Peanut skin extract / cystose co-blended solution with antibacterial function and high mechanical property and application thereof in fibers and membranes

Abstract

The application discloses a peanut skin extract / chitosan blended solution with antibacterial function and high mechanical property and application in fibers and films, and belongs to the technical field of functional textile materials. The peanut skin extract is prepared by using a solvent extraction method, and then the amino groups on the chitosan and the phenolic hydroxyl groups on the peanut skin extract are combined together through ionic crosslinking, so as to prepare the peanut skin extract / chitosan blended solution. Finally, the peanut skin extract / chitosan blended solution is spun into fibers or cast into films, so as to improve the mechanical property, hydrophobic property, antibacterial property and the like of the fibers and the films.

Description

Technical Field

[0001] This invention relates to a peanut skin extract / chitosan blend with antibacterial function and high mechanical properties, and its application in fibers and membranes, belonging to the field of functional textile materials technology. Background Technology

[0002] With increasing environmental awareness, developing environmentally friendly and biodegradable materials has become an important direction for scientific research and industrial applications. Chitosan, as a natural polymer, has shown great application potential in the fields of clothing, pharmaceuticals, and food packaging due to its good biocompatibility and biodegradability. However, traditional chitosan films are too hydrophilic, have poor mechanical properties, and their antioxidant and antibacterial capabilities still need improvement, which limits their application.

[0003] Peanut skins are widely available and inexpensive, and as a byproduct, most are treated as animal feed or waste. However, peanut skins are rich in polyphenolic compounds, which have significant antioxidant and antibacterial activities, and are not fully utilized.

[0004] Some researchers have studied the application of peanut skin extract as an additive in composite films. For example, Qingyin Dai et al. (Dai, Qingyin; Huang, Xi; Jia, Ruijing; Fang, Yanyuan; Qin, Zhiyong. Development of antibacterial film based on alginate fiber, and peanut skin extract for food packaging[J]. Journal of Food Engineering, 2022, Vol.330:111106) used sodium alginate / cellulose nanofibers as the substrate, added peanut skin extract, and used Ca... 2+Crosslinking was used to prepare an antibacterial composite film for fruit preservation, and the effect of the concentration of added peanut skin extract on the structural properties of the composite film was studied. Wenbo Meng et al. (Wenbo Meng; Jingying Shi; Xiaoyan Zhang; Huan Lian; Qingguo Wang; Yong Peng. Effects of peanut shell and skin extracts on the antioxidantability, physical and structural properties of starch-chitosan active packaging films[J]. International Journal of Biological Macromolecules, 2020, Vol.152:137-146) studied the antioxidant capacity of peanut shell and peanut skin extracts and their effects on the physical and structural properties of starch-chitosan films. The results showed that the antioxidant capacity of peanut skin extract was significantly higher than that of peanut shell and it improved the tensile strength of the composite film. Ahreum et al. (Ju, A.; Song, KB. Active biodegradable films based on water soluble polysaccharides from white jelly mushroom (Tremella fuciformis) containing roasted peanut skin) Using water-soluble polysaccharides from Tremella fuciformis as the main raw material, different concentrations of peanut skin extract were added to prepare biodegradable Tremella fuciformis polysaccharide membranes. The study found that the addition of peanut skin extract could improve the surface hydrophobicity and antioxidant capacity of the polysaccharide membranes.

[0005] However, chitosan, a product of chitin deacetylation, is the only basic polysaccharide among natural polysaccharides. The -NH2 group at the C2 position of chitosan makes its chemical structure more compact and enhances intramolecular hydrogen bonding. Currently, some natural polyphenols are routinely added to chitosan systems. For example, CN 111234324A discloses a multifunctional chitosan / gallium tannin blend membrane and its preparation method, which utilizes gallium tannin to improve the performance of the chitosan membrane. Peanut skin extract-modified chitosan not only improves the mechanical properties of chitosan but also enhances its antibacterial properties. Furthermore, the abundant active ingredients in peanut skin extract, such as resveratrol, tannic acid, proanthocyanidins, and rich sterol esters and glycerides, have functions such as improving platelet quality and showing good therapeutic effects on various hemorrhagic diseases. The combination of these two methods holds promise for applications in the field of medical textiles. Summary of the Invention

[0006] [Technical Issues]

[0007] Peanut skin extract was not used in the chitosan system.

[0008] [Technical Solution]

[0009] To address the aforementioned issues, this invention first prepares peanut skin extract using solvent extraction. Then, it utilizes the ionic crosslinking between the amino groups on chitosan and the phenolic hydroxyl groups on the peanut skin extract to prepare a peanut skin extract / chitosan blend. Finally, the peanut skin extract / chitosan blend is spun into fibers or cast into membranes to improve the mechanical properties, hydrophobic properties, and antibacterial properties of the fibers and membranes.

[0010] The first objective of this invention is to provide a method for preparing a peanut skin extract / chitosan blend, comprising the following steps:

[0011] (1) Peanut skin powder was added to an ethanol solution with a mass concentration of 0-100% for extraction. After extraction, the mixture was allowed to stand, filtered, and the filtrate was evaporated and dried to obtain peanut skin extract.

[0012] (2) Dissolve peanut skin extract in water, then add chitosan and acetic acid and mix well to obtain peanut skin extract / chitosan blend.

[0013] In one embodiment of the present invention, the ratio of peanut skin powder to ethanol solution in step (1) is 1g:25-35mL.

[0014] In one embodiment of the present invention, the extraction in step (1) is performed at 45-55°C for 50-70 min.

[0015] In one embodiment of the present invention, the evaporation in step (1) is carried out at 35-45°C for 20-30 hours.

[0016] In one embodiment of the present invention, the mass concentration of chitosan in water in step (2) is 2-3%.

[0017] In one embodiment of the present invention, the mass concentration of acetic acid in water in step (2) is 1.5-2.5%.

[0018] In one embodiment of the present invention, the amount of peanut skin extract used in step (2) is 3-15% of the mass of chitosan.

