Shape memory fluorescent polyurethane resin as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of shape memory materials, and particularly relates to shape memory fluorescent polyurethane resin as well as a preparation method and application thereof. The preparation method comprises the following steps: mixing polyethylene glycol, hexamethylene diisocyanate, an organic tin catalyst and an organic solvent to carry out nucleophilic addition reaction, mixing an obtained polyurethane prepolymer reaction solution with 5, 5 '-diamino-2, 2'-dipyridyl to carry out addition reaction, mixing an obtained addition reaction solution with europium salt to carry out coordination reaction, and carrying out vacuum drying to obtain the europium-doped polyurethane composite material. A coordination reaction solution is obtained; and finally, removing the solvent from the coordination reaction solution to obtain the shape memory fluorescent polyurethane resin. The shape memory fluorescent polyurethane resin provided by the invention can show strong fluorescent response under the action of external stimulation, has higher fluorescence intensity and light stability, has excellent mechanical properties (including tensile strength, elongation at break and toughness), and has wide application prospects in the fields of intelligent sensing, medical diagnosis, environmental monitoring and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of shape memory materials, and in particular relates to a shape memory fluorescent polyurethane resin and a preparation method and application thereof. Background Art

[0002] Shape memory materials are smart materials that can return to a predetermined shape under external stimuli. In recent years, they have received extensive attention and application in aerospace, smart textiles, medical devices and other fields. Shape memory polymers (SMPs), as a type of shape memory material, have become a hot topic of research due to their excellent mechanical properties, processability and good shape memory effect. Polyurethane (PU) resin has become one of the important representatives of shape memory polymers due to its good mechanical properties, thermal stability and adjustability.

[0003] At the same time, with the widespread application of fluorescent materials in display technology, sensors, optoelectronic devices and other fields, fluorescent PU resin has gradually become a new research direction. Fluorescent materials have the functions of energy conversion and information transmission, and have important application potential in intelligent perception, medical diagnosis and other aspects. Therefore, combining the shape memory effect with the fluorescent properties, developing PU resins with both shape memory function and fluorescent properties will be able to provide multifunctional solutions in a wider range of fields.

[0004] However, the existing shape memory PU resins are relatively lacking in fluorescence intensity and stability, which limits their application in practical applications, especially in the fields of optical sensing and self-diagnosis. Summary of the invention

[0005] The object of the present invention is to provide a shape memory fluorescent polyurethane resin and a preparation method and application thereof. The shape memory fluorescent polyurethane resin provided by the present invention can exhibit a strong fluorescence response under external stimulation, has high fluorescence intensity and photostability, and has excellent mechanical properties (including tensile strength, elongation at break and toughness). It has broad application prospects in the fields of intelligent sensing, medical diagnosis and environmental monitoring.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing a shape memory fluorescent polyurethane resin, comprising the following steps:

[0008] (1) mixing polyethylene glycol, hexamethylene diisocyanate, an organic tin catalyst and an organic solvent to carry out a nucleophilic addition reaction to obtain a polyurethane prepolymer reaction solution;

[0009] (2) mixing the polyurethane prepolymer reaction solution and 5,5′-diamino-2,2′-bipyridine to carry out an addition reaction to obtain an addition reaction solution;

[0010] (3) mixing the addition reaction solution and the europium salt to carry out a coordination reaction to obtain a coordination reaction solution;

[0011] (4) removing the solvent from the coordination reaction solution to obtain the shape memory fluorescent polyurethane resin.

[0012] Preferably, the number average molecular weight of the polyethylene glycol is 5000-8000.

[0013] Preferably, the ratio of the mass of the polyethylene glycol to the volume of the hexamethylene diisocyanate is 16-20 g:1 mL.

[0014] Preferably, in step (1), the temperature of the nucleophilic addition reaction is 60 to 80° C. and the time is 1 to 3 hours.

[0015] Preferably, the mass ratio of the polyethylene glycol to the 5,5′-diamino-2,2′-bipyridine is 30 to 35:1.

[0016] Preferably, in step (2), the temperature of the addition reaction is 60 to 80° C. and the time is 15 to 18 hours.

[0017] Preferably, the europium salt comprises europium chloride.

