Composite material with fluorescence characteristic and use method thereof

Abstract

The invention relates to the technical field of composite materials, in particular to a composite material with a fluorescence characteristic and a use method thereof, and the composite material comprises a modified fluorescent graphene fiber membrane, resin paint, a diluent and a curing agent; wherein the modified fluorescent graphene fiber membrane is prepared from fluorescent graphene powder, chitosan and polyacrylonitrile through electrostatic spinning; the fluorescence intensity of the fluorescent graphene is greatly improved by utilizing an electrostatic spinning technology, the resin paint is endowed with more excellent fluorescence display capability, nondestructive detection of the service condition of the resin paint coating is realized by utilizing fluorescence characteristics, the corrosion condition of the resin paint coating is more accurately and intuitively mastered, and the service life of the resin paint coating is prolonged. The paint can be widely applied to the aspects of anticorrosive paint, building and concrete structure protection, ocean engineering and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and particularly to a composite material with fluorescence characteristics and a method for using the same. Background Art

[0002] In the field of material protection, traditional resin paints can form a continuous and uniform paint film on the surface of the protected material due to their excellent film-forming properties, providing a good physical barrier for the substrate material. Their excellent adhesion ensures a tight bond between the coating and the substrate, making it difficult to peel off, greatly enhancing the stability of the protection system. At the same time, their good corrosion resistance enables traditional resin paints to effectively resist the erosion of external chemical substances and are widely used in many industrial and civil scenarios, providing a basic guarantee for the long-term stable operation of various equipment and facilities.

[0003] However, traditional resin paints have significant limitations. With the increasingly complex usage environment of materials and the continuous improvement of safety requirements, the problem that it is difficult to achieve real-time status monitoring has gradually emerged. In the actual application process, the coating will inevitably suffer various forms of micro-damage, such as mechanical scratches and tiny pinholes generated at the initial stage of chemical corrosion. Due to the lack of effective real-time monitoring means, these micro-damages cannot be detected in time, let alone early warning. Over time, the micro-damages will continue to develop and expand, gradually weakening the protection performance of the coating, and ultimately may lead to serious problems such as corrosion and failure of the protected material, posing a great threat to the use safety. Especially in fields such as aerospace, ocean engineering, and high-end equipment manufacturing where extremely high requirements are placed on the reliability of materials, this defect of traditional resin paints will cause losses.

[0004] The information disclosed in this background art section is only intended to deepen the understanding of the overall background art of the present invention, and should not be regarded as an admission or any form of suggestion that this information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0005] The first object of the present invention is to provide a composite material with fluorescence characteristics, which uses electrospinning technology to greatly enhance the fluorescence intensity of fluorescent graphene, endows the resin paint with more excellent fluorescence display ability, and then uses the fluorescence characteristics to achieve non-destructive detection of the service condition of the resin paint coating, more accurately and intuitively controlling the corrosion condition of the resin paint coating, and can be widely used in anti-corrosion coatings, building and concrete structure protection, ocean engineering, etc.

[0006] The above technical object of the present invention is achieved through the following technical solutions:

[0007] A composite material with fluorescence characteristics, comprising a modified fluorescent graphene fiber membrane, a resin paint, a diluent, and a curing agent;

[0008] Among them, the modified fluorescent graphene fiber membrane is prepared by electrospinning of fluorescent graphene powder, chitosan and polyacrylonitrile;

[0009] Due to particle aggregation of the fluorescent graphene powder, some fluorescence may be absorbed or undergo non-radiative transitions. The fiber structure prepared by electrospinning technology can prevent the excessive stacking of fluorescent graphene sheets, avoid the aggregation effect in the fluorescent graphene powder, thereby reducing fluorescence quenching and enhancing the overall fluorescence effect; and after electrospinning, the fluorescent graphene powder is dispersed in the fiber, and the overall specific surface area of the fiber membrane is much higher than that of the individual fluorescent graphene powder, improving the fluorescence emission efficiency; at the same time, the optical waveguide effect and internal filtering effect of the fiber membrane reduce the light energy loss, making the fluorescence signal stronger and more stable. These structures and optical properties work together to make the fluorescence intensity of the fiber membrane reach 170 times that of the fluorescent graphene powder; the cross-linking effect between the fluorescent graphene and chitosan further improves the mechanical strength of the fiber membrane, and at the same time, the excellent mechanical properties and electrical conductivity of the graphene fiber membrane improve the impact resistance and corrosion resistance of the overall coating, providing multiple performance guarantees for the intelligent protective coating.

