阅读说明：本技术 一种磁性壳聚糖纤维及其制备方法 (Magnetic chitosan fiber and preparation method thereof ) 是由 刘大刚 苏凡 于 2020-12-22 设计创作，主要内容包括：本发明涉及一种磁性壳聚糖纤维及其制备方法,包括以下步骤：(1)制备壳聚糖溶液,(2)制备壳聚糖纤维材料,(3)水热反应预处理,(4)制备磁性壳聚糖纤维。本发明制备的磁性壳聚糖纤维直径为2-3mm,长度无限制。本发明利用壳聚糖与四氧化三铁作为主要原料,利用无毒无污染的壳聚糖作为纤维材料骨架、利用自然界广泛存在的四氧化三铁作为改性剂,制备得到的磁性壳聚糖纤维,具备铁磁性,具有一定的机械性能；另一方面,通过湿法纺丝,水热反应即可制得,制备过程简单、易于控制、成本低。(The invention relates to a magnetic chitosan fiber and a preparation method thereof, comprising the following steps: (1) preparing a chitosan solution, (2) preparing a chitosan fiber material, (3) carrying out hydrothermal reaction pretreatment, and (4) preparing a magnetic chitosan fiber. The diameter of the magnetic chitosan fiber prepared by the invention is 2-3mm, and the length is not limited. The magnetic chitosan fiber prepared by using chitosan and ferroferric oxide as main raw materials, using non-toxic and pollution-free chitosan as a fiber material framework and using ferroferric oxide widely existing in the nature as a modifier has ferromagnetism and certain mechanical property; on the other hand, the fiber can be prepared by wet spinning and hydrothermal reaction, and the preparation process is simple, easy to control and low in cost.)

1. A preparation method of magnetic chitosan fiber is characterized in that: the method comprises the following steps:

(1) preparing a chitosan solution: continuously stirring chitosan and distilled water under heating condition to make chitosan powder uniformly suspended in water, adding acetic acid solution, and continuously stirring for 1-2 hr; standing or decompressing to remove air bubbles in the system to obtain a chitosan solution;

(2) preparing a chitosan fiber material: preparing a chitosan fiber material by using a wet spinning technology, selecting a saturated copper sulfate solution as a coagulating bath, and obliquely suspending a spinning needle above the surface of the coagulating bath; the chitosan solution continuously falls into the coagulating bath due to viscosity, and is drawn by a roller to pass through the coagulating bath for forming; the fiber after primary molding is kept in a coagulating bath for 8-12min to ensure complete molding;

(3) hydrothermal reaction pretreatment: firstly, Fe is prepared²⁺With Fe³⁺The mixed iron ion solution of (4); the content of magnetic particles in a finished product is regulated and controlled by regulating and controlling the concentration of the mixed iron ion solution, so that the strength of magnetism is regulated and controlled; soaking a certain amount of chitosan fiber in the solution for 2d, then replacing the same amount of the chitosan fiber, and continuing soaking for 2d to ensure that the mixed iron ion solution fully enters pores in the gel fiber to obtain the fiber subjected to pretreatment;

(4) preparing magnetic chitosan fiber: and (3) preparing the magnetic chitosan fiber by using a hydrothermal method, putting the fiber prepared in the step (3) into a sodium hydroxide solution, reacting for 8-10s, immediately taking out after the reaction, and washing the fiber in distilled water to be neutral to obtain the magnetic chitosan fiber.

2. The method for preparing a magnetic chitosan fiber according to claim 1, wherein: in the step (1), the mass ratio of the chitosan to the acetic acid is (8-10): (1.8-2.0), and the concentration of the acetic acid solution is (0.036-0.040) g/ml.

3. The method for preparing a magnetic chitosan fiber according to claim 1, wherein: the concentration of the chitosan solution obtained in the step (1) is 6.0-7.0 wt%.

4. The method for preparing a magnetic chitosan fiber according to claim 1, wherein: the condition of the step (1) is that the water bath is stirred at the temperature of 40 ℃.

