Aramid fiber micro-nano fiber with dendritic structure prepared by double-jet method and application thereof
阅读说明：本技术 一种利用双射流法制备具有树枝状结构的芳纶微纳米纤维及其应用 (Aramid fiber micro-nano fiber with dendritic structure prepared by double-jet method and application thereof ) 是由 李金鹏 李永锋 王斌 常小斌 曾劲松 陈克复 于 2021-09-07 设计创作，主要内容包括：本发明公开了一种利用双射流法制备具有树枝状结构的芳纶微纳米纤维及其应用。该芳纶微纳米纤维的制备方法包括如下步骤：(1)将芳纶聚合物加入到分散溶剂中,得到芳纶聚合物分散液；(2)将芳纶聚合物分散液进行气喷雾化处理,同时将分散剂进行气喷雾化处理,然后将气喷雾化处理形成的两股射流充分混合后收集,再分散于水中进行超声分散处理,得到具有树枝状结构的芳纶微纳米纤维；其中,气喷雾化处理的条件为：喷丝孔型为内进气孔,外进液孔,雾化器的孔径范围为0.1～5.0mm,气体压力范围为0.1～1.0MPa。本发明所制备的微纳米纤维比表面积大,可显著改善芳纶纸内纤维界面结合强度,有效提升芳纶纸机械强度和介电性能。(The invention discloses an aramid fiber micro-nanofiber with a dendritic structure prepared by a double-jet method and application thereof. The preparation method of the aramid micro-nano fiber comprises the following steps: (1) adding an aramid polymer into a dispersion solvent to obtain an aramid polymer dispersion liquid; (2) carrying out air-jet atomization treatment on the aramid polymer dispersion liquid, simultaneously carrying out air-jet atomization treatment on the dispersing agent, fully mixing two jets formed by the air-jet atomization treatment, collecting the mixture, and dispersing the mixture in water for ultrasonic dispersion treatment to obtain the aramid micro-nanofiber with the dendritic structure; wherein, the conditions of the gas spray atomization treatment are as follows: the spinneret orifices are inner air inlet holes and outer liquid inlet holes, the aperture range of the atomizer is 0.1-5.0 mm, and the gas pressure range is 0.1-1.0 MPa. The micro-nanofiber prepared by the method has a large specific surface area, can obviously improve the bonding strength of the fiber interface in the aramid paper, and effectively improves the mechanical strength and the dielectric property of the aramid paper.)
1. A method for preparing aramid fiber micro-nanofibers with dendritic structures by using a double-jet method is characterized by comprising the following steps:
(1) preparing an aramid polymer dispersion liquid: adding an aramid polymer into a dispersion solvent, and uniformly stirring and dispersing to obtain an aramid polymer dispersion liquid;
(2) preparing aramid micro-nano fibers: carrying out air-jet atomization treatment on the aramid polymer dispersion liquid obtained in the step (1), simultaneously carrying out air-jet atomization treatment on a dispersing agent, fully mixing two jet flows formed by the air-jet atomization treatment, collecting, and dispersing in water for ultrasonic dispersion treatment to obtain the aramid micro-nanofiber with the dendritic structure; wherein, the conditions of the gas spray atomization treatment are as follows: the spinneret orifices of the atomizer are an inner air inlet and an outer liquid inlet, the aperture range is 0.1-5.0 mm, and the gas pressure range is 0.1-1.0 MPa.
2. The method for preparing the aramid micro-nanofibers with the dendritic structure by using the dual-jet method as claimed in claim 1, wherein:
the aramid polymer in the step (1) is at least one of poly (m-phenylene isophthalamide), poly (p-phenylene terephthalamide) and polyamide polymer containing a heterocyclic ring structure;
the dispersing solvent in the step (1) is one or a mixture of N, N-dimethylacetamide, N-dimethylformamide, dimethyl sulfoxide and acetone;
the concentration of the aramid polymer dispersion liquid in the step (1) is 1-20% by mass;
the dispersant in the step (2) is one or a mixture of N, N-dimethylacetamide, N-dimethylformamide, dimethyl sulfoxide, acetone and water;
and (3) collecting in the step (2) at a distance of 10-100 cm from a nozzle of the atomizer.
3. The method for preparing the aramid micro-nanofibers with the dendritic structure by using the dual-jet method as claimed in claim 2, wherein:
the aramid polymer in the step (1) is poly (m-phenylene isophthalamide);
the dispersing solvent in the step (1) is N, N-dimethylacetamide;
the concentration of the aramid polymer dispersion liquid in the step (1) is 12-20% by mass;
the dispersing agent in the step (2) is water or an N, N-dimethylacetamide solution with the concentration of 10-70% by mass;
and (3) collecting in the step (2) at a distance of 20-40 cm from a nozzle of the atomizer.