[0010] As a preferred embodiment of the present invention, the curing agent is polyamide. Calculated by mass percentage, the dosage of the curing agent is 15-25% of the mass of the resin paint;

[0011] Preferably, the curing agent is polyamide 593 type. Polyamide 593 type has excellent chemical reaction activity. After fully reacting with the resin paint matrix, it can significantly improve the curing speed, cross-linking density and mechanical strength of the coating. The addition amount of 15-25% can provide a stable curing environment for the composite system, making the coating show excellent durability, wear resistance and adhesion after curing, enhancing the bonding effect between the modified fluorescent graphene fiber membrane and the resin paint. In addition, the flexibility of the polyamide curing agent helps to slow down the curing shrinkage of the resin, improve the crack resistance of the composite material, and ensure the stability of the film layer.

[0012] As a preferred embodiment of the present invention, the diluent is butyl acetate. Calculated by mass percentage, the dosage of the diluent is 5-15% of the mass of the resin paint; Butyl acetate, as an efficient diluent, is mainly used to reduce the resin viscosity, improve the dispersibility and optimize the film-forming quality during the composite process. The addition amount of 5-15% can enhance the uniform distribution of the modified fluorescent graphene fiber membrane in the resin paint, improve the interfacial compatibility, and ensure the uniformity of the coating during the stirring and coating processes; at the same time, its moderate evaporation rate can effectively control the drying process of the coating, reduce bubbles and defects, ensure the surface smoothness, and improve the uniformity of the fluorescence effect.

[0013] As a preferred embodiment of the present invention, the preparation method of the modified fluorescent graphene fiber membrane includes:

[0014] S1 Weigh the fluorescent graphene powder, chitosan, and polyacrylonitrile according to the mass ratio;

[0015] S2 Dissolve the fluorescent graphene powder and chitosan in absolute ethanol. Chitosan has abundant amino and hydroxyl groups, which can form hydrogen bonds and electrostatic interactions with the fluorescent graphene, improving its stability in the solution and preventing subsequent sedimentation or aggregation. The prior mixing of chitosan and fluorescent graphene ensures their good fusion, creating a uniform solution environment for the subsequent addition of polyacrylonitrile;

[0016] Then add polyacrylonitrile to obtain a solution. More specifically, when adding polyacrylonitrile, it should be added slowly. Slowly adding can avoid the aggregation of PAN chains caused by too high local concentration, thereby improving the uniformity of the spinning solution. Such an operation method helps to optimize the experimental process and lays a foundation for obtaining high-quality composite materials;

[0017] S3 Heat and stir the solution to obtain a spinning solution. More specifically, before heating the solution, ultrasonicate the solution for a period of time. The purpose of this setting is that before the water bath reaction, ultrasonic treatment of the mixture can prevent the massive stacking of fluorescent graphene, avoid the weakening of the fluorescent signal, and improve the fluorescent performance of the composite material. The heating method is a water bath at a temperature of 50 - 70 °C, and the stirring time is 24 h. During the water bath reaction, appropriate stirring and heating contribute to the interaction between the fluorescent graphene, chitosan, and polyacrylonitrile, improving the mechanical properties of the composite fiber;

[0018] S4 Use the spinning solution for electrospinning;

[0019] The present invention uses electrospinning technology to uniformly disperse the fluorescent graphene powder in the fiber. The good dispersion state effectively prevents the aggregation of the fluorescent graphene, reduces the fluorescence quenching caused by aggregation, and thus greatly improves the overall fluorescence intensity. As a natural polymer, chitosan not only has good film-forming properties and biocompatibility but also can form a large number of hydrogen bonds and other intermolecular interactions with polyacrylonitrile and fluorescent graphene. This cross-linking effect improves the interfacial adhesion between the components, thereby enhancing the overall mechanical strength and durability of the composite material. And polyacrylonitrile provides a tough matrix, while chitosan enhances the structural integrity of the fiber membrane through chemical cross-linking. At the same time, the good dispersion state avoids the aggregation of the fluorescent graphene, enabling the fluorescent signal to be greatly amplified. Such multiple synergistic effects ultimately make the composite fiber membrane not only significantly improved in optical performance but also its mechanical properties improved due to the addition of chitosan.

