Fluorescent probe for post-modification of polymer, preparation method and application of fluorescent probe, polymer modified with fluorescent probe and application of polymer

Abstract

The invention belongs to the field of polymer post-modification, and particularly relates to a fluorescent probe for polymer post-modification, a preparation method and application thereof, a polymer modified with the fluorescent probe and application thereof, the fluorescent probe has a structural general formula as shown in formula I, II or III: # imgabs0 #, R1 and R3 are independently selected from a hydrogen atom, a nitro group, a phenyl group, an alkyl group, a cyano group, a methoxyl group or a halogen atom, and R2 and R3 are independently selected from a hydrogen atom, a nitro group, a phenyl group, an alkyl group, a cyano group, a methoxyl group or a halogen atom; and R2, R4 and R5 are independently selected from a conjugate formed by one or more groups in formulas (I)-(XV): # imgabs1. Compared with the prior art, the invention solves the problems that the mechanical property of the polymer is reduced and the application range of the polymer is limited by post-modification of the polymer in the prior art. According to the scheme, a novel polymer post-modification method is provided, a series of universal fluorescent molecules are synthesized, and then polymer screening and anti-counterfeiting can be achieved.

Description

Technical Field

[0001] The invention belongs to the field of polymer post-modification, and specifically relates to a fluorescent probe for polymer post-modification and a preparation method and application thereof, a polymer modified with the fluorescent probe and an application thereof. Background Art

[0002] Polymer post-modification usually modifies existing polymers to improve the performance of the polymers or expand the application of the polymers. Especially for polyolefin materials, such as polyethylene, polypropylene, etc., despite their excellent performance, the lack of polar groups limits their scope of application. One of the important reasons for the widespread application of commercial polymers is their stability, which also determines that commercial polymer post-modification generally requires extremely high temperatures and harsh conditions. The existing methods of polymer post-modification mainly include free radical methods, metal catalysis methods, etc.: free radical methods usually have some side reactions, resulting in the breakage of the polymer molecular chain, the reduction of molecular weight, and the reduction of the mechanical properties of the polymer; metal catalysis methods will introduce metal elements into the polymer, limiting the scope of use of the polymer.

[0003] Therefore, in order to solve the problem of post-modification of polymers, a new method needs to be developed to achieve polymer modification.

[0004] In addition, plastic pollution is increasingly becoming a global problem. The current methods of plastic disposal mainly include incineration, landfill and recycling. The incineration and landfill of plastics will cause a lot of environmental pollution and waste of resources. The recycling of plastics is the effective way to deal with waste plastics. The recycling of plastics generally involves a series of steps such as sorting, cleaning, and drying. Plastic sorting includes manual sorting, sorting based on sinking and floating methods, and sorting based on infrared. However, these sorting methods are rough sorting of plastics, and can only sort out different types of plastics. It is impossible to further sort the same type and different models of plastics. Adding organic fluorescent molecules to polymers can be used for tracking and sorting of polymers throughout their life cycle. The realization of polymer fluorescence through chemical modification can achieve the classification and tracking of polymers.

[0005] This shows that it is currently necessary to modify fluorescent molecules into polymers under mild conditions to achieve fluorescent labeling and classification tracking of polymers. Summary of the invention

[0006] The purpose of the present invention is to solve at least one of the above problems and provide a fluorescent probe for polymer post-modification and its preparation method and application, a polymer modified with a fluorescent probe and its application, so as to solve the problem that polymer post-modification in the prior art will reduce the mechanical properties of the polymer and limit the scope of use of the polymer. This scheme provides a new polymer post-modification method, synthesizes a series of universal fluorescent molecules, and further realizes polymer screening and anti-counterfeiting.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] The first aspect of the present invention discloses a fluorescent probe for polymer post-modification, having a general structural formula of Formula I, II or III:

[0009]

[0010] Among them, R 1 and R 3 independently selected from hydrogen, nitro, phenyl, alkyl, cyano, methoxy or halogen atoms;

[0011] R 2 , R 4 and R 5 A conjugate formed by one or more groups independently selected from formula (I) to (XV):

[0012]

[0013] The second aspect of the present invention discloses a method for preparing the fluorescent probe for polymer post-modification as described above, comprising the following steps:

[0014] S1: a compound containing an acyl chloride group and an alcohol containing a fluorescent group undergo an esterification reaction under the catalysis of a base to obtain a corresponding ester;

[0015] S2: reacting the ester obtained in step S1 with an azide compound under the action of DBU or triethylamine to obtain a corresponding fluorescent probe.

[0016] Preferably, the compound containing an acyl chloride group is phenylacetyl chloride or methyl malonyl chloride; and the azide compound is p-toluenesulfonyl azide or 4-acetamidobenzenesulfonyl azide.