4. The method for preparing the aramid micro-nanofibers with the dendritic structure by using the dual-jet method as claimed in claim 1, wherein:
the stirring conditions in the step (1) are as follows: the rotating speed is 50-10000 rpm, and the stirring time is 1-60 min;
the conditions for carrying out air-jet atomization treatment on the aramid polymer dispersion liquid in the step (2) are as follows: the aperture range of the atomizer is 1.0-3.0 mm; the gas pressure is 0.2-1.0 MPa;
the conditions for carrying out the air-jet atomization treatment on the dispersing agent in the step (2) are as follows: the aperture range of the atomizer is 1.0-3.0 mm, and the gas pressure range is 0.5-0.8 MPa;
the gas source for the gas-jet atomization treatment in the step (2) is at least one of air, nitrogen and argon;
the ultrasonic treatment conditions in the step (2) are as follows: the power is 200-3000W, and the time is 1-200 min.
5. The utility model provides a micro-nanofiber of aramid fiber with dendritic structure which characterized in that: prepared by the method of any one of claims 1 to 4.
6. The application of the aramid micro-nano fiber with the dendritic structure in preparing aramid paper.
7. An aramid paper, its characterized in that: the aramid micro-nano fiber with the dendritic structure is manufactured by paper making of the aramid micro-nano fiber with the dendritic structure.
8. The aramid micro-nanofiber with a dendritic structure as claimed in claim 5 and/or the aramid paper as claimed in claim 7, for use in composite reinforcement materials, battery separator materials, adsorption filtration materials, electrical insulation materials or flexible electronic devices.
9. An atomizer for preparing the aramid micro-nanofibers with dendritic structures of claim 5, characterized in that: comprises a polymer atomizing device, a curing agent atomizing device and a receiving tray (8);
the polymer atomization device comprises a polymer negative pressure generation device and a feeding pipe (5-1) used for conveying a polymer, wherein the feeding pipe (5-1) is arranged on one side of the polymer negative pressure generation device, the feeding pipe (5-1) is provided with a polymer discharge port, the polymer negative pressure generation device is provided with a nozzle (9-1), the polymer discharge port is arranged on one side of the nozzle (9-1), and the polymer discharge port and the nozzle (9-1) are arranged in the same direction;
the solidified reagent atomization device comprises a solidified reagent negative pressure generation device and a feeding pipe (5-2) used for conveying a solidified reagent, wherein the feeding pipe (5-2) is arranged on one side of the solidified reagent negative pressure generation device, the feeding pipe (5-2) is provided with a solidified reagent discharge port, the solidified reagent negative pressure generation device is provided with a nozzle (9-2), the solidified reagent discharge port is arranged on one side of the nozzle (9-2), and the solidified reagent discharge port and the nozzle (9-2) are arranged in the same direction;
a receiving tray (8) is arranged below the nozzle (9-1) and the nozzle (9-2).
10. The nebulizer of claim 9, wherein:
a nozzle (9-1) of the polymer negative pressure generating device is arranged in the feeding pipe (5-1) in a penetrating way, and the cross section of a polymer discharging port is larger than that of the nozzle (9-1);
the feeding pipe (5-1) comprises a first pipe body and a second pipe body, the first pipe body and the second pipe body are communicated with each other, an included angle between the first pipe body and the second pipe body is less than 180 degrees, the polymer discharging port is arranged on the second pipe body, and a nozzle (9-1) of the polymer negative pressure generating device penetrates through the second pipe body;
the polymer negative pressure generating device comprises an air compressor (1), an air pipe (3-1) and a pressure regulating valve (2-1), one end of the air pipe (3-1) is connected to the air compressor (1), a nozzle (9-1) is arranged at the other end of the air pipe (3-1), the pressure regulating valve (2-1) is connected to the air pipe (3-1), the air pipe (3-1) penetrates through the second pipe body, and the air pipe (3-1) is parallel to the second pipe body;
a nozzle (9-2) of the solidified reagent negative pressure generating device is arranged in the feeding pipe (5-2) in a penetrating way, and the cross section of the solidified reagent discharging port is larger than that of the nozzle (9-2);
the feeding pipe (5-1) comprises a third pipe body and a fourth pipe body, the third pipe body and the fourth pipe body are communicated with each other, an included angle between the third pipe body and the fourth pipe body is smaller than 180 degrees, a curing reagent discharging port is formed in the fourth pipe body, and a nozzle (9-2) of the curing reagent negative pressure generating device penetrates through the fourth pipe body;
the negative pressure generation device for the curing reagent comprises an air compressor (1), an air pipe (3-2) and a pressure regulating valve (2-2), one end of the air pipe (3-2) is connected to the air compressor (1), a nozzle (9-2) is arranged at the other end of the air pipe (3-2), the pressure regulating valve (2-2) is connected to the air pipe (3-2), the air pipe (3-2) penetrates through a fourth pipe body, and the air pipe (3-2) is parallel to the fourth pipe body.
Technical Field
The invention belongs to the field of new materials, and particularly relates to an aramid fiber micro-nanofiber with a dendritic structure prepared by a double-jet method and application thereof.
Background
The aramid fiber micro-nano fiber has the advantages of micro-nano aramid fiber, high length-diameter ratio, high specific surface area, excellent strength modulus, outstanding chemical and thermal stability and the like, and is widely applied to various fields. Since 2011, it was considered one of the most promising nano-building materials and has therefore received increasing attention. At present, the technology for preparing the aramid nano-fiber is relatively short, and the technology for industrial production is more scarce. At present, the methods for preparing aramid fiber micro-nanofibers are mostly a deprotonation method, an alkaline method and a mechanical method according to a dissolving method, and also include an electrostatic spinning method, a proton exchange method and a jet method, and the obtained aramid fiber micro-nanofibers are cylindrical or linear, are single in shape and structure, are difficult to regulate and control in size, and are low in production efficiency.
