Thermochromic alginate fiber and preparation method thereof

Abstract

The invention belongs to the technical field of alginate fiber functional composite materials, and particularly relates to thermochromic alginate fibers and a preparation method thereof.The preparation method comprises the steps that a sodium alginate aqueous solution and a thermochromic microcapsule aqueous solution are mixed and stirred to form a uniform solution, defoaming treatment is conducted, and a spinning solution is obtained; the spinning solution is sprayed out of trickles through spinning holes, the trickles are solidified into filaments through a coagulating bath and shaped through a stretching bath in sequence, obtained fibers are subjected to filament separation, washing and drying in ethyl alcohol, and the thermochromic alginate fibers are obtained. According to the preparation method disclosed by the invention, the alginate fiber is endowed with high-sensitivity discoloration performance, and the strength of the alginate fiber is also remarkably improved; the preparation method is convenient to operate, simple in preparation condition, low in production cost and easy for batch and large-scale production, and has a good industrial production basis; the thermochromic alginate fiber prepared by the method has a wide application prospect in the aspects of intelligent textiles, radiation refrigeration, wearable equipment and the like.

Description

Technical field:

[0001] The invention belongs to the technical field of seaweed fiber functional composite materials, and in particular relates to a thermochromic seaweed fiber and a preparation method thereof. Background technology:

[0002] Color-changing fiber is a new type of functional fiber with great added value and benefits. It not only plays an important role in the field of security and anti-counterfeiting, but also has great demand in the textile field. With the development of the economy and the progress of social spiritual and material civilization, people's requirements for the functionalization and color diversification of fiber textiles are increasing, and color-changing fiber can just meet this demand. So far, researchers have realized the preparation of intelligent color-changing fibers based on various color-changing mechanisms such as photochromism, electrochromism, thermochromism, and mechanical color-changing through a variety of technologies (including dip coating, electrospinning, extrusion, etc.). However, these fibers still face problems such as non-renewable, poor flame retardancy, poor color controllability, and complex preparation process.

[0003] Seaweed fiber is a natural biomass regenerated fiber made from brown algae, which is abundant in the ocean. It is refined and refined to obtain alginate polysaccharides, and then produced through wet spinning deep processing technology. It has the characteristics of being environmentally friendly, non-toxic, flame retardant, biocompatible, and having abundant raw material sources. In recent years, it has attracted the favor of more and more scientific researchers and consumers, and has become a new type of green fiber material that is developing rapidly. However, the color of the seaweed fiber currently developed is still single, and the thermochromic function has not yet been realized. Summary of the invention:

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art, provide a thermochromic seaweed fiber and a preparation method thereof, make a breakthrough in the process of configuring the spinning solution, and utilize the hydrogen bond interaction between the seaweed fiber and the thermochromic microcapsule to make the two closely combined. The method not only improves the strength of the seaweed fiber, but also gives the seaweed fiber the color-changing performance, and at the same time has the advantages of low cost, simple and efficient, and can be mass-produced.

[0005] In order to achieve the above object, the present invention provides a method for preparing thermochromic seaweed fiber, comprising the following steps:

[0006] (1) Preparation of thermochromic microcapsules by in-situ polymerization: Crystal violet lactone, bisphenol A and tetradecanol were mixed, heated to 70°C, and stirred for 2 hours; cooled to room temperature to obtain a thermochromic compound; melamine, formaldehyde and distilled water were mixed, heated to 70°C, and the pH value was adjusted to 9.0 with 0.1 mol / L NaOH, and stirred for 1 hour to obtain a prepolymer solution; the thermochromic compound was prepared into an aqueous solution, styrene maleic anhydride was added, and stirred in a 60°C water bath for 30 minutes to form a white emulsion; then the white emulsion was heated to 75°C, and the prepolymer solution was added dropwise to the emulsion; then the pH value was adjusted to 4.0 with a 10wt% citric acid aqueous solution and stirred for 3 hours; then the pH value of the system was adjusted to 7.0, cooled, filtered, washed and dried to obtain thermochromic microcapsules;

[0007] (2) mixing the sodium alginate aqueous solution and the thermochromic microcapsule aqueous solution to form a uniform solution, and performing a degassing treatment to obtain a spinning solution;

[0008] (3) The spinning solution is ejected into a thin stream through a spinning hole, and is solidified into filaments in a coagulation bath and fixed in a stretching bath in sequence. The obtained fibers are separated in ethanol, washed and dried to obtain thermochromic seaweed fibers.

[0009] The mass percentage concentration of sodium alginate in the sodium alginate aqueous solution is 1.0% to 8.0%.

