Degradable flexible x-ray scintillator thin film and closed loop regeneration method thereof

Abstract

The application discloses a degradable flexible X-ray scintillator film and a closed-loop regeneration method thereof, and relates to the technical field of functional materials; in the scheme, palm modified cellulose ester is used as a film substrate, and europium-based organic scintillators are uniformly dispersed in the film substrate to form a flexible, hydrophobic and thermoplastic X-ray scintillator film; the X-ray scintillator film has excellent X-ray response performance, thermoplasticity, environmental stability and mechanical flexibility; the europium-based scintillator powder and the palm modified cellulose ester can be separated through a solvent, and the palm modified cellulose ester is biodegradable; the prepared X-ray scintillator film solves the problems of the traditional scintillator, such as non-recyclability, rigidity and environmental unfriendliness.

Description

Technical Field

[0001] This invention relates to the field of functional materials technology, specifically a biodegradable flexible X-ray scintillator film and its closed-loop regeneration method. Background Technology

[0002] Traditional scintillator materials are mainly based on inorganic crystals (such as LYSO and BGO) or synthetic polymer composites, which have problems such as high energy consumption in preparation, non-recyclability, high rigidity, and environmental unfriendliness. In recent years, although organic scintillators (such as europium complexes) have improved in flexibility and sensitivity, their matrices mostly rely on petroleum-based polymers (such as PET and PMMA) and lack closed-loop recycling mechanisms, making it difficult to achieve sustainable development.

[0003] Cellulose, as a renewable and biodegradable natural polymer, has attracted much attention due to its wide availability and environmental friendliness. However, unmodified cellulose is highly hydrophilic, has poor compatibility with organic scintillators, and is prone to phase separation, which limits its application in scintillators.

[0004] Therefore, it is of great significance to develop a scintillator thin film that combines high performance, recyclability, and biodegradability. Summary of the Invention

[0005] The purpose of this invention is to provide a biodegradable flexible X-ray scintillator film and a closed-loop regeneration method thereof to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A biodegradable flexible X-ray scintillator film, the preparation method of the X-ray scintillator film includes the following steps: adding palm-modified cellulose ester and europium-based scintillator to a solvent in sequence and mixing them, then performing casting molding and step drying treatment in sequence to obtain the X-ray scintillator film; The mass ratio of palm-modified cellulose ester to europium-based scintillator is 5:1 to 1:2.

[0007] In this scheme, microcrystalline cellulose is first added to methanol for removal treatment; europium-based scintillator is in powder form; and the substrate used for casting is a solvent-resistant substrate such as a glass sheet, silicon wafer, or quartz sheet.

[0008] A more optimized method for preparing the palm-modified cellulose ester is as follows: under an inert gas atmosphere, microcrystalline cellulose, palmitoyl chloride, and pyridine are sequentially added to a lithium chloride-N,N-dimethylacetamide solution for esterification reaction, followed by post-treatment to obtain the palm-modified cellulose ester.

[0009] In a more optimized configuration, the molar ratio of palmitoyl chloride to glucose units in microcrystalline cellulose is 2:1 to 5:1.

[0010] A more optimized method for preparing the europium-based scintillator is as follows: (1) BINAP (2,2'-bis(diphenylphosphine)-1,1'-binaphthyl) is added to tetrahydrofuran, hydrogen peroxide is added dropwise, an oxidation reaction is performed, and after treatment, BINAPO (oxidized 2,2'-bis(diphenylphosphine)-1,1'-binaphthyl) is obtained, which is white in color; (2) 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione, BINAPO (oxidized 2,2'-bis(diphenylphosphine)-1,1'-binaphthyl) and sodium hydroxide are added to ethanol and stirred and mixed, europium chloride aqueous solution is added dropwise, a coordination reaction is performed, and europium-based scintillator is obtained, which is pale yellow in color.

[0011] In a more optimized form, the raw material for BINAPO comprises the following components: 1-5 parts by mass of BINAP and 5-20 parts by mass of hydrogen peroxide; the raw material for the europium-based scintillator comprises the following components: 0.2-1.5 parts by mass of 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione, 0.5-3 parts by mass of BINAPO, and 0.5-3 parts by mass of europium chloride aqueous solution; the concentration of the europium chloride aqueous solution is 100-150 mg / mL.

[0012] A more optimized process is as follows: heat to 35-45°C, hold for 2-3 hours, then heat to 70-90°C and hold for 10-30 minutes.

[0013] A closed-loop regeneration method for a biodegradable flexible X-ray scintillator film includes the following steps: (1) The used X-ray scintillator film was recovered, cut into pieces and added to tetrahydrofuran for uniform mixing. Ethanol was added, stirred at room temperature, and centrifuged to obtain precipitate and supernatant. (2) The dried precipitate and europium-based scintillator were added to tetrahydrofuran and mixed, then cast and dried in a stepwise manner to obtain a recyclable X-ray scintillator film.

