preparation method thereof

Abstract

The invention discloses a banana fiber-based membrane cloth and a preparation method thereof, and relates to the field of banana fibers.The preparation method comprises the steps of selecting banana fibers, conducting preliminary extraction through mechanical extrusion equipment, conducting degumming treatment and fine purification on the banana fibers subjected to preliminary extraction, and conducting drying and screening on the banana fibers subjected to degumming treatment and fine purification; and carrying out freeze drying and storage. Through multi-step optimization processes such as ultrasonic cleaning, pH buffer treatment, supramolecular self-assembly modification, spin coating, heat treatment crosslinking and the like, the mechanical strength, the water resistance and the functional performance of the banana fiber membrane cloth are remarkably improved. Particularly, a multifunctional coating is constructed by adopting a layer-by-layer self-assembly technology, so that the membrane cloth can be endowed with antibacterial property, waterproofness or conductivity according to different application requirements, and the application of the membrane cloth in the fields of medical protection, flexible electronics, intelligent spinning, high-performance filtering materials and the like is effectively expanded.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of banana fiber, in particular to a film cloth based on banana fiber and a preparation method thereof. BACKGROUND

[0002] With the increasing demand for environmental protection and sustainable development, natural fiber film cloth materials have a wide application prospect in medical protection, intelligent textiles, filtration materials and flexible electronics due to their biodegradability, air permeability and ecological and environmental protection characteristics. Banana fiber, as a natural polymer fiber material, has good mechanical strength, low density and abundant reserves, and is an ideal choice to replace traditional synthetic fiber materials. However, due to the limitations of the surface chemical properties and structural stability of the fiber, the current banana fiber film cloth is still difficult to meet the high-performance application requirements. Therefore, improving the mechanical properties, water resistance and functionalization ability of the banana fiber film cloth has become a key direction of current research.

[0003] Although the existing technology has modified the natural fiber, there are still two main defects: first, the water resistance is insufficient, and the structure is prone to degradation in a humid environment. The existing banana fiber film cloth is prone to swelling, strength reduction and even fiber decomposition in a high-humidity or water immersion environment, which limits its application in a high-humidity environment, such as medical dressings or functional protective materials. Second, the functional modification ability is limited, which is difficult to meet the specific application requirements. The existing banana fiber film cloth mostly uses a single physical or chemical modification method, which is difficult to build a stable functional layer, such as an antibacterial, waterproof or conductive layer, resulting in the limitation of the application of the film cloth in the fields of flexible electronics, filtration materials and intelligent textiles. SUMMARY

[0004] The present application aims to overcome the shortcomings of the prior art and provide a film cloth based on banana fiber and a preparation method thereof. Through ultrasonic cleaning, pH buffer treatment, supramolecular modification, spin coating and heat treatment cross-linking, the water resistance and functionality of the film cloth are improved. Specifically, the present application uses a supramolecular network structure to build a hydrogen bond strengthening layer on the surface of the banana fiber, which improves the hydrolysis resistance of the fiber and greatly improves the stability of the film cloth in a high-humidity environment. At the same time, a multi-functional coating layer is constructed by using layer-by-layer self-assembly technology, which can endow the film cloth with antibacterial, waterproof or conductive properties according to the requirements, so that it can be applied to various high-performance application scenarios such as medical protection, flexible electronics and intelligent textiles. Compared with the prior art, the banana fiber film cloth of the present application has high mechanical strength, excellent water resistance and customizable functional properties, which widens the application space of natural fiber film cloth in high-end fields.

[0005] Therefore, the present application provides a film cloth based on banana fiber and a preparation method thereof, which comprises the following steps:

[0006] The banana fibers are selected, and preliminary extraction is performed by a mechanical extrusion device. Degumming treatment and fine purification are performed based on the banana fibers after preliminary extraction. Drying and screening are performed based on the banana fibers after degumming treatment and fine purification, and freeze-drying and storage are performed.

[0007] Freeze-drying and storage are performed on the banana fibers after the freeze-drying and storage. Ultrasonic cleaning is performed on the banana fibers after the ultrasonic cleaning. pH buffer solution treatment is performed on the banana fibers after the pH buffer solution treatment. Freeze-drying is performed on the banana fibers after the freeze-drying.

[0008] Freeze-drying is performed on the banana fibers after the freeze-drying. Supramolecular host material selection is performed on the banana fibers after the supramolecular host material selection. Solvent system preparation is performed after the solvent system preparation. Catalyst addition is performed after the catalyst addition. Solution uniform mixing is performed after the solution uniform mixing.

[0009] The banana fibers are soaked and adsorbed by the supramolecular modification liquid. The banana fibers are spin-coated after the soaking and adsorption. The banana fibers are heat-treated and cross-linked after the spin-coating.

[0010] The banana fibers are heat-treated and cross-linked after the heat treatment and cross-linking. The banana fibers are constructed into a reinforcing layer after the reinforcing layer construction. The banana fibers are constructed into a flexible layer after the flexible layer construction, and a membrane cloth is obtained. The banana fibers are constructed into a functional layer after the flexible layer construction.

[0011] The membrane cloth is subjected to vacuum annealing treatment. The membrane cloth is subjected to argon plasma treatment after the vacuum annealing treatment. The membrane cloth is subjected to durability testing after the argon plasma treatment.

[0012] The composite material is prepared after the durability testing. The composite material is prepared after the forming process, and a finished product membrane cloth is obtained. The finished product membrane cloth is subjected to high-temperature hot pressing. The finished product membrane cloth is subjected to cutting and packaging after the high-temperature hot pressing.

[0013] In some embodiments, banana fiber raw materials are selected, and preliminary extraction is performed by a mechanical extrusion device. Degumming treatment and fine purification are performed based on the banana fibers after preliminary extraction. Drying and screening are performed based on the banana fibers after degumming treatment and fine purification, and freeze-drying and storage are performed, which specifically includes:

[0014] The banana fiber raw materials are selected.

[0015] Banana trees of 6-12 months old are selected, and the banana tree pseudostems are harvested. The outer cuticle and rough tissue of the banana tree pseudostems are stripped, and the banana tree pseudostems are cut longitudinally into strips of 2-4 cm wide.

[0016] Preliminary extraction is performed on the selected banana fiber raw materials by a mechanical extrusion device.

[0017] The non-fiber components are removed by mechanical extrusion equipment under a pressure of 5-10 MPa.

[0018] The banana fibers extracted by the mechanical extrusion equipment are immediately immersed in warm water at 40°C and stirred for cleaning, and the precipitated fiber materials are collected.

[0019] The stirring and cleaning process is repeated 3 times until the visible impurities on the surface of the fibers are basically removed.

[0020] The banana fibers after preliminary extraction are subjected to degumming treatment.

[0021] After stirring and cleaning, the banana fibers are subjected to alkali treatment using a sodium hydroxide solution. The lignin and hemicellulose structures in the banana fibers are destroyed by the sodium hydroxide solution. The fibers are immersed in a 3% (w / v) NaOH solution and maintained at a temperature of 60°C for 3 hours, with a stirring rate of 200 rpm during the process.

[0022] After the soaking is completed, deionized water is used to remove the residual alkali solution, and the washing is continued until the pH value of the washing liquid approaches 7.

[0023] The banana fibers after degumming treatment are subjected to fine purification.

[0024] The banana fibers are immersed in dilute hydrochloric acid for 1 hour to remove metal ions and other inorganic impurities in the fibers, and then washed 5 times with deionized water.

[0025] The banana fibers after fine purification treatment are subjected to drying and screening.