[0017] Preferably, in step S1, the compound containing an acyl chloride group and the base are added in excess according to a stoichiometric ratio, specifically, the alcohol containing a fluorescent group: the compound containing an acyl chloride group: the base (such as triethylamine) = 1 mol: (1.05-2.0) mol: (1.5-4.0) mol are used, the reaction is initially carried out at 0°C, the reaction is restored to room temperature after 0.5h, the reaction is terminated after 12h, and the pure product is obtained by separation through a silica gel column; in step S2, the azide compound and the base are added in excess according to a stoichiometric ratio, specifically, the ester synthesized in the first step: p-toluenesulfonyl azide or 4-acetylaminobenzenesulfonyl azide: the base (DBU or triethylamine) = 1 mol: (1.5-3.0) mol: (1.5-4.0) mol are used, the reaction is initially carried out at 0°C, the reaction is restored to room temperature after 0.5h, the reaction is terminated after 24h, and the pure product is obtained by separation through a silica gel column.

[0018] The third aspect of the present invention discloses an application of the fluorescent probe for post-modification of polymers as described above, wherein the fluorescent probe modifies polymers containing aliphatic carbon-hydrogen bonds, or modifies polymers containing active hydrogen; the active hydrogen includes hydroxyl, carboxyl and amino.

[0019] The fourth aspect of the present invention discloses a polymer modified with a fluorescent probe, which is obtained by post-modifying a polymer containing aliphatic carbon-hydrogen bonds with the fluorescent probe as described above; the post-modification modification methods include solution method, bulk method and extrusion method.

[0020] Preferably, the polymer includes polyolefin plastics, polyester plastics, polylactone plastics, polyacrylate plastics, polymethacrylate plastics, polyurethane plastics and copolymer plastics.

[0021] Preferably, the added amount of the fluorescent probe is 0.001-10% of the total mass of the polymer.

[0022] The fifth aspect of the present invention discloses the use of a polymer modified with a fluorescent probe as described above in polymer sorting.

[0023] The sixth aspect of the present invention discloses an application of a polymer modified with a fluorescent probe as described above in polymer anti-counterfeiting.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The fluorescent probe obtained by the present invention can realize post-modification of different commercial polymers, and the post-modified polymer can realize adjustable fluorescence intensity and adjustable emission wavelength.

[0026] The polymer modified by the fluorescent probe can be used for polymer classification and screening, polymer anti-counterfeiting and other aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is the NMR spectrum of the polymer before and after modification in Example 7;

[0028] Figure 2 : is the fluorescence spectra of the polymers at different modification amounts in Example 7;

[0029] Figure 3 is the change in fluorescence intensity of the polymer under different modification amounts in Example 7;

[0030] Figure 4 is the glass transition temperature of the polymer at different modification amounts in Example 7;

[0031] Figure 5 The actual image and fluorescence spectrum of the polymer before and after modification in Example 9;

[0032] Figure 6 These are the tensile test results of the polymer before and after modification in Example 9. DETAILED DESCRIPTION

[0033] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] In the following description:

[0035] 1) Analytical instruments:

[0036] 400MHz Fourier transform nuclear magnetic resonance spectrometer AVANCE III HD, manufacturer: Bruker.

[0037] Differential scanning calorimeter Q2000, manufacturer: TA.

[0038] Internal mixer (Torque Rheological Processing System Rheomix 600), manufacturer: ThermoFisher.

[0039] Twin-screw extruder (Micro Processing Systems - Desktop Twin-screw Extruder, process 11), manufacturer: ThermoFisher.

[0040] Flat vulcanizing machine, manufacturer: China Taiwan High Speed ​​Rail Testing Equipment.

[0041] High-resolution steady-state fluorescence spectrometer (FLS1000), manufacturer: Edinburgh Instruments.

[0042] Universal electronic testing machine Instron 5966, manufacturer: Instron.

[0043] 2) Reagents:

[0044] Phenylacetyl chloride, 99%, Adamas.

[0045] 9-Anthracenemethanol, 99%, Adamas.

[0046] 1-Naphthol, 99%, Adamas.

[0047] N,N-dimethylformamide, analytical grade, Chinese medicine.

[0048] 2-Bromoethanol, 96%, Merrill.

[0049] Potassium carbonate, 99%, Sinopharm.

[0050] Benzophenone, 99%, Adamas.

[0051] 4-Hydroxybenzophenone, 98%, Adamas.

[0052] Zinc powder, 95%, Sinopharm.

[0053] Titanium tetrachloride (TiCl 4 ), 99%, Adamas.

[0054] 4,7-Dibromo-2,1,3-benzothiadiazole, 98%, Adamas.

[0055] 4-Hydroxymethylphenylboronic acid, 97%, Adamas.

[0056] Tetrakis(triphenylphosphine)palladium, 98%, Adamas.

[0057] Toluene, analytical grade, Greagent.

[0058] Methyl malonyl chloride, 97%, Adamas.

[0059] 4-Acetamidobenzenesulfonyl azide, 98%, Adamas.

[0060] Acetonitrile, extra dry, Adamas.

[0061] Tributyl(2-thienyl)tin, 97%, Adamas.

[0062] 4-Triphenylamine borate, 98%, Adamas.

[0063] Triethylamine, 99%, Sinopharm

[0064] Dichloromethane, 99.9%, Adamas.

[0065] p-Toluenesulfonyl azide (TsN 3 ), 98%, Adamas

[0066] 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU), 98%, Adamas.

