CN107326454B - A method for preparing auxetic nanofiber yarn by electrospinning - Google Patents

Abstract

The invention discloses a method for preparing auxetic nanofiber yarn by electrospinning, which is characterized in that a high-voltage electric field is used to spin a high-polymer solution or a high-polymer molten liquid through electrostatic force spinning to obtain a micro-nanofiber film and collect it in a On the auxetic structure collection device; the material selected on the rod of the auxetic texture on the auxetic structure collection device is different from that of the pores between the rods; The upper stripping and bundling; the post-treatment of the micro-nanofiber film to improve the friction performance between fibers, improve the mechanical properties of the auxetic nanofiber yarn or give it function. The present invention can be used for continuous and large-scale preparation of auxetic nanofiber yarns, and improves the production efficiency of auxetic nanofiber yarns; the prepared auxetic yarns have a stable structure and can be used in clothing, superhydrophobic materials, filter materials, biological Medical, tissue engineering, optoelectronic materials, impact protection, sensors, composite materials and other fields.

Description

A method for preparing auxetic nanofiber yarn by electrospinning

technical field

The invention relates to a method for preparing auxetic nanofiber yarns by electrospinning, in particular to a method for preparing auxetic nanofiber yarns by electrospinning, and belongs to the technical field of auxetic structural materials for textiles and clothing.

Background technique

Nanofibers not only have the characteristics of high specific surface area, but also have the advantages of good mechanical stability and good fiber continuity. Its applications have been involved in filtration, separation, sound absorption, energy, tissue engineering, biomedicine, sensors and other fields. However, from the perspective of application requirements in the fields of textile materials, composite materials, tissue engineering, and microelectronic devices, oriented nanofiber bundles and nanofiber yarns obtained after twisting are the ultimate development direction for nanofibers to be applied.

At present, there are many studies on the preparation of nanofiber yarns by electrospinning, such as CN200710044034.0 (a continuous preparation method for ultrafine electrospinning fiber yarns) awarded to Zhu Meifang et al., CN200810018267.8 (an electrostatic spinning nanofiber yarn system and preparation method of nanofiber yarn). In recent years, the research on the electrospun nanofiber yarn system mainly lies in the improvement of the clustering and twisting device, including the nozzle twisting method (He Jianxin; Cui Shizhong et al. A kind of air-jet spinning device and preparation method of electrospun nanofiber. Invention patent number CN201210207250.3), metal circular target method (Qin Xiaohong; Wu Shaohua. A continuous preparation device and method for oriented electrospinning nanofiber yarn. Invention patent number CN201310058070.8), jet friction method (He Jianxin; Zhou Yuman etc. A multi-strand air-jet friction yarn forming device and preparation method for electrospinning nanofibers. Invention patent number CN201510545647.7), ring collection method (Niu Haitao; Zhao Xiaoli. Rotary ring electrospinning nanofiber yarn preparation device and its Preparation method. Invention patent number CN201510149182.3), hollow rotating collection method (Niu Haitao; Zhao Xiaoli. Spinning collector to prepare electrospun nanofiber yarn device and its preparation method. Invention patent number CN201510148744.2), belt traction line and false twist Device method (Liu Chengkun; He Haijun, etc. An electrospinning nanofiber yarn device and a preparation method of nanofiber yarn. Invention patent number CN201610130682.7), rotating centrifugal column method (Wei Qufu; Lu Pengfei, etc. A one-step molding preparation High-speed centrifugal spinning device of nanofiber yarn and preparation method of nanofiber yarn. Invention patent number CN201610308336.3). Although the above method can prepare nanofiber yarn, its function is mainly provided by nanofibers. To make it have other properties, it can only be modified through post-treatment, which greatly increases the cost.

The property of negative Poisson's ratio is one of the unconventional characteristics of materials, which makes materials have special properties. Materials with negative Poisson's ratio properties are also called auxetic materials, and are known as one of the smart materials in the 21st century. The preparation of expanded yarn mainly adopts the traditional positive Poisson's ratio filament to form through the helical structure, so that when it is subjected to axial stretching, the filament components will change in structure due to different modulus, and the positions will be exchanged, which is manifested as yarn The apparent diameter of the thread increases, such as the Usesofauxetic fibers (US Patent, Invention Patent No. U.S.2011/8002879B2) granted to Hook, a negative Poisson's ratio yarn structure and its manufacturing method (Invention Patent No. CN201210212844.3). And its products can also be used in traditional textiles, such as a negative Poisson’s ratio woven fabric and its manufacturing method disclosed by Professor Hu Hong in 2016 (invention patent publication number CN106149150A), which is composed of the smallest repeating fabric structural unit, and the unit is composed of warp and weft yarns Common interweaving structure, the shape structure of the smallest repeating fabric structure unit is concave polygon, rotating polygon, star honeycomb structure, cross-linked polygon or concave folding structure, so that the woven fabric presents negative Poisson in one or more directions of its plane Ratio or zero Poisson's ratio effect, which can be used for wearing, such as the Articles ofapparel with auxetic fabrics granted to Blakely et al. respirator having an auxetic mesh in the mask body (US patent, invention patent number U.S.2015/8967147B2), can be used for impact protection, such as the Blast control blanket (US patent, invention patent number U.S.2016/0040962A1) granted to Rossow et al. Seating unit with auxetic support by Eberlein et al. (US Patent, Invention Patent No. U.S. 2015/0320220A1), etc. It can be seen that auxetic materials have broad prospects for use.