[0018] Preferably, the mass ratio of the 5,5′-diamino-2,2′-bipyridine to the europium salt is 2 to 8.5:1;

[0019] The temperature of the coordination reaction is 60-80° C. and the time is 20-30 minutes.

[0020] The present invention provides a shape memory fluorescent polyurethane resin prepared by the preparation method described in the above technical scheme.

[0021] The present invention provides the use of the shape memory fluorescent polyurethane resin described in the above technical solution in shape memory devices, intelligent sensing, optical sensing or the preparation of medical diagnostic materials.

[0022] The present invention provides a method for preparing a shape memory fluorescent polyurethane resin, comprising the following steps:

[0023] (1) polyethylene glycol, hexamethylene diisocyanate, an organic tin catalyst and an organic solvent are mixed to carry out a nucleophilic addition reaction to obtain a polyurethane prepolymer reaction solution; (2) the polyurethane prepolymer reaction solution and 5,5′-diamino-2,2′-bipyridine are mixed to carry out an addition reaction to obtain an addition reaction solution; (3) the addition reaction solution and europium salt are mixed to carry out a coordination reaction to obtain a coordination reaction solution; (4) the coordination reaction solution is desolventized to obtain the shape memory fluorescent polyurethane resin. The present invention adopts a prepolymer method, and by reasonably selecting the type of synthetic monomer, the molecular structure of the polyurethane resin can be optimized, thereby overcoming the inherent contradiction between the tensile strength, elongation at break and toughness of the polyurethane resin material. The obtained shape memory fluorescent polyurethane resin material has high tensile strength, good elongation at break and excellent toughness, and can have good ductility and energy absorption capacity while ensuring material strength; thus, the shape memory fluorescent polyurethane resin prepared by the present invention exhibits excellent performance in a variety of application scenarios, especially in the field requiring higher impact strength and ductility. At the same time, the present invention introduces a functional unit with fluorescent properties into the resin through a coordination reaction, so that the obtained shape memory fluorescent polyurethane resin can not only restore to a predetermined shape under external stimuli (such as temperature or stress), but also show a strong and stable fluorescence response under a variety of external stimuli. This advantage makes the shape memory fluorescent polyurethane resin prepared by the present invention have a wider application potential in the fields of intelligent perception, environmental monitoring and medical diagnosis. Finally, the preparation method provided by the present invention is simple and easy, and unnecessary side reactions are reduced during the preparation process, so that the preparation of high-purity and high-yield products can be achieved, and the purity and consistency of the product can be improved. At the same time, a high-yield resin material can be obtained in a shorter time, reducing the production cost.

[0024] The present invention provides a shape memory fluorescent polyurethane resin prepared by the preparation method described in the above technical solution. The shape memory fluorescent polyurethane resin provided by the present invention not only gives the material a shape memory effect, but also, through molecular design and structural optimization, enables the material to have fluorescent properties, thereby meeting multiple functional requirements. The shape memory fluorescent polyurethane resin provided by the present invention can be used not only in shape memory devices, but also in the fields of intelligent sensing, optical imaging, and medical diagnosis. The shape memory fluorescent polyurethane resin provided by the present invention not only improves the comprehensive performance (mechanical properties and fluorescent properties) of the material, but also expands its application range. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The tensile stress-strain curves of the polyurethane products prepared in the examples and comparative examples;

[0026] Figure 2 The toughness of the polyurethane products prepared in the examples and comparative examples;

[0027] Figure 3 Excitation spectra of polyurethane products prepared in Examples and Comparative Examples;

[0028] Figure 4 The emission spectra of the polyurethane products prepared in Examples and Comparative Examples;

[0029] Figure 5 This is the shape memory process of the polyurethane product prepared in Example 1. DETAILED DESCRIPTION

[0030] The present invention provides a method for preparing a shape memory fluorescent polyurethane resin, comprising the following steps:

[0031] (1) mixing polyethylene glycol, hexamethylene diisocyanate, an organic tin catalyst and an organic solvent to carry out a nucleophilic addition reaction to obtain a polyurethane prepolymer reaction solution;

[0032] (2) mixing the polyurethane prepolymer reaction solution and 5,5′-diamino-2,2′-bipyridine to carry out an addition reaction to obtain an addition reaction solution;

[0033] (3) mixing the addition reaction solution and the europium salt to carry out a coordination reaction to obtain a coordination reaction solution;

[0034] (4) removing the solvent from the coordination reaction solution to obtain the shape memory fluorescent polyurethane resin.

