A regenerated protein composite fiber and its preparation method

Abstract

This invention provides a regenerated protein composite fiber and its preparation method, comprising: Step 1, treating regenerated keratin and regenerated globulin separately with denaturing solutions to obtain denatured proteins; Step 2, mixing the denatured keratin solution and the denatured globulin solution and aging the mixture to obtain a protein composite solution; Step 3, wet spinning the protein composite solution to obtain the regenerated protein composite fiber. This invention introduces denatured and expanded regenerated globulin into the keratin spinning system, and directly introduces a hydrogen peroxide bath and a stretching process during the preparation of the protein composite fiber, optimizing the high-strength and high-toughness mechanical properties, excellent redox mechanical reversibility, and good cell compatibility of the obtained regenerated keratin / globulin composite fiber.

Description

Technical Field

[0001] This invention relates to the field of biotextile technology, specifically to a regenerated protein composite fiber and its preparation method. Background Technology

[0002] High-performance bio-fiber materials, as advanced renewable and sustainable resources, often possess advantages such as low density, high mechanical strength, excellent ductility, biodegradability, and good biocompatibility, showing broad application prospects in textiles, artificial tendons, surgical sutures, and tissue engineering scaffolds. However, high tensile strength and high toughness in fiber materials are often conflicting and cannot be achieved simultaneously. Natural fibers can resolve this contradiction; for example, Nephila edulis spider silk possesses high strength (1.1 GPa) and high modulus (10 GPa) while also exhibiting high toughness (160 MJ / m). -3 This makes it a highly sought-after "super fiber." However, large-scale production of spider silk is difficult. On the one hand, spiders are difficult to breed on a large scale, resulting in insufficient supply. On the other hand, the preparation of recombinant spider silk fibers based on genetic engineering technology also faces limitations such as complex production processes, high costs, and low yields. Therefore, at present, it remains difficult to achieve the preparation of high-performance protein fibers, whether natural or recombinant.

[0003] Keratin, the main component of wool, hair, nails, hooves, feathers, and horns, is one of the richest and most underutilized protein sources, possessing excellent mechanical properties. Globally, over 2.5 million tons of wool are produced annually, but some low-grade wool and scraps from slaughterhouses cannot be used in the wool industry and ultimately become waste. On the other hand, over 65 million tons of feathers are produced worldwide, with many byproducts typically disposed of through incineration or landfill. Extracting recycled keratin from these industrial wastes for the preparation of high-performance regenerated bio-fiber materials has significant industrial value. Currently, research on regenerated keratin fibers, both domestically and internationally, is still in the basic research stage, focusing on enhancing the mechanical properties of regenerated keratin fiber monofilaments.

[0004] Professor Yang Yiqi's research group at Jiangnan University prepared regenerated keratin fibers with a tensile strength of 160 MPa and an elongation at break of 14% by modifying keratin materials (Waste Manage, 2020, 115, 65-73). Chinese invention patent (publication number: CN 116334772 A) provides a method for reinforcing wool keratin fibers by re-bonding dithiol chains, achieving a tensile strength of 186 MPa, but with an elongation of less than 10%. Additionally, invention patent (publication number: CN 117661136 A) combines wool keratin with graphene to prepare composite fibers with a tensile strength of 215 MPa and an elongation of 8.8%.

[0005] Comparative analysis revealed that while these inventions and research efforts improved the mechanical strength of regenerated keratin fibers, their overall extensibility remained low, and their toughness was significantly insufficient. Therefore, preparing biomass fibers with both high strength and high toughness, primarily based on regenerated keratin, remains a significant challenge. Summary of the Invention

[0006] This invention addresses the problem of insufficient toughness and extensibility of keratin fibers by providing a method for preparing regenerated protein composite fibers. Through wet spinning of a composite solution of keratin and globulin, regenerated protein fibers with high strength, high extensibility, high toughness, stable mechanical properties, and repairability are obtained.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing regenerated protein composite fibers includes the following steps:

[0009] Step 1: Regenerated keratin and regenerated globulin are treated with denaturing solutions to obtain denatured proteins;

[0010] Step 2: Mix the denatured keratin solution and the denatured globulin solution and then age them to obtain a protein complex solution;

[0011] Step 3: Wet spinning of the protein composite solution to obtain the regenerated protein composite fiber.

