Preparation and application of fluorescent polymer and highly elastic flexible fluorescent composite fiber

Abstract

The present invention belongs to the technical field of fluorescent polymer materials, and more specifically, relates to a fluorescent polymer, a preparation of a highly elastic flexible fluorescent composite fiber and its application. The method uses two diamine monomers and a dianhydride monomer as raw materials, and synthesizes a fluorescent polymer by a one-step polycondensation method. The fluorescent polymer is prepared by an electrostatic spinning method to obtain an electrostatically spun membrane, and then a thermoplastic polymer fiber is used as an inner core, and the electrostatically spun membrane is coated on the surface of the thermoplastic polymer fiber by a spray-press coating method to prepare a highly elastic flexible fluorescent composite fiber.

Description

Technical Field

[0001] The present invention belongs to the technical field of fluorescent polymer materials, and more specifically, relates to a fluorescent polymer, a preparation method of a highly elastic and flexible fluorescent composite fiber, and applications thereof. Background Art

[0002] Organic fluorescent materials have good solution processability and relatively low cost. Their chromophores are evenly distributed, stable in content, and have good luminescence performance. However, most traditional organic fluorophores will cause fluorescence quenching when aggregated, which is not conducive to processing into solid-state devices. Therefore, a method is needed to avoid fluorescence quenching caused by molecular aggregation of fluorescent materials as much as possible.

[0003] Among fluorescent materials, fluorescent polymers have the advantages of light weight, high stretchability and good biocompatibility, and have great potential in future applications. Therefore, enhancing the stretchability of flexible fluorescent fibers is an important aspect to further improve the performance of luminescent fibers and expand their application. Summary of the invention

[0004] The purpose of the present invention is to provide a fluorescent polymer, a flexible fluorescent fiber and a preparation method and application thereof in view of the above shortcomings. The fluorescent polymer has good solubility and emits orange-yellow light under ultraviolet light. The fluorescent fiber prepared with the fluorescent polymer also has good luminescence performance.

[0005] To achieve the above object, the present invention is implemented by the following technical solutions:

[0006] A fluorescent polymer, with a weight average molecular weight of 105,000-136,000 (a polymer with this molecular weight is beneficial to the subsequent fiber molding process), and the structural formula of the fluorescent polymer is:

[0007]

[0008] The synthetic route of the above fluorescent polymer is as follows:

[0009]

[0010] Furthermore, the preparation method of the fluorescent polymer comprises the following steps:

[0011] Under nitrogen protection, two diamine monomers and ketone anhydride monomers are mixed into an organic solvent and stirred at room temperature for 0.5 to 1 hour, which is beneficial to the full dissolution of the monomers and ensures full contact and reaction;

[0012] Add the catalyst, raise the temperature to 195°C, and continue the reaction for 6 to 10 hours;

[0013] After the reaction is completed, the reaction solution is poured into 300-500 mL of anhydrous ethanol, filtered after sedimentation, and washed with deionized water to obtain the target polymer; the obtained polymer is vacuum dried at 100-150° C. for 10-15 h to ensure that the sample is completely dry.

[0014] Preferably, the molar ratio of the tetramethyldiamine monomer:2,6-dimethylaniline:ketoanhydride monomer is 2:8:10.

[0015] In order to obtain a high molecular weight polymer that meets the fiber preparation and spinnability requirements, preferably, the amount of the organic solvent is 4 to 10 times the total mass of the diamine monomer and the ketone anhydride monomer, and the amount of the catalyst is 1% to 4% of the mass of the organic solvent.

[0016] Preferably, the organic solvent is m-cresol; and the catalyst is isoquinoline.

[0017] A fluorescent composite fiber comprises a thermoplastic polymer fiber and an electrospun fiber membrane wrapped on the surface of the thermoplastic polymer fiber. The preparation of the electrospun fiber membrane comprises the following steps: dissolving the fluorescent polymer in an organic solvent to prepare an electrospinning solution, and obtaining the electrospun fiber membrane through an electrospinning method.