Contents of the invention

The problem to be solved by the present invention is to provide a method for preparing auxetic nanofiber yarns, and the prepared nanofiber yarns can be used as superhydrophobic materials.

In order to solve the above problems, the present invention provides a method for preparing auxetic nanofiber yarn by electrospinning, which is characterized in that it comprises the following steps:

Step 1): Using a high-voltage electric field to electrospin the polymer solution or polymer melt liquid to obtain a micro-nanofiber film and collect it on the auxetic structure collection device; the auxetic structure on the auxetic structure collection device Material A is selected on the rods of the auxetic lines in the pattern, and the pores between the rods of the auxetic lines are hollowed out or material B is selected, wherein material A and material B are materials with different electrical conductivity or materials with different magnetic permeability. The selection of the fiber aggregates deposited on the rods is hard, thick, and highly oriented, and the hollow structure or deposited fiber aggregates on the pores between the rods are soft, thin, low-oriented/disorderly arranged;

Step 2): peeling and bundling the collected micro-nanofibrous membrane with auxetic structure from the auxetic structure collection device;

Step 3): post-processing the micro-nanofiber membrane to improve the friction performance between fibers, improve the mechanical properties of the auxetic nanofiber yarn or endow it with functions.

Preferably, the electrospinning method in step 1) adopts single-needle, multi-needle or needle-free.

Preferably, the collection method of micro-nanofibers in step 1) adopts dry collection or wet collection.

More preferably, the wet collection is a bath collection method.

Preferably, in step 2), the micro-nanofibrous membrane is shaped by auxiliary equipment before bundling to stabilize the auxetic structure.

Preferably, the way of bundling in step 2) is ring bundling, hollow drum bundling, yarn guide rod bundling, metal circular target bundling or belt-drawn wire bundling.

Preferably, the micro-nanofibrous membrane with an auxetic structure in step 2) refers to a pattern or structure capable of forming an auxetic effect through deformation mechanisms such as stretching, bending, rotation, translation, and articulation, and is two-dimensional or three-dimensional Auxetic structure.

Preferably, the auxetic structure of the micro-nanofiber membrane is a concave honeycomb, a star network, a concave rhombus, a regular dodecahedron, a triangular lattice, a centrally rotated rectangle, a centrally rotated triangle, a centrally rotated tetrahedron, a chiral Any one or combination of honeycomb, central rotating polyhedron, articulated hexagon, articulated quadrilateral and articulated triangle.

Preferably, any one or more of mechanical twisting, false twisting, air twisting, eddy current twisting, air jet friction and chemical bonding is used in the post-treatment process in step 3).

The auxetic nanofiber yarn prepared by the invention has auxetic properties and also has the characteristics of nanofibers.

The principle of the present invention is that the high polymer solution or polymer molten liquid is drawn and spun to the auxetic structure collection device with an auxetic structure through a high voltage electric field; the auxetic structure pattern on the auxetic structure collection device, By selecting materials with different electrical conductivity or materials with different magnetic permeability on the rods with auxetic textures, and choosing materials with different electrical conductivity or different magnetic permeability in the pores between the auxetic textures and the rods with auxetic textures Materials with high conductivity, or ordinary materials, can realize the controllable deposition of polymer fibers, and realize that the fiber aggregates deposited on the rods are harder, thicker, and highly oriented, while the fiber aggregates deposited on the pores between the rods are relatively thick. Soft, thin, low orientation or random arrangement. The polymer fiber aggregate deposited on the auxetic structure collection device forms an auxetic structure before bundling. Through bundling and post-treatment, it not only increases its mechanical properties and endows it with functions, but also maintains the fibril aggregates before bundling. Auxetic structure, thus possessing auxetic effect. And because of the roughly disordered structure in the nanofiber deposition process and the fiber entanglement in the post-bundling process, the structure of the auxetic nanofiber yarn is stable, the deformation will not be too large, and it can be restored after the external force is removed.

