Long-afterglow room-temperature phosphorescent silk as well as preparation method and application thereof

Abstract

The invention relates to long-afterglow room-temperature phosphorescent silk as well as a preparation method and application thereof. The preparation method comprises the following steps: soaking silk in a reaction system of an aromatic phenolic compound containing a fused ring or linked ring structure and formaldehyde, reacting at 25-95 DEG C for 1-24 hours, taking out the silk after the reaction, cleaning and drying to obtain the long-afterglow room-temperature phosphorescent silk. On the basis of a Mannich reaction mechanism, an aromatic phenolic compound containing a fused ring or linked ring structure is grafted to the surface of silk, so that the silk has excellent long-afterglow room-temperature phosphorescence performance, and the afterglow duration is more than 2 seconds and can reach 7.3 seconds at most. The long-afterglow room-temperature phosphorescence material has excellent long-afterglow room-temperature phosphorescence characteristics at three excitation wavelengths of 254 nm, 302 nm and 365 nm, and the phosphorescence color and afterglow time can be regulated and controlled according to the types of reactants. The long-afterglow room-temperature phosphorescent silk can be used in the fields of anti-counterfeiting, information encryption and the like.

Description

Technical Field

[0001] The present invention belongs to the field of photoluminescence and textile technology, and more specifically, relates to a long-afterglow room-temperature phosphorescent silk and a preparation method and application thereof. Background Art

[0002] Long afterglow materials generally refer to luminescent materials with a luminescence lifetime greater than 0.1s after the radiation or excitation light source is removed at room temperature. They have great potential in information encryption, bioimaging and sensing. Traditional long afterglow materials are mainly doped with transition metal inorganic compounds, but this method is dependent on metal resources and also produces heavy metal pollution. Therefore, pure organic room temperature phosphorescent materials have been widely studied due to their advantages of low toxicity, low cost and high flexibility. Currently, most organic room temperature phosphorescent materials are often designed as organic crystals, supramolecular structures or metal organic frameworks. However, the preparation process of these materials is complex, the formability and processability are poor, and the lack of flexibility seriously limits their practical application.

[0003] Silk, a natural biopolymer composed of proteins, is smooth, soft, breathable, warm, and hygroscopic. It is often used in high-end clothing and artistic creations. Currently, there are few reports on silk's room-temperature phosphorescence. The development of organic room-temperature phosphorescent materials generally follows two core mechanisms: promoting intersystem crossing through intramolecular charge transfer and creating a rigid environment to inhibit non-radiative transitions. While the intrinsic β-pleated structure of natural silk protein provides a rigid framework, its overly ordered arrangement hinders the effective separation of non-radiative transitions, resulting in a significant reduction in the phosphorescence quantum yield. Unmodified silk protein only exhibits weak phosphorescence at liquid nitrogen temperatures, making it difficult to meet the requirements for room-temperature phosphorescence that is visible to the naked eye.

[0004] Doping nanoparticles such as quantum dots with metal inorganic salts is a common method for preparing biomass polymer room-temperature phosphorescent materials. For example, patent document CN 113621262 A discloses a polysaccharide-based long-lasting glow material and its applications. This long-lasting glow material is made from polysaccharides such as cellulose, chitosan, and oligosaccharides. Sodium bromide, sodium chloride, magnesium bromide, and magnesium chloride are doped into the cellulose and then dehydrated to produce a phosphorescent material that can last for more than one second. The metal ions in this polysaccharide-based long-lasting glow material can generate Coulombic forces, overcoming the electrostatic repulsion between the lone pairs of electrons in the polysaccharide hydroxyl groups and enhancing the aggregation of functional groups containing lone pairs of electrons, such as hydroxyl groups, thereby enhancing cluster luminescence and long-lasting luminescence. However, due to the lack of chemical bonds, the inorganic salts in this long-lasting glow room-temperature phosphorescent material are easily washed away during the washing process, thereby losing the long-lasting room-temperature phosphorescent function. Literature (Large-Scale Preparation for Multicolour Stimulus-Responsive Room-TemperaturePhosphorescence Paper Via Cellulose Heterogeneous Reaction.AdvancedMaterials, 2023, 35, 2305126) introduces the grafting of polyphenyl ring boronic acid compounds onto cellulose, and through the reaction of boric acid with two connected hydroxyl groups, a cellulose-based material with long afterglow room temperature phosphorescence is obtained. In addition, by changing the degree of conjugation of the boric acid compound, the regulation of the phosphorescence color can also be achieved. However, the surface chemical structure of silk is quite different from that of polysaccharide, containing abundant peptide bonds and uncondensed amino groups, so the existing method is not suitable for the modification of silk. Summary of the Invention

[0005] In order to overcome the defects of the prior art, the present invention provides a method for preparing long-lasting room-temperature phosphorescent silk.