[0019] In one embodiment of the present invention, the peanut skin extract is dissolved in water in step (2) by mechanical stirring at a speed of 300 rpm for 2-5 hours.

[0020] In one embodiment of the present invention, the mixing in step (2) is carried out by stirring at 50-60°C and 500-1000 rpm for 4-12 hours.

[0021] In one embodiment of the present invention, if the reaction temperature is not specifically specified in steps (1) and (2), the reaction is carried out at room temperature, which is 20-30°C.

[0022] The second objective of this invention is to prepare a peanut skin extract / chitosan blend using the method described herein.

[0023] The third objective of this invention is to provide a method for preparing peanut skin extract / chitosan blended fibers, which uses the peanut skin extract / chitosan blend solution described in this invention.

[0024] In one embodiment of the present invention, the method includes the following steps:

[0025] Peanut skin extract / chitosan blend solution was degassed and placed in a spinning solution injection container. The fiber was propelled through a coagulation bath at a certain speed. The fiber was then appropriately drawn and wound onto a winding device for collection. The fiber was washed until it was neutral. The neutral fiber was then immersed in a glycerol solution, removed, and dried to obtain peanut skin extract / chitosan blend fiber.

[0026] In one embodiment of the present invention, degassing is performed by static degassing.

[0027] In one embodiment of the present invention, the propulsion speed is 0.4-0.6 mL / min.

[0028] In one embodiment of the present invention, the coagulation bath is a mixed solution of NaOH solution and ethanol, wherein the mass concentration of NaOH solution is 4-6% and the solvent is water; the mass ratio of NaOH solution to ethanol is 2:1.

[0029] In one embodiment of the present invention, the winding temperature is 20-30°C and the winding speed is 40-60 r / min.

[0030] In one embodiment of the present invention, the washing is carried out using water at a temperature of 20-30°C.

[0031] In one embodiment of the present invention, the volume concentration of the glycerol solution is 0.5-1.5%, and the solvent is water.

[0032] In one embodiment of the present invention, the immersion is performed at 20-30°C (room temperature) for 1-3 hours.

[0033] In one embodiment of the invention, drying is natural air drying.

[0034] In one embodiment of the present invention, when the peanut skin extract / chitosan blend is used for spinning, the preparation method of the peanut skin extract / chitosan blend is as follows:

[0035] (1) Peanut skin powder was added to an ethanol solution with a mass concentration of 0-100% for extraction. After extraction, the mixture was allowed to stand, filtered, and the filtrate was evaporated and dried to obtain peanut skin extract.

[0036] (2) Dissolve peanut skin extract in extraction solvent, stir at 300 rpm for 2 h, then add chitosan and acetic acid and mix evenly to obtain peanut skin extract / chitosan blend; the mixing is carried out at 60℃ and 600 rpm for 12 h; the amount of peanut skin extract is 3-15% of the mass of chitosan, and the mass concentration of chitosan in water is 2.5%.

[0037] The fourth objective of this invention is to prepare peanut skin extract / chitosan blended fibers using the method described herein.

[0038] The fifth objective of this invention is to provide a method for preparing a peanut skin extract / chitosan blend membrane, which uses the peanut skin extract / chitosan blend solution described in this invention.

[0039] In one embodiment of the present invention, the method includes the following steps:

[0040] The peanut skin extract / chitosan blend was poured into a mold and dried to obtain a peanut skin extract / chitosan blend membrane.

[0041] In one embodiment of the present invention, the drying is natural air drying.

[0042] In one embodiment of the present invention, when the peanut skin extract / chitosan blend is used to prepare a membrane, the preparation method of the peanut skin extract / chitosan blend is as follows:

[0043] (1) Peanut skin powder was added to an ethanol solution with a mass concentration of 0-100% for extraction. After extraction, the mixture was allowed to stand, filtered, and the filtrate was evaporated and dried to obtain peanut skin extract.

[0044] (2) Dissolve peanut skin extract in extraction solvent, stir at 300 rpm for 2 h, then add chitosan and acetic acid and mix evenly to obtain peanut skin extract / chitosan blend; the mixing is carried out at 50℃ and 600 rpm for 6 h; the amount of peanut skin extract is 5-15% of the mass of chitosan, and the mass concentration of chitosan in water is 2%.

[0045] The sixth objective of this invention is to prepare a peanut skin extract / chitosan blend membrane using the method described herein.

[0046] The seventh objective of this invention is the application of the peanut skin extract / chitosan blend, peanut skin extract / chitosan blend fiber, and peanut skin extract / chitosan blend membrane described herein in the field of antibacterial composite materials.

[0047] The eighth objective of this invention is to provide a method for simultaneously improving the mechanical properties, hydrophobic properties, and antibacterial properties of composite materials, which employs the peanut skin extract / chitosan blend liquid, peanut skin extract / chitosan blend fiber, and peanut skin extract / chitosan blend membrane described in this invention.

[0048] [Beneficial Effects]

[0049] (1) The peanut skin extract / chitosan blend of the present invention has good compatibility between chitosan and peanut skin extract.

[0050] (2) When the peanut skin extract / chitosan blend of the present invention is used as a spinning solution to prepare fibers, the apparent viscosity and tensile rheological properties of the spinning solution are improved compared with those of pure chitosan spinning solution, and the preparation method is simpler.

[0051] (3) Compared with pure chitosan fiber, the initial thermal decomposition temperature of peanut skin extract / chitosan blend fiber is increased, and the temperature corresponding to the highest thermal decomposition rate is increased by about 10℃; dry strength, wet strength and wet breaking elongation are all improved; and antibacterial properties are enhanced.

[0052] (4) Compared with pure chitosan membrane, peanut skin extract / chitosan blend membrane has increased modulus and hardness; increased roughness and improved surface hydrophobicity; increased initial thermal decomposition temperature; increased dry strength, wet strength and wet elongation at break; and in terms of color, L value is significantly reduced and a*, b* and c* values ​​are significantly increased. Attached Figure Description

[0053] Figure 1 The results show the viscosity test results for the peanut skin extract / chitosan blend and the pure chitosan solution.

