Method for preparing high-strength regenerated cellulose filaments

Abstract

The invention discloses a method for preparing high-strength regenerated cellulose filaments, and belongs to the technical field of textiles. The preparation method of the high-strength regenerated cellulose filament comprises the following steps: firstly, pretreating bacterial cellulose to obtain a bacterial cellulose filter cake; dissolving the bacterial cellulose filter cake in NMMO (N-methylmorpholine-N-oxide) to obtain a transparent bacterial cellulose solution; adding a cross-linking solution prepared from tannic acid and / or polyethylene glycol diglycidyl ether into the bacterial cellulose solution for cross-linking reaction to obtain a spinning solution; and finally, carrying out wet spinning on the spinning solution to obtain the high-strength regenerated cellulose filament. The high-strength regenerated cellulose filament has high mechanical performance and stability, and can be widely applied to artificial tissue repair materials and drug sustained-release carriers in the field of biomedicine, antibacterial packaging materials in the field of food packaging and the like.

Description

Technical Field

[0001] The invention relates to a method for preparing high-strength regenerated cellulose filaments, belonging to the technical field of textiles. Background Art

[0002] Bacterial cellulose is an extracellular polysaccharide secreted by bacteria such as Acetobacter xylinum. It is an important natural cellulose material with broad application prospects. Bacterial cellulose has excellent properties that plant cellulose cannot match, such as high purity, high crystallinity, excellent shape retention and tear resistance, and has therefore attracted widespread attention. In addition, some properties of bacterial cellulose can be controlled during its synthesis, so it is considered to be the preferred cellulose. However, bacterial cellulose has a large molecular weight and poor spinnability, which seriously limits its development in high-end application fields. Summary of the invention

[0003] [Technical issues]

[0004] Bacterial cellulose has excellent mechanical properties, but its high molecular weight and poor spinnability make it difficult to prepare high-strength bacterial cellulose filaments, which seriously limits its widespread application.

[0005] [Technical solution]

[0006] In order to solve the above problems, the present invention first pre-treats bacterial cellulose to prepare a bacterial cellulose filter cake; then dissolves the bacterial cellulose filter cake in NMMO to obtain a transparent bacterial cellulose solution; then adds a cross-linking solution prepared by tannic acid and / or polyethylene glycol diglycidyl ether to the bacterial cellulose solution for cross-linking reaction to obtain a spinning solution; finally, the spinning solution is wet-spun to obtain high-strength regenerated cellulose filaments.

[0007] The first object of the present invention is to provide a method for preparing high-strength regenerated cellulose filaments, comprising the following steps:

[0008] (1) Preparation of bacterial cellulose filter cake

[0009] The bacterial cellulose is pre-treated, shredded, homogenized, filtered, and the water content is adjusted to 15-20% to obtain a bacterial cellulose filter cake;

[0010] (2) Preparation of bacterial cellulose solution

[0011] dissolving the bacterial cellulose filter cake in NMMO to obtain a bacterial cellulose solution with a concentration of 3-20%;

[0012] (3) Preparation of cross-linking solution

[0013] Dissolving the cross-linking agent in ethanol to obtain a cross-linking solution; the concentration of the cross-linking agent in ethanol is 1-5 mg / mL;

[0014] (4) Preparation of spinning solution

[0015] The cross-linking solution of step (3) is added dropwise to the bacterial cellulose solution of step (2) to react and obtain a spinning solution;

[0016] (5) Preparation of high-strength regenerated cellulose filaments

[0017] The spinning solution is wet-spun to obtain high-strength regenerated cellulose filaments.

[0018] In one embodiment of the present invention, the pretreatment in step (1) is to treat with a sodium hydroxide solution with a mass fraction of 1 to 3% for 30 to 60 minutes.

[0019] In one embodiment of the present invention, the shredding in step (1) is shredded into pieces of 2 to 5 mm.

[0020] In one embodiment of the present invention, the homogenization in step (1) is carried out using a high-speed homogenizer with a rotation speed of 10,000 to 20,000 rpm for 2 to 10 minutes.

[0021] In one embodiment of the present invention, the filtration in step (1) is performed under vacuum conditions.

[0022] In one embodiment of the present invention, the adjustment of the water content in step (1) is achieved by extrusion.

[0023] In one embodiment of the present invention, the bacterial cellulose filter cake in step (2) is dissolved in NMMO at 80-100° C., 100-500 rpm / min, and vacuum for 30-60 min.

[0024] In one embodiment of the present invention, the mass ratio of tannic acid to polyethylene glycol diglycidyl ether in the cross-linking agent in step (3) is 1-2:1.

[0025] In one embodiment of the present invention, the ethanol in step (3) is anhydrous ethanol.

[0026] In one embodiment of the present invention, the concentration in step (3) is 10-20 mmol / L.

[0027] In one embodiment of the present invention, the reaction conditions in step (3) are: temperature 80-90° C., and reaction time is 30-60 min at room temperature.

[0028] In one embodiment of the present invention, the dripping speed in step (4) is 10-30 mL / min.

[0029] In one embodiment of the present invention, the reaction in step (4) is carried out at pH 5-7 and 50-70° C. for 8-12 hours.

[0030] In one embodiment of the present invention, the parameters of wet spinning in step (5) are set as follows: the spinning solution is injected into the anhydrous ethanol medium at a speed of 0.1 to 0.5 ml / s, and after the injection, the bacterial cellulose filaments are immersed in anhydrous ethanol for a coagulation time of 100 to 120 s.

[0031] The second object of the present invention is to provide a high-strength regenerated cellulose filament prepared by the above-mentioned method.

[0032] The third object of the present invention is to provide application of the high-strength regenerated cellulose filaments described above in the field of functional textiles.

[0033] In one embodiment of the present invention, the application is artificial tissue repair materials, drug sustained-release carriers, etc. in the biomedical field, and antibacterial packaging materials in the food packaging field.

[0034] [Beneficial Effects]

[0035] (1) The high-strength regenerated cellulose filaments prepared by the present invention have high strength: a cross-linked network structure is formed by the reaction of the cross-linking agent and the bacterial cellulose, thereby effectively improving the strength of the bacterial cellulose;

[0036] (2) The high-strength regenerated cellulose filaments prepared by the present invention have good stability: the introduction of the cross-linking agent makes the bacterial cellulose membrane material have better stability, can maintain good performance for a long time under different environmental conditions, and reduces the phenomenon of fabric fibrillation during subsequent use;

[0037] (3) The high-strength regenerated cellulose filaments prepared by the present invention have good biocompatibility: bacterial cellulose itself has excellent biocompatibility and biodegradability;

[0038] (4) The high-strength regenerated cellulose filaments prepared by the present invention have a wide range of applications: they can be widely used in artificial tissue repair materials, drug sustained-release carriers, etc. in the biomedical field, and antibacterial packaging materials in the food packaging field, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the cross-linking of bacterial cellulose and tannic acid in Example 2;

[0040] Figure 2 The mechanical properties test diagram of the high-strength regenerated cellulose filaments prepared in Comparative Example 1 and Examples 2-6;

[0041] Figure 3It is a test diagram of the mechanical properties of high-strength regenerated cellulose filaments prepared in Comparative Example 1, Examples 1-2, and Examples 7-9. DETAILED DESCRIPTION

[0042] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explaining the present invention and are not used to limit the present invention.

[0043] The test method used in the present invention

[0044] 1. Mechanical properties test

[0045] Test the tensile strength of the filament: divided into three steps: filament separation, fixed sheet reinforcement, and testing. First, use tweezers to separate the single filament of appropriate length, and reinforce the selected single filament on a piece of paper to avoid single filament breakage. During the test, one end of the test sample is clamped on the upper clamp of the electronic fiber strength tester, and the other end of the sample is clamped on the lower clamp. The sample is stretched at a constant tensile speed until the sample breaks. Use a filament clamp with a length of 20mm and a crosshead speed of 20mm / min. Record the technical indicators such as the breaking strength and breaking elongation of the single value. After the test, the instrument automatically gives the statistical values ​​of all technical indicators.

[0046] 2. Stability performance test

[0047] Test the thermal stability of the filaments: After the obtained filaments were placed at 80°C for 60 minutes, their mechanical properties were measured again, which showed little difference from those at room temperature, proving that the thermal performance of the filaments spun after cross-linking the bacterial cellulose with the cross-linking agent was greatly improved.

[0048] The raw materials used in the examples are:

[0049] Bacterial cellulose: The diameter of bacterial fibers is 50-100nm, the length is greater than 20um, and the water absorption rate is about 200 times.

[0050] N-Methylmorpholine-N-oxide (NMMO): Use high-grade pure (GR) NMMO reagent, that is, the NMMO content is above 99.8%.

[0051] Polyethylene glycol diglycidyl ether: molecular weight is about 6000, pH value is between 4.0 and 7.0, (5%, Water).

[0052] Tannic acid: purchased from Tongshan County Hongda Fine Chemical Factory, molecular weight 153.33, tannic acid content greater than 99.5%.

[0053] Example 1

[0054] A method for preparing high-strength regenerated cellulose filaments comprises the following steps:

[0055] (1) Preparation of bacterial cellulose filter cake

[0056] The bacterial cellulose was treated in a sodium hydroxide aqueous solution with a mass fraction of 1% for 30 minutes, and then shredded into 2 mm pieces, treated with a high-speed homogenizer at 15000 rpm for 30 minutes, vacuum filtered, and the filter cake was taken. The filter cake was extruded at room temperature using a hot press, and the water content was adjusted to 15% to obtain a bacterial cellulose filter cake;

[0057] (2) Preparation of bacterial cellulose solution

[0058] The bacterial cellulose filter cake was dissolved in NMMO, the environment was evacuated to vacuum using a vacuum pump, and the mixture was stirred at 100°C and 360 rpm / min for 40 min to obtain a bacterial cellulose solution with a mass concentration of 8%;

[0059] (3) Preparation of cross-linking solution

[0060] Dissolving polyethylene glycol diglycidyl ether powder in anhydrous ethanol, reacting at 90° C. for 60 minutes to obtain a cross-linking solution; wherein the concentration of polyethylene glycol diglycidyl ether in anhydrous ethanol is 5 mg / mL;

[0061] (4) Preparation of spinning solution

[0062] The cross-linking solution prepared in step (3) was added dropwise to the bacterial cellulose solution in step (2) at a dropping speed of 15 mL / min, the pH value of the solution was adjusted to 6, and the reaction was carried out at 60° C. for 10 h to obtain a spinning solution;

[0063] (5) Preparation of filaments

[0064] The spinning solution prepared in step (4) is wet-spun, the spinning solution is injected into anhydrous ethanol medium at a speed of 0.5 ml / s, and the fiber filaments formed by spinning are immersed in anhydrous ethanol and coagulated for 120 seconds to obtain high-strength regenerated cellulose filaments.

[0065] Example 2

[0066] A method for preparing high-strength regenerated cellulose filaments comprises the following steps:

[0067] (1) Preparation of bacterial cellulose filter cake

[0068] The bacterial cellulose was treated in a sodium hydroxide aqueous solution with a mass fraction of 1% for 30 minutes, and then shredded into 2 mm pieces, treated with a high-speed homogenizer at 15000 rpm for 30 minutes, vacuum filtered, and the filter cake was taken. The filter cake was extruded at room temperature using a hot press, and the water content was adjusted to 15% to obtain a bacterial cellulose filter cake;

[0069] (2) Preparation of bacterial cellulose solution

[0070] The bacterial cellulose filter cake was dissolved in NMMO, the environment was evacuated to vacuum using a vacuum pump, and the mixture was stirred at 100°C and 360 rpm / min for 40 min to obtain a bacterial cellulose solution with a mass concentration of 8%;

[0071] (3) Preparation of cross-linking solution

[0072] Dissolving tannic acid powder in anhydrous ethanol and reacting at 90° C. for 60 minutes to obtain a cross-linking solution; wherein the concentration of tannic acid in anhydrous ethanol is 5 mg / mL;

[0073] (4) Preparation of spinning solution

[0074] The cross-linking solution prepared in step (3) was added dropwise to the bacterial cellulose solution in step (2) at a dropping speed of 15 mL / min, the pH value of the solution was adjusted to 6, and the reaction was carried out at 60° C. for 10 h to obtain a spinning solution;

[0075] (5) Preparation of filaments

[0076] The spinning solution prepared in step (4) is wet-spun, the spinning solution is injected into anhydrous ethanol medium at a speed of 0.5 ml / s, and the fiber filaments formed by spinning are immersed in anhydrous ethanol and coagulated for 120 seconds to obtain high-strength regenerated cellulose filaments.

[0077] Example 3

[0078] The concentration of tannic acid in step (3) of Example 2 was adjusted to 1 mg / mL, and the other conditions were kept consistent with Example 2 to obtain high-strength regenerated cellulose filaments.

[0079] Example 4

[0080] The concentration of tannic acid in step (3) of Example 2 was adjusted to 2 mg / mL, and the other conditions were kept consistent with Example 2 to obtain high-strength regenerated cellulose filaments.

[0081] Example 5

[0082] The concentration of tannic acid in step (3) of Example 2 was adjusted to 3 mg / mL, and the other conditions were kept consistent with Example 2 to obtain high-strength regenerated cellulose filaments.

[0083] Example 6

[0084] The concentration of tannic acid in step (3) of Example 2 was adjusted to 4 mg / mL, and the other conditions were kept consistent with Example 2 to obtain high-strength regenerated cellulose filaments.

[0085] Example 7

[0086] The tannic acid powder in step (3) of Example 2 is adjusted to a mixture of tannic acid and polyethylene glycol diglycidyl ether in a mass ratio of 1:1, and the other parts are consistent with Example 2 to obtain high-strength regenerated cellulose filaments.

[0087] Example 8

[0088] The tannic acid powder in step (3) of Example 2 is adjusted to a mixture of tannic acid and polyethylene glycol diglycidyl ether, and the mass ratio of the two is 1.5:1. The other conditions are consistent with Example 2 to obtain high-strength regenerated cellulose filaments.

[0089] Example 9

[0090] The tannic acid powder in step (3) of Example 2 is adjusted to a mixture of tannic acid and polyethylene glycol diglycidyl ether in a mass ratio of 2:1, and the other parts are consistent with Example 2 to obtain high-strength regenerated cellulose filaments.

[0091] Comparative Example 1

[0092] Steps (3) and (4) of Example 1 are omitted, and the bacterial cellulose solution obtained in step (2) is directly spun to obtain high-strength regenerated cellulose filaments.

[0093] Comparative Example 2

[0094] The concentration of tannic acid in step (3) of Example 2 was adjusted to 10 mg / mL, and the other conditions were kept consistent with Example 2 to obtain high-strength regenerated cellulose filaments.

[0095] Comparative Example 3

[0096] The tannic acid powder in step (3) of Example 2 was adjusted to trimethylolpropane, and the other parts were kept consistent with Example 2 to obtain high-strength regenerated cellulose filaments.

[0097] Comparative Example 4

[0098] The tannic acid powder in step (3) of Example 2 is adjusted to a mixture of 1,2,3,4-butanetetracarboxylic acid and polyethylene glycol diglycidyl ether in a mass ratio of 1:1, and the other parts are consistent with Example 2 to obtain high-strength regenerated cellulose filaments.

[0099] Comparative Example 5

[0100] Step (1) of Example 2 was omitted, bacterial cellulose was directly used, and the rest of the steps were the same as in Example 2 to obtain high-strength regenerated cellulose filaments.

[0101] Results Analysis

[0102] The high-strength regenerated cellulose filaments obtained in Examples 1-9 and Comparative Examples 1-5 were subjected to performance tests, and the test results are as follows:

[0103] Table 1. Mechanical properties of high-strength regenerated cellulose filaments

[0104] Tensile strength(Mpa) Young's modulus (Gpa) Example 1 195 5 Example 2 395 11 Example 3 168 4 Example 4 217 6 Example 5 258 7 Example 6 315 8 Example 7 414 15 Example 8 486 18 Example 9 523 22 Comparative Example 1 146 2 Comparative Example 2 200 8 Comparative Example 3 300 10 Comparative Example 4 320 10 Comparative Example 5 98 5

[0105] Combined with Table 1 Figure 2 It can be seen that compared with Comparative Example 1, after adding tannic acid as a cross-linking agent to carry out cross-linking reaction with bacterial cellulose in Examples 2 to 6, the mechanical properties of the obtained high-strength regenerated cellulose filaments are significantly increased, and with the increase of the cross-linking agent concentration, the tensile strength of the high-strength regenerated cellulose filaments is also enhanced. When the tannic acid concentration is 5 mg / ml, the tensile strength can reach 395 MPa and the Young's modulus is 11 Gpa.

[0106] Combination Figure 3 It can be seen that, compared with Examples 1-2 and Comparative Example 1, Examples 7-9 use a mixed component of tannic acid and polyethylene glycol diglycidyl ether as a crosslinking agent to treat bacterial cellulose better than a single component crosslinking agent. When the ratio of polyvinyl alcohol to tannic acid is 2:1, the mechanical properties of high-strength regenerated cellulose filaments are optimal, with a tensile strength of 523Mpa and a Young's modulus of 22Gpa.

[0107] Among them, the breaking strength and tensile properties of the high-strength regenerated cellulose filaments of Comparative Example 2 were significantly reduced, with a breaking strength of 200 MPa and a Young's modulus of 8 Gpa, indicating that too high a crosslinking agent concentration would lead to a decrease in the mechanical properties of the filaments.

[0108] The mechanical properties of the high-strength regenerated cellulose filaments in Comparative Example 3 can still be improved to a certain extent, but the effect is not as significant as that of tannic acid as a cross-linking agent. Its tensile strength is lower than that of Example 2, which is 300 MPa, and its Young's modulus is 10 Gpa.

[0109] The mechanical properties of the high-strength regenerated cellulose filaments of Comparative Example 4 are improved compared with those of Example 2, but compared with Example 7, the improvement effect on the mechanical properties of the high-strength regenerated cellulose filaments is not outstanding, and its tensile strength is 320 MPa and Young's modulus is 10 Gpa.

[0110] In comparative example 5, without pretreatment of bacterial cellulose, the properties of the filaments obtained were significantly reduced, with a tensile strength of 98 MPa and a Young's modulus of 5 GPa. Since the bacterial cellulose was not fully dissolved, the cross-linking reaction between the bacterial cellulose and the cross-linking agent was not fully carried out, resulting in a reduction in the mechanical properties of the filaments.

[0111] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A method for preparing high-strength regenerated cellulose filaments, characterized in that: The method comprises the following steps: (1) Preparation of bacterial cellulose filter cake The bacterial cellulose is pre-treated by cutting, homogenizing, filtering, and adjusting the water content to 15-20% to obtain a bacterial cellulose filter cake; (2) Preparation of bacterial cellulose solution dissolving the bacterial cellulose filter cake in NMMO to obtain a bacterial cellulose solution with a concentration of 3-20%; (3) Preparation of cross-linking solution Dissolving a crosslinking agent in ethanol to obtain a crosslinking solution; wherein the crosslinking agent is tannic acid or a mixture of tannic acid and polyethylene glycol diglycidyl ether; and the concentration of the crosslinking agent in ethanol is 1-5 mg / mL; (4) Preparation of spinning solution The cross-linking solution of step (3) is added dropwise to the bacterial cellulose solution of step (2) to react and obtain a spinning solution; (5) Preparation of high-strength regenerated cellulose filaments The spinning solution is wet-spun to obtain high-strength regenerated cellulose filaments.

2. The method according to claim 1, characterized in that The pretreatment in step (1) is to treat with a sodium hydroxide solution with a mass fraction of 1 to 3% for 30 to 60 minutes.

3. The method according to claim 1, characterized in that In step (1), the homogenization is carried out by a high-speed homogenizer at a rotation speed of 10,000 to 20,000 rpm for 2 to 10 minutes.

4. The method according to claim 1, characterized in that: In step (2), the bacterial cellulose filter cake is dissolved in NMMO at 80-100° C., 100-500 rpm / min, and vacuum for 30-60 min.

5. The method according to claim 1, characterized in that In step (3), the mass ratio of tannic acid to polyethylene glycol diglycidyl ether in the cross-linking agent is 1-2:

1.

6. The method according to claim 1, characterized in that The reaction in step (4) is carried out at pH 5-7 and 50-70° C. for 8-12 hours.

7. The method according to claim 1, characterized in that The parameters of wet spinning in step (5) are set as follows: the spinning solution is injected into the anhydrous ethanol medium at a speed of 0.1 to 0.5 ml / s, and after the injection, the bacterial cellulose filaments are immersed in anhydrous ethanol for a coagulation time of 100 to 120 s.

8. High-strength regenerated cellulose filaments prepared by the preparation method according to any one of claims 1 to 7.

9. Application of the high-strength regenerated cellulose filaments according to claim 8 in the field of functional textiles.

10. The use according to claim 9, characterized in that: The application is artificial tissue repair materials in the biomedical field, drug sustained-release carriers, and antibacterial packaging materials in the food packaging field.

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