A method for preparing electromagnetic shielding fiber from sheepskin collagen by wet spinning

Abstract

A method for preparing electromagnetic shielding fibers from sheepskin collagen by wet spinning, comprising the following steps: step 1, crushing swollen sheepskin and adding the crushed product into an acetic acid solution for dissolution, extracting soluble collagen, and performing in-situ polymerization of aniline and combining with carbon nanotubes on the crushed product; step 2, dissolving the soluble collagen fibers obtained in step 1 in deionized water, ultrasonically adding aniline monomer and hydrochloric acid, performing in-situ polymerization of aniline on the crushed product, adding the crushed product into an acidified carbon nanotube dispersion, subsequently adding sodium polyacrylate, stirring, filtering, and standing for defoaming to obtain a uniform spinning solution; step 3, wet spinning, filtering and defoaming the spinning solution, and performing wet spinning to obtain composite fibers, i.e., electromagnetic shielding fibers; the wet spinning technology of the present invention is used to process sheepskin into fibers, and the processing method is simple, the effect is good, and the electromagnetic shielding effectiveness of the obtained fibers can be enhanced.

Description

Technical Field

[0001] The invention belongs to the technical field of electromagnetic shielding materials, and particularly relates to a method for preparing electromagnetic shielding fibers from sheepskin collagen by wet spinning. Background Art

[0002] With the rapid development of communication technology, electromagnetic radiation poses a potential threat to information security, human health, and the ecological environment. While metal-based electromagnetic shielding materials offer excellent electromagnetic shielding performance, they suffer from a single, primarily reflective shielding mechanism. Furthermore, metals are susceptible to corrosion, have high density, and are difficult to process, limiting their practical application. Therefore, developing new, flexible electromagnetic shielding materials with ultralight, multifunctional properties is an effective means of achieving this new shielding trend. Currently, electrospinning and wet spinning are popular methods for producing nanofibers. However, the electrospinning process is susceptible to environmental factors, with varying temperatures and humidity affecting fiber collection and creating instability. Furthermore, electrospinning requires the use of large amounts of organic solvents in the spinning solution, which are not only toxic but also disruptive to the collagen structure, causing denaturation. In contrast, wet spinning addresses these shortcomings of electrospinning. Summary of the Invention

[0003] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a method for preparing electromagnetic shielding fibers from sheepskin collagen by wet spinning. Sheepskin collagen is used as the base material, and flexible electromagnetic shielding fibers are prepared by wet spinning technology. The method has the characteristics of simple processing method, effective reduction of electromagnetic pollution, and enhanced electromagnetic shielding performance.

[0004] To achieve the above object, the technical solution adopted by the present invention is:

[0005] A method for preparing electromagnetic shielding fibers from sheepskin collagen by wet spinning, comprising the following steps:

[0006] Step 1, collagen extraction: crush an appropriate amount of swollen sheepskin and add it to a 20% acetic acid solution. Dissolve the sheepskin completely at high temperature. Stir rapidly in a water bath at 60°C for 12 hours to completely dissolve the sheepskin. Obtain collagen.

[0007] Step 2, preparation of spinning solution: 10 g of collagen obtained in step 1 was weighed and dissolved in 30 L of deionized water, ultrasonicated for 1-2 h, and aniline monomer and hydrochloric acid were added thereto to carry out in-situ polymerization of aniline. The solution was then added to 0.05-0.2 g of the acidified carbon nanotube dispersion, followed by 0.1-0.3 g of sodium polyacrylate. After stirring for 8-12 h, the solution was filtered and allowed to stand for defoaming to obtain a uniform spinning solution.

[0008] Step 3, wet spinning: 8-12 mL of the above spinning solution is taken, the spinning solution is filtered and defoamed, and wet-spinning is performed to obtain composite fibers, i.e., electromagnetic shielding fibers.

[0009] The acid skin described in step 1 is completely dissolved, the dissolution temperature is 50-70°C, and it is stirred rapidly for 10-12 hours.

