Method for preparing oxidized-sugar-crosslinked cellulose fibers

Abstract

The present invention relates to a method for preparing oxidized-sugar-crosslinked cellulose fibers. The method comprises the following steps: A, the preparation of an oxidized-sugar crosslinking agent, involving: dissolving 10-20 parts by weight of sugar and 20-40 parts by weight of a periodate in 300-500 parts by weight of deionized water, adding 10-20 parts by weight of barium chloride thereto, stirring same at 5-10°C for 1-2 h, filtering the mixed solution, and retaining a filtrate to obtain the oxidized-sugar crosslinking agent for later use; B, the preparation of cellulose fibers, involving: weighing 50-100 parts by weight of cellulose, adding same to a container containing 200-300 parts by weight of an ionic liquid, heating and stirring same at 85-105°C for 2-8 h to prepare a dissolved solution of cellulose fibers, and preparing the cellulose fibers on the basis of a wet spinning forming process; and C, the crosslinking treatment of the cellulose fibers, involving: immersing the cellulose fibers in an oxidized-sugar solution, crosslinking same at 30-60°C for 10-120 min, and then drying same at 105-125°C to obtain oxidized-sugar-crosslinked cellulose fibers. The process of the present invention is simple, is safe to implement, and can reduce enterprise costs.

Description

A method for preparing oxidized sugar cross-linked cellulose fibers Technical Field

[0001] The invention relates to a method for preparing oxidized sugar cross-linked cellulose fibers. Background Art

[0002] Cellulose, a cheap, renewable, and biodegradable resource, is the most abundant organic raw material in nature. Chemical modification can impart specific properties, transforming it into functional materials suitable for a variety of applications, such as cellulose fibers. However, directly prepared cellulose fibers suffer from low strength, limiting their application. Research on the modification of cellulose fibers is a hot topic among researchers both domestically and internationally.

[0003] In a Chinese invention patent with authorization announcement number CN112342634B, a method for preparing antibacterial nanocellulose fibers is disclosed. The method comprises the following steps: (1) preparing menthol-compounded zinc oxide microcapsules: mixing a menthol liquid paraffin solution with an acidic chitosan solution in operation A, adjusting the pH to 5.5-6.5 to obtain a mixed solution I, mixing the mixed solution I with nano-zinc oxide in operation B to obtain a mixed solution II, adding glutaraldehyde to the mixed solution II for cross-linking, and filtering to obtain the obtained solution; (2) spinning the mixed solution: mixing the menthol-compounded zinc oxide microcapsules with a spinning viscose stock solution, performing acid bath spinning, and preparing the antibacterial nanocellulose fibers through post-spinning treatment.

[0004] A Chinese invention patent application, publication number CN115944777A, discloses a genipin-crosslinked gelatin / glass fiber biomimetic scaffold, its preparation method, and its application. The biomimetic scaffold comprises a composite scaffold with dispersed SiO-2-CaO-P-2O-5 fibers. The SiO-2-CaO-P-2O-5 fibers are evenly distributed and staggered throughout the gelatin. The genipin-crosslinked gelatin at the fiber joints secures the fibers.

[0005] The papers "Study on Cross-linking Modification of Regenerated Cellulose Fibers with Glutaraldehyde" and "Study on Surface Cross-linking Modification of Cellulose Membranes with Glutaraldehyde" describe the use of glutaraldehyde as a cross-linking agent to modify cellulose fibers. Under physiological conditions, due to their high reactivity and volatility, small aldehyde molecules can react with proteins and DNA in the body, making them generally toxic and carcinogenic. Furthermore, highly volatile small aldehyde molecules are harmful to operators and the environment.

