阅读说明：本技术 一种MXene/海藻酸钠复合无纺织物的制备方法 (Preparation method of MXene/sodium alginate composite non-woven fabric ) 是由 隋超 赵国欣 王超 赫晓东 赵予顺 李钧姣 苗琳琳 于 2021-10-29 设计创作，主要内容包括：一种MXene/海藻酸钠复合无纺织物的制备方法。本发明为了解决MXene织物制备过程中存在加工成型困难、纤维非连续以及生产效率低等问题,制备过程如下：通过磁力搅拌得到MXene/SA复合溶液,将MXene/SA复合溶液注入至甩丝设备进行甩丝,利用凝固浴固化纤维并在圆柱形收集装置上进行纤维的收集,通过简单的冲压手段得到MXene/SA复合无纺织物。单丝沿着纤维轴向定向排列,可极大程度上提升织物的力学性能。复合纤维表面具有明显的沟槽以及褶皱结构,以及单丝堆叠产生的多孔性,这种多级形貌特征非常有利于电磁波的吸收,电磁屏蔽效能达到35dB左右。本发明制备的MXene/SA织物具有优异的电磁屏蔽性能以及力学性能,同时其制备方法具有简单、高效以及成本低廉等特征。(A method for preparing MXene/sodium alginate composite non-woven fabric. In order to solve the problems of difficult processing and forming, discontinuous fiber, low production efficiency and the like in the preparation process of the MXene fabric, the preparation process comprises the following steps: the MXene/SA composite solution is obtained through magnetic stirring, the MXene/SA composite solution is injected into a spinning device for spinning, fiber is solidified by utilizing a coagulating bath and collected on a cylindrical collecting device, and the MXene/SA composite non-woven fabric is obtained through a simple stamping method. The monofilaments are arranged along the axial direction of the fiber, so that the mechanical property of the fabric can be greatly improved. The surface of the composite fiber has obvious grooves and fold structures and porosity generated by monofilament stacking, the multilevel morphological characteristics are very favorable for absorption of electromagnetic waves, and the electromagnetic shielding efficiency reaches about 35 dB. The MXene/SA fabric prepared by the method has excellent electromagnetic shielding performance and mechanical property, and the preparation method has the characteristics of simplicity, high efficiency, low cost and the like.)

1. A preparation method of MXene/sodium alginate composite non-woven fabric is characterized by comprising the following steps: the method comprises the following steps:

step one, preparing MXene/SA composite solution: obtaining a colloidal solution consisting of MXene lamella by combining in-situ hydrofluoric acid etching with ultrasonic stripping, adding sodium alginate powder into the MXene colloidal solution, and magnetically stirring for 1-24h at 25-80 ℃ to obtain an MXene/SA composite solution;

step two, preparation of a coagulating bath: anhydrous CaCl is added₂Adding into deionized water, magnetically stirring to dissolve CaCl₂The concentration of the solution is 5 wt% -10 wt%, and then the well dissolved CaCl is added₂Adding isopropanol and CaCl into the solution₂The volume ratio of the solution to the isopropanol is 0.1-6: 1, magnetically stirring until no obvious layering exists in the solution, and obtaining a coagulating bath;

step three, preparing the MXene/SA composite non-woven fabric: injecting the MXene/SA composite solution into a spinning device for spinning, collecting fibers by using a cylindrical collecting device with a rotor in a coagulating bath, stamping the cleaned continuous fiber bundle in a direction perpendicular to the orientation direction, finally placing the stamped sample in liquid nitrogen, and transferring the sample to a freeze dryer for drying.

2. The method for preparing MXene/sodium alginate composite non-woven fabric according to claim 1, wherein the method comprises the following steps: in the first step, MXene is Ti₃C₂T_X。

3. The method for preparing MXene/sodium alginate composite non-woven fabric according to claim 1, wherein the method comprises the following steps: in the first step, the mass ratio of MXene to SA is 0.1-10: 1.

4. the method for preparing MXene/sodium alginate composite non-woven fabric according to claim 1, wherein the method comprises the following steps: in the first step, the preparation process is carried out in an oil bath, the temperature of the oil bath is 25-60 ℃, and the magnetic stirring time is 6-24 h.