[0067] Petroleum ether, Greagent

[0068] Ethyl acetate, ≥99.5%, Greagent

[0069] Polystyrene, Ningbo Liwan New Materials Co., Ltd.

[0070] High-density polyethylene (HDPE), Sinopec

[0071] Polypropylene (PP), Daelim Co., Ltd., South Korea.

[0072] ABS, Shanghai Polytec Composite Materials Co., Ltd.

[0073] ABS / PC, Shanghai Polytec Composite Materials Co., Ltd.

[0074] The remaining reagents not specifically described are conventional commercially available products, and the methods not specifically described are well known in the art.

[0075] In view of the problem of achieving polymer fluorescence by post-modification methods and the shortcomings of traditional modification methods, the present invention provides a new polymer post-modification method and synthesizes a series of universal fluorescent probes (also known as fluorescent molecules) that can be used to achieve polymer screening and anti-counterfeiting.

[0076] The universal fluorescent molecule provided by the present invention is a fluorescent molecule based on the carbene carbon-hydrogen insertion mechanism. The fluorescent molecule obtained by this method can realize post-modification of commercial polymers under mild conditions to achieve polymer post-modification effects. The modified polymer can realize fluorescence sorting and anti-counterfeiting.

[0077] Specifically,

[0078] The present invention provides a general method for synthesizing fluorescent molecules, comprising the following steps:

[0079] 1) Using phenylacetyl chloride or methyl malonyl chloride and alcohol or phenol containing a fluorescent group to undergo an esterification reaction under the catalysis of a base to generate the corresponding ester.

[0080] 2) Using the ester synthesized in step 1) and p-toluenesulfonyl azide (TsN 3 ) or 4-acetylaminobenzenesulfonyl azide (ABSA) reacts with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) or triethylamine to obtain a fluorescent molecule.

[0081] In one embodiment, the method for synthesizing the universal fluorescent molecule comprises the following steps:

[0082] 1) Dissolve the alcohol containing a diazo group and excess phenylacetyl chloride in dichloromethane, add excess triethylamine dropwise to the reaction solution at 0°C, then gradually return to room temperature and stir overnight. Then pass through a silica gel column to obtain the corresponding ester.

[0083] 2) The ester obtained in step 1) and p-toluenesulfonyl azide (TsN 3 ) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) were dissolved in dichloromethane, stirred at room temperature for 24 h, and separated by a silica gel column to obtain the corresponding fluorescent molecules.

[0084] In another embodiment, the method for synthesizing the universal fluorescent molecule comprises the following steps:

[0085] 1) Dissolve the alcohol containing a diazo group and methyl malonate chloride in dichloromethane, add excess triethylamine dropwise to the reaction solution at 0°C, then gradually return to room temperature and stir overnight. Then separate and purify by silica gel column to obtain the corresponding ester.

[0086] 2) The ester synthesized in step 1) is reacted with 4-acetylaminobenzenesulfonyl azide (ABSA) under the action of triethylamine to obtain a compound which is the obtained fluorescent molecule. Specifically, the ester synthesized in step 1) and 4-acetylaminobenzenesulfonyl azide (ABSA) and triethylamine are dissolved in dichloromethane, stirred at room temperature for 24 hours, and separated and purified by a silica gel column to obtain the corresponding fluorescent molecule.

[0087] In the above 1), the alcohol containing a diazo group: phenylacetyl chloride or methyl malonyl chloride: triethylamine = 1 mol: (1.05-2.0) mol: (1.5-4.0) mol are used, and the reaction is initially carried out at 0°C, and the temperature is returned to room temperature after 0.5 h of reaction. The reaction is terminated after 12 h of reaction, and the pure product is obtained by separation through a silica gel column.

[0088] In the above 2), the ester synthesized according to 1): p-toluenesulfonyl azide or 4-acetamidobenzenesulfonyl azide: DBU or triethylamine = 1 mol: (1.5-3.0) mol: (1.5-4.0) mol is used, the reaction is initially carried out at 0°C, the temperature is returned to room temperature after 0.5h of reaction, the reaction is terminated after 24h of reaction, and the pure product is obtained by separation by silica gel column.

[0089] The present invention provides a universal fluorescent molecule obtained by the above method, and the obtained fluorescent molecule has a general structural formula shown in the following formula I, II or III:

[0090]

[0091] Where R 1 , R 3 are independently selected from hydrogen, nitro, phenyl, alkyl, cyano, methoxy or halogen atoms, R 2 , R 4 It is a conjugate of one or more groups including but not limited to the following formulas (I) to (XV):

[0092]

[0093] For example, R 2 , R 4 , R 5 It can be a conjugate of the following groups, but is not limited to the following groups. It can also be a conjugate of any of the above fluorescent groups:

[0094]

[0095] The present invention also provides that the fluorescent molecule is used to post-modify a polymer, so as to achieve modification of a polymer containing aliphatic carbon-hydrogen bonds and a polymer containing active hydrogen, wherein the active hydrogen includes a hydroxyl group, a carboxyl group, and an amino group.

