Preparation method and application of MXD6-based organic phosphorescent material

Abstract

The application discloses a preparation method and application of MXD6-based organic phosphorescent material. The preparation method of the MXD6-based organic phosphorescent material comprises the following steps: mixing nylon MXD6 with an organic chromophore, and granulating; the method utilizes the rigid aromatic skeleton and hydrogen bond effect of the MXD6 to construct a limited microenvironment and a water and oxygen barrier, so that the material can realize fast response and long afterglow under the condition of no light activation, and good melt processing performance is maintained. The super-long organic phosphorescent material can further prepare a multi-color functional device through 3D printing, and is suitable for fields of information encryption, luminous textiles and high-precision display.

Description

Technical Field

[0001] The invention relates to the field of polymer-based ultralong organic phosphorescent material preparation technology, and in particular to a method for preparing and applying an MXD6-based organic phosphorescent material. Background Technology

[0002] Polymer-based ultralong organic phosphorescent (UOP) materials have shown great application potential in fields such as anti-counterfeiting, dynamic displays, information storage, smart sensing, and bioimaging, and have attracted widespread attention in recent years. Compared with small organic molecule systems, polymer materials possess superior mechanical flexibility, optical transparency, and environmental processability, enabling stable, tunable, and programmable luminescence functions, while also facilitating the large-scale fabrication of devices. Among the many methods for preparing polymer-based UOP materials, the direct doping strategy has become the most feasible technical route due to its simple process, good economy, and ease of industrial scale-up. This strategy typically involves doping organic chromophores as guest molecules into a rigid polymer matrix, restricting the movement of chromophore molecules through host-guest interactions, enhancing intersystem crossing processes, and constructing an oxygen diffusion barrier, thereby achieving long-afterglow luminescence. However, the polymer matrices used in existing technologies still have significant shortcomings. While some hydrophilic polymer matrices exhibit high rigidity and can effectively suppress oxygen diffusion in the absence of light, their poor moisture resistance makes them prone to absorbing moisture in humid environments. This leads to a decline in the material's mechanical properties and luminescent stability, severely limiting their application in outdoor environments or humid scenarios such as biomedicine. Others, such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polylactic acid (PLA), and polyamide 6 (PA6), while possessing good flexibility and processing properties, generally suffer from poor water and oxygen barrier properties. Furthermore, achieving effective afterglow emission often requires complex photoactivation processes, resulting in high energy consumption, cumbersome operation, and slow response kinetics, making it difficult to meet the demands of rapid response and high-precision applications.

[0003] Poly(m-xylenehexamethylene)diamide (MXD6), as a semi-aromatic polyamide, combines the good melt processability of aliphatic polyamides with the high strength and high barrier properties of fully aromatic polyamides. Its rigid aromatic backbone and interchain hydrogen bonds can form a confined microenvironment, effectively immobilizing organic chromophore molecules. Simultaneously, it possesses excellent gas barrier properties and water resistance, providing an ideal matrix choice for the preparation of fast-response ultralong organic phosphorescent materials. Furthermore, combining advanced manufacturing technologies such as fused deposition modeling (FDM) 3D printing with luminescent materials has become an important direction for promoting UOP materials from the laboratory to practical applications.

[0004] Therefore, developing polymer-based ultralong organic phosphorescent materials that combine rapid response characteristics and excellent water resistance and stability, especially constructing scalable multicolor ultralong organic phosphorescent systems using materials such as MXD6, is a technical challenge that urgently needs to be addressed in this field. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing polymer-based ultralong organic phosphorescent materials, such as poor water resistance or slow response kinetics, and to provide a fast-response ultralong organic phosphorescent material based on MXD6, its preparation method, and applications. This invention selects poly(m-xylenehexamethylene)diamide (MXD6), which possesses both a rigid aromatic framework and excellent gas barrier properties, as the polymer matrix. It then melt-blends MXD6 with polycyclic aromatic hydrocarbons or carbazole-based organic chromophores. The hydrogen bonds and rigid structure between MXD6 molecular chains form a confined microenvironment, effectively fixing the chromophore molecules, enhancing intersystem crossing, and suppressing non-radiative decay. Simultaneously, a dense water-oxygen barrier layer is constructed, enabling the material to achieve a rapid response without complex photoactivation. Furthermore, it can be processed into films, fibers, or devices through melt extrusion, spinning, casting, and 3D printing, showing promising prospects for industrial applications.