[0014] More optimized, the solid-liquid ratio of the X-ray scintillator film to tetrahydrofuran is (10~50) mg:1 mL; the volume ratio of tetrahydrofuran to ethanol is 1:20~1:50.

[0015] In a more optimized form, the dried precipitate is a recovered palm-modified cellulose ester; the supernatant contains a europium scintillator; the mass ratio of the recovered palm-modified cellulose ester to the europium scintillator is 5:1 to 1:2; and the recyclable X-ray scintillator film has an X-ray sensitivity detection limit as low as 67.15 nGy / s.

[0016] In the scheme, ethanol is used as the precipitant for palm-modified cellulose esters; the supernatant is recast into a film for soil degradation experiments.

[0017] Europium-based organic scintillators are loaded and mixed into palm-modified cellulose ester-based films to obtain X-ray scintillator films. Europium-based organic scintillators have the property of X-ray radiation emission and can be used as X-ray scintillators. They can be widely used in flexible displays for non-destructive imaging in biology and industry.

[0018] Compared with the prior art, the beneficial effects of the present invention are: 1. The solution film-forming process adopted is mild and easy to operate. The preparation process is simple and highly scalable, suitable for large-area preparation and industrial production, and has good application prospects and economic benefits.

[0019] 2. Microcrystalline cellulose film materials possess hydrophobicity, thermoplasticity, radiative luminescence, and mechanical toughness, which can meet the needs of various complex application scenarios (such as medical imaging, industrial inspection, flexible electronics, etc.), breaking through the limitations of traditional materials with single functions.

[0020] 3. The X-ray scintillator film prepared by this invention not only has excellent X-ray sensitivity (detection limit as low as 67.15 nGy / s) and high spatial resolution (16 lp / mm), but also has good mechanical flexibility and can be reshaped at 80°C, making it suitable for curved surfaces or wearable devices.

[0021] 4. Using recyclable microcrystalline cellulose as a matrix reduces dependence on petroleum-based plastics; at the same time, europium-based scintillators can be recycled and reused multiple times, reducing the pressure on rare earth resource mining.

[0022] 5. Europium-based scintillators and palm-modified cellulose esters can be separated and reused through mild solvent treatment. The palm-modified cellulose esters are partially biodegradable, achieving true closed-loop recycling and degradation, which significantly reduces the environmental pollution caused by electronic waste. Attached Figure Description

[0023] Figure 1 This is a diagram of the X-ray scintillator film prepared in Example 1 under natural light; Figure 2 The image shows the X-ray scintillator film prepared in Example 1 under ultraviolet light; Figure 3 The X-ray scintillator thin film prepared in Example 2 shows its radiation emission spectrum. Figure 4 The graph shows the linear relationship between the radiation intensity of the X-ray scintillator thin film prepared in Example 2 and the dose rate. Figure 5 This is a schematic diagram of the X-ray scintillator thin film and circuitry prepared in Example 3, arranged as a flat film. Figure 6 This is a schematic diagram of the X-ray scintillator thin film prepared in Example 3 and the circuit being attached as a thin film. Figure 7 The graph shows the change in response intensity of a flat film as a function of distance in a specific region under X-ray irradiation. Figure 8 A graph showing the change in the response intensity of the laminated film as a function of distance in a specific region under X-ray irradiation. Figure 9 This is a schematic diagram of the surface cleaning process of the X-ray scintillator thin film prepared in Example 4; Figure 10 The X-ray scintillator film prepared in Example 4 was immersed in water for 0 days, and the images were taken under natural light and ultraviolet light. Figure 11 The X-ray scintillator film prepared in Example 4 was immersed in water for 10 days, and the images were taken under natural light and ultraviolet light. Figure 12 The X-ray scintillator film prepared in Example 4 was immersed in water for 20 days, and the images were taken under natural light and ultraviolet light. Figure 13 The X-ray scintillator film prepared in Example 4 was immersed in water for 30 days, and the images were taken under natural light and ultraviolet light. Figure 14 The image shows the soil degradation of the X-ray scintillator film prepared in Example 5 on day 0. Figure 15 The image shows the soil degradation of the X-ray scintillator film prepared in Example 5 after 180 days. Detailed Implementation

[0024] 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 some embodiments of the present invention, and not all embodiments. 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. In the following embodiments, parts are by weight.

