Peelable decontamination material with uranium developing and tracing function, preparation method and application

Abstract

The invention belongs to the technical field of nuclear pollution decontamination, and particularly discloses a strippable decontamination material with a uranium developing and tracing function as well as a preparation method and application of the strippable decontamination material with the uranium developing and tracing function. The strippable decontamination material is prepared by taking polyvinyl alcohol (PVA) and the like as film-forming base materials and 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Br-PADAP) as a developing indicator; and an amphiphilic block copolymer PEA-b-PAA prepared by RAFT polymerization is innovatively adopted as a dispersing agent, so that the technical problems that Br-PADAP is poor in dispersity and easy to agglomerate in a water-based system are effectively solved. The material can be subjected to complexation reaction with uranium pollutants in the decontamination process, color change visible to naked eyes is generated, and visual tracing of a polluted area is achieved; meanwhile, the film-forming property is excellent, complete stripping can be achieved after curing, the decontamination rate on the surfaces of various base materials is all higher than 90%, and the detection limit on uranium can reach 0.81 * 10 <-6 > mol / cm < 2 >. The method is easy and convenient to operate, environmentally friendly and particularly suitable for rapid identification and removal of large-range uranium pollution in nuclear facility decommissioning and accident emergency.

Description

Technical Field

[0001] This invention relates to the field of nuclear contamination decontamination technology, specifically to a peelable decontamination material with uranium colorimetric tracing function, its preparation method, and its application. Background Technology

[0002] In the decommissioning of nuclear facilities, emergency response to nuclear accidents, and routine nuclear operations, the control and removal of radioactive contamination are crucial for ensuring personnel safety and environmental health. Uranium (U), as a primary nuclear fuel and fission product, is one of the most common radioactive contaminants. Traditional radioactive decontamination methods include physical wiping, chemical cleaning, and high-pressure water jetting; however, these methods generally suffer from problems such as complex operation, susceptibility to secondary contamination, low decontamination efficiency, and the inability to assess decontamination effectiveness in real time.

[0003] Peelable decontamination materials, as a highly efficient and convenient decontamination technology, have received widespread attention in recent years. They work by coating a contaminated surface with a polymer film, adsorbing and fixing contaminants within the film. After curing, the contaminants are removed entirely through physical peeling, offering advantages such as ease of operation, low waste volume, and low risk of secondary pollution. However, most existing peelable decontamination materials are functionally limited, only possessing decontamination capabilities and unable to provide real-time, intuitive feedback on the presence, distribution, and degree of decontamination of contaminants. Construction personnel cannot quickly identify contamination boundaries and levels on-site, posing significant challenges to the delineation of control zones, adjustment of decontamination strategies, and immediate assessment of decontamination effectiveness.

[0004] To endow detergency materials with tracer functionality, researchers attempted to introduce colorimetric indicators into the material system. Among these, 2-(5-bromo-2-pyridinium azo)-5-diethylaminophenol (Br-PADAP) is particularly useful because it can react with uranyl ions (UO2). 2+ Br-PADAP undergoes a specific complexation reaction and produces a noticeable color change (from orange to purplish-red), making it an ideal colorimetric indicator for uranium contamination. However, Br-PADAP molecules are highly hydrophobic and exhibit extremely poor dispersibility in aqueous systems (especially environmentally friendly water-based strippable decontaminant coatings), readily agglomerating and settling. This not only leads to uneven color development and decreased sensitivity, severely affecting the reliability of the tracing function, but also damages the film-forming uniformity and mechanical properties of the coating, ultimately resulting in a decrease in decontamination efficiency.

[0005] Therefore, developing a novel peelable decontamination material that can effectively solve the dispersion problem of colorimetric indicators and has both high-efficiency decontamination capability and real-time visual tracing function is of great practical need and significant application value for improving the intelligence level and operational efficiency of nuclear facility decommissioning and emergency decontamination operations. Summary of the Invention

[0006] To address the problems of poor dispersibility and easy aggregation and sedimentation of the colorimetric indicator Br-PADAP in aqueous strippable decontamination systems, leading to uneven color development and low sensitivity, this invention provides a strippable decontamination material with uranium colorimetric tracing function, its preparation method, and its application. This material not only achieves efficient decontamination but also provides real-time, intuitive, and visual tracing of uranium contamination through color changes, solving the problem of not being able to quickly identify the range and degree of contamination during the decontamination process. While achieving the above functions, the material ensures good film-forming properties, strippability, and mechanical properties, meeting practical application requirements and solving the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a peelable decontamination material with uranium colorimetric tracing function, wherein the peelable decontamination material with uranium colorimetric tracing function comprises, by weight, the following components:

[0008] Polymer film-forming substrate: 100 parts;

[0009] Colorimetric indicator 2-(5-bromo-2-pyridiniazo)-5-diethylaminophenol Br-PADAP: 0.001–0.003 parts;

[0010] Amphiphilic block copolymer dispersant: 1-8 parts;

[0011] The amphiphilic block copolymer dispersant is polyethyl acrylate-block-polyacrylic acid PEA-b-PAA.

[0012] Preferably, the peelable decontamination material with uranium colorimetric tracing function further includes one or more of the following additives: 0.1 to 0.5 parts of masking agent EDTA; 3 to 5 parts of plasticizer glycerol.

[0013] Preferably, the PEA-b-PAA is prepared by reversible addition-fragmentation chain transfer polymerization of ethyl acrylate (EA) and acrylic acid (AA), with a monomer feed ratio of EA:AA of 1 to 2:1.

[0014] Preferably, the monomer feed ratio of PEA-b-PAA is EA:AA of 1.5:1.

[0015] Preferably, the amount of the amphiphilic block copolymer dispersant added is 4 parts.

[0016] Preferably, the polymer film-forming substrate is polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), or a mixture of the two.

[0017] On the other hand, to achieve the above objectives, the present invention also provides the following technical solution: a method for preparing a peelable decontamination material with uranium colorimetric tracing function, comprising the following steps:

[0018] S1. Preparation of amphiphilic block copolymer dispersant PEA-b-PAA;

[0019] S2. Preparation of indicator dispersion: Dissolve Br-PADAP in an ethanol solution containing PEA-b-PAA and stir thoroughly to obtain the indicator dispersion;

[0020] S3. Preparation of substrate solution: Dissolve the polymer film-forming substrate in deionized water, heat and stir until completely dissolved to obtain the substrate solution;

[0021] S4. Preparation of peelable decontamination material: Add indicator dispersion and additives to substrate solution, stir and mix evenly, and adjust pH to 8.0-8.5 to obtain the peelable decontamination material with uranium colorimetric tracing function.

[0022] Preferably, in step S1, the preparation of the amphiphilic block copolymer dispersant PEA-b-PAA includes the following:

[0023] Using S,S,S-trithiodibenzyl carbonate (DBTTC) as the RAFT reagent and azobisisobutyronitrile (AIBN) as the initiator, ethyl acrylate (EA) monomer was first added to anhydrous ethanol solvent for the first stage of polymerization to obtain the macromolecular chain transfer agent PEA-CTA; then acrylic acid monomer (AA) monomer was added for the second stage of polymerization to obtain the PEA-b-PAA amphiphilic block copolymer.

[0024] On the other hand, in order to achieve the above objectives, the present invention also provides the following technical solution: the application of a peelable decontamination material with uranium colorimetric tracing function for visual decontamination and tracing of uranium-contaminated surfaces during nuclear facility decommissioning and nuclear accident emergency response.

[0025] Preferably, a peelable decontamination material with uranium colorimetric tracing function is uniformly coated onto the surface of the contaminated substrate and cured into a film at room temperature. Upon contact with uranium contaminants, a visible color change occurs within one minute, from an initial milky white to a purplish-red color. The detection limit for uranium contamination can reach as low as 0.81 × 10⁻⁶. -6 mol / cm 2 The membrane has a tensile strength of up to 1.85 MPa, an elongation at break of up to 285%, and a peel strength of up to 0.15 N / mm, making it easy to peel completely from the substrate surface.