[0035] In the present invention, unless otherwise specified, all preparation raw materials / components are commercially available products well known to those skilled in the art.

[0036] The present invention mixes polyethylene glycol, hexamethylene diisocyanate, an organic tin catalyst and an organic solvent (hereinafter referred to as the first mixing) to perform a nucleophilic addition reaction to obtain a polyurethane prepolymer reaction solution. In the present invention, the number average molecular weight of the polyethylene glycol is preferably 5000-8000, and specifically 6000 in the embodiment. Before the first mixing, the present invention preferably pre-dries the polyethylene glycol, and the pre-drying is preferably carried out in an oven, and the pre-drying is preferably vacuum drying. The vacuum drying temperature is preferably 110-130°C, and can be 120°C in the embodiment; the vacuum drying time is preferably 3-6h, and can be 5h in the embodiment. The organic tin catalyst is preferably dibutyltin dilaurate. The organic solvent preferably includes one or more of N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide. The ratio of the mass of the polyethylene glycol to the volume of the hexamethylene diisocyanate is preferably 16-20g:1mL, and can be 18.75g:1mL in the embodiment. The present invention has no special requirement for the amount of the organic tin catalyst, ensuring that the reaction proceeds smoothly, which can be 3 to 5 drops in the embodiment. The present invention has no special requirement for the amount of the organic solvent, ensuring that the raw materials are mixed evenly and the reaction proceeds smoothly.

[0037] In the present invention, the first mixing preferably includes the following steps: premixing the polyethylene glycol, the organic solvent and the organotin catalyst, and then mixing with the hexamethylene diisocyanate. The nucleophilic addition reaction is preferably carried out in a protective gas atmosphere, and the protective gas is preferably nitrogen. The temperature of the nucleophilic addition reaction is preferably 60 to 80°C, and in the embodiment it can be 60°C; the time is preferably 1 to 3 hours, and in the embodiment it can be 3 hours.

[0038] In the present invention, the nucleophilic addition reaction is a reaction between the isocyanate group of hexamethylene diisocyanate and the hydroxyl group in polyethylene glycol to generate a polyurethane prepolymer. The present invention can further improve the mechanical properties of the target product shape memory fluorescent polyurethane resin by controlling the number average molecular weight of the polyethylene glycol, the dosage relationship of the polyethylene glycol and the hexamethylene diisocyanate, and the temperature of the nucleophilic addition reaction, and effectively overcome the inherent contradiction between tensile strength, elongation at break, and toughness.

[0039] After obtaining the polyurethane prepolymer reaction solution, the present invention mixes the polyurethane prepolymer reaction solution and 5,5'-diamino-2,2'-bipyridine for addition reaction to obtain an addition reaction solution. In the present invention, the mass ratio of the polyethylene glycol to the 5,5'-diamino-2,2'-bipyridine is preferably 30 to 35:1, and can be 32.6:1 in the embodiment. In the present invention, the 5,5'-diamino-2,2'-bipyridine is preferably mixed with the polyurethane prepolymer reaction solution in the form of a 5,5'-diamino-2,2'-bipyridine organic solution. The organic solvent in the 5,5'-diamino-2,2'-bipyridine organic solution preferably includes one or more of N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide, and the embodiment is specifically N,N-dimethylformamide. The present invention has no special requirements for the amount of the organic solvent in the 5,5'-diamino-2,2'-bipyridine organic solution.

[0040] In the present invention, the addition reaction is preferably carried out in a protective gas atmosphere, and the protective gas is preferably nitrogen. The temperature of the addition reaction is preferably 60-80° C., and in the embodiment it can be 60° C.; the time of the addition reaction is preferably 15-18 hours, and in the embodiment it can be 15 hours.

[0041] After obtaining the addition reaction solution, the present invention mixes the addition reaction solution and the europium salt for coordination reaction to obtain a coordination reaction solution. In the present invention, the europium salt preferably includes europium chloride. The mass ratio of the 5,5′-diamino-2,2′-bipyridine to the europium salt is preferably 2 to 8.5:1, and in the embodiment it can be 8.1:1, 4.0:1, 2.7:1 or 2.0:1. In the present invention, the europium salt is preferably mixed with the addition reaction solution in the form of an organic solution of europium salt. The organic solvent in the organic solution of europium salt preferably includes one or more of N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide, and in the embodiment it is specifically N,N-dimethylformamide. The present invention has no special requirements for the amount of the organic solvent in the organic solution of europium salt.