[0020] As a preferred embodiment of the present invention, the mass ratio of the fluorescent graphene powder, chitosan, and polyacrylonitrile is 2-4:3:10. A relatively small content of fluorescent graphene will not significantly change the rheological and film-forming properties of polyacrylonitrile and chitosan, thus ensuring the continuity and mechanical strength of the fibers. At the same time, a relatively small content of fluorescent graphene ensures that it can be evenly dispersed in the fiber structure, preventing fluorescence quenching caused by excessive aggregation, and thus ensuring that the overall composite material has higher and more uniform fluorescence intensity.

[0021] As a preferred embodiment of the present invention, the parameters of electrospinning are as follows: the distance between the spinning needle and the aluminum foil paper is 10-12 cm, the spinning speed is 0.5-1.5 ml / h, and the spinning voltage is 15-23 kv. The above parameters are used to ensure that the fibers have enough time to complete solvent evaporation before reaching the collector to form continuous fibers. By providing sufficient electrostatic force, the solution is ejected from the needle, while preventing the solution from dripping or forming an unstable jet due to too low voltage. An appropriate flow rate ensures the stability of the jet and obtains uniform nanofibers.

[0022] As a preferred embodiment of the present invention, the fluorescent graphene powder is prepared from graphene oxide, rare earth nitrate, and organic ligand in a water bath reaction.

[0023] More specifically, the preparation method includes: dissolving rare earth nitrate in absolute ethanol to obtain solution A, and dissolving graphene oxide and organic ligand together in another portion of absolute ethanol to obtain solution B; pouring solution B into solution A and mixing evenly, after ultrasonic treatment for a period of time, subjecting the mixed solution to a water bath reaction and centrifuging, then washing the obtained fluorescent graphene to remove the unloaded rare earth complexes, and subsequently drying it in an oven.

[0024] Organic ligands usually have strong ultraviolet or visible light absorption ability. When the ligand absorbs photons, its electrons will transition from the ground state to the excited state. The excited organic molecules will undergo internal conversion and quickly change from the excited singlet state (S1) to the lower-energy triplet state (T1). Since the triplet energy level is usually relatively stable and has a long lifetime, this provides sufficient time for subsequent energy transfer. When the triplet energy level of the organic ligand matches the acceptor energy level of the rare earth ion (Tb3+), the organic ligand can transfer the absorbed energy to the rare earth ion by a non-radiative method. This process is called the "antenna effect", enabling the rare earth ion to emit light under the condition of weak self-absorption ability. For the rare earth ion that receives the energy, its 4f electrons undergo a transition and return from the excited state to the ground state, releasing fluorescence with characteristic narrow bandwidth and high color purity. Relying on the sensitivity of the coordination field environment of rare earth ions to corrosive media, using rare earth ions as fluorescent probes, the damage of the resin paint coating is reflected from the perspective of the coordination field structure.

[0025] As a preferred embodiment of the present invention, the weight percentage of the modified fluorescent graphene fiber membrane to the resin paint is 1:50 - 150;

[0026] The ratio of 1:50 - 150 achieves a multi-performance balance of the intelligent protective coating by optimizing the dispersibility, mechanical contribution, and cost-effectiveness of the modified fluorescent graphene fiber membrane, especially taking into account the real-time monitoring ability and long-term protection requirements in the field of high reliability.

[0027] The second object of the present invention is to provide a method for using a composite material with fluorescence characteristics, which does not require complex equipment and processes, is easy to implement in actual production, reduces the use difficulty and cost, and can accurately and intuitively indicate the lifespan of the coating.