For example, chinese patent application No. 202011304031.8 entitled "a method for preparing an aramid nanofiber dispersion" and chinese patent No. 201810141423.3 entitled "a method for preparing an aramid nanofiber by a mechanically coupled chemical alkali dissolution method" and chinese patent No. 201910340388.2 entitled "a method for preparing an aramid nanofiber" disclose a method for preparing an aramid nanofiber by KOH/DMSO or DMSO, and the process is complicated by obtaining an aramid nanofiber dispersion through mechanical coupled chemical alkali dissolution treatment, combined with a deprotonation process, and multiple replacement washing.
The conventional jet spinning technology mostly adopts an inner liquid inlet pipe and an outer gas inlet pipe, and the prepared aramid fiber has large diameter, uncontrollable length and wide size distribution range; the electrostatic spinning technology has low production efficiency and great regulation difficulty, and the technical defects limit the industrialization process and the application range of the aramid micro-nano fiber.
In summary, the currently reported methods for preparing the aramid micro-nanofibers include electrostatic spinning, rotary jet spinning, alkali-assisted mechanical milling and hydrolysis, an alkali dissolution method, a polymerization dispersion method, and the like. The electrostatic spinning method has low production efficiency and difficult size regulation; the alkali fusion method needs to dissolve aramid fiber and then redisperse, and the process is complicated; the mechanical method has high energy consumption and large power consumption; the existing jet spinning technology adopts an inner liquid inlet pipe and an outer air inlet pipe, and the prepared aramid fiber has the advantages of large diameter, uncontrollable length and wide size distribution range. Therefore, the search for a rapid and effective aramid fiber micro-nanofiber preparation technology has important significance for realizing functionalization and high performance of the aramid fiber micro-nanofiber and cross diversified application of the aramid fiber micro-nanofiber in various fields such as reinforced materials, battery diaphragms, electric insulation nano-paper, flexible electronic devices, adsorption filter media and the like.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides a method for preparing aramid micro-nanofibers with dendritic structures by using a double-jet method.
The invention also aims to provide the aramid micro-nano fiber with the dendritic structure prepared by the method.
The invention further aims to provide application of the aramid fiber micro-nanofiber with the dendritic structure.
The purpose of the invention is realized by the following technical scheme:
a method for preparing aramid fiber micro-nanofibers with dendritic structures by using a double-jet method comprises the following steps:
(1) preparing an aramid polymer dispersion liquid: adding an aramid polymer into a dispersion solvent, and uniformly stirring and dispersing to obtain an aramid polymer dispersion liquid;
(2) preparing aramid micro-nano fibers: carrying out gas atomization treatment on the aramid polymer dispersion liquid obtained in the step (1), simultaneously carrying out gas atomization treatment on a dispersing agent, fully mixing two jet flows formed by the gas atomization treatment, collecting, and dispersing in water for ultrasonic dispersion treatment to obtain the aramid micro-nanofiber with the dendritic structure; wherein, the conditions of the gas spray atomization treatment are as follows: the spinneret orifice of the atomizer is an inner air inlet hole and an outer liquid inlet hole (namely, a mode of inner air inlet flow and outer liquid inlet flow is adopted), the aperture range is 0.1-5.0 mm, and the gas pressure range is 0.1-1.0 MPa.
The aramid polymer in the step (1) is at least one of poly (m-phenylene isophthalamide), poly (p-phenylene terephthalamide) and polyamide polymer containing a heterocyclic ring structure; preferably polyisophthaloyl m-phenylenediamine, piperazine aromatic polyamide, piperazine aromatic ring nylon and polyquineAt least one of a quinolinedione amide; more preferably polyisophthaloyl metaphenylene diamine.
The dispersing solvent in the step (1) is one or a mixture of N, N-dimethylacetamide, N-dimethylformamide (dimethyl formamide), dimethyl sulfoxide and acetone; n, N-dimethyl acetamide is preferred.
The concentration of the aramid polymer dispersion liquid in the step (1) is 1-20% by mass; preferably 10-20% by mass; more preferably 12 to 20 mass%.
Stirring in the step (1) is performed by adopting a magnetic stirrer (stirring by using a magnetic rotor) or a paddle type stirrer; preferably, the stirring is carried out using a paddle stirrer.
The stirring conditions in the step (1) are as follows: the rotating speed is 50-10000 rpm, and the stirring time is 1-60 min; preferably: the rotating speed is 500-1000 rpm, and the stirring time is 1-30 min.
The dispersing agent in the step (2) is a solution with a curing effect (a single solvent, or an aqueous solution of a solvent, or other solutions with a curing effect); preferably one or more of N, N-dimethylacetamide, N-dimethylformamide, dimethyl sulfoxide, acetone and water; further preferably water or an N, N-dimethylacetamide solution with the mass percent of 0-90%; more preferably, the water or the N, N-dimethylacetamide solution with a concentration of 10 to 70% by mass.
