CN109972233A - Preparation method of biodegradable alginate fiber with high strength and high toughness - Google Patents

Abstract

The invention discloses a preparation method of biodegradable alginate fiber with high strength and high toughness, and belongs to the technical field of preparation of alginate fiber. The preparation method includes: firstly dissolving the raw materials sodium alginate and cellulose ether in deionized water to prepare a blended silk solution A; then preparing a polypolysaccharide nano-dispersion, and mixing the obtained blended silk solution A with the obtained polysaccharide nanometer dispersion The dispersion is fully mixed, and Tween 20, monoglyceride or a compound of the two are added to it, and the blended silk solution B is obtained after stirring and defoaming in turn; finally, the blended silk solution B is placed in a coagulation bath. , Using wet spinning process, alginate fiber is obtained after drawing, washing, soaking and drying. The invention has the beneficial effects of simple and easy-to-control process, energy saving and environmental protection, good product quality and the like.

Description

Preparation method of biodegradable alginate fiber with high strength and high toughness

technical field

The invention relates to the technical field of preparation of alginate fibers, in particular to a method for preparing high-strength and high-toughness seaweed fibers by selecting green and environmentally friendly biological materials.

Background technique

my country is the largest country in seaweed farming and seaweed processing. Seaweed farming and processing accounts for more than 70% of the world's total. Seaweed polysaccharide has broad prospects for development and application. Based on cheap seaweed polysaccharide, a large number of products with important value and high added value can be produced. The natural polysaccharide sodium alginate extracted from seaweed can be used as raw material to prepare alginate fiber by wet spinning process. The study found that alginate fiber has many excellent properties, such as high hygroscopicity, hemostasis, high oxygen permeability, coagulation Adhesive blocking, biodegradability and biocompatibility, etc., can be used to make non-woven fabrics and fabrics, used in medical gauze, bandages, dressings and masks, etc. However, alginate fiber has low breaking strength and small breaking elongation, and is easy to break in the spinning process, which is a typical brittle fracture, which greatly limits its application range.

Based on the above technical problems in the prior art, researchers in this field focus more on related research to improve the mechanical properties of alginate fibers, and the method for improving the mechanical properties of alginate fibers is mainly by modifying alginic acid. The modification methods mainly include physical modification and chemical modification. Among them, physical modification mainly includes blending, filling and other methods, and chemical modification mainly includes copolymerization, grafting and other methods.

The above related research reports mainly include: adding inorganic nanoparticles to the spinning dope, such as adding nano-silica, nano-montmorillonite, nano-titanium dioxide, nano-aluminum hydroxide, etc., and preparing alginic acid/inorganic nano-particles by wet spinning The particle composite fiber utilizes the excellent properties of inorganic nanoparticles such as high strength, high stiffness, and high specific surface area to enhance the tensile breaking strength of alginate fibers. Some use epichlorohydrin to prepare cross-linked alginate fibers to promote the cross-linking between alginate fibers; Ion exchange with calcium ions to modify calcium alginate fibers.

For example, CN 106012103 A discloses a preparation method of high-strength seaweed fiber, which adds nano-calcium carbonate to sodium alginate solution to obtain spinning dope, and the spinning dope is filtered and quickly defoamed, and calcium chloride is used to prepare the spinning dope. Wet spinning is carried out for coagulation bath to obtain nano primary fibers; then, the primary fibers are soaked in deionized water for 24h-72h, and then post-treated.

CN 106149099 A discloses a preparation method of high-strength seaweed fiber, which firstly prepares alginate spinning solution, then blends or crosslinks alginate with polyvinyl alcohol to obtain alginate spinning solution, High-strength seaweed fibers are prepared after spinning, microwave drying and other steps.

Although the above methods can effectively improve the mechanical properties of seaweed fibers, they only focus on improving the strength of seaweed fibers and lack consideration of the green environmental protection of the materials used. For example, the addition of inorganic nanoparticles may be biocompatible to alginate fibers. It will have adverse effects on its hygroscopicity and degradability, and will also affect other properties such as moisture absorption and moisturizing.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a biodegradable preparation method of alginate fiber with high strength and high toughness, which not only reduces the problem of environmental pollution caused in the preparation process, but also improves the mechanical properties of alginate fiber at the same time.