[0006] To achieve the above objectives, the present invention provides a method for preparing MXD6-based organic phosphorescent materials, comprising the following steps: The nylon MXD6 shown in formula (I) is mixed with an organic chromophore and granulated. Formula (I); In equation (I), the value of n ranges from 50 to 200; The organic chromophore is selected from at least one of the following structures: , , , , , , , , , , , , , .

[0007] According to the first aspect of the present invention, at least the following beneficial effects are achieved: Using poly(m-xylenehexamethylene)diamide (MXD6) as the polymer matrix, and melt-blending it with specific organic chromophores, two major core problems commonly found in existing polymer-based ultralong organic phosphorescent materials have been successfully solved. On the one hand, although traditional hydrophilic matrices (such as PVA and chitosan) can restrict molecular movement and block oxygen to a certain extent through their rigid structure, their strong water absorption causes the materials to easily swell and undergo phase separation in humid environments, exposing the chromophore molecules to water and oxygen, resulting in severe luminescence quenching and a decline in mechanical properties. In contrast, this invention utilizes the dense and confined microenvironment formed by the semi-aromatic rigid framework of MXD6 and numerous hydrogen bonds between the molecular chains to firmly fix the organic chromophore molecules within it, effectively suppressing the non-radiative decay of the triplet state. At the same time, the excellent gas barrier properties of MXD6 construct a stable water-oxygen barrier, enabling the material to maintain more than 90% of its afterglow quantum efficiency even after being immersed in water for 30 days, significantly improving the luminescence stability in humid and complex environments. On the other hand, existing polymer matrices often require energy-intensive and complex photoactivation processes to achieve effective afterglow, and their slow response kinetics make them unsuitable for rapid response applications. This invention, through the physical blending of MXD6 with chromophores, achieves rapid and sustained afterglow under UV excitation without additional photoactivation. This is because the rigid microenvironment of MXD6 promotes intersystem crossing of chromophores and reduces nonradiative transition rates. Furthermore, differential scanning calorimetry (DSC) analysis shows that the introduction of organic chromophores does not alter the melting point and crystallization behavior of MXD6; the material retains good melt processing properties, enabling large-scale fabrication of films, fibers, and complex devices through melt spinning, extrusion, and 3D printing, thus balancing high performance with the feasibility of industrial applications.

[0008] According to an embodiment of the present invention, the organic chromophore is selected from at least one of the following structures: , , , .

[0009] The aforementioned organic chromophores can form good interactions with the rigid aromatic skeleton of MXD6, and are more easily fixed in the confined microenvironment formed by the MXD6 molecular chain, thereby effectively promoting intersystem crossing and suppressing triplet nonradiative decay, which is beneficial to obtaining a longer afterglow lifetime.

[0010] According to an embodiment of the present invention, the mass ratio of the organic chromophore to the MXD6 is 0.01 to 5:100.

[0011] Under the above conditions, an effective balance is achieved between luminescence intensity and dispersion uniformity. When the doping concentration is too low, the number of chromophore molecules in the material is insufficient, resulting in weak luminescence; while when the doping concentration is too high, the chromophores tend to aggregate in the matrix, leading to a decrease in luminescence efficiency. This invention, by limiting the doping concentration within this reasonable range, ensures that a sufficient number of chromophores produce a bright and lasting afterglow, while avoiding aggregation and quenching caused by excessive concentration. This allows the material to maintain good luminescence performance while possessing good stability and practicality.

[0012] According to an embodiment of the present invention, the mass ratio of the organic chromophore to the MXD6 is 0.01 to 5:100. The mass ratio can be, for example, 0.01:100, 0.05:100, 0.1:100, 0.5:100, 1:100, 2:100, 3:100, 5:100, or any value between 0.01 and 5:100.

[0013] According to an embodiment of the present invention, the mixing is carried out by melt blending and granulation using a twin-screw extruder.

[0014] According to an embodiment of the present invention, the mixing is carried out in a twin-screw extruder, and the mixing temperature is 220–280°C.