[0026] After the banana fibers are dispersed by a mechanical carding device, they are screened through a 100-mesh screen to retain fibers with a length of 5-15 mm and a diameter of 10-50 μm.

[0027] The banana fibers after drying and screening are subjected to freeze-drying and storage.

[0028] The banana fibers are subjected to freeze-drying at -50°C to remove deep-seated trace amounts of residual moisture. The freeze-drying time is 12 hours.

[0029] The freeze-dried banana fibers are stored in a sealed vacuum bag and placed in a drying cabinet for storage. The temperature and humidity of the drying cabinet are set to 25°C and 10% humidity.

[0030] In some embodiments, the banana fibers after freeze-drying and storage are subjected to ultrasonic cleaning, the banana fibers after ultrasonic cleaning are subjected to pH buffer solution treatment, and the banana fibers after pH buffer solution treatment are subjected to freeze-drying, which specifically includes:

[0031] The banana fibers after freeze-drying and storage are subjected to ultrasonic cleaning.

[0032] The banana fibers after ultrasonic cleaning are treated with a pH buffer solution.

[0033] An acetic acid-sodium acetate solution with a pH of 4-5 is prepared.

[0034] The banana fibers after ultrasonic cleaning are placed in the buffer solution at a ratio of fiber mass to solution volume of 1g:50mL, with a stirring rate of 150rpm, a room temperature of 25°C, and a soaking time of 30 minutes.

[0035] The buffer solution is removed by filtering through a 200-mesh stainless steel screen, and the filter is rinsed twice with deionized water. The pH value is detected by taking 1mL of the filtrate and using acid-base titration.

[0036] The banana fibers after pH buffer solution treatment are freeze-dried.

[0037] In some embodiments, based on the banana fibers after freeze-drying, a supramolecular host material is selected, based on the supramolecular host material selection, a solvent system is prepared, based on the solvent system preparation, a catalyst is added, and based on the catalyst addition, the solution is uniformly mixed, which specifically includes:

[0038] Based on the banana fibers after freeze-drying, a supramolecular host material is selected.

[0039] According to the hydrophilicity and adsorption characteristics of banana fibers, polydopamine, cucurbituril, amide hydrogen bond donor, and imidazole salt are used as host materials.

[0040] Based on the supramolecular host material selection, a solvent system is prepared.

[0041] Dimethyl sulfoxide is used as a polar solvent, and ethanol-water mixed solvent is used to reduce the surface tension of the solvent.

[0042] DMSO single solvent system is used for high-solubility supramolecules, and ethanol-water mixed solvent system is used for supramolecules that consider both water solubility and solvent dispersibility.

[0043] A magnetic stirrer is used to stir the solvent system preparation, with a temperature setting of 50°C, a stirring rate of 400rpm, and a stirring time of 15 minutes.

[0044] Based on the solvent system preparation, a catalyst is added.

[0045] Sodium p-hydroxybenzenesulfonate is used as a water-soluble catalyst, and a magnetic stirrer is used for stirring, with a stirring rate of 600rpm, a temperature of 45°C, a stirring time of 10 minutes, and a 200-mesh stainless steel screen is used for filtering to remove undissolved catalyst particles.

[0046] Based on the catalyst after the solution is uniformly mixed.

[0047] The supermolecular material is gradually added into the preheated solvent system, 10% material is added every 5 minutes, 600 rpm magnetic stirring is adopted for 60 minutes, and the temperature is maintained at 50℃±2℃ during stirring.

[0048] The ultrasonic disperser is used for ultrasonic treatment for 20 minutes, the frequency is set to 40 kHz, and the power is set to 200 W.

[0049] After stirring is completed, the solution is cooled to 25℃, and the transmittance of the supermolecular solution is detected by using ultraviolet-visible spectroscopy.

[0050] If the transmittance of the solution is greater than 90%, the solution is uniform and stable, otherwise the ultrasonic treatment time needs to be increased or the solution concentration needs to be reduced, and the supermolecular modified liquid is obtained.

[0051] In some specific embodiments, the banana fibers are soaked and adsorbed based on the supermolecular modified liquid, the banana fibers after soaking and adsorption are spin-coated, and the banana fibers after spin-coating are heat-treated and cross-linked, and the specific process comprises the following steps.

[0052] The banana fibers are soaked and adsorbed based on the supermolecular modified liquid.

[0053] The banana fibers after soaking and adsorption are spin-coated.

[0054] The spin-coating technology is used to uniformly deposit the supermolecular modifier on the surface of the fibers, the spin-coating machine is set to a rotation speed of 500 rpm, a coating time of 5 minutes, and a rotation acceleration of 300 rpm / s, the soaked fibers are placed into the spin-coating machine, and the multi-layer supermolecular modified coating is formed through the way of layer-by-layer coating, 5 minutes of standing after each coating, drying of the previous layer of coating film, and then the next step of coating, and the process is repeated for 3 rounds of spin-coating.

[0055] Low-temperature drying is used during coating, which is set to 40℃ for 30 minutes.

[0056] The banana fibers after spin-coating are heat-treated and cross-linked.

[0057] Through heat treatment, the supermolecular modified layer and the fiber surface form stable chemical bonding, and the heat treatment parameters are set as follows: the temperature range is set to 60-80℃, and the time is maintained for 2 hours.

[0058] Through heat treatment, the rearrangement of intermolecular hydrogen bonds is promoted, the poly cyclodextrin supermolecular host is more tightly packed on the active sites on the surface of the banana fibers during heating, and the molecular chains are rearranged under the action of temperature.

[0059] The fibers after heat treatment are slowly cooled to room temperature 25℃.

[0060] In some embodiments, the enhanced layer is constructed based on the heat-treated cross-linked banana fibers, the flexible layer is constructed based on the banana fibers after the enhanced layer construction, and the functional layer is constructed based on the banana fibers after the flexible layer construction, specifically including:

[0061] The enhanced layer is constructed based on the heat-treated cross-linked banana fibers.

[0062] The supermolecular network rich in hydrogen bond donors is introduced on the surface of the banana fibers, and the supermolecular network includes poly cyclodextrin and urea, the poly cyclodextrin provides host-guest interaction, and the urea serves as a hydrogen bond donor.

[0063] The rotation-coated banana fibers are taken, and the ratio of fiber mass to solution volume is 1 g:100 mL, the fibers are placed in the enhanced layer coating solution, the magnetic stirring rate is 200 rpm, the temperature is 30°C, the soaking time is 30 minutes, a rotation coating machine is used, the rotation speed is set to 400 rpm, the coating time is 5 minutes, a uniform enhanced layer is formed, the rotation acceleration is set to 200 rpm / s, and vacuum drying is performed at 45°C for 30 minutes.

[0064] The flexible layer is constructed based on the banana fibers after the enhanced layer construction, and a membrane cloth is obtained.

[0065] The tear resistance and ductility of the membrane cloth are improved by introducing the flexible layer, and the flexible layer includes PVA and graphene, the PVA provides flexibility, and the graphene endows enhanced thermal conductivity.

[0066] The functional layer is constructed based on the banana fibers after the flexible layer construction.

[0067] The functional layer includes antibacterial function, waterproof function, and conductive function.

[0068] The antibacterial function is achieved by using nano-silver, the waterproof function is achieved by using siloxane, and the conductive function is achieved by using MXene, an air flow spraying device is used, the spraying rate is controlled to 2 mL / min, the rotation speed is set to 600 rpm, the coating time is 5 minutes, and vacuum drying is performed at 50°C for 40 minutes.

