阅读说明：本技术 一种利用pH值在6~8的壳聚糖溶液制备的纤维材料及其制备方法 (Fiber material prepared from chitosan solution with pH value of 6-8 and preparation method thereof ) 是由 蔡杰 钟奕 张俐娜 于 2019-03-29 设计创作，主要内容包括：本发明公开了一种利用pH值在6～8的壳聚糖溶液制备纤维材料及其制备方法。制备方法如下：(1)配制分散液；(2)将壳聚糖加入分散液中,控温在冰点至35℃,向溶液中通入二氧化碳,同时搅拌使壳聚糖溶解,当壳聚糖完全溶解后停止通入二氧化碳,经过脱泡后得到透明的pH值在6～8的壳聚糖溶液；(3)将壳聚糖溶液喷丝到凝固浴中凝固、再生,经过牵伸、洗涤、增塑后烘干得到壳聚糖纤维。本发明的有益效果：本发明提供的溶解方法在pH值在6～8的环境中进行,能够有效地减弱壳聚糖分子链的降解,提高在纺丝过程的稳定性,没有酸碱性物质残留。此外,还可以通过化学改性或者掺杂其他有机、无机、高分子材料进一步提升壳聚糖纤维的功能性。(The invention discloses a fiber material prepared by using a chitosan solution with a pH value of 6-8 and a preparation method thereof. The preparation method comprises the following steps: (1) preparing a dispersion liquid; (2) adding chitosan into the dispersion liquid, controlling the temperature to be between the freezing point and 35 ℃, introducing carbon dioxide into the solution, simultaneously stirring to dissolve the chitosan, stopping introducing the carbon dioxide after the chitosan is completely dissolved, and defoaming to obtain a transparent chitosan solution with the pH value of 6-8; (3) and spinning the chitosan solution into a coagulating bath for coagulation and regeneration, and obtaining the chitosan fiber after drafting, washing, plasticizing and drying. The invention has the beneficial effects that: the dissolving method provided by the invention is carried out in an environment with a pH value of 6-8, can effectively weaken the degradation of chitosan molecular chains, improves the stability in the spinning process, and has no acid and alkali substance residues. In addition, the functionality of the chitosan fiber can be further improved by chemical modification or doping with other organic, inorganic and high molecular materials.)

1. A method for preparing a fiber material by using a chitosan solution with a pH value of 6-8 is characterized by comprising the following steps:

(1) preparing a dispersion liquid;

(2) adding chitosan into the dispersion liquid, controlling the temperature to be between the freezing point and 35 ℃, introducing carbon dioxide into the solution, stirring the solution to dissolve the chitosan, and defoaming the solution to obtain a transparent chitosan solution with the pH value of 6-8;

(3) and (3) directly spraying the chitosan aqueous solution obtained in the step (2) by adopting a wet spinning method, allowing the chitosan aqueous solution to enter a coagulating bath for regeneration, or spraying the chitosan aqueous solution by adopting a dry spraying wet spinning method, solidifying and regenerating the chitosan aqueous solution in the coagulating bath, stretching the obtained filaments, removing a chemical reagent by using deionized water, oiling, drying and winding to obtain the chitosan fiber.

2. The method of claim 1, wherein: the dispersion is one or a mixture of two of a urea aqueous solution and a thiourea aqueous solution; the concentration of the urea aqueous solution is 6-60 wt%; the concentration of the thiourea aqueous solution is 3-14 wt%.

3. The method of claim 2, wherein: the concentration of the urea aqueous solution is 18-60 wt%; the concentration of the thiourea aqueous solution is 7-14 wt%.

4. The method of claim 1, wherein: the mass ratio of the chitosan to the dispersion liquid in the step (2) is 1: 7-1: 1000.

5. The method of claim 1, wherein: the coagulation bath for spinning is a single coagulation bath or a multi-stage coagulation bath; the coagulating bath is selected from one or more of amide, dimethyl sulfoxide, ethyl acetate, acetone, alcohols and salt.

6. The method of claim 5, wherein: the alcohol is selected from methanol and ethanol, and the concentration of the alcohol is 10-100 wt%; the salt is selected from ammonium salt, sodium salt, potassium salt, magnesium salt, calcium salt and aluminum salt, and the concentration of the salt solution is 5-40 wt%.

7. The method for preparing chitosan fiber material as claimed in claim 1, wherein step (2) is performed by removing air bubbles from the chitosan solution by high speed centrifugation, or by removing air bubbles from the chitosan solution by conventional vacuum static degassing and continuous degassing methods to obtain the chitosan spinning solution.

8. A chitosan fibre material as claimed in any one of claims 1 to 7.

9. A preparation method of functional chitosan fiber is characterized in that: introducing functional organic or inorganic additives, low-dimensional nano materials, or natural macromolecules or synthetic macromolecules into the chitosan fiber prepared by the method of claim 8 for blend spinning; the additives are added via the spinning dope or coagulation bath.