[0018] Preferably, the organic solvent is a mixture of two organic solvents, one of which is N,N-dimethylformamide.

[0019] One of methylformamide, N,N-dimethylacetamide, and tetrahydrofuran, and the other solvent is one of ethanol, acetone, dichloromethane, and chloroform, wherein the volume ratio of one solvent to the other solvent is 9:1 to 7:3;

[0020] And / or, the electrospinning solution concentration is 15wt% to 25wt%; and / or, the electrospinning process parameters are: spinning voltage 12 to 15 kV, receiving distance 15 to 25 cm, spinning solution 1 to 5 mL, nozzle aperture 0.5 to 1 mm, spinning solution propulsion speed 1 to 5 mL / h, room temperature, relative humidity 25% to 50%.

[0021] More preferably, the organic solvent is a mixed solvent of N,N-dimethylacetamide and ethanol in a volume ratio of 9:1;

[0022] And / or, the electrospinning solution concentration is 18 wt %.

[0023] And / or, the electrospinning process parameters are: spinning voltage 12 kV, receiving distance 20 cm, spinning solution 2 mL, nozzle aperture 0.5 mm, spinning solution advancing speed 1.5 mL / h, room temperature, relative humidity 35%.

[0024] The method for preparing the above-mentioned flexible fluorescent composite fiber comprises the following steps:

[0025] The electrospun fiber membrane is cut into uniform sizes, a thermoplastic polymer fiber is used as the inner core, a layer of adhesive is sprayed on the surface of the thermoplastic polymer fiber by spraying and pressing, and then the cut electrospun fiber is rolled on the surface of the thermoplastic polymer fiber to prepare a fluorescent composite fiber. The present invention adopts the spraying and pressing rolling method to prepare the composite fiber, which overcomes the technical problem that the electrospun fiber filaments are too thin and will fall off and float.

[0026] Preferably, the electrospun fiber membrane is cut to a size of 20×2 cm.

[0027] Preferably, the adhesive is one of water-based polyacrylate, polyvinyl alcohol, and silicone adhesive; the viscosity of the adhesive is between 300 and 10,000 cps, and more preferably the adhesive is polyvinyl alcohol.

[0028] Preferably, the spraying method uses a nozzle with an inner diameter of 0.4 mm, a spraying distance of 10 cm, a spraying speed of 5 ml / min, and a spraying time of 1 min.

[0029] Preferably, the diameter of the thermoplastic polyurethane fiber is one of 0.4 to 1 mm, the diameter of the fiber in the electrospun fiber membrane is 0.5 to 2 μm, and the thickness of the coating layer is 100 to 120 μm.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The present invention provides a new fluorescent polymer and a preparation method thereof, which uses two diamine monomers and ketone anhydride monomers for copolymerization, thereby increasing the molecular weight of the polymer, promoting the spinnability of the polymer when preparing fibers, and expanding the application range of the polymer in processing solid-state devices. The introduced tetramethyldiamine monomer can increase the steric hindrance of the polymer structure and avoid fluorescence quenching caused by pyrene aggregation in the fluorescent polymer in the solid state.

[0032] (2) The method for preparing the flexible fluorescent composite fiber of the present invention is simple to operate and can effectively control the thickness of the composite fiber coating layer by adjusting the size of the electrospun fiber membrane.

[0033] (3) The flexible fluorescent composite fiber described in the present invention has good stretchability and bending resistance, and has bright orange-yellow fluorescence under ultraviolet light. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The H-NMR spectrum of the fluorescent polymer prepared in Example 1;

[0035] Figure 2This is a SEM image of the composite fiber prepared in Example 2;

[0036] Figure 3 This is the stress-strain diagram of the fluorescent composite fiber prepared in Example 3;

[0037] Figure 4 This is a comparison chart of the daily light irradiation and ultraviolet light irradiation of the fluorescent composite fiber under the complex weaving process described in 4. DETAILED DESCRIPTION

[0038] The preferred embodiments of the present invention will be described in more detail below in conjunction with the accompanying drawings and specific examples.