[0096] In one embodiment of the present invention, the polymer used for modification includes: 1) polyolefin plastics, including common polyolefin plastics such as polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS); 2) polyester plastics, including common polyester plastics such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polybutylene terephthalate-adipate (PBAT); 3) polylactone plastics, including common polyester plastics such as polycaprolactone (PCL), polylactic acid (PLA), polycarbonate (PC); 4) polyacrylate plastics, including polymethyl acrylate (PMA), poly ethyl acrylate (PEA), polybutyl acrylate (PnBA) and other common polyacrylate series plastics; 5) polymethacrylate plastics, including polymethyl methacrylate (PMMA), polyethyl methacrylate (PEMA), polyglycidyl methacrylate (PGMA) and other common polymethacrylate series plastics; 6) polyurethane plastics, including polyurethane, polyaminoacetate and other common polyurethane (PU) plastics; 7) copolymer plastics, including ethylene-octene copolymer (POE), ethylene-vinyl acetate copolymer (EVA), styrene-acrylonitrile copolymer (SAN) and other general copolymer plastic materials. The types of polymer plastic materials that can be modified by the fluorescent molecule include but are not limited to the types of plastics mentioned in the above examples, and common general plastic materials are applicable.

[0097] In one embodiment of the present invention, the amount of fluorescent molecules added is 0.01 wt% to 10 wt% based on the mass of the polymer, but is not limited to this amount, and the fluorescence intensity varies with the amount added.

[0098] In one embodiment of the present invention, the universal fluorescent molecule is used to modify the polymer (solution method), which comprises the following steps: dissolving the polymer and the fluorescent molecule in an organic solvent, stirring evenly, and then volatilizing the organic solvent to obtain a mixture of the fluorescent molecule and the polymer, and modifying at 120°C to 160°C for 2 hours to obtain the modified polymer.

[0099] In one embodiment of the present invention, the modification of polyolefin polymers by the universal fluorescent molecule (bulk method) comprises the following steps: adding polymer particles to an internal mixer at 180°C to 220°C, with a rotor speed of 50 rpm, and waiting for the polymer particles to be completely melted, adding fluorescent molecules in different proportions, and reacting for 30 minutes to obtain the modified polymer.

[0100] In one embodiment of the present invention, for the modification of polyolefin polymers with the universal fluorescent molecules (extrusion method), the polymer particles, fluorescent molecules, and antioxidants are pre-mixed, and the temperature of the twin-screw extruder is set and the speed is set to 50 rpm; the twin-screw extruder is first cleaned with high-density polyethylene, and after cleaning, the mixed particles are added to carry out an extrusion experiment; the obtained wire is pelletized with a pelletizer to obtain the modified polymer.

[0101] In one embodiment of the present invention, the polymer modified with the universal fluorescent molecule is used for polymer sorting, which is achieved by the following method: the modified polymer is mixed with other unmodified polymers, and the polymers can be classified by infrared plus fluorescence. First, different types of polymers are distinguished by infrared, and then different types of polymers of the same type are distinguished by fluorescence spectroscopy.

[0102] In one embodiment of the present invention, the universal fluorescent molecule can be made into fluorescent anti-counterfeiting ink to prevent counterfeiting of polymers, comprising the following steps: applying the fluorescent anti-counterfeiting ink to the polymer, heating for 10 minutes at a temperature of 120°C to 160°C, and obtaining a surface anti-counterfeiting polymer. The surface anti-counterfeiting polymer can be distinguished from a conventional polymer (without surface anti-counterfeiting) by fluorescence spectrum.

[0103] Example 1

[0104] A fluorescent molecule containing a diazo group, the structural formula of which is:

[0105]

[0106] The reaction equation of the above fluorescent molecule containing a diazo group is as follows:

[0107]

[0108] 9-Anthracene methanol (2.00 g, 9.60 mmol) and dichloromethane (40 mL) were added to a 100 mL round-bottom flask, and phenylacetyl chloride (2.23 g, 14.40 mmol) and triethylamine (2.92 g, 28.80 mmol) were added dropwise to the reaction solution under ice-water bath conditions. After half an hour of reaction, the room temperature was restored and stirred overnight. After the reaction was completed, a saturated potassium carbonate solution was added to the reaction solution to quench the reaction, and the aqueous phase was extracted three times with dichloromethane, and the obtained organic phase mixture was dried over anhydrous sodium sulfate. After rotary evaporation, the crude product was purified by silica gel column to obtain a light yellow solid product (2.57 g, 82% yield).

[0109] The product obtained in the previous step (2.00 g, 6.16 mmol) and ultra-dry dichloromethane (40 mL) were added to a 100 mL reaction bottle, and p-toluenesulfonyl azide (TsN 3 , 3.23 g, 12.25 mmol) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU, 1.87 g, 12.25 mmol) were added dropwise to the reaction solution, and the corresponding orange product was obtained after 24 hours of reaction. After rotary evaporation, the crude product was purified by silica gel separation column to obtain a dark yellow solid product (1.74 g, 82% yield).