[0069] In some embodiments, the obtained membrane cloth is subjected to vacuum annealing treatment, the membrane cloth after the vacuum annealing treatment is subjected to argon plasma treatment, and the membrane cloth after the argon plasma treatment is subjected to durability testing, specifically including:

[0070] The vacuum annealing treatment is performed on the obtained membrane cloth.

[0071] The argon plasma treatment is performed on the membrane cloth after the vacuum annealing treatment.

[0072] The radio frequency argon plasma treatment device was set to a power of 50 W, a treatment time of 5 minutes, and an argon gas flow of 50 sccm.

[0073] After the argon plasma treatment was completed, the film cloth was placed in a dust-free environment for 30 minutes, and the dust-free environment was set to a temperature of 25°C and a humidity of 30%.

[0074] The film cloth after argon plasma treatment was subjected to durability testing.

[0075] Four buffer solutions of pH 3, pH 5, pH 7, and pH 9 were used for immersion testing. 10 mg of film cloth sample was placed in 50 mL of buffer solution, and the temperature was set to 25°C for 24 hours.

[0076] The film cloth coating stability was detected by ultraviolet-visible light spectroscopy, and the film cloth dissolution rate was calculated, specifically:

[0077]

[0078] In the formula, D is the dissolution rate of the film cloth, which is used to measure the degree of mass loss of the film cloth in different pH environments, m_0 is the initial sample mass (mg), indicating the mass of the film cloth at the beginning of the experiment, and m_t is the sample mass after 24 hours of immersion (mg), indicating the remaining mass of the film cloth after immersion in the solution, is the percentage of film cloth mass loss, reflecting the chemical stability of the film cloth.

[0079] When D≤5%, it indicates that the film cloth has good chemical resistance, and when D>5%, the degree of supramolecular crosslinking needs to be optimized.

[0080] An electronic universal testing machine was used to test the tensile strength, with a tensile rate of 10 mm / min. The film cloth sample size was 5 cm x 1 cm, and three repeated tests were performed. The calculation is as follows:

[0081]

[0082] In the formula, σ is the tensile strength MPa, indicating the tensile capacity of the film cloth under external force, F is the maximum tensile force (N) that the film cloth can withstand during the test, and A is the cross-sectional area (mm 2 ) of the sample, and the calculation method is:

[0083] A = w x t

[0084] In the formula, w is the width of the sample in mm, and t is the thickness of the sample in mm, is the maximum tensile stress per unit area, which measures the tensile strength of the film cloth.

[0085] When σ≥50MPa: excellent mechanical properties, when σ30-50MPa: good mechanical properties, and when σ<30MPa: the reinforcing layer of the membrane cloth needs to be optimized.

[0086] In some embodiments, the composite material is prepared after the durability test, the forming process is performed after the preparation of the composite material, the finished membrane cloth is obtained, the high-temperature hot pressing is performed based on the obtained finished membrane cloth, and the cutting and packaging are performed based on the finished membrane cloth after the high-temperature hot pressing, specifically including:

[0087] The composite material is prepared after the durability test.

[0088] The forming process is performed after the preparation of the composite material, and the finished membrane cloth is obtained.

[0089] The PLA / PHB composite solution is used, the viscosity is controlled to be 1000-5000 cP, the wet spinning equipment is used, the solution is extruded, a 30°C ethanol-water coagulation bath 1:1, v / v is used, the spinning speed is set to be 5-10 m / min, the wet spinning is performed, and the vacuum drying at 50°C is performed for 6 hours.

[0090] The PLA / PHB composite solution concentration 5%-10% w / v is used, the electrospinning machine is used, the voltage is set to be 15-25 kV, the jet speed is 0.5 mL / h, and the electrospinning is performed by vacuum drying at 60°C for 8 hours.

[0091] The high-temperature hot pressing is performed based on the obtained finished membrane cloth, the membrane cloth formed by the wet spinning and the electrospinning is placed in a stainless steel mold, the surface of the stainless steel mold is sprayed with a release agent, the high-temperature hot pressing at 120-150°C is performed for 10 minutes, the pressure of 5-10 MPa is applied, the uniformity of the membrane cloth is improved, and after the heating is completed, the slow cooling is performed at a cooling rate of 5°C / min.

[0092] The cutting and packaging are performed based on the finished membrane cloth after the high-temperature hot pressing.

[0093] The laser cutting machine is used to cut the membrane cloth according to the specifications, and the high-precision stamping die is used to mass-produce the finished membrane cloth with consistent size.

[0094] In summary, the application provides a banana fiber-based membrane cloth and a preparation method thereof. Through multiple optimization processes such as ultrasonic cleaning, pH buffer treatment, supramolecular self-assembly modification, spin coating, and heat treatment crosslinking, the mechanical strength, water resistance, and functional properties of the banana fiber membrane cloth are significantly improved. In particular, the layer-by-layer self-assembly (LBL) technique is used to construct a multifunctional coating, which can impart antibacterial, waterproof, or conductive properties to the membrane cloth according to different application requirements, effectively expanding its applications in medical protection, flexible electronics, intelligent textiles, and high-performance filtration materials. Compared with the prior art, the membrane cloth of the application not only has excellent mechanical properties, air permeability, and durability, but also remains stable in complex environments, providing a new technical solution for the high-end application of natural fiber membrane materials. BRIEF DESCRIPTION OF DRAWINGS

[0095] Figure 1 is the overall flowchart of a banana fiber-based membrane cloth and a preparation method thereof provided by the embodiments of the application. DETAILED DESCRIPTION

[0096] Please refer to Figure 1 which shows the flowchart of one embodiment of a banana fiber-based membrane cloth and a preparation method thereof according to the present disclosure

[0097] As Figure 1 shown, a banana fiber-based membrane cloth and a preparation method thereof include the following steps:

[0098] Banana fibers are selected and subjected to preliminary extraction by mechanical extrusion equipment. The banana fibers after preliminary extraction are subjected to degumming treatment and fine purification. The banana fibers after degumming treatment and fine purification are subjected to drying and screening, and cold freeze drying and storage.

[0099] The banana fibers after cold freeze drying and storage are subjected to ultrasonic cleaning. The banana fibers after ultrasonic cleaning are subjected to pH buffer solution treatment. The banana fibers after pH buffer solution treatment are subjected to cold freeze drying.

[0100] The banana fibers after cold freeze drying are subjected to supramolecular host material selection. After the supramolecular host material selection, a solvent system is prepared. After the solvent system is prepared, a catalyst is added. After the catalyst is added, the solution is uniformly mixed.

[0101] The banana fibers are soaked and adsorbed by the supramolecular modification liquid. The banana fibers after soaking and adsorption are subjected to spin coating. The banana fibers after spin coating are subjected to heat treatment crosslinking.

[0102] Based on the crosslinking of the banana fibers after heat treatment, the reinforcing layer is constructed, and based on the reinforcing layer construction, the banana fibers are constructed into a flexible layer, and the membrane cloth is obtained, and based on the flexible layer construction, the banana fibers are constructed into a functional layer.

[0103] Based on the obtained membrane cloth, vacuum annealing treatment is carried out, and based on the vacuum annealing treatment, argon plasma treatment is carried out, and based on the argon plasma treatment, durability test is carried out.

[0104] Based on the durability test, composite material preparation is carried out, and based on the composite material preparation, forming process is carried out, and the finished product membrane cloth is obtained, and based on the obtained finished product membrane cloth, high temperature hot pressing is carried out, and based on the high temperature hot pressing, cutting and packaging are carried out.