5. The method for preparing a magnetic chitosan fiber according to claim 1, wherein: in the step (2), the temperature of the saturated copper sulfate solution coagulation bath is 70 ℃, the spinning needle head is a flat-head stainless steel needle head, and chitosan is provided by using an injection pump and a gear pump.

6. The method for preparing a magnetic chitosan fiber according to claim 1, wherein: in the step (2), the formed fiber is stored in a saturated copper sulfate solution at 25 ℃.

7. The method for preparing a magnetic chitosan fiber according to claim 1, wherein: in the step (3), Fe is mixed in the iron ion solution²⁺Ions with Fe³⁺The mass ratio of ions is 1: 2.

8. the method for preparing a magnetic chitosan fiber according to claim 1, wherein: in the step (4), the pH value of the sodium hydroxide solution is higher than 14 at the temperature of 80 ℃.

Technical Field

The invention relates to the field of organic polymer materials, in particular to a magnetic chitosan fiber and a preparation method thereof.

Background

Chitosan (Chitosan), a linear polysaccharide based on natural chitin. Chitin (Chitin) is the only basic polysaccharide existing in large quantities in nature, and is the second most natural organic high molecular compound which is second only to cellulose in nature. Generally, chitosan is called when the deacetylation degree of chitin is more than 55%.

The chitosan molecule has a complex double-helix structure, contains a large amount of hydroxyl and amino, can coordinate with heavy metal ions to form a complex, and can also have an effect on certain specific small molecules. In addition, amino, hydroxyl, oxygen bridge and pyran ring active group rich in electrons in the molecular structure of the chitosan can be subjected to various chemical and biological modifications to form derivatives with different physicochemical properties and functional characteristics. The chitosan can be dissolved in dilute acid, and spherical, microspherical, fibrous and other materials can be obtained through a specific forming mode.

Therefore, chitosan and its derivatives have been one of the research hotspots in the last decade, and the application field thereof is also continuously expanded, and there is a huge potential market. The chitosan has no toxicity, good biocompatibility, good degradability and good antibacterial performance, and can be widely applied to the fields of medicine, environmental protection, textile, food and cosmetic industries and the like.

Ferroferric oxide is a natural inorganic magnetic material which widely exists in the natural world and is widely applied from ancient times to present. Usually black powdered crystals or a bulk solid obtained by sintering. When the particle size of the ferroferric oxide powder is small enough, a magnetofluid material is generated. Has certain fluid property while having magnetism. The preparation is generally carried out by a hydrothermal method. The magnetic fiber is prepared by doping or adsorbing magnetic powder (such as ferroferric oxide) into chemical fiber or cotton-flax fiber. The preparation method has the problems of environmental pollution, easy separation of magnetic particles and the like.

Disclosure of Invention

The invention aims to provide a magnetic chitosan fiber and a preparation method thereof, which solve the problems that the preparation process of a chemical fiber-based magnetic fiber material in the prior art has great damage to the environment pollution and magnetic particles in a cotton-flax fiber-based magnetic fiber are easy to be separated and lost along with time, and reduce the synthesis difficulty of the fiber.

In order to achieve the purpose, the technical scheme provided by the invention is as follows:

a preparation method of magnetic chitosan fiber comprises the following steps:

(1) preparing a chitosan solution: continuously stirring chitosan CS and distilled water under heating condition to make chitosan powder uniformly suspended in water, adding acetic acid solution, and continuously stirring for 1-2 hr; standing or decompressing to remove bubbles in the system to obtain a CS solution;

(2) preparing a chitosan fiber material: preparing a chitosan fiber material by using a wet spinning technology, selecting a saturated copper sulfate solution as a coagulating bath, and obliquely suspending a spinning needle above the surface of the coagulating bath; the chitosan solution continuously falls into the coagulating bath due to viscosity, and is drawn by a roller to pass through the coagulating bath for forming; the fiber after primary molding is kept in a coagulating bath for 8-12min to ensure complete molding;