The conditions for carrying out the air-jet atomization treatment on the aramid polymer dispersion liquid in the step (2) are preferably as follows: the aperture range of the atomizer is 1.0-3.0 mm (more preferably 2.0-3.0 mm); the gas pressure range is 0.2-1.0 MPa.
The conditions for carrying out the air-jet atomization treatment on the dispersing agent in the step (2) are preferably as follows: the aperture range of the atomizer is 1.0-3.0 mm, and the gas pressure range is 0.5-0.8 MPa.
The gas source for the gas-jet atomization treatment in the step (2) is at least one of air, nitrogen and argon; preferably air.
The collection in the step (2) is carried out at a distance of 10-100 cm from a nozzle of the atomizer; preferably, the collection is carried out at a distance of 20-55 cm from a nozzle of the atomizer; more preferably, the collection is carried out at a distance of 20-40 cm from a nozzle of the atomizer; namely, two jets formed in the air-jet atomization treatment are uniformly mixed in the turbulent flow zone, and a disc used for collecting the aramid micro-nanofibers is placed below the turbulent flow zone.
The ultrasonic treatment conditions in the step (2) are as follows: the power is 200-3000W, and the time is 1-200 min; preferably: the power is 1000-3000W, and the time is 5-200 min; more preferably: the power is 1000-2000W, and the time is 5-15 min.
The aramid micro-nano fibers in the step (2) are dendritic, and the width of the aramid micro-nano fibers is less than 150 nm.
The aramid micro-nano fiber with the dendritic structure is prepared by any one of the methods.
The aramid micro-nano fiber with the dendritic structure is applied to the preparation of aramid paper.
The aramid fiber paper is manufactured by the aramid fiber micro-nano fiber with the dendritic structure.
The quantitative amount of the aramid paper is 40g/m2。
The aramid fiber micro-nanofiber with the dendritic structure and/or the aramid fiber paper are applied to composite reinforcing materials, battery diaphragm materials, adsorption filtering materials, electric insulating materials or flexible electronic devices.
The electric insulating material comprises electric insulating nano paper and the like.
The flexible electronic device comprises a flexible electrode and the like.
An atomizer for preparing the aramid micro-nano fiber with the dendritic structure comprises a polymer atomizing device, a curing reagent atomizing device and a receiving disc (8);
the polymer atomization device comprises a polymer negative pressure generation device and a feeding pipe (5-1) used for conveying a polymer, wherein the feeding pipe (5-1) is arranged on one side of the polymer negative pressure generation device, the feeding pipe (5-1) is provided with a polymer discharge port, the polymer negative pressure generation device is provided with a nozzle (9-1), the polymer discharge port is arranged on one side of the nozzle (9-1), and the polymer discharge port and the nozzle (9-1) are arranged in the same direction;
the solidified reagent atomization device comprises a solidified reagent negative pressure generation device and a feeding pipe (5-2) used for conveying a solidified reagent, wherein the feeding pipe (5-2) is arranged on one side of the solidified reagent negative pressure generation device, the feeding pipe (5-2) is provided with a solidified reagent discharge port, the solidified reagent negative pressure generation device is provided with a nozzle (9-2), the solidified reagent discharge port is arranged on one side of the nozzle (9-2), and the solidified reagent discharge port and the nozzle (9-2) are arranged in the same direction;
a collecting tray (8) is arranged below the nozzle (9-1) and the nozzle (9-2), and two jet flows formed by dispersing the polymer and the curing agent are fully mixed into the collecting tray (8).
The nozzle (9-1) of the polymer negative pressure generating device is arranged in the feeding pipe (5-1) in a penetrating way, and the cross section of the polymer discharging port is larger than that of the nozzle (9-1).
The feeding pipe (5-1) comprises a first pipe body and a second pipe body, the first pipe body and the second pipe body are mutually communicated, an included angle between the first pipe body and the second pipe body is smaller than 180 degrees, the polymer discharge port is arranged on the second pipe body, and a nozzle (9-1) of the polymer negative pressure generating device penetrates through the second pipe body.
Preferably, the first pipe body is perpendicular to the second pipe body.
The polymer negative pressure generating device comprises an air compressor (1), an air pipe (3-1) and a pressure regulating valve (2-1), one end of the air pipe (3-1) is connected to the air compressor (1), a nozzle (9-1) is arranged at the other end of the air pipe (3-1), the pressure regulating valve (2-1) is connected to the air pipe (3-1), the air pipe (3-1) penetrates through the second pipe body, and the air pipe (3-1) is parallel to the second pipe body.
The nozzle (9-2) of the solidified reagent negative pressure generating device is arranged in the feeding pipe (5-2) in a penetrating mode, and the cross section of the solidified reagent discharging port is larger than that of the nozzle (9-2).
The feeding pipe (5-1) comprises a third pipe body and a fourth pipe body, the third pipe body is communicated with the fourth pipe body, an included angle between the third pipe body and the fourth pipe body is smaller than 180 degrees, the curing reagent discharging port is formed in the fourth pipe body, and a nozzle (9-2) of the curing reagent negative pressure generating device penetrates through the fourth pipe body.