[0039] The tetramethyldiamine monomer used in the following examples was prepared with reference to patent 202011492069.2.

[0040] 2,6-Dimethylaniline and ketone anhydride monomers were commercially available from TCI.

[0041] Example 1

[0042] This embodiment provides a fluorescent polymer, the structural formula of which is as follows:

[0043]

[0044] The synthetic route is as follows:

[0045]

[0046] The preparation method thereof comprises the following steps:

[0047] (1) Under nitrogen protection, add 2 mmol of tetramethyldiamine monomer, 8 mmol of 2,6-diaminotoluene and 10 mmol of ketone anhydride monomer into m-cresol and stir at room temperature for 0.5 h;

[0048] (2) adding isoquinoline as a catalyst, raising the temperature to 195°C, and continuing the reaction for 8 hours;

[0049] (3) After the reaction is completed, the reaction solution is poured into 400 mL of anhydrous ethanol, filtered after sedimentation, and washed with deionized water to obtain the target polymer; the obtained polymer is vacuum dried at 120° C. for 12 h to ensure that the sample is completely dry.

[0050] Figure 1 This is the H-NMR spectrum of the prepared fluorescent polymer. It can be observed that the integral values ​​of the absorption peaks of the synthesized polymer are completely consistent with the number of protons in the designed structural formula, indicating that the target polymer has been successfully synthesized and its fluorescence quantum yield reaches 24%.

[0051] Example 2

[0052] This embodiment provides a preparation method of an electrospun fiber membrane, and the preparation method is as follows:

[0053] 1.0284 g of the fluorescent polymer described in Example 1 was weighed and mixed with 5 mL of N,N-dimethylacetamide, and shaken until the polymer was fully dissolved to prepare an 18 wt% fluorescent polymer solution. At room temperature and relative humidity of 25%, the electrospinning voltage was set to 12 kV, the receiving distance was 20 cm, 2 mL of spinning solution was absorbed, the nozzle aperture was 0.5 mm, the spinning solution propulsion speed was 1.5 mL / h, and aluminum foil was used for receiving to obtain an electrospun fiber membrane.

[0054] Example 3

[0055] This embodiment provides a preparation method of a flexible fluorescent composite fiber, and the preparation method is as follows:

[0056] The fiber membrane prepared in Example 2 was cut into a uniform size of 20×2 cm, with thermoplastic polyurethane fiber as the inner core, a layer of polyvinyl alcohol was coated on the surface as an adhesive, and then the cut electrospun fiber was rolled on the surface of the thermoplastic polyurethane fiber to prepare pyrene-containing polyimide / thermoplastic polyurethane composite fiber.

[0057] like Figure 2 As shown, the prepared composite fiber is evenly coated, the average diameter of the electrospun fiber on the surface is about 500nm, the thickness is uniform and there is almost no beading. Figure 3 It can be seen that the prepared flexible fluorescent composite fiber has an elongation at break of 150.83% and a breaking stress of 25.51 MPa, and has very good tensile properties.

[0058] Example 4

[0059] This embodiment provides an application of the flexible fluorescent composite fiber described in Embodiment 3.

[0060] like Figure 4 The figure shows the comparison of the curled state of the flexible fluorescent fiber and the fluorescent braided rope under daily light and ultraviolet light. It can be observed that under ultraviolet light, the curled fluorescent composite fiber and the fluorescent braided rope still have orange-yellow fluorescence. In this embodiment, the flexible fluorescent composite fiber is woven and applied to fabric anti-counterfeiting.

[0061] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Without departing from the scope and technical principles of the described embodiments, many modifications and changes are obvious to those of ordinary skill in the art, and these modifications and changes should also be regarded as the scope of protection of the present invention.