[0025] Example 1: A closed-loop regeneration method for a biodegradable flexible X-ray scintillator film, comprising the following steps: Step 1: Palm-modified cellulose ester: Under inert gas, microcrystalline cellulose was dispersed in a lithium chloride-N,N-dimethylacetamide solution (lithium chloride accounted for 8 wt% of the lithium chloride-N,N-dimethylacetamide solution). Palmitoyl chloride and pyridine were added sequentially at 60°C. After reacting for 1 hour, the precipitate was added to ethanol, centrifuged to collect the precipitate, and dried to obtain palm-modified cellulose ester. The molar ratio of palmitoyl chloride to glucose units in microcrystalline cellulose was 5:1. Europium scintillator: (1) Add 3 parts of BINAP (2,2'-bis(diphenylphosphine)-1,1'-binaphthyl) to 25 parts of tetrahydrofuran, add 17 parts of hydrogen peroxide, oxidize for 3 hours, remove tetrahydrofuran by rotary evaporation, add dichloromethane and water for extraction, dry the organic phase with anhydrous sodium sulfate to obtain BINAPO (oxidized 2,2'-bis(diphenylphosphine)-1,1'-binaphthyl); (2) Add 1 part of 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione, 1.7 parts of BINAPO (oxidized 2,2'-bis(diphenylphosphine)-1,1'-binaphthyl), and 0.16 parts of sodium hydroxide to ethanol and stir to mix, add 2.5 parts of europium chloride aqueous solution, coordinate reaction for 5 hours, remove ethanol by rotary evaporation, dry to obtain europium scintillator; Step 2: Palm-modified cellulose ester and europium-based scintillator are added sequentially to tetrahydrofuran and mixed, then cast and dried in a stepwise manner to obtain an X-ray scintillator film (approximately 50 μm thick); the molar ratio of palmitoyl chloride to glucose units in microcrystalline cellulose is 5:1; Step 3: (1) Recover the used X-ray scintillator film, cut it into pieces and add it to tetrahydrofuran and mix (until the film is completely dissolved). The solid-liquid ratio of the X-ray scintillator film to tetrahydrofuran is 10 mg: 1 mL. Add ethanol (ethanol is 10 times that of tetrahydrofuran), stir at room temperature for 2 hours, centrifuge to obtain precipitate (palm-modified cellulose ester) and supernatant (containing europium scintillator). (2) The dried precipitate (recycled palm-modified cellulose ester) and europium-based scintillator were added to tetrahydrofuran at a mass ratio of 5:1 and mixed. The mixture was then cast and dried in stages (held at 35°C for 3 hours and then at 75°C for 20 minutes) to obtain a recyclable X-ray scintillator film. The mechanical properties of the recyclable X-ray scintillator film were retained at a rate greater than 95%, and the X-ray imaging performance was not significantly reduced.

[0026] Example 2 is based on Example 1, except that step 1 is different, while the other operation steps remain the same; Step 1: Palm-modified cellulose ester: Under inert gas, microcrystalline cellulose was dispersed in a lithium chloride-N,N-dimethylacetamide solution (lithium chloride accounted for 8 wt% of the lithium chloride-N,N-dimethylacetamide solution). Palmitoyl chloride and pyridine were added sequentially at 60°C. After reacting for 1 hour, the precipitate was added to ethanol, centrifuged to collect the precipitate, and dried to obtain palm-modified cellulose ester. The molar ratio of palmitoyl chloride to glucose units in microcrystalline cellulose was 5:1. Europium scintillator: (1) Add 3 parts of BINAP (2,2'-bis(diphenylphosphine)-1,1'-binaphthyl) to 25 parts of tetrahydrofuran, add 17 parts of hydrogen peroxide, oxidize for 3 hours, remove tetrahydrofuran by rotary evaporation, add dichloromethane and water for extraction, dry the organic phase with anhydrous sodium sulfate to obtain BINAPO (oxidized 2,2'-bis(diphenylphosphine)-1,1'-binaphthyl); (2) Add 1 part of 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione, 1.7 parts of BINAPO (oxidized 2,2'-bis(diphenylphosphine)-1,1'-binaphthyl), and 0.16 parts of sodium hydroxide to ethanol and stir to mix, add 2.5 parts of europium chloride aqueous solution, coordinate reaction for 5 hours, remove ethanol by rotary evaporation, dry to obtain europium scintillator.

[0027] Example 3 is based on Example 1, except that step 2 is different, while the other operation steps remain the same; Step 2: Take palm-modified cellulose ester solution (concentration of palm-modified cellulose ester solution is 10 mg / mL) and europium scintillator and add them to tetrahydrofuran and mix them. Then perform casting molding and step drying to obtain X-ray scintillator film (thickness of about 50 μm); the molar ratio of palmitoyl chloride to glucose units in microcrystalline cellulose is 2:1. Example 4 is based on Example 1, except that step 2 is different, while the other operation steps remain the same; Step 2: Palm-modified cellulose ester and europium-based scintillator are added sequentially to tetrahydrofuran and mixed, then cast and dried in stages to obtain an X-ray scintillator film (approximately 200 μm thick); the molar ratio of palmitoyl chloride to glucose units in microcrystalline cellulose is 5:1.