[0010] The thermochromic microcapsule aqueous solution is prepared by mixing thermochromic microcapsules with water in a mass ratio of 1:1 to 30.

[0011] The sodium alginate aqueous solution and the thermochromic microcapsule aqueous solution are mixed in a volume ratio of 10:1-5.

[0012] The stirring time in step (2) is 2 to 24 hours, and the stirring rate is 100 to 1000 r / min.

[0013] The degassing treatment is static degassing for 8 to 24 hours.

[0014] The coagulation bath is a calcium chloride aqueous solution with a mass percentage concentration of 2% to 8% and a temperature of 10°C to 40°C;

[0015] The stretching bath is a calcium chloride aqueous solution with a mass percentage concentration of 1% to 6% and a temperature of 10°C to 40°C.

[0016] The present invention also provides thermochromic seaweed fiber prepared by the above preparation method, which is highly sensitive to the rise and fall of ambient temperature and can undergo obvious color change reaction during the temperature rise and fall process. It is gray below 30°C and white above 30°C.

[0017] The invention is based on sodium alginate, utilizes wet spinning to introduce thermochromic microcapsules into the alginate fiber, and endows the alginate fiber with thermochromic function.

[0018] Compared with the prior art, the present invention has the following beneficial effects: a novel thermochromic seaweed fiber and a preparation method thereof are proposed, and thermochromic microcapsules are added to the spinning solution, which not only endows the seaweed fiber with high-sensitivity color-changing performance, but also significantly increases the strength of the seaweed fiber, indicating that the combination of the seaweed fiber and the thermochromic microcapsules has a synergistic effect; the preparation method thereof is easy to operate, has simple preparation conditions, has low production cost, is easy to mass-produce, and has a good industrial production foundation; the thermochromic seaweed fiber prepared by the present invention has broad application prospects in intelligent textiles, radiation refrigeration, wearable devices, etc. Description of the drawings:

[0019] Figure 1 This is a scanning electron microscope photograph of the thermochromic microcapsules prepared in Example 1 of the present invention.

[0020] Figure 2 This is a scanning electron microscope photograph of the surface of the thermochromic seaweed fiber prepared in Example 1 of the present invention.

[0021] Figure 3 This is a photograph of the strength test results of a single fiber of the thermochromic seaweed fiber prepared in Example 1 of the present invention.

[0022] Figure 4 This is a diagram showing the color change experimental results of the thermochromic seaweed fiber prepared in Example 1 of the present invention, wherein a is a photo at 10°C and 30°C; b is a photo of the fiber being heated by hand to change its color. Specific implementation method:

[0023] The present invention is further described in detail below through embodiments in conjunction with the accompanying drawings.

[0024] Embodiment 1:

[0025] The present invention relates to a method for preparing thermochromic seaweed fiber, and the specific steps are as follows:

[0026] (1) Preparation of thermochromic microcapsules: 1 g of crystal violet lactone, 4 g of bisphenol A and 70 g of tetradecanol were mixed, heated to 70°C, stirred for 2 hours, and cooled to room temperature to obtain a thermochromic compound; 2 g of melamine, 3.86 g of formaldehyde solution and 22 ml of distilled water were added to a three-necked flask, heated to 70°C, and the pH value was adjusted to 9.0 with 0.1 mol / L NaOH solution, and stirred for 1 hour to obtain a prepolymer solution; 50 g of water was added to the thermochromic compound to prepare an aqueous solution, 0.5 g of styrene maleic anhydride was added, and the mixture was emulsified and stirred in a 60°C water bath for 30 minutes to form a white emulsion; the white emulsion was then heated to 75°C, and the prepolymer solution was added dropwise to the emulsion; the pH value was then adjusted to 4.0 with a 10 wt% citric acid aqueous solution and stirred for 3 hours; and 0.1 mol / L NaOH solution, adjusting the pH value of the system to 7.0, cooling, filtering, washing and drying to obtain thermochromic microcapsules;

[0027] (2) Preparing a thermochromic microcapsule aqueous solution: 2 g of thermochromic microcapsules were mixed with 18 g of water to prepare a thermochromic microcapsule aqueous solution;

[0028] (3) preparing a spinning solution: preparing 100 g of a sodium alginate aqueous solution having a mass percentage concentration of 4%, and mixing it with the thermochromic microcapsule aqueous solution obtained in step (2), stirring it at 20° C. and 300 r / min for 24 h, and then standing it for degassing for 24 h to obtain a spinning solution;

[0029] (4) Preparation of thermochromic seaweed fibers: The spinning solution is extruded through a spinneret, solidified into filaments in a calcium chloride coagulation bath having a mass percentage concentration of 4%, and the temperature of the coagulation bath water tank is maintained at 20°C, and then fixed in a calcium chloride stretching bath having a mass percentage concentration of 4%, and the temperature of the stretching bath water tank is maintained at 20°C. The obtained fibers are separated in an ethanol aqueous solution having a mass concentration of 95%, washed and dried to obtain thermochromic seaweed fibers.

