A method for preparing fluorescent nylon 12
Fluorescent nylon 12 was prepared by mixing a fluorescent precursor with nylon 12 in an extruder, which solved the problem of high energy consumption in nylon 12 production, improved fluorescence performance, and expanded the range of applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BEIJING UNIV OF CHEM TECH
- Filing Date
- 2026-03-18
- Publication Date
- 2026-06-02
AI Technical Summary
In the existing technology, the production process of nylon 12 has problems of high energy consumption and resource consumption, and it has failed to effectively combine carbon dots with nylon 12 to improve its fluorescence performance.
Fluorescent nylon 12 with different fluorescent colors was prepared by mixing fluorescent precursors with nylon 12 and then melting and reacting them in an extruder, combined with the carbon dot generation process.
The fluorescence intensity of Nylon 12 was improved, its application range was expanded, and Nylon 12 with different fluorescent colors was obtained while maintaining its mechanical properties.
Smart Images
Figure CN122127779A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of nylon, and more particularly to a method for preparing fluorescent nylon 12. Background Technology
[0002] Currently, the demand for nylon recycling is constantly increasing. Nylon (PA) 12 is a long-chain nylon with high molecular chain flexibility. Due to its high crystallinity, high strength, low water absorption, good low-temperature resistance, good airtightness, excellent alkali resistance, good oil and fat properties, and good mechanical and electrical properties, it is the most widely used long-chain nylon. Compared with another long-chain nylon material, PA11, the price of butadiene, the raw material for PA12, is only one-third that of castor oil, the raw material for PA11. It can replace PA11 in most applications, with wide applications in automotive fuel lines, air brake hoses, submarine cables, 3D printing, and many other fields. The market demand for nylon 12 is expected to reach 500,000 tons, but the high energy consumption and resource consumption problems in its production process are becoming increasingly prominent. Therefore, how to improve its renewability and recyclability through technological innovation has become a key research direction.
[0003] Carbon quantum dots (CDs) are quasi-spherical nanoparticles with a diameter of less than 10 nm, typically containing numerous functional groups such as carboxyl and hydroxyl groups on their surface. Since their initial discovery in 2004, many methods for synthesizing carbon quantum dots have been developed, primarily including solvothermal synthesis, chemical oxidation, combustion, and electrochemical methods. Pyrolysis is a widely used method for preparing carbon quantum dots. Organic matter in the carbon source gradually transforms into carbon quantum dots through processes such as high-temperature heating, dehydration, degradation, and carbonization in a vacuum or inert gas environment. In pyrolysis, high concentrations of acid or alkali are typically used to break down the carbon precursor into nanoparticles. Various biomass raw materials, including watermelon rinds, coffee grounds, and plant leaves, can be used as carbon sources to prepare carbon quantum dots via pyrolysis. By changing the pyrolysis conditions, such as pyrolysis temperature, pyrolysis time, and the pH of the reaction system, the properties of the obtained carbon quantum dots can be adjusted, resulting in carbon dots with different fluorescent colors.
[0004] Fluorescent nylon 12 can be obtained by combining nylon 12 with carbon dots, but no studies have yet linked the two together. Summary of the Invention
[0005] This invention provides a method for preparing fluorescent nylon 12, increasing the fluorescence intensity of nylon 12. By combining the generation of carbon dots and the extrusion process of nylon 12, fluorescent nylon 12 with different fluorescent colors is obtained. This invention relates to fluorescent nylon 12 and its preparation method. This invention obtains fluorescent nylon 12 with different fluorescent colors and high fluorescence intensity by changing the type, ratio, and amount of precursor and mixing it with nylon 12, followed by extrusion in an extruder.
[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: This invention provides a method for preparing fluorescent nylon 12, comprising the following steps: Fluorescent precursor and nylon 12 are mixed, melted and reacted to obtain fluorescent nylon 12.
[0007] Preferably, the mass ratio of the fluorescent precursor to the nylon 12 is 1:200 to 1:2000.
[0008] Preferably, the fluorescent precursor includes at least one of citric acid, 3,9-perylene acid, 1,6-hexanediamine, and neutral red.
[0009] Preferably, the melting temperature is 180~190℃.
[0010] Preferably, the reaction temperature is 190~220℃.
[0011] Preferably, the preparation method of fluorescent nylon 12 specifically includes: The fluorescent precursor and nylon 12 were mixed and then transferred to an extruder. The mixture was first melted in the extruder and then mixed and reacted in the screw of the extruder to obtain fluorescent nylon 12.
[0012] The method for preparing fluorescent nylon 12 provided by the present invention can be obtained by extrusion reaction in an extruder, and the preparation method is simple.
[0013] A second aspect of the present invention also provides fluorescent nylon 12 prepared by the above-described method.
[0014] Preferably, the fluorescent nylon 12 has fluorescent colors including blue, green, and yellow.