[0028] Example 5 is based on Example 4, except that step 3 is different, while the other operation steps remain the same; Step 3: (1) Recover the used X-ray scintillator film, cut it into pieces and add it to tetrahydrofuran and mix (until the film is completely dissolved). The solid-liquid ratio of the X-ray scintillator film to tetrahydrofuran is 10 mg: 1 mL. Add ethanol (ethanol is 50 times that of tetrahydrofuran), stir at room temperature for 2 hours, centrifuge to separate the precipitate (palm-modified cellulose ester) and the supernatant (containing europium scintillator). (2) The dried precipitate (recovered palm-modified cellulose ester) and europium-based scintillator were added to tetrahydrofuran at a mass ratio of 5:1 and mixed. The mixture was then cast and dried in stages to obtain a regenerated X-ray scintillator film. The supernatant was recast into a film for soil degradation experiments (e.g., Figures 14-15 The recyclable X-ray scintillator film retains more than 95% of its mechanical properties and exhibits no significant decrease in X-ray imaging performance.

[0029] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A biodegradable flexible X-ray scintillator thin film, characterized in that: The preparation method of the X-ray scintillator film includes the following steps: palm-modified cellulose ester obtained by esterification reaction of microcrystalline cellulose and palmitoyl chloride, europium scintillator are added to a solvent in sequence and mixed, and then cast and dried in sequence to obtain X-ray scintillator film; The mass ratio of palm-modified cellulose ester to europium-based scintillator is 5:1 to 1:

2. The preparation method of the europium-based scintillator is as follows: (1) Add BINAP to tetrahydrofuran, add hydrogen peroxide dropwise, perform oxidation reaction, and then perform post-treatment to obtain BINAPO; (2) Add 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione, BINAPO, and sodium hydroxide to ethanol and stir to mix, add europium chloride aqueous solution dropwise, perform coordination reaction, and obtain europium-based scintillator.

2. The biodegradable flexible X-ray scintillator thin film according to claim 1, characterized in that: The preparation method of the palm-modified cellulose ester is as follows: under inert gas, microcrystalline cellulose, palmitoyl chloride and pyridine are added sequentially to a lithium chloride-N,N-dimethylacetamide solution for esterification reaction, followed by post-treatment to obtain the palm-modified cellulose ester.

3. The biodegradable flexible X-ray scintillator thin film according to claim 2, characterized in that: The molar ratio of palmitoyl chloride to glucose units in microcrystalline cellulose is 2:1 to 5:

1.

4. The biodegradable flexible X-ray scintillator thin film according to claim 1, characterized in that: The raw materials for BINAPO include the following components: by mass, 1-5 parts BINAP and 5-20 parts hydrogen peroxide; The raw material of the europium-based scintillator It comprises the following components: by mass, 0.2 to 1.5 parts of 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione, 0.5 to 3 parts of BINAPO, and 0.5 to 3.5 parts of europium chloride aqueous solution; wherein the concentration of the europium chloride aqueous solution is 100 to 150 mg / mL.

5. The biodegradable flexible X-ray scintillator thin film according to claim 1, characterized in that: The process conditions for the stepped drying treatment are as follows: heat up to 35~45℃, maintain for 2~3 hours, continue to heat up to 70~90℃, and maintain for 10~30 minutes.

6. The closed-loop regeneration method for a biodegradable flexible X-ray scintillator film according to claim 1, characterized in that: The following steps are included: (1) The used X-ray scintillator film was recovered, cut into pieces and added to tetrahydrofuran for uniform mixing. Ethanol was added, stirred at room temperature, and centrifuged to obtain precipitate and supernatant. (2) The dried precipitate and europium-based scintillator were added to tetrahydrofuran and mixed, then cast and dried in a stepwise manner to obtain a recyclable X-ray scintillator film.

7. The closed-loop regeneration method for a biodegradable flexible X-ray scintillator film according to claim 6, characterized in that: The solid-liquid ratio of the X-ray scintillator film to tetrahydrofuran is (10~50) mg:1 mL; the volume ratio of tetrahydrofuran to ethanol is 1:20~1:

50.

8. The closed-loop regeneration method for a biodegradable flexible X-ray scintillator film according to claim 6, characterized in that: The dried precipitate is a recovered palm-modified cellulose ester, and the supernatant contains europium-based scintillators; the mass ratio of the recovered palm-modified cellulose ester to europium-based scintillators is 5:1 to 1:2; the recyclable X-ray scintillator film has an X-ray sensitivity detection limit as low as 67.15 nGy / s.

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