Claims

1. A fluorescent polymer, characterized in that: The weight average molecular weight is 105,000-136,000, and the structural formula of the fluorescent polymer is: 。 2. The method for preparing a fluorescent polymer according to claim 1, wherein: The synthetic route is as follows: 。 3. The method for preparing a fluorescent polymer according to claim 2, characterized in that: The method comprises the following steps: under nitrogen protection, tetramethyldiamine monomer, 2,6-diaminotoluene and ketone anhydride monomer are mixed into an organic solvent, and catalytic stirring reaction is carried out at room temperature for 0.5 to 1 hour, the catalyst is isoquinoline, the amount of the organic solvent is 4 to 10 times the total mass of the diamine monomer and the ketone anhydride monomer, and the amount of the catalyst is 1% to 4% of the mass of the organic solvent.

4. The method for preparing a fluorescent polymer according to claim 3, characterized in that: The organic solvent is m-cresol.

5. A highly elastic flexible fluorescent composite fiber, characterized in that: It comprises thermoplastic polymer fibers and an electrospun fiber membrane wrapped on the surface of the thermoplastic polymer fibers; the preparation of the electrospun fiber membrane comprises the following steps: dissolving the fluorescent polymer described in claim 1 in an organic solvent to prepare an electrospinning solution, and obtaining the electrospun fiber membrane by an electrospinning method; the thermoplastic polymer fiber is any one of styrene-based thermoplastic elastomer fibers, thermoplastic polyurethane fibers, thermoplastic polyolefin elastic fibers, and thermoplastic polyester elastic fibers.

6. The highly elastic flexible fluorescent composite fiber according to claim 5, characterized in that: The organic solvent is a mixture of two organic solvents, one of which is N,N-dimethylformamide, N,N-dimethylacetamide, and tetrahydrofuran, and the other is ethanol, acetone, dichloromethane, and chloroform, wherein the volume ratio of one solvent to the other is 9:1 to 7:3; And / or, the electrospinning solution concentration is 15 wt%~25 wt%; and / or, the electrospinning process parameters are: spinning voltage 12~15 kV, receiving distance 15~25 cm, spinning solution 1~5 mL, nozzle aperture 0.5~1 mm, spinning solution propulsion speed 1~5mL / h, room temperature, relative humidity 25%~50%.

7. The high elasticity flexible fluorescent composite fiber according to claim 5, characterized in that: The organic solvent is a mixed solvent of N ,N-dimethylacetamide and ethanol, with a volume ratio of 9:1; and / or, the electrospinning solution concentration is 18wt%; And / or, the electrospinning process parameters are: spinning voltage 12 kV, receiving distance 20 cm, spinning solution 2 mL, nozzle aperture 0.5 mm, spinning solution advancing speed 1.5 mL / h, room temperature, relative humidity 35%.

8. The method for preparing a highly elastic and flexible fluorescent composite fiber according to any one of claims 5 to 7, characterized in that: The following steps are involved: The electrospun fiber membrane is cut into uniform sizes, and the thermoplastic polymer fiber is used as the inner core. A layer of adhesive is sprayed on the surface of the thermoplastic polymer fiber by spraying and pressing, and then the cut electrospun fiber is rolled on the surface of the thermoplastic polymer fiber to prepare a highly elastic and flexible fluorescent composite fiber.

9. The method for preparing the highly elastic flexible fluorescent composite fiber according to claim 8, characterized in that: The adhesive is any one of water-based polyacrylate, polyvinyl alcohol, and organic silicone adhesive; the viscosity of the adhesive is between 300 and 10,000 cps; And / or, the spraying method adopts a nozzle with an inner diameter of 0.4-1 mm, a spraying distance of 5-20 cm, a spraying speed of 5-10 ml / min, and a spraying time of 0.5-1.5 min; And / or, the diameter of the thermoplastic polymer fiber is 0.4-1 mm, the diameter of the high elasticity flexible fluorescent composite fiber is 0.5-2 μm, and the thickness of the coating layer is 50-120 μm.

10. The method for preparing the highly elastic flexible fluorescent composite fiber according to claim 8, characterized in that: The spraying method adopts a nozzle with an inner diameter of 0.4 mm, a spraying distance of 10 cm, a spraying speed of 5 ml / min, a spraying time of 1 min, and polyvinyl alcohol as the adhesive.

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