[0042] In the present invention, the coordination reaction is preferably carried out in a protective gas atmosphere, and the protective gas is preferably nitrogen. The temperature of the coordination reaction is preferably 60 to 80°C, and in the embodiment it can be 60°C; the time of the coordination reaction is preferably 20 to 30 minutes, and in the embodiment it can be 30 minutes. The coordination reaction is preferably carried out under stirring.

[0043] After obtaining the coordination reaction solution, the present invention removes the solvent from the coordination reaction solution to obtain the shape memory fluorescent polyurethane resin. In the present invention, before the solvent removal, the present invention preferably places the coordination reaction solution in a mold. The temperature of the solvent removal is preferably 70 to 80°C, and the time is limited to 12 to 24 hours. The solvent removal is preferably dried, and the solvent removal is preferably carried out in an oven. The present invention has no special requirements for the shape of the mold. The present invention has no special requirements for the specific implementation of the solvent removal.

[0044] The present invention provides a shape memory fluorescent polyurethane resin prepared by the preparation method described in the above technical scheme.

[0045] The shape memory fluorescent polyurethane resin provided by the present invention optimizes the molecular structure of the polyurethane resin, and the obtained material has high tensile strength, good elongation at break and excellent toughness, and can have good ductility and energy absorption capacity while ensuring the strength of the material. Therefore, the shape memory fluorescent polyurethane resin provided by the present invention exhibits excellent performance in various application scenarios, especially in fields requiring high impact strength and ductility.

[0046] The shape memory fluorescent polyurethane resin provided by the present invention introduces a functional unit with fluorescent properties, so that the resin can not only restore to a predetermined shape under external stimuli (such as temperature or stress), but also show a strong and stable fluorescent response under a variety of external stimuli. This advantage makes the material have a wider application potential in the fields of intelligent perception, environmental monitoring and medical diagnosis.

[0047] The present invention provides the use of the shape memory fluorescent polyurethane resin described in the above technical solution in shape memory devices, intelligent sensing, optical sensing or the preparation of medical diagnostic materials.

[0048] The present invention has no special requirements on the specific implementation of the application.

[0049] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0050] The reaction gas environment in the following examples and comparative example 1 is nitrogen.

[0051] Example 1

[0052] (1) Weigh 15 g of polyethylene glycol into a three-necked flask and place it in a 120°C oven under vacuum for 5 h. Then, add 40 mL of N,N-dimethylformamide and 5 drops of dibutyltin dilaurate and stir evenly.

[0053] (2) 0.8 mL of hexamethylene diisocyanate was added to the three-necked flask in step (1) and reacted at 60° C. for 3 h.

[0054] (3) Weigh 0.46 g of 5,5′-diamino-2,2′-bipyridine and dissolve it in 20 mL of N,N-dimethylformamide. Add the mixture into the three-necked flask in step (2) and react at 60° C. for 15 h.

[0055] (4) Weigh 0.057 g of europium chloride and dissolve it in 5 mL of N,N-dimethylformamide. Add it to the three-necked flask in step (3) and stir it at 60°C for 30 min. Then pour it into the mold, put the mold in an oven at 80°C for 12 hours, remove the solvent, and obtain the target material shape memory fluorescent polyurethane, which is recorded as PU-0.25-Eu 3+ .

[0056] Example 2

[0057] (1) Weigh 15 g of polyethylene glycol into a three-necked flask and place it in a 120°C oven under vacuum for 5 h. Then, add 40 mL of N,N-dimethylformamide and 5 drops of dibutyltin dilaurate and stir evenly.

[0058] (2) 0.8 mL of hexamethylene diisocyanate was added to the three-necked flask in step (1) and reacted at 60° C. for 3 h.

[0059] (3) Weigh 0.46 g of 5,5′-diamino-2,2′-bipyridine and dissolve it in 20 mL of N,N-dimethylformamide. Add the mixture into the three-necked flask in step (2) and react at 60° C. for 15 h.

