Method for preparing regenerated silk fiber, regenerated silk fiber

Abstract

The present application discloses a method for preparing regenerated silk fibers and regenerated silk fibers. The method comprises: providing a silk fibroin solution; preparing a silk fibroin / calcium carbonate solution, comprising adding calcium carbonate to the silk fibroin solution; 2+ Source and CO3 2‑ source to make Ca 2+ and CO3 2‑ The calcium carbonate particles obtained by the reaction are in situ mineralized in a silk fibroin matrix to produce a silk fibroin / calcium carbonate solution; preparing spun fibers includes extruding the silk fibroin / calcium carbonate solution into an alcohol coagulation bath to produce spun fibers; and preparing regenerated silk fibers includes subjecting the spun fibers to multi-stage stretching to produce regenerated silk fibers. The regenerated silk fibers produced by the method of the present application can have extremely high strength and toughness.

Description

Technical Field

[0001] The present application belongs to the field of textiles, and specifically relates to a method for preparing regenerated silk fibers and regenerated silk fibers. Background Art

[0002] Spider silk plays an important role in the application of special materials due to its outstanding mechanical properties. However, the disadvantage of spider silk's low yield greatly limits its application.

[0003] Silk fiber is a natural fiber with excellent mechanical properties. For example, the strength of silk fiber can reach about 600MPa, the elongation at break can reach about 18%, the modulus can reach about 7GPa, and the toughness can reach 70MJ·m -3 However, the mechanical properties of silk fibers are far inferior to those of spider silk. There is an urgent need to improve natural silk to produce regenerated silk fibers with mechanical properties comparable to those of spider silk.

[0004] At present, the main methods for preparing regenerated silk fibers include wet spinning, dry spinning and microfluidic spinning. Among them, wet spinning may be one of the most suitable methods for commercialization. During the wet spinning process, the aggregation structure and orientation of the silk fibroin molecular chain can be optimized by adjusting the spinning solution or using post-stretching to improve the mechanical properties of the regenerated silk fibers. In addition, nanomaterials, such as nanospheres, nanowires and nanosheets, can be easily introduced into the silk fibroin molecular chain network, thereby changing the aggregation structure of the silk fibroin. Therefore, silk fibroin can also be modified by nanomaterials to improve the mechanical properties of the regenerated silk fibers.

[0005] However, the inherent incompatibility between nanomaterials, especially inorganic nanoparticles, and the silk fibroin matrix may lead to weak interfacial interactions, resulting in poor mechanical properties of the resulting regenerated silk fibers. Summary of the Invention

[0006] To address the above-mentioned issues, the present application provides a method for preparing regenerated silk fibers and regenerated silk fibers. This method can form a strong binding force between the silk fibroin molecular chains and the surface of the calcium carbonate particles, enhancing the interfacial interaction between the two. Therefore, due to the strong interfacial interaction between the silk fibroin matrix and the uniformly dispersed calcium carbonate particles, the regenerated silk fibers can be endowed with superb strength and toughness.

[0007] In a first aspect, the present application provides a method for preparing regenerated silk fiber, comprising:

[0008] providing a silk fibroin solution;

[0009] Prepare a silk fibroin / calcium carbonate solution, comprising adding Ca carbonate to the silk fibroin solution. 2+Source and CO3 2- source to make Ca 2 + and CO3 2- The calcium carbonate particles obtained by the reaction are in situ mineralized in the silk fibroin matrix, thereby obtaining a silk fibroin / calcium carbonate solution;

[0010] preparing nascent fibers, including extruding a silk fibroin / calcium carbonate solution into an alcohol coagulation bath to obtain nascent fibers;

[0011] The preparation of regenerated silk fibers comprises the steps of multi-stage stretching of primary fibers to obtain regenerated silk fibers.