[0006] Another object of the present invention is to provide a long-lasting room-temperature phosphorescent silk;

[0007] Another object of the present invention is to provide an application of long-lasting room-temperature phosphorescent silk.

[0008] In order to solve the above technical problems, the technical solutions of the present invention are as follows:

[0009] A method for preparing long-lasting room-temperature phosphorescent silk comprises the following steps:

[0010] The silk is immersed in the reaction system for reaction, and after the reaction, the silk is taken out, washed, and dried to obtain the long-lasting room-temperature phosphorescent silk;

[0011] The reaction system comprises a solvent, an aromatic phenol compound with a condensed ring or linked ring structure, and an aldehyde;

[0012] The molar amount of the aldehyde is 0.1 to 4 times that of the aromatic phenol compound with a condensed ring or linked ring structure.

[0013] In the present invention, the duration of the afterglow of long-afterglow room-temperature phosphorescent silk is affected by the structure of the aromatic phenol compounds with condensed or linked ring structures and the rigid network structure of the silk matrix. The present invention innovatively utilizes the amino groups and aldehydes on the surface of silk to react with the active hydrogen sites on the phenol structure of the aromatic phenol compounds with condensed or linked ring structures, affecting the charge transfer within the molecules of the aromatic phenol compounds with condensed or linked ring structures, promoting intersystem crossing, and at the same time utilizing the rigid network structure of silk to inhibit the non-radiative transition of triplet excitons, thereby extending the phosphorescence lifetime, thereby affecting the duration of the afterglow and improving the long-afterglow phosphorescence performance.

[0014] Preferably, the silk is mulberry silk, which can be in the form of silk or fabric.

[0015] Preferably, the solvent includes methanol, a mixed solution of methanol and water, ethanol, and a mixed solution of ethanol and water.

[0016] Preferably, the solvent is a mixed solution of ethanol and water, and the mass percentage of ethanol in the mixed solution is greater than or equal to 50%.

[0017] Preferably, the solvent is a mixed solution of methanol and water, and the mass percentage of methanol is greater than or equal to 50% based on the mixed solution.

[0018] Preferably, the aromatic phenol compound with a condensed ring or linked ring structure is one or more of p-hydroxybiphenyl, 1-naphthol, 9-phenanthrol, and 1-hydroxypyrene.

[0019] Preferably, the aromatic phenol compound with a condensed ring or linked ring structure is one of 1-naphthol and 9-phenanthrol.

[0020] Preferably, the aromatic phenol compound with a condensed ring or linked ring structure is 1-naphthol.

[0021] Preferably, the aromatic phenol compound with a condensed ring or linked ring structure is 9-phenanthrenol.

[0022] Preferably, the aldehyde is one or more of formaldehyde, vanillin, and cinnamaldehyde.

[0023] Preferably, the aldehyde is formaldehyde.

[0024] Preferably, the molar amount of the formaldehyde is 0.1 to 0.8 times that of the aromatic phenol compound with a condensed ring or linked ring structure.

[0025] In the present application, the aldehyde in the reaction system has a molar quantity that is lower than that of the aromatic phenolic compound with a condensed ring or a ring structure, and still a better long-afterglow phosphor performance can be obtained.

[0026] Preferably, the mass ratio of the silk and the aromatic phenolic compound with a condensed ring or a ring structure is 1:0.1-4.

[0027] Preferably, the mass ratio of the silk and the aromatic phenolic compound with a condensed ring or a ring structure is 1:3-4.

[0028] Preferably, the silk: the aromatic phenolic compound with a condensed ring or a ring structure: solvent = 1g: 0.1g-4g: 50mL-250mL.

[0029] Preferably, the silk: the aromatic phenolic compound with a condensed ring or a ring structure: solvent = 1g: 3g-4g: 50mL-250mL.

[0030] Preferably, the temperature of the reaction is 25-95℃, and the reaction time is 1-24 hours.

[0031] Preferably, the temperature of the reaction is 70-90℃.