[0015] According to an embodiment of the present invention, the screw speed of the twin-screw extruder is 150 to 500 r / min.

[0016] According to an embodiment of the present invention, the residence time for extrusion blending in the twin-screw extruder is 1 to 10 minutes.

[0017] This invention involves melt-blending MXD6 with organic chromophores under the aforementioned conditions. This process achieves uniform dispersion of the chromophores within the matrix without causing excessive thermal degradation of the material. The blends prepared under these conditions exhibit good compatibility and high uniformity, providing a stable raw material base for subsequent processing such as spinning, extrusion, and 3D printing. This facilitates the acquisition of ultralong organic phosphorescent materials with consistent performance.

[0018] According to an embodiment of the present invention, the mixing time is 1 to 10 minutes. The mixing time can be, for example, 1 minute, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 6 minutes, 8 minutes, 10 minutes, or any value between 1 and 10 minutes.

[0019] The present invention also provides the application of the preparation method of the MXD6-based organic phosphorescent material in MXD6-based organic phosphorescent devices.

[0020] According to an embodiment of the present invention, the method for preparing the MXD6-based organic phosphorescent device includes: processing the MXD6-based organic phosphorescent material to obtain an organic phosphorescent molded body with a predetermined shape; The processing method includes at least one of the following: twin-screw extruder processing, melt spinning machine processing, and casting machine processing.

[0021] According to an embodiment of the present invention, when the processing method is to process with a twin-screw extruder, the twin-screw extruder is a DHE-15 micro conical twin-screw extruder, the processing temperature is 220~280℃, and the screw speed is 2~30rpm.

[0022] According to an embodiment of the present invention, the processing temperature of the twin-screw extruder is 220~280°C. The processing temperature of the twin-screw extruder can be, for example, any value between 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, or 220~280°C.

[0023] According to an embodiment of the present invention, the screw speed of the twin-screw extruder is 2 to 30 rpm. The screw speed of the twin-screw extruder can be, for example, any value between 2 rpm, 5 rpm, 10 rpm, 15 rpm, 20 rpm, 25 rpm, 30 rpm, or 2 to 30 rpm.

[0024] Under the above conditions, the material can be fully plasticized and uniformly mixed, while avoiding performance degradation due to excessive temperature or shear. This results in 3D printing filaments with stable dimensions and good surface quality while retaining good light-emitting performance, which facilitates the subsequent fabrication of complex-shaped light-emitting devices through 3D printing.

[0025] According to an embodiment of the present invention, the processing method is to use a melt spinning machine with a spinning speed of 100~500 rpm and a torque of 10~50%.

[0026] According to an embodiment of the present invention, the spinning speed is 100~500 rpm. The spinning speed can be, for example, any value between 100 rpm, 150 rpm, 200 rpm, 250 rpm, 300 rpm, 400 rpm, 500 rpm, or 100~500 rpm.

[0027] According to an embodiment of the present invention, the torque is 10-50%. The torque can be, for example, any value between 10%, 15%, 20%, 25%, 30%, 40%, 50%, or 10-50%.

[0028] Under the above conditions, MXD6-based materials can smoothly pass through spinnerets in a molten state to form uniform fibers, while maintaining stable dispersion of chromophores and luminescence properties within the fibers. The resulting fibers can be directly used in textile processing to prepare luminescent textiles or flexible light-emitting devices, broadening the application of ultralong organic phosphorescent materials in wearable products.

[0029] According to an embodiment of the present invention, the processing method is to process the material in a casting machine with a screw speed of 20~50 r / min and a cold roller speed of 1~5 m / min.

[0030] According to an embodiment of the present invention, the predetermined form includes at least one of wire, filament, and film.

[0031] According to an embodiment of the present invention, when the predetermined shape is a wire, the method further includes obtaining an organic phosphorescent device by 3D printing the wire-shaped organic phosphorescent molded body.