[0054] Figure 2 The tensile rheological properties of peanut skin extract / chitosan blend and pure chitosan solution are shown in the following figures: (a) CS / PS-W series fibers; (b) CS / PS-M series fibers; (c) CS / PS-E series fibers; and (d) CS, CS / PS-W-15%, CS / PS-M-15%, and CS / PS-E-15% fibers.

[0055] Figure 3 SEM images of the longitudinal surface of the fibers are shown, where (a) is CS fiber (300 μm); (b) is CS fiber (10 μm); (c) is CS / PS-W-9% blended fiber (300 μm); (d) is CS / PS-W-9% blended fiber (10 μm); (e) is CS / PS-M-9% blended fiber (300 μm); (f) is CS / PS-M-9% blended fiber (10 μm); (g) is CS / PS-E-9% blended fiber (300 μm); and (h) is CS / PS-E-9% blended fiber (10 μm).

[0056] Figure 4 SEM images of the fiber fracture surfaces are shown, where (a) is CS fiber (300 μm); (b) is CS fiber (10 μm); (c) is CS / PS-W-9% blended fiber (300 μm); (d) is CS / PS-W-9% blended fiber (10 μm); (e) is CS / PS-M-9% blended fiber (300 μm); (f) is CS / PS-M-9% blended fiber (10 μm); (g) is CS / PS-E-9% blended fiber (300 μm); and (h) is CS / PS-E-9% blended fiber (10 μm).

[0057] Figure 5 Infrared spectra of CS fiber, CS / PS-W-9% blended fiber, CS / PS-M-9% blended fiber, and CS / PS-E-9% blended fiber.

[0058] Figure 6The results show the thermal stability of CS fiber, CS / PS-W-9% blended fiber, CS / PS-M-9% blended fiber, and CS / PS-E-9% blended fiber, where (a) is the mass surplus and (b) is the mass loss rate.

[0059] Figure 7 The mechanical properties of peanut skin extract / chitosan blended fibers are shown in the test results, where (a) represents breaking strength and (b) represents breaking elongation.

[0060] Figure 8 The results show the wet breaking strength and wet breaking elongation of the peanut skin extract / chitosan blended fiber, where (a) represents the wet breaking strength and (b) represents the wet breaking elongation.

[0061] Figure 9 SEM images of the surfaces of (a) CS membrane, (b) CS / PS-W-10% membrane, (c) CS / PS-M-10% membrane, and (d) CS / PS-E-10% membrane.

[0062] Figure 10 SEM images of the fracture surfaces of (a) CS membrane, (b) CS / PS-W-10% membrane, (c) CS / PS-M-10% membrane, and (d) CS / PS-E-10% membrane.

[0063] Figure 11 FT-IR spectra of CS membrane, CS / PS-W-15% membrane, CS / PS-M-15% membrane, and CS / PS-E-15% membrane.

[0064] Figure 12 The pressure-displacement relationship is shown for CS membranes and CS / PS-W-10% membranes, CS / PS-M-10% membranes, and CS / PS-E-10% blend membranes.

[0065] Figure 13 Hydrophilicity and hydrophobicity of CS membranes and CS / PS-W-10% membranes, CS / PS-M-10% membranes, and CS / PS-E-10% blend membranes.

[0066] Figure 14 (a) thermogravimetric and (b) mass loss rate curves for CS membranes and CS / PS-W-10% membranes, CS / PS-M-10% membranes, and CS / PS-E-10% blend membranes.

[0067] Figure 15 (a) breaking strength and (b) breaking elongation for CS membrane and CS / PS-W-10% membrane, CS / PS-M-10% membrane, and CS / PS-E-10% blend membrane.

[0068] Figure 16(a) wet breaking strength and (b) wet breaking elongation for CS membrane and CS / PS-W-10% membrane, CS / PS-M-10% membrane, and CS / PS-E-10% blend membrane.

[0069] Figure 17 This is a photograph of the membrane prepared in Comparative Example 3.

[0070] Figure 18 This is a photograph of the membrane prepared in Comparative Example 4.

[0071] Figure 19 This is a photograph of the membrane prepared in Comparative Example 5.

[0072] Figure 20 This is a photograph of the membrane prepared in Comparative Example 6. Detailed Implementation

[0073] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explanation of the present invention and are not intended to limit the present invention.

[0074] Test method:

[0075] 1. Apparent viscosity

[0076] The apparent viscosity of different spinning solutions was measured using an NDJ-79 rotational viscometer at 25°C. Rotors No. 2 or No. 3 were used, and the speed was 750 r / min.

[0077] 2. Tensile rheological properties

[0078] The rheological properties of the spinning solution under tension were tested using a HAAKE CaBER 1 tensile rheometer (Thermo Fisher Scientific, USA). A small sample (<1 mL) was placed between two discs, and the upper disc was rapidly separated from the lower disc at a pre-set strain rate, forming an unstable fluid filament. A laser micrometer was used to monitor the change in the midpoint diameter of the gradually thinning fluid filament over time.

[0079] 3. Microstructure

[0080] The samples were photographed using a field emission electron microscope at an accelerating voltage of 5 kV to observe the morphology and structure of the surface and fracture surfaces of the fibers and membranes; the fracture surfaces were obtained from tensile fracture.

[0081] 4. Fourier transform infrared spectrum

[0082] The FTIR spectra of the fibers and membranes were measured using a Fourier transform infrared spectroscopy (FTIR) instrument. The fibers and membranes were dried in a vacuum oven at 50°C for 12 hours, and then... (The sentence is incomplete and requires more context to translate accurately.) -1 The resolution record is 4000 to 500 cm. -1 The spectrum.

[0083] 5. Fiber mechanical property testing

[0084] The sample was cut into strips of a specific size of 20cm and placed at 25℃ and 60% relative humidity for 48h to equilibrate. The dry strength and elongation at break of the fiber were tested on a tensile testing machine. After being fully soaked in water and the surface water was wiped dry, the wet strength and elongation at break of the fiber were tested on a tensile testing machine.

