Preparation method of novel meta-aramid nano particles
A one-step self-assembly process for interlaced PPPA nanoparticles from spinning dope using solvents like DMAC, DMSO, or DMF addresses the high cost and complexity of traditional methods, reducing production costs and expanding the applicability of interlaced PPPA.
Patent Information
- Application Number
- CN202510555757.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-29
- Publication Date
- 2025-07-15
AI Technical Summary
Meta-aramid nanoification technology is not yet mature, and the traditional methods are complex and expensive, which limits their wide application.
The one-step self-assembly technology is adopted to directly form nanoparticles based on the aramid spinning raw liquid by solvent self-assembly, eliminating the spinning and subsequent peeling steps, and reducing production costs through hydrogen bonding as the self-assembly power.
Significantly simplify the process path, reduce production costs, broaden application fields, and promote the development of meta-aramid technology.
Smart Images
Figure CN120309990A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of the preparation of nanocomposites, and particularly to a preparation method of a novel meta-aramid nanoparticle. Background Art
[0002] The development direction of meta-aramid technology will be the same as that of other high-performance fibers, following the technology of low cost, high performance, and differentiated products. This preparation method of the novel meta-aramid nanoparticle makes the technology more cost-effective and is helpful to a certain extent for the further production of meta-aramid.
[0003] However, one reason restricting the expanded application of high-tech fibers such as meta-aramid is the high cost. Currently, the methods for aramid nanosizing mostly focus on para-aramid (such as ), and usually, fibers need to be formed through a spinning process first, and then they are nanosized by mechanical peeling or chemical treatment. However, the nanosizing technology of meta-aramid (such as ) is not yet mature, and the traditional method involves post-spinning treatment steps, with a complex process and high cost. There is an urgent need to develop a preparation method of a novel meta-aramid nanoparticle that can solve the above problems. Summary of the Invention
[0004] In view of the characteristics of meta-aramid, the present invention directly starts from the spinning dope, forms nanoparticles through self-assembly, omits the traditional spinning step, significantly simplifies the process route and reduces the cost. Therefore, through this novel preparation method of meta-aramid nanoparticles, one-step self-assembly can reduce the production cost of meta-aramid, lower its product price, and further broaden the application field, expand the market coverage rate, and promote the development of meta-aramid technology.
[0005] To solve the limitation that the nanosizing of meta-aramid relies on post-spinning treatment, the present invention proposes a one-step self-assembly technology without spinning. Using aramid spinning dope as a precursor, a good / poor solvent self-assembly method is adopted to regulate and prepare novel aramid nanoparticles, reduce the preparation cost of aramid nanoparticles, and break through the bottleneck of traditional processes.
[0006] To achieve the purpose of the present invention, the present invention provides a preparation method of a novel meta-aramid nanoparticle, including the following steps:
[0007] (1) Meta-aramid and an organic solvent are pre-stirred, then placed in an ultrasonic instrument for ultrasonic treatment for a certain time, and then transferred to a high-speed stirrer for continuous stirring to ensure sufficient dispersion and form a uniform dilution;
[0008] (2) The dilution is transferred to a constant-temperature magnetic stirrer, and under stirring conditions, deionized water is slowly added dropwise thereto until the solution suddenly becomes turbid, and then the addition is stopped;
[0009] (3) After allowing the turbid solution to stand for a certain period of time, stir it at high speed for a certain period of time to ensure the uniform dispersion of the nanoparticles. Then, use a vacuum filtration device for filtration and washing to remove the residual solvent. After drying, aramid nanoparticles are obtained.
[0010] The organic solvent is at least one of DMAC, DMSO, and DMF.
[0011] Furthermore, the meta-aramid is poly(m-phenylene isophthalamide), and its chemical formula is [-NH-C6H4-NH-CO-C6H4-CO-]. n .
[0012] Furthermore, the mass ratio of the meta-aramid to the organic solvent is 1:(1 - 8), preferably 1:4.
[0013] Furthermore, in (2), the deionized water is added in batches. In the early stage, the amount of water added each time is 5% of the mass of the dilution solution, and it is added twice with an interval of 5 minutes between the additions. Observe the state of the solution. When the solution changes from transparent to light blue, adjust the dropping speed to: 1% of the mass of the dilution solution each time, until the solution suddenly becomes turbid, then stop dropping.
[0014] Furthermore, in step (3), the standing time is greater than 12 h, and the high-speed stirring time is greater than 3 h.
[0015] Furthermore, in step (1), the ultrasonic time is 15 min - 30 min, and the high-speed stirring time is greater than 4 h.
[0016] The present invention also provides the application of the novel meta-aramid nanoparticles obtained by the above preparation method in the preparation of aramid nanofibers.
[0017] Furthermore, the application is as follows: By means of stirring, the novel meta-aramid nanoparticle aqueous solution is compounded with sodium alginate and extruded and spun to obtain aramid nanofibers.
[0018] Even further, the mass concentration of the novel meta-aramid nanoparticle aqueous solution is 0.5% - 3%.