[0030] Embodiment 2:

[0031] The present invention relates to a method for preparing thermochromic seaweed fiber, and the specific steps are as follows:

[0032] (1) Preparation of thermochromic microcapsules: The specific steps are the same as those in Example 1;

[0033] (2) Preparing a thermochromic microcapsule aqueous solution: 2 g of thermochromic microcapsules were mixed with 10 g of water to prepare a thermochromic microcapsule aqueous solution; the mass ratio of the thermochromic microcapsules to water was 1:5;

[0034] (3) preparing a spinning solution: preparing 100 g of a sodium alginate aqueous solution with a mass percentage concentration of 6%, and mixing it with the thermochromic microcapsule aqueous solution of step (2), stirring it at 20° C. and 300 r / min for 24 h, and standing it for degassing for 24 h to obtain a spinning solution;

[0035] (4) Preparation of thermochromic seaweed fibers: The spinning solution is extruded through a spinneret, solidified into filaments in a calcium chloride coagulation bath having a mass percentage concentration of 6%, and the temperature of the coagulation bath water tank is maintained at 20°C, and then fixed in a calcium chloride stretching bath having a mass percentage concentration of 6%, and the temperature of the stretching bath water tank is maintained at 20°C. The obtained fibers are separated in an ethanol aqueous solution having a mass percentage concentration of 95%, washed and dried to obtain thermochromic seaweed fibers.

[0036] Embodiment 3:

[0037] The present invention relates to a method for preparing thermochromic seaweed fiber, and the specific steps are as follows:

[0038] (1) Preparation of thermochromic microcapsules: The specific steps are the same as those in Example 1;

[0039] (2) Preparing a thermochromic microcapsule aqueous solution: 2 g of thermochromic microcapsules were mixed with 10 g of water to prepare a thermochromic microcapsule aqueous solution;

[0040] (3) preparing a spinning solution: preparing 100 g of an aqueous solution of sodium alginate with a mass percentage concentration of 8%, and mixing it with the aqueous solution of thermochromic microcapsules prepared in step (2), stirring the mixture at 20° C. and 300 rpm for 24 h, and allowing the mixture to stand for degassing for 24 h to obtain a spinning solution;

[0041] (4) Preparation of thermochromic seaweed fibers: The spinning solution is extruded through a spinneret, solidified into filaments in a calcium chloride coagulation bath having a mass percentage concentration of 8%, and the temperature of the coagulation bath water tank is maintained at 20°C, and then fixed in a calcium chloride stretching bath having a mass percentage concentration of 8%, and the temperature of the stretching bath water tank is maintained at 20°C. The obtained fibers are separated in an ethanol aqueous solution having a mass percentage concentration of 95%, washed and dried to obtain thermochromic seaweed fibers.

[0042] Embodiment 4:

[0043] The present invention relates to a method for preparing thermochromic seaweed fiber, and the specific steps are as follows:

[0044] (1) Preparation of thermochromic microcapsules: The specific steps are the same as those in Example 1;

[0045] (2) Preparing a thermochromic microcapsule aqueous solution: 2 g of thermochromic microcapsules were mixed with 18 g of water to prepare a thermochromic microcapsule aqueous solution;

[0046] (3) preparing a spinning solution: preparing 100 g of a sodium alginate solution with a mass percentage concentration of 2%, and mixing it with an aqueous solution of thermochromic microcapsules, stirring it at 20° C. and 300 r / min for 24 h, and standing it for degassing for 24 h to obtain a spinning solution;

[0047] (4) Preparation of thermochromic seaweed fibers: The spinning solution is extruded through a spinneret, solidified into filaments in a calcium chloride coagulation bath having a mass percentage concentration of 2%, and the temperature of the coagulation bath water tank is maintained at 20°C, and then fixed in a calcium chloride stretching bath having a mass percentage concentration of 2%, and the temperature of the stretching bath water tank is maintained at 20°C. The obtained fibers are separated in an ethanol aqueous solution having a mass percentage concentration of 95%, washed and dried to obtain thermochromic seaweed fibers.