[0105] In some embodiments, banana fiber raw materials are selected, and preliminary extraction is carried out by mechanical extrusion equipment, and based on the preliminary extraction of banana fibers, degumming treatment and fine purification are carried out, and based on the degumming treatment and fine purification of banana fibers, drying and screening are carried out, and cold drying and storage are carried out, which specifically includes:

[0106] Banana fiber raw materials are selected.

[0107] Banana trees of 6-12 months old are selected, and the banana tree pseudostems are harvested, and the outer cuticle and rough tissue of the banana tree pseudostems are removed, and the banana tree pseudostems are cut longitudinally into 2-4 cm wide strips.

[0108] Based on the selection of banana fiber raw materials, preliminary extraction is carried out by mechanical extrusion equipment.

[0109] Mechanical extrusion equipment is used to preliminarily remove non-fiber components under a pressure of 5-10 MPa;

[0110] The banana fibers extracted by the mechanical extrusion equipment are immediately soaked in 40℃ warm water and stirred and washed, and the precipitated fiber materials are collected.

[0111] The stirring rate is 300 rpm, and the stirring time is 30 minutes, and after the stirring is completed, 100 mesh stainless steel screen is used for filtration, and the precipitated fiber materials are collected.

[0112] The stirring and washing process is repeated 3 times until the visible impurities on the surface of the fibers are basically removed.

[0113] Degumming treatment is carried out based on the preliminary extraction of banana fibers.

[0114] After stirring and washing, sodium hydroxide solution is used for alkali treatment of banana fibers, and the lignin and hemicellulose structure in the banana fibers are destroyed by sodium hydroxide solution, and the fibers are soaked in 3% (w / v) NaOH solution, and the temperature is maintained at 60℃, and the time is 3 hours, and the stirring rate is 200 rpm during the period.

[0115] After soaking, residual lye is removed using deionized water, and the fibers are washed until the pH of the wash water is close to 7.

[0116] The residual hemicellulose is further removed using hydrogen peroxide bleaching. The alkali treated banana fibers are soaked in 5% (w / v) H2O2 solution for 2 hours at 50°C, and rinsed thoroughly with deionized water until no chemical residue is present on the surface of the fibers.

[0117] The degummed banana fibers are subjected to fine purification.

[0118] The banana fibers are soaked in dilute hydrochloric acid for 1 hour to remove metal ions and other inorganic impurities from the fibers, and rinsed 5 times with deionized water.

[0119] An ethanol / water mixture is used to remove lipids and residual oils from the banana fibers by soaking in a 1:1 mixture at room temperature (25°) for 30 minutes using an ultrasonic frequency of 40 kHz.

[0120] The fine purified banana fibers are dried and sieved.

[0121] The fine purified banana fibers are subjected to low temperature drying in a vacuum drying oven at 60°C for 6 hours, and the dried fibers are dispersed using a mechanical carding device with a carding roller speed of 300 rpm.

[0122] The banana fibers are dispersed using a mechanical carding device, and sieved through a 100 mesh screen to retain fibers having a length of 5-15 mm and a diameter of 10-50 μm.

[0123] The dried and sieved banana fibers are subjected to freeze drying and storage.

[0124] The banana fibers are subjected to freeze drying at -50°C for 12 hours to remove deep-seated trace amounts of residual moisture.

[0125] The freeze-dried banana fibers are stored in a sealed vacuum bag and placed in a desiccator for storage, with the temperature and humidity of the desiccator set to 25°C and 10% humidity.

[0126] In some embodiments, the freeze-dried and stored banana fibers are subjected to ultrasonic cleaning, the ultrasonically cleaned banana fibers are subjected to pH buffer solution treatment, and the pH buffer solution treated banana fibers are subjected to freeze drying, which specifically includes:

[0127] The freeze-dried and stored banana fibers are subjected to ultrasonic cleaning.

[0128] An ultrasonic cleaning solution was prepared by mixing ethanol and deionized water at a volume ratio of 1:1. The dried and screened banana fibers were placed in the cleaning solution at a ratio of fiber mass to solution volume of 1 g:100 mL.

[0129] The ultrasonic cleaner was set to a frequency of 40 kHz and a power of 200 W for cleaning, with a temperature setting of 30°C and an ultrasonic cleaning time of 30 minutes.

[0130] After cleaning, the solution was filtered using a 200-mesh stainless steel screen, and the fibers were rinsed twice with deionized water. The cleaned banana fibers were then dried at 120°C for 1 hour, and the mass change was measured.

[0131] The banana fibers after ultrasonic cleaning were treated with a pH buffer solution.

[0132] An acetic acid-sodium acetate buffer solution with a pH of 4-5 was prepared as follows:

[0133]

[0134] wherein pH is the acidity or alkalinity value of the solution, pKa is the negative logarithmic value of the acidity constant (Ka) of acetic acid, pKa = 4.76, [A - ] is the concentration of sodium acetate (CH3COONa) for adjusting the alkalinity of the solution, and [HA] is the concentration of acetic acid (CH3COOH) for adjusting the acidity of the solution. is the logarithmic value of the relative concentration ratio between acetic acid and sodium acetate, used to calculate the pH value of the final solution.

[0135] The banana fibers after ultrasonic cleaning were placed in the buffer solution at a ratio of fiber mass to solution volume of 1 g:50 mL, with a stirring rate of 150 rpm and a room temperature of 25°C, and soaked for 30 minutes.

[0136] The buffer solution was filtered using a 200-mesh stainless steel screen, and the fibers were rinsed twice with deionized water. The pH value of 1 mL of the filtrate was detected by acid-base titration.

[0137] The banana fibers after pH buffer solution treatment were freeze-dried.

[0138] The soaked banana fibers were cooled to -80°C for 30 minutes using liquid nitrogen pre-cooling for pre-freezing treatment.

[0139] The pre-frozen fibers were placed in a freeze dryer, and the temperature was set to -50°C, the vacuum degree was set to 0.1 Pa, and the freeze-drying time was set to 12 hours.

[0140] Take 10 mg of banana fiber, dry at 120°C for 1 hour, and calculate the mass change before and after freeze-drying to obtain the water content.

[0141] In some embodiments, based on the freeze-dried banana fiber, the selection of the supramolecular host material is carried out, based on the selection of the supramolecular host material, the preparation of the solvent system is carried out, based on the preparation of the solvent system, the addition of the catalyst is carried out, based on the addition of the catalyst, the uniform mixing of the solution is carried out, which specifically includes:

[0142] Based on the freeze-dried banana fiber, the selection of the supramolecular host material is carried out.

[0143] According to the hydrophilicity and adsorption characteristics of banana fiber, poly cyclodextrin, cucurbituril, amide hydrogen bond donor and imidazole salt are used as host materials.

[0144] Poly cyclodextrin provides host-guest interaction to form intramolecular inclusion structure, cucurbituril as a strong hydrogen bond donor improves the chemical stability and adsorption capacity of the fiber, amide hydrogen bond donor enhances the mechanical strength of the supramolecular network and improves the tear resistance of the fiber, and imidazole salt imparts certain electrical conductivity to the film cloth, which can be used for flexible electronic materials.

[0145] Based on the selection of the supramolecular host material, the preparation of the solvent system is carried out.

[0146] Dimethyl sulfoxide is used as a polar solvent, and ethanol-water mixed solvent is used to reduce the surface tension of the solvent.

[0147] DMSO single solvent system is used for high solubility supramolecular, and ethanol-water mixed solvent system is used for supramolecular with both water solubility and solvent dispersibility.

[0148] A magnetic stirrer is used for stirring the preparation of the solvent system, the temperature is set to 50°C, the stirring rate is 400 rpm, and the time is 15 minutes.