[0019] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:
[0020] By means of the solvent-induced self-assembly technology, using hydrogen bonds as the driving force for one-step self-assembly, nanoparticles are directly formed from the meta-aramid spinning dope in one step, completely omitting the traditional spinning and subsequent peeling steps, significantly reducing equipment investment, shortening the production cycle, and reducing energy consumption (such as the energy consumption of the spinning process). There is no acid harmful to the environment during the reaction process. Description of the Drawings
[0021] Figure 1Sample picture of the aramid nanofiber solution obtained in Example 1;
[0022] Figure 2 SEM image of the aramid nanofibers obtained in Example 1;
[0023] Figure 3 Particle size test chart of the aramid nanofibers obtained in Examples 1-3;
[0024] Figure 4 Fourier transform infrared spectrum of the aramid nanofibers obtained in Example 1;
[0025] Figure 5 X-ray diffraction spectrum of the aramid nanofibers obtained in Example 1;
[0026] Figure 6 shows the mechanical properties of the composite fiber of aramid nanofibers and sodium alginate in Application Example 1;
[0027] Figure 7 Corresponding picture of Comparative Example 1. The left picture shows the dissolution of aramid in DMAC in Example 1, and the right picture shows the dissolution of aramid in pure water without adding DMAC;
[0028] Figure 8 Corresponding picture of Comparative Example 2. The left picture shows the solution picture after standing in Example 1, and the right picture shows the directly stirred solution picture. Detailed implementation manners
[0029] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following will combine with some representative embodiments to detail the technical solutions according to the present invention.
[0030] Example 1 A preparation method of a novel meta-aramid nanofiber, the specific steps are as follows:
[0031] (1) Take a 150 mL beaker, add 15 g of meta-aramid (poly(m-phenylene isophthalamide), model T462, chemical formula: [-NH-C6H4-NH-CO-C6H4-CO-] n ) and 60 g of DMAC (dimethylacetamide), control the stirring rate at 800 rpm, initially stir continuously for 1 h, then place the mixture in an ultrasonic instrument, ultrasonically treat it at a frequency of 40 kHz for 25 minutes, and then transfer it to a high-speed stirrer (rotation speed 2000 rpm) and stir for 5 hours to ensure sufficient dispersion and form a uniform 20% dilution.
[0032] (2) Transfer the diluent to a thermostatic magnetic stirrer. Under the stirring conditions of 25 °C and 500 rpm, slowly add deionized water to it in batches. The amount of water added each time is 5% of the mass of the diluent (i.e., 3.75 g of water is added each time), and it is added twice with an interval of 5 minutes between additions. Observe the state of the solution. When the solution changes from transparent to light blue, adjust the dropping speed to: 1% of the mass of the diluent added each time (i.e., 0.75 g of water is added each time) until the solution suddenly becomes turbid (the critical point is reached), and then stop adding. In this example, the total amount of water added throughout the process is 15% of the mass of the diluent.
[0033] (3) Let the turbid solution stand for 12 hours, and then stir it at a high speed of 2500 rpm for 4 hours to ensure the uniform dispersion of the nanoparticles. Use a vacuum filtration device (filter membrane pore size 0.22 μm) to perform filtration 3 times. After each filtration, wash it with deionized water to remove the residual solvent, and obtain aramid nanoparticles after drying.
[0034] Perform Fourier transform infrared spectroscopy (FTIR) tests on the dried aramid nanoparticle powder. The resolution of the FTIR is 4 cm -1 , and the test wavenumber range is 4000 - 400 cm -1 , the number of scans is 32 scans, and the results are shown in Figure 4 . Through infrared spectrum characterization, analyze the absorption peaks in the spectrum. At a wavenumber of 3348 cm -1 , there is an obvious absorption peak, which corresponds to the stretching vibration peak of the O-H bond. The O-H bond is a characteristic functional group of meta-aramid. At a wavenumber of -1639 cm -1 , a smaller absorption peak can also be observed, which is related to the stretching vibration of the -C=O- bond. At a wavenumber of -1089 cm -1 , there is an obvious absorption peak, which is the stretching vibration peak of -C-N-. The presence of these three absorption peaks indicates that meta-aramid has a typical chemical structure and molecular composition.
[0035] Through the X-ray diffraction pattern, the diffraction peaks of the aramid nanoparticles are located at 18.25°, 23.57°, 27.73° and 42.02°. By calculation, the crystallinity of the aramid nanoparticles is 40.3%.
[0036] Example 2
[0037] The raw materials, dosages and experimental procedures used in the experiment are the same as those in Example 1, except that DMAC is replaced with an equal amount of DMSO as the solvent for dissolving meta-aramid, and the average particle size of the aramid nanoparticles is 601 nm.
[0038] Example 3
[0039] The raw materials, dosages, and experimental procedures used during the experiment were the same as those in Example 1, except that DMF was selected as the solvent for dissolving meta-aramid to obtain an aramid nanoparticle solution. The average particle size of the aramid nanoparticles was 632 nm.