[0110] Example 2

[0111] A fluorescent molecule containing a diazo group, the structural formula of which is:

[0112]

[0113] The reaction equation of the above fluorescent molecule containing a diazo group is as follows:

[0114]

[0115] 1-Naphthol (5.00 g, 34.70 mmol), potassium carbonate (19.30 g, 140.00 mmol), N,N-dimethylformamide (DMF, 100 mL) were added to a 250 mL round-bottom flask, stirred under nitrogen for 0.5 h, and then 2-bromoethanol (6.50 g, 52.05 mmol) was added dropwise, and the mixture was reacted at 100 ° C for 12 h. After cooling to room temperature, the reaction solution was washed with water to remove DMF, and extracted with dichloromethane to obtain a crude product. After rotary evaporation and concentration, the crude product was purified by a silica gel separation column to obtain a yellow-brown oily product (5.92 g, yield 90%).

[0116] The product obtained in the previous step (5.92g, 31mmol) and ultra-dry dichloromethane (50mL) were added to a 250mL reaction bottle, and phenylacetyl chloride (6.98g, 45.00mmol) and triethylamine (9.11g, 90.00mmol) were added dropwise under ice bath conditions. After 30min of reaction, the reaction was restored to room temperature for 12h. After the reaction was completed, a saturated sodium bicarbonate solution was added to quench the reaction. The aqueous phase was extracted three times with dichloromethane, and the resulting solution was dried over anhydrous sodium sulfate. The crude product obtained after rotary evaporation was purified by a silica gel separation column to obtain a light yellow product (8.00g, yield 84%).

[0117] The product obtained in the previous step (5.00 g, 16.32 mmol) and ultra-dry dichloromethane (50 mL) were added to a 250 mL round-bottom flask, and p-toluenesulfonyl azide (TsN 3 , 8.60g, 32.70mmol) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU, 5.00g, 32.60mmol) were added dropwise to the reaction solution, and the corresponding orange product was obtained after 24h of reaction. After rotary evaporation and concentration, the crude reaction product was purified by silica gel separation column to obtain a dark yellow solid product (4.12g, yield 76%).

[0118] Example 3

[0119] A fluorescent molecule containing a diazo group, the structural formula of which is:

[0120]

[0121] The reaction equation of the above fluorescent molecule containing a diazo group is as follows:

[0122]

[0123] The first step was synthesized according to the literature (Zhao, Y.; Kwok, RTK; Lam, JWY; Tang, BZA Highly Fluorescent AIE-Active Theranostic Agent with Anti-Tumor Activity to Specific Cancer Cells. Nanoscale 2016, 8, 12520–12523): Benzophenone (5.46 g, 30 mmol), 4-hydroxybenzophenone (5.70 g, 30 mmol), zinc powder (4.80 g, 72 mmol) and ultra-dry tetrahydrofuran (100 mL) were added to a 250 mL round-bottom flask. Under a nitrogen atmosphere, the mixture was cooled to -78 ° C, titanium tetrachloride was added dropwise to the reaction solution, and the temperature was gradually raised to room temperature and stirred for 0.5 h. The reaction solution was then refluxed for 12 h. The reaction solution was poured into a saturated sodium bicarbonate solution to quench the reaction, tetrahydrofuran was removed by rotary evaporation, and the product was extracted from the water using dichloromethane. After rotary evaporation and concentration, the crude product was purified by silica gel separation column to obtain a white solid product (4.10 g, yield 38%).

[0124] The product obtained in the previous step (4.00g, 11.50mmol), potassium carbonate (6.36g, 46.02mmol), and N,N-dimethylformamide (DMF, 50mL) were added to a 250mL round-bottom flask. Under a nitrogen atmosphere, the mixture was stirred for 0.5h and 2-bromoethanol (2.85g, 23.00mmol) was added dropwise. The mixture was reacted at 100℃ for 12h. After cooling to room temperature, the reaction product was washed with water to remove DMF, and dichloromethane was used to extract the crude product. The crude product was purified by a silica gel separation column to obtain the product. The obtained product and dichloromethane (50mL) were added to a 250mL round-bottom flask, and phenylacetyl chloride (2.67g, 17.25mmol) was added dropwise under ice bath conditions. After stirring for 0.5h, the mixture was gradually heated to room temperature and reacted for 12h. The reaction solution was quenched by adding a saturated sodium bicarbonate solution, extracted with dichloromethane, and dried over anhydrous sodium sulfate. The residue was concentrated by rotary evaporation and purified by silica gel separation column to obtain a light yellow solid (3.90 g, two-step yield 67%).

[0125] The product obtained in the previous step (3.90 g, 7.65 mmol), ultra-dry dichloromethane (50 mL), p-toluenesulfonyl azide (TsN 3 , 4.02 g, 15.30 mmol) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU, 2.30 g, 15.30 mmol) were added to a 250 mL round-bottom flask, and a dark yellow liquid was obtained after 24 h. After rotary evaporation and purification by silica gel separation column, a dark yellow solid (3.50 g, yield 85%) was obtained.