[0006] Cross-linking modification can effectively improve the strength of cellulose fibers, and researchers have found that glutaraldehyde and genipin have good cross-linking effects. Glutaraldehyde is a bifunctional chemical cross-linking agent. Its advantage is that it can be cross-linked under solution and steam conditions, but there are potential toxicity issues related to residual unreacted cross-linker groups. Genipin is an excellent natural cross-linking agent for protein materials and has been shown to be much less toxic than glutaraldehyde and other commonly used synthetic cross-linking reagents. However, its high cost (Sigma 25mg genipin costs 1,562 yuan) is the main disadvantage of actual use. Although the cellulose fibers prepared by the current existing technology have excellent properties, the process is relatively complicated, and the cross-linking agents are highly toxic or costly.

[0007] Based on the above issues, the applicant conducted research on the above issues and resulted in this case. Technical issues

[0008] The object of the present invention is to provide a method for preparing oxidized sugar cross-linked cellulose fibers with simple process, safety and low cost. Technical Solutions

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A method for preparing oxidized sugar cross-linked cellulose fibers comprises the following steps:

[0011] A. Preparation of an oxidized sugar crosslinker: Dissolve 10-20 parts by weight of sugar and 20-40 parts by weight of periodate in 300-500 parts by weight of deionized water, stir at 20-25°C for 6-24 hours, then add 10-20 parts by weight of barium chloride, and stir at 5-10°C for 1-2 hours. Filter the mixture, and retain the filtrate to obtain the oxidized sugar crosslinker for later use.

[0012] B. Preparation of cellulose fibers: 50-100 parts by weight of cellulose was added to a container containing 200-300 parts by weight of an ionic liquid. The mixture was heated and stirred at 85-105°C for 2-8 hours to prepare a cellulose fiber solution. Cellulose fibers were then prepared using a wet spinning process.

[0013] C. Cross-linking treatment of cellulose fibers: immerse the cellulose fibers in an oxidized sugar solution at a mass ratio of cellulose fibers to oxidized sugar cross-linking agent of 30:70-10:90. Cross-link for 10-120 min at 30-60°C. After cross-linking, remove the fibers, drain, and dry at 105-125°C to obtain oxidized sugar cross-linked cellulose fibers.

[0014] As a preferred embodiment of the present invention, the sugar is one or more of glucose, galactose, fructose, sucrose, maltose, raffinose, maltotriose, and maltotetraose.

[0015] As a preferred embodiment of the present invention, the periodate is sodium periodate or potassium periodate.

[0016] As a preferred embodiment of the present invention, the cellulose is bagasse cellulose, cotton cellulose or poplar cellulose.

[0017] As a preferred embodiment of the present invention, the ionic liquid is 1,3-dimethylimidazolium hexafluorophosphate, 1,3-dimethylimidazolium tetrafluoroborate or 1,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide.

[0018] As a preferred embodiment of the present invention, in the process of preparing cellulose fibers by wet spinning, the coagulation bath is a mixture of ionic liquid and water, the mass concentration of the ionic liquid in the mixture is not more than 60%, and the coagulation bath temperature is 5-10°C. Beneficial effects

[0019] After adopting the technical solution of the present invention, oxidized sugar cross-linked cellulose fibers were prepared under environmentally friendly material processing conditions. Sugar is one of the most basic food additives in daily life. It is non-toxic, renewable and exists in large quantities in natural plants. After oxidation with periodate, highly active aldehyde groups can be introduced on sugar molecules without reactive groups, making them a new type of bio-based cross-linking agent. The present invention completely precipitates excess periodate by adding barium chloride, eliminating the need for large amounts of water for filtration and cleaning, thereby reducing wastewater generation. Through research, it was found that with the increase of temperature and the extension of time, the reaction intensified, the cellulose fibers showed browning, and the breaking strength was significantly improved. The process of the present invention is simple, the process is safe, and it can reduce enterprise costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Type your figure caption description paragraph here. Best Mode for Carrying Out the Invention

[0021] Type here the best mode description paragraph of the invention. Modes for Carrying Out the Invention

[0022] In order to better understand the technical solution of the present invention, it is described in more detail below with reference to embodiments.