5. The method for preparing MXene/sodium alginate composite non-woven fabric according to claim 1, wherein the MXene/sodium alginate composite non-woven fabric is prepared by the method comprisingThe method comprises the following steps: in the second step, the CaCl₂The concentration of the solution was 5 wt%.

6. The method for preparing MXene/sodium alginate composite non-woven fabric according to claim 1, wherein the method comprises the following steps: in the second step, the CaCl₂The volume ratio of the solution to the isopropanol is 4: 1.

7. the method for preparing MXene/sodium alginate composite non-woven fabric according to claim 1, wherein the method comprises the following steps: in the third step, the pressure of the stamping is 0.02MPa-10MPa, and the time is 20s-300 s.

8. The method for preparing MXene/sodium alginate composite non-woven fabric according to claim 7, wherein the method comprises the following steps: in the third step, the pressure of the stamping is 0.2MPa, and the time is 200 s.

9. The method for preparing MXene/sodium alginate composite non-woven fabric according to claim 1, wherein the method comprises the following steps: in the third step, the drying pressure is 2-100Pa, and the temperature is-60 to-100 ℃.

10. The method for preparing MXene/sodium alginate composite non-woven fabric according to claim 9, wherein: in the third step, the drying pressure is 20Pa, and the temperature is-80 ℃.

Technical Field

The invention belongs to the technical field of non-woven fabric preparation, and particularly relates to a preparation method of an MXene/sodium alginate composite non-woven fabric.

Background

MXene is a new type of two-dimensional transition metal carbide or/and nitride which develops very rapidly in recent years and has a structural general formula of M_n+1X_nT_xWherein M is an early transition metal, X is carbon and/or nitrogen, T_xRepresenting the end groups. MXene has all the basic properties required for a highly efficient EMI shielding material, i.e., good electrical conductivity, large specific surface area, light weight, etc. In addition to this, the most important is its easy-to-process nature. Their adjustable surface chemical properties promote the development of MXene and composite materials with controllable structural design, such as fiber, film or block structures, and have wide application prospects in high and new technical fields of aerospace, national defense and the like.

Since MXene shows excellent dispersibility in various solvents, functional fibers and smart textiles of MXene can be prepared by different spinning techniques. However, MXene has limited its further development and practical application due to problems such as its small transverse dimension and poor mechanical properties between the plies and after textile formation. Fortunately, the easy solution processing characteristic of MXene makes the MXene and other materials easy to assemble into composite materials, and then the excellent performances of the MXene and the other materials are effectively combined to prepare MXene-based composite textiles with excellent conductivity and mechanical performance, so that the development requirement of the integration of advanced material structure and function is met.

It is worth noting that the preparation of Mxene fabrics is still in the beginning stage at present, and the main preparation methods include traditional coating, electrostatic spinning and wet spinning, the coating method faces the disadvantages of insufficient uniformity, weak interface bonding force, and the need of surface modification to the textile substrate, etc., high pressure condition is usually required in electrostatic spinning, toxic solvent is used, Mxene loading is low, fiber production efficiency is low in wet spinning, and post-treatment of weaving is usually required. Due to the limitation of the preparation process, the MXene-based composite textile still has the problems of weak interface bonding force between MXene and the textile, non-continuity of fibers, low MXene loading capacity, low production efficiency, requirement of post-treatment after weaving and the like.

Disclosure of Invention

The invention aims to solve the problems of difficult processing and forming, low MXene loading capacity, discontinuous fiber, low production efficiency and the like in the MXene fabric preparation process, and provides a preparation method of an MXene/sodium alginate composite non-woven fabric.

The MXene/SA composite non-woven fabric is obtained by throwing spinning solution with certain viscosity out through a spinning nozzle rotating at a high speed, enabling the jet flow of the composite solution to contact with a coagulating bath to coagulate and solidify fibers, and further performing stamping and freeze drying post-treatment.