[0012] In the method of the present application, Ca 2+ and CO3 2- The calcium carbonate particles obtained by the reaction are in situ mineralized in the silk fibroin matrix, which is beneficial to enhancing the interfacial interaction between the calcium carbonate particles and the silk fibroin matrix and improving the compatibility between the calcium carbonate particles and the silk fibroin matrix, thereby facilitating the uniform dispersion of the calcium carbonate particles in the silk fibroin solution and reducing the risk of calcium carbonate particles agglomerating in the silk fibroin matrix. During the extrusion coagulation and multi-stage stretching process of the silk fibroin / calcium carbonate solution, the calcium carbonate particles and the silk fibroin matrix can still be combined together through strong interactions. Thus, the regenerated silk fiber prepared can have extremely high strength and toughness.

[0013] In any embodiment of the present application, the silk fibroin in the silk fibroin solution is silk fibroin extracted from silk cocoons. Preferably, the silk cocoons include one or more of mulberry silk cocoons, tussah silk cocoons, and castor silk cocoons.

[0014] In any embodiment of the present application, providing a silk fibroin solution comprises:

[0015] Degumming the silk cocoons with an alkaline solution to obtain degummed silk fibers;

[0016] The degummed silk fibers are added to a LiBr solution to dissolve the degummed silk fibers, thereby obtaining a silk fibroin solution.

[0017] In any embodiment of the present application, the mass percentage of silk fibroin in the silk fibroin solution is 2-8%.

[0018] In any embodiment of the present application, preparing a silk fibroin / calcium carbonate solution comprises:

[0019] Add Ca to the silk fibroin solution 2+ Source and CO3 2- source, at 4-25℃, Ca 2+ and CO3 2- React for 0.5-2 days to allow Ca2+ and CO3 2- The calcium carbonate particles obtained by the reaction are in situ mineralized in the silk fibroin matrix, thereby obtaining a silk fibroin / calcium carbonate solution.

[0020] In any embodiment of the present application, Ca 2+ The source is selected from calcium chloride solution, calcium nitrate solution or a combination thereof, preferably, Ca 2+ Source, Ca 2+ The concentration is 0.01-0.5 mol / L; and / or

[0021] CO3 2- The source is selected from sodium carbonate solution, ammonium carbonate solution, potassium carbonate solution or a combination thereof, preferably, CO3 2- Source, CO3 2- The concentration is 0.01-0.5mol / L.

[0022] In any embodiment of the present application, based on the total mass of the silk fibroin / calcium carbonate solution, the mass percentage of calcium carbonate is 0.5-3%.

[0023] In any embodiment of the present application, the multi-stage stretching ratio is 3-10 times, preferably 6-9 times.

[0024] In any embodiment of the present application, the as-spun fiber is subjected to multi-stage stretching, comprising:

[0025] The spun fiber is stretched sequentially through the first roller, the second roller and the third roller, wherein the rotation speed of the first roller is 1.2-2.0 m / min, the rotation speed of the second roller is 3-8 m / min, and the rotation speed of the third roller is 4-19 m / min.

[0026] The second aspect of the present application provides a regenerated silk fiber prepared according to the method of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a transmission electron micrograph of the silk fibroin / calcium carbonate solution prepared in Example 1 of the present application;

[0028] Figure 2 This is the X-ray diffraction pattern of the silk fibroin / calcium carbonate prepared in Example 1 of the present application;

[0029] Figure 3 This is a Raman spectrum of the silk fibroin / calcium carbonate prepared in Example 1 of the present application;

[0030] Figure 4 This is an infrared spectrum of the silk fibroin / calcium carbonate prepared in Example 1 of the present application;

[0031] Figure 5Scanning electron micrographs of the regenerated silk fibers prepared in Examples 1-4 of the present application;

[0032] Figure 6 The stress-strain diagrams of the regenerated silk fibers prepared in Examples 1-4 of the present application;

[0033] Figure 7 A comparison chart of the strength and elongation at break of the regenerated silk fibers prepared in Examples 1-4 of the present application;

[0034] Figure 8 This is a comparison chart of the modulus and toughness of the regenerated silk fibers prepared in Examples 1-4 of the present application;