10. The method of claim 9, wherein the functional organic or inorganic additive is selected from the group consisting of plasticizers, reinforcing agents, refractory additives, dyes, optical stabilizers, antibacterial bacteriostats, conductive materials, and surfactants.

11. The method of claim 10, wherein the low dimensional nanomaterials are selected from the group consisting of graphene and its derivatives, carbon nanotubes and their derivatives, metal or metal oxide nanoparticles, organic framework compounds, layered nanomaterials.

12. The method according to claim 9, wherein the natural polymer or the synthetic polymer is selected from polymer nanofibers, cellulose and its derivatives, animal proteins, plant proteins, collagen, alginate, conductive polymers, polyethylene glycol, and polyvinyl alcohol.

13. A functional chitosan fiber, which is produced by the method according to any one of claims 9 to 12.

Technical Field

The invention belongs to the field of natural polymer synthesis, and particularly relates to a fiber material prepared by using a chitosan solution with a pH value of 6-8 and a preparation method thereof.

Background

The chitosan is a deacetylated product of chitin, and when the deacetylation degree of the chitin is more than 55%, the chitin is converted into chitosan which can be dissolved in an acidic aqueous solution. The chitosan has good biocompatibility and biodegradability, can promote wound healing, and has hemostatic effect. The chitosan solution obtained by dissolving the chitosan can be used for preparing new materials such as chitosan fiber, chitosan film, chitosan hydrogel, chitosan aerogel, chitosan microspheres and the like, and has good application prospect in the fields of separation and adsorption, biomedical materials, flexible electronic devices, heat insulation materials and the like.

Chitosan has a large number of hydrogen bonds both intra-and intermolecular, and is therefore difficult to dissolve in water and common organic solvents. The traditional method is to use low-concentration acetic acid or hydrochloric acid aqueous solution to dissolve chitosan, but chitosan is easy to degrade molecular chains of chitosan in acidic aqueous solution. Recently, some alkaline aqueous solvents have been developed to dissolve chitosan. The current alkaline aqueous solvents used to dissolve chitosan include lithium hydroxide-sodium hydroxide-urea combination (patent 201110099176.3), lithium hydroxide-potassium hydroxide-urea combination (patent 201310405191.5), sodium hydroxide-urea combination (Zhang W, Xia W.Disolution and stability of lithium in a soluble hydroxide/urea solution [ J ]. Journal of Applied Polymer Science,2014,131(3): 1082. multidot. 1090.) and lithium hydroxide-urea combination (Li C, Han Q, Guan Y, et al. Michael reaction of chitosan with acrylic acid in an aqueous alkali solution [ J ]. Polymer Bulletin,2015,72(8): 2087. multidot. 5.). The specific dissolving method is that firstly the chitosan is added into the alkaline hydrosolvents for soaking, then the mixture is frozen and frozen, finally the mixture is unfrozen and stirred at room temperature, and the chitosan is completely dissolved after one or more times of freezing-unfreezing. The freezing-thawing process consumes a large amount of energy, which is very disadvantageous for industrial applications, and thus, the efficiency of preparing the chitosan alkaline aqueous solution is to be improved.

The pH value of the pure water changes along with the temperature change, and the range of the pH value is 6-8. Besides acid and alkaline water solvents, reports about the water solvent with the pH value of 6-8 for dissolving chitosan are blank. Compared with a strong alkaline aqueous solvent and an acidic aqueous solvent, the chitosan is more stable in the aqueous solvent with the pH value of 6-8, and the degradation of chitosan molecular chains is not easy to occur. The chitosan is dissolved under strong acid or strong alkaline conditions, and the solution of the chitosan can have the problem of further degradation of the chitosan in the process of treatment or further processing into fibers, thereby influencing the performance of the fibers.

Disclosure of Invention

In order to solve the technical problem, the invention provides a method for preparing chitosan fibers by spinning a chitosan solution prepared by dissolving chitosan under the environment of pH 6-8.

The method enables the chitosan to be dissolved in the environment with the pH value of 6-8, can effectively reduce the degradation of chitosan molecules, and enables the formed chitosan solution to be more stable. Because the pH value of the solution is 6-8, acidic or alkaline substances cannot be remained in the subsequent spinning process, the stability is better, the degradation and aging are slower in the using process, and the solution can still keep better performance after being used for a long time. The prepared chitosan fiber and the functional chitosan fiber thereof can be used as a substitute of the traditional fiber material on one hand, so that the chitosan fiber and the functional chitosan fiber thereof can be widely applied to the fields of textile industry and biomedical materials; on the other hand, the chitosan can be used as a fibrous chitosan material and has potential application in the fields of catalysis, adsorption, capacitors and the like. In addition, functional groups and materials are introduced in the preparation process of the chitosan fiber, so that the functionality of the chitosan fiber is increased, and the application range of the chitosan fiber is expanded.