[0026] The beneficial effects of this invention are: It possesses excellent dispersibility and stability. Specifically, by innovatively employing the RAFT polymerization method to synthesize the amphiphilic block copolymer PEA-b-PAA as a dedicated dispersant, the hydrophobic segment (PEA) in its molecular chain can effectively bind with Br-PADAP molecules, while the hydrophilic segment (PAA) extends into the aqueous medium to provide steric stabilization, fundamentally solving the aggregation problem of Br-PADAP in aqueous systems, enabling it to be stably and uniformly dispersed in coatings for a long period. The sensitive colorimetric tracking function benefits from the excellent dispersion state of the indicator, which interacts with uranyl ions (UO2). 2+ The complexation reaction is more complete and rapid, producing a sensitive and uniform color change visible to the naked eye, ranging from orange to purplish-red. This enables real-time, intuitive, and visual tracing of the extent and degree of uranium contamination, with a detection limit as low as 0.81 × 10⁻⁶. -6 mol / cm 2 Highly efficient decontamination performance, demonstrating excellent decontamination effects on large areas of loose contaminants on various substrates such as glass, epoxy resin, metal, and plastic, with a decontamination rate of over 90%, reaching up to 99.7%; Enhanced comprehensive performance, namely, the addition of the PEA-b-PAA dispersant, which not only solves the indicator dispersion problem but also acts as a polymeric additive to improve the network structure of the film-forming substrate, thereby enhancing the mechanical properties (such as elongation at break and tensile strength) and peelability of the cured film to a certain extent, making it more conducive to actual construction operations and complete peeling; Environmentally friendly and easy to operate, this invention mainly uses water as a solvent, avoiding the large-scale use of organic solvents, making it environmentally friendly. Its operation process is simple; after coating, it can be peeled off after curing, making it very suitable for large-scale applications in nuclear facilities. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the process for preparing a peelable decontamination material with uranium colorimetric tracing function in an embodiment of the present invention;

[0028] Figure 2 The diagram shows the peelable stain remover coating after the addition of uranyl ions at different times. (a) shows no contaminants, (b) shows contaminants in the uranyl ion standard solution, and (c) shows the colorimetric tracing of each component of the contaminant in the cerium nitrate solution over time. Detailed Implementation

[0029] 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.

[0030] This invention provides a technical solution: a peelable decontamination material with uranium colorimetric tracing function and its preparation method. The material uses polyvinyl alcohol (PVA) as the film-forming matrix, and introduces an amphiphilic block copolymer PEA-b-PAA as a dispersant. This dispersant works synergistically with the colorimetric indicator 2-(5-bromo-2-pyridiniazo)-5-diethylaminophenol (Br-PADAP) to achieve efficient adsorption and visual monitoring of uranium contamination. The preparation steps are as follows: Figure 1 As shown, the preparation process includes the following:

[0031] S1. Preparation of amphiphilic block copolymer dispersant PEA-b-PAA;

[0032] Using S,S,S-trithiodibenzyl carbonate (DBTTC) as the RAFT reagent and azobisisobutyronitrile (AIBN) as the initiator, a one-pot, two-step polymerization reaction was carried out in anhydrous ethanol solvent. First, the EA segment was polymerized, followed by the addition of AA to continue the reaction, controlling the molar ratio of EA to AA between (2:1) and (1:1). After the reaction, the target block copolymer PEA-b-PAA was obtained through purification. Specifically, ethyl acrylate (EA) monomer was first added for the first-stage polymerization to obtain the macromolecular chain transfer agent PEA-CTA; then, acrylic acid monomer (AA) was added for the second-stage polymerization to obtain the PEA-b-PAA amphiphilic block copolymer.

[0033] S,S,S-trithiodibenzyl carbonate (DBTTC): A reaction was carried out using carbon disulfide, sodium hydroxide, and benzyl chloride as raw materials at room temperature for 24 hours in the presence of a phase-transfer catalyst, tetrabutylammonium bromide (TBAB). After the reaction, the solvent was removed by extraction and rotary evaporation, and the product was purified by column chromatography to obtain a pale yellow oily product, S,S,S-trithiodibenzyl carbonate (DBTTC).

[0034] S2. Preparation of indicator dispersion: Dissolve Br-PADAP in an ethanol solution containing PEA-b-PAA and stir thoroughly to obtain the indicator dispersion;

[0035] S3. Preparation of substrate solution: Dissolve the polymer film-forming substrate in deionized water, heat and stir until completely dissolved to obtain the substrate solution;

[0036] Take 8-12 parts of polyvinyl alcohol (PVA, model 1788), add 40-60 parts of deionized water, stir at 90℃ until completely dissolved to form a uniform, transparent, particle-free solution, and keep warm for later use.