[0035] Figure 9 The stress-strain diagrams of the regenerated silk fibers prepared in Examples 1, 5-6, and Comparative Example 1 of the present application;

[0036] Figure 10 A comparison chart of the strength and elongation at break of the regenerated silk fibers prepared in Examples 1, 5-6, and Comparative Example 1 of the present application;

[0037] Figure 11 This is a comparison chart of the modulus and toughness of the regenerated silk fibers prepared in Examples 1, 5-6, and Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0038] In order to make the application purpose, technical solution and beneficial technical effects of this application clearer, the application is further described in detail below with reference to the embodiments. It should be understood that the embodiments described in this specification are only for explaining this application and are not intended to limit this application.

[0039] For simplicity, this application only explicitly discloses certain numerical ranges. However, any lower limit may be combined with any upper limit to form an unspecified range; and any lower limit may be combined with other lower limits to form an unspecified range, and similarly, any upper limit may be combined with any other upper limit to form an unspecified range. In addition, although not explicitly stated, each point or individual value between the endpoints of a range is included in the range. Thus, each point or individual value may serve as its own lower limit or upper limit and be combined with any other point or individual value, or with other lower limits or upper limits, to form an unspecified range.

[0040] In the description of this application, it should be noted that, unless otherwise specified, “above” and “below” are inclusive of the number, and “a variety” in “one or more” means two or more.

[0041] The above disclosure of the present application is not intended to describe every disclosed embodiment or every implementation in the present application. The following description more specifically illustrates exemplary embodiments. In many places throughout the application, guidance is provided through a series of examples, which can be used in various combinations. In each example, the enumeration is intended only as a representative group and should not be construed as exhaustive.

[0042] As described in the background art, the inherent incompatibility between nanomaterials, especially inorganic nanoparticles, and the silk fibroin matrix may lead to weak interfacial interactions, thereby resulting in poor mechanical properties of the resulting regenerated silk fibers.

[0043] In view of this, the inventors, after in-depth research and extensive experiments, provide a method for regenerating silk fibers and regenerated silk fibers.

[0044] In a first aspect, the present application provides a method for preparing regenerated silk fibers, comprising the following steps S10 to S40.

[0045] S10, provides a silk fibroin solution.

[0046] S20, preparing a silk fibroin / calcium carbonate solution, comprising adding Ca carbonate to the silk fibroin solution. 2+ Source and CO3 2- source to make Ca 2+ and CO3 2- The calcium carbonate particles obtained by the reaction are in situ mineralized in the silk fibroin matrix, thereby obtaining a silk fibroin / calcium carbonate solution.

[0047] In step S20, Ca 2+ Source and CO3 2- Sources may include Ca 2+ Source and CO3 2- Source, those skilled in the art can select as needed, and it is not limited here. As an example, Ca 2+ The source can be Ca 2+ aqueous solution, CO3 2- The source can include CO3 2- aqueous solution, Ca 2+ Source and CO3 2- Source, Ca 2+ and CO3 2- The concentration of can be adjusted according to the concentration of the silk fibroin solution, etc., and is not limited here.

[0048] S30, preparing spun fibers, including extruding the silk fibroin / calcium carbonate solution into an alcohol coagulation bath to obtain spun fibers.

[0049] In step S30, the silk fibroin / calcium carbonate solution is extruded into an alcohol coagulation bath. This can be achieved in a variety of ways, for example, the silk fibroin / calcium carbonate solution can be extruded into an alcohol coagulation bath by a syringe. The type of alcohol coagulation bath is not specifically limited and can be selected from alcohol coagulation baths well known in the art. As an example, the alcohol coagulation bath can include a methanol coagulation bath, an ethanol coagulation bath, or a mixed coagulation bath of methanol and ethanol.

[0050] S40, preparing regenerated silk fibers, including performing multi-stage stretching on the spun fibers to obtain regenerated silk fibers.