Preferably, the third pipe is perpendicular to the fourth pipe.
The negative pressure generation device for the curing reagent comprises an air compressor (1), an air pipe (3-2) and a pressure regulating valve (2-2), one end of the air pipe (3-2) is connected to the air compressor (1), a nozzle (9-2) is arranged at the other end of the air pipe (3-2), the pressure regulating valve (2-2) is connected to the air pipe (3-2), the air pipe (3-2) penetrates through a fourth pipe body, and the air pipe (3-2) is parallel to the fourth pipe body.
The nozzle (9-1) and the nozzle (9-2) are nozzles with adjustable calibers.
The polymer atomization device and the solidification reagent atomization device can be symmetrically arranged.
The distance between the receiving tray (8) and the nozzle (9-1) and the distance between the receiving tray and the nozzle (9-2) are adjustable, and preferably 10-100 cm; further preferably 20-55 cm; more preferably 20 to 40 cm.
Compared with the prior art, the invention has the following advantages and effects:
(1) the method comprises the steps of dispersing aramid polymer into spinning solution with a certain concentration by using dimethyl acetamide, carrying out gas atomization treatment, directly and fully mixing two jet flows in a turbulent flow zone after the dispersing agent is subjected to atomization treatment, depositing the jet flows in a collecting disc, and carrying out ultrasonic treatment to obtain aramid micro-nano fibers, namely small polymer grids are formed by dispersion of air flow, and then unique dendritic aramid nano fibers are formed by ultrasonic dispersion; the invention adopts the injection technology of internal air inlet flow and external liquid inlet flow to prepare the aramid micro-nanofibers with controllable size and adjustable network structure, the average diameter of which is less than 150 nm.
(2) According to the invention, liquid substances are disordered and dispersed by the aid of the incoming high-speed flowing compressed gas, the dispersing agent with a solidification effect is atomized, the two substances are fully mixed in a jet flow turbulence area, the aramid micro-nano fibers are obtained in a collecting device (a disc which is arranged at a certain position below the turbulence area and is 10-100 cm away from a jet flow nozzle), the distance range of jet flow passing through a transition area and the turbulence area (the two areas are divided according to the flowing state) can be easily realized by adjusting the concentration of the incoming liquid flow and the pressure of the compressed gas, atomized micro-nano aramid polymer molecular chains are disturbed and dispersed in the turbulent area by receiving airflow, and the aramid micro-nano fibers are stretched and arranged under the action of an airflow field, so that the aramid micro-nano fibers with dendritic structures are obtained, and the size of the micro-nano fibers can be controlled and adjusted.
(3) The micro-nanofiber prepared by the method has a unique dendritic structure and a larger specific surface area, can remarkably improve the bonding strength of the fiber interface in the aramid paper, effectively improves the mechanical strength and dielectric property of the aramid paper, and can be widely applied to the field of new high-end insulating materials.
(4) The invention utilizes the double-jet method to prepare the aramid fiber micro-nanofibers, has simple preparation operation, convenience and easy implementation, has higher production efficiency than the conventional preparation method at present, is suitable for industrialized continuous production, and can be widely applied to the fields of composite reinforcement, battery diaphragms, adsorption filtration, electrical insulation, flexible electrodes and the like.
(5) The preparation technology of the aramid fiber micro-nano fiber is simple to operate, convenient and easy to implement, has higher production efficiency than the conventional preparation method at present, is suitable for industrial continuous production, can replace the existing fibrid production technology, and can obviously improve the dielectric property and the interface bonding property of aramid fiber paper.
(6) The efficient preparation technology of the aramid fiber micro-nano fiber can also increase the functionalization and high performance of the aramid fiber polymer by adding functional elements such as functional nano particles, conductive polymers, heat-conducting fillers and the like into the aramid fiber polymer, and has important significance for the cross diversified application of the aramid fiber micro-nano fiber in various fields such as reinforced materials, battery diaphragms, electrically insulating nano paper, flexible electronic devices, adsorption filter media and the like.
Drawings
Fig. 1 is a schematic diagram of aramid micro-nanofibers prepared by a double-jet method.
FIG. 2 is a schematic diagram of the atomizer device of the present invention (in the figure, 1: air compressor; 2-1 and 2-2: pressure regulating valve; 3-1 and 3-2: air pipe; 4-1 and 4-2: compressed gas flow; 5-1 and 5-2: feed pipe; 6-1: polymer; 6-2: solidifying agent; 7: receiving distance; 8: receiving pan; 9-1 and 9-2: nozzle).
Fig. 3 is a schematic diagram of the jet principle of the aramid micro-nanofibers prepared by the invention.
Fig. 4 is an atomic force microscope measurement diagram of the aramid micro-nanofibers prepared in example 1.
Detailed Description
The present invention will be described in further detail with reference to examples, but the embodiments of the present invention are not limited thereto. Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated. The following examples are given without reference to specific experimental conditions, and generally follow conventional experimental conditions. Unless otherwise specified, reagents and starting materials for use in the present invention are commercially available.
The starting materials for the preparation process of the present invention are commercially available or may be prepared according to prior art methods.