[0126] Example 4

[0127] A fluorescent molecule containing a diazo group, the structural formula of which is:

[0128]

[0129] The reaction equation of the above fluorescent molecule containing a diazo group is as follows:

[0130]

[0131] 4,7-Dibromo-2,1,3-benzothiadiazole (2.00g, 6.8mmol), 4-hydroxymethylphenylboronic acid (1.000g, 6.8mmol), (2.80g, 20.4mmol), tetrakis(triphenylphosphine)palladium (245mg, 0.21mmol), toluene (40mL), ethanol (20mL), and water (10mL) were added to a 250mL three-necked flask. Under a nitrogen atmosphere, reflux for 12h. After cooling to room temperature, the organic solvent was removed by rotary evaporation, and the crude product was extracted with dichloromethane. After rotary evaporation and concentration, it was purified by a silica gel separation column to obtain a light yellow solid product (1.5g, yield 69%).

[0132] The product obtained in the previous step (1.00g, 3.13mmol), methyl malonate chloride (0.40mL, 3.75mmol), and ultra-dry dichloromethane (20mL) were added to a 100mL round-bottom flask. Under an ice bath, triethylamine (0.65mL, 4.68mmol) was added dropwise to the reaction solution. After stirring for 0.5h, the mixture was returned to room temperature and stirred for 12h. The reaction solution was quenched with saturated sodium bicarbonate solution and extracted with dichloromethane. After rotary evaporation and concentration, the product was purified by a silica gel separation column to obtain a light yellow solid (0.9g, yield 68%).

[0133] The product obtained in the previous step (0.50 g, 1.19 mmol), 4-acetamidobenzenesulfonyl azide (0.57 g, 2.38 mmol), and acetonitrile (10 mL) were added to a 100 mL round-bottom flask. Triethylamine (0.65 mL, 4.76 mmol) was added dropwise under ice bath conditions. Stir at room temperature for 24 h. After rotary evaporation and concentration, the product was purified by silica gel separation column to obtain a light yellow solid (0.45 g, yield 70%).

[0134] Example 5

[0135] A fluorescent molecule containing a diazo group, the structural formula of which is:

[0136]

[0137] The reaction equation of the above fluorescent molecule containing a diazo group is as follows:

[0138]

[0139] The product obtained in the first step (1.00 g, 3.13 mmol), tributyl (2-thienyl) tin (1.30 mL, 4.00 mmol), tetrakis (triphenylphosphine) palladium (0.11 g, 0.09 mmol), and toluene (50 mL) were added to a 250 mL round-bottom flask. The mixture was reacted at 100 °C for 12 h under a nitrogen atmosphere. The mixture was concentrated by rotary evaporation and purified by a silica gel separation column to obtain a yellow solid (0.90 g, 90% yield).

[0140] The product obtained in the previous step (0.90g, 2.78mmol), methyl malonate chloride (0.40mL, 3.75mmol), and ultra-dry dichloromethane (20mL) were added to a 100mL round-bottom flask. Under an ice bath, triethylamine (0.65mL, 4.68mmol) was added dropwise to the reaction solution. After stirring for 0.5h, the mixture was returned to room temperature and stirred for 12h. The reaction solution was quenched with saturated sodium bicarbonate solution and extracted with dichloromethane. After rotary evaporation and concentration, the product was purified by a silica gel separation column to obtain a yellow solid (1.00g, yield 85%).

[0141] The product obtained in the previous step (0.42 g, 1.00 mmol), 4-acetylaminobenzenesulfonyl azide (0.48 g, 2 mmol), and acetonitrile (10 mL) were added to a 100 mL round-bottom flask, and triethylamine (0.60 mL, 4 mmol) was added dropwise under ice bath conditions. Stir at room temperature for 24 h. After rotary evaporation and concentration, the product was purified by silica gel separation column to obtain a light yellow solid (0.31 g, yield 70%).

[0142] Example 6

[0143] A fluorescent molecule containing a diazo group, the structural formula of which is:

[0144]

[0145] The reaction equation of the above fluorescent molecule containing a diazo group is as follows:

[0146]

[0147] The product obtained in the first step (1.00 g, 3.13 mmol), 4-triphenylamine borate (1.01 g, 3.50 mmol), tetrakis(triphenylphosphine)palladium (0.11 g, 0.09 mmol), toluene (20 mL), ethanol (10 mL), and water (5 mL) were added to a 100 mL round-bottom flask. The mixture was reacted at 100 °C for 12 h under a nitrogen atmosphere. Toluene and ethanol were removed by rotary evaporation, and the product was extracted with dichloromethane. The product was concentrated by rotary evaporation and purified by a silica gel separation column to obtain a red solid (1.36 g, 90% yield).

[0148] The product obtained in the previous step (1.00g, 2.06mmol), methyl malonate chloride (0.27mL, 2.50mmol), and ultra-dry dichloromethane (50mL) were added to a 100mL round-bottom flask. Under an ice bath, triethylamine (0.86mL, 6.18mmol) was added dropwise to the reaction solution. After stirring for 0.5h, it was returned to room temperature and stirred for 12h. The reaction solution was quenched with saturated sodium bicarbonate solution and extracted with dichloromethane. After rotary evaporation and concentration, it was purified by a silica gel separation column to obtain a red solid (0.96g, yield 80%).