[0051] In the method of the present application, Ca 2+ and CO3 2- The calcium carbonate particles obtained by the reaction are in situ mineralized in the silk fibroin matrix, which is beneficial to enhancing the interfacial interaction between the calcium carbonate particles and the silk fibroin matrix and improving the compatibility between the calcium carbonate particles and the silk fibroin matrix, thereby facilitating the uniform dispersion of the calcium carbonate particles in the silk fibroin solution and reducing the risk of calcium carbonate particles agglomerating in the silk fibroin matrix. During the extrusion coagulation and multi-stage stretching process of the silk fibroin / calcium carbonate solution, the calcium carbonate particles and the silk fibroin matrix can still be combined together through strong interactions. Thus, the regenerated silk fiber prepared can have extremely high strength and toughness.

[0052] In some embodiments, the fibroin solution may be a regenerated fibroin solution. The fibroin in the fibroin solution may be fibroin extracted from silkworm cocoons. Preferably, the silkworm cocoons may include one or more of mulberry silkworm cocoons, tussah silkworm cocoons, and castor silkworm cocoons.

[0053] In some embodiments, providing the silk fibroin solution may specifically include the following steps S11 to S12.

[0054] S11, degumming the silk cocoons with an alkaline solution to obtain degummed silk fibers.

[0055] In step S11, the alkaline solution may include an aqueous solution of one or more substances selected from the group consisting of sodium carbonate, potassium carbonate, and sodium bicarbonate. In the alkaline solution, the mass percentage of the solute may be 0.1-1.2%. In one embodiment, the cocoons may be added to the boiling alkaline solution and boiled 1-3 times to degummed the cocoons. The degummed cocoons are then placed in distilled water, soaked, rinsed, and dried to obtain degummed silk fibers. Preferably, based on the total mass of the alkaline solution and the cocoons, the mass percentage of the silk fibers may be 1% to 5%.

[0056] S12, adding the degummed silk fibers into the LiBr solution to dissolve the degummed silk fibers, thereby obtaining a silk fibroin solution.

[0057] In one embodiment, step S12 may include: immersing 3-8 g of degummed silk fibers in an 8-15 mol / L LiBr solution, transferring the solution to a drying oven at 50-70° C., and placing the solution for 4-10 hours to dissolve the degummed silk fibers, and purifying the solution to obtain a silk fibroin solution having a silk fibroin content of 2-8% by weight. Preferably, the purification method may be dialysis purification, and the purification may include dialyzing the regenerated silk fibroin solution in distilled water, wherein the molecular weight cutoff of the dialysis bag is 1000 Da to 5000 Da, and the dialysis time is 24 hours to 72 hours.

[0058] In some embodiments, the silk fibroin solution may contain 2-8% by weight of silk fibroin.

[0059] In some embodiments, preparing a silk fibroin / calcium carbonate solution may include:

[0060] Add Ca to the silk fibroin solution 2+ Source and CO3 2- source, at 4-25℃, Ca 2+ and CO3 2- React for 0.5-2 days to allow Ca 2+ and CO3 2- The calcium carbonate particles obtained by the reaction are in situ mineralized in the silk fibroin matrix, thereby obtaining a silk fibroin / calcium carbonate solution.

[0061] In some embodiments, Ca 2+ The source can be selected from calcium chloride solution, calcium nitrate solution or a combination thereof. 2+ Source, Ca 2+ The concentration is 0.01-0.5mol / L.

[0062] In some embodiments, CO3 2- The source can be selected from sodium carbonate solution, ammonium carbonate solution, potassium carbonate solution or a combination thereof. Preferably, CO3 2- Source, CO3 2- The concentration is 0.01-0.5mol / L.

[0063] In some embodiments, the mass percentage of calcium carbonate can be 0.5-3% based on the total mass of the silk fibroin / calcium carbonate solution.

[0064] In some embodiments, the multi-stage stretching ratio may be 3-10 times. Preferably, the multi-stage stretching ratio may be 6-9 times.

[0065] The multiple of multi-stage stretching can be achieved by adjusting the speed difference between the rollers. In some embodiments, the multi-stage stretching of the as-spun fiber may specifically include:

[0066] The spun fiber is stretched sequentially through the first roller, the second roller and the third roller, wherein the rotation speed of the first roller is 1.2-2.0 m / min, the rotation speed of the second roller is 3-8 m / min, and the rotation speed of the third roller is 4-19 m / min.