[0032] According to an embodiment of the present invention, the 3D printing method includes fused deposition modeling; The equipment used was a Tuozhu ×1C 3D printer, with the following process parameters: layer height of 0.1~0.25mm, infill density of 10~20%, nozzle temperature of 240~280℃, and nozzle size of 0.2~1.0mm in diameter. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0034] Figure 1 The mechanical properties of the MXD6 sample and the resulting thin film prepared in Example 1 of this invention are shown in the diagram. Figure 2 The infrared spectra are those of Embodiments 1, 2, 3 and 4 of the present invention.

[0035] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0038] Example 1 This embodiment provides a method for fabricating a fast-response ultralong organic phosphorescent device based on MXD6, comprising the following steps: S1. The dried MXD6 and organic chromophore C were blended. The doping amount of organic chromophore C relative to MXD6 was 0.5%. The temperature of each zone of the twin-screw extruder was set to 240℃ (feeding section), 260℃ (compression section), 270℃ (metering section), and 280℃ (die head). The screw speed was 300 r / min, the feeding rate was about 8 kg / h, and the material residence time was about 2 min. The extrudate was water-cooled and pelletized to obtain C@MXD6 blend. S2. After drying, the blend is placed in a casting machine for processing. The screw speed is 50 r / min and the cold roller speed is 5 m / min, thus obtaining the transparent C@MXD6 film of this embodiment. Organic chromophore C.

[0039] Example 2 The difference between this embodiment and Embodiment 1 is that the organic chromophore crown ene C in step S1 is changed to D, while the remaining steps are the same as in Embodiment 1, thus obtaining the D@MXD6 film of this embodiment.

[0040] Organic chromophore D.

[0041] The D@MXD6 film prepared in this embodiment was immersed in water for different times to test the afterglow lifetime. After immersion in water for 30 consecutive days, the film still maintained an afterglow efficiency of more than 90%, which proves that MXD6-based ultralong organic phosphorescent materials have great application potential in harsh and humid environments.

[0042] Example 3 The difference between this embodiment and Embodiment 1 is that the organic chromophore crown ene C in step S1 is changed to T, while the remaining steps are the same as in Embodiment 1, thus obtaining the T@MXD6 film of this embodiment.

[0043] Organic chromophore T.

[0044] Example 4 The difference between this embodiment and Example 1 is that the organic chromophore C compound in step 1) is changed to B, while the remaining steps are the same as in Example 1, thus obtaining the B@MXD6 film of this embodiment.

[0045] Organic chromophore B.

[0046] Example 5 Example 5 differs from Example 1 in that step S2 is adjusted so that the blend is passed through a melt spinning machine to obtain filaments. After drying, the C@MXD6 blend is passed through a melt spinning machine at 245°C to obtain filaments, which are then designed as school badges and sewn into the clothing pattern.

[0047] Example 6 Example 6 differs from Example 2 in that step S2 is adjusted so that the blend is passed through a melt spinning machine to obtain filaments. The D@MXD6 blend is dried and then passed through a melt spinning machine at 245°C to obtain filaments, which are then designed as school badges and sewn into the clothing pattern.

[0048] Example 7 Example 7 differs from Example 3 in that step S2 is adjusted so that the blend is passed through a melt spinning machine to obtain filaments. The T@MXD6 blend is dried and then passed through a melt spinning machine at 245°C to obtain filaments, which are then designed as school badges and sewn into the clothing pattern.

[0049] Example 8 Example 8 differs from Example 4 in that step S2 is adjusted so that the blend is passed through a melt spinning machine to obtain filaments. After drying, the B@MXD6 blend is passed through a melt spinning machine at 245°C to obtain filaments, which are then designed as school badges and sewn into the clothing pattern.

[0050] Example 9 The difference between this embodiment and Embodiment 1 is that step S2 is adjusted so that the blend is processed through a micro conical twin-screw extruder to obtain 3D printed filament, and then multi-color ultra-long organic phosphorescent devices are obtained through 3D printing technology. Specifically: After drying, the C@MXD6 blend was processed in a DHE-15 micro conical twin-screw extruder at a processing temperature of 260°C and a screw speed of 30 rpm to obtain the C@MXD6 3D printing filament of this embodiment. The obtained 3D printed filament is used to fabricate a fast-response multicolor ultra-long organic phosphorescent device using fused deposition modeling (FDM) technology. The equipment used is a Topzhu ×1C 3D printer. The previously prepared STL file is imported into the slicing software BambuStudio with the following parameters: layer height 0.2mm, infill density 15%, nozzle temperature 270℃, and nozzle size 1.0mm in diameter, thus obtaining the multicolor ultra-long organic phosphorescent device of this embodiment.