[0085] Test parameters: clamping distance 50 mm, tensile speed 100 mm / min, at least 20 specimens of each type. The diameter of the fiber within the clamping distance was measured using a thickness gauge, and the measured thickness value was accurate to 0.001 mm.

[0086] 6. Membrane mechanical property testing

[0087] The sample was cut into strips of a specific size of 10×0.5cm and placed at 25℃ and 60% relative humidity for 48h to equilibrate. The dry strength and elongation at break of the film were tested on a tensile testing machine. After being fully immersed in water and the surface water was wiped dry, the wet strength and elongation at break of the film were tested on a tensile testing machine.

[0088] Test parameters: 1.3.3 The clamping distance is 50 mm, the stretching speed is 100 mm / min, and at least 10 samples of each type are used. The thickness of the inner membrane of the clamping distance is measured using a thickness gauge, and the measured thickness value is accurate to 0.001 mm.

[0089] 7. Antibacterial properties

[0090] The antibacterial properties of the fibers were determined according to GB / T 20944.3-2008 "Evaluation of antimicrobial properties of textiles - Part 3: Vibration method". The bacterial growth of the fibers was observed, and the bacterial reduction rate (%) of Staphylococcus aureus and Escherichia coli in the sample fibers was calculated according to the formula.

[0091]

[0092] In the formula: Y is the antibacterial rate of the sample (%); W is the average number of colonies in the three control samples (cells); Q is the average number of colonies in the three samples (cells).

[0093] 8. Thermal stability test

[0094] The thermal stability of the fibers and membranes was analyzed using a thermogravimetric analyzer. The samples were heated from 30°C to 800°C at a heating rate of 20°C / min in a nitrogen atmosphere at a flow rate of 50 mL / min.

[0095] 9. Testing of the micromechanical properties of the membrane

[0096] The surface roughness and micromechanical properties of the film were detected using a nanoindenter with a pressure of 1000 μN applied by the probe.

[0097] 10. Surface hydrophilicity and hydrophobicity test

[0098] The contact angle of the membrane was measured using a contact angle meter for 3 minutes, with photos taken every 30 seconds. Five measurements were taken for each sample, and the average value was recorded. The water droplet size was 5 μL.

[0099] 11. Color Feature Value Test

[0100] After the membrane was pretreated for 24 hours under standard conditions of 20±2℃ and 65±3% humidity, the color characteristic values ​​L*, a*, b*, c*, h and K / S value of the fabric were measured using a D65 light source and a 10° field of view.

[0101] The color characteristic value of each sample is the average value of 5 test points.

[0102] Raw materials used in the examples and comparative examples:

[0103] Peanut skins: purchased from Anhui Shengshi Biotechnology Co., Ltd.

[0104] Peanut skin powder: obtained by drying and pulverizing peanut skins, with a particle size of 7μm;

[0105] Chitosan: Deacetylation degree 95%, viscosity 1250 mPa·s, purchased from Huaifang Haizhiyuan Biological Products Co., Ltd.

[0106] Acetic acid, anhydrous ethanol, and sodium hydroxide were all of analytical grade and purchased from Sinopharm Chemical Reagent Co., Ltd.

[0107] In the examples, the percentages (%) without specific content are mass percentages; the solutions without specific solvents are water-based; and the reaction temperatures without specific temperatures are at room temperature (20-30°C).

[0108] Example 1

[0109] A method for preparing a peanut skin extract / chitosan blend includes the following steps:

[0110] (1) Add 10g of peanut skin powder to 300mL of 50% ethanol solution and extract at 50℃ for 60min. After extraction, let stand, filter, evaporate the filtrate at 40℃ for 24h, and dry to obtain peanut skin extract.

[0111] (2) Dissolve peanut skin extract in water and stir at 300 rpm for 2 h to ensure that the peanut extract is fully dissolved in the water. Then add chitosan and acetic acid and stir at 600 rpm and 60°C in a water bath for 12 h to mix evenly to obtain peanut skin extract / chitosan blend (CS / PS-M-12%). The mass concentration of chitosan in water is 2.5%, the mass concentration of acetic acid in water is 2%, and the amount of peanut skin extract is 12% of the mass of chitosan.

[0112] Example 2

[0113] The amount of peanut skin extract in step (2) of Example 1 was adjusted to 3%, 6%, 9%, and 15% of the chitosan mass, while other steps remained the same as in Example 1, to obtain peanut skin extract / chitosan blends (CS / PS-M-3%, CS / PS-M-6%, CS / PS-M-9%, CS / PS-M-15%).

[0114] Example 3

[0115] The ethanol solution with a mass concentration of 50% in step (1) of Example 1 was changed to water, while other steps remained the same as in Example 1, to obtain a peanut skin extract / chitosan blend (CS / PS-W-12%).

[0116] Example 4

[0117] The amount of peanut skin extract in step (2) of Example 3 was adjusted to 3%, 6%, 9%, and 15% of the chitosan mass, while other steps remained the same as in Example 3, to obtain peanut skin extract / chitosan blends (CS / PS-W-3%, CS / PS-W-6%, CS / PS-W-9%, CS / PS-W-15%).

[0118] Example 5

[0119] The ethanol solution with a mass concentration of 50% in step (1) of Example 1 was changed to anhydrous ethanol, while the rest remained the same as in Example 1, to obtain a peanut skin extract / chitosan blend (CS / PS-E-12%).

[0120] Example 6

[0121] The amount of peanut skin extract in step (2) of Example 3 was adjusted to 3%, 6%, 9%, and 15% of the chitosan mass, while other aspects remained the same as in Example 3, to obtain peanut skin extract / chitosan blends (CS / PS-E-3%, CS / PS-E-6%, CS / PS-E-9%, CS / PS-E-15%).

[0122] Comparative Example 1

[0123] The peanut skin extract in Example 1 was omitted, and everything else remained the same as in Example 1 to obtain a pure chitosan solution (CS).