[0028] The above technical objects of the present invention are achieved through the following technical solutions:

[0029] A method for using a composite material with fluorescence characteristics, comprising:

[0030] Mix the resin paint and the diluent evenly, and then add the curing agent and stir to obtain a resin paint mixture; more specifically, the whole process is carried out in a water bath while heating and stirring to make the three mix evenly;

[0031] First, cut the modified fluorescent graphene fiber membrane into the same size as the substrate, lay it flat on the surface of the substrate, and then evenly apply the resin paint mixture;

[0032] When the environment where the coating is located causes it to corrode, the change in the matrix structure will be transmitted to the modified fluorescent graphene fiber membrane, causing it to break due to factors such as uneven stress. Since the modified fluorescent graphene fiber membrane has unique fluorescence characteristics, the fluorescence signal at the break will change accordingly. Based on this, the degree of corrosion can be intuitively and accurately judged by detecting the fluorescence change; the method of use does not require professional and complex equipment, greatly reducing the operation difficulty and facilitating popularization and application in all aspects of actual production. Whether it is large-scale industrial production or small-scale project construction, it can be easily handled, effectively taking into account the function realization and use convenience;

[0033] Conduct a correlation analysis on the fluorescence parameters and the degree of corrosion of the test piece with the composite material to obtain a correlation index;

[0034] More specifically, the fluorescence parameters are the fluorescence spectra obtained after the coating formed by the present invention is excited by ultraviolet light of 300 - 400 nm, and the rare earth ions in the rare earth complex (such as Eu3+, Tb 3+, etc.) is a 4f electronic configuration in its ground and excited states. Since the 4f electrons are in the inner orbital and lack the effective shielding of the outermost s orbital, the corrosive medium changes the electron cloud distribution of the rare earth ions, affecting the local symmetry and electronic environment of the rare earth ions. Therefore, the sensitivity of the rare earth ion coordination field environment to the corrosive medium is studied. Using rare earth ions as fluorescent probes, the damage of the resin paint coating is reflected from the perspective of the coordination field structure.

[0035] Coatings with stronger fluorescence properties enhance the sensitivity of the detection system, can provide more stable fluorescence parameters in quantitative analysis, make correlation index analysis more accurate, and the color of strong fluorescent coatings usually has a brighter initial state, so during the corrosion process, due to changes in chemical composition and structure, the color coordinates of the coating will also change more obviously;

[0036] The fluorescence parameters of the composite materials under different corrosion degrees are marked in CIE coordinates, and the corrosion degree of the coating to be tested is determined according to the correlation index and the position of the CIE coordinate point.

[0037] The preparation method of the present invention is adopted to prepare a modified graphene fiber membrane reinforced resin paint composite material with fluorescent characteristics. Under ultraviolet light excitation, the resin emits characteristic light. By virtue of the sensitivity of the rare earth ion coordination field environment to the corrosive medium, the rare earth ions are used as fluorescent probes, and the fluorescence intensity of the modified fluorescent graphene fiber membrane resin paint composite coating and the degree of corrosion are correlated. The fluorescence parameters of the fiber membrane resin paint composite coating under different corrosion degrees are marked in CIE coordinates. The degree of corrosion of the coating to be tested can be judged according to the correlation index and the position of the CIE coordinate point, and its service life can be accurately and intuitively indicated, thereby opening up innovative application prospects for the modified fluorescent graphene fiber membrane resin paint composite coating.

[0038] As a preferred embodiment of the present invention, a method for obtaining a correlation index includes:

[0039] The corrosion degree was taken as the independent variable and the fluorescence intensity as the dependent variable. The fluorescence parameters were linearly fitted with the corrosion degree to obtain the correlation index.

[0040] The correlation index reflects the linear relationship between the corrosion degree and the fluorescence attenuation. 2When the value is close to 1, it indicates that the attenuation of fluorescence intensity with the degree of corrosion is very stable and shows a highly linear relationship, which usually indicates that the chemical structure and physical state inside the coating are degrading in a uniform manner; at the same time, the color coordinates characterize the color change of the coating. With the aggravation of corrosion, the coating will show phenomena such as color drift and fluorescence quenching, and the significant shift of the color coordinates can reflect the change of the chemical components of the coating; judging the corrosion degree of the resin paint coating according to the degree of approach of the correlation index of the coating to be measured to 1 and the position of the color coordinates can quantitatively evaluate the degradation status of the resin paint coating in the corrosive environment and provide a reliable basis for the evaluation and improvement of the corrosion resistance performance of the coating.