[0023] Example 1

[0024] The preparation method of bagasse cellulose fiber is made according to the following parameters:

[0025] 50g of bagasse cellulose was weighed and added to a three-necked flask containing 200g of 1,3-dimethylimidazolium hexafluorophosphate ionic liquid. The flask was placed in an oil bath and heated and stirred at 85°C for 8 hours to prepare a bagasse cellulose fiber solution. After conventional filtration and vacuum degassing, bagasse cellulose fibers were produced according to a wet spinning process. Wet spinning involves the following steps: preparing a spinning solution; extruding the solution through a spinneret to form a thin stream; coagulating the thin stream into spun fibers; and winding or directly post-processing the spun fibers. The coagulation bath used for coagulation is a mixture of 1,3-dimethylimidazolium hexafluorophosphate ionic liquid and water, with a mass concentration of 20% ionic liquid. The coagulation bath temperature is 5°C. After stretching, washing, and drying, the bagasse cellulose fibers were obtained. The strength of the cellulose fibers was measured using an electronic universal testing machine. The cellulose fibers produced under these conditions achieved a breaking strength of 11 MPa.

[0026] Example 2

[0027] A method for preparing oxidized sugar cross-linked cellulose fibers is prepared according to the following parameters:

[0028] (1) Preparation of the oxidized glucose crosslinker: 5.42 g of sucrose and 19.50 g of sodium periodate were weighed and dissolved in 300 g of deionized water. The mixture was stirred at 25°C for 24 h. 11.20 g of barium chloride was then added and stirred at 5°C for 1 h to ensure that the periodate was fully precipitated. The mixture was then filtered and the filtrate was retained. The filtrate was clear and transparent and contained the oxidized glucose crosslinker. The filtrate was stored at 5°C for subsequent use.

[0029] (2) Weigh 50 g of bagasse cellulose and add it to a three-necked flask containing 200 g of 1,3-dimethylimidazolium hexafluorophosphate ionic liquid, place it in an oil bath, and heat and stir at 85°C for 8 hours to prepare a bagasse cellulose fiber solution. After conventional filtration and degassing under reduced pressure, bagasse cellulose fiber is prepared according to a wet spinning forming process. The coagulation bath is a mixture of 1,3-dimethylimidazolium hexafluorophosphate ionic liquid and water, wherein the mass concentration of the ionic liquid is 20%, and the coagulation bath temperature is 5°C. After stretching, washing, and drying, bagasse cellulose fiber is obtained.

[0030] (3) Cross-linking treatment of bagasse cellulose fibers: Bagasse cellulose fibers were immersed in an oxidized glucose solution with a mass ratio of 30:70. The fibers were cross-linked at 30°C for 10 min. After cross-linking, the fibers were removed, drained, and placed in a 105°C constant temperature oven to complete the surface chemical cross-linking reaction, thereby obtaining oxidized sucrose-cross-linked bagasse cellulose fibers. The strength of the cellulose fibers was measured using an electronic universal testing machine. The breaking strength of the bagasse cellulose fibers prepared under these conditions reached 16 MPa.

[0031] Example 3

[0032] A method for preparing oxidized sugar cross-linked cellulose fibers is prepared according to the following parameters:

[0033] (1) Preparation of oxidized sucrose crosslinker: 8.5 g of sucrose and 19.50 g of sodium periodate were dissolved in 300 g of deionized water and stirred at 25°C for 24 h. 11.20 g of barium chloride was then added and stirred at 5°C for 1 h to ensure that the periodate was fully precipitated. The mixture was then filtered and the filtrate was retained. The filtrate was clear and transparent and contained the oxidized sucrose crosslinker. The filtrate was stored at 5°C for subsequent use.