[0067] The second aspect of the present application provides a regenerated silk fiber prepared according to the method of the first aspect.

[0068] Example

[0069] The following examples more particularly describe the present disclosure, and these examples are intended to be illustrative only, as various modifications and variations within the scope of the present disclosure will be apparent to those skilled in the art. Unless otherwise indicated, all parts, percentages, and ratios reported in the following examples are by weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods and used directly without further processing, and all instruments used in the examples are commercially available.

[0070] Example 1

[0071] (1) 6 mL of 10 mmol / L CaCl2 solution and 6 mL of 10 mmol / L (NH4)2CO3 solution were added to the regenerated silk fibroin solution in sequence, and the mixture was kept warm at 4°C for 1 day to obtain a silk fibroin / calcium carbonate solution with a calcium carbonate mass percentage of 1.5%.

[0072] (2) The silk fibroin / calcium carbonate solution was extruded through a syringe into a methanol coagulation bath and stretched in 9-fold stages to obtain ultra-strong and ultra-tough regenerated silk fibers. The rotational speed of the first roller was 1.95 m / min, the rotational speed of the second roller was 4.01 m / min, and the rotational speed of the third roller was 17.64 m / min.

[0073] Example 2

[0074] (1) 3 mL of 10 mmol / L CaCl2 solution and 3 mL of 10 mmol / L (NH4)2CO3 solution were added to the regenerated silk fibroin solution in sequence, and the mixture was kept warm at 4°C for 1 day to obtain a silk fibroin / calcium carbonate solution with a calcium carbonate mass percentage of 0.5%.

[0075] (2) The silk fibroin / calcium carbonate solution was extruded into a methanol coagulation bath through a syringe and stretched in 9-fold multi-stages to obtain ultra-strong and ultra-tough regenerated silk fibers. The rotational speed of the first roller was 1.95 m / min, the rotational speed of the second roller was 4.01 m / min, and the rotational speed of the third roller was 17.64 m / min.

[0076] Example 3

[0077] (1) 4 mL of 10 mmol / L CaCl2 solution and 10 mmol / L (NH4)2CO3 solution were added to the regenerated silk fibroin solution in sequence, and the solution was kept at 4°C for 1 day to obtain a silk fibroin / calcium carbonate solution with a calcium carbonate mass percentage of 1.0%.

[0078] (2) The silk fibroin / calcium carbonate solution was extruded into a methanol coagulation bath through a syringe and stretched in 9-fold multi-stages to obtain ultra-strong and ultra-tough regenerated silk fibers. The rotational speed of the first roller was 1.95 m / min, the rotational speed of the second roller was 4.01 m / min, and the rotational speed of the third roller was 17.64 m / min.

[0079] Example 4

[0080] (1) 8 mL of 10 mmol / L CaCl2 solution and 8 mL of 10 mmol / L (NH4)2CO3 solution were added to the regenerated silk fibroin solution in sequence, and the mixture was kept warm at 4°C for 1 day to obtain a silk fibroin / calcium carbonate solution with a calcium carbonate mass percentage of 2.0%.

[0081] (2) The silk fibroin / calcium carbonate solution was extruded into a methanol coagulation bath through a syringe and stretched in 9-fold multi-stages to obtain ultra-strong and ultra-tough regenerated silk fibers. The rotational speed of the first roller was 1.95 m / min, the rotational speed of the second roller was 4.01 m / min, and the rotational speed of the third roller was 17.64 m / min.