[0032] In the present application, the reaction temperature during the reaction has an influence on the long-afterglow room-temperature phosphor silk afterglow duration, and when the temperature of the reaction is 70-90℃, the product obtained has a more comprehensive performance.

[0033] Preferably, the cleaning is washing with an aqueous ethanol solution with a mass percentage of greater than or equal to 50% for at least 3 times.

[0034] The second aspect of the present application provides a long-afterglow room-temperature phosphor silk, which is prepared by the method of the present application.

[0035] The third aspect of the present application provides the application of the long-afterglow room-temperature phosphor silk, which can be used in the fields of anti-counterfeiting and information encryption.

[0036] Under the action of the aldehyde, according to the principle of the Mannich reaction, the active hydrogen sites on the structure of the aromatic phenolic compound with a condensed ring or a ring structure are used for reaction, the aromatic phenolic compound with a condensed ring or a ring structure is grafted to the surface of the silk protein through the amino group of the silk protein, and the silk has excellent long-afterglow room-temperature phosphor performance.

[0037]

[0038] This invention innovatively modifies silk with aromatic phenolic compounds of varying fused or linked ring structures, resulting in products exhibiting differentiated phosphorescence emission characteristics. The phosphorescence color and afterglow duration of the products vary with the molecular structure of the aromatic phenolic compounds. This innovative approach, through the rigid network structure of the silk matrix, inhibits the non-radiative transition of triplet excitons, effectively extending the phosphorescence lifetime and significantly increasing the duration of afterglow, ultimately achieving enhanced long-lasting phosphorescence performance.

[0039] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0040] The present invention achieves modification of silk materials through the Mannich reaction, imparting them with long-lasting room-temperature phosphorescence properties, with an afterglow duration of more than 2 seconds and up to 7.3 seconds. Excellent long-lasting room-temperature phosphorescence properties are exhibited at three excitation wavelengths: 254nm, 302nm, and 365nm. The phosphorescence color and afterglow time can also be regulated according to the type of reactants. When the molar ratio of aldehydes to aromatic phenolic compounds with condensed or linked ring structures is controlled between 0.1 and 0.8, the resulting product can still maintain a long-lasting room-temperature phosphorescence property of more than 2 seconds. The long-lasting room-temperature phosphorescent silk obtained by the method of the present invention has phosphorescent groups that are firmly chemically bonded to the surface of the material and are not easily detached, further ensuring the stability of the product. The preparation method of the present invention is simple to operate, low-cost, and has good prospects for industrial application. More importantly, the long-lasting room-temperature phosphorescent silk obtained by the present invention exhibits broad application potential in fields such as anti-counterfeiting identification and information encryption. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is an optical test image of the product prepared in Example 1.

[0042] a is the phosphorescence spectrum of the excitation wavelength 254nm; b is the phosphorescence spectrum of the excitation wavelength 302nm; c is the phosphorescence spectrum of the excitation wavelength 365nm;

[0043] Figure 2 This is an optical test image of the product prepared in Example 11.

[0044] a is the phosphorescence spectrum of the excitation wavelength 254nm; b is the phosphorescence spectrum of the excitation wavelength 302nm; c is the phosphorescence spectrum of the excitation wavelength 365nm;

[0045] Figure 3 This is an optical test image of the product prepared in Example 13.

[0046] a is the phosphorescence spectrum of the excitation wavelength 254nm; b is the phosphorescence spectrum of the excitation wavelength 302nm; c is the phosphorescence spectrum of the excitation wavelength 365nm;

[0047] Figure 4 Optical test chart of the product prepared for Example 14,

[0048] a is the phosphorescence spectrum chart of excitation wavelength 254 nm; b is the phosphorescence spectrum chart of excitation wavelength 302 nm; c is the phosphorescence spectrum chart of excitation wavelength 365 nm;

[0049] Figure 5 254 nm, 302 nm and 365 nm afterglow duration test chart of the product prepared for Example 1;

[0050] Figure 6 254 nm, 302 nm and 365 nm afterglow duration test chart of the product prepared for Example 11;

[0051] Figure 7 254 nm, 302 nm and 365 nm afterglow duration test chart of the product prepared for Example 13;

[0052] Figure 8 254 nm, 302 nm and 365 nm afterglow duration test chart of the product prepared for Example 14. DETAILED DESCRIPTION

[0053] The present application will be further described below in conjunction with the accompanying drawings and specific examples, but the examples do not limit the present application in any form. Unless otherwise specified, the reagents, methods and equipment used in the present application are conventional reagents, methods and equipment in the technical field.