[0034] (2) Weigh 50 g of bagasse cellulose and add it to a three-necked flask containing 200 g of 1,3-dimethylimidazolium hexafluorophosphate ionic liquid. Place the flask in an oil bath and heat and stir at 85°C for 8 h to prepare a bagasse cellulose fiber solution. After filtration and vacuum degassing, bagasse cellulose fiber is prepared according to a wet spinning process. The coagulation bath is a mixture of 1,3-dimethylimidazolium hexafluorophosphate ionic liquid and water, wherein the mass concentration of the ionic liquid is 20%, and the coagulation bath temperature is 5°C. After stretching, washing, and drying, bagasse cellulose fiber is obtained.

[0035] (3) Cross-linking treatment of bagasse cellulose fibers: Bagasse cellulose fibers were immersed in an oxidized sucrose solution with a mass ratio of bagasse cellulose fibers to oxidized sucrose of 30:70. The fibers were cross-linked at 30°C for 10 min. After cross-linking, the fibers were removed, drained, and placed in a 105°C constant temperature oven to complete the surface chemical cross-linking reaction, thereby obtaining oxidized sucrose-cross-linked bagasse cellulose fibers. The strength of the cellulose fibers was measured using an electronic universal testing machine. The breaking strength of the bagasse cellulose fibers prepared under these conditions reached 18.5 MPa.

[0036] Example 4

[0037] A method for preparing oxidized sugar cross-linked cellulose fibers is prepared according to the following parameters:

[0038] (1) Preparation of oxidized sucrose crosslinker: 10.26 g of sucrose and 19.50 g of sodium periodate were weighed and dissolved in 300 g of deionized water. The mixture was stirred at 25°C for 24 h. 11.20 g of barium chloride was then added and stirred at 5°C for 1 h to ensure that the periodate was fully precipitated. The mixture was then filtered and the filtrate was retained. The filtrate was clear and transparent and contained the oxidized sucrose crosslinker. The filtrate was stored at 5°C for subsequent use.

[0039] (2) Weigh 50 g of bagasse cellulose and add it to a three-necked flask containing 200 g of 1,3-dimethylimidazolium hexafluorophosphate ionic liquid. Place the flask in an oil bath and heat and stir at 85°C for 8 h to prepare a bagasse cellulose fiber solution. After filtration and vacuum degassing, bagasse cellulose fiber is prepared according to a wet spinning process. The coagulation bath is a mixture of 1,3-dimethylimidazolium hexafluorophosphate ionic liquid and water, wherein the mass concentration of the ionic liquid is 20%, and the coagulation bath temperature is 5°C. After stretching, washing, and drying, bagasse cellulose fiber is obtained.

[0040] (3) Cross-linking treatment of bagasse cellulose fibers: Bagasse cellulose fibers were immersed in an oxidized sucrose solution with a mass ratio of 30:70. The fibers were cross-linked at 30°C for 10 min. After cross-linking, the fibers were removed, drained, and placed in a 105°C constant temperature oven to complete the surface chemical cross-linking reaction, thereby obtaining oxidized sucrose-cross-linked bagasse cellulose fibers. The strength of the cellulose fibers was measured using an electronic universal testing machine. The breaking strength of the bagasse cellulose fibers prepared under these conditions reached 22 MPa.

[0041] Example 5

[0042] A method for preparing oxidized sugar cross-linked cellulose fibers is prepared according to the following parameters:

[0043] (1) Preparation of oxidized sucrose crosslinker: 12.25 g of sucrose and 19.50 g of sodium periodate were weighed and dissolved in 300 g of deionized water. The mixture was stirred at 25°C for 24 h. 11.20 g of barium chloride was then added and stirred at 5°C for 1 h to ensure that the periodate was fully precipitated. The mixture was then filtered and the filtrate was retained. The filtrate was clear and transparent and contained the oxidized sucrose crosslinker. The filtrate was stored at 5°C for subsequent use.