[0041] The beneficial effects of the present invention compared with the prior art are as follows:

[0042] 1) By electrospinning the fluorescent graphene powder into fibers, the dispersibility of graphene can be improved, the fluorescence quenching effect can be reduced, and the fluorescence intensity can be increased through the optical enhancement effect of the fiber structure. After electrospinning, the fluorescent graphene powder is dispersed in the fibers, and the overall specific surface area of the fiber membrane is much higher than that of the individual fluorescent graphene powder, improving the fluorescence emission efficiency. At the same time, the optical waveguide effect and inner filter effect of the fiber membrane reduce the light energy loss, making the fluorescence signal stronger and more stable. The synergistic effect of these structures and optical properties makes the fluorescence intensity of the fiber membrane reach 170 times that of the fluorescent graphene powder, providing new possibilities for the development of high-performance fluorescent materials;

[0043] 2) Using the preparation method of the present invention to prepare a modified graphene fiber membrane reinforced resin paint composite material with fluorescence characteristics, under ultraviolet light excitation, the resin emits characteristic light. Relying on the sensitivity of the coordination field environment of rare earth ions to corrosive media, using rare earth ions as fluorescence probes, analyzing the correlation between the fluorescence intensity of the modified fluorescent graphene fiber membrane resin paint composite coating and the degree of corrosion, and marking the fluorescence parameters of the fiber membrane resin paint composite coating under different corrosion degrees in the CIE coordinates. Judging the corrosion degree of the coating to be measured according to the correlation index and the position of the CIE coordinate point can accurately and intuitively indicate its service life, opening up an innovative application prospect for the modified fluorescent graphene fiber membrane resin paint composite coating. Brief Description of the Drawings

[0044] Figure 1 is the microscopic morphology diagram of the composite material of the present invention under scanning electron microscopy;

[0045] Figure 2 is the water contact angle of the modified fluorescent graphene fiber membrane;

[0046] Figure 3 is the fluorescence spectrum diagram of the fluorescence intensities of the modified fluorescent graphene fiber membrane and the fluorescent graphene powder;

[0047] Figure 4It is the EIS (Nyquist) diagram of resin paint, fluorescent graphene fiber membrane composite resin, and modified fluorescent graphene fiber membrane composite resin;

[0048] Figure 5 It is the coupling relationship diagram between the quenching constant and the fluorescence intensity of the composite material of the present invention as it gradually increases with the corrosion time;

[0049] Figure 6 It is the CIE coordinate diagram of the composite material of the present invention under different service durations;

[0050] Figure 7 It is the flow chart of the preparation and use method of the composite material of the present invention;

[0051] Figure 8 It is the scanning electron microscope diagram of the fluorescent graphene fiber membrane composite resin prepared in Comparative Example 2. Specific Embodiments

[0052] To make the above objects, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings of the specification.

[0053] Many specific details are set forth in the following description in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0054] Secondly, the so-called "embodiment" herein refers to specific features, structures, or characteristics that can be included in at least one implementation manner of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that excludes other embodiments.

[0055] Table 1 shows the material sources in the specific embodiments:

[0056] Component Commercially available source Resin paint Guangzhou Suixin Chemical Industry Co., Ltd. Polyacrylonitrile Shanghai National Pharmaceutical Group Chemical Reagent Co., Ltd. Chitosan Shanghai Macklin Biochemical Co., Ltd. Graphene Graphene Gold Medal Mall, Graphene of Harbin Institute of Technology Rare earth nitrate Beijing Huawei RuiKe Chemical Technology Co., Ltd. 1,10-Phenanthroline Shanghai Zhanyun Chemical Industry Co., Ltd. Polyamide 593 curing agent Kunshan Jiulimei Electronic Materials Co., Ltd. Butyl acetate Aladdin Biochemical Technology Co., Ltd.

[0057] Embodiment:

[0058] This embodiment provides a composite material with fluorescence characteristics and its use method;

[0059] A composite material with fluorescence characteristics, including a modified fluorescent graphene fiber membrane, resin paint, polyamide 593, and butyl acetate; wherein, the mass ratio of the modified fluorescent graphene fiber membrane to the resin paint is 1:86, the addition amount of polyamide 593 is 20% of the weight of the resin paint, and the addition amount of butyl acetate is 10% of the weight of the resin paint;

[0060] Among them, the preparation method of the fluorescent graphene powder is as follows:

[0061] Dissolve rare earth nitrate in absolute ethanol to obtain solution A, and dissolve graphene oxide and organic ligand together in another portion of absolute ethanol to obtain solution B; pour solution B into solution A, mix evenly, after ultrasonic treatment for a period of time, subject the mixed solution to a water bath reaction and centrifuge, then wash the obtained fluorescent graphene to remove the unloaded rare earth complexes, and then put it into an oven to dry to obtain the fluorescent graphene powder;

[0062] The preparation method of the modified fluorescent graphene fiber membrane is as follows:

[0063] S1 Weigh the fluorescent graphene powder, chitosan and polyacrylonitrile according to the mass ratio of 3:3:10;

[0064] S2 Dissolve the fluorescent graphene powder and chitosan together in absolute ethanol to obtain a solution, and slowly add and dissolve polyacrylonitrile into the solution;

[0065] S3 After ultrasonic treatment of the solution for a period of time, obtain a spinning solution through a water bath reaction, the temperature of the water bath is 50 - 70 °C, and the stirring time is 24 h;

[0066] S4 Collect the spinning solution into a syringe equipped with a No. 21 needle for electrospinning. During electrospinning, the distance between the spinning needle and the aluminum foil paper is 10 - 12 cm, the spinning speed is 0.5 - 1.5 ml / h, and the spinning voltage is 15 - 23 kv;

[0067] A method for using a composite material with fluorescence characteristics includes:

[0068] Q1 Mix the resin paint and polyamide 593 type evenly, and then add butyl acetate and stir to obtain a resin paint mixture;

[0069] Q2 First cut the modified fluorescent graphene fiber membrane into the same size as the substrate, lay it flat on the surface of the substrate, and then evenly apply the resin paint mixture to obtain a modified fluorescent graphene fiber membrane composite resin;

[0070] Test the modified fluorescent graphene fiber membrane and the modified fluorescent graphene fiber membrane composite resin prepared by the above method, Figure 1 This is the microscopic morphology of the composite material of the present invention under a scanning electron microscope, and the fiber structure is uniform; Figure 2 This is the water contact angle of the modified fluorescent graphene fiber membrane. It is observed that the contact angle is 131°, and the modified fluorescent graphene fiber membrane shows hydrophobicity; thus, it can be seen that the modified fluorescent graphene fiber membrane can be used to block the penetration of oxygen and water molecules and improve the corrosion prevention ability;

[0071] Test the modified fluorescent graphene fiber membrane and the fluorescent graphene powder prepared by the above method,Figure 3 This is the fluorescence spectrum diagram of the modified fluorescent graphene fiber membrane and the fluorescent intensity of the fluorescent graphene powder. The modified fluorescent graphene fiber membrane generated by the electrospinning technique increases the fluorescent intensity of the fluorescent graphene powder by nearly 170 times.

[0072] Figure 4 Shown are the EIS (Nyquist) pictures of the resin paint and the composite resin of the modified fluorescent graphene fiber membrane. The composite resin of the modified fluorescent graphene fiber membrane shows the largest capacitive arc radius, which has a positive effect on the inhibition of corrosion and delays the occurrence of corrosion.

[0073] Dry the substrate with the above-mentioned composite resin of the modified fluorescent graphene fiber membrane in an oven to accelerate curing and obtain the test piece to be measured.

[0074] R1 Measure the uncorroded test piece in a dark room and test the fluorescence parameters of the resin paint coating under the excitation of ultraviolet light with a wavelength of 304 nm.

[0075] R2 Mark the fluorescence parameters on the CIE coordinate diagram and record them as the complete coating points (0 h). Normalization should be carried out before calibration in the CIE coordinates.

[0076] R3 Use the test methods of step R1 and step R2 to test the test pieces that have served for 2 h, 6 h, and 24 h in the salt spray corrosion to be measured, and mark their fluorescence parameters on the CIE coordinates in step S3. Figure 7 This is the CIE coordinate diagram of the resin paint coating with fluorescence characteristics at different service durations. This result provides a solid foundation for further studying the relationship between the corrosion process and the fluorescence characteristics.

[0077] R4 Take the corrosion degree as the independent variable and the fluorescence intensity as the dependent variable, and perform linear fitting on the fluorescence parameters and the corrosion degree to obtain the correlation index. Figure 6 This is the coupling relationship between the quenching constant and the fluorescence intensity after the modified graphene fiber membrane reinforced resin paint composite material with fluorescence characteristics gradually increases with the corrosion time. R 2 = 0.96 reflects that there is a very strong linear correlation between the quenching constant and the corrosion time, indicating that the influence of the corrosion time on the quenching constant is significant.