[0149] The product obtained in the previous step (0.59 g, 1.00 mmol), 4-acetylaminobenzenesulfonyl azide (0.48 g, 2 mmol), and acetonitrile (10 mL) were added to a 100 mL round-bottom flask, and triethylamine (0.60 mL, 4 mmol) was added dropwise under ice bath conditions. Stir at room temperature for 24 h. After rotary evaporation and concentration, the product was purified by silica gel separation column to obtain a red solid (0.40 g, yield 66%).

[0150] Example 7

[0151] Solution method to achieve polystyrene (PS) modification:

[0152] Polystyrene modification: Take 10 mg of the fluorescent molecule obtained in Example 1, add 1000 mg of polystyrene, add 5 mL of dichloromethane, stir and dissolve, remove the solvent after the polystyrene and fluorescent molecules are evenly mixed, and react the mixture at 120°C for two hours to obtain a modified polymer. In order to remove the unreacted small molecules, the modified polymer is dissolved in dichloromethane and then precipitated with methanol. The dissolution and precipitation are repeated three times to obtain a pure modified polymer. The NMR spectra of the polymer before and after modification are as follows: Figure 1 The modified polymer has obvious peaks at 4.0ppm and 7.5-8.5ppm, which proves that the modification is successful. At the same time, the modification efficiency of 2.5% can be obtained through NMR integration.

[0153] The same method was used to modify polystyrene with fluorescent molecules in different proportions. The modified polymer was dissolved and precipitated repeatedly three times to obtain a pure modified polymer.

[0154] Preparation of polymer film: The modified polymer is pressed into a film using a flat plate vulcanizer. The temperature of the flat plate vulcanizer is set at 180°C, preheated for 5 minutes, vented 6 times, maintained for 5 minutes, and cold pressed for 5 minutes. The polymer film is obtained.

[0155] Comparative sample preparation: Take 1g of unmodified polystyrene particles and press them into a film using a flat vulcanizer. The flat vulcanizer is set at 180°C, preheated for 5 minutes, vented 6 times, kept for 5 minutes, and cold pressed for 5 minutes. The polymer film is obtained.

[0156] Fluorescence test of modified polymers: The obtained polymer film was cut into 1cm*1cm square films and tested using a high-resolution steady-state fluorescence spectrometer (FLS1000). The fluorescence spectrum was obtained by excitation with 365nm light. The fluorescence spectra of polymers with different modification amounts were the same, such as Figure 2 However, the fluorescence intensity first increases and then decreases with the increase of the added concentration, as shown in Figure 3 As shown. Compared with the control sample, the modified polystyrene has a good luminescence effect. Theoretically, 100ppm to 4000ppm can meet the use requirements. From an economic point of view, 100ppm of fluorescent molecules can be added. If the plastic needs to be further modified or blended with other plastics, it is recommended to increase the concentration appropriately according to the actual situation and needs to ensure the luminescence intensity.

[0157] Thermodynamic test of modified polymer: The thermal properties of the polymer before and after modification were tested using a differential scanning calorimeter (Q2000). Test conditions: nitrogen atmosphere, heating rate 10℃ / min. After the first cycle of heating to 180℃, keep warm for 1min, cool down to 40℃, and heat to 180℃ in the second cycle to measure the glass transition temperature of the polymer. The experimental results are as follows Figure 4 Compared with the control sample, the glass transition temperature of the modified polystyrene has no obvious change.

[0158] Example 8

[0159] Modification of polylactic acid (PLA) by solution method:

[0160] Polylactic acid modification: Take 1g of polylactic acid particles and dissolve them in 20mL of dichloromethane. Take 100mg of the fluorescent molecules synthesized in Example 2 (10% of the polymer mass) and add them to the polymer solution. Stir to evaporate the solvent, heat to 140°C, and keep it for 1h to obtain the modified polymer. In order to remove the unmodified small molecules, the polymer was dissolved and precipitated with dichloromethane and methanol for 3 times, and dried to constant weight to obtain a clean polymer.

[0161] Preparation of polymer film: The modified polymer is pressed into a film using a flat vulcanizer. The temperature of the flat vulcanizer is set at 100°C, preheated for 5 minutes, vented 6 times, kept for 5 minutes, and cold pressed for 5 minutes. The polymer film is obtained.

[0162] Fluorescence test of modified polymers: The obtained polymer film was cut into 1cm*1cm square films and tested using a high-resolution steady-state fluorescence spectrometer (FLS1000). For polylactic acid modified with different fluorescent molecules, the fluorescence spectrum can be obtained by using excitation light of different wavelengths.

[0163] Example 9

[0164] Modification of high-density polyethylene (HDPE) by bulk method:

[0165] High-density polyethylene modification: High-density polyethylene was modified by using an internal mixer. When the internal mixer was heated to 180°C and the rotor speed was 50 r / min, 44 g of high-density polyethylene particles and 44 mg of the fluorescent molecules of Example 3 (the amount was 0.1% of the polymer mass) were added, and the reaction was continued for 30 minutes to obtain the modified high-density polyethylene.