[0149] Based on the preparation of the solvent system, the addition of the catalyst is carried out.

[0150] Sodium p-hydroxybenzenesulfonate is used as a water-soluble catalyst, and a magnetic stirrer is used for stirring, the stirring rate is 600 rpm, the temperature is 45°C, the time is 10 minutes, a 200-mesh stainless steel screen is used for filtration to remove undissolved catalyst particles.

[0151] Based on the addition of the catalyst, the uniform mixing of the solution is carried out.

[0152] The supramolecular material is gradually added to the preheated solvent system, 10% material is added every 5 minutes, 600 rpm magnetic stirring is carried out for 60 minutes, and the temperature is maintained at 50°C ± 2°C during the stirring process.

[0153] The ultrasonic disperser is used for 20 minutes of ultrasonic treatment at a frequency of 40 kHz and 200 W.

[0154] After stirring, the solution is cooled to 25°C, left to stand for 12 hours, and the transmittance of the supramolecular solution is detected by ultraviolet-visible spectroscopy.

[0155] If the transmittance of the solution is greater than 90%, the solution is uniform and stable, otherwise the ultrasonic treatment time needs to be increased or the solution concentration needs to be reduced to obtain the supramolecular modified solution.

[0156] In some specific embodiments, the banana fibers are soaked and adsorbed based on the supramolecular modified solution, the banana fibers after soaking and adsorption are spin-coated, and the banana fibers after spin-coating are heat-treated and cross-linked, which specifically comprises:

[0157] The banana fibers are soaked and adsorbed based on the supramolecular modified solution.

[0158] The frozen and dried banana fibers are placed in the supramolecular modified solution at a ratio of fiber mass:solution volume = 1 g:100 mL.

[0159] The magnetic stirrer is used for stirring at a stirring rate of 300 rpm, and the temperature is maintained at 25°C±2°C, and the solution is left to stand for 12 hours.

[0160] After soaking, the solution is filtered with a 200-mesh stainless steel screen to remove excess modified solution, and then washed with deionized water for 3 times to remove unbound free supramolecular materials.

[0161] The banana fibers after soaking and adsorption are spin-coated.

[0162] The supramolecular modifier is uniformly deposited on the surface of the fibers by using the spin-coating technology. The spin-coater is used at a rotating speed of 500 rpm, a coating time of 5 minutes, and a rotating acceleration of 300 rpm / s. The soaked fibers are placed in the spin-coater, and the supramolecular modifier is coated layer by layer. After each coating, the fibers are left to stand for 5 minutes, and then the next coating is performed after the previous layer is dried. The above process is repeated for 3 times to form a multi-layer supramolecular modified coating.

[0163] Low-temperature drying is used during the coating process at a temperature of 40°C for 30 minutes.

[0164] The banana fibers after spin-coating are heat-treated and cross-linked.

[0165] The supramolecular modified layer is chemically bonded to the surface of the fibers by heat treatment. The heat treatment parameters are set as follows: the temperature range is 60-80°C, and the time is maintained for 2 hours.

[0166] The rearrangement of intermolecular hydrogen bonds is promoted by heat treatment. During heating, the polydextrin supramolecular host more tightly encapsulates the active sites on the surface of the banana fiber. Under the action of temperature, the molecular chain segments rearrange.

[0167] The fiber after heat treatment is slowly cooled to room temperature 25℃.

[0168] In some embodiments, the banana fiber after heat treatment and cross-linking is used to construct the reinforcing layer, the banana fiber after the construction of the reinforcing layer is used to construct the flexible layer, and the banana fiber after the construction of the flexible layer is used to construct the functional layer, which specifically includes:

[0169] The banana fiber after heat treatment and cross-linking is used to construct the reinforcing layer.

[0170] A supramolecular network rich in hydrogen bond donors is introduced on the surface of the banana fiber, which includes polydextrin and urea. The polydextrin provides host-guest interaction, and the urea acts as a hydrogen bond donor.

[0171] The banana fiber after spin coating is placed in the reinforcing layer coating solution according to the ratio of fiber mass to solution volume = 1g:100mL, the magnetic stirring rate is 200rpm, the temperature is 30℃, the soaking time is 30 minutes, the spin coating machine is used, the rotation speed is set to 400rpm, the coating time is 5 minutes, a uniform reinforcing layer is formed, the rotation acceleration is set to 200rpm / s, and vacuum drying is performed at 45℃ for 30 minutes.

[0172] The banana fiber after the construction of the reinforcing layer is used to construct the flexible layer, and a membrane cloth is obtained.

[0173] By introducing the flexible layer, the tear resistance and ductility of the membrane cloth are improved. The flexible layer includes PVA and graphene. PVA provides flexibility, and graphene enhances thermal conductivity.

[0174] The fiber after the treatment of the reinforcing layer is soaked in the flexible layer solution according to the ratio of fiber mass to solution volume = 1g:100mL by dip coating method, the magnetic stirring rate is 250rpm, the temperature is 35℃, the soaking time is 20 minutes, the spin coating method is used, the rotation speed is set to 500rpm, the coating time is 5 minutes, and vacuum drying is performed at 45℃ for 30 minutes.

[0175] The banana fiber after the construction of the flexible layer is used to construct the functional layer.

[0176] The functional layer includes antibacterial function, waterproof function, and conductive function.

[0177] Antibacterial function, nanosilver is used, waterproof function, silicone is used, conductive function, MXene is used, through airflow spraying equipment, control spraying rate 2 mL / min, set rotation speed 600 rpm, coating time 5 minutes, and vacuum drying 50℃, time 40 minutes.

[0178] In some embodiments, vacuum annealing treatment is carried out based on the obtained film cloth, argon plasma treatment is carried out based on the film cloth after vacuum annealing treatment, and durability test is carried out based on the film cloth after argon plasma treatment, specifically including:

[0179] Vacuum annealing treatment is carried out based on the obtained film cloth.

[0180] Vacuum annealing furnace is used for treatment, temperature is set to 120℃, heating time is 1 hour, vacuum degree is set to 0.1 Pa, during heating process, temperature rising rate is 5℃ / min, temperature is maintained at 120℃ for 1 hour, during annealing process, gas emission is monitored, during cooling process, slow cooling is adopted, cooling rate is 2℃ / min, and the temperature is cooled to room temperature 25℃.

[0181] Argon plasma treatment is carried out based on the film cloth after vacuum annealing treatment.

[0182] Radio frequency argon plasma treatment equipment is used, power is set to 50 W, treatment time is 5 minutes, and argon flow is 50 sccm.

[0183] Low temperature plasma peels off trace amount of organic matter on the surface of the film cloth, improves the surface cleanliness, improves the adhesion of the supramolecular modification layer through the surface activation effect, and enhances the subsequent processing performance of the film cloth.

[0184] After the argon plasma treatment is completed, the film cloth is placed in a dust-free environment for 30 minutes, the dust-free environment is set to a temperature of 25℃ and a humidity of 30%.

[0185] Durability test is carried out based on the film cloth after argon plasma treatment.

[0186] pH3, pH5, pH7 and pH9 four kinds of buffer solutions are used for immersion test, 10 mg of film cloth sample is placed in 50 mL of buffer solution, and the temperature is set to 25℃.