[0054] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0055] The present application provides a preparation method of phosphorescent silk, which reacts the silk in a solvent containing aromatic phenolic compounds with condensed ring or annular structure and aldehyde. According to the principle of Mannich reaction, the reactive hydrogen sites on the phenol structure are used for reaction, and the aromatic phenolic compounds with condensed ring or annular structure are grafted to the surface of the silk, so that the silk has excellent phosphorescent performance. Moreover, the method is simple in operation, low in cost and stable in performance.

[0056] Example 1

[0057] A long afterglow room temperature phosphorescent silk, the preparation method thereof comprises the following steps:

[0058] (1) Cut and weigh 1 g of mulberry silk;

[0059] (2) Weigh 4 g of 1-naphthol, dissolve it in 50 mL of 80% ethanol aqueous solution, then add 3 g of formaldehyde, and the molar amount of formaldehyde is about 3.6 times of the molar amount of 1-naphthol, to form a uniform reaction system;

[0060] (3) completely immersing the silk in the above solution and reacting at 80°C for 12 hours;

[0061] (4) After the reaction is completed, the silk is taken out, washed five times with 80% ethanol aqueous solution, and dried to obtain silk with long afterglow room temperature phosphorescence.

[0062] Example 2

[0063] A long-lasting room-temperature phosphorescent silk, the preparation method of which comprises the following steps:

[0064] (1) Cut the mulberry silk and weigh 1g;

[0065] (2) Weighing 4 g of 1-naphthol, dissolving it in 50 mL of 80% ethanol aqueous solution, and then adding 0.1 g of formaldehyde (the molar amount of formaldehyde is approximately 0.12 times the molar amount of 1-naphthol) to form a uniform reaction system;

[0066] (3) completely immersing the silk in the above solution and reacting at 80°C for 12 hours;

[0067] (4) After the reaction is completed, the silk is taken out, washed five times with 80% ethanol aqueous solution, and dried to obtain silk with long afterglow room temperature phosphorescence.

[0068] Example 3

[0069] A long-lasting room-temperature phosphorescent silk, the preparation method of which comprises the following steps:

[0070] (1) Cut the mulberry silk and weigh 1g;

[0071] (2) Weighing 4 g of 1-naphthol, dissolving it in 250 mL of 100% ethanol, and then adding 3 g of formaldehyde (the molar amount of formaldehyde is approximately 3.6 times the molar amount of 1-naphthol) to form a uniform reaction system;

[0072] (3) completely immersing the silk in the above solution and reacting at 25°C for 12 hours;

[0073] (4) After the reaction is completed, the silk is taken out, washed five times with 80% ethanol aqueous solution, and dried to obtain silk with long afterglow room temperature phosphorescence.

[0074] Example 4

[0075] A long-lasting room-temperature phosphorescent silk, the preparation method of which comprises the following steps:

[0076] (1) Cut the mulberry silk and weigh 1g;

[0077] (2) Weigh 3 g of 1-naphthol and dissolve it in 50 mL of 80% ethanol. Then add 0.5 g of formaldehyde (the molar amount of formaldehyde is approximately 0.8 times the molar amount of 1-naphthol) to form a uniform reaction system.

[0078] (3) completely immersing the silk in the above solution and reacting at 70°C for 12 hours;

[0079] (4) After the reaction is completed, the silk is taken out, washed five times with 80% ethanol aqueous solution, and dried to obtain silk with long afterglow room temperature phosphorescence.

[0080] Example 5

[0081] A long-lasting room-temperature phosphorescent silk, the preparation method of which comprises the following steps:

[0082] (1) Cut the mulberry silk and weigh 1g;

[0083] (2) Weigh 4 g of 1-naphthol and dissolve it in 50 mL of 80% ethanol. Then, add 3 g of formaldehyde (the molar amount of formaldehyde is approximately 3.6 times the molar amount of 1-naphthol) to form a uniform reaction system.

[0084] (3) Immerse the silk completely in the above solution and react at 95°C for 1 hour;

[0085] (4) After the reaction is completed, the silk is taken out, washed five times with 80% ethanol aqueous solution, and dried to obtain silk with long afterglow room temperature phosphorescence.