[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention innovatively combines the preparation process of carbon dots with the processing technology of nylon 12, and obtains fluorescent nylon 12 by one-step extrusion reaction through an extruder.
[0016] (2) By changing the types and proportions of precursors, fluorescent nylon 12 with different fluorescent colors was obtained in one step, further expanding the application range of nylon 12. Attached Figure Description
[0017] The above and other objects, features, and advantages of the invention will be apparent from the following description of preferred embodiments illustrating the gist of the invention and its use, and the accompanying drawings, in which: Figure 1The image shows the characterization of fluorescent nylon 12 in Example 1, where a is a physical image before and after UV irradiation, b is a chromaticity diagram, and c is a fluorescence emission spectrum.
[0018] Figure 2 The image shows the characterization of fluorescent nylon 12 in Example 2, where a is a physical image before and after UV irradiation, b is a chromaticity diagram, and c is a fluorescence emission spectrum.
[0019] Figure 3 The image shows the characterization of fluorescent nylon 12 in Example 3, where a is a physical image before and after UV irradiation, b is a chromaticity diagram, and c is a fluorescence emission spectrum.
[0020] Figure 4 The FTIR spectra of fluorescent nylon 12 and nylon 12 (PA12) in Examples 1-3 are shown. 1 H-NMMR spectra, where a is the FTIR spectrum and b is the H-NMMR spectrum. 1 H-NMR spectrum.
[0021] Figure 5 The fluorescence lifetime distribution diagrams are shown for fluorescent nylon 12 in Examples 1-3.
[0022] Figure 6 The stress-strain curves of fluorescent nylon 12 and nylon 12 (PA12) in Examples 1-3 are shown.
[0023] Figure 7 The figures show the secondary heating curves and crystallization curves of fluorescent nylon 12 and nylon 12 (PA12) in Examples 1-3, where a is the secondary heating curve and b is the crystallization curve. Detailed Implementation
[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. The embodiments of this application are only examples, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0025] Example 1 A fluorescent nylon 12 and its preparation method, comprising: (1) Mix 3 parts citric acid, 6 parts hexamethylenediamine and 1800 parts nylon 12 evenly and add them to the extruder. First, melt at a high temperature of 190°C, then mix thoroughly in a screw at 200°C and react for 0.5 h to finally obtain fluorescent nylon 12, which is denoted as BFPA12.
[0026] Figure 1 Image a shows the fluorescent nylon 12 BFPA12 prepared in Example 1 before and after UV irradiation. Figure 1In the diagram, b represents the chromaticity diagram of BFPA12 (CIE1931). The actual image shows that the obtained fluorescent nylon 12 exhibits blue fluorescence, with coordinates (0.15884, 0.12339) on the chromaticity diagram, indicating a blue color. Figure 1 Figure c shows the fluorescence emission spectrum of fluorescent nylon 12 prepared in Example 1. The changes in fluorescence intensity curves before and after the addition of the precursor show that, compared to pure nylon 12, the fluorescence intensity of fluorescent nylon 12 prepared in Example 1 was improved, with a red shift in the peak, and the fluorescence color changed from a purplish-blue to a deeper blue.
[0027] Example 2 A fluorescent nylon 12 and its preparation method, comprising: (1) Mix 1 part citric acid, 3 parts neutral red and 4000 parts nylon 12 evenly and add them to the extruder. First melt at 190°C, then mix thoroughly in a screw at 200°C and react for 0.5h to finally obtain the desired fluorescent nylon 12, denoted as YFPA12.
[0028] Figure 2 Image a shows the fluorescent nylon 12 YFPA12 prepared in Example 2 before and after UV irradiation. Figure 2 In the diagram, b represents the chromaticity diagram of YFPA12 (CIE1931). The actual image shows that the obtained fluorescent nylon 12 exhibits yellow fluorescence, with coordinates (0.45607, 0.54148) on the chromaticity diagram, indicating a yellow color. Figure 2 Figure c shows the fluorescence emission spectrum of the fluorescent nylon 12 prepared in Example 2. The changes in fluorescence intensity curves before and after the addition of the precursor show that the fluorescence intensity of the fluorescent nylon 12 prepared in Example 2 is significantly improved compared to pure nylon 12, with a peak at 567 nm and a yellow fluorescence color.
[0029] Example 3 A fluorescent nylon 12 and its preparation method, comprising: (1) Mix 1 part of 3,9-perylene acid and 2000 parts of nylon 12 evenly and add them to the extruder. First, melt them at 180°C, then mix them evenly in the screw at 190°C and react for 0.5h to finally obtain the desired fluorescent nylon 12, which is denoted as GFPA12.