[0187] Ultraviolet-visible light spectrum is used to detect the coating stability of the film cloth, and the dissolution rate of the film cloth is calculated, specifically as follows:

[0188]

[0189] D = (m0- mt) / m0x 100% wherein: D is the dissolution rate of the membrane cloth, used to measure the degree of mass loss of the membrane cloth in different pH environments, m0is the initial sample mass (mg), indicating the mass of the membrane cloth at the beginning of the experiment, mtis the sample mass (mg) after 24 hours of immersion, indicating the remaining mass of the membrane cloth after immersion in the solution, is the percentage of the mass loss of the membrane cloth, reflecting the chemical stability of the membrane cloth.

[0190] When D≤5%, it indicates that the membrane cloth has good chemical resistance, and when D>5%, the degree of supramolecular crosslinking needs to be optimized.

[0191] An electronic universal testing machine is used to test the tensile strength, with a tensile rate of 10 mm / min, and the membrane cloth sample size is 5 cm x 1 cm, with three repeated tests, and the calculation is as follows:

[0192]

[0193] wherein: σ is the tensile strength MPa, indicating the tensile capacity of the membrane cloth under external force, F is the maximum tensile force (N) borne by the membrane cloth during the test, A is the cross-sectional area (mm 2 ) of the sample, and the calculation method is as follows:

[0194] A = w x t

[0195] wherein: w is the width of the sample (mm), t is the thickness of the sample (mm), is the calculation of the maximum tensile stress per unit area, which measures the tensile strength of the membrane cloth.

[0196] When σ≥50 MPa: the mechanical properties are excellent, when σ30-50 MPa: the mechanical properties are good, and when σ<30 MPa: the reinforcing layer of the membrane cloth needs to be optimized.

[0197] In some embodiments, after the durability test, the composite material is prepared, after the preparation of the composite material, the forming process is carried out, the finished membrane cloth is obtained, the high-temperature hot pressing is carried out based on the obtained finished membrane cloth, and the cutting and packaging are carried out based on the finished membrane cloth after high-temperature hot pressing, which specifically includes:

[0198] After the durability test, the composite material is prepared.

[0199] The supramolecular modification liquid, chitosan and polylactic acid are compounded, 1% (w / v) chitosan solution is dissolved in 1% acetic acid solution, stirring at 300 rpm, temperature 50°C, 30 minutes, 5% (w / v) PLA is dissolved in dichloromethane, stirring at 400 rpm, temperature 60°C, 45 minutes.

[0200] Take the supramolecular modification liquid, gradually add the bio-based resin solution, use high shear homogenizer, through 6000 rpm, 20 minutes evenly dispersed fiber, use ultrasonic dispersion, through 40 kHz, 200 W, 30 minutes to improve the dispersibility.

[0201] Based on the composite material preparation after forming process, the finished film cloth is obtained.

[0202] Adopting PLA / PHB composite solution, the viscosity is controlled in 1000-5000 cP, and adopting wet spinning equipment, the solution is extruded, adopting 30℃ ethanol-water coagulation bath 1:1, v / v, the spinning speed is set to 5-10 m / min for wet spinning, and adopting 50℃ vacuum drying for 6 hours.

[0203] Adopting PLA / PHB composite solution concentration 5%-10% w / v, through electrospinning machine, set voltage 15-25 kV, jet rate 0.5 mL / h, and through 60℃ vacuum drying for 8 hours for electrospinning.

[0204] Based on the finished film cloth obtained, high temperature hot pressing is carried out, taking the film cloth formed by wet spinning and electrospinning, placing it in a stainless steel mold, spraying release agent on the surface of the stainless steel mold, adopting 120-150℃ high temperature hot pressing for 10 minutes, applying pressure 5-10 MPa, improving the uniformity of the film cloth, after heating, adopting slow cooling, cooling rate 5℃ / min.

[0205] Based on the finished film cloth after high temperature hot pressing, cutting and packaging are carried out.

[0206] Adopting laser cutting machine, cutting the film cloth according to specifications, and adopting high-precision stamping die, batch producing finished film cloth with consistent size.

[0207] In the above content, in actual application, first, six to twelve months old banana trees are selected, banana tree pseudostems are harvested, and the outer cuticle and rough tissue are removed, and the pseudostems are cut longitudinally into two to four centimeter wide strips. A mechanical extrusion device is used to apply a pressure of five to ten megapascals to the fibers to remove non-fiber components, and the extracted fibers are immediately soaked in forty degrees Celsius warm water, stirred and washed for thirty minutes at a stirring rate of three hundred revolutions per minute, then filtered through a one hundred mesh stainless steel screen to remove sediment impurities and collect clean fibers.

[0208] Then, the cleaned banana fibers are subjected to degumming and fine purification to remove lignin, hemicellulose, and other impurities. The fibers are soaked in a 3% by mass sodium hydroxide solution at 60°C for 3 hours with continuous stirring at 200 rpm, then washed with deionized water until the pH is close to 7 to remove residual alkali. Bleaching is performed using a 5% by mass hydrogen peroxide solution at 50°C for 2 hours to further remove hemicellulose and pigments, and ultrasonic cleaning is performed using a 1:1 by volume mixture of ethanol and water at an ultrasonic frequency of 40 kHz for 30 minutes to remove lipids and residual oils.

[0209] Next, the fine-purified banana fibers are dried, screened, and stored frozen to ensure fiber stability and uniformity. Surface moisture is removed using vacuum drying at 60°C for 6 hours, and the fibers are uniformly dispersed using a mechanical carding device with a carding roller speed setting of 300 rpm. Then, a 100-mesh screen is used to screen fibers with a length of 5 to 15 mm and a diameter of 10 to 50 microns to ensure that the screened fibers meet the requirements for membrane cloth preparation. Finally, the screened fibers are placed in a freezer at -50°C for 12 hours to remove residual deep-seated moisture, and stored in a sealed vacuum bag in a dry environment at 25°C and 10% air humidity.

[0210] Meanwhile, the freeze-dried banana fibers are subjected to supramolecular modification to improve their adsorption capacity and surface activity. First, the fibers are soaked in a supramolecular modification solution at 25°C for 12 hours to form a stable coating on the fiber surface using hydrogen bonding, host-guest interactions, and electrostatic interactions. Then, a spin coating method is used with a rotation speed of 500 rpm for 5 minutes to ensure uniform deposition of the supramolecular modifier, and a heat treatment is performed at 60 to 80°C for 2 hours to promote the self-assembly of the supramolecular network and improve the water resistance and mechanical strength of the fibers.

[0211] Next, a multi-layer supramolecular composite structure is constructed to further enhance the performance of the membrane cloth. By stepwise construction of the reinforcement layer, flexible layer, and functional layer, the membrane cloth has higher mechanical strength, flexibility, and specific functions. The reinforcement layer uses a poly cyclodextrin and urea composite to provide stronger hydrogen bonding and mechanical support. The flexible layer uses a polyvinyl alcohol and graphene composite solution to improve the flexibility and tear resistance of the membrane cloth. The functional layer selects nano-silver as an antibacterial coating, silicone as a waterproof coating, or uses two-dimensional material titanium carbonitride to improve electrical conductivity according to application requirements. Each layer is coated using a spin coating and vacuum drying method with a setting temperature of 45°C and a curing time of 30 minutes to improve the interlayer bonding stability.

[0212] Finally, the final preparation of the membrane cloth is completed through wet spinning, electrospinning or high-temperature hot pressing, and cutting, packaging and performance testing are carried out. Wet spinning is adopted, a thirty-degree Celsius ethanol and water mixed coagulation bath is used to form a continuous fiber membrane, or electrospinning is adopted, a voltage of fifteen to twenty-five kilovolts is set, and a jet speed of zero point five milliliters per hour is used to prepare a nanofiber membrane. For high-density membrane cloth, high-temperature hot pressing at one hundred and twenty to one hundred and fifty degrees Celsius for ten minutes is adopted to improve the structural stability of the membrane cloth. The final membrane cloth is tested for tensile strength, air permeability and antibacterial performance to ensure that it meets the needs of high-end applications such as medical protection, flexible electronics and intelligent textiles.