[0051] Example 10 The difference between this embodiment and Embodiment 2 is that step S2 is adjusted so that the blend is processed through a micro conical twin-screw extruder to obtain 3D printed filament, and then multi-color ultra-long organic phosphorescent devices are obtained through 3D printing technology. Specifically: After drying, the D@MXD6 blend was processed in a DHE-15 micro conical twin-screw extruder at a processing temperature of 260°C and a screw speed of 30 rpm to obtain the 3D printing filament of D@MXD6 in this embodiment. The obtained 3D printed filament is used to fabricate a fast-response multicolor ultra-long organic phosphorescent device using fused deposition modeling (FDM) technology. The equipment used is a Topzhu ×1C 3D printer. The previously prepared STL file is imported into the slicing software BambuStudio with the following parameters: layer height 0.2mm, infill density 15%, nozzle temperature 270℃, and nozzle size 1.0mm in diameter, thus obtaining the multicolor ultra-long organic phosphorescent device of this embodiment.

[0052] Example 11 The difference between this embodiment and Embodiment 3 is that step S2 is adjusted so that the blend is processed through a micro conical twin-screw extruder to obtain 3D printed filament, and then multi-color ultra-long organic phosphorescent devices are obtained through 3D printing technology. Specifically: After drying, the T@MXD6 blend was processed in a DHE-15 micro conical twin-screw extruder at a processing temperature of 260°C and a screw speed of 30 rpm to obtain the T@MXD6 3D printing filament of this embodiment. The obtained 3D printed filament is used to fabricate a fast-response multicolor ultra-long organic phosphorescent device using fused deposition modeling (FDM) technology. The equipment used is a Topzhu ×1C 3D printer. The previously prepared STL file is imported into the slicing software BambuStudio with the following parameters: layer height 0.2mm, infill density 15%, nozzle temperature 270℃, and nozzle size 1.0mm in diameter, thus obtaining the multicolor ultra-long organic phosphorescent device of this embodiment.

[0053] Example 12 The difference between this embodiment and Embodiment 4 is that step S2 is adjusted so that the blend is processed through a micro conical twin-screw extruder to obtain 3D printed filament, and then multi-color ultra-long organic phosphorescent devices are obtained through 3D printing technology. Specifically: After drying, the B@MXD6 blend was processed in a DHE-15 micro conical twin-screw extruder at a processing temperature of 260°C and a screw speed of 30 rpm to obtain the 3D printing filament of B@MXD6 in this embodiment. The obtained 3D printed filament is used to fabricate a fast-response multicolor ultra-long organic phosphorescent device using fused deposition modeling (FDM) technology. The equipment used is a Topzhu ×1C 3D printer. The previously prepared STL file is imported into the slicing software BambuStudio with the following parameters: layer height 0.2mm, infill density 15%, nozzle temperature 270℃, and nozzle size 1.0mm in diameter, thus obtaining the multicolor ultra-long organic phosphorescent device of this embodiment.

[0054] The blends of C@MXD6, D@MXD6, T@MXD6, and B@MXD6 from Examples 5-8 were melt-spun into continuous filaments, which were then embroidered into a school emblem pattern and sewn onto fabric. After the excitation light source was turned off, the embroidered pattern exhibited clearly visible colored afterglow, demonstrating that the MXD6-based ultralong organic phosphorescent material can withstand the high-temperature shearing process of melt spinning while maintaining good luminescent performance, making it suitable for use in luminescent textiles and flexible wearable devices.

[0055] Examples 9-12 further describe how the four blends described above were fabricated into 3D printing filaments using a micro twin-screw extruder, and multicolor devices with complex patterns were printed using fused deposition modeling (FDM). The printed devices, even after UV excitation and when the light source was turned off, exhibited a bright and long-lasting colored afterglow, with different chromophores contributing a rich variety of luminescent colors. This demonstrates that MXD6-based ultralong organic phosphorescent materials not only possess excellent melt processing properties and 3D printing adaptability, but also enable rapid customization of multicolor luminescent devices through simple filament replacement, providing a feasible technical path for the large-scale fabrication of information encryption, anti-counterfeiting labels, and personalized luminescent devices.