[0010] The in-situ polymerization of aniline described in step 2 is specifically carried out as follows:

[0011] Add 1-3 g of aniline monomer and 10-30 mL of hydrochloric acid to the collagen solution and stir rapidly in a water bath at room temperature for 1-3 hours. Then, dissolve ammonium persulfate in an amount equal to that of aniline in 10-30 mL of deionized water and slowly add it dropwise to the three-necked flask. Stir and react in a water bath at 0-5°C for 8-10 hours. After the reaction is completed, place the solution in a refrigerator and let it stand overnight.

[0012] The acidified carbon nanotube dispersion in step 2 is acidified using concentrated sulfuric acid and concentrated nitric acid, with the ratio of carbon nanotubes:concentrated sulfuric acid:concentrated nitric acid being 1:100:33.

[0013] The wet spinning described in step 3 is specifically performed as follows: using methanol as a coagulation bath, placing the spinning solution in a 10 mL propeller, and pushing at a speed of 0.7 to 0.9 mm / min.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] The collagen used in the present invention is a renewable biomass resource and an important component of leather. Its unique helical structure makes it a good base material for constructing flexible electromagnetic shielding materials, which can avoid specific complex structural designs. At the same time, the carboxyl and amino groups on the side chains of the collagen molecules can be arranged along the direction of the electric field in the electric field as dipoles. This process will cause dielectric loss of electromagnetic waves due to the obstruction of molecular thermal motion, thereby enhancing the electromagnetic shielding effectiveness. Based on this, the present invention uses collagen extracted from sheepskin as a base material, utilizes the unique helical structure of collagen and conductive fillers to compositely construct a three-dimensional conductive network, and then spins it into fibers through wet spinning technology, thereby obtaining a flexible electromagnetic shielding material with excellent electromagnetic shielding performance, lightness and flexibility, which provides a new idea for the development of flexible electromagnetic shielding materials. The advantages are as follows:

[0016] 1) The present invention uses collagen as a flexible substrate to enhance electromagnetic loss. At the same time, the carboxyl and amino groups on the side chains of the collagen molecules can act as dipoles and align along the direction of the electric field in the electric field. This process will cause dielectric loss of electromagnetic waves due to the obstruction of molecular thermal motion, thereby enhancing electromagnetic shielding effectiveness.

[0017] 2) The present invention utilizes wet spinning technology instead of electrospinning, which can reduce or avoid the use of organic solvents in the preparation of the spinning solution and reduce damage to the collagen structure.

[0018] 3) The shielding mechanism of the fiber obtained by the present invention is mainly reflection. A large amount of electromagnetic waves contacting the fiber surface are reflected back to the environment, and a small amount of electromagnetic waves enter the fiber interior and are absorbed secondary. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Shielding effect spectra of PAAS / MWCNT / PANI / CA fibers with different MWCNT contents.

[0020] Figure 2 Shielding mechanism spectra of PAAS / MWCNT / PANI / CA fibers with different MWCNT contents.

[0021] Figure 3 This is the SEM spectrum of PAAS / MWCNT / PANI / CA composite fibers obtained by wet spinning.

[0022] Figure 4 Flowchart of the present invention. DETAILED DESCRIPTION

[0023] The present invention is described in detail below in conjunction with the implementation methods. It is necessary to point out that this embodiment is only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Technical personnel skilled in the art can make non-essential improvements and adjustments based on the content of the above invention.

[0024] See also Figure 4 , Example 1

[0025] Step 1, collagen extraction: crush an appropriate amount of swollen sheepskin and add it to a 20% acetic acid solution, and stir rapidly in a water bath at 60°C for 12 hours to completely dissolve the acid skin;