[0086] Example 6

[0087] A long-lasting room-temperature phosphorescent silk, the preparation method of which comprises the following steps:

[0088] (1) Cut the mulberry silk and weigh 1g;

[0089] (2) Weighing 4 g of 1-naphthol, dissolving it in 100 mL of a 50% methanol aqueous solution, and then adding 3 g of formaldehyde (the molar amount of formaldehyde is approximately 3.6 times the molar amount of 1-naphthol) to form a uniform reaction system;

[0090] (3) completely immersing the silk in the above solution and reacting at 90°C for 24 hours;

[0091] (4) After the reaction is completed, the silk is taken out, washed five times with 80% ethanol aqueous solution, and dried to obtain silk with long afterglow room temperature phosphorescence.

[0092] Example 7

[0093] A long-lasting room-temperature phosphorescent silk, the preparation method of which comprises the following steps:

[0094] (1) Cut the mulberry silk and weigh 1g;

[0095] (2) Weighing 4 g of 1-naphthol, dissolving it in 100 mL of 100% methanol, and then adding 3 g of formaldehyde (the molar amount of formaldehyde is approximately 3.6 times the molar amount of 1-naphthol) to form a uniform reaction system;

[0096] (3) completely immersing the silk in the above solution and reacting at 80°C for 6 hours;

[0097] (4) After the reaction is completed, the silk is taken out, washed five times with 80% ethanol aqueous solution, and dried to obtain silk with long afterglow room temperature phosphorescence.

[0098] Example 8

[0099] A long-lasting room-temperature phosphorescent silk, the preparation method of which comprises the following steps:

[0100] (1) Cut the mulberry silk and weigh 1g;

[0101] (2) Weigh 4 g of 1-naphthol and dissolve it in 100 mL of 50% ethanol. Then, add 5 g of vanillin (the molar amount of vanillin is approximately 1.2 times the molar amount of 1-naphthol) to form a uniform reaction system.

[0102] (3) completely immersing the silk in the above solution and reacting at 80°C for 10 hours;

[0103] (4) After the reaction is completed, the silk is taken out, washed five times with 80% ethanol aqueous solution, and dried to obtain silk with long afterglow room temperature phosphorescence.

[0104] Example 9

[0105] A long-lasting room-temperature phosphorescent silk, the preparation method of which comprises the following steps:

[0106] (1) Cut the mulberry silk and weigh 1g;

[0107] (2) Weighing 4 g of 1-naphthol, dissolving it in 100 mL of 50% ethanol, and then adding 6 g of cinnamaldehyde (the molar amount of cinnamaldehyde is approximately 1.6 times the molar amount of 1-naphthol) to form a uniform reaction system;

[0108] (3) completely immersing the silk in the above solution and reacting at 80°C for 8 hours;

[0109] (4) After the reaction is completed, the silk is taken out, washed five times with 80% ethanol aqueous solution, and dried to obtain silk with long afterglow room temperature phosphorescence.

[0110] Example 10

[0111] A long afterglow room temperature phosphorescent silk, the preparation method comprising the following steps:

[0112] (1) cut and weigh 1g of mulberry silk;

[0113] (2) weigh 0.1g of p-hydroxybiphenyl, dissolve it in 150mL of 80% ethanol aqueous solution, then add 0.05g of formaldehyde, the molar amount of formaldehyde is about 2.8 times of the molar amount of p-hydroxybiphenyl, to form a uniform reaction system;

[0114] (3) completely immerse the silk in the above solution, and react at 80℃ for 12 hours;

[0115] (4) after the reaction is completed, take out the silk, wash it with 80% ethanol aqueous solution for 5 times, and dry to obtain long afterglow room temperature phosphorescent silk.

[0116] Example 11

[0117] A long afterglow room temperature phosphorescent silk, the preparation method comprising the following steps:

[0118] (1) cut and weigh 1g of mulberry silk;

[0119] (2) weigh 2g of p-hydroxybiphenyl, dissolve it in 100mL of 80% ethanol aqueous solution, then add 0.5g of formaldehyde, the molar amount of formaldehyde is about 1.4 times of the molar amount of p-hydroxybiphenyl, to form a uniform reaction system;

[0120] (3) completely immerse the silk in the above solution, and react at 80℃ for 12 hours;

[0121] (4) after the reaction is completed, take out the silk, wash it with 80% ethanol aqueous solution for 5 times, and dry to obtain long afterglow room temperature phosphorescent silk.