Claims

1. A banana fiber based film cloth and a method for preparing the same, characterized by, The method comprises the following steps: Selecting banana fiber and performing preliminary extraction by mechanical extrusion equipment, performing degumming treatment and fine purification based on the banana fiber after preliminary extraction, performing drying and screening based on the banana fiber after degumming treatment and fine purification, and performing freeze-drying and storage; Based on the freeze-drying and storage of the banana fiber, ultrasonic cleaning is performed, pH buffer solution treatment is performed based on the ultrasonic cleaning of the banana fiber, and freeze-drying is performed based on the pH buffer solution treatment of the banana fiber; Based on the freeze-drying of the banana fiber, supermolecular host material selection is performed, solvent system preparation is performed based on the supermolecular host material selection, catalyst addition is performed based on the solvent system preparation, and solution uniform mixing is performed based on the catalyst addition; Based on the supermolecular modification liquid, the banana fiber is soaked and adsorbed, the banana fiber after soaking and adsorbing is spin-coated, and the banana fiber after spin-coating is heat-treated and cross-linked; Based on the heat treatment and cross-linking of the banana fiber, the reinforced layer is constructed, the flexible layer is constructed based on the reinforced layer construction, and the membrane cloth is obtained, and the functional layer is constructed based on the flexible layer construction of the banana fiber; Based on the obtained membrane cloth, vacuum annealing treatment is performed, argon plasma treatment is performed based on the vacuum annealing treatment of the membrane cloth, and durability test is performed based on the argon plasma treatment of the membrane cloth; Based on the durability test, a composite material is prepared, a forming process is performed based on the composite material preparation, and a finished product membrane cloth is obtained, high-temperature hot pressing is performed based on the obtained finished product membrane cloth, and cutting and packaging are performed based on the high-temperature hot pressing of the finished product membrane cloth.

2. A banana fiber based film fabric according to claim 1, wherein, Selecting banana fiber raw materials and performing preliminary extraction by mechanical extrusion equipment, performing degumming treatment and fine purification based on the banana fiber after preliminary extraction, performing drying and screening based on the banana fiber after degumming treatment and fine purification, and performing freeze-drying and storage, specifically including: Selecting banana fiber raw materials; Selecting banana trees of 6-12 months old, and cutting the banana tree pseudostems, removing the outer cutin layer and rough tissue of the banana tree pseudostems, and cutting the banana tree pseudostems longitudinally into 2-4 cm wide strips; Based on the selection of banana fiber raw materials, preliminary extraction is performed by mechanical extrusion equipment; Using a mechanical extrusion device, the non-fiber components are removed by a pressure of 5-10 MPa; The banana fiber extracted by the mechanical extrusion equipment is immediately soaked in 40℃ warm water and stirred and washed, and the precipitated fiber material is collected; The stirring and washing process is repeated 3 times until the visible impurities on the surface of the fiber are basically removed; Based on the preliminary extraction of the banana fiber, degumming treatment is performed; After stirring and washing, the banana fiber is treated with sodium hydroxide solution, the lignin and hemicellulose structure in the banana fiber are destroyed by the sodium hydroxide solution, the fiber is soaked in 3% (w / v) NaOH solution, the temperature is maintained at 60℃, the time is 3 hours, and the stirring rate is 200 rpm during the period; After soaking, deionized water is used to remove residual alkali, and the deionized water is washed until the pH value of the washing liquid is close to 7; Based on the degumming treatment of the banana fiber, fine purification is performed; Soak the banana fiber in dilute hydrochloric acid for 1 hour to remove metal ions and other inorganic impurities in the fiber, and rinse with deionized water for 5 times; Dry and screen the banana fiber after fine purification treatment; After the banana fiber is dispersed by mechanical carding equipment, it is screened through a 100-mesh screen, and fibers with a length of 5-15 mm and a diameter of 10-50 μm are retained; Freeze-drying and storage of banana fiber based on drying and screening; -50℃ freeze-drying is used to remove deep trace residual moisture, and the freeze-drying time of banana fiber is 12 hours; Store the freeze-dried banana fiber in a sealed vacuum bag and store it in a drying box, with the temperature and humidity of the drying box set at 25℃ and 10% humidity.

3. A banana fiber based film fabric according to claim 1, wherein, Based on the freeze-dried and stored banana fiber, ultrasonic cleaning is performed, and the banana fiber after ultrasonic cleaning is treated with pH buffer solution, and the banana fiber after pH buffer solution treatment is freeze-dried, which specifically includes: Ultrasonic cleaning of banana fiber after freeze-drying and storage; pH buffer solution treatment of banana fiber after ultrasonic cleaning; Prepare a pH 4-5 buffer solution with acetic acid and sodium acetate; Place the ultrasonically cleaned banana fiber in the buffer solution, with a fiber mass:solution volume ratio of 1g:50mL, a stirring rate of 150rpm, and a room temperature of 25℃, and soak for 30 minutes; Use a 200-mesh stainless steel screen to filter out the buffer solution and rinse it twice with deionized water, and take 1mL of the filtrate to detect the pH value by acid-base titration; Freeze-drying of banana fiber after pH buffer solution treatment.

4. A banana fiber based film fabric as claimed in claim 1 wherein, Based on the freeze-dried banana fiber, select a supramolecular host material, prepare a solvent system after selecting a supramolecular host material, add a catalyst after preparing a solvent system, and uniformly mix the solution after adding a catalyst, which specifically includes: Selection of supramolecular host material based on freeze-dried banana fiber; According to the hydrophilicity and adsorption characteristics of banana fiber, polydioxane, cucurbituril, amide hydrogen bond donor and imidazole salt are used as host materials; Preparation of solvent system after selection of supramolecular host material; Use dimethyl sulfoxide as a polar solvent, and use ethanol-water mixed solvent to reduce the surface tension of the solvent; Use DMSO single solvent system for high solubility supramolecule, and use ethanol-water mixed solvent system for supramolecule with both water solubility and solvent dispersibility; Use a magnetic stirrer to stir the solvent system preparation, set the temperature to 50℃, the stirring rate to 400rpm, and the time to 15 minutes; Addition of catalyst after preparation of solvent system; Use sodium p-hydroxybenzenesulfonate as a water-soluble catalyst, and use a magnetic stirrer to stir at a stirring rate of 600rpm, a temperature of 45℃, and a time of 10 minutes, and use a 200-mesh stainless steel screen to filter out undissolved catalyst particles; Uniformly mix the solution after adding the catalyst. The supermolecular material is gradually added into the preheated solvent system, 10% material is added every 5 minutes, 600 rpm magnetic stirring is adopted for 60 minutes, and the temperature is kept at 50℃±2℃ during stirring; The ultrasonic disperser is adopted, the frequency is set to 40 kHz, 200 W is adopted for ultrasonic treatment for 20 minutes; After stirring is completed, the solution is cooled to 25℃, is left standing for 12 hours, and the transmittance of the supermolecular solution is detected by using ultraviolet-visible spectroscopy; If the transmittance of the solution is greater than 90%, it represents that the solution is uniform and stable, otherwise, the ultrasonic treatment time needs to be increased or the solution concentration needs to be reduced, and the supermolecular modified liquid is obtained.