[0078] R5 The coating with stronger fluorescence performance enhances the sensitivity of the detection system, can provide more stable fluorescence parameters in quantitative analysis, makes the correlation index analysis more accurate, and the color of the strong fluorescence coating usually has a more distinct initial state. Therefore, during the corrosion process, due to the changes in chemical composition and structure, the change of the coating color coordinates will also be more obvious. The correlation index reflects the linear relationship between the corrosion degree and the fluorescence decay. When R 2When the value is close to 1, it indicates that the attenuation of fluorescence intensity with the degree of corrosion is very stable and shows a highly linear relationship, which usually indicates that the chemical structure and physical state inside the coating are degrading in a uniform manner. At the same time, the color coordinates characterize the color change of the coating. As the corrosion intensifies, the coating will exhibit phenomena such as color drift and fluorescence quenching. The significant shift of the color coordinates can reflect the change of the chemical components of the coating. Judging the degree of corrosion of the resin paint coating according to the degree of approximation of the correlation index of the coating to be measured to 1 and the position of the color coordinates can quantitatively evaluate the degradation status of the resin paint coating in the corrosive environment and provide a reliable basis for the evaluation and improvement of the corrosion resistance performance of the coating.

[0079] Comparative Example 1:

[0080] This comparative example provides a composite material with fluorescence characteristics and its usage method;

[0081] A composite material with fluorescence characteristics, including a modified fluorescent graphene fiber membrane, resin paint, polyamide 593 type, and butyl acetate; the dosage is the same as that in the examples;

[0082] The preparation method of the fluorescent graphene powder is the same as that in the examples;

[0083] The preparation method of the fluorescent graphene fiber membrane is as follows:

[0084] S1 Weigh the fluorescent graphene powder and polyacrylonitrile according to a mass ratio of 3:10 (lacking chitosan compared to the examples);

[0085] S2 Dissolve the fluorescent graphene powder in absolute ethanol to obtain a solution, and slowly add and dissolve polyacrylonitrile into the solution;

[0086] S3 After ultrasonicating the solution for a period of time, obtain a spinning solution through a water bath reaction. The temperature of the water bath is 50 - 70 °C, and the stirring time is 24 h;

[0087] S4 Collect the spinning solution into a syringe equipped with a No. 21 needle for electrospinning. During electrospinning, the distance between the spinning needle and the aluminum foil paper is 10 - 12 cm, the spinning speed is 0.5 - 1.5 ml / h, and the spinning voltage is 15 - 23 kv.

[0088] A usage method of a composite material with fluorescence characteristics, including:

[0089] Q1 Mix the resin paint and polyamide 593 type evenly, and then add butyl acetate for stirring to obtain a resin paint mixture;

[0090] Q2 Cut the fluorescent graphene fiber membrane into the same size as the substrate, lay it flat on the surface of the substrate, and then evenly apply the resin paint mixture to prepare a fluorescent graphene fiber membrane composite resin.

[0091] Figure 4 The EIS (Nyquist) images of the fluorescent graphene fiber membrane composite resin are shown. Compared with the pure resin coating, although it shows a positive effect on corrosion inhibition, its corrosion protection performance is not as good as that of the modified fluorescent graphene fiber membrane.

[0092] Comparative Example 2:

[0093] This comparative example provides a composite material with fluorescence characteristics and its usage method;

[0094] A composite material with fluorescence characteristics, including a modified fluorescent graphene fiber membrane, resin paint, polyamide 593, and butyl acetate;

[0095] The preparation method of the fluorescent graphene powder is the same as that in the example;

[0096] The preparation method of the fluorescent graphene fiber membrane is as follows:

[0097] S1 Weigh the fluorescent graphene powder, chitosan, and polyacrylonitrile according to a mass ratio of 3:9:10 (the amount of chitosan is increased compared to the example);

[0098] S2 Dissolve the fluorescent graphene and chitosan together in absolute ethanol to obtain a solution, and slowly add and dissolve the polyacrylonitrile into the solution;

[0099] S3 After ultrasonicating the solution for a period of time, obtain a spinning solution through a water bath reaction. The temperature of the water bath is 50 - 70 °C, and the stirring time is 24 h;

[0100] S4 Collect the spinning solution into a syringe equipped with a No. 21 needle for electrospinning. During electrospinning, the distance between the spinning needle and the aluminum foil paper is 10 - 12 cm, the spinning speed is 0.5 - 1.5 ml / h, and the spinning voltage is 15 - 23 kv.