[0166] Preparation of high-density polyethylene sheet: The modified polymer is pressed into a sheet using a flat vulcanizer. Take 8g of the modified high-density polyethylene sample and put it into a 10cm*10cm*1mm square compression mold, and put the mold and the material into the flat vulcanizer together. Set the temperature of the flat vulcanizer to 180℃, preheat for 5 minutes, exhaust 6 times, keep for 5 minutes, and cold press for 5 minutes. The high-density polyethylene sheet (HDPE-M) is obtained.

[0167] Comparative sample preparation: Take 8g of high-density polyethylene particles and put them into a 10cm*10cm*1mm square compression mold, and put the mold and the material into a flat vulcanizer. Set the temperature of the flat vulcanizer to 180℃, preheat for 5 minutes, exhaust 6 times, keep for 5 minutes, and cold press for 5 minutes. This is the high-density polyethylene sheet (HDPE).

[0168] The actual pictures of high-density polyethylene sheets before and after modification are as follows Figure 5 There is no obvious difference to the naked eye, but under ultraviolet light, the modified high-density polyethylene has obvious luminescence, which is in sharp contrast with the unmodified high-density polyethylene.

[0169] Fluorescence test of modified high-density polyethylene: The obtained polymer sheet was cut into 1cm*1cm square sheets and tested using a high-resolution steady-state fluorescence spectrometer (FLS1000). The fluorescence spectrum was obtained by using 365nm light excitation, such as Figure 5Compared with the unmodified high-density polyethylene sheet, the modified high-density polyethylene has an obvious luminescence effect.

[0170] Tensile test of high-density polyethylene before and after modification: The obtained polymer sheet was cut into dumbbell shape using a dumbbell cutter. A universal electronic testing machine (Instron 5966) was used. The tensile rate was 1 mm / min at room temperature, and the average value was obtained by three tests. Figure 6 Compared with the control sample, the mechanical properties of the modified high-density polyethylene have no obvious changes.

[0171] Example 10

[0172] Modification of polypropylene (PP) by bulk method:

[0173] Modification of polypropylene: Polypropylene was modified by using an internal mixer. The internal mixer was set at 180°C and the rotor speed was 50 r / min. Pre-mixed polypropylene particles (50 g) and 5 mg of the fluorescent molecule containing a diazo group prepared in Example 4 were added (the amount was 0.01% of the polymer mass). The reaction was continued for 30 minutes to obtain the modified polypropylene.

[0174] Preparation of polypropylene sheet: The modified polypropylene is pressed into a sheet using a flat vulcanizer. Take 8g of the modified polypropylene sample and put it into a 10cm*10cm*1mm square compression mold, and put the mold and the material into the flat vulcanizer together. Set the temperature of the flat vulcanizer to 180℃, preheat for 5 minutes, exhaust 6 times, keep for 5 minutes, and cold press for 5 minutes. The modified polypropylene sheet is obtained.

[0175] Comparative sample preparation: Take 8g of polypropylene particles and put them into a 10cm*10cm*1mm square compression mold, and put the mold and the material into a flat vulcanizer. Set the temperature of the flat vulcanizer to 180℃, preheat for 5min, exhaust 6 times, keep for 5min, and cold press for 5min. The polypropylene sheet is obtained.

[0176] Fluorescence test of polypropylene sheet: The obtained polymer sheet is cut into 1cm*1cm square sheets and tested using a high-resolution steady-state fluorescence spectrometer (FLS1000) to obtain the fluorescence spectrum. Different fluorescent molecules need to be modified with different excitation lights. Compared with the control sample, the modified polypropylene has a significant luminescence effect.

[0177] Polypropylene mechanical properties test: The obtained polymer sheet was cut into dumbbell shape with a dumbbell cutter. A universal electronic testing machine (Instron 5966) was used. The tensile rate was 1mm / min at room temperature, and the average value was obtained by three tests. Compared with the control sample, the mechanical properties of the modified high-density polyethylene did not change significantly.

[0178] Embodiment 11

[0179] ABS modification using twin-screw extruder:

[0180] ABS was modified by a twin-screw extruder: ABS particles (50 g), 500 mg of the fluorescent molecules of Example 3 (1% of the mass of ABS), and antioxidant 1010 (1% of the mass of ABS) were pre-mixed. The preset temperatures of the twin-screw extruder were: 160°C, 200°C, 240°C, 240°C, 240°C, 240°C, 240°C, 240°C (from the feed port to the discharge port), and the speed was set to 50 rpm. The twin-screw extruder was first cleaned with high-density polyethylene. After cleaning, the mixed particles were added for extrusion experiments. The obtained wire was pelletized with a pelletizer to obtain the modified ABS.

[0181] Preparation of ABS sheet: The modified ABS is pressed into a sheet using a flat vulcanizer. Take 10g of the modified polypropylene sample and put it into a 10cm*10cm*1mm square compression mold, and put the mold and the material into the flat vulcanizer together. Set the temperature of the flat vulcanizer to 240℃, preheat for 15min, exhaust 6 times, keep for 5min, and cold press for 5min. The modified ABS sheet is obtained.

[0182] Comparative sample preparation: Take 10g of ABS particles and put them into a 10cm*10cm*1mm square compression mold, and put the mold and the material into a flat vulcanizer. Set the