5. A banana fiber based film fabric as claimed in claim 1 wherein, Based on the supermolecular modified liquid, the banana fiber is soaked and adsorbed, based on the banana fiber after soaking and adsorption, the banana fiber is coated by rotation, and based on the banana fiber after rotation coating, the banana fiber is crosslinked by heat treatment, and specifically includes: The banana fiber is soaked and adsorbed based on the supermolecular modified liquid; The banana fiber after soaking and adsorption is coated by rotation; The rotation coating technology is used to uniformly deposit the supermolecular modifier on the fiber surface, the rotation coating machine is adopted, the rotation speed is set to 500 rpm, the coating time is 5 minutes, the rotation acceleration is set to 300 rpm / s, the soaked fiber is put into the rotation coating machine, the fiber is coated by layer-by-layer coating, the fiber is left standing for 5 minutes after each coating, the previous coating film is dried, and the next coating is carried out, and the rotation coating is repeated for 3 rounds to form a multi-layer supermolecular modified coating; Low-temperature drying is adopted during coating, and the temperature is set to 40℃, and the time is 30 minutes; The banana fiber after rotation coating is crosslinked by heat treatment; The supermolecular modified layer and the fiber surface form stable chemical bonding through heat treatment, the heat treatment parameters are set as follows: the temperature range is set to 60-80℃, and the time is maintained for 2 hours; The intermolecular hydrogen bond is rearranged through heat treatment, the poly cyclodextrin supermolecular host is more tightly packed on the active sites on the surface of the banana fiber during heating, and the molecular chain segments are rearranged under the action of temperature; The fiber after heat treatment is slowly cooled to room temperature 25℃.

6. A banana fiber based film fabric as claimed in claim 1 wherein, Based on the banana fiber after crosslinking by heat treatment, an enhancement layer is constructed, based on the banana fiber after construction of the enhancement layer, a flexible layer is constructed, and based on the banana fiber after construction of the flexible layer, a functional layer is constructed, and specifically includes: The banana fiber after crosslinking by heat treatment is used to construct an enhancement layer; The supermolecular network rich in hydrogen bond donors is introduced on the surface of the banana fiber, the supermolecular network includes poly cyclodextrin and urea, the poly cyclodextrin provides host-guest interaction, and the urea acts as a hydrogen bond donor; The banana fiber after rotation coating is taken, the ratio of fiber mass to solution volume is 1g:100mL, the banana fiber is placed in the enhancement layer coating solution, the magnetic stirring rate is 200 rpm, the temperature is 30℃, the soaking time is 30 minutes, the rotation coating machine is adopted, the rotation speed is set to 400 rpm, the coating time is 5 minutes, a uniform enhancement layer is formed, the rotation acceleration is set to 200 rpm / s, and vacuum drying is carried out at 45℃ for 30 minutes; The banana fiber after construction of the enhancement layer is used to construct a flexible layer, and a film cloth is obtained. By introducing a flexible layer, the tear resistance and ductility of the membrane cloth are improved, the flexible layer includes PVA and graphene, PVA provides flexibility, and graphene endows enhanced thermal conductivity; Based on the construction of the flexible layer, the banana fiber is constructed; The functional layer includes antibacterial function, waterproof function and conductive function; The antibacterial function adopts nano-silver, the waterproof function adopts siloxane, and the conductive function adopts MXene. Through the airflow spraying equipment, the spraying rate is controlled at 2 mL / min, the rotating speed is set at 600 rpm, the coating time is 5 minutes, and vacuum drying is carried out at 50℃ for 40 minutes.

7. A banana fiber based film fabric as claimed in claim 1 wherein, Based on the obtained membrane cloth, vacuum annealing treatment is carried out, based on the membrane cloth after vacuum annealing treatment, argon plasma treatment is carried out, based on the membrane cloth after argon plasma treatment, durability test is carried out, specifically including: Based on the obtained membrane cloth, vacuum annealing treatment is carried out; Based on the membrane cloth after vacuum annealing treatment, argon plasma treatment is carried out; Using a radio frequency argon plasma treatment device, set the power to 50W, the treatment time to 5 minutes, and the argon flow rate to 50sccm; After argon plasma treatment is completed, the membrane cloth is placed in a dust-free environment for 30 minutes, and the dust-free environment is set to a temperature of 25℃ and a humidity of 30%; Based on the membrane cloth after argon plasma treatment, durability test is carried out; Use pH3, pH5, pH7 and pH9 four kinds of buffer solution for immersion test, take 10mg of membrane cloth sample, place in 50mL buffer solution, stand for 24 hours, and set the temperature to 25℃; Use ultraviolet-visible light spectrum to detect the stability of the membrane cloth coating, calculate the dissolution rate of the membrane cloth, specifically: In the formula: D is the dissolution rate of the film cloth, which is used to measure the degree of mass loss of the film cloth in different pH environments, m_0 is the initial sample mass (mg), indicating the mass of the film cloth at the beginning of the experiment, m_t is the sample mass (mg) after soaking for 24 hours, indicating the remaining mass of the film cloth after soaking in the solution, is the percentage of the mass loss of the film cloth, which reflects the chemical stability of the film cloth; When D≤5%, it indicates that the membrane cloth has good chemical resistance, when D>5%, the supermolecular crosslinking degree needs to be optimized; Use an electronic universal testing machine to test the tensile strength, set the tensile rate to 10mm / min, take the membrane cloth sample size 5cm×1cm, test three times, and calculate specifically: Where: σ is the tensile strength in MPa, which indicates the tensile capacity of the film under the action of external force, F is the maximum tensile force (N) borne by the film during the test, A is the cross-sectional area of the sample (mm 2 ), and the calculation is as follows: A = w × t wherein: w is the width of the sample in mm, t is the thickness of the sample in mm, is the maximum tensile stress per unit area, which measures the tensile strength of the film cloth; When σ≥50MPa: good mechanical properties, when σ 30-50MPa: good mechanical properties, when σ<30MPa: the reinforcing layer of the membrane cloth needs to be optimized.

8. A banana fiber based film fabric according to claim 1, wherein, Based on the durability test, composite materials are prepared, based on the composite material preparation, forming process is carried out, and the finished membrane cloth is obtained, based on the obtained finished membrane cloth, high temperature hot pressing is carried out, based on the finished membrane cloth after high temperature hot pressing, cutting and packaging are carried out, specifically including: Based on the durability test, composite materials are prepared; Based on the composite material preparation, forming process is carried out, and the finished membrane cloth is obtained; Use PLA / PHB composite solution with viscosity controlled at 1000-5000cP, and use wet spinning equipment to extrude the solution, use 30℃ ethanol-water coagulation bath 1:1, v / v, spinning speed set to 5-10m / min for wet spinning, and use 50℃ vacuum drying for 6 hours; Use PLA / PHB composite solution with concentration of 5%-10% w / v, through electrostatic spinning machine, set voltage to 15-25kV, jet speed to 0.5mL / h, and through 60℃ vacuum drying for 8 hours for electrostatic spinning; Based on the resulting finished film cloth, take wet spinning and electrospinning forming film cloth, placed in stainless steel mold, the surface of the stainless steel mold is sprayed with release agent, using 120-150 DEG C high temperature hot pressing 10 minutes, the pressure is 5-10 MPa, improve the uniformity of the film cloth, after heating, slow cooling, cooling rate 5 DEG C / min; Based on the finished film cloth after high temperature hot pressing, cutting and packaging; Using laser cutting machine, cutting film cloth according to specifications, and using high precision stamping die, batch production of finished film cloth with consistent size.

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