Compared with prior art, the beneficial effect of the present invention is:

1. The method of the present invention adopts a one-time forming method, and the functional nanofiber yarn with auxetic performance can be produced without secondary processes such as post-treatment;

②The prepared auxetic nanofiber yarn shows auxetic effect under the action of auxetic structure, maintains the recovery ability after deformation under the interaction between fibers, and maintains the unique characteristics of nanomaterials in the presence of individual nanofibers, namely At the same time, there are stable auxetic properties and unique characteristics of nanomaterials;

③ The prepared auxetic nanofiber yarn has a stable structure and can be used in clothing, superhydrophobic materials, filter materials, biomedical, tissue engineering, optoelectronic materials, impact protection, sensors, composite materials and other fields. The market prospect is broad, especially for superhydrophobic materials. The field of hydrophobic materials;

④ The present invention can be used for continuous and large-scale preparation of auxetic nanofiber yarns.

Description of drawings

Fig. 1 is the schematic diagram of the chiral honeycomb two-dimensional auxetic micro-nanofibrous membrane prepared in Example 1;

Fig. 2 is the schematic diagram of the sinusoidal two-dimensional auxetic structure that embodiment 2 makes;

3 is a schematic diagram of the two-dimensional auxetic structure of the concave hexagonal honeycomb prepared in Example 3;

Fig. 4 is the schematic diagram of the double-arrow two-dimensional auxetic structure that embodiment 4 makes;

Fig. 5 is the schematic diagram of the star network two-dimensional auxetic structure that embodiment 5 makes;

6 is a schematic diagram of the three-dimensional auxetic structure of the concave honeycomb prepared in Example 6;

Fig. 7a is the schematic diagram of the three-dimensional auxetic structure of the double arrow made in embodiment 7;

Fig. 7b is a partially enlarged view of part I in Fig. 7a.

Detailed ways

In order to make the present invention more comprehensible, preferred embodiments are described in detail below with accompanying drawings.

Embodiments 1-7 all adopt a method for preparing auxetic nanofiber yarns by electrospinning provided by the present invention, the method comprising the following steps:

(a) preparation of the auxetic structure collection device;

(b) using a high-voltage electric field to spin the polymer solution or polymer molten liquid through electrostatic traction to spin the micro-nanofiber film and collect it on the auxetic structure collection device prepared in (a);

(c) peeling off and bundling the micro-nanofibrous membrane with auxetic structure collected in (b) from the auxetic structure collection device;

(d) The micro-nanofiber membranes are bundled and treated to improve the friction performance between fibers, improve the mechanical properties of the auxetic nanofiber yarns or endow them with functions.

The present invention can be used for the continuous and large-scale preparation of auxetic nanofiber yarns, improving the production efficiency of auxetic nanofiber yarns; the prepared auxetic yarns have a stable structure and can be used in clothing, superhydrophobic materials, filter materials, biological Medical, tissue engineering, optoelectronic materials, impact protection, sensors, composite materials and other fields, especially in the field of superhydrophobic materials.

Example 1

Polyamide 6 is used as the raw material, the rods of the auxetic structure pattern on the auxetic structure collection device are made of gold wires, the pores between the rods are copper wires, multi-needle electrospinning, the deposited fibers are collected by wet method, and the auxetic structure pattern is made of chiral honeycomb structure, and then add an auxiliary drying mechanism to dry, use a metal circular target to cluster and deposit nanofiber webs (as shown in Figure 1), and finally use air twisting to form auxetic nanofiber yarns.

Example 2

Polyurethane is used as the raw material, copper wire is used for the auxetic structure pattern rod on the auxetic structure collection device, and the holes between the rods are aluminum wire, multi-needle electrospinning, the deposited fiber is collected by dry method, and the auxetic structure pattern is sinusoidal In the two-dimensional auxetic structure, a metal circular target is used to cluster and deposit nanofiber webs (as shown in Figure 2), and finally air twisting is used to form auxetic nanofiber yarns.

Example 3

The raw material is polyester, and the auxetic structure pattern rod on the auxetic structure collection device is made of copper wire. The pores between the rods are made of stainless steel. Single-needle electrospinning is used to collect deposited fibers by dry method. The auxetic structure pattern is selected from concave hexagonal honeycomb. The deposited nanofiber web (as shown in Figure 3) is bundled in a ring, and finally mechanically twisted into an auxetic nanofiber yarn.