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

a preparation method of MXene/sodium alginate composite non-woven fabric is carried out according to the following steps:

step one, preparing MXene/SA composite solution: obtaining a colloidal solution consisting of MXene lamella by combining in-situ hydrofluoric acid etching with ultrasonic stripping, adding sodium alginate powder (SA) into the MXene colloidal solution, and magnetically stirring for 1-24h at 25-80 ℃ to obtain MXene/SA composite solution;

step two, preparation of a coagulating bath: anhydrous CaCl is added₂Adding into deionized water, magnetically stirring to dissolve CaCl₂The concentration of the solution is 5 wt% -10 wt%, and then the well dissolved CaCl is added₂Adding isopropanol and CaCl into the solution₂The volume ratio of the solution to the isopropanol is 0.1-6: 1, magnetically stirring until no obvious layering of the solution occurs to obtainTo a coagulation bath;

step three, preparing the MXene/SA composite non-woven fabric: injecting the MXene/SA composite solution into a spinning device for spinning, collecting fibers by using a cylindrical collecting device with a rotor in a coagulating bath, stamping the cleaned continuous fiber bundle in a direction perpendicular to the orientation direction, finally placing the stamped sample in liquid nitrogen, and transferring the sample to a freeze dryer for drying.

Further, in consideration of the conductivity of the composite nonwoven fabric and the ease of preparation of raw materials, MXene is Ti in the first step₃C₂T_X。

Further, in the first step, the mass ratio of MXene to SA is 0.1-10: 1.

further, in the first step, the preparation process is carried out in an oil bath, the temperature of the oil bath is 25-60 ℃, and the magnetic stirring time is 6-24 h.

Further, in step two, the CaCl is added in consideration of the appropriate degree of solidification of the composite fiber₂The concentration of the solution was 5 wt%.

Further, in view of increasing the curing speed of the fiber, in the second step, the CaCl is added₂The volume ratio of the solution to the isopropanol is 4: 1.

further, in the third step, the pressure of the stamping is 0.02MPa-10MPa, and the time is 20s-300 s.

Further, in consideration of the compactness and the pressure resistance of the composite non-woven fabric, in the third step, the pressing pressure is 0.2MPa, and the time is 200 s.

Further, in the third step, the drying pressure is 2-100Pa, and the temperature is-60 to-100 ℃.

Further, in the third step, the drying pressure was 20Pa and the temperature was-80 ℃ in consideration of the final forming speed of the composite nonwoven fabric.

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

1. the preparation method can finish the preparation of the composite non-woven fabric with high MXene content by adopting high-speed centrifugal equipment and a simple stamping method matched with a coagulating bath, and the composite fabric has the structural characteristics of continuity, porosity and directional arrangement. The invention controls the electromagnetic shielding performance of the composite non-woven fabric by simply regulating and controlling the viscosity of the spinning solution, the proportion of the coagulating bath and the processing parameters after stamping, and the composite fabric has wide application prospect in the fields of sensors, energy storage and the like due to the excellent conductivity and the advanced structure of the fabric. Meanwhile, the sodium alginate and other raw materials are cheap, so that the preparation method has the characteristic of low cost.

2. The invention provides a method for preparing a non-woven fabric composed of high-content MXene continuous fibers by using a novel immersion spinning process and a simple stamping post-treatment mode, without using high pressure and toxic solvent or knitting post-treatment.

3. At present, MXene fabrics are applied to relevant work in the electromagnetic shielding direction, the production methods are almost all coating methods, and the MXene/SA composite non-woven fabric prepared by the method has excellent electromagnetic shielding performance and integrates the advantages of the preparation process, so that the method disclosed by the invention belongs to the leading level.

Drawings

FIG. 1 is a scanned image of the surface topography of a composite nonwoven fabric prepared in example 3;

fig. 2 is a graph showing electromagnetic shielding properties of the composite nonwoven fabric prepared in example 3.

Detailed Description

The technical solution of the present invention is further described below with reference to the drawings and the embodiments, but the present invention is not limited thereto, and modifications or equivalent substitutions may be made to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention.