In the present example, aramid polymer (polyisophthaloyl metaphenylene diamine), aramid staple fiber, and aramid pulp were provided by Ganzhou Longbang materials science and technology, Inc.
The performance detection standard of the aramid paper related in the embodiment of the invention is as follows:
thickness (GB/T20628.2-2006); tensile strength (GB/T453-2002); tear strength (GB/T455-2002); electrical strength (GB/T1408.1-2016); dielectric constant and dielectric loss factor (GB/T1409-.
In the embodiment of the present invention, the air-jet atomization treatment was carried out using the following atomizer device (fig. 2):
the atomizer comprises a polymer atomizing device, a curing agent atomizing device and a receiving tray 8;
the polymer atomization device comprises a polymer negative pressure generation device and a feeding pipe 5-1 used for conveying a polymer 6-1, wherein the feeding pipe 5-1 is arranged on one side of the polymer negative pressure generation device, the feeding pipe 5-1 is provided with a polymer discharge port, the polymer negative pressure generation device is provided with a nozzle 9-1, the polymer discharge port is arranged on one side of the nozzle 9-1, and the polymer discharge port and the nozzle 9-1 are arranged in the same direction;
a nozzle 9-1 of the polymer negative pressure generating device is arranged in the feeding pipe 5-1 in a penetrating way, and the cross section of the polymer discharging port is larger than that of the nozzle 9-1;
the feeding pipe 5-1 comprises a first pipe body and a second pipe body, the first pipe body and the second pipe body are mutually communicated, an included angle between the first pipe body and the second pipe body is less than 180 degrees, the polymer discharging port is arranged on the second pipe body, and a nozzle 9-1 of the polymer negative pressure generating device is arranged on the second pipe body in a penetrating mode; preferably, the first pipe body is perpendicular to the second pipe body;
the polymer negative pressure generating device comprises an air compressor 1, an air pipe 3-1 and a pressure regulating valve 2-1, wherein one end of the air pipe 3-1 is connected with the air compressor 1, a nozzle 9-1 is arranged at the other end of the air pipe 3-1, the pressure regulating valve 2-1 is connected with the air pipe 3-1, the air pipe 3-1 penetrates through a second pipe body, and the air pipe 3-1 is parallel to the second pipe body;
the solidified reagent atomization device comprises a solidified reagent negative pressure generation device and a feeding pipe 5-2 used for conveying a solidified reagent 6-2, the feeding pipe 5-2 is arranged on one side of the solidified reagent negative pressure generation device, the feeding pipe 5-2 is provided with a solidified reagent discharge port, the solidified reagent negative pressure generation device is provided with a nozzle 9-2, the solidified reagent discharge port is arranged on one side of the nozzle 9-2, and the solidified reagent discharge port and the nozzle 9-2 are arranged in the same direction;
a nozzle 9-2 of the solidified reagent negative pressure generating device is arranged in the feeding pipe 5-2 in a penetrating way, and the cross section of a solidified reagent discharging port is larger than that of the nozzle 9-2;
the feeding pipe 5-2 comprises a third pipe body and a fourth pipe body, the third pipe body and the fourth pipe body are mutually communicated, an included angle between the third pipe body and the fourth pipe body is less than 180 degrees, a solidified reagent discharging port is formed in the fourth pipe body, and a nozzle 9-2 of a solidified reagent negative pressure generating device penetrates through the fourth pipe body; preferably, the third pipe body is perpendicular to the fourth pipe body;
the negative pressure generating device for the curing reagent comprises an air compressor 1, an air pipe 3-2 and a pressure regulating valve 2-2, wherein one end of the air pipe 3-2 is connected with the air compressor 1, a nozzle 9-2 is arranged at the other end of the air pipe 3-2, the pressure regulating valve 2-2 is connected with the air pipe 3-2, the air pipe 3-2 penetrates through a fourth pipe body, and the air pipe 3-2 is parallel to the fourth pipe body;
the nozzle 9-1 and the nozzle 9-2 are nozzles with adjustable calibers;
a receiving tray 8 is arranged below the nozzle 9-1 and the nozzle 9-2, and two jet flows formed by dispersing the polymer 6-1 and the curing agent 6-2 are fully mixed in the receiving tray 8;
the distance between the receiving tray 8 and the nozzles 9-1 and 9-2 is adjustable, and preferably 10-100 cm; further preferably 20-55 cm; more preferably 20-40 cm;
the polymer atomization device and the solidification reagent atomization device can be symmetrically arranged.
A schematic diagram of the air-jet atomization process using the atomizer device is shown in fig. 3. During operation, the aramid polymer is subjected to air-jet atomization treatment in a mode of internal air inlet flow and external liquid inlet flow, and the method specifically comprises the following steps: the gas forms a compressed gas flow 4-1 through the air compressor 1 and the pressure regulating valve 2-1, the compressed gas flow 4 is ejected from the nozzle 9-1, a negative pressure gas flow zone is formed at the nozzle, and when the polymer 6 passes through the feeding pipe 3, the polymer 6 is disturbed and dispersed; meanwhile, a compressed gas flow is formed by gas through an air compressor 1 and a pressure regulating valve 2-2, the compressed gas flow is ejected from a nozzle 9-2, a negative pressure gas flow area is formed at the position of the nozzle, when a curing reagent 7 passes through a feeding pipe, the curing reagent 6-2 is disturbed and dispersed, a proper receiving distance 7 is adjusted, two jet flows formed by dispersing a polymer 6-1 and the curing reagent 6-2 are fully mixed into a receiving tray 8, and a required aramid fiber micro-nano sample is obtained by collection (the pore sizes of the nozzle 9-1 and the nozzle 9-2 and the pressure sizes of the pressure regulating valves 2-1 and 2-2 can be adjusted to achieve the optimal atomization effect); wherein the gas is one or a mixture of two or more of air, nitrogen and argon (preferably air).