Example 4

Polyacrylonitrile is used as raw material, the auxetic structure pattern rod on the auxetic structure collection device is made of silver wire, the pores between the rods are made of stainless steel, there is no needle electrospinning, the deposited fiber is collected by dry method, and the auxetic structure pattern is selected from double arrow auxetic structure, using a metal circular target to bundle and deposit nanofiber webs (as shown in Figure 4), and finally use friction twisting to form auxetic nanofiber yarns.

Example 5

Polypropylene is used as the raw material, the rods of the auxetic structure pattern on the auxetic structure collection device are made of stainless steel wire, and the pores between the rods are made of polytetrafluoroethylene film. Type network structure, using the nanofiber network deposited by the ring bundle (as shown in Figure 5), and finally using false twist to form the auxetic nanofiber yarn.

Example 6

Polyvinyl alcohol is used as the raw material, the rods of the auxetic structure pattern on the auxetic structure collection device are made of copper wire, the holes between the rods are hollowed out, needle-free electrospinning, the deposited fibers are collected by dry method, and the auxetic structure pattern is selected from concave hexagonal honeycomb ( As shown in Figure 6), the deposited nanofiber web is bundled with a ring, and finally mechanically twisted into an auxetic nanofiber yarn.

Example 7

Using polylactic acid as raw material, the rods of the auxetic structure pattern on the auxetic structure collection device are made of silver wire, and the pores between the rods are made of aluminum wire. There is no needle-head electrospinning, and the deposited fibers are collected by dry method. The auxetic structure pattern is made of double arrow three-dimensional drawing In order to expand the structure, a metal circular target is used to bundle and deposit nanofiber webs (as shown in Figures 7a and 7b), and finally air twisting is used to form auxetic nanofiber yarns.

Claims (9)

1. a method for preparing auxetic nanofiber yarn by electrospinning, is characterized in that, comprises the following steps: Step 1): Using a high-voltage electric field to electrospin the polymer solution or polymer melt liquid to obtain a micro-nanofiber film and collect it on the auxetic structure collection device; the auxetic structure on the auxetic structure collection device Material A is selected on the rods of the auxetic lines in the pattern, and the pores between the rods of the auxetic lines are hollowed out or material B is selected, wherein material A and material B are materials with different electrical conductivity or materials with different magnetic permeability. The selection of the fiber aggregates deposited on the rods is hard, thick, and highly oriented, and the hollow structure or deposited fiber aggregates on the pores between the rods are soft, thin, low-oriented/disorderly arranged; Step 2): peeling and bundling the collected micro-nanofibrous membrane with auxetic structure from the auxetic structure collection device; Step 3): post-processing the micro-nanofiber membrane to improve the friction performance between fibers, improve the mechanical properties of the auxetic nanofiber yarn or endow it with functions. 2. The method for preparing auxetic nanofiber yarns by electrospinning according to claim 1, characterized in that, the electrospinning method in the step 1) adopts single-needle type, multi-needle type or needle-free type. 3. The method for preparing auxetic nanofiber yarns by electrospinning as claimed in claim 1, characterized in that, the collection method of micro-nanofibers in the step 1) adopts dry collection or wet collection. 4. The method for preparing auxetic nanofiber yarns by electrospinning according to claim 3, wherein the wet collection is a bath collection method. 5. electrospinning as claimed in claim 1 prepares the method for auxetic nanofiber yarn, it is characterized in that, described step 2) in micro-nanofiber film it is shaped to stabilize auxetic by auxiliary equipment before bundling structure. 6. electrospinning as claimed in claim 1 prepares the method for auxetic nanofiber yarn, it is characterized in that, described step 2) the mode of bundling is ring bundling, hollow rotary drum bundling, guide rod bundling, Metal circular target bundle or bundle with drawing wire. 7. The method for preparing auxetic nanofiber yarns by electrospinning according to claim 1, characterized in that, the micro-nanofiber membrane having an auxetic structure in the step 2) is a two-dimensional or three-dimensional auxetic structure. 8. The method for preparing the auxetic nanofiber yarn by electrospinning as claimed in claim 7, is characterized in that, the auxetic structure of the micro-nanofiber film is concave honeycomb, star network, concave rhombus, positive Any one or a combination of dodecahedron, triangular lattice, centrally rotated rectangle, centrally rotated triangle, chiral honeycomb, centrally rotated polyhedron, articulated hexagon, articulated quadrilateral, and articulated triangle. 9. electrospinning as claimed in claim 1 prepares the method for auxetic nanofiber yarn, it is characterized in that, described step 3) post-processing procedure adopts mechanical twisting, false twisting, air twisting, eddy current twisting , any one or more of the processes of jet friction and chemical bonding.