[0124] The products obtained in Examples 1-6 and Comparative Example 1 were subjected to performance tests, and the test results are as follows:

[0125] Figure 1 Viscosity test results for peanut skin extract / chitosan blend and pure chitosan solution. From Figure 1 It can be seen that the pure chitosan spinning solution has the lowest viscosity, while the viscosity of the peanut skin extract / chitosan blend increases with the increase of peanut skin extract content, with the CS / PS-M-15% blend having the highest viscosity. When the viscosity of the blend is high, the nascent fibrils are less prone to breakage and exhibit good spinnability.

[0126] Figure 2 The tensile rheological properties of peanut skin extract / chitosan blend and pure chitosan solution are shown in the figures; (a) represents CS / PS-W series fibers; (b) represents CS / PS-M series fibers; (c) represents CS / PS-E series fibers; and (d) represents CS, CS / PS-W-15%, CS / PS-M-15%, and CS / PS-E-15% fibers. Figure 2 It can be seen that the fracture time of CS / PS-W, CS / PS-M, and CS / PS-E blends from the start of stretching to breakage is significantly increased compared with pure chitosan solution, and the fracture is less likely to occur with increasing peanut skin extract content. Compared with pure chitosan solution, the CS / PS blends require a longer time to stretch to the same diameter. The longer fracture time indicates that the addition of peanut skin extract improves the extensibility of the blends, which may result in better spinnability. Good spinnability can improve the mechanical properties of fibers. With improved spinnability, the molecular chains in the fiber can be better aligned to eliminate fiber defects, thereby improving its mechanical properties.

[0127] Example 7

[0128] A method for preparing peanut skin extract / chitosan blended fiber includes the following steps:

[0129] The pure chitosan solution prepared in Comparative Example 1 and the peanut skin extract / chitosan blend prepared in Examples 1-6 were allowed to stand for degassing. They were then placed in a micro-injection pump and propelled at a flow rate of 0.5 mL / min, allowing the fibers to pass through a coagulation bath (a mixture of NaOH solution and ethanol with a mass ratio of 2:1, and the NaOH solution had a mass concentration of 5%) at a certain speed. At room temperature, the fibers were appropriately stretched and wound onto a winding device at a speed of 50 r / min for collection. The fibers were washed with water at 25°C until they became neutral. The neutral fibers were then immersed in a 1% glycerol solution at room temperature for 2 hours, removed, and air-dried to obtain peanut skin extract / chitosan blend fibers (CS fibers, CS / PS blend fibers).

[0130] The obtained peanut skin extract / chitosan blend fiber was subjected to performance testing, and the test results are as follows:

[0131] Figure 3 SEM images of the longitudinal surface of the fibers are shown, where (a) is CS fiber (300 μm); (b) is CS fiber (10 μm); (c) is CS / PS-W-9% blended fiber (300 μm); (d) is CS / PS-W-9% blended fiber (10 μm); (e) is CS / PS-M-9% blended fiber (300 μm); (f) is CS / PS-M-9% blended fiber (10 μm); (g) is CS / PS-E-9% blended fiber (300 μm); and (h) is CS / PS-E-9% blended fiber (10 μm).

[0132] Figure 4 SEM images of the fiber fracture surfaces are shown, where (a) is CS fiber (300 μm); (b) is CS fiber (10 μm); (c) is CS / PS-W-9% blended fiber (300 μm); (d) is CS / PS-W-9% blended fiber (10 μm); (e) is CS / PS-M-9% blended fiber (300 μm); (f) is CS / PS-M-9% blended fiber (10 μm); (g) is CS / PS-E-9% blended fiber (300 μm); and (h) is CS / PS-E-9% blended fiber (10 μm).

[0133] from Figure 3 and Figure 4 It can be seen that the surface of chitosan CS fiber is smooth and flat. After adding peanut skin extract, smaller particles begin to appear on the surface of the blended fiber. The addition of peanut skin extract makes the fracture surface exhibit a tough fracture state, with a rough fracture end and no obvious large particles in the fracture surface. This indicates that the peanut skin extract and chitosan have good compatibility.

[0134] Figure 5Infrared spectra of CS fiber, CS / PS-W-9% blend fiber, CS / PS-M-9% blend fiber, and CS / PS-E-9% blend fiber. Figure 5 It can be seen that: CS fibers at 3352cm -1 The relatively broad absorption peak is due to the overlap of multiple absorption peaks from the stretching vibrations of O-H and N-H. In the infrared spectrum of the blended fibers, no new peaks appeared in the FT-IR image after the addition of peanut skin extract, indicating that the overlapping multiple absorption peaks from the O-H and N-H stretching vibrations of chitosan shifted to the lower wavenumber region. This phenomenon is mainly attributed to the intermolecular interaction between the phenolic hydroxyl groups of peanut skin extract and the hydroxyl groups of chitosan, which reduces the chemical bond constant of the participating hydroxyl groups, causing the absorption frequency to shift towards lower wavenumbers.

[0135] Figure 6 The results show the thermal stability test results for CS fiber, CS / PS-W-9% blended fiber, CS / PS-M-9% blended fiber, and CS / PS-E-9% blended fiber, where (a) is the mass surplus and (b) is the mass loss rate. Figure 6 It can be seen that the initial thermal decomposition temperature of the CS / PS blend fiber is higher than that of the CS membrane, and the temperature corresponding to the highest thermal decomposition rate of the CS / PS blend membrane is increased by about 10℃. These results indicate that the addition of PS can improve the thermal stability of the CS / PS blend fiber, mainly attributed to the intermolecular forces between chitosan molecules and peanut skin extract.