[0060] (4) Weigh 0.114 g of europium chloride and dissolve it in 6 mL of N,N-dimethylformamide. Add it to the three-necked flask in step (3) and stir it at 60°C for 30 min. Then pour it into the mold, put the mold in an oven at 80°C for 12 hours, remove the solvent, and obtain the target material shape memory fluorescent polyurethane, which is recorded as PU-0.5-Eu 3+ .

[0061] Example 3

[0062] (1) Weigh 15 g of polyethylene glycol into a three-necked flask and place it in a 120°C oven under vacuum for 5 h. Then, add 40 mL of N,N-dimethylformamide and 5 drops of dibutyltin dilaurate and stir evenly.

[0063] (2) 0.8 mL of hexamethylene diisocyanate was added to the three-necked flask in step (1) and reacted at 60° C. for 3 h.

[0064] (3) Weigh 0.46 g of 5,5′-diamino-2,2′-bipyridine and dissolve it in 20 mL of N,N-dimethylformamide. Add the mixture into the three-necked flask prepared in step (2) and react at 60° C. for 15 h.

[0065] (4) Weigh 0.171 g of europium chloride and dissolve it in 7 mL of N,N-dimethylformamide. Add it to the three-necked flask in step (3) and stir it at 60°C for 30 min. Then pour it into the mold, put the mold into an oven at 80°C for 12 hours, remove the solvent, and obtain the target material shape memory fluorescent polyurethane, which is recorded as PU-0.75-Eu 3+ .

[0066] Example 4

[0067] (1) Weigh 15 g of polyethylene glycol into a three-necked flask, place in an oven at 120° C. and vacuum dry for 5 h, take out and add 40 mL of N,N-dimethylformamide and 5 drops of dibutyltin dilaurate, and stir evenly.

[0068] (2) 0.8 mL of hexamethylene diisocyanate was added to the three-necked flask in step (1) and reacted at 60° C. for 3 h.

[0069] (3) Weigh 0.46 g of 5,5′-diamino-2,2′-bipyridine and dissolve it in 20 mL of N,N-dimethylformamide. Add the mixture into the three-necked flask in step (2) and react at 60° C. for 15 h.

[0070] (4) Weigh 0.228 g of europium chloride and dissolve it in 8 mL of N,N-dimethylformamide. Add it to the three-necked flask in step (3) and stir it at 60°C for 30 min. Then pour it into the mold, put the mold in an oven at 80°C for 12 hours, remove the solvent, and obtain the target material shape memory fluorescent polyurethane, which is recorded as PU-1-Eu 3+ .

[0071] Comparative Example 1

[0072] (1) Weigh 15 g of polyethylene glycol into a three-necked flask, place in an oven at 120° C. and vacuum dry for 5 h, take out and add 40 mL of N,N-dimethylformamide and 5 drops of dibutyltin dilaurate, and stir evenly.

[0073] (2) 0.8 mL of hexamethylene diisocyanate was added to the three-necked flask in step (1) and reacted at 60° C. for 3 h.

[0074] (3) Weigh 0.46 g of 5,5′-diamino-2,2′-bipyridine and dissolve it in 20 mL of N,N-dimethylformamide, add it to the three-necked flask in step (2) and react at 60°C for 15 h. Then pour it into a mold and remove the solvent to obtain the target material polyurethane, which is recorded as PU-0-Eu 3+ .

[0075] Test Case

[0076] (1) The tensile stress-strain curves of the shape memory fluorescent polyurethanes prepared in Examples 1 to 4 and the polyurethane prepared in Comparative Example 1 are as follows: Figure 1 As shown, the adopted standard is ISO527-2:2012.

[0077] (2) The toughness test results of the shape memory fluorescent polyurethanes prepared in Examples 1 to 4 and the polyurethane prepared in Comparative Example 1 are as follows: Figure 2 As shown, the adopted standard is ISO527-2:2012.

[0078] (3) The excitation spectra of the shape memory fluorescent polyurethanes prepared in Examples 1 to 4 and the polyurethane prepared in Comparative Example 1 are as follows: Figure 3 shown.

[0079] (4) The emission spectra of the shape memory fluorescent polyurethanes prepared in Examples 1 to 4 and the polyurethane prepared in Comparative Example 1 are as follows: Figure 4 shown.

[0080] (5) The shape memory process of the shape memory fluorescent polyurethane prepared in Example 1 is as follows Figure 5 shown.