Example 1
The preparation method of the aramid fiber micro-nanofiber by using the double-jet method comprises the following steps (the schematic diagram of the aramid fiber micro-nanofiber prepared by using the double-jet method is shown in figure 1):
(1) preparing an aramid polymer dispersion liquid: dispersing polyisophthaloyl metaphenylene diamine in dimethylacetamide (N, N-dimethylacetamide and DMAC) at room temperature according to mass percent, stirring by a mechanical blade type stirrer at the rotating speed of 500rpm for 10min, and continuously stirring, dispersing and filtering to obtain an aramid polymer dispersion liquid with the mass fraction of 10%;
(2) preparing aramid micro-nano fibers: carrying out gas-jet atomization treatment on the aramid polymer dispersion liquid in a mode of internal gas flow inlet and external liquid flow inlet by adopting an atomizer, wherein the size of an atomization hole is 3.0mm, air is used as a gas source, and the gas pressure is 0.2 MPa; carrying out gas-jet atomization treatment by taking water as a curing reagent (the curing reagent is excessive, the same applies below) in a mode of internal gas flow and external liquid flow, wherein the size of an atomization hole is 1.0mm, air is a gas source, and the gas pressure range is 0.5 MPa; fully mixing in a jet flow turbulent flow region, collecting, enabling a collecting disc device to be 40cm away from a jet flow nozzle, and then dispersing in water for ultrasonic dispersion treatment with the power of 1000W and the time of 20min to obtain aramid micro-nano fibers; the size and the specific surface area of the prepared aramid micro-nanofibers are characterized;
(3) the prepared aramid micro-nano fiber is made into micro-nano fiber with the quantitative of 40g/m2The aramid fiber paper comprises the following aramid fiber chopped fibers in percentage by mass: aramid pulp: the thickness of the aramid fiber paper prepared by hot pressing the aramid fiber micro-nano fiber at 200 ℃ is 0.05mm, wherein the aramid fiber micro-nano fiber is 5:4: 1.
Example 2
The method for efficiently preparing the aramid micro-nanofibers by using the double-jet method comprises the following steps:
(1) preparing an aramid polymer dispersion liquid: dispersing polyisophthaloyl metaphenylene diamine in dimethylacetamide at room temperature according to the mass percentage, stirring by a mechanical paddle type stirrer at the rotating speed of 500rpm for 20min, and continuously stirring, dispersing and filtering to obtain an aramid polymer dispersion liquid with the mass fraction of 20%;
(2) preparing aramid micro-nano fibers: carrying out gas-jet atomization treatment on the aramid polymer dispersion liquid in a mode of internal gas flow inlet and external liquid flow inlet by adopting an atomizer, wherein the size of an atomization hole is 3.0mm, air is used as a gas source, and the gas pressure is 1.0 MPa; performing gas-jet atomization treatment by taking a dimethylacetamide solution with the mass fraction of 10% as a curing reagent in a mode of internal gas flow and external liquid flow, wherein the size of an atomization hole is 2.0mm, air is used as a gas source, and the gas pressure range is 0.6 MPa; fully mixing in a jet flow turbulent flow region, collecting a disc device which is 20cm away from a jet flow nozzle, dispersing in water for ultrasonic dispersion treatment with the power of 3000W and the time of 5min to obtain aramid micro-nano fibers; the size and the specific surface area of the prepared aramid micro-nanofibers are characterized;
(3) the prepared aramid micro-nano fiber is made into micro-nano fiber with the quantitative of 40g/m2The aramid fiber paper comprises the following aramid fiber chopped fibers in percentage by mass: aramid pulp: the thickness of the aramid fiber micro-nano fiber paper is 0.05mm after the aramid fiber micro-nano fiber is subjected to hot pressing at 200 ℃.