[0012] In this invention, denatured keratin and globulin can maximize the unfolding of molecular chains and enhance the entanglement between protein chains. In wet spinning, disulfide bonds are cross-linked by hydrogen peroxide to retain the entanglement. By controlling the protein ratio to optimize the secondary structure of the composite fiber, the resulting regenerated protein composite fiber has high strength and toughness and stable mechanical properties. At the same time, based on the disulfide bond cross-linking network, the composite fiber can exhibit the property of mechanical weakness during reduction and mechanical recovery during re-oxidation.

[0013] The regenerated keratin includes at least one of wool keratin, feather keratin, hair keratin, and hoof keratin.

[0014] Regenerated globulins include at least one of bovine serum albumin, horse serum albumin, rabbit serum albumin, ovalbumin, porcine serum albumin, rat serum albumin, β-lactoglobulin, regenerated soybean protein, and regenerated sericin.

[0015] The denaturing solution comprises a solvent, a reducing agent, and water; the molar concentration of the solvent in the denaturing solution is 6-10 mol / L; and the molar concentration of the reducing agent is 0.01-0.5 mol / L.

[0016] The solvent includes urea and / or guanidine hydrochloride.

[0017] The reducing agent includes one or more of dithiothreitol, β-mercaptoethanol, cysteine, reduced glutathione, mercaptoacetic acid, sodium mercaptoacetate, sodium sulfide, sodium sulfite, and tris(2-carbonylethyl)phosphohydrochloride.

[0018] In step 2, the mass ratio of denatured keratin to denatured globulin is 4:1 to 1:4. This invention regulates the ratio of these two proteins to optimize the balance between rigid structures (β-sheets and α-helices) and flexible structures (random coils) within the composite fiber, thereby optimizing the strength and toughness of the composite fiber. Preferably, the mass ratio of denatured keratin to denatured globulin in step 2 is 3:2 to 2:3.

[0019] In step 2, the mass concentration of the denatured keratin solution or denatured globulin solution is 100-300 mg / L; in this invention, a high concentration of protein solution is used for compounding to increase the viscosity of the compound solution and enhance its spinnability.

[0020] In step 2, the aging time is 5 minutes to 4 hours. Preferably, the aging time is 1 to 3 hours, and further optimized to 2 hours.

[0021] The coagulation bath for wet spinning comprises 60-80% v / v ethanol or methanol, 1-2% v / v hydrogen peroxide and water; or, the coagulation bath for wet spinning comprises 50-70% v / v ethanol or methanol, 1-2% v / v hydrogen peroxide, 10-30% v / v acetic acid and water.

[0022] Preferably, the pH of the coagulation bath is 1-3.

[0023] In this invention, hydrogen peroxide is placed in a coagulation bath to cause oxidative cross-linking of the extruded protein solution, preserving the entanglement between protein chains and ensuring that the protein does not completely refold, resulting in high strength but low toughness.

[0024] In step 3, the extrusion speed of wet spinning is 5-50 μL / min; the draw ratio λ is 1.0-5.0. Preferably, the draw ratio is 2-3.

[0025] Preferably, in step 3, the protein complex solution is extruded by the injection pump at a rate of 5-50 μL / min.

[0026] In this invention, the extrusion speed of the composite solution is related to the shear force on the protein molecules. If the speed is too low, the shear force is small, which leads to the clogging of the spinneret. If the speed is too high, the solution is easily extruded and turbulent, the protein is dispersed and cannot form fibers.

[0027] Preferably, in step 3, the protein composite solution is extruded through a long metal needle into a coagulation bath to achieve wet spinning, and the recycled protein composite fiber is obtained by collecting it through a roller.

[0028] The metal needle has an inner diameter of 0.15-0.60 mm, an outer diameter of 0.30-1.00 mm, and a length of 20-100 mm; the roller collection speed is 2-10 m / min.

[0029] After reduction and subsequent soaking in hydrogen peroxide, the mechanical properties of the regenerated protein fiber can be almost 100% restored.

[0030] This invention also provides a regenerated protein composite fiber prepared by the aforementioned method, wherein the regenerated protein composite fiber has a tensile strength ≥50MPa and a toughness ≥30MJ / m. 3 The elongation at break is ≥35%. Preferably, the regenerated protein composite fiber has a breaking strength ≥100MPa and a toughness ≥50MJ / m. 3 Elongation at break ≥40%.

[0031] Under optimal conditions, the regenerated protein composite fiber can achieve a tensile strength ≥200MPa and a toughness ≥70MJ / m. 3 .

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) In this invention, keratin and globulin are denatured and then compounded, and then wet-spun to obtain regenerated protein fibers with high mechanical strength, good toughness and strong extensibility.