[0026] Step 2, preparation of spinning solution: add 1g of aniline monomer and 10mL of hydrochloric acid (1M) to the solution, stir rapidly in a water bath at room temperature for 1h, then dissolve 1g of ammonium persulfate (APS) initiator with the same mass as aniline in 10mL of deionized water, slowly add dropwise to a three-necked flask, stir and react at a water bath temperature of 3°C for 8h, put into a refrigerator and let it stand overnight after the reaction, acidify 0.05g of carbon nanotubes with concentrated sulfuric acid and concentrated nitric acid in a mass ratio of carbon nanotubes:concentrated sulfuric acid:concentrated nitric acid = 1:100:33; and weigh 0.2g of sodium polyacrylate and add it to the above mixture and stir; to obtain a uniform spinning solution;

[0027] Step 3, wet spinning: 10 mL of the spinning solution was filtered and defoamed, and finally wet-spinned to obtain a composite fiber; the specific parameters of the spinning were: the coagulation bath was methanol, the spinning solution was placed in a 10 mL propeller, and the propulsion speed was 0.8 mm / min; the fibers obtained by wet spinning were further woven into a fabric, and its electromagnetic shielding performance was measured to be 6 dB. Example

[0028] Step 1, collagen extraction: crush an appropriate amount of swollen sheepskin and add it to a 20% acetic acid solution, and stir rapidly in a water bath at 60°C for 12 hours to completely dissolve the acid skin;

[0029] Step 2, preparation of spinning solution: add 1g of aniline monomer and 10mL of hydrochloric acid (1M) to the solution, and stir rapidly in a water bath at room temperature for 1h; then dissolve ammonium persulfate (APS) initiator in an amount equal to that of aniline in 10mL of deionized water, slowly add the solution dropwise to a three-necked flask, stir and react in a water bath at 3°C ​​for 8h, and after the reaction is completed, place the solution in a refrigerator and let it stand overnight; acidify 0.1g of carbon nanotubes with concentrated sulfuric acid and concentrated nitric acid in a mass ratio of carbon nanotubes:concentrated sulfuric acid:concentrated nitric acid = 1:100:33, and weigh 0.2g of sodium polyacrylate and add it to the above mixture and stir to obtain a composite product; obtain a uniform spinning solution;

[0030] Step 3, wet spinning: 10 mL of the spinning solution was filtered and defoamed, and finally wet-spinned to obtain a composite fiber; the specific parameters of the spinning were: the coagulation bath was methanol, the spinning solution was placed in a 10 mL propeller, and the propulsion speed was 0.8 mm / min; the fibers obtained by wet spinning were further woven into a fabric, and its electromagnetic shielding performance was measured to be 8 dB. Example

[0031] Step 1, collagen extraction: crush an appropriate amount of swollen sheepskin and add it to a 20% acetic acid solution, and stir rapidly in a water bath at 60°C for 12 hours to completely dissolve the acid skin;

[0032] Step 2, preparation of spinning solution: add 1g of aniline monomer and 10mL of hydrochloric acid (1M) to the solution, and stir rapidly at room temperature for 1h in a water bath; then dissolve ammonium persulfate (APS) initiator in an amount equal to that of aniline in 10mL of deionized water, slowly add it dropwise to a three-necked flask, and stir in a water bath at 3°C ​​for 8h. After the reaction is completed, place it in a refrigerator and let it stand overnight: acidify 0.15g of carbon nanotubes with concentrated sulfuric acid and concentrated nitric acid in a mass ratio of carbon nanotubes:concentrated sulfuric acid:concentrated nitric acid = 1:100:33, weigh 0.2g of sodium polyacrylate and add it to the above mixture and stir to obtain a uniform spinning solution;

[0033] Step 3, wet spinning: 10 mL of the spinning solution was filtered and defoamed; finally, wet spinning was performed to produce the composite fiber. The spinning parameters were: methanol as the coagulation bath, the spinning solution placed in a 10 mL propeller, and a propulsion speed of 0.8 mm / min. The wet-spun fibers were further woven into a fabric, and the electromagnetic shielding performance was measured to be 11 dB. Example

[0034] Step 1, collagen extraction: crush an appropriate amount of swollen sheepskin and add it to a 20% acetic acid solution, and stir rapidly in a water bath at 60°C for 12 hours to completely dissolve the acid skin;