(3) hydrothermal reaction pretreatment: firstly, Fe is prepared²⁺With Fe³⁺The mixed iron ion solution of (4); the content of magnetic particles in a finished product is regulated and controlled by regulating and controlling the concentration of the mixed iron ion solution, so that the strength of magnetism is regulated and controlled; soaking a certain amount of chitosan fiber in the solution for 2d, then replacing the same amount of the chitosan fiber, and continuing soaking for 2d to ensure that the mixed iron ion solution fully enters pores in the gel fiber to obtain the fiber subjected to pretreatment;

(4) preparing magnetic chitosan fiber: and (3) preparing the magnetic chitosan fiber by using a hydrothermal method, putting the fiber prepared in the step (3) into a sodium hydroxide solution, reacting for 8-10s, immediately taking out after the reaction, and washing the fiber in distilled water to be neutral to obtain the magnetic chitosan fiber.

In the step (1), the mass ratio of the chitosan to the acetic acid is (8-10): (1.8-2.0), and the concentration of the acetic acid solution is (0.036-0.040) g/ml.

The concentration of the CS solution obtained in the step (1) is 6.0-7.0 wt%.

The condition of the step (1) is that the water bath is stirred at the temperature of 40 ℃.

In the step (2), the temperature of the saturated copper sulfate solution coagulation bath is 70 ℃, the spinning needle head is a flat-head stainless steel needle head, and chitosan is provided by using an injection pump and a gear pump.

In the step (2), the formed fiber is stored in a saturated copper sulfate solution at 25 ℃.

In the step (3), Fe is mixed in the iron ion solution²⁺Ions with Fe³⁺The mass ratio of ions is 1: 2.

in the step (4), the pH value of the sodium hydroxide solution is higher than 14 at the temperature of 80 ℃.

Compared with the prior art, the invention has the beneficial effects that:

the invention provides a magnetic chitosan fiber and a preparation method thereof, and the diameter of the magnetic chitosan fiber prepared by the invention is 2-3mm, and the length is not limited. The magnetic chitosan fiber prepared by using the nontoxic and pollution-free chitosan as the fiber material framework and the ferroferric oxide widely existing in the nature as the modifier has ferromagnetism and certain mechanical properties. The invention uses natural high molecular material as aggregate, which avoids the pollution of synthetic fiber to environment. According to the invention, ferroferric oxide particles generated in situ are uniformly wrapped in chitosan fibers, so that compared with the ferroferric oxide particles loaded on the surface of a cotton-flax material, the ferroferric oxide particles can effectively reduce loss and reduce the synthesis difficulty and cost. The invention can be prepared by wet spinning and hydrothermal reaction, and has simple preparation process, easy control and low cost.

Drawings

FIG. 1: left: the macroscopic morphology of the chitosan fiber is shown (before modification), and the right: magnetic CS functional composite fiber.

FIG. 2: section (200 μm) of chitosan fiber before modification.

FIG. 3: the chitosan fiber before modification has micropores for accommodating the mixed iron ion solution and the ferroferric oxide particles (500 mu m) generated after modification.

FIG. 4: section (50 μm) of the magnetic chitosan functional composite fiber prepared in example 1.

FIG. 5: and (3) an effect graph of the magnetic chitosan fiber attracted by a magnet.

FIG. 6: infrared image of magnetic chitosan functional composite fiber prepared in example 1.

FIG. 7: XRD characterization pattern of the magnetic chitosan functional composite fiber prepared in example 1.

Detailed Description

The present invention will be described in further detail with reference to specific examples. The following examples are intended to illustrate the invention only and are not intended to limit the scope of the invention.

Example 1

(1) Preparing a chitosan solution:

chitosan powder was uniformly suspended in water by continuously stirring 9.0g of Chitosan (CS) with 100mL of distilled water at 40 ℃, and acetic acid solution was added thereto for 1.5 hours with continuous stirring. The stirring in the water bath may be replaced by a means for achieving the same conditions, and the acetic acid solution is a uniform solution of 1.9g of acetic acid and 50 mL. And (3) standing or decompressing to remove bubbles in the system to obtain the CS solution with the concentration of 6.0-7.0 wt%.

(2) Preparing a chitosan fiber material:

the chitosan fiber material is prepared by using a wet spinning technology. Saturated copper sulfate solution was selected as the coagulation bath at 70 ℃. The spinning needle head is a flat-head stainless steel needle head and is obliquely suspended above the surface of the coagulating bath liquid. Chitosan is provided using a syringe pump, gear pump, or the like. The chitosan solution continuously falls into the coagulating bath due to viscosity, and is drawn by a roller to pass through the coagulating bath for forming. The fibers after the primary forming were left in the coagulation bath for 10min to ensure complete formation. The formed fibers were stored in a copper sulfate solution (saturated solution at 25 ℃).

(3) Hydrothermal reaction pretreatment:

firstly, Fe is prepared²⁺With Fe³⁺The mixed iron ion solution of (1). The solution requires a mass ratio of two ionic species of 1: 2. namely, adopting 22: ferric chloride hexahydrate and ferrous chloride tetrahydrate in 27 mass ratios are added with 80mL of distilled water to prepare a solution. Soaking a certain amount of chitosan fiber in the solution for 2d, then replacing the same amount of solution, and continuing to soak for 2 d. So that the mixed iron ion solution fully enters the pores in the gel fiber. Obtaining the fiber after the pretreatment.

(4) Preparing magnetic chitosan fiber:

the magnetic chitosan fiber is prepared by a hydrothermal method. And (3) putting the fiber in the sodium hydroxide solution with the pH value of more than 14 and the temperature of more than 80 ℃ for 10 s. Immediately after the reaction, the reaction mixture was taken out and washed to neutrality in distilled water. And obtaining the magnetic chitosan fiber.

Example 2

The difference between this example and example 1 is that in step (3), 60 mL, 100mL and 120mL of distilled water are used to prepare solutions, and the concentration of the mixed iron ion solution is controlled to control the content of the magnetic particles in the finished product, so as to control the strength of magnetism. Experiments in this embodiment show that the higher the concentration of the mixed iron ion solution is, the stronger the magnetism of the finally prepared magnetic chitosan functional composite fiber is.

Example 3 characterization and testing

The magnetic chitosan fiber prepared in example 1 was verified. As can be seen from fig. 2, the chitosan fiber obtained by the method for preparing chitosan fiber described in example 1 is a gel fiber (fig. 2) having many micropores for accommodating the mixed iron ion solution and the modified ferriferrous oxide particles (fig. 3). Ferroferric oxide is uniformly filled in the microporous structure of the fiber (figure 4). The finally prepared chitosan functional composite fiber has ferromagnetism (figure 5).

As can be seen from FIG. 6, the IR spectrum of this example shows that the IR absorption peak is much weaker than that of chitosan raw material and chitosan fiber, because the molecular chain of chitosan is broken and a large amount of active groups (-NH2, -OH) are lost due to the relatively severe hydrothermal reaction conditions. Although the chitosan molecules are seriously damaged, the chitosan fibers can still coat the ferroferric oxide particles, so that the damage is considered to have no influence on the performance of the final product. The XRD representation image of figure 7 shows that the molecular weight is reduced sharply due to the breakage of chitosan molecular chains, and the normal crystal face of chitosan is interfered because a large number of ferroferric oxide particles are inserted into a chitosan molecular layer. The crystallinity of chitosan is severely reduced. The crystallization peaks of ferroferric oxide appear at 30.1, 35.5, 43.2, 57.2 and the like, and the success of the combination is proved.

The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention in any way, and any person skilled in the art can make any simple modification, equivalent replacement, and improvement on the above embodiment without departing from the technical spirit of the present invention, and still fall within the protection scope of the technical solution of the present invention.