[0122] Example 12

[0123] A long afterglow room temperature phosphorescent silk, the preparation method comprising the following steps:

[0124] (1) cut and weigh 1g of mulberry silk;

[0125] (2) weigh 3g of 9-phenanthrol, dissolve it in 250mL of 80% ethanol aqueous solution, then add 0.1g of formaldehyde, the molar amount of formaldehyde is about 0.22 times of the molar amount of 9-phenanthrol, to form a uniform reaction system;

[0126] (3) completely immerse the silk in the above solution, and react at 80℃ for 12 hours;

[0127] (4) After the reaction is completed, the silk is taken out, washed five times with 80% ethanol aqueous solution, and dried to obtain silk with long afterglow room temperature phosphorescence.

[0128] Example 13

[0129] A long-lasting room-temperature phosphorescent silk, the preparation method of which comprises the following steps:

[0130] (1) Cut the mulberry silk and weigh 1g;

[0131] (2) Weighing 2.5 g of 9-phenanthrenol and dissolving it in 250 mL of 80% ethanol aqueous solution, followed by adding 0.3 g of formaldehyde (the molar amount of formaldehyde is approximately 0.78 times the molar amount of 9-phenanthrenol) to form a uniform reaction system;

[0132] (3) completely immersing the silk in the above solution and reacting at 80°C for 12 hours;

[0133] (4) After the reaction is completed, the silk is taken out, washed five times with 80% ethanol aqueous solution, and dried to obtain silk with long afterglow room temperature phosphorescence.

[0134] Example 14

[0135] A long-lasting room-temperature phosphorescent silk, the preparation method of which comprises the following steps:

[0136] (1) Cut the mulberry silk and weigh 1g;

[0137] (2) Weigh 1 g of 1-hydroxypyrene and dissolve it in 250 mL of 80% ethanol aqueous solution. Then add 0.3 g of formaldehyde (the molar amount of formaldehyde is approximately 2.2 times the molar amount of 1-hydroxypyrene) to form a uniform reaction system.

[0138] (3) completely immersing the silk in the above solution and reacting at 80°C for 12 hours;

[0139] (4) After the reaction is completed, the silk is taken out, washed five times with 80% ethanol aqueous solution, and dried to obtain silk with long afterglow room temperature phosphorescence.

[0140] Example 15

[0141] A long-lasting room-temperature phosphorescent silk, the preparation method of which comprises the following steps:

[0142] (1) Cut the mulberry silk and weigh 1g;

[0143] (2) Weigh 4 g of 1-hydroxypyrene and dissolve it in 250 mL of 80% ethanol aqueous solution. Then, add 2 g of formaldehyde (the molar amount of formaldehyde is approximately 3.6 times the molar amount of 1-hydroxypyrene) to form a uniform reaction system.

[0144] (3) completely immersing the silk in the above solution and reacting at 80°C for 12 hours;

[0145] (4) After the reaction is completed, the silk is taken out, washed five times with 80% ethanol aqueous solution, and dried to obtain silk with long afterglow room temperature phosphorescence.

[0146] Comparative Example 1

[0147] A phosphorescent silk, the preparation method of which comprises the following steps:

[0148] (1) Cut the mulberry silk and weigh 1g;

[0149] (2) Weighing 4 g of 1-naphthol, dissolving it in 50 mL of 80% ethanol aqueous solution, and then adding 4 g of formaldehyde (the molar amount of formaldehyde is approximately 4.8 times that of 1-naphthol) to form a uniform reaction system;

[0150] (3) completely immersing the silk in the above solution and reacting at 80°C for 12 hours;

[0151] (4) After the reaction is completed, the silk is taken out, washed five times with 80% ethanol aqueous solution, and dried to obtain phosphorescent silk.

[0152] Comparative Example 2

[0153] A phosphorescent silk, the preparation method of which comprises the following steps:

[0154] (1) Cut the mulberry silk and weigh 1g;

[0155] (2) Weighing 4 g of 1-naphthol, dissolving it in 50 mL of 80% ethanol aqueous solution, and then adding 0.01 g of formaldehyde (the molar amount of formaldehyde is approximately 0.01 times the molar amount of 1-naphthol) to form a uniform reaction system;

[0156] (3) completely immersing the silk in the above solution and reacting at 80°C for 12 hours;

[0157] (4) After the reaction is completed, the silk is taken out, washed five times with 80% ethanol aqueous solution, and dried to obtain phosphorescent silk.