[0037] S4. Preparation of peelable decontamination material: Add indicator dispersion and additives to substrate solution, stir and mix evenly, and adjust pH to 8.0-8.5 to obtain the peelable decontamination material with uranium colorimetric tracing function.

[0038] Take 100 parts of the prepared PVA solution and add 4-8 parts of polyvinylpyrrolidone (PVP, molecular weight 40000), 3-5 parts of glycerol, and 0.3-0.5 parts of ethylenediaminetetraacetic acid (EDTA) sequentially. Stir mechanically until homogeneous. Then add 3-6 parts of the synthesized PEA-b-PAA copolymer and 0.001-0.003 parts of Br-PADAP indicator pre-dissolved in an appropriate amount of ethanol, and continue stirring for 30 minutes. Finally, adjust the pH of the system to 8.0-8.5 with ammonia to ensure optimal stability of the colorimetric reaction. Let the resulting mixture stand for 12 hours and measure its viscosity. Depending on the actual construction requirements, an appropriate amount of deionized water can be added to adjust the viscosity to the range of 2000-5000 mPa·s. Store the final product in a sealed container in a cool place, away from light and high temperatures.

[0039] Furthermore, the present invention may optionally add a surfactant to further optimize wettability and film-forming properties. The surfactant may be selected from one or more of sodium dodecyl sulfate (SDS), sodium dodecylbenzene sulfonate (SDBS), or polyoxyethylene ether nonionic surfactants, and the amount added is 0.1 to 0.5 parts.

[0040] Example 1: Preparation of amphiphilic block copolymer PEA-b-PAA (EA:AA = 1.5:1)

[0041] Synthesis of RAFT reagent DBTTC:

[0042] 200 mL of analytical grade carbon disulfide (CS2) and 200 mL of 33% sodium hydroxide (NaOH) aqueous solution were added to a 500 mL flask and stirred at room temperature for 10 minutes. Then, 20 mL of benzyl chloride and 2.30 g of tetrabutylammonium bromide (TBAB) were added. The solution color changed from colorless to pale yellow, and finally to blood red. The reaction was carried out under vigorous stirring for 24 hours. After the reaction was complete, the reaction solution was extracted multiple times with CS2, the organic phases were combined, and CS2 was removed using a rotary evaporator to obtain crude DBTTC. Finally, the crude product was purified by column chromatography (using n-hexane as eluent) to obtain a pale yellow oily liquid, DBTTC.

[0043] Synthesis of PEA-b-PAA (one-pot two-step method):

[0044] Step 1 (Synthesis of PEA macromolecular chain transfer agent): In a 500 mL four-necked flask equipped with a condenser, thermometer, and stirrer, add 24.03 g (0.24 mol) ethyl acrylate (EA), 0.35 g (0.0012 mol) DBTTC, 0.1 g azobisisobutyronitrile (AIBN), and 50 mL anhydrous ethanol. React at 75 °C under nitrogen protection for 12 hours.

[0045] Step 2 (chain extension synthesis of block copolymer): Add 20.66g (0.24mol) of acrylic acid (AA) and 0.05g of AIBN to the above system and continue to react at 75°C for 10 hours.

[0046] Step 3: After the reaction was complete, the product was precipitated in ice-cold n-hexane, filtered, washed three times with cold n-hexane, and dried in a vacuum drying oven at 40°C to constant weight to obtain a white solid product, PEA-b-PAA. GPC analysis showed that its number-average molecular weight (M...) was... n The concentration was 25,300 g / mol, and the molecular weight distribution (PDI) was 1.21. This was determined by proton nuclear magnetic resonance spectroscopy (NMR). 1 According to H NMR calculations, the molar ratio of EA to AA is approximately 1.5:1.

[0047] Example 2: Preparation of a peelable decontamination material with uranium colorimetric tracing function

[0048] Step 1 (Preparation of matrix solution): Weigh 10g of polyvinyl alcohol (PVA-1788) and dissolve it in 90g of deionized water. Stir vigorously in a 90℃ water bath until completely dissolved to obtain a clear and transparent 10wt% PVA solution. Keep it warm for later use.

[0049] Step 2 (Material Composite): Take 100g of the above PVA solution and add 6g of polyvinylpyrrolidone (PVP, Mw=40000), 4g of glycerol, and 0.4g of disodium ethylenediaminetetraacetate (EDTA-2Na) in sequence under mechanical stirring, and stir until completely dissolved and mixed evenly.