[0044] (2) Weigh 50 g of bagasse cellulose and add it to a three-necked flask containing 200 g of 1,3-dimethylimidazolium hexafluorophosphate ionic liquid. Place the flask in an oil bath and heat and stir at 85°C for 8 h to prepare a bagasse cellulose fiber solution. After filtration and vacuum degassing, bagasse cellulose fiber is prepared according to a wet spinning process. The coagulation bath is a mixture of 1,3-dimethylimidazolium hexafluorophosphate ionic liquid and water, wherein the mass concentration of the ionic liquid is 20%, and the coagulation bath temperature is 5°C. After stretching, washing, and drying, bagasse cellulose fiber is obtained.

[0045] (3) Cross-linking treatment of bagasse cellulose fibers: Bagasse cellulose fibers were immersed in an oxidized sucrose solution with a mass ratio of 30:70. The fibers were cross-linked at 30°C for 10 min. After cross-linking, the fibers were removed, drained, and placed in a 105°C constant temperature oven to complete the surface chemical cross-linking reaction, thereby obtaining oxidized sucrose-cross-linked bagasse cellulose fibers. The strength of the cellulose fibers was measured using an electronic universal testing machine. The breaking strength of the bagasse cellulose fibers prepared under these conditions reached 19.1 MPa.

[0046] In the present invention, as the concentration of the oxidized sugar solution increases, the hydroxyl groups on the regenerated cellulose fiber molecular chains react fully with their aldehyde groups, strengthening the interaction between the molecular segments and increasing the degree of crosslinking, thereby improving the fiber's mechanical properties. However, when the amount of oxidized sugar crosslinker increases to a certain level, the density of crosslinking points becomes excessive, restricting intermolecular sliding and thus reducing the fiber's mechanical properties.

[0047] Example 6-8

[0048] Except for the change in cross-linking time, the other conditions were the same as those in Example 4. The properties of the obtained bagasse cellulose fibers are shown in the following table:

[0049]

[0050] Increasing the reaction temperature in the present invention increases the speed of regenerated cellulose molecules, promoting the reaction and gradually improving the mechanical properties of sucrose cellulose fibers. Properly increasing the temperature can increase the reaction rate and fluidity of the reactants, thereby increasing the speed of the cross-linking reaction. However, the speed of the cross-linking reaction has a certain limit. Once the temperature reaches a certain value, increasing the reaction temperature has no significant effect on the mechanical properties of the fiber.

[0051] Example 9

[0052] A method for preparing oxidized sugar cross-linked cellulose fibers is prepared according to the following parameters:

[0053] (1) Preparation of oxidized sucrose crosslinker: 10.26 g of sucrose and 19.50 g of sodium periodate were weighed and dissolved in 300 g of deionized water. The mixture was stirred at 25°C for 24 h. 11.20 g of barium chloride was then added and stirred at 5°C for 1 h to ensure that the periodate was fully precipitated. The mixture was then filtered and the filtrate was retained. The filtrate was clear and transparent and contained the oxidized sucrose crosslinker. The filtrate was stored at 5°C for subsequent use.

[0054] (2) Weigh 50 g of bagasse cellulose and add it to a three-necked flask containing 200 g of 1,3-dimethylimidazolium hexafluorophosphate ionic liquid. Place the flask in an oil bath and heat and stir at 85°C for 8 h to prepare a bagasse cellulose fiber solution. After filtration and vacuum degassing, bagasse cellulose fiber is prepared according to a wet spinning process. The coagulation bath is a mixture of 1,3-dimethylimidazolium hexafluorophosphate ionic liquid and water, wherein the concentration of the ionic liquid is 20%, and the coagulation bath temperature is 5°C. After stretching, washing, and drying, bagasse cellulose fiber is obtained.

[0055] (3) Strong cross-linking treatment of bagasse cellulose fibers: Bagasse cellulose fibers were immersed in an oxidized sucrose solution with a mass ratio of 30:70. The fibers were cross-linked at 60°C for 120 min. After cross-linking, the fibers were removed, drained, and placed in a 105°C constant temperature oven to complete the surface chemical cross-linking reaction. The resulting oxidized sucrose strongly cross-linked bagasse cellulose fibers were obtained. The strength of the cellulose fibers was measured using an electronic universal testing machine. The breaking strength of the bagasse cellulose fibers prepared under these conditions reached 35 MPa.