[0158] Comparative Example 3

[0159] A phosphorescent silk, the preparation method of which comprises the following steps:

[0160] (1) Cut the mulberry silk and weigh 1g;

[0161] (2) Weighing 4 g of curcumin, dissolving it in 50 mL of 80% ethanol aqueous solution, and then adding 1.2 g of formaldehyde (the molar amount of formaldehyde is approximately 3.7 times the molar amount of 1-hydroxypyrene) to form a uniform reaction system;

[0162] (3) completely immersing the silk in the above solution and reacting at 80°C for 12 hours;

[0163] (4) After the reaction is completed, the silk is taken out, washed five times with 80% ethanol aqueous solution, and dried to obtain phosphorescent silk.

[0164] Comparative Example 4

[0165] The comparative example of the present invention provides a phosphorescent silk, and the preparation method thereof comprises the following steps: the difference from Example 1 is that formaldehyde is not added in step (3).

[0166] Comparative Example 5

[0167] A long-lasting room-temperature phosphorescent silk, the preparation method of which comprises the following steps:

[0168] (1) Cut the mulberry silk and weigh 1g;

[0169] (2) Weighing 4 g of 1-naphthol, dissolving it in 30 mL of 80% ethanol aqueous solution, and then adding 3 g of formaldehyde (the molar amount of formaldehyde is approximately 3.6 times the molar amount of 1-naphthol) to form a uniform reaction system;

[0170] (3) completely immersing the silk in the above solution and reacting at 80°C for 12 hours;

[0171] (4) After the reaction is completed, the silk is taken out, washed five times with 80% ethanol aqueous solution, and dried to obtain silk with long afterglow room temperature phosphorescence.

[0172] Comparative Example 6

[0173] A long-lasting room-temperature phosphorescent silk, the preparation method of which comprises the following steps:

[0174] (1) Cut the mulberry silk and weigh 1g;

[0175] (2) Weighing 4 g of 1-naphthol, dissolving it in 300 mL of 80% ethanol solution, and then adding 3 g of formaldehyde (the molar amount of formaldehyde is approximately 3.6 times the molar amount of 1-naphthol) to form a uniform reaction system;

[0176] (3) completely immersing the silk in the above solution and reacting at 80°C for 12 hours;

[0177] (4) After the reaction is completed, the silk is taken out, washed five times with 80% ethanol aqueous solution, and dried to obtain silk with long afterglow room temperature phosphorescence.

[0178] Comparative Example 7

[0179] A long-lasting room-temperature phosphorescent silk, the preparation method of which comprises the following steps:

[0180] (1) Cut the cotton fabric and weigh 1g;

[0181] (2) Weighing 4 g of 1-naphthol, dissolving it in 100 mL of 80% ethanol, and then adding 3 g of formaldehyde (the molar amount of formaldehyde is approximately 3.6 times the molar amount of 1-naphthol) to form a uniform reaction system;

[0182] (3) Immerse the cotton fabric completely in the above solution and react at 80°C for 6 hours;

[0183] (4) After the reaction is completed, the cotton fabric is taken out, washed five times with 80% ethanol aqueous solution, and dried.

[0184] Effect Examples

[0185] Delayed photoluminescence spectra (delay time: 1 ms) were measured on a Hitachi F-7000 fluorescence spectrophotometer. Afterglow luminescence images were taken with an iPhone 15 Pro Max using a darkroom UV analyzer at room temperature.

[0186] The results are shown in Table 1;

[0187] Table 1 Afterglow duration and afterglow color of long afterglow room temperature phosphorescent silk

[0188]

[0189]

[0190] As can be seen from Table 1, when the technical solution of the present invention is adopted, the obtained product has excellent long-afterglow room-temperature phosphorescence characteristics, with an afterglow time of more than 2 seconds. The long-afterglow room-temperature phosphorescence characteristics with an afterglow time of more than 2 seconds can be achieved at the three excitation wavelengths of 254nm, 302nm and 365nm. The phosphorescence color and afterglow time can also be adjusted according to the type of reactants.

[0191] It can be seen from Example 1, Example 2, Example 4, Example 12, and Example 13 that when the molar ratio of formaldehyde to the aromatic phenol compounds with condensed ring or linked ring structure in the reaction system is between 0.1 and 0.8, there is no significant decrease compared with Example 1 (molar ratio 3.6), and the afterglow time of the long afterglow room temperature phosphorescence of the obtained product can reach more than 2 seconds.