[0081] Depend on Figure 1 and Figure 2 It can be seen that the shape memory fluorescent polyurethane prepared in Examples 1 to 4 provided by the present invention, wherein the shape memory fluorescent polyurethane product prepared in Example 1 has better mechanical properties than other examples and Comparative Example 1, wherein the shape memory fluorescent polyurethane prepared in Example 1 has a tensile strength of 47.18±2.35MPa, an elongation at break (the standard adopted is ISO527-2:2012) of 5952.72±254.20%, and a toughness of 1396.39±90.05MJ / m 3 Compared with the product in comparative example 1, the strength is increased by 1.36 times and the toughness is increased by 1.75 times.

[0082] Depend on Figure 3 It can be observed that the shape memory fluorescent polyurethane materials prepared in Examples 1 to 4 provided by the present invention can be excited and emit fluorescence at a specific wavelength. Among them, Example 1 can be excited by 427nm light, Figure 4It was observed that Example 1 could emit green fluorescence with a wavelength of 497 nm under the optimal excitation wavelength.

[0083] Depend on Figure 5 The shape memory process of the shape memory fluorescent polyurethane prepared in Example 1 can be observed. The initial shape is a square. The material is deformed by pulling at 80°C, and then the temporary shape is fixed at room temperature. After heating to 80°C again, the material returns to the initial square.

[0084] From the above embodiments, it can be seen that the present invention introduces a functional unit with fluorescent properties into the molecular structure of the polyurethane resin, and optimizes the type, dosage ratio and reaction conditions of the reaction raw materials, so that the prepared shape memory fluorescent polyurethane resin not only has an excellent shape memory effect, but also can show a strong fluorescence response under a variety of external stimuli, and has high light stability and mechanical strength. The preparation method of the shape memory fluorescent polyurethane resin provided by the present invention is simple and controllable. The shape memory fluorescent polyurethane resin provided by the present invention can provide new application opportunities in multiple fields, especially in the fields of intelligent sensing, medical diagnosis and environmental monitoring. Therefore, the present invention not only solves the problem of incompatibility between the performance of shape memory materials and fluorescent materials in the prior art, but also provides a new idea for the research and development of high-performance intelligent materials.

[0085] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing a shape memory fluorescent polyurethane resin, characterized in that: The following steps are involved: (1) mixing polyethylene glycol, hexamethylene diisocyanate, an organic tin catalyst and an organic solvent to carry out a nucleophilic addition reaction to obtain a polyurethane prepolymer reaction solution; (2) mixing the polyurethane prepolymer reaction solution and 5,5′-diamino-2,2′-bipyridine to carry out an addition reaction to obtain an addition reaction solution; (3) mixing the addition reaction solution and the europium salt to carry out a coordination reaction to obtain a coordination reaction solution; (4) removing the solvent from the coordination reaction solution to obtain the shape memory fluorescent polyurethane resin.

2. The preparation method according to claim 1, characterized in that: The number average molecular weight of the polyethylene glycol is 5000-8000.

3. The preparation method according to claim 1 or 2, characterized in that: The ratio of the mass of the polyethylene glycol to the volume of the hexamethylene diisocyanate is 16-20 g:1 mL.

4. The preparation method according to claim 1, characterized in that: In step (1), the temperature of the nucleophilic addition reaction is 60 to 80° C. and the time is 1 to 3 hours.

5. The preparation method according to claim 1 or 2, characterized in that: The mass ratio of the polyethylene glycol to the 5,5′-diamino-2,2′-bipyridine is 30 to 35:

1.

6. The preparation method according to claim 1, characterized in that: In step (2), the temperature of the addition reaction is 60 to 80° C. and the time is 15 to 18 hours.

7. The preparation method according to claim 1, characterized in that: The europium salt includes europium chloride.

8. The preparation method according to claim 1 or 7, characterized in that: The mass ratio of the 5,5′-diamino-2,2′-bipyridine to the europium salt is 2 to 8.5:1; The temperature of the coordination reaction is 60-80° C. and the time is 20-30 minutes.

9. The shape memory fluorescent polyurethane resin prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the shape memory fluorescent polyurethane resin according to claim 9 in shape memory devices, intelligent sensing, optical sensing or preparation of medical diagnostic materials.

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