[0136] Figure 7 The mechanical properties of peanut skin extract / chitosan blended fibers are shown in the test results, where (a) represents breaking strength and (b) represents breaking elongation. Figure 8 The results show the wet breaking strength and wet breaking elongation of peanut skin extract / chitosan blended fibers, where (a) represents the wet breaking strength and (b) represents the wet breaking elongation. Figure 7 and Figure 8It can be seen that, except for the CS / PS-E blended fiber, whose tensile strength increases with increasing peanut skin content in the wet state, the tensile strength of other blended fibers under different humidity levels shows a trend of first increasing and then decreasing. When the PS content is 6%, the dry tensile strength of the blended fibers shows the most significant increase; when the PS content is 12%, the wet tensile strength of the blended fibers shows the most significant increase. In particular, compared with CS fiber, the CS / PS-M blended fiber shows a 160% increase in dry strength and a 115% increase in wet strength. Under dry conditions, the elongation at break is lower than that of pure chitosan; under fully wet conditions, the elongation at break of the blended fibers shows a trend of first increasing and then decreasing. When the PS content of CS / PS-W blended fiber is 3%, the elongation at break is 19% higher than that of CS fiber; when the PS content of CS / PS-M blended fiber is 3%, the elongation at break is 4% higher than that of CS fiber; and when the PS content of CS / PS-E blended fiber is 12%, the elongation at break is 39% higher than that of CS fiber. This is mainly attributed to the ionic cross-linking that forms between peanut skin extract and chitosan.

[0137] Table 1 shows the antibacterial rates of CS fiber and CS / PS blended fiber. As can be seen from Table 1, the bacterial reduction rate of CS / PS blended fiber is significantly higher than that of CS fiber, especially against *E. coli*. CS fiber has a bactericidal rate of 76.28% against *E. coli* and only 46.07% against *Staphylococcus aureus*, which is insufficient to meet the requirements of antimicrobial textile standards. However, the CS / PS-M-6% blended fiber has a bactericidal rate as high as 95.03% against *E. coli* and 71.20% against *Staphylococcus aureus*, thus meeting some of the requirements for antimicrobial textiles.

[0138] Table 1 Antibacterial rates of CS fibers and CS / PS blend fibers

[0139]

[0140] Example 8

[0141] A method for preparing a peanut skin extract / chitosan blend includes the following steps:

[0142] (1) Add 10g of peanut skin powder to 300mL of 50% ethanol solution and extract at 50℃ for 60min. After extraction, let stand, filter, evaporate the filtrate at 40℃ for 24h, and dry to obtain peanut skin extract.

[0143] (2) Dissolve peanut skin extract in extraction solvent and stir at 300 rpm for 2 h to fully dissolve peanut extract in water. Then add chitosan and acetic acid and stir at 600 rpm and 50°C in a water bath for 6 h to mix evenly to obtain peanut skin extract / chitosan blend (CS / PS-M-15%). The mass concentration of chitosan in water is 2%, the mass concentration of acetic acid in water is 2%, and the amount of peanut skin extract is 15% of the mass of chitosan.

[0144] Example 9

[0145] The amount of peanut skin extract in step (2) of Example 8 was adjusted to 5% and 10% of the chitosan mass; other steps remained the same as in Example 8, resulting in a peanut skin extract / chitosan blend (CS / PS-M-5%, CS / PS-M-10%).

[0146] Example 10

[0147] The ethanol solution with a mass concentration of 50% in step (1) of Example 8 was changed to water, while the rest remained the same as in Example 8, to obtain a peanut skin extract / chitosan blend (CS / PS-W-15%).

[0148] Example 11

[0149] The amount of peanut skin extract in step (2) of Example 10 was adjusted to 5% and 10% of the chitosan mass, while the rest remained the same as in Example 11, to obtain peanut skin extract / chitosan blend (CS / PS-W-5%, CS / PS-W-10%).

[0150] Example 12

[0151] The ethanol solution with a mass concentration of 50% in step (1) of Example 8 was changed to anhydrous ethanol, while the rest remained the same as in Example 8, to obtain a peanut skin extract / chitosan blend (CS / PS-E-15%).

[0152] Example 13

[0153] The amount of peanut skin extract in step (2) of Example 12 was adjusted to 5% and 10% of the chitosan mass, while the rest remained the same as in Example 12, to obtain peanut skin extract / chitosan blend (CS / PS-E-5%, CS / PS-E-10%).

[0154] Comparative Example 2

[0155] The peanut skin extract in Example 8 was omitted, and everything else remained the same as in Example 8 to obtain a pure chitosan solution (CS).

[0156] Example 14

[0157] A method for preparing a peanut skin extract / chitosan blend membrane includes the following steps:

[0158] 40g of pure chitosan solution prepared in Comparative Example 2 and 40g of peanut skin extract / chitosan blend prepared in Examples 9-13 were poured into a 15cm diameter disc and allowed to air dry naturally to obtain chitosan membrane and peanut skin extract / chitosan blend membrane.

[0159] The obtained membrane was subjected to performance testing, and the test results are as follows:

[0160] Figure 9 SEM images of the surfaces of (a) CS membrane, (b) CS / PS-W-10% membrane, (c) CS / PS-M-10% membrane, and (d) CS / PS-E-10% membrane. Figure 10 SEM images of the fracture surfaces of (a) CS membrane, (b) CS / PS-W-10% membrane, (c) CS / PS-M-10% membrane, and (d) CS / PS-E10% membrane. From... Figure 9 and Figure 10 It can be seen that the surface of the chitosan membrane is smooth and flat. After adding peanut skin extract, smaller particles began to appear on the membrane surface. The chitosan membrane showed a tendency to fracture brittlely, while the addition of peanut skin extract caused the fracture surface to exhibit a ductile fracture state with a rough fracture end. Moreover, there were no obvious large particles in the fracture surface, which indicates that the peanut skin extract and chitosan have good compatibility.

[0161] Figure 11 FT-IR spectra of CS film, CS / PS-W-15% film, CS / PS-M-15% film, and CS / PS-E-15% film. From... Figure 11 It can be seen that the CS membrane at 3223cm -1 A relatively broad absorption peak is observed, which is due to the overlap of multiple absorption peaks from the stretching vibrations of O—H and N—H. In the infrared spectrum of the blended film, no new peaks appeared in the FT-IR image when peanut skin extract was added to the film, indicating that the overlapping multiple absorption peaks of the O—H and N—H stretching vibrations of chitosan shifted to the lower wavenumber region. This phenomenon is mainly attributed to the intermolecular interaction between the phenolic hydroxyl groups of peanut skin extract and the hydroxyl groups of chitosan, which reduces the chemical bond constant of the hydroxyl groups involved in the interaction, causing its absorption frequency to shift towards lower wavenumbers.