[0035] Step 2, preparation of spinning solution: add 1g of aniline monomer and 10mL of hydrochloric acid (1M) to the collagen solution, stir rapidly at room temperature for 1h in a water bath, then dissolve ammonium persulfate (APS) initiator in an amount equal to that of aniline in 10mL of deionized water, slowly add the solution dropwise to a three-necked flask, stir and react at a water bath temperature of 0°C for 8h, place the solution in a refrigerator and let it stand overnight after the reaction, acidify 0.05g of carbon nanotubes with concentrated sulfuric acid and concentrated nitric acid at a mass ratio of carbon nanotubes:concentrated sulfuric acid:concentrated nitric acid = 1:100:33, and weigh 0.2g of sodium polyacrylate and add it to the above mixture and stir; obtain a uniform spinning solution;

[0036] Step 3, wet spinning: 10 mL of the spinning solution was filtered and defoamed, and finally wet-spinned to obtain a composite fiber; the specific parameters of the spinning were: the coagulation bath was methanol, the spinning solution was placed in a 10 mL propeller, and the propulsion speed was 0.8 mm / min; the fibers obtained by wet spinning were further woven into a fabric, and its electromagnetic shielding performance was measured to be 5 dB. Example

[0037] Step 1, collagen extraction: crush an appropriate amount of swollen sheepskin and add it to a 20% acetic acid solution, and stir rapidly in a water bath at 60°C for 12 hours to completely dissolve the acid skin;

[0038] Step 2, preparation of spinning solution: add 2g of aniline monomer and 20mL of hydrochloric acid (1M) to the collagen solution, stir rapidly at room temperature for 2h in a water bath, then dissolve ammonium persulfate (APS) initiator in an amount equal to that of aniline in 20mL of deionized water, slowly add the solution dropwise to a three-necked flask, stir and react in a 3°C water bath for 9h, place in a refrigerator and let stand overnight after the reaction, acidify 0.2g of carbon nanotubes with concentrated sulfuric acid and concentrated nitric acid in a mass ratio of carbon nanotubes:concentrated sulfuric acid:concentrated nitric acid = 1:100:33, and weigh 0.1g of sodium polyacrylate and add it to the above mixture and stir; obtain a uniform spinning solution;

[0039] Step 3, wet spinning: 10 mL of the spinning solution was filtered and defoamed, and finally wet-spinned to obtain a composite fiber; the specific spinning parameters were: the coagulation bath was methanol, the spinning solution was placed in a 10 mL propeller, and the propulsion speed was 0.8 mm / min; the fibers obtained by wet spinning were further woven into a fabric, and its electromagnetic shielding performance was measured to be 13 dB. Example

[0040] Step 1, collagen extraction: crush an appropriate amount of swollen sheepskin and add it to a 20% acetic acid solution, and stir rapidly in a water bath at 60°C for 12 hours to completely dissolve the acid skin;

[0041] Step 2, preparation of spinning solution: add 3g of aniline monomer and 30mL of hydrochloric acid (1M) to the collagen solution, and stir rapidly at room temperature for 3h in a water bath. Then, dissolve ammonium persulfate (APS) initiator in an amount equal to that of aniline in 30mL of deionized water, slowly add the solution dropwise to a three-necked flask, and stir the mixture in a 5°C water bath for 10h. After the reaction, place the mixture in a refrigerator and let it stand overnight. Acidify 0.2g of carbon nanotubes with concentrated sulfuric acid and concentrated nitric acid at a mass ratio of carbon nanotubes: concentrated sulfuric acid: concentrated nitric acid = 1:100:33, and weigh 0.3g of sodium polyacrylate and add it to the above mixture and stir to obtain a uniform spinning solution.

[0042] Step 3, wet spinning: 10 mL of the spinning solution was filtered and defoamed, and finally wet-spinned to obtain a composite fiber; the specific parameters of the spinning were: the coagulation bath was methanol, the spinning solution was placed in a 10 mL propeller, and the propulsion speed was 0.9 mm / min; the fibers obtained by wet spinning were further woven into a fabric, and its electromagnetic shielding performance was measured to be 12 dB.