To achieve the above object, the present invention has adopted the following technical solutions:

A method for preparing a biodegradable alginate fiber, comprising the steps of:

a Dissolve the raw materials sodium alginate and cellulose ether in deionized water, the mass ratio of the sodium alginate and the cellulose ether is 3-5:1, and configure the blended silk solution with a mass percentage of 6-12% A;

b. Weigh a certain amount of polysaccharide nanocrystals, dissolve them in deionized water, and ultrasonically disperse them at 25°C under the power of 800-1000w for 2-3 hours to obtain polysaccharide nano-dispersion;

c. Fully mix the blended silk solution A obtained in step a and the polypolysaccharide nano-dispersion obtained in step b, add substance D with a mass fraction of 0.05 to 0.5%, and then stir and defoam in turn to obtain a blended spinning solution B. ;

d placing the blended spinning solution B described in step c in a coagulation bath, and adopting a wet spinning process to obtain alginate fibers after drawing, washing, soaking and drying;

The cellulose ether is water-soluble anionic or non-ionic, and the substance D is Tween 20, monoglyceride or a combination of the two.

The technical effects directly brought about by the preferred technical solution are:

(1) The present invention utilizes the advantages of large specific surface area, good biocompatibility, environmental friendliness, and reproducibility of polysaccharide nanocrystals. After adding polysaccharide nanocrystals to alginic acid matrix, its special orientation, three-dimensional network structure and interface The structure can not only form a strong hydrogen bond with the alginate matrix, bear the load during the stretching process of the alginate fiber, but also act as a rivet to prevent the spread of cracks and make the force spread in different directions, thereby improving the alginate fiber. The strength and toughness of the material; in addition, the addition of cellulose ether can form molecular chain entanglement with alginic acid, which can effectively improve the tensile toughness of alginate fibers. Therefore, by controlling the amount of added polysaccharide nanocrystals and cellulose ether, Thus, the balance between strength and toughness can be adjusted to meet the different application requirements of alginate fibers.

(2) The selected raw materials of the present invention do not use any harmful chemicals, all are green and degradable environmental protection materials, and do not have any damage to the green performance of alginic acid.

(3) The process of the invention is simple, the processing energy consumption is low, and the invention can be well applied to the industrialized continuous production of alginate fibers.

In order to facilitate understanding of the present invention, the reaction mechanism of the above technical solution is further described below with reference to FIG. 4 .

The cellulose ether macromolecules are added to the alginic acid matrix, and the alginic acid and the cellulose ether macromolecules are entangled with each other and form intermolecular hydrogen bonds. It is more complex and forms a three-dimensional structure. After the calcium chloride coagulation bath, the alginic acid molecules are rearranged and combined, and the G unit in the macromolecule is chelated with calcium ions to form an eggshell structure. The macromolecules are relatively closely arranged, and the entanglement is reduced. At this time, cellulose ether macromolecules and polysaccharide nanocrystals play a crucial role in its tensile properties. Cellulose ether macromolecules can play a role in entanglement between alginic acid macromolecules. When stretching, when the weak section of the alginate fiber is broken, the macromolecules of cellulose ether still play the role of supporting the skeleton. There are hydrogen bonds, and polypolysaccharide nanocrystals have hydrogen bonds with two macromolecules in the matrix. They bear the load during the stretching process of alginate fibers, and can play the role of rivets to prevent the spread of cracks and make the alginate fibers. The force spreads in different directions, and the two act synergistically to improve the strength and toughness of the alginate fiber.

As a preferred solution of the present invention, the water-soluble anionic cellulose ether is carboxymethyl cellulose, and the non-ionic cellulose ether is methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose or hydroxypropyl cellulose propyl methylcellulose.

As another preferred embodiment of the present invention, the above-mentioned cellulose ether is hydroxypropyl methylcellulose.

Further, in step a, the mass ratio of above-mentioned sodium alginate and cellulose ether is 4:1.

Further, in step b, the above-mentioned polysaccharide nanocrystals are selected from cellulose nanocrystals, starch nanocrystals or chitosan nanocrystals.

Further, the above polysaccharide nanocrystals are cellulose nanocrystals.

Further, the preparation step of the coagulation bath in step d is as follows: dissolving a certain amount of calcium chloride in distilled water to prepare an aqueous calcium chloride solution with a mass percentage of 4-6%, and the temperature of the coagulation bath is 15-30°C.

Further, in step d, a three-stage drafting process is adopted, the drafting multiple of each stage is 1.2-1.5 times, the temperature of washing is 15-50 °C, and the temperature of drying is 50-70 °C.

Compared with the prior art, the present invention brings the following beneficial technical effects:

First of all, from the selection of raw materials, the present invention selects the combination of polypolysaccharide nanocrystals and cellulose ether, and the alginate fiber prepared from this is a green product, which can be used to make various needles, woven fabrics and non-woven fabrics, not only can It is used for medical gauze, bandages and dressings, etc. It has the characteristics of biodegradability and compatibility, promotes wound healing, reduces wound pain, etc. It provides new medical materials for the medical field, and adds new green fiber materials for wearing fabrics , greatly improving the added value of marine products, and at the same time, by making full use of marine resources, alleviating problems such as lack of synthetic fiber resources and environmental pollution.

In addition, in the preparation method, an entangled network is formed between cellulose ether macromolecules and alginic acid macromolecules, the structure of polysaccharide nanocrystals in the matrix includes orientation, three-dimensional network structure and interface structure, and fibers are added to the alginic acid matrix. After the plain ether and the polysaccharide nanocrystals form a special three-dimensional structure, they can bear the load during the stretching process of the alginate fiber. The simple ether macromolecules play the role of entanglement and fracture buffer, and the synergistic effect of the two can greatly improve the strength and toughness of alginate fiber materials. force between the two.

Finally, compared with the prior art, the present invention has the beneficial effects of simple and easy-to-control process, energy saving and environmental protection, and good product quality.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings:

Fig. 1 is the tensile fracture surface view of pure alginate fiber of the present invention;

Fig. 2 is the tensile fracture surface view of the seaweed fiber prepared by following Example 3;

Fig. 3 is the X-ray diffraction pattern of pure seaweed fiber and embodiment 3;

Figure 4 is a schematic diagram of the reaction mechanism of the present invention.

Detailed ways

The present invention proposes a method for preparing biodegradable alginate fibers with high strength and high toughness. In order to make the advantages and technical solutions of the present invention clearer and clearer, the present invention is described in detail below with reference to specific examples.

Note: The raw materials required for each of the following examples can be purchased through commercial channels.

Cellulose ethers are mainly anionic and non-ionic, anionic: carboxymethyl cellulose (CMC);

Non-ionic: methyl cellulose (MC), hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), hydroxypropyl methyl cellulose (HPMC);

The polysaccharide nanocrystals are selected from cellulose nanocrystals, starch nanocrystals or chitosan nanocrystals.

Example 1:

The preparation method of biodegradable alginate fiber with high strength and high toughness specifically comprises the following steps:

The first step, the raw material sodium alginate and cellulose ether hydroxypropyl methylcellulose are dissolved in deionized water, the mass ratio of sodium alginate and hydroxypropyl methylcellulose is 3:1, and the mass percentage obtained by configuration is 6% blended silk dope A;

Step 2: Weigh 8 wt% cellulose nanocrystals (relative to sodium alginate), dissolve them in deionized water, and ultrasonically disperse them at 25°C under 800-1000w power for 2-3 hours to obtain cellulose nanocrystals. crystal dispersion;

The third step is to fully mix the blended silk solution A obtained in the first step with the cellulose nanocrystal dispersion obtained in the second step, and add Tween 20 with a mass fraction of 0.05% to it, and then stir and defoaming in turn to obtain Blending Dope B;

The fourth step, placing the blended spinning solution B obtained in the third step in a coagulation bath, using a wet spinning process, drawing, washing, soaking in a 90wt% alcohol solution, and drying to obtain alginic acid fibers;

The temperature of the spinning dope is 15-40°C, the temperature of the coagulation bath is 15-30°C, the drafting adopts a three-stage drafting process, the multiple of each stage is 1.2-1.5 times, the temperature of the washing is 15-50°C, and the drying is carried out. Take the temperature 50 ~ 70 ℃.

Example 2:

The difference with Example 1 is: the mass ratio of sodium alginate and hydroxypropyl methylcellulose is 4:1.

Example 3:

The difference with Example 1 is: the mass ratio of sodium alginate and hydroxypropyl methylcellulose is 5:1.

Example 4:

The difference from Example 1 is: hydroxyethyl cellulose is selected for the cellulose ether, the mass ratio of sodium alginate to hydroxyethyl cellulose is 4:1, and the polysaccharide nanocrystals are selected from starch nanocrystals.

Example 5:

The difference from Example 1 is: hydroxypropyl cellulose is selected for the cellulose ether, the mass ratio of sodium alginate to hydroxypropyl cellulose is 4:1, and the polysaccharide nanocrystals are selected from chitosan nanocrystals.

Example 6:

The difference from Example 1 is that:

In the third step, the blended silk solution A obtained in the first step and the cellulose nanocrystal dispersion obtained in the second step are fully mixed, and the compound of Tween 20 and monoglyceride with a mass fraction of 0.5% is added thereto, After stirring and defoaming in turn, the blended silk solution B was obtained.

Example 7:

The difference from Example 1 is that:

The third step is to fully mix the blended silk solution A obtained in the first step with the cellulose nanocrystal dispersion obtained in the second step, and add 0.5% monoglyceride to it, and then stir and defoam in turn to obtain Blending Dope B.

Comparative Example 1:

The first step, the raw material sodium alginate is dissolved in deionized water, and the configuration obtains the alginic acid spinning solution A with a mass percentage of 6%;

Step 2: Weigh 8 wt% cellulose nanocrystals (relative to sodium alginate), dissolve them in deionized water, and ultrasonically disperse them at 25°C under 800-1000w power for 2-3 hours to obtain cellulose nanocrystals. crystal dispersion;

The third step is to fully mix the spinning solution A obtained in the first step with the cellulose nanocrystal dispersion obtained in the second step, and add Tween 20 with a mass fraction of 0.05% to it, and then stir and defoaming in turn to obtain a total of Blended silk solution B;

The fourth step, placing the blended spinning solution B obtained in the third step in a coagulation bath, using a wet spinning process, drawing, washing, soaking in a 90wt% alcohol solution, and drying to obtain alginic acid fibers;

The temperature of the spinning dope is 15-40°C, the temperature of the coagulation bath is 15-30°C, the drafting adopts a three-stage drafting process, the multiple of each stage is 1.2-1.5 times, the temperature of the washing is 15-50°C, and the drying is carried out. Take the temperature 50 ~ 70 ℃.

The alginate fibers prepared in the above-mentioned Examples 1-7 and Comparative Example 1 were tested for the following mechanical properties, wherein the test method for the main parameters was: using a single fiber tester, the fibers were fixed in a fixture, and the tensile strength of the fibers was tested. Tensile strength and elongation at break. Gauge: 10mm, stretching speed: 8mm/min. The mechanical properties of the fibers were averaged from 50 samples. The test results are shown in Table 1.

Table 1 Physical and mechanical properties of modified alginate fibers

The above table 1 further proves that the hydrogen bond between polypolysaccharide nanocrystals and alginic acid also enhances the interaction force between the two to a certain extent. As shown in Figure 1 and Figure 2, the surface of the cross section of the pure alginate fiber is smooth, and some areas are mirror-like, which is a typical brittle fracture, while in Example 3, the mirror area of the cross-section of the fiber completely disappeared, and uneven dimples appeared. , indicating that the toughness of the embodiment is enhanced. As shown in Figure 3, the crystallinity of Example 3 is stronger than that of pure alginate fiber, which explains one of the reasons for the increase in its strength.

The parts not mentioned in the present invention can be realized by referring to the prior art.

It should be noted that any equivalent manner or obvious modification manner made by those skilled in the art under the teaching of this specification shall fall within the protection scope of the present invention.

Claims (8)

1. a preparation method of biodegradable alginate fiber, is characterized in that, comprises the following steps successively: a Dissolve the raw materials sodium alginate and cellulose ether in deionized water, the mass ratio of the sodium alginate and the cellulose ether is 3-5:1, and configure the blended silk solution with a mass percentage of 6-12% A; b. Weigh a certain amount of polysaccharide nanocrystals, dissolve them in deionized water, and ultrasonically disperse them at 25°C under the power of 800-1000w for 2-3 hours to obtain polysaccharide nano-dispersion; c. Fully mix the blended silk solution A obtained in step a and the polypolysaccharide nano-dispersion obtained in step b, add substance D with a mass fraction of 0.05 to 0.5%, and then stir and defoam in turn to obtain a blended spinning solution B. ; d placing the blended spinning solution B described in step c in a coagulation bath, and adopting a wet spinning process to obtain alginate fibers after drawing, washing, soaking and drying; The cellulose ether is water-soluble anionic or non-ionic, and the substance D is Tween 20, monoglyceride or a combination of the two. 2. the preparation method of a kind of biodegradable alginate fiber according to claim 1 is characterized in that: the cellulose ether of water-soluble anionic type is carboxymethyl cellulose, and the cellulose ether of non-ionic type is methyl cellulose cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose or hydroxypropyl methylcellulose. 3. The preparation method of a biodegradable alginate fiber according to claim 2, wherein the cellulose ether is hydroxypropyl methylcellulose. 4. the preparation method of a kind of biodegradable alginate fiber according to claim 1, is characterized in that: in step a, the mass ratio of described sodium alginate and cellulose ether is 4:1. 5. the preparation method of a kind of biodegradable alginate fiber according to claim 1, is characterized in that: in step b, described polysaccharide nanocrystal is selected from cellulose nanocrystal, starch nanocrystal or chitosan Sugar Nanocrystals. 6 . The method for preparing a biodegradable alginate fiber according to claim 5 , wherein the polysaccharide nanocrystals are cellulose nanocrystals. 7 . 7. the preparation method of a kind of biodegradable alginate fiber according to claim 1, is characterized in that, the preparation step of the described coagulation bath of step d is: a certain amount of calcium chloride is dissolved in distilled water, A calcium chloride aqueous solution with a mass percentage of 4-6% is prepared, and the temperature of the coagulation bath is 15-30°C. 8. the preparation method of a kind of biodegradable alginic acid fiber according to claim 1, is characterized in that: in step d, adopts three-stage drafting process, and the multiple of each process drafting is 1.2～1.5 times , the temperature of washing is 15-50 ℃, and the temperature of drying is 50-70 ℃.