[0082] The silk fibroin / calcium carbonate solution prepared in Example 1 was characterized by transmission electron microscopy (TEM), and the obtained TEM image was as follows: Figure 1 As shown. Figure 1 It can be seen that calcium carbonate particles can be uniformly dispersed in the silk fibroin / calcium carbonate solution. Figure 2-4 The X-ray diffraction pattern, Raman spectrum and infrared spectrum of the silk fibroin / calcium carbonate solution prepared in Example 1 are shown respectively. Figure 2-4 It can be seen that the silk fibroin / calcium carbonate solution has a diffraction peak corresponding to calcite-type calcium carbonate at a diffraction angle of 27.1°. -1 The Raman peak and 875cm -1 The Fourier transform infrared peak also confirms the presence of calcium carbonate particles. In addition, the infrared spectrum results show that the secondary structure of silk fibroin basically remains in a random coil state, indicating that the addition of calcium carbonate particles has no effect on the microstructure of the silk fibroin network.

[0083] The regenerated silk fibers prepared in Examples 1-4 were characterized by scanning electron microscopy (SEM), and the obtained SEM images are shown in FIG. Figure 5 As shown. Figure 5 It can be seen that the diameter of the regenerated silk fibers prepared in Examples 1-4 is relatively uniform and the surface is smooth. The mechanical properties of the regenerated silk fibers prepared in Examples 1-4 were tested, and the test results are as follows: Figure 6-8 shown. Figure 6-8 The stress-strain curves, strength-to-break elongation comparison graphs, and modulus-to-toughness comparison graphs of the regenerated silk fibers of Examples 1-4 are shown respectively. Figure 6-8 It can be seen that calcium carbonate can improve the mechanical properties of regenerated silk fibers, and the content of calcium carbonate has a strong correlation with the mechanical properties of regenerated silk fibers. As the content of calcium carbonate particles increases from 0.5% to 1.5%, the strength and stiffness of the regenerated silk fibers are significantly improved. However, when the content of calcium carbonate particles increases to 2.0%, the strength and stiffness of the regenerated silk fibers decrease, indicating that excessive calcium carbonate particle content may lead to poor mechanical properties of the regenerated silk fibers. Calcium carbonate particles also affect the toughness and elongation at break of regenerated silk fibers. As the content of calcium carbonate particles increases, the toughness and elongation at break of the regenerated silk fibers also show a trend of first increasing and then decreasing.

[0084] Example 5

[0085] (1) 6 mL of 10 mmol / L CaCl2 solution and 6 mL of 10 mmol / L (NH4)2CO3 solution were added to the regenerated silk fibroin solution in sequence, and the mixture was kept warm at 4°C for 1 day to obtain a silk fibroin / calcium carbonate solution with a calcium carbonate mass percentage of 1.5%.

[0086] (2) The silk fibroin / calcium carbonate solution was added to a syringe and extruded into a methanol coagulation bath, and then stretched by 3 times in multiple stages to obtain ultra-strong and ultra-tough regenerated silk fibers. The rotational speed of the first roller was 1.49 m / min, the rotational speed of the second roller was 3.1 m / min, and the rotational speed of the third roller was 4.47 m / min.

[0087] Example 6

[0088] (1) 6 mL of 10 mmol / L CaCl2 solution and 10 mmol / L (NH4)2CO3 solution were added to the regenerated silk fibroin solution in sequence, and the solution was kept at 4°C for 1 day to obtain a silk fibroin / calcium carbonate solution with a calcium carbonate mass percentage of 1.5%.

[0089] (2) The silk fibroin / calcium carbonate solution was extruded into a methanol coagulation bath through a syringe and stretched in multiple stages to obtain ultra-strong and ultra-tough regenerated silk fibers. The rotational speed of the first roller was 1.75 m / min, the rotational speed of the second roller was 5.51 m / min, and the rotational speed of the third roller was 10.51 m / min.

[0090] Comparative Example 1

[0091] (1) 6 mL of 10 mmol / L CaCl2 solution and 6 mL of 10 mmol / L (NH4)2CO3 solution were added to the regenerated silk fibroin solution in sequence, and the mixture was kept warm at 4°C for 1 day to obtain a silk fibroin / calcium carbonate solution with a calcium carbonate mass percentage of 1.5%.