[0056] Example 13 This embodiment is used to investigate the effect of the doping amount of different organic chromophores relative to MXD6 on the luminescence performance of the prepared material. The difference from Example 1 is that the doping amount of C relative to MXD6 in step S1 is adjusted to 0.01wt%, and the remaining steps are the same as in Example 1. Luminescent materials with different C doping amounts are obtained in this embodiment, and the luminescence performance is measured. The results are shown in Table 2.

[0057] Example 14 This embodiment is used to investigate the effect of the doping amount of different organic chromophores relative to MXD6 on the luminescence performance of the prepared material. The difference from Example 1 is that the doping amount of C relative to MXD6 in step S1 is adjusted to 0.05wt%, and the remaining steps are the same as in Example 1. Luminescent materials with different C doping amounts are obtained in this embodiment, and the luminescence performance is measured. The results are shown in Table 2.

[0058] Example 15 This embodiment is used to investigate the effect of the doping amount of different organic chromophores relative to MXD6 on the luminescence performance of the prepared material. The difference from Example 1 is that the doping amount of C relative to MXD6 in step S1 is adjusted to 0.1wt%, and the remaining steps are the same as in Example 1. Luminescent materials with different C doping amounts are obtained in this embodiment, and the luminescence performance is measured. The results are shown in Table 2.

[0059] Example 16 This embodiment is used to investigate the effect of the doping amount of different organic chromophores relative to MXD6 on the luminescence performance of the prepared material. The difference from Example 1 is that the doping amount of C relative to MXD6 in step S1 is adjusted to 1wt%, and the remaining steps are the same as in Example 1. Luminescent materials with different C doping amounts are obtained in this embodiment, and the luminescence performance is measured. The results are shown in Table 2.

[0060] Example 17 This embodiment is used to investigate the effect of the doping amount of different organic chromophores relative to MXD6 on the luminescence performance of the prepared material. The difference from Example 1 is that the doping amount of C relative to MXD6 in step S1 is adjusted to 2wt%, and the remaining steps are the same as in Example 1. Luminescent materials with different C doping amounts are obtained in this embodiment, and the luminescence performance is measured. The results are shown in Table 2.

[0061] Test example: Figure 1 Referring to the mechanical property diagrams of the MXD6 material prepared according to ISO 527-3-2018 and the thin film prepared in Example 1, it can be seen that the mechanical properties of the MXD6-based ultralong organic phosphorescent thin film prepared in Example 1 are comparable, indicating that the preparation of MXD6-based ultralong organic phosphorescent materials is not affected by organic chromophore doping.

[0062] Figure 2 The infrared spectra of MXD6 and Examples 1, 2, 3 and 4 show that the characteristic absorption peak of the benzene ring appeared after doping with the organic chromophore, and the structure of MXD6 itself was not affected.

[0063] Comparison of curves obtained by differential scanning calorimetry: The differential scanning calorimetry (DSC) curves of the four doped samples prepared in Examples 1 to 4 largely overlapped with those of pure MXD6, with no significant changes in the onset temperature, peak temperature, and peak shape of the melting endothermic peak. This indicates that the introduction of a small amount of organic chromophores did not disrupt the crystalline structure and thermal transition behavior of MXD6, and the material maintained a melting point and processing temperature window similar to that of pure MXD6. These results demonstrate good compatibility between the organic chromophores and the MXD6 matrix, and the doping process did not adversely affect the polymer's thermal processing properties. This ensures the smooth execution of subsequent processing techniques such as twin-screw extrusion, melt spinning, and 3D printing, demonstrating industrial processing feasibility comparable to that of pure MXD6.

[0064] Afterglow emission performance of C@MXD6 and D@MXD6 in dry state and after immersion in water: The C@MXD6 film prepared in Example 1 exhibited a bright and persistent yellow afterglow when the light source was turned off after UV excitation, with both its luminescence intensity and duration being significantly better than the D@MXD6 film prepared in Example 2. This indicates that there is a stronger interaction between the chromophore C and the MXD6 matrix, which can more effectively restrict molecular motion, enhance intersystem crossing, and reduce non-radiative decay, thereby obtaining superior ultralong organic phosphorescence performance.