[0048] Embodiment 5:

[0049] This example relates to the characterization and performance testing of the thermochromic seaweed fiber prepared in Example 1.

[0050] The thermochromic microcapsules and thermochromic seaweed fibers prepared in Example 1 were characterized by scanning electron microscopy. Figure 1 and Figure 2 shown.

[0051] from Figure 1 It can be seen that the thermochromic microcapsules are spherical and the particle size distribution is between 1 and 10 microns.

[0052] from Figure 2 It can be seen that the surface of the thermochromic seaweed fiber presents spherical protrusions, indicating that the thermochromic microcapsules are successfully compounded into the seaweed fiber.

[0053] The single fiber strength test of the thermochromic seaweed fiber in Example 1 was carried out, and the pure seaweed fiber was used as a comparison. The results are as follows: Figure 3 As shown. Figure 3 It can be seen that compared with pure seaweed fiber, thermochromic seaweed fiber has higher strength, while the elongation is basically the same as that of pure seaweed fiber.

[0054] The thermochromic algae fiber of Example 1 was subjected to a color change test. The thermochromic algae fiber was placed in an environment of 10°C and 30°C for 1 minute, and the color change was recorded by taking photos. The results are shown in FIG. Figure 4 As shown in a. Figure 4 a It can be seen that at 10°C, the thermochromic seaweed fiber is gray, and at 30°C, the thermochromic seaweed fiber is white.

[0055] At 20℃, hold one end of the thermochromic seaweed fiber with your hand and observe the color change of the fiber. Figure 4As shown in b, hold it for 20 seconds, and the end held by the hand turns white due to the increase in temperature. The end not held by the hand remains gray because it does not heat up.

[0056] The above description shows that the thermochromic seaweed fiber prepared by the present invention is highly sensitive to the rise and fall of the ambient temperature, and can undergo obvious color change reaction during the temperature rise and fall process. It is gray below 30°C and white above 30°C.

Claims

1. A method for preparing thermochromic seaweed fiber, characterized in that: The following steps are involved: (1) mixing the sodium alginate aqueous solution and the thermochromic microcapsule aqueous solution to form a uniform solution, and performing a degassing treatment to obtain a spinning solution; (2) The spinning solution is ejected into a thin stream through a spinning hole, and is solidified into filaments in a coagulation bath and fixed in a stretching bath in sequence. The obtained fibers are separated in ethanol, washed and dried to obtain thermochromic seaweed fibers.

2. The method for preparing thermochromic seaweed fiber according to claim 1, characterized in that: The mass percentage concentration of sodium alginate in the sodium alginate aqueous solution is 1.0% to 8.0%.

3. The method for preparing thermochromic seaweed fiber according to claim 1, characterized in that: The thermochromic microcapsule aqueous solution is prepared by mixing thermochromic microcapsules with water in a mass ratio of 1:1 to 30.

4. The method for preparing thermochromic seaweed fiber according to claim 1, characterized in that: The sodium alginate aqueous solution and the thermochromic microcapsule aqueous solution are mixed in a volume ratio of 10:1-5.

5. The method for preparing thermochromic seaweed fiber according to claim 1, characterized in that: The stirring time in step (1) is 2 to 24 hours, and the stirring rate is 100 to 1000 r / min.

6. The method for preparing thermochromic seaweed fiber according to claim 1, characterized in that: The degassing treatment is static degassing for 8 to 24 hours.

7. The method for preparing thermochromic seaweed fiber according to claim 1, characterized in that: The coagulation bath is a calcium chloride aqueous solution with a mass percentage concentration of 2% to 8% and a temperature of 10°C to 40°C; the stretching bath is a calcium chloride aqueous solution with a mass percentage concentration of 1% to 6% and a temperature of 10°C to 40°C.

8. The method for preparing thermochromic seaweed fiber according to claim 1, characterized in that: The thermochromic microcapsules are prepared by an in-situ polymerization method, specifically: crystal violet lactone, bisphenol A and tetradecanol are mixed, heated and stirred; cooled to room temperature to obtain a thermochromic compound; melamine, formaldehyde and distilled water are mixed, heated and stirred to obtain a prepolymer solution; styrene maleic anhydride is added to the aqueous solution of the thermochromic compound, stirred to form a white emulsion; the white emulsion is heated, and the prepolymer solution is dripped into the emulsion; the pH value is adjusted; and the thermochromic microcapsules are obtained through cooling, filtering, washing and drying.

9. The thermochromic seaweed fiber prepared by the preparation method according to any one of claims 1 to 8, characterized in that: A color change reaction occurs during the heating and cooling process.

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