[0043] See also Figure 1 When the carbon nanotube content is 0.05%, the SE value of the resulting fiber is low, remaining around 5dB at most frequencies, resulting in poor electromagnetic shielding effectiveness. Increasing the carbon nanotube content tightens the fiber's conductive network, improving its integrity and resulting in a significant increase in the SE value, with PMPC-20 reaching 13dB. When the fiber is coated with sodium polyacrylate, the structural integrity of the composite fiber is compromised, and its polarization ability is correspondingly reduced, thereby reducing both external reflection losses and internal absorption losses.

[0044] See also Figure 2 , showing the same electromagnetic wave loss mechanism of the obtained MWCNT / PANI / CA fiber. The MWCNT conductive network on the outside causes most electromagnetic waves to be reflected back into the environment when they come into contact with the surface of the material, and a small amount of electromagnetic waves enter the interior of the material and are reflected and absorbed secondary by the dense PANI layer.

[0045] See also Figure 3 During the spinning process, a petri dish containing a coagulation bath was used to weave and collect the spun fibers, forming a fabric of a certain thickness for analysis of the fiber morphology and properties. As shown in Figures 3 (a) and (b), due to the accumulation of fibers during weaving and the lack of timely transfer in the coagulation bath, the phase transition between the spun fibers and the coagulation bath, caused by double diffusion, reversed. Some fibers transitioned from the solid state back to the liquid state, and after freeze-drying the fabric, they adhered to fibers that had not undergone the phase transition, disrupting the fiber structure. Figure 3 (c) shows the fiber morphology at a higher magnification. The wet-spun fibers exhibit a more complete structure and more uniform diameter. Figure 3 (d) shows that the wet-spinning process can also cause fiber breakage due to the high viscosity of the spinning solution, which can clog the needle and cause the conductive filler to escape.

Claims

1. A method for preparing electromagnetic shielding fiber from sheepskin collagen by wet spinning, characterized in that: The following steps are involved: Step 1, collagen extraction: crush an appropriate amount of swollen sheepskin and add it to a 20% acetic acid solution. Stir rapidly in a water bath at 60°C for 12 hours to completely dissolve the sheepskin and obtain collagen. Step 2, preparation of spinning solution: 10 g of collagen obtained in step 1 was weighed and dissolved in 30 mL of deionized water, and ultrasonicated for 1-2 hours. Aniline monomer and hydrochloric acid were added thereto to carry out in-situ polymerization of aniline. The solution was then added to 0.05-0.2 g of the acidified carbon nanotube dispersion, followed by 0.1-0.3 g of sodium polyacrylate. The solution was stirred for 8-12 hours, filtered, and allowed to stand for defoaming to obtain a uniform spinning solution. The in-situ polymerization of aniline is specifically carried out as follows: Add 1-3 g of aniline monomer and 10-30 mL of hydrochloric acid to the collagen solution and stir rapidly in a water bath at room temperature for 1-3 hours. Then, dissolve ammonium persulfate in an amount equal to that of aniline in 10-30 mL of deionized water and slowly add it dropwise to the three-necked flask. Stir and react in a water bath at 0-5°C for 8-10 hours. After the reaction is complete, place the solution in a refrigerator and let it stand overnight. The acidified carbon nanotube dispersion is acidified using concentrated sulfuric acid and concentrated nitric acid, with a mass ratio of carbon nanotubes:concentrated sulfuric acid:concentrated nitric acid of 1:100:

33. Step 3, wet spinning: weigh 8-12 mL of the above spinning solution, filter and defoam the spinning solution, and wet spin it to obtain composite fibers, i.e., electromagnetic shielding fibers.

2. The method for preparing electromagnetic shielding fiber from sheepskin collagen by wet spinning according to claim 1, characterized in that: The wet spinning described in step 3 is specifically performed as follows: using methanol as a coagulation bath, placing the spinning solution in a 10 mL propeller, and pushing at a speed of 0.7 to 0.9 mm / min.

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