[0065] After immersing the aforementioned films in water, afterglow tests were conducted again. The results showed that neither group of samples exhibited significant attenuation in luminescence brightness or duration, with C@MXD6 maintaining a clear advantage over D@MXD6. This indicates that the rigid aromatic skeleton of MXD6 and the dense structure formed by interchain hydrogen bonds effectively block the intrusion of water molecules and oxygen, stably fixing the organic chromophore molecules within a confined microenvironment. This significantly enhances the luminescence stability of the material under humid conditions, laying the foundation for its application in complex real-world environments.

[0066] The long afterglow capability of the films prepared in Examples 1-4: The long afterglow capability of the films prepared in Examples 1-4 was compared, and the results are shown in Table 1. The test conditions were: 10W UV lamp for 3 seconds, room temperature and dark environment.

[0067] Table 1. Long afterglow capability of thin films As can be seen from Table 1, the choice of luminescent compound C has a significant advantage over other types of organic chromophores. C is a fused-ring aromatic hydrocarbon consisting of six benzene rings linked in a six-membered ring. Its molecular structure, compared to the planar and rigid chemical structures of other luminescent compounds in the table, is more conducive to suppressing intramolecular motion when combined with MXD6, thereby reducing nonradiative decay channels and better suppressing the nonradiative transition of the molecule from the triplet excited state to the ground state, thus exhibiting a longer afterglow effect.

[0068] Table 2. Effect of C doping amount on the ultralong organic phosphorescence properties of the material As can be seen from Table 2, when the C doping concentration is too low, the number of organic molecules that absorb light and generate excitons is too small. Even if each exciton has a long lifetime, the overall luminescence intensity will be very weak. On the other hand, excessively high doping concentration can easily lead to the aggregation of organic long-afterglow molecules in the polymer matrix, resulting in a decrease in afterglow brightness.

[0069] In summary, this invention upgrades and regenerates MXD6 into a persistent luminescent polymer element by melt-doping organic chromophores into MXD6. The rigid aromatic backbone of MXD6 is stabilized by interchain hydrogen bonds, forming a confined microenvironment that can fix the luminescent host while enhancing mechanical strength and oxygen barrier properties. The full-color 3D-printed ultralong phosphorescent device of this invention features an easily scalable, cost-effective fabrication process with excellent industrial application prospects and significant value in fields such as customized devices and information encryption.

[0070] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing an MXD6-based organic phosphorescent material, characterized in that, Includes the following steps: The nylon MXD6 shown in formula (I) is mixed with an organic chromophore and granulated. Formula (I); In equation (I), the value of n ranges from 50 to 200; The organic chromophore is selected from at least one of the following structures: 、 、 、 ； The mass ratio of the organic chromophore to the nylon MXD6 is 0.01 to 5:

100.

2. The method for preparing MXD6-based organic phosphorescent materials according to claim 1, characterized in that, The mixing is carried out in a twin-screw extruder at a temperature of 220–280°C.

3. The method for preparing MXD6-based organic phosphorescent materials according to claim 1, characterized in that, The mixing time is 1 to 10 minutes.

4. The application of the material prepared by the method of any one of claims 1 to 3 in MXD6-based organic phosphorescent devices.

5. The application according to claim 4, characterized in that, The method for preparing the MXD6-based organic phosphorescent device includes: processing the MXD6-based organic phosphorescent material to obtain an organic phosphorescent molded body with a predetermined shape; The processing method includes at least one of the following: twin-screw extruder processing, melt spinning machine processing, and casting machine processing.

6. The application according to claim 5, characterized in that, The predetermined form includes at least one of wire, filament, and film.

7. The application according to claim 6, characterized in that, When the predetermined shape is a wire, it also includes obtaining an organic phosphorescent device by 3D printing the wire-shaped organic phosphorescent molded body.

8. The application of the MXD6-based organic phosphorescent material prepared by the method described in any one of claims 1 to 3 in information security, luminescent textiles, energy-saving displays and high-resolution 3D printing.

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