[0030] Figure 3 Image a shows the fluorescent nylon 12 GFPA12 prepared in Example 3 before and after UV irradiation. Figure 3 In the image, b represents the chromaticity diagram of GFPA12 (CIE1931). The actual image shows that the obtained fluorescent nylon 12 exhibits green fluorescence, with coordinates (0.16172, 0.59874) on the chromaticity diagram, indicating a green color. Figure 3 Figure c shows the fluorescence emission spectrum of fluorescent nylon 12 prepared in Example 3. The changes in fluorescence intensity curves before and after the addition of the precursor show that the fluorescence intensity of fluorescent nylon 12 prepared in Example 3 is significantly improved compared to pure nylon 12, with a peak at 512 nm and a green fluorescence color.
[0031] Figure 4 In Figure a, the FTIR spectra of fluorescent nylon 12 and nylon 12 (PA12) prepared in Examples 1-3 of the present invention are shown. Figure 4 In the middle b, fluorescent nylon 12 and nylon 12 (PA12) prepared in Examples 1-3 of the invention are used. 1 1H-NMR spectrum. 5 mg of fluorescent nylon 12 prepared in Examples 1-3 of the present invention was dissolved in 10 mL of concentrated sulfuric acid. The viscosity values are shown in Table 1. Comparing the infrared, NMR, and viscosity data before and after the addition of the precursor, it can be seen that compared to pure nylon 12, the addition of the precursor has virtually no effect on the structure of nylon 12, but instead increases its viscosity.
[0032] Table 1
[0033] Figure 5 The fluorescence lifetime distribution diagrams of fluorescent nylon 12 prepared in Examples 1-3 of this invention are shown. The fluorescence lifetime (τ) was obtained through fitting calculations. The τ values for blue fluorescent nylon 12 (BFPA12), yellow fluorescent nylon 12 (YFPA12), and green fluorescent nylon 12 (GFPA12) were 9.35 ns, 8.21 ns, and 6.10 ns, respectively.
[0034] Figure 6 The stress-strain curves of fluorescent nylon 12 and nylon 12 (PA12) prepared in Examples 1-3 of the invention are shown. Comparing the data before and after the addition of the precursor, it can be seen that the addition of the precursor has a smaller impact on the mechanical properties compared with pure nylon 12.
[0035] Figure 7 In Figure a, the secondary heating curves of fluorescent nylon 12 and nylon 12 (PA12) prepared in Examples 1-3 of the present invention are shown. Figure 7 Table b shows the crystallization curves of fluorescent nylon 12 and nylon 12 (PA12) prepared in Examples 1-3 of the invention. The calculated enthalpy of melting and enthalpy of crystallization are shown in Table 2. Comparing the melting and crystallization data before and after the addition of the precursor, it can be seen that compared with pure nylon 12, the addition of the precursor lowers the melting temperature of nylon 12 and increases the enthalpy of melting; it also significantly increases the crystallization temperature and enthalpy of crystallization.
[0036] Table 2
[0037] In summary, this invention yields fluorescent nylon 12 by mixing a precursor and nylon 12 and then extruding the mixture in an extruder. The fluorescence intensity of fluorescent nylon 12 is significantly improved compared to pure nylon 12. Furthermore, different colors of fluorescent nylon 12 can be obtained by changing the type, ratio, and amount of the precursor. The prepared fluorescent nylon 12 maintains its original structure and mechanical properties while exhibiting strong fluorescence intensity.
[0038] Although preferred embodiments of the invention have been shown and described, it is conceivable that those skilled in the art can devise various modifications to the invention within the spirit and scope of the appended claims.
Claims
1. A method for preparing fluorescent nylon 12, characterized in that, Includes the following steps: Fluorescent precursor and nylon 12 are mixed, melted and reacted to obtain fluorescent nylon 12.
2. The method for preparing fluorescent nylon 12 according to claim 1, characterized in that, The mass ratio of the fluorescent precursor to the nylon 12 is 1:200 to 1:2000.
3. The method for preparing fluorescent nylon 12 according to claim 1, characterized in that, The fluorescent precursor includes at least one of citric acid, 3,9-perylene acid, 1,6-hexanediamine, and neutral red.
4. The method for preparing fluorescent nylon 12 according to claim 1, characterized in that, The melting temperature is 180~190℃.
5. The method for preparing fluorescent nylon 12 according to claim 1, characterized in that, The reaction temperature is 190~220℃.
6. The method for preparing fluorescent nylon 12 according to claim 1, characterized in that, Specifically, it includes: The fluorescent precursor and nylon 12 were mixed and then transferred to an extruder. The mixture was first melted in the extruder and then mixed and reacted in the screw of the extruder to obtain fluorescent nylon 12.
7. Fluorescent nylon 12 prepared by the method of any one of claims 1 to 6.
8. The fluorescent nylon 12 according to claim 7, characterized in that, The fluorescent colors of the fluorescent nylon 12 include blue, green, and yellow.