Example 1:

the method for preparing MXene/SA composite non-woven fabric by an immersion spinning method comprises the following steps:

step one, preparing MXene/SA composite solution: adding 2g of sodium alginate into 100ml of MXene solution with the concentration of 20mg/ml, and stirring for 18h at 50 ℃ to obtain MXene/SA composite solution;

step two, preparation of a coagulating bath: 1800ml of CaCl with the mass fraction of 5 percent₂Adding the solution into 300ml of isopropanol, and stirring until no obvious layering exists;

step three, preparing the MXene/SA composite non-woven fabric: and injecting the MXene/SA composite solution into spinning equipment for spinning, collecting fibers by using a cylindrical collecting device with a rotor in a coagulating bath, and stamping the cleaned continuous fiber bundle in a direction perpendicular to the orientation direction, wherein the stamping pressure is 5MPa and the stamping time is 300 s. And finally, placing the punched sample in liquid nitrogen, transferring the sample to a freeze dryer for drying, wherein the vacuum degree is 20Pa, and the temperature is-80 ℃.

The electromagnetic shielding effectiveness of the MXene/SA composite non-woven fabric obtained in the embodiment is about 28dB, and the value is superior to the electromagnetic shielding performance of the MXene composite material reported by most of the current work.

Example 2:

the method for preparing MXene/SA composite non-woven fabric by an immersion spinning method comprises the following steps:

step one, preparing MXene/SA composite solution: adding 1g of sodium alginate into 250ml of MXene solution with the concentration of 20mg/ml, and stirring for 24h at 25 ℃ to obtain MXene/SA composite solution;

step two, preparation of a coagulating bath: 1200ml of CaCl with the mass fraction of 5 percent₂Adding the solution into 1800ml of isopropanol, and stirring until no obvious layering exists;

step three, preparing the MXene/SA composite non-woven fabric: and injecting the MXene/SA composite solution into spinning equipment for spinning, collecting fibers by using a cylindrical collecting device with a rotor in a coagulating bath, and stamping the cleaned continuous fiber bundle in a direction perpendicular to the orientation direction, wherein the stamping pressure is 0.02MPa and the stamping time is 30 s. And finally, placing the punched sample in liquid nitrogen, transferring the sample to a freeze dryer for drying, wherein the vacuum degree is 20Pa, and the temperature is-80 ℃.

The electromagnetic shielding effectiveness of the MXene/SA composite non-woven fabric obtained in the embodiment is about 45dB, and the value is superior to the electromagnetic shielding performance of the MXene composite material reported by most of the current work.

Example 3:

the method for preparing MXene/SA composite non-woven fabric by an immersion spinning method comprises the following steps:

step one, preparing MXene/SA composite solution: adding 1g of sodium alginate into 150ml of MXene solution with the concentration of 20mg/ml, and stirring for 18h at 35 ℃ to obtain MXene/SA composite solution with moderate viscosity;

step two, preparation of a coagulating bath: 2400ml of CaCl with the mass fraction of 5 percent₂Adding the solution into 600ml of isopropanol, and stirring until no obvious layering exists;

step three, preparing the MXene/SA composite non-woven fabric: and injecting the MXene/SA composite solution into spinning equipment for spinning, collecting fibers by using a cylindrical collecting device with a rotor in a coagulating bath, and stamping the cleaned continuous fiber bundle in a direction perpendicular to the orientation direction, wherein the stamping pressure is 0.2MPa and the stamping time is 200 s. And finally, placing the punched sample in liquid nitrogen, transferring the sample to a freeze dryer for drying, wherein the vacuum degree is 20Pa, and the temperature is-80 ℃.

The electromagnetic shielding effectiveness of the MXene/SA composite non-woven fabric obtained in the embodiment is about 35dB, and as shown in figure 2, the value is superior to the electromagnetic shielding performance of the MXene composite material reported by most of the current work. And as can be seen from the surface topography scanning image of the composite fabric shown in the attached figure 1, the monofilaments are directionally arranged along the axial direction of the fibers and the continuity of the monofilaments can greatly improve the mechanical property of the fabric. Meanwhile, the surface of the composite fiber has obvious grooves and fold structures and porosity generated by fiber stacking, and the multilevel morphological characteristics are very favorable for absorption of electromagnetic waves. The MXene/SA fabric prepared by the method has excellent electromagnetic shielding performance and mechanical property, meets the development requirement of advanced material structure-function integration, and has the characteristics of simplicity, high efficiency, low cost and the like.