[0162] Figure 12 Table 1 shows the pressure-displacement relationship of the CS membrane and the CS / PS-W-10% membrane, CS / PS-M-10% membrane, and CS / PS-E-10% blend membrane. Table 2 shows the micromechanical properties of the CS membrane and the CS / PS blend membrane. Figure 12As shown in Table 2, the addition of peanut skin extract increased the modulus, hardness, and roughness of the three CS / PS blend films, especially the CS / PS-M film, which exhibited a more significant effect and had a lower roughness than the other two blend films. Furthermore, the blend films were less prone to deformation under stress and recovered more easily after deformation, again with the CS / PS-M film showing a more pronounced effect. In summary, this is all attributed to the intermolecular interactions between CS and PS, which alter the structure of chitosan, making it more compact.

[0163] Table 2 Micromechanical properties of CS membranes and CS / PS blend membranes

[0164]

[0165] Figure 13 The hydrophilicity and hydrophobicity of CS membranes and CS / PS-W-10% membranes, CS / PS-M-10% membranes, and CS / PS-E-10% blend membranes were determined. Figure 13 It can be seen that the surface hydrophobicity of the three CS / PS blend membranes was improved. In particular, after 3 minutes, the contact angle of the three CS / PS blend membranes decreased by less than 13%. Compared with the CS membrane, the contact angle increased by 104%-116%. Among them, the CS / PS-E blend membrane showed a more significant effect, with a contact angle increase of 116%.

[0166] Figure 14 (a) Thermogravimetric analysis (TGA) and (b) mass loss rate curves for CS membranes and CS / PS-W-10% membranes, CS / PS-M-10% membranes, and CS / PS-E-10% blend membranes. Figure 14 It can be seen that the initial thermal decomposition temperature of the CS / PS blend membrane is higher than that of the CS membrane, and the temperature corresponding to the highest thermal decomposition rate of the CS / PS blend membrane is increased by about 10℃. These results indicate that the addition of PS can improve the thermal stability of the CS / PS blend membrane, mainly due to the intermolecular forces between chitosan molecules and peanut skin extract.

[0167] Figure 15 (a) breaking strength and (b) breaking elongation for CS membrane and CS / PS-W-10% membrane, CS / PS-M-10% membrane, and CS / PS-E-10% blend membrane. Figure 16 (a) wet breaking strength and (b) wet breaking elongation for CS membranes and CS / PS-W-10% membranes, CS / PS-M-10% membranes, and CS / PS-E-10% blend membranes. Figure 15 and Figure 16It can be seen that with the increase of peanut skin content, the tensile strength of the blended film under different humidity conditions shows a trend of first increasing and then decreasing. When the PS content is 5%, the tensile strength of the blended film increases most significantly, especially the dry strength of the CS / PS-M blended film compared with the CS film, which increases by 67% and the wet strength by 155%. Under dry conditions, the elongation at break is lower than that of pure chitosan; under fully wetted conditions, the elongation at break is higher than that of pure chitosan. When the PS content is 5%, the elongation at break of the CS / PS-E blended film is 410% higher than that of the CS film.

[0168] Table 3 shows the color characteristic values ​​of the CS membrane and the CS / PS blend membrane. As can be seen from Table 3, the brightness of the chitosan membrane significantly decreased after the addition of peanut skin extract, while the a*, b*, and c* values ​​significantly increased. Furthermore, with the increase of peanut skin extract dosage, the color of the CS / PS blend membrane became increasingly reddish and yellowish, and the color became more saturated.

[0169] Table 3 Color characteristic values ​​of CS film and CS / PS blend film

[0170]

[0171] Comparative Example 3

[0172] A method for preparing a peanut skin extract / chitosan blend membrane includes the following steps:

[0173] (1) Add 10g of peanut skin powder to 300mL of 50% ethanol solution and extract at 50℃ for 60min. After extraction, let stand, filter, evaporate the filtrate at 40℃ for 24h, and dry to obtain peanut skin extract.

[0174] (2) Chitosan was dissolved in an aqueous acetic acid solution, and then peanut skin extract was added. The mixture was stirred at 600 rpm and 50°C in a water bath for 4 hours to obtain a peanut skin extract / chitosan blend (CS / PS-M-15%). The mass concentration of chitosan in water was 2%, the mass concentration of acetic acid in water was 2%, and the amount of peanut skin extract was 15% of the mass of chitosan.

[0175] (3) Pour 40g of peanut skin extract / chitosan blend into a 15cm diameter disc and air dry to obtain a peanut skin extract / chitosan blend membrane.

[0176] The obtained peanut skin extract / chitosan blend membrane was subjected to performance testing, and the test results are as follows:

[0177] Figure 17 This is a photograph of the membrane prepared in Comparative Example 3. Figure 17 It can be seen that there are large particles on the membrane surface, and the uniformity is very poor.

[0178] Comparative Example 4

[0179] A method for preparing a peanut skin extract / chitosan blend membrane includes the following steps:

[0180] (1) Add 10g of peanut skin powder to 300mL of 50% ethanol solution and extract at 50℃ for 60min. After extraction, let stand, filter, evaporate the filtrate at 40℃ for 24h, and dry to obtain peanut skin extract.

[0181] (2) Dissolve peanut skin extract in water and stir at 300 rpm for 2 hours to ensure that the peanut extract is fully dissolved in the water. Then add chitosan and acetic acid and stir at 600 rpm and 50°C in a water bath for 4 hours to mix evenly to obtain peanut skin extract / chitosan blend (CS / PS-M-15%). The mass concentration of chitosan in water is 2%, the mass concentration of acetic acid in water is 2%, and the amount of peanut skin extract is 15% of the mass of chitosan.

[0182] (3) Pour 40g of peanut skin extract / chitosan blend into a 15cm diameter disc and air dry to obtain a peanut skin extract / chitosan blend membrane.