The specific scheme provided by the invention is as follows:

in a first aspect, a fiber material prepared by using a chitosan solution with a pH value of 6-8 and a preparation method thereof are provided.

The preparation method comprises the following steps:

(1) preparing a dispersion liquid;

(2) adding chitosan into the dispersion liquid, controlling the temperature to be between the freezing point and 35 ℃, introducing carbon dioxide into the solution, stirring the solution to dissolve the chitosan, and defoaming the solution to obtain a transparent chitosan solution with the pH value of 6-8;

(3) and (3) spinning the chitosan solution obtained in the step (2) into an ethanol water solution for solidification and regeneration, stretching the obtained filaments, removing chemical reagents by using deionized water, oiling, drying and winding to obtain the chitosan fibers.

Specifically, the dispersion is one or a mixture of two of a urea aqueous solution and a thiourea aqueous solution.

Further, the concentration of the urea aqueous solution is 6 to 60 wt%, and preferably, the concentration of the urea aqueous solution is 18 to 60 wt%.

Further, the concentration of the thiourea aqueous solution is 3 to 14 wt%, preferably, the concentration of the thiourea aqueous solution is 7 to 14 wt%.

Specifically, the mass ratio of the chitosan to the dispersion liquid in the step (2) is 1: 7-1: 1000. .

Specifically, the coagulation bath for spinning is a single coagulation bath or a multi-stage coagulation bath. The coagulating bath is selected from one or more of amide, dimethyl sulfoxide, ethyl acetate, acetone, alcohols, salts and acid.

And further. The alcohol is selected from methanol and ethanol, and the concentration of the alcohol is 10-100 wt%; the salt is selected from ammonium salt, sodium salt, potassium salt, magnesium salt, calcium salt and aluminum salt, and the concentration of the salt solution is 5-40 wt%.

Specifically, in order to obtain a high-quality chitosan spinning solution, in the step (2) of the method, the bubbles in the chitosan solution can be removed by a high-speed centrifugation method, or the bubbles in the chitosan solution can be removed by a common method of decompression, static removal and continuous defoaming to obtain the chitosan spinning solution. According to the difference of the defoaming mode and the viscosity of the chitosan solution, the defoaming time of the chitosan solution is more than 0.1 h.

In a second aspect, a functional chitosan fiber material and a preparation method thereof are provided.

The preparation method comprises the following steps: functional organic or inorganic additives and low-dimensional nano materials are introduced in the preparation process of the chitosan fiber, or natural high polymers or synthetic high polymers are introduced for blending spinning, and the additives can be added through spinning stock solution or coagulation bath.

Specifically, the functional organic or inorganic additive is selected from a plasticizer, a reinforcing agent, a refractory material additive, a dye, an optical stabilizer, an antibacterial bacteriostatic agent, a conductive material and a surfactant.

Further, the low-dimensional nano material is selected from graphene, carbon nano tube, silicon dioxide, carbon quantum dot and layered nano material. The natural polymer and the synthetic polymer of the blended spinning are selected from cellulose and derivatives thereof, animal protein, vegetable protein, alginate, conductive polymer, polyvinyl alcohol or polyethylene glycol.

The invention has the beneficial effects that:

(1) the dissolving method provided by the invention is carried out in an environment with a pH value of 6-8, so that the degradation of chitosan molecules can be effectively reduced, and the stability of chitosan in the dissolving process is high;

(2) the chitosan dissolution process is efficient, energy-saving, green and environment-friendly, is beneficial to improving the production efficiency and reducing the production cost, and can be used for large-scale production;

(3) the pH value of the prepared chitosan solution is 6-8, the chitosan solution used as a raw material of fibers is high in stability, and no acid or alkaline substance is left in the spinning and fiber using processes, so that the chitosan solution is safer;

(4) the prepared chitosan fiber and the functional chitosan fiber thereof can be widely applied to textile materials and biomedical materials; the catalyst has potential application in the fields of catalysis, adsorption, capacitors and the like; the functional group or material is introduced into the chitosan fiber for improvement, so that the functionality of the chitosan fiber is increased, and the application range of the chitosan fiber is expanded.

Detailed Description

The invention will be further illustrated with reference to specific examples, to which the present invention is not at all restricted.

The chitosan used in the following examples is extracted from natural shrimp shell, crab shell, squid parietal bone, diatom, insects and other organisms containing alpha-chitin and beta-chitin, and the specific extraction steps are soaking with alkaline solution to remove protein, soaking with acid solution to remove inorganic salt, decolorizing with oxidant, washing with water and drying to obtain purified chitin. The chitosan is prepared by deacetylation reaction of chitin in sodium hydroxide or potassium hydroxide aqueous solution.