Example 3
The method for efficiently preparing the aramid micro-nanofibers by using the double-jet method comprises the following steps:
(1) preparing an aramid polymer dispersion liquid: dispersing polyisophthaloyl metaphenylene diamine in dimethylacetamide at room temperature according to the mass percentage, stirring by a mechanical paddle type stirrer at the rotating speed of 1000rpm for 1min, and continuously stirring, dispersing and filtering to obtain an aramid polymer dispersion liquid with the mass fraction of 12%;
(2) preparing aramid micro-nano fibers: carrying out gas-jet atomization treatment on the aramid polymer dispersion liquid in a mode of internal gas flow inlet and external liquid flow inlet by adopting an atomizer, wherein the size of an atomization hole is 2.0mm, air is a gas source, and the gas pressure is 0.4 MPa; performing gas-jet atomization treatment by taking a dimethylacetamide solution with the mass fraction of 70% as a curing reagent in a mode of internal gas flow and external liquid flow, wherein the size of an atomization hole is 3.0mm, air is used as a gas source, and the gas pressure range is 0.8 MPa; fully mixing in a jet flow turbulent flow region, collecting a disc device which is 55cm away from a jet flow nozzle, dispersing in water for ultrasonic dispersion treatment with the power of 1000W and the time of 200min to obtain aramid micro-nano fibers; the size and the specific surface area of the prepared aramid micro-nanofibers are characterized;
(3) the prepared aramid micro-nano fiber is made into micro-nano fiber with the quantitative of 40g/m2The aramid fiber paper comprises the following aramid fiber chopped fibers in percentage by mass: aramid pulp: the thickness of the aramid fiber paper prepared by hot pressing the aramid fiber micro-nano fiber at 200 ℃ is 0.05mm, wherein the aramid fiber micro-nano fiber is 5:3: 2.
Example 4
The method for efficiently preparing the aramid micro-nanofibers by using the double-jet method comprises the following steps:
(1) preparing an aramid polymer dispersion liquid: dispersing polyisophthaloyl metaphenylene diamine in dimethylacetamide at room temperature according to the mass percentage, stirring by a mechanical paddle type stirrer at the rotating speed of 1000rpm for 30min, and continuously stirring, dispersing and filtering to obtain an aramid polymer dispersion liquid with the mass fraction of 12%;
(2) preparing aramid micro-nano fibers: carrying out gas-jet atomization treatment on the aramid polymer dispersion liquid in a mode of internal gas flow inlet and external liquid flow inlet by adopting an atomizer, wherein the size of an atomization hole is 2.0mm, air is used as a gas source, and the gas pressure is 0.6 MPa; performing gas-jet atomization treatment by taking a dimethylacetamide solution with the mass fraction of 20% as a curing reagent in a mode of internal gas flow and external liquid flow, wherein the size of an atomization hole is 2.0mm, air is used as a gas source, and the gas pressure range is 0.6 MPa; fully mixing in a jet flow turbulent flow region, collecting, and dispersing in water for ultrasonic dispersion treatment with power of 2000W and time of 15min by using a collecting disc device at a distance of 45cm from a jet flow nozzle to obtain aramid micro-nano fibers; the size and the specific surface area of the prepared aramid micro-nanofibers are characterized;
(3) the prepared aramid micro-nano fiber is made into micro-nano fiber with the quantitative of 40g/m2The aramid fiber paper comprises the following aramid fiber chopped fibers in percentage by mass: aramid pulp: the thickness of the aramid fiber paper prepared by hot pressing the aramid fiber micro-nano fiber at 200 ℃ is 0.05mm, wherein the aramid fiber micro-nano fiber is 5:2: 3.
Comparative example 1
The preparation method of the aramid micro-nano fiber comprises the following steps:
(1) preparing an aramid polymer dispersion liquid: dispersing polyisophthaloyl metaphenylene diamine in a dimethylacetamide solution at room temperature according to the mass percentage, stirring by a magnetic rotor stirrer at the rotating speed of 50rpm for 60min, and continuously stirring, dispersing and filtering to obtain an aramid polymer dispersion liquid with the mass fraction of 0.1%;
(2) preparing aramid micro-nano fibers: by adopting the atomizer device, the aramid polymer dispersion liquid is subjected to air-jet atomization treatment in a mode of internal air inlet fluid flow and external liquid inlet fluid flow, the size of an atomization hole is 5.0mm, air is used as an air source, the air pressure is 0.15MPa, the aramid polymer dispersion liquid is directly sprayed into water, then ultrasonic dispersion treatment is carried out, the power is 200W, and the time is 30min, so that the aramid micro-nanofiber is obtained; the size and the specific surface area of the prepared aramid fiber micro-nano fiber are represented;
(3) the prepared aramid micro-nano fiber is made into micro-nano fiber with the quantitative of 40g/m2The aramid fiber paper comprises the following aramid fiber chopped fibers in percentage by mass: aramid pulp: the thickness of the aramid fiber micro-nano fiber paper is 0.05mm after the aramid fiber micro-nano fiber is subjected to hot pressing at 200 ℃.
Effects of the embodiment
The sizes and specific surface areas of the aramid micro-nanofibers prepared in examples 1 to 4 and comparative example 1 were characterized, and the aramid papers prepared in examples 1 to 4 and comparative example 1 were subjected to a performance test (blank control: by mass: blank control)Proportion aramid chopped fiber: aramid pulp is 5:5, and base paper (the quantitative is 40 g/m) is manufactured by Kaiser method sheet making2)。
An atomic force microscope measurement chart of the aramid micro-nanofibers prepared in example 1 is shown in fig. 4, and other test results are shown in table 1.
TABLE 1 summary table of testing results of aramid micro-nanofibers and aramid paper
As can be seen from table 1, the aramid micro-nanofibers prepared by the double-jet method have significant application effects and wide application prospects in the field of high-performance aramid paper.
The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, and simplifications are intended to be included in the scope of the present invention.