[0183] The obtained peanut skin extract / chitosan blend membrane was subjected to performance testing, and the test results are as follows:

[0184] Figure 18 This is a photograph of the membrane prepared in Comparative Example 4. From... Figure 18 It can be seen that there are small particles on the membrane surface, and the uniformity is very poor.

[0185] Comparative Example 5

[0186] A method for preparing a peanut skin extract / chitosan blend membrane includes the following steps:

[0187] (1) Add 10g of peanut skin powder to 300mL of 50% ethanol solution and extract at 50℃ for 60min. After extraction, let stand, filter, evaporate the filtrate at 40℃ for 24h, and dry to obtain peanut skin extract.

[0188] (2) Dissolve peanut skin extract in extraction solvent and stir at 300 rpm for 2 h to fully dissolve peanut extract in water. Then add chitosan and acetic acid and stir at 600 rpm and 50°C in a water bath for 4 h to mix evenly to obtain peanut skin extract / chitosan blend (CS / PS-M-15%). The mass concentration of chitosan in water is 2%, the mass concentration of acetic acid in water is 2%, and the amount of peanut skin extract is 15% of the mass of chitosan.

[0189] (3) Pour 40g of peanut skin extract / chitosan blend into a 15cm diameter disc and air dry to obtain a peanut skin extract / chitosan blend membrane.

[0190] The obtained peanut skin extract / chitosan blend membrane was subjected to performance testing, and the test results are as follows:

[0191] Figure 19 This is a photograph of the membrane prepared in Comparative Example 5. From... Figure 19 It can be seen that there are some flocculent substances on the membrane surface, and the uniformity is very poor.

[0192] Comparative Example 6

[0193] A method for preparing a peanut skin extract / chitosan blend membrane includes the following steps:

[0194] (1) Add 10g of peanut skin powder to 300mL of 50% ethanol solution and extract at 50℃ for 60min. After extraction, let stand, filter, evaporate the filtrate at 40℃ for 24h, and dry to obtain peanut skin extract.

[0195] (2) Dissolve peanut skin extract in extraction solvent and stir at 300 rpm for 2 h to fully dissolve peanut extract in water. Then add chitosan and acetic acid and stir at 600 rpm and 50°C in a water bath for 6 h to mix evenly to obtain peanut skin extract / chitosan blend (CS / PS-M-15%). The mass concentration of chitosan in water is 2%, the mass concentration of acetic acid in water is 2%, and the amount of peanut skin extract is 15% of the mass of chitosan.

[0196] (3) Pour 40g of peanut skin extract / chitosan blend into a 15cm diameter disc and air dry it naturally. Then soak it in a 1% NaOH solution at room temperature for 30min, wash it with a large amount of deionized water until neutral, and then air dry it to obtain a peanut skin extract / chitosan blend membrane.

[0197] The obtained peanut skin extract / chitosan blend membrane was subjected to performance testing, and the test results are as follows:

[0198] Figure 20 This is a photograph of the membrane prepared in Comparative Example 6. From... Figure 20 It can be seen that the membrane is very wrinkled and brittle.

[0199] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A method for preparing peanut skin extract / chitosan blended fiber, characterized in that, Includes the following steps: Peanut skin extract / chitosan blend solution was degassed and placed in a spinning solution injection container. The fiber was propelled through a coagulation bath at a certain speed. The fiber was then appropriately drawn and wound onto a winding device for collection. The fiber was washed until it was neutral. The neutral fiber was then immersed in a glycerol solution, removed, and dried to obtain peanut skin extract / chitosan blend fiber. The preparation method of the peanut skin extract / chitosan blend includes the following steps: (1) Peanut skin powder was added to an ethanol solution with a mass concentration of 50-100% for extraction. After extraction, the mixture was allowed to stand, filtered, and the filtrate was evaporated and dried to obtain peanut skin extract. (2) Dissolve peanut skin extract in water, stir at 300 rpm for 2 hours, then add chitosan and acetic acid and mix evenly to obtain peanut skin extract / chitosan blend; The mixture was stirred at 60℃ and 600 pm for 12 hours to achieve uniform mixing; the amount of peanut skin extract used was 6-15% of the mass of chitosan, and the mass concentration of chitosan in water was 2.5%.

2. The method according to claim 1, characterized in that, The coagulation bath is a mixture of NaOH solution and ethanol, wherein the mass concentration of NaOH solution is 4-6%, the solvent is water, and the mass ratio of NaOH solution to ethanol is 2:

1.

3. The method according to claim 1, characterized in that, The glycerol solution has a volume concentration of 0.5-1.5% and uses water as the solvent.

4. The method according to claim 1, characterized in that, The winding temperature is 20-30℃, and the winding speed is 40-60 r / min.

5. The method according to claim 1, characterized in that, Degassing is performed by static degassing; the propulsion speed is 0.

4. 0.6 mL / min.

6. The peanut skin extract / chitosan blend fiber prepared by the method according to any one of claims 1 to 5.

7. A method for preparing a peanut skin extract / chitosan blend membrane, characterized in that, The peanut skin extract / chitosan blend was poured into a mold and dried to obtain a peanut skin extract / chitosan blend film. The preparation method of the peanut skin extract / chitosan blend includes the following steps: (1) Peanut skin powder was added to an ethanol solution with a mass concentration of 50-100% for extraction. After extraction, the mixture was allowed to stand, filtered, and the filtrate was evaporated and dried to obtain peanut skin extract. (2) Dissolve peanut skin extract in water, stir at 300 rpm for 2 hours, then add chitosan and acetic acid and mix evenly to obtain peanut skin extract / chitosan blend; The mixture was stirred at 50℃ and 600rpm for 6 hours to achieve uniform mixing; the amount of peanut skin extract used was 5% of the mass of chitosan, and the mass concentration of chitosan in water was 2%.

8. The peanut skin extract / chitosan blend membrane prepared by the method of claim 7.

9. The application of the peanut skin extract / chitosan blend fiber of claim 6 or the peanut skin extract / chitosan blend membrane of claim 8 in the field of antibacterial composite materials.

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