[0192] From the example 1 and the comparative examples 1-2, it can be seen that the molar ratio of formaldehyde to the aromatic phenolic compound with fused ring or annular structure in the reaction system has an influence on the performance of the product. From the comparative examples 1-2, it can be seen that when the molar ratio of formaldehyde to the aromatic phenolic compound with fused ring or annular structure is not within the range given in the present application, specifically, when the molar ratio of formaldehyde to the aromatic phenolic compound with fused ring or annular structure is too large in the comparative example 1, the afterglow time of the obtained product is significantly weakened, and the afterglow time is not more than 0.5 seconds; when the molar ratio of formaldehyde to the aromatic phenolic compound with fused ring or annular structure is too small in the comparative example 2, the long afterglow room temperature phosphorescence performance of the obtained product is greatly weakened, and the afterglow time is only 0.1 seconds under the excitation wavelength of 254 nm, and the product does not have the long afterglow room temperature phosphorescence performance under the excitation of 302 nm and 365 nm.

[0193] From the example 4, the example 8 and the example 9, it can be seen that the adjustment of the type of aldehyde in the reaction system does not have a significant change on the product, and the afterglow time of the long afterglow room temperature phosphorescence of the obtained product can reach more than 2 seconds. The product obtained by using vanillin and cinnamyl aldehyde has an afterglow time of 3.3 seconds under the excitation of 254 nm.

[0194] From the example 1, the comparative example 5 and the comparative example 6, it can be seen that the volume of the solvent in the reaction system will affect the comprehensive performance of the product, and when the volume of the solvent in the system is not within the preferred range given in the present application, the long afterglow room temperature phosphorescence performance of the obtained product is weakened, and the afterglow time is less than 2 seconds under the excitation of 254 nm.

[0195] From the example 1 and the comparative example 3, it can be seen that when other polycyclic compounds are used, the obtained product does not have the long afterglow room temperature phosphorescence performance; from the example 1 and the comparative examples 3-4, it can be seen that whether the aromatic phenolic compound lacks the fused ring or annular structure or the formaldehyde is absent, the product does not have the long afterglow room temperature phosphorescence performance, and the product of the present application cannot be prepared. From the example 1 and the comparative example 7, it can be seen that when cotton fabric is used as the reaction raw material, the obtained product does not have the long afterglow room temperature phosphorescence performance.

[0196] Obviously, the above examples of the present application are only examples for clearly illustrating the present application, and are not intended to limit the embodiments of the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, it is not necessary and impossible to exhaust all the embodiments. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A method for preparing long-lasting room-temperature phosphorescent silk, characterized in that: The preparation method comprises the following steps: The silk is immersed in the reaction system for reaction, and after the reaction, the silk is taken out, washed, and dried to obtain the long-lasting room-temperature phosphorescent silk; The reaction system comprises a solvent, an aromatic phenol compound with a condensed ring or linked ring structure, and an aldehyde; The molar amount of the aldehyde is 0.1 to 4 times the molar amount of the aromatic phenol compound with a condensed ring or linked ring structure.

2. The preparation method according to claim 1, characterized in that The aromatic phenol compound with a condensed ring or linked ring structure is one or more of p-hydroxybiphenyl, 1-naphthol, 9-phenanthrol, and 1-hydroxypyrene.

3. The preparation method according to claim 1, characterized in that The aldehyde is one or more of formaldehyde, cinnamaldehyde or vanillin.

4. The preparation method according to claim 3, characterized in that The solvent includes methanol, a mixed solution of methanol and water, ethanol, and a mixed solution of ethanol and water; the mass percentage of methanol in the mixed solution of methanol and water is greater than or equal to 50%; the mass percentage of ethanol in the mixed solution of ethanol and water is greater than or equal to 50%.

5. The preparation method according to claim 1, characterized in that The mass ratio of the silk to the aromatic phenol compound containing a condensed ring or linked ring structure is 1:0.1-4.

6. The preparation method according to claim 1, characterized in that The silk: aromatic phenol compound with condensed ring or linked ring structure: solvent = 1g: 0.1g-4g: 50mL-250mL.

7. The preparation method according to claim 1, characterized in that The molar amount of the aldehyde is 0.1 to 0.8 times the molar amount of the aromatic phenol compound with a condensed ring or linked ring structure.

8. The preparation method according to claim 1, characterized in that The reaction temperature is 25 to 95° C., and the reaction time is 1 to 24 hours.

9. The long-afterglow room-temperature phosphorescent silk prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the long-lasting room-temperature phosphorescent silk according to claim 9 in anti-counterfeiting and information encryption materials.

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