[0040] Comparative Example 1
[0041] The raw materials, dosages, and experimental procedures used during the experiment were the same as those in Example 1, except that DMAC was not added in step (1). Figure 7 Corresponding to step (1) of Example 1 and Comparative Example 1, where DMAC was added on the left and the dissolution was good, and on the right, DMAC was not added and deionized water was added, resulting in poor dissolution. In this comparative example, N,N-dimethylacetamide (DMAC) is a good solvent for aramid, and there is a strong interaction (i.e., solvation) between the aramid segments and DMA molecules. Deionized water is a poor solvent for aramid. When it comes into contact with aramid, only partial dissolution may occur, and the rest may cause aramid to form a gel and precipitate. This shows that DMAC is a key part in this step.
[0042] Comparative Example 2
[0043] The raw materials, dosages, and experimental procedures used during the experiment were the same as those in Example 1, except that the turbid solution was not allowed to stand for 12 hours in step (3) and was directly stirred. Figure 8 Corresponding to step (3) of Example 1 and Comparative Example 2, where a gel formed from the turbid solution after standing for 12 hours is on the left, and the solution obtained by directly rotating at high speed without standing is on the right. In this comparative example, after the solution reaches the critical point, due to the presence of self-assembly driving force, the aramid nanoparticles need to be free from the influence of stirring to spontaneously assemble into an ordered structure. 12 hours is a necessary condition for its full spontaneous assembly. If directly stirred at high speed, the self-assembly driving force between the aramid nanoparticles is destroyed, the solution will always be at the critical point, unable to form an ordered structure inside, and will always be in a solution state. This shows that standing for 12 hours is a key step in this method.
[0044] Application Example 1
[0045] The aramid nanofibers prepared in Example 1 were selected and added to deionized water to form an aramid nanofiber dispersion, which was diluted to concentrations of 0.5 wt%, 1 wt%, 2 wt%, and 3 wt% respectively. Then, it was compounded with sodium alginate (hereinafter referred to as CA) by stirring and extruded to obtain composite fibers (hereinafter referred to as ANP). The specific compounding method was as follows: The four aramid nanofiber dispersions with different concentrations were stirred at high speed, and 3% of the sodium alginate powder by mass of the dispersion was slowly poured in. After stirring for 3 h, the solution became uniform. Hydrogen bonds were formed by the cross-linking of sodium alginate molecules and aramid molecules, and the mechanical properties of the composite fibers were improved under the action of hydrogen bonds. As shown in Figure 6, where CA3 represents an aqueous solution of 3 wt% sodium alginate. From the perspective of mechanical properties, adding ANP to CA would improve the mechanical properties of the fibers. Among them, the fiber properties of ANP1% were improved most significantly, with a tensile strength of 153.39 MPa and a toughness of 2440.30 KJ / m 3 , and the tensile strength and toughness were increased by 77.78% and 61.34% respectively. However, the mechanical properties of ANP-2% and ANP-3% fibers decreased instead because the large amount of ANP agglomerated and was unevenly distributed, which reduced the mechanical properties. Therefore, the mechanical properties of the composite fibers can be improved after blending aramid nanofibers with sodium alginate.
Claims
1. A preparation method of a novel meta-aramid nanoparticle, comprising the following steps: (1) After pre-stirring meta-aramid and an organic solvent, place them in an ultrasonic instrument for ultrasonic treatment for a certain time, and then transfer them to a high-speed stirrer to continue stirring to ensure sufficient dispersion and form a uniform dilution; (2) Transfer the dilution to a constant-temperature magnetic stirrer. Under stirring conditions, slowly add deionized water thereto until the solution suddenly becomes turbid, and then stop adding; (3) After standing the turbid solution for a certain time, stir at high speed for a certain time to ensure uniform dispersion of the nanoparticles. Use a vacuum filtration device for filtration and washing to remove the residual solvent, and dry to obtain aramid nanoparticles; The organic solvent is at least one of DMAC, DMSO, and DMF.
2. The preparation method according to claim 1, characterized in that, The meta-aramid is poly(m-phenylene isophthalamide), chemical formula: [-NH-C6H4-NH-CO-C6H4-CO-] n .
3. The preparation method according to claim 1, characterized in that, The mass ratio of the meta-aramid to the organic solvent is 1:(1 - 8).
4. The preparation method according to claim 1, characterized in that, In (2), the deionized water is added in batches. The amount of water added each time in the early stage is 5% of the mass of the dilution, and it is added twice with an interval of 5 minutes between the additions. Observe the state of the solution. When the solution changes from transparent to light blue, adjust the dropping speed to: 1% of the mass of the dilution each time until the solution suddenly becomes turbid and stop adding.
5. The preparation method according to claim 1, characterized in that, In step (3), the standing time is greater than 12 h, and the high-speed stirring time is greater than 3 h.
6. The preparation method according to claim 1, wherein In step (1), the ultrasonic time is 15 min - 30 min, and the high-speed stirring time is greater than 4 h.
7. Application of the novel meta-aramid nanoparticle obtained by the preparation method according to any one of claims 1 - 6 in the preparation of aramid nanofibers.
8. The application according to claim 7, wherein The application is: By means of stirring, the novel meta-aramid nanoparticle aqueous solution is compounded with sodium alginate and extruded and spun to obtain aramid nanofibers.