[0034] (2) The regenerated protein composite fiber of the present invention can restore its mechanical properties and achieve a regeneration effect after being damaged by hydrogen peroxide soaking.

[0035] (3) The method for preparing regenerated protein composite fiber of the present invention is simple, conducive to industrial production and promotion, and promotes the further development of biomass fiber. Attached Figure Description

[0036] Figure 1 The images show electron micrographs of protein fibers in Comparative Example 1 and their formation in a hydrogen peroxide coagulation bath.

[0037] Figure 2 The large amount of keratin fibers collected by wet spinning for Comparative Example 2.

[0038] Figure 3 This is a scanning electron microscope image of pure keratin fibers in Comparative Example 2.

[0039] Figure 4 The tensile mechanical property curves of pure keratin fiber for Comparative Example 2 are shown.

[0040] Figure 5 The image is a fiber scanning electron microscope image of a keratin / globulin 4:1 composite with a stretching ratio of 1.0 in Example 1.

[0041] Figure 6 The tensile mechanical property curves of the fiber with a keratin / globulin composite of 4:1 and a stretch ratio of 1.0 in Example 1 are shown.

[0042] Figure 7 The image shows a fiber scanning electron microscope image of a keratin / globulin 3:2 composite with a stretching ratio of 1.0 in Example 2.

[0043] Figure 8 The graph shows the tensile mechanical properties of the fiber with a keratin / globulin composite of 3:2 and a stretch ratio of 1.0 in Example 2.

[0044] Figure 9 This is a scanning electron microscope image of the pure globulin composite fibers in Comparative Example 3.

[0045] Figure 10 The tensile mechanical property curves of the pure globulin composite fiber in Comparative Example 3 are shown.

[0046] Figure 11 The image is a fiber scanning electron microscope image of the keratin / globulin 3:2 composite with a stretching ratio of 3.0 in Example 3.

[0047] Figure 12 The mechanical property curves of the fiber with a keratin / globulin composite of 3:2 and a stretch ratio of 3.0 in Example 3 are shown.

[0048] Figure 13 The fiber cyclic tensile mechanical curve for Example 3 is a keratin / globulin composite with a stretch ratio of 3.0.

[0049] Figure 14 The mechanical reversibility curve of the keratin / globulin composite fiber in Example 4 is shown.

[0050] Figure 15 Cell compatibility of the keratin / globulin composite fiber in Example 5. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Modifications or equivalent substitutions made by those skilled in the art based on their understanding of the technical solutions of this invention, without departing from the spirit and scope of the invention, should be covered within the protection scope of this invention.

[0052] All raw materials used in the following specific implementation methods were purchased from the market.

[0053] Comparative Example 1

[0054] Step 1: Select keratin as regenerated wool keratin, extract keratin from wool by reduction method, and obtain regenerated wool keratin powder by dialysis freeze drying;

[0055] Step 2: Select the denaturant system: 8 mol / L urea, 0.1 mol / L dithiothreitol (DTT), weigh 400 mg of keratin powder, dissolve it in 2 ml of the above denaturant solution, dissolve at 90 degrees Celsius for 1 hour, and obtain a 200 mg / ml keratin solution with chain expansion.

[0056] Step 3: Select the coagulation bath solution as: 70% ethanol, 30% water, and adjust the pH to 1.0 using 12 mol / L hydrochloric acid;

[0057] Step 4: Select a metal long needle with an inner diameter of 0.200 mm, an outer diameter of 0.600 mm, and a length of 100 mm; use a syringe pump to inject the keratin solution through the long needle into the coagulation bath solution. The result is as follows. Figure 1 As shown, although the protein solution can gel in this coagulation bath, the resulting gel fibers are weak due to the lack of oxidative cross-linking. They are difficult to pick up with tweezers to form continuous fibers and cannot be collected, indicating that the oxidizing effect of hydrogen peroxide is essential in this spinning system.

[0058] Comparative Example 2

[0059] Step 1: Select keratin as regenerated wool keratin, extract keratin from wool by reduction method, and obtain regenerated wool keratin powder by dialysis freeze drying;

[0060] Step 2: Select the denaturant system: 8 mol / L urea, 0.1 mol / L dithiothreitol (DTT), weigh 400 mg of keratin powder, dissolve it in 2 ml of the above denaturant solution, dissolve at 90 degrees Celsius for 1 hour, and obtain a 200 mg / ml keratin solution with chain expansion.

[0061] Step 3: Select the coagulation bath solution as follows: 70% ethanol, 1% hydrogen peroxide, 30% water, and adjust the pH to 1.0 using 12 mol / L hydrochloric acid;

[0062] Step 4: Select a metal long needle with an inner diameter of 0.200 mm, an outer diameter of 0.600 mm, and a length of 100 mm. Use an injection pump to squeeze the keratin solution into the coagulation bath solution through the long needle at a speed of 10 μL / min. The protein solution is converted into fibers in the coagulation bath and collected by a rotating drum at a collection rate of 5 m / min. At this point, the stretch ratio λ is 1.0. Let the collected fibers dry at room temperature for 2 hours.

[0063] Through the above steps, continuous keratin fibers can be prepared, such as... Figure 2 As shown; scanning electron microscopy characterization revealed that the fiber diameter is approximately ~25 micrometers, such as Figure 3 As shown in the figure; tensile tests revealed that the tensile strength of the obtained keratin fibers was 36.1 ± 5.6 MPa, and the toughness was 10.4 ± 2.5 MJ / m. 3 The tensile ductility is 46.3±9.4%, such as... Figure 4 As shown, the improved extensibility is due to the chain entanglement effect. Compared with the less than 20% extensibility of conventional regenerated keratin fibers, the process of adding hydrogen peroxide to the coagulation bath solution has certain advantages.

[0064] Example 1

[0065] Step 1: Select keratin as regenerated wool keratin, extract keratin from wool by reduction method, and obtain regenerated wool keratin powder by dialysis freeze drying;

[0066] Step 2: Select the denaturant system: 8 mol / L urea, 0.1 mol / L dithiothreitol (DTT), weigh 400 mg of keratin powder, dissolve it in 2 ml of the above denaturant solution, dissolve at 90 degrees Celsius for 1 hour, and obtain a 200 mg / ml keratin solution with chain expansion.

[0067] Step 3: Weigh 400 mg of commercial bovine serum albumin (BSA) powder, dissolve it in 2 ml of the above denaturant solution, dissolve at 25 degrees Celsius for 1 hour, and obtain a 200 mg / ml bovine serum albumin solution with expanded chains.

[0068] Step 4: Mix the keratin solution and BSA solution at a volume ratio of 4:1, shake well with a shaker, and then age at room temperature for 2 hours.

[0069] Step 5: Select the coagulation bath solution as follows: 70% ethanol, 1% hydrogen peroxide, 30% water, and adjust the pH to 1.0 using 12 mol / L hydrochloric acid;

[0070] Step 6: Select a metal long needle with an inner diameter of 0.200 mm, an outer diameter of 0.600 mm, and a length of 100 mm. Use an injection pump to squeeze the aged protein composite solution into the coagulation bath solution through the long needle at a speed of 10 μL / min. The protein solution is converted into fibers in the coagulation bath and collected by a rotating drum at a collection rate of 5 m / min. At this point, the stretch ratio λ is 1.0. Let the collected fibers dry at room temperature for 2 hours.

[0071] Following the above steps, continuous keratin / BSA composite fibers can be prepared. Scanning electron microscopy characterization shows that the composite fibers have a smooth surface and a fiber diameter of approximately ~25 micrometers. Figure 5As shown; through tensile testing, it can be seen that, as Figure 6 As shown, the obtained keratin / BSA composite fiber has a tensile strength of 56.1±5.4 MPa, a high elongation of 84.6±5.4%, and a corresponding toughness of approximately 35.7±6.2 MJ / m. 3 The composite fiber exhibits significantly improved strength and toughness compared to the pure keratin fiber in Comparative Example 1. This is mainly due to the introduction of bovine serum albumin into the composite fiber system. After denaturation and unfolding of the protein chains, it enhances the chain entanglement in the protein composite system, thus resulting in higher strength and toughness.

[0072] Example 2

[0073] Following the process of Example 1, by adjusting the volume ratio of keratin and globulin in step 4 to 3:2, continuous keratin / BSA (3:2) composite fibers can be prepared. Scanning electron microscopy characterization shows that the composite fibers have a smooth surface and uniform size, with a fiber diameter of approximately ~25 micrometers. Figure 7 As shown; through tensile testing, it can be seen that, as Figure 8 As shown, the tensile strength of the obtained keratin / BSA composite fiber is approximately 119.2 ± 13.3 MPa, while the ductility is as high as 105.2 ± 6.1%, and the corresponding toughness is approximately 98.8 ± 10.8 MJ / m. 3 .

[0074] The composite fiber exhibits significantly improved strength and toughness compared to the pure keratin fiber in Comparative Example 1. This is primarily due to the introduction of bovine serum albumin into the composite fiber system. After denaturation and unfolding of the protein chains, the chain entanglement within the protein composite system is enhanced, resulting in higher strength and toughness. Compared to the composite fiber obtained in Example 1 (keratin to globulin volume ratio of 3:2), the mechanical strength and toughness of this example are further improved. This is mainly attributed to the optimal ratio of secondary structures within the keratin-globulin composite fiber under this ratio, thus achieving both high strength and high toughness simultaneously.

[0075] Comparative Example 3

[0076] Step 1: Select the denaturant system: 8 mol / L urea, 0.1 mol / L dithiothreitol (DTT), weigh 400 mg of commercial bovine serum globulin (BSA) powder, dissolve it in 2 ml of the above denaturant solution, dissolve at 25 degrees Celsius for 1 h, and obtain a 200 mg / ml bovine serum globulin solution with chain expansion.

[0077] Step 2: Select the coagulation bath solution as follows: 70% ethanol, 1% hydrogen peroxide, 30% water, and adjust the pH to 1.0 using 12 mol / L hydrochloric acid;

[0078] Step 3: Select a metal long needle with an inner diameter of 0.200 mm, an outer diameter of 0.600 mm, and a length of 100 mm. Use a syringe pump to squeeze the pure globulin solution into the coagulation bath solution through the long needle at a speed of 10 μL / min. The protein solution is converted into fibers in the coagulation bath and collected by a rotary drum at a collection rate of 5 m / min. At this time, the stretch ratio λ is 1.0. Let the collected fibers dry at room temperature for 2 hours.

[0079] Through the above steps, continuous pure globulin fibers can be prepared, resulting in fibers with a uniform and smooth surface, such as... Figure 9 As shown, the tensile test reveals that, as Figure 10 As shown, the tensile strength of the obtained keratin / BSA composite fiber is approximately 49.8 ± 3.9 MPa, the elongation is 111.2 ± 23.8%, and the corresponding toughness is 24.8 ± 5.4 MJ / m. 3 The strength and toughness of the pure globulin fiber are significantly lower than those of the composite fiber in Example 2. This is because the pure globulin fiber lacks a rigid structure that can enhance strength and is mostly a random coil structure. Therefore, it exhibits lower breaking strength and higher tensile strain.

[0080] Example 3

[0081] Following the process of Example 2, the volume ratio of keratin to globulin is 3:2, and the stretch ratio of fiber collection is changed to 3.0.

[0082] Following the above steps, keratin / BSA composite fibers with a high draw ratio can be prepared. Scanning electron microscopy characterization shows that the composite fibers under these high draw ratio conditions have a smoother surface and more uniform dimensions, with the fiber diameter reduced to ~14 micrometers. Figure 11 As shown;

[0083] Tensile testing can reveal that, Figure 12 As shown, the obtained keratin composite fiber has a tensile strength of 249.9±8.3 MPa, a high elongation of 40.8±4.5%, and a corresponding toughness of approximately 69.8±10.0 MJ / m. 3 The strength of this composite fiber is significantly improved compared to the composite fiber in Example 1, while the fiber's extensibility and toughness are reduced. This is mainly because, under high draw ratio conditions, the defective structures inside the fiber are eliminated, and the stretching process consumes the potential strain inside the original fiber, thus leading to a decrease in strain and toughness. Simultaneously, more β-sheet structures are formed inside the fiber during stretching, enhancing the interactions between protein molecules. Therefore, a high-strength and high-toughness composite fiber is obtained.

[0084] As shown in Table 1, by comparing with Comparative Examples 2 and 3 and Examples 1, 2, and 3, a protein composite fiber with the best overall mechanical properties was obtained when the keratin to albumin ratio was adjusted to 3:2 and the stretch ratio was set to 3.0. Furthermore, cyclic tensile testing of this fiber revealed that, regardless of whether the strain was set at 5% or 20%, the fiber exhibited superior performance. Figure 13 As shown, the tensile strength did not decrease significantly, indicating that the fiber has good mechanical stability.

[0085] Table 1 Comparison of mechanical properties of protein fibers under different embodiment conditions

[0086]

[0087] Example 4

[0088] Following the process of Example 2, the volume ratio of keratin to globulin is 3:2, and the stretch ratio of fiber collection is changed to 3.0.

[0089] Furthermore, DTT aqueous solutions of 0.01, 0.02, and 0.03 mol / L were prepared, and the composite fibers obtained above were placed in DTT solutions of different concentrations and reacted for 12 hours respectively. After that, the fibers were taken out, dried, and their mechanical properties were tested.

[0090] Furthermore, a 2% hydrogen peroxide aqueous solution was prepared, and the fibers that had been reduced by DTT were placed in the hydrogen peroxide aqueous solution and reacted for 12 hours. After that, the fibers were taken out, dried, and their mechanical properties were tested.

[0091] After the above steps, it was found that the mechanical properties of the prepared high-strength and high-toughness keratin composite fibers decreased to varying degrees after treatment with reducing agents. With increasing DTT concentration, the mechanical strength gradually decreased. This is because DTT can break the disulfide bonds within the fiber, reducing the degree of cross-linking and thus leading to a decrease in fiber strength and toughness. Upon further treatment with a 2% hydrogen peroxide solution, the broken disulfide bonds regenerated, and the mechanical properties of the fibers returned to their original levels. This indicates that the prepared high-strength and high-toughness keratin composite fibers possess excellent dynamic mechanical properties. Figure 14 As shown in Table 2.

[0092] Table 2 Comparison of reversible mechanical properties of keratin / globulin composite fibers under different treatment conditions

[0093]

[0094] Example 5

[0095] The keratin / globulin composite fiber obtained in Example 4 was soaked in PBS for 4 hours, cleaned, and then sterilized by UV light for 30 minutes.

[0096] Furthermore, the fibers were placed in a 48-well plate, and mouse fibroblasts (L929) were added for in vitro cell culture. After 24 hours, cell growth was observed using a fluorescence microscope.

[0097] The results are as follows Figure 15 As shown, L929 cells exhibited good biological activity after 24 hours, were able to grow normally and attach to protein fibers, indicating that the prepared keratin / globulin composite fibers have excellent cell compatibility.

Claims

1. A method for preparing regenerated protein composite fibers, characterized in that, Including the following steps: Step 1: Regenerated keratin and regenerated globulin are treated with a denaturing solution to obtain denatured proteins; the denaturing solution includes a solvent, a reducing agent, and water. Step 2: Mix denatured keratin solution and denatured globulin solution and age to obtain protein complex solution; the mass ratio of denatured keratin to denatured globulin in Step 2 is 4:1-1:4; Step 3: Wet spinning of the protein composite solution to obtain the regenerated protein composite fiber.

2. The method for preparing regenerated protein composite fibers according to claim 1, characterized in that, The regenerated keratin includes at least one of wool keratin, feather keratin, hair keratin, and hoof keratin; Regenerated globulins include at least one of bovine serum albumin, horse serum albumin, rabbit serum albumin, ovalbumin, porcine serum albumin, rat serum albumin, β-lactoglobulin, regenerated soybean protein, and regenerated sericin.

3. The method for preparing regenerated protein composite fibers according to claim 1, characterized in that, The molar concentration of the solvent in the denatured solution is 6-10 mol / L; the molar concentration of the reducing agent is 0.01-0.5 mol / L.

4. The method for preparing regenerated protein composite fiber according to claim 3, characterized in that, The solvent includes urea and / or guanidine hydrochloride; The reducing agent includes one or more of dithiothreitol, β-mercaptoethanol, cysteine, reduced glutathione, mercaptoacetic acid, sodium mercaptoacetate, sodium sulfide, sodium sulfite, and tris(2-carbonylethyl)phosphohydrochloride.

5. The method for preparing regenerated protein composite fiber according to claim 1, characterized in that, In step 2, the mass concentration of the denatured keratin solution or denatured globulin solution is 100-300 mg / L; The aging time in step 2 is 5 minutes to 4 hours.

6. The method for preparing regenerated protein composite fibers according to claim 1, characterized in that, The coagulation bath for wet spinning consists of 60-80% v / v ethanol or methanol, 1-2% v / v hydrogen peroxide and water, and the pH of the coagulation bath is 1-3.

7. The method for preparing regenerated protein composite fiber according to claim 1, characterized in that, The coagulation bath for wet spinning consists of 50-70% v / v ethanol or methanol, 1-2% v / v hydrogen peroxide, 10-30% v / v acetic acid and water, and the pH of the coagulation bath is 1-3.

8. The method for preparing regenerated protein composite fiber according to claim 1, characterized in that, In step 3, the extrusion speed of wet spinning is 5-50 μL / min; the draw ratio is 1.0-5.

0.

9. The regenerated protein composite fiber prepared by the preparation method according to any one of claims 1-8.

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