[0050] Step 3 (Addition of Functional Components): Weigh 0.002g of Br-PADAP indicator and dissolve it in 5mL of anhydrous ethanol. Then add 4g of the PEA-b-PAA copolymer prepared in Example 1 and gently shake to initially disperse it. Then slowly add this mixture to the matrix solution.

[0051] Step 4 (pH Adjustment and Maturation): After continuous mechanical stirring for 30 minutes, concentrated ammonia was added dropwise to adjust the pH of the system to 8.3. The final product was allowed to stand and mature for 12 hours, and the viscosity was measured to be 3500 mPa·s (25℃). It was then sealed and stored away from light.

[0052] Example 3: Performance Testing of Peelable Decontamination Materials

[0053] The following performance tests were performed on the material prepared in Example 2:

[0054] Decontamination performance: Using simulated radioactive fallout (doped with potassium) as the contaminant, the material was evenly distributed on the surfaces of glass, epoxy resin, and 304 stainless steel substrates (10cm × 10cm). The material from Example 2 was uniformly coated onto the contaminated surface at a coating weight of approximately 200g / m². 2After curing and molding at room temperature, it can be completely peeled off. ICP-OES was used to determine the Kt concentration on the surface before and after wiping with contaminants. + The content was calculated using a formula to determine the cleaning rate. The results showed that the material achieved cleaning rates of 99.52%, 99.62%, and 99.63% on glass, epoxy resin, and 304 stainless steel surfaces, respectively.

[0055] Colorimetric tracer performance: Uranyl nitrate (UO2(NO3)2·6H2O) standard solutions of different concentrations were added to the surface of the cured film, and the color changes were observed. The results are as follows: Figure 2 As shown in the figure, after the uranyl standard solution was added, a color change occurred within 30 seconds, and diffusion was completed within five minutes, achieving a good tracing effect. The color difference value (ΔE) was measured using a colorimeter to determine the sensitivity. The results showed that the material changed from its initial milky white to purplish-red within one minute of contact with uranium contaminants. Using ΔE > 10 as the standard for visible color difference, the calculated minimum detection limit for uranium contamination was 0.81 × 10⁻⁶. -6 mol / cm 2 .

[0056] Specificity: At optimal pH (8.0-8.5), the color change is related to uranyl ions (UO2). 2+ It has good specificity and is less affected by common metal ions.

[0057] Mechanical properties: Standard dumbbell-shaped specimens were fabricated, and their mechanical properties were tested using a universal testing machine. The results showed a tensile strength of 1.85 MPa and an elongation at break of 285%. The peel strength was 0.15 N / mm, indicating that the film could be easily and completely peeled from the substrate surface, and that the film itself had high strength and was not easily torn.

[0058] Example 4: Effect of different proportions

[0059] Repeat the steps of Example 2 by varying the amounts of PEA-b-PAA and Br-PADAP added:

[0060] Sample A: PEA-b-PAA added at 2 wt%, Br-PADAP at 0.001 wt%. Results showed a slight decrease in colorimetric sensitivity, with a detection limit of 1.5 × 10⁻⁶. -6 mol / cm 2 The decontamination rate remains above 98%.

[0061] Sample B: PEA-b-PAA addition was 6 wt%, and Br-PADAP addition was 0.003 wt%. The resulting film had a slightly darker base color but higher color contrast and a larger ΔE. The viscosity increased to 4800 mPa·s, making it more suitable for application on vertical surfaces.

[0062] Comparative Example 1

[0063] Without adding PEA-b-PAA dispersant, 0.002g of Br-PADAP powder was directly added to the PVA matrix, and the remaining steps were exactly the same as in Example 2.

[0064] Results: Br-PADAP dispersed very poorly in the system, exhibiting significant aggregation and precipitation after standing. Visible indicator particles were present in the film after formation, and the color was uneven. The colorimetric reaction was sluggish and uneven, and the detection limit was significantly elevated (>5.0 × 10⁻⁶). - 6 mol / cm 2 ).

[0065] Comparative Example 2

[0066] Without the addition of Br-PADAP indicator, the remaining components are exactly the same as in Example 2.

[0067] Results: The material has good decontamination performance (decontamination rate >99%), but it completely loses its colorimetric tracing function and cannot perform visual monitoring of uranium contamination.

[0068] This invention is particularly applicable to surface decontamination and real-time monitoring of uranium contamination in scenarios such as nuclear facility decommissioning, nuclear accident emergency response, and medical radioactive waste disposal, and has significant practical application value and promising prospects for promotion.

[0069] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0070] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0071] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0072] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0073] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A peelable decontamination material with uranium colorimetric tracing function, characterized in that, The peelable decontamination material with uranium colorimetric tracing function comprises the following components by weight: Polymer film-forming substrate: 100 parts; Colorimetric indicator 2-(5-bromo-2-pyridiniazo)-5-diethylaminophenol Br-PADAP: 0.001–0.003 parts; Amphiphilic block copolymer dispersant: 1-8 parts; The amphiphilic block copolymer dispersant is polyethyl acrylate-block-polyacrylic acid PEA-b-PAA.

2. The peelable decontamination material with uranium colorimetric tracing function according to claim 1, characterized in that: The peelable and decontaminating material with uranium colorimetric tracing function further includes one or more of the following additives: 0.1 to 0.5 parts of masking agent ethylenediaminetetraacetic acid (EDTA); 3-5 parts of plasticizer glycerin.

3. The peelable decontamination material with uranium colorimetric tracing function according to claim 1, characterized in that: The PEA-b-PAA is prepared by reversible addition-fragmentation chain transfer polymerization of ethyl acrylate (EA) and acrylate (AA), with a monomer feed ratio of EA:AA of 1 to 2:

1.

4. The peelable decontamination material with uranium colorimetric tracing function according to claim 1 or 3, characterized in that: The monomer feed ratio of PEA-b-PAA is EA:AA 1.5:

1.

5. The peelable decontamination material with uranium colorimetric tracing function according to claim 1, characterized in that: The amount of the amphiphilic block copolymer dispersant added is 4 parts.

6. The peelable decontamination material with uranium colorimetric tracing function according to claim 1, characterized in that: The polymer film-forming substrate is polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), or a mixture of the two.

7. A method for preparing a peelable decontamination material with uranium colorimetric tracing function according to any one of claims 1-6, characterized in that: Includes the following steps: S1. Preparation of amphiphilic block copolymer dispersant PEA-b-PAA; S2. Preparation of indicator dispersion: Dissolve Br-PADAP in an ethanol solution containing PEA-b-PAA and stir thoroughly to obtain the indicator dispersion; S3. Preparation of substrate solution: Dissolve the polymer film-forming substrate in deionized water, heat and stir until completely dissolved to obtain the substrate solution; S4. Preparation of peelable decontamination material: Add indicator dispersion and additives to substrate solution, stir and mix evenly, and adjust pH to 8.0-8.5 to obtain the peelable decontamination material with uranium colorimetric tracing function.

8. The preparation method according to claim 7, characterized in that: In step S1, the preparation of the amphiphilic block copolymer dispersant PEA-b-PAA includes the following: Using S,S,S-trithiodibenzyl carbonate (DBTTC) as the RAFT reagent and azobisisobutyronitrile (AIBN) as the initiator, ethyl acrylate (EA) monomer was first added to anhydrous ethanol solvent for the first stage of polymerization to obtain the macromolecular chain transfer agent PEA-CTA; then acrylic acid monomer (AA) monomer was added for the second stage of polymerization to obtain the PEA-b-PAA amphiphilic block copolymer.

9. The application of a peelable decontamination material with uranium colorimetric tracing function according to any one of claims 1-6 or a peelable decontamination material with uranium colorimetric tracing function prepared by the preparation method according to any one of claims 7-8 for visual decontamination and tracing of uranium-contaminated surfaces during nuclear facility decommissioning and nuclear accident emergency response.

10. The application according to claim 9, characterized in that: A peelable decontamination material with uranium colorimetric tracing function was uniformly coated onto the surface of a contaminated substrate and cured into a film at room temperature. Upon contact with uranium contaminants, a visible color change occurred within one minute, from an initial milky white to a purplish-red. The detection limit for uranium contamination reached as low as 0.81 × 10⁻⁶. -6 mol / cm 2 The membrane has a tensile strength of up to 1.85 MPa, an elongation at break of up to 285%, and a peel strength of up to 0.15 N / mm, making it easy to peel completely from the substrate surface.

Images