[0056] Example 10-13

[0057] Except for the cross-linking time, the other parameters are the same as those in Example 9. The properties of the obtained bagasse cellulose fibers are shown in the following table:

[0058]

[0059] As the crosslinking time increases, the hydroxyl groups on the cellulose molecular chains bond more with the aldehyde groups of the oxidized thiazolinone crosslinking agent, increasing the interaction between the molecules and improving the fiber's mechanical properties. As the reaction continues, the number of crosslinks between the molecules increases, forming a large network structure. The density of crosslink points between the fibers increases, causing stress concentration during stretching, making the fibers brittle and leading to a decrease in fiber mechanical properties.

[0060] The protection scope of the present invention is not limited to this embodiment. For example, the content of the substance of the present invention can be increased or decreased in proportion. Anyone who makes similar changes to it is deemed to be within the protection scope of the present invention. Industrial Applicability

[0061] The process of the present invention is simple and safe, and can reduce enterprise costs. Sequence Listing Free Content

[0062] Type your sequence listing free description paragraph here.

Claims

1. A method for preparing oxidized sugar cross-linked cellulose fibers, characterized in that, It includes the following steps: A. Preparation of oxidized sugar crosslinking agent: Dissolve 10 - 20 parts by weight of sugar and 20 - 40 parts by weight of periodate in 300 - 500 parts by weight of deionized water, stir at 20 - 25 °C for 6 - 24 h, then add 10 - 20 parts by weight of barium chloride, and stir at 5 - 10 °C for 1 - 2 h. Filter the mixture and retain the filtrate to obtain the oxidized sugar crosslinking agent for standby; B. Preparation of cellulose fiber: Weigh 50 - 100 parts by weight of cellulose and add it to a container containing 200 - 300 parts by weight of ionic liquid. Heat and stir at 85 - 105 °C for 2 - 8 h to prepare a cellulose fiber dissolution solution, and prepare cellulose fiber according to the wet spinning forming process; C. Crosslinking treatment of cellulose fiber: Immerse the cellulose fiber in the oxidized sugar solution, and the mass ratio of cellulose fiber to oxidized sugar crosslinking agent is 30:70 - 10:

90. Crosslink at 30 - 60 °C for 10 - 120 min. After crosslinking is completed, take it out and drain, and dry at 105 - 125 °C to obtain oxidized sugar crosslinked cellulose fiber.

2. The preparation method of an oxidized sugar cross-linked cellulose fiber according to claim 1, characterized in that, The sugar is one or more of glucose, galactose, fructose, sucrose, maltose, raffinose, maltotriose, and maltotetrose.

3. The preparation method of an oxidized sugar cross-linked cellulose fiber according to claim 2, wherein, The periodate is sodium periodate or potassium periodate.

4. The preparation method of an oxidized sugar cross-linked cellulose fiber according to claim 3, wherein The cellulose is bagasse cellulose, cotton cellulose or poplar cellulose.

5. The preparation method of an oxidized sugar cross-linked cellulose fiber according to claim 4, characterized in that, The ionic liquid is 1,3 - dimethylimidazolium hexafluorophosphate, 1,3 - dimethylimidazolium tetrafluoroborate or 1,3 - dimethylimidazolium bis(trifluoromethylsulfonyl)imide.

6. The preparation method of an oxidized sugar cross-linked cellulose fiber according to claim 5, characterized in that, During the process of preparing cellulose fiber by wet spinning forming process, the coagulation bath is a mixed solution of ionic liquid and water. In the mixed solution, the mass concentration of the ionic liquid is not more than 60%, and the coagulation bath temperature is 5 - 10 °C.

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