[0092] (2) The silk fibroin / calcium carbonate solution is extruded into a methanol coagulation bath through a syringe without multi-stage stretching to obtain regenerated silk fibers.

[0093] The mechanical properties of Examples 1, 5-6 and Comparative Example 1 were tested, and the test results were as follows: Figure 9-11 As shown. Combined Figure 9-11 It can be seen that the stretching process in wet spinning also has a great influence on improving the mechanical properties of regenerated silk fibers. The tensile strength and modulus of the regenerated silk fibers obtained in Example 1 are much higher than those obtained in Comparative Example 1 without multi-stage stretching. This phenomenon can be attributed to the fact that multi-stage stretching can make the fibroin molecular segments in the regenerated silk fibers tightly arranged along the fiber axis. In addition, it can be seen from Examples 1, 5-6 that with the increase of the stretching ratio, the tensile strength, modulus and toughness of the regenerated silk fibers all increase. However, with the increase of the stretching ratio, the elongation at break of the regenerated silk fibers gradually decreases, which is due to the deterioration of the partial deformation ability of the fibroin molecular segments. Therefore, the stretching ratio can be reasonably controlled according to the performance requirements of the regenerated silk fibers.

[0094] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present application, and such modifications or substitutions are intended to be included within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be subject to the scope of protection of the claims.

Claims

1. A method for preparing regenerated silk fiber, characterized in that: include: providing a silk fibroin solution; Prepare a silk fibroin / calcium carbonate solution, comprising adding Ca 2+ Source and CO3 2- source, at 4-25℃, Ca 2+ and CO3 2- React for 0.5-2 days to allow Ca 2+ and CO3 2- The calcium carbonate particles obtained by the reaction are in situ mineralized in the silk fibroin matrix, thereby obtaining the silk fibroin / calcium carbonate solution; preparing nascent fibers, comprising extruding the silk fibroin / calcium carbonate solution into an alcohol coagulation bath to obtain nascent fibers; preparing regenerated silk fibers, comprising subjecting the nascent fibers to multi-stage stretching to obtain regenerated silk fibers; Based on the total mass of the silk fibroin / calcium carbonate solution, the mass percentage of calcium carbonate is 0.5-1.5%.

2. The method according to claim 1, characterized in that in, The silk fibroin in the silk fibroin solution is silk fibroin extracted from silk cocoons.

3. The method according to claim 2, characterized in that The silk cocoons include one or more of mulberry silk cocoons, tussah silk cocoons, and castor silk cocoons.

4. The method according to claim 2, characterized in that in, Providing the silk fibroin solution comprises: Degumming the silk cocoons with an alkaline solution to obtain degummed silk fibers; The degummed silk fibers are added to a LiBr solution to dissolve the degummed silk fibers, thereby obtaining the silk fibroin solution.

5. The method according to claim 1, wherein in, In the silk fibroin solution, the mass percentage of silk fibroin is 2-8%.

6. The method according to claim 1, wherein in, The Ca 2+ The source is selected from calcium chloride solution, calcium nitrate solution or a combination thereof, and / or, The CO3 2- The source is selected from sodium carbonate solution, ammonium carbonate solution, potassium carbonate solution or a combination thereof.

7. The method according to claim 1, characterized in that The Ca 2+ Source, Ca 2+ The concentration is 0.01-0.5 mol / L; and / or, The CO3 2- Source, CO3 2- The concentration is 0.01-0.5mol / L.

8. The method according to claim 1, characterized in that in, The multi-stage stretching ratio is 3-10 times.

9. The method according to claim 1, characterized in that in, The multi-stage stretching ratio is 6-9 times.

10. The method according to claim 8, characterized in that in, The multi-stage stretching of the as-spun fiber comprises: The spun fiber is stretched sequentially through a first roller, a second roller and a third roller, wherein the rotation speed of the first roller is 1.2-2.0 m / min, the rotation speed of the second roller is 3-8 m / min, and the rotation speed of the third roller is 4-19 m / min.

11. A regenerated silk fiber prepared according to the method of any one of claims 1 to 10.

Images