[0101] A usage method of a composite material with fluorescence characteristics includes:

[0102] Q1 Mix the resin paint and polyamide 593 evenly, and then add butyl acetate and stir to obtain a resin paint mixture;

[0103] Q2 Cut the fluorescent graphene fiber membrane into the same size as the substrate, lay it flat on the surface of the substrate, and then evenly apply the resin paint mixture to prepare the fluorescent graphene fiber membrane composite resin.

[0104] Figure 2The scanning electron microscope image of the fluorescent graphene fiber membrane composite resin prepared by weighing fluorescent graphene powder, chitosan and polyacrylonitrile in a mass ratio of 3:9:10 is shown. The figure shows that the fiber thickness is uneven. The specific surface area of the fine fiber region is large and it combines well with the resin, while the thick fiber region may lead to a decrease in the interfacial bonding force and affect the durability of the coating. In addition, the unevenness of the fiber thickness and distribution will lead to uneven fluorescence response, affecting the accuracy and repeatability of detection.

[0105] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A composite material having fluorescent properties, characterized in that: It includes modified fluorescent graphene fiber membrane, resin paint, diluent and curing agent; The modified fluorescent graphene fiber membrane is made of fluorescent graphene powder, chitosan and polyacrylonitrile by electrostatic spinning.

2. The composite material having fluorescent properties according to claim 1, characterized in that: The curing agent is polyamide, and the curing agent dosage is 15-25% of the mass of the resin paint calculated by mass percentage.

3. The composite material with fluorescent properties according to claim 1, characterized in that: The diluent is butyl acetate, and the amount of the diluent is 5-15% of the mass of the resin paint calculated by mass percentage.

4. The composite material with fluorescent properties according to claim 1, characterized in that: The method for preparing the modified fluorescent graphene fiber membrane comprises: S1 weighs fluorescent graphene powder, chitosan and polyacrylonitrile according to the mass ratio; S2: dissolving the fluorescent graphene powder and the chitosan in anhydrous ethanol, and then adding the polyacrylonitrile to obtain a solution; S3, heating and stirring the solution to obtain a spinning solution; S4. Perform electrospinning using the spinning solution.

5. The composite material with fluorescent properties according to claim 4, characterized in that: The mass ratio of the fluorescent graphene powder, chitosan and polyacrylonitrile is 2-4:3:

10.

6. The composite material having fluorescent properties according to claim 4, characterized in that: The parameters of the electrostatic spinning are: the distance between the spinning needle and the aluminum film paper is 10-12 cm, the spinning speed is 0.5-1.5 ml / h, and the spinning voltage is 15-23 kv.

7. The composite material having fluorescent properties according to claim 1, characterized in that: The fluorescent graphene powder is prepared by reacting graphene oxide, rare earth nitrate and organic ligand in a water bath.

8. The composite material having fluorescent properties according to claim 1, characterized in that: The weight percentage of the modified fluorescent graphene fiber membrane to the resin paint is 1:50-150.

9. The method for using the composite material with fluorescent properties as claimed in claims 1 to 8, characterized in that: include: The resin paint and the diluent are mixed evenly, and then the curing agent is added and stirred to obtain a resin paint mixed liquid; Cutting the modified fluorescent graphene fiber membrane into the same size as the substrate, spreading it on the surface of the substrate, and then evenly applying the resin paint mixture; Performing correlation analysis on the fluorescence parameters of the test piece with the composite material and the corrosion degree to obtain a correlation index; The fluorescence parameters of the composite material under different corrosion degrees are marked in CIE coordinates, and the corrosion degree of the coating to be tested is determined according to the correlation index and the position of the CIE coordinate point.

10. The method for using the composite material having fluorescent properties according to claim 9, characterized in that: The method for obtaining the correlation index comprises: The corrosion degree was taken as the independent variable and the fluorescence intensity as the dependent variable. The fluorescence parameters were linearly fitted with the corrosion degree to obtain the correlation index.

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