A hydrophobic PHBV composite fiber and its preparation method

Abstract

The invention relates to the technical field of composite fibers, in particular to a hydrophobic PHBV composite fiber and a preparation method thereof. Polylactic acid and PHBV are selected as composite fiber raw materials, and an ester exchange catalyst and a maleic anhydride compound are selected as a compatibilizer. Nanocellulose is prepared by crushing microcrystalline cellulose, which is then treated with sodium periodate to obtain aldehyde-modified nanocellulose. A silver ammonia solution is then added to synthesize silver-loaded nanocellulose in situ. Unsaturated double bonds are introduced into the silver-loaded nanocellulose with alkenyl succinic anhydride to obtain double-bonded silver-loaded nanocellulose. Methacrylamide, octadecyl methacrylate, double-bonded silver-loaded nanocellulose, double-bonded syringaldehyde, and hydroxyethyl methacrylate are reacted by free radical polymerization to prepare a green, healthy, fluorine-free, hydrophobic, broad-spectrum antibacterial composite nanocellulose with multiple active sites. The composite fiber is endowed with long-lasting antibacterial and hydrophobic properties, thereby improving the use range and service life of the composite fiber.

Description

Technical Field

[0001] The present invention relates to the technical field of composite fibers, in particular to a hydrophobic PHBV composite fiber and a preparation method thereof. Background Art

[0002] With the development of society and the promotion of concepts such as environmental protection and health, in the textile field, consumers' attention has gradually shifted from difficult-to-degrade chemical synthetic fibers to bio-based degradable materials. The development of degradable green composite materials is of great significance to solving environmental pollution. PHBV, the full name of which is poly (3-hydroxybutyric acid-co-3-hydroxyvaleric acid copolyester), is a degradable polymer material produced by biological fermentation. It has attracted widespread attention due to its good mechanical strength and degradability, but it also has defects such as poor thermal stability and narrow processing window, which limit its further application.

[0003] In the current market, blending is usually chosen to improve the physical and mechanical properties of composite materials. However, when applied to the textile field, there are still problems such as poor hydrophobicity and antifouling properties and limited antibacterial properties. Summary of the Invention

[0004] The object of the present invention is to provide a hydrophobic PHBV composite fiber and a preparation method thereof to solve the problems in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A method for preparing a hydrophobic PHBV composite fiber comprises the following steps:

[0007] S1: drying PHBV, polylactic acid, and composite nanocellulose, mixing PHBV, polylactic acid, composite nanocellulose, and a compatibilizer, and melt-extruding to obtain a blended masterbatch;

[0008] S2: After drying the blended masterbatch, melt spinning is performed to obtain raw yarn;

[0009] S3: The raw silk is sequentially drawn, curled, and cut to obtain a hydrophobic PHBV composite fiber.

[0010] Furthermore, the mass content ratio of PHBV to polylactic acid in the blended masterbatch is 17-27%.

[0011] Furthermore, the mass content ratio of the composite nanocellulose and polylactic acid in the blended masterbatch is 6-9%; the mass content ratio of the compatibilizer and polylactic acid in the blended masterbatch is 2-4%.

[0012] Furthermore, the working conditions of the melt extrusion are: a screw speed of 80 r / min and a working temperature of 180°C.

[0013] Furthermore, the working conditions of melt spinning are: spinning temperature of 190° C., screw speed of 45 r / min, spinneret diameter of 2 mm, and winding speed of 35 m / min.

[0014] Furthermore, the working conditions for drawing are: drawing temperature of 68-72° C., drawing ratio of 2.5-3 times, and winding speed of 190 m / min.

[0015] Furthermore, the compatibilizer is obtained by compounding the ester exchange catalyst and maleic anhydride in a mass ratio of 1:2.

[0016] Furthermore, the preparation of composite nanocellulose includes the following steps:

[0017] (1) Using an ultrasonic cell disruptor to treat microcrystalline cellulose to obtain nanocellulose; mixing nanocellulose and deionized water to prepare a nanocellulose suspension, adding sodium periodate, stirring for 22-24 hours in the dark, centrifuging, diluting with deionized water, ultrasonically dispersing, adding silver ammonia solution, ultrasonically shaking, transferring to a 38-42°C water bath and keeping warm for 10-20 minutes to obtain silver-loaded nanocellulose;

[0018] (2) Mixing silver-loaded nanocellulose and N,N-dimethylacetamide, adding hexadecyltrimethylammonium bromide and sodium carbonate, keeping warm in a water bath for 50-60 minutes, adding alkenylsuccinic anhydride, stirring for 5-6 hours, filtering, washing, soaking in hydrochloric acid for 8-10 minutes, and washing with water until neutral to obtain double-bonded silver-loaded nanocellulose;

[0019] (3) Under nitrogen atmosphere, methacrylamide, octadecyl methacrylate, double-bonded silver-loaded nanocellulose, double-bonded syringaldehyde, hydroxyethyl methacrylate, azobisisobutyronitrile, and N,N-dimethylformamide were mixed, heated to 68-72°C and kept warm for 4-6 hours, deionized water was added, and the mixture was dried to obtain composite nanocellulose.

[0020] Further, the preparation of double-bonded syringaldehyde comprises the following steps:

[0021] Under a nitrogen atmosphere, vanillin and 4-dimethylaminopyridine are mixed, methacrylic anhydride is added, the temperature is raised to 48-52°C and kept warm for 22-24 hours, 15 mL of dichloromethane is added, and the mixture is washed with a saturated aqueous sodium bicarbonate solution until there are no bubbles. The mixture is washed with an aqueous sodium hydroxide solution and an aqueous hydrochloric acid solution 1-3 times in sequence, and anhydrous magnesium sulfate is added for drying. The mixture is filtered, distilled under reduced pressure, and dried to obtain double-bonded vanillin.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention provides a hydrophobic PHBV composite fiber and a preparation method thereof. By optimizing the components and process, the hydrophobic PHBV composite fiber with high mechanical strength and good antibacterial property is prepared.

[0024] The biodegradable polymer polylactic acid is selected to be blended with PHBV to prepare the composite fiber, and an ester exchange catalyst and maleic anhydride are selected as a compatibilizer to improve the compatibility between the two. While overcoming the inherent brittleness of polylactic acid, the mechanical strength and thermal stability of PHBV are improved.

[0025] In order to give the composite fiber excellent antibacterial properties, nanosilver is introduced as an antibacterial agent in the present invention. In order to improve the uniformity of the dispersion of nanosilver in the fiber, the present invention first crushes microcrystalline cellulose to prepare nanocellulose, then treats it with sodium periodate to obtain formaldehyde-modified nanocellulose, and then adds silver ammonia solution to synthesize silver-loaded nanocellulose in situ, solving the problem of easy agglomeration of nanosilver. The silver-loaded nanocellulose is compounded with PHBV and polylactic acid, which not only plays the reinforcing role of nanocellulose but also gives the composite fiber antibacterial properties.

[0026] In order to further improve the interfacial compatibility between silver-loaded nanocellulose and composite fibers, firmly bind the silver-loaded nanocellulose to the composite fibers, and provide them with long-lasting antibacterial and hydrophobic properties, the silver-loaded nanocellulose was modified. First, unsaturated double bonds were introduced into the silver-loaded nanocellulose using alkenyl succinic anhydride to obtain double-bonded silver-loaded nanocellulose. Then, free radical polymerization was used to react methacrylamide, octadecyl methacrylate, double-bonded silver-loaded nanocellulose, double-bonded syringaldehyde, and hydroxyethyl methacrylate to prepare a green, healthy, fluorine-free, hydrophobic, broad-spectrum antibacterial composite nanocellulose with multiple active sites. The double-bonded syringaldehyde is made from biomass-based vanillin with antibacterial properties and is double-bonded by Steglich esterification. The introduction of double-bonded syringaldehyde not only synergizes with nanosilver to achieve broad-spectrum antibacterial efficacy, but also improves the bonding strength between the composite nanocellulose and the base material, thereby giving the composite fiber long-lasting antibacterial and hydrophobic properties, thereby increasing the scope of use and life of the composite fiber. DETAILED DESCRIPTION

[0027] The following will provide a clear and complete description of the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0028] It should be noted that if the embodiments of the present invention involve directional indications such as up, down, left, right, front, and back, such directional indications are only used to explain a specific posture, such as the relative position relationship between components, the movement status, etc. If the specific posture changes, the directional indication will also change accordingly. In addition, the technical solutions between the various embodiments may be combined with each other, but they must be based on the premise that they can be implemented by ordinary technicians in this field. If the combination of technical solutions is mutually inconsistent or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0029] The technical solutions of the present invention are further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely used to explain the present invention and are not intended to limit the present invention.

[0030] Example 1: A method for preparing a hydrophobic PHBV composite fiber, comprising the following steps:

[0031] S1: drying PHBV, polylactic acid, and composite nanocellulose, mixing PHBV, polylactic acid, composite nanocellulose, and a compatibilizer, and melt-extruding to obtain a blended masterbatch;

[0032] The mass content ratio of PHBV to polylactic acid in the blended masterbatch is 17%;

[0033] The mass content ratio of composite nanocellulose and polylactic acid in the blended masterbatch is 6%;

[0034] The mass content ratio of the compatibilizer and polylactic acid in the blended masterbatch is 2%;

[0035] The working conditions of melt extrusion were: screw speed 80 r / min, working temperature 180 °C;

[0036] The compatibilizer is prepared by mixing an ester exchange catalyst and maleic anhydride in a mass ratio of 1:2;

[0037] The preparation of the composite nanocellulose comprises the following steps:

[0038] (1) Microcrystalline cellulose was treated with an ultrasonic cell disruptor to obtain nanocellulose; nanocellulose and deionized water were mixed to prepare 100 mL of a nanocellulose suspension with a mass concentration of 1%, 1 g of sodium periodate was added, stirred for 22 h in the dark, centrifuged, diluted to 100 mL with deionized water, ultrasonically dispersed, 10 drops of saturated silver ammonia solution were added, ultrasonically shaken, and transferred to a 38°C water bath for 10 min to obtain silver-loaded nanocellulose;

[0039] (2) 6 g of silver-loaded nanocellulose and 50 mL of N,N-dimethylacetamide were mixed, 0.3 g of hexadecyltrimethylammonium bromide and 1.6 g of sodium carbonate were added, and the mixture was kept in a water bath for 50 min. 1.2 g of alkenylsuccinic anhydride was added, and the mixture was stirred for 5 h. The mixture was filtered and washed, and then soaked in 100 mL of 1 mol / L hydrochloric acid for 8 min and washed with water until neutral to obtain double-bonded silver-loaded nanocellulose.

[0040] (3) Under nitrogen atmosphere, 2.4 g of methacrylamide, 6.2 g of octadecyl methacrylate, 4.7 g of double-bonded silver-loaded nanocellulose, 4.1 g of double-bonded syringaldehyde, 2.6 g of hydroxyethyl methacrylate, 0.5 g of azobisisobutyronitrile, and 30 mL of N,N-dimethylformamide were mixed, heated to 68 °C and kept warm for 6 h, 50 mL of deionized water was added, and the mixture was dried to obtain composite nanocellulose;

[0041] The preparation of the double-bonded syringaldehyde comprises the following steps:

[0042] Under a nitrogen atmosphere, 9.5 g of vanillin and 0.1 g of 4-dimethylaminopyridine were mixed, 9.6 g of methacrylic anhydride was added, and the mixture was heated to 48°C and kept warm for 24 h. 15 mL of dichloromethane was added, and the mixture was washed with a saturated aqueous sodium bicarbonate solution until there were no bubbles. The mixture was washed once with an aqueous sodium hydroxide solution and then with an aqueous hydrochloric acid solution. The mixture was dried over anhydrous magnesium sulfate, filtered, distilled under reduced pressure, and dried to obtain double-bonded vanillin.

[0043] S2: After drying the blended masterbatch, melt spinning is performed to obtain raw yarn;

[0044] The working conditions of melt spinning were as follows: spinning temperature of 190 °C, screw speed of 45 r / min, spinneret diameter of 2 mm, and winding speed of 35 m / min;

[0045] S3: The raw yarn is sequentially drawn, curled, and cut to obtain a hydrophobic PHBV composite fiber; the drawing working conditions are: drawing temperature of 68°C, drawing ratio of 2.5 times, and winding speed of 190m / min.

[0046] Example 2: A method for preparing a hydrophobic PHBV composite fiber, comprising the following steps:

[0047] S1: drying PHBV, polylactic acid, and composite nanocellulose, mixing PHBV, polylactic acid, composite nanocellulose, and a compatibilizer, and melt-extruding to obtain a blended masterbatch;

[0048] The mass content ratio of PHBV to polylactic acid in the blended masterbatch is 21%;

[0049] The mass content ratio of composite nanocellulose and polylactic acid in the blended masterbatch is 7.2%;

[0050] The mass content ratio of the compatibilizer and polylactic acid in the blended masterbatch is 3%;

[0051] The working conditions of melt extrusion were: screw speed 80 r / min, working temperature 180 °C;

[0052] The compatibilizer is prepared by mixing an ester exchange catalyst and maleic anhydride in a mass ratio of 1:2;

[0053] The preparation of the composite nanocellulose comprises the following steps:

[0054] (1) Microcrystalline cellulose was treated with an ultrasonic cell disruptor to obtain nanocellulose; nanocellulose and deionized water were mixed to prepare 100 mL of a nanocellulose suspension with a mass concentration of 1%, 1 g of sodium periodate was added, stirred for 23 h in the dark, centrifuged, diluted to 100 mL with deionized water, ultrasonically dispersed, 10 drops of saturated silver ammonia solution were added, ultrasonically shaken, and transferred to a 40°C water bath for 15 min to obtain silver-loaded nanocellulose;

[0055] (2) 6 g of silver-loaded nanocellulose and 50 mL of N,N-dimethylacetamide were mixed, 0.3 g of hexadecyltrimethylammonium bromide and 1.6 g of sodium carbonate were added, and the mixture was kept in a water bath for 55 min. 1.2 g of alkenylsuccinic anhydride was added, and the mixture was stirred for 5.5 h. The mixture was filtered and washed, and then soaked in 100 mL of 1 mol / L hydrochloric acid for 9 min and washed with water until neutral to obtain double-bonded silver-loaded nanocellulose.

[0056] (3) Under nitrogen atmosphere, 2.4 g of methacrylamide, 6.2 g of octadecyl methacrylate, 4.7 g of double-bonded silver-loaded nanocellulose, 4.1 g of double-bonded syringaldehyde, 2.6 g of hydroxyethyl methacrylate, 0.5 g of azobisisobutyronitrile, and 30 mL of N,N-dimethylformamide were mixed, heated to 70 °C and kept warm for 5 h, 50 mL of deionized water was added, and the mixture was dried to obtain composite nanocellulose;

[0057] The preparation of the double-bonded syringaldehyde comprises the following steps:

[0058] Under a nitrogen atmosphere, 9.5 g of vanillin and 0.1 g of 4-dimethylaminopyridine were mixed, 9.6 g of methacrylic anhydride was added, the temperature was raised to 50°C and maintained for 23 h, 15 mL of dichloromethane was added, and the mixture was washed with a saturated aqueous sodium bicarbonate solution until there were no bubbles. The mixture was washed twice with an aqueous sodium hydroxide solution and then with an aqueous hydrochloric acid solution. The mixture was dried over anhydrous magnesium sulfate, filtered, distilled under reduced pressure, and dried to obtain double-bonded vanillin.

[0059] S2: After drying the blended masterbatch, melt spinning is performed to obtain raw yarn;

[0060] The working conditions of melt spinning were as follows: spinning temperature of 190 °C, screw speed of 45 r / min, spinneret diameter of 2 mm, and winding speed of 35 m / min;

[0061] S3: The raw yarn is sequentially drawn, curled, and cut to obtain a hydrophobic PHBV composite fiber; the drawing working conditions are: drawing temperature of 70°C, drawing ratio of 2.7 times, and winding speed of 190m / min.

[0062] Example 3: A method for preparing a hydrophobic PHBV composite fiber, comprising the following steps:

[0063] S1: drying PHBV, polylactic acid, and composite nanocellulose, mixing PHBV, polylactic acid, composite nanocellulose, and a compatibilizer, and melt-extruding to obtain a blended masterbatch;

[0064] The mass content ratio of PHBV to polylactic acid in the blended masterbatch is 27%;

[0065] The mass content ratio of composite nanocellulose and polylactic acid in the blended masterbatch is 9%;

[0066] The mass content ratio of the compatibilizer and polylactic acid in the blended masterbatch is 4%;

[0067] The working conditions of melt extrusion were: screw speed 80 r / min, working temperature 180 °C;

[0068] The compatibilizer is prepared by mixing an ester exchange catalyst and maleic anhydride in a mass ratio of 1:2;

[0069] The preparation of the composite nanocellulose comprises the following steps:

[0070] (1) Microcrystalline cellulose was treated with an ultrasonic cell disruptor to obtain nanocellulose; nanocellulose and deionized water were mixed to prepare 100 mL of a nanocellulose suspension with a mass concentration of 1%, 1 g of sodium periodate was added, stirred for 24 h in the dark, centrifuged, diluted to 100 mL with deionized water, ultrasonically dispersed, 10 drops of saturated silver ammonia solution were added, ultrasonically shaken, and transferred to a 42°C water bath for 10 min to obtain silver-loaded nanocellulose;

[0071] (2) 6 g of silver-loaded nanocellulose and 50 mL of N,N-dimethylacetamide were mixed, 0.3 g of hexadecyltrimethylammonium bromide and 1.6 g of sodium carbonate were added, and the mixture was kept in a water bath for 60 min. 1.2 g of alkenylsuccinic anhydride was added, and the mixture was stirred for 6 h. The mixture was filtered and washed, and then soaked in 100 mL of 1 mol / L hydrochloric acid for 10 min and washed with water until neutral to obtain double-bonded silver-loaded nanocellulose.

[0072] (3) Under nitrogen atmosphere, 2.4 g of methacrylamide, 6.2 g of octadecyl methacrylate, 4.7 g of double-bonded silver-loaded nanocellulose, 4.1 g of double-bonded syringaldehyde, 2.6 g of hydroxyethyl methacrylate, 0.5 g of azobisisobutyronitrile, and 30 mL of N,N-dimethylformamide were mixed, heated to 72 °C and kept warm for 4 h, 50 mL of deionized water was added, and the mixture was dried to obtain composite nanocellulose;

[0073] The preparation of the double-bonded syringaldehyde comprises the following steps:

[0074] Under a nitrogen atmosphere, 9.5 g of vanillin and 0.1 g of 4-dimethylaminopyridine were mixed, 9.6 g of methacrylic anhydride was added, the temperature was raised to 52°C and kept for 22 h, 15 mL of dichloromethane was added, and the mixture was washed with a saturated aqueous sodium bicarbonate solution until there were no bubbles. The mixture was washed three times with an aqueous sodium hydroxide solution and then with an aqueous hydrochloric acid solution. The mixture was dried over anhydrous magnesium sulfate, filtered, distilled under reduced pressure, and dried to obtain double-bonded vanillin.

[0075] S2: After drying the blended masterbatch, melt spinning is performed to obtain raw yarn;

[0076] The working conditions of melt spinning were as follows: spinning temperature of 190 °C, screw speed of 45 r / min, spinneret diameter of 2 mm, and winding speed of 35 m / min;

[0077] S3: The raw yarn is sequentially drawn, curled, and cut to obtain a hydrophobic PHBV composite fiber; the drawing working conditions are: drawing temperature of 72°C, drawing ratio of 3 times, and winding speed of 190m / min.

[0078] Comparative Example 1: Taking Example 3 as the control group, the composite nanocellulose was replaced with silver-loaded nanocellulose, and the other processes were normal.

[0079] Comparative Example 2: Example 3 was used as a control group, in which double-bonded syringaldehyde was not prepared and the other processes were normal.

[0080] Sources of raw materials used (for demonstration purposes only):

[0081] PHBVY1000P: Nanjing Hesu Times Antibacterial Materials Technology Group Co., Ltd.; Polylactic acid 032563: Hubei Shiteng Chemical Technology Co., Ltd.; Maleic anhydride (99%): Shandong Qiangsen Chemical Co., Ltd.; Silver ammonia solution JK8197: Shanghai Jingkang Bioengineering Co., Ltd.; Transesterification catalyst (zinc acetate) Z110777, microcrystalline cellulose C104844, sodium periodate S104091, N,N-dimethylacetamide D108096, hexadecyltrimethylammonium bromide C274355, alkenylsuccinic acid Anhydride (dodecenylsuccinic anhydride) D351109, methacrylamide M104042, octadecyl methacrylate S107562, hydroxyethyl methacrylate H140643, azobisisobutyronitrile A434183, N,N-dimethylformamide D111999, vanillin V100115, 4-dimethylaminopyridine D109207, methacrylic anhydride M102519: Aladdin reagent; sodium carbonate, hydrochloric acid, dichloromethane, sodium bicarbonate, sodium hydroxide, anhydrous magnesium sulfate, analytical grade: Sinopharm reagent.

[0082] Performance test: The composite fibers prepared in the examples and comparative examples were tested:

[0083] Dry elongation at break: refer to GB / T14337-2022, the working temperature is 25℃, the test is carried out using a constant-speed elongation single fiber tensile tester, the tensile speed is 50mm / min, and each sample is tested 10 times to obtain the average value;

[0084] Sample preparation: The prepared composite fiber was used to weave a single-layer plain weave fabric on a sample loom, with a warp density of 540 threads / 10cm, a weft density of 480 threads / 10cm, and a square meter weight of 105g / m 2 ;

[0085] Hydrophobicity: The prepared samples were tested for water contact angle using a tester with a 2µL deionized water droplet;

[0086] Antimicrobial persistence: Tested with reference to ATCC 100-2004, the sample was cut into pieces measuring 2.54 cm in length and width and placed on a Petri dish. 25 µL of bacterial solution was added, and the sample of the same size was placed over the sample. Gravity was applied to keep the two fabrics close together for 10 minutes. 5 mL of 0.02N sodium thiosulfate solution was added to the Petri dish. The dish was covered and vortexed, then diluted with phosphate buffer solution. The dilution was placed in culture medium and incubated at 37°C for 24 hours. The number of surviving bacteria was counted, and the corresponding antimicrobial rate was calculated. The sample was then washed 20 times with standard water before testing. ATCC 6538 Staphylococcus aureus was used as the test strain. The results are shown in Table 1.

[0087] Table 1

[0088]

[0089] The present invention provides a hydrophobic PHBV composite fiber and a preparation method thereof. By optimizing the components and process, the hydrophobic PHBV composite fiber with high mechanical strength and good antibacterial property is prepared.

[0090] Comparing Example 3 with Comparative Examples 1 and 3, it can be seen that in order to impart excellent antibacterial properties to the composite fiber, nanosilver is introduced as an antibacterial agent in the present invention. In order to improve the uniformity of dispersion of nanosilver in the fiber, the present invention first crushes microcrystalline cellulose to prepare nanocellulose, then treats it with sodium periodate to obtain formaldehyde-modified nanocellulose, and then adds a silver ammonia solution to in-situ synthesize silver-loaded nanocellulose, thereby solving the problem of easy agglomeration of nanosilver. The silver-loaded nanocellulose is composited with PHBV and polylactic acid, which not only exerts the reinforcing effect of nanocellulose but also imparts antibacterial properties to the composite fiber.

[0091] In order to further improve the interfacial compatibility between silver-loaded nanocellulose and composite fibers, firmly bind the silver-loaded nanocellulose to the composite fibers, and provide them with long-lasting antibacterial and hydrophobic properties, the silver-loaded nanocellulose was modified. First, unsaturated double bonds were introduced into the silver-loaded nanocellulose using alkenyl succinic anhydride to obtain double-bonded silver-loaded nanocellulose. Then, free radical polymerization was used to react methacrylamide, octadecyl methacrylate, double-bonded silver-loaded nanocellulose, double-bonded syringaldehyde, and hydroxyethyl methacrylate to prepare a green, healthy, fluorine-free, hydrophobic, broad-spectrum antibacterial composite nanocellulose with multiple active sites. The double-bonded syringaldehyde is made from biomass-based vanillin with antibacterial properties and is double-bonded by Steglich esterification. The introduction of double-bonded syringaldehyde not only synergizes with nanosilver to achieve broad-spectrum antibacterial efficacy, but also improves the bonding strength between the composite nanocellulose and the base material, thereby giving the composite fiber long-lasting antibacterial and hydrophobic properties, thereby increasing the service range and life of the composite fiber.

[0092] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structural transformations made using the present invention specification under the inventive concept of the present invention, or any direct / indirect application in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A method for preparing a hydrophobic PHBV composite fiber, characterized in that: The following steps are involved: S1: drying PHBV, polylactic acid, and composite nanocellulose, mixing PHBV, polylactic acid, composite nanocellulose, and a compatibilizer, and melt-extruding to obtain a blended masterbatch; S2: After drying the blended masterbatch, melt spinning is performed to obtain raw yarn; S3: The raw silk is sequentially drawn, curled, and cut to obtain a hydrophobic PHBV composite fiber; The preparation of the composite nanocellulose comprises the following steps: (1) Using an ultrasonic cell disruptor to treat microcrystalline cellulose to obtain nanocellulose; mixing nanocellulose and deionized water to prepare a nanocellulose suspension, adding sodium periodate, stirring for 22-24 hours in the dark, centrifuging, diluting with deionized water, ultrasonically dispersing, adding silver ammonia solution, ultrasonically shaking, transferring to a 38-42°C water bath and keeping warm for 10-20 minutes to obtain silver-loaded nanocellulose; (2) Mixing silver-loaded nanocellulose and N,N-dimethylacetamide, adding hexadecyltrimethylammonium bromide and sodium carbonate, keeping warm in a water bath for 50-60 minutes, adding alkenylsuccinic anhydride, stirring for 5-6 hours, filtering, washing, soaking in hydrochloric acid for 8-10 minutes, and washing with water until neutral to obtain double-bonded silver-loaded nanocellulose; (3) Under a nitrogen atmosphere, methacrylamide, octadecyl methacrylate, double-bonded silver-loaded nanocellulose, double-bonded syringaldehyde, hydroxyethyl methacrylate, azobisisobutyronitrile, and N,N-dimethylformamide were mixed, heated to 68-72°C and kept warm for 4-6 hours, deionized water was added, and the mixture was dried to obtain composite nanocellulose; The preparation of the double-bonded syringaldehyde comprises the following steps: Under a nitrogen atmosphere, vanillin and 4-dimethylaminopyridine are mixed, methacrylic anhydride is added, the temperature is raised to 48-52°C and maintained for 22-24 hours, dichloromethane is added, and the mixture is washed with a saturated aqueous sodium bicarbonate solution until there are no bubbles. The mixture is washed with an aqueous sodium hydroxide solution and an aqueous hydrochloric acid solution 1-3 times in sequence, and dried over anhydrous magnesium sulfate. The mixture is filtered, distilled under reduced pressure, and dried to obtain double-bonded vanillin. The compatibilizer is prepared by compounding an ester exchange catalyst and maleic anhydride in a mass ratio of 1:

2.

2. The method for preparing a hydrophobic PHBV composite fiber according to claim 1, characterized in that: In the blended masterbatch, the mass content ratio of PHBV and polylactic acid is 17-27%.

3. The method for preparing a hydrophobic PHBV composite fiber according to claim 1, characterized in that: In the blended masterbatch, the mass content ratio of the composite nanocellulose and the polylactic acid is 6-9%; in the blended masterbatch, the mass content ratio of the compatibilizer and the polylactic acid is 2-4%.

4. The method for preparing a hydrophobic PHBV composite fiber according to claim 1, characterized in that: The working conditions of melt extrusion are: screw speed of 80 r / min and working temperature of 180°C.

5. The method for preparing a hydrophobic PHBV composite fiber according to claim 1, characterized in that: The working conditions of melt spinning were as follows: spinning temperature of 190°C, screw speed of 45 r / min, spinneret diameter of 2 mm, and winding speed of 35 m / min.

6. The method for preparing a hydrophobic PHBV composite fiber according to claim 1, characterized in that: The working conditions for drawing are: drawing temperature of 68-72°C, drawing ratio of 2.5-3 times, and winding speed of 190m / min.

7. A hydrophobic PHBV composite fiber, characterized in that: The compound is prepared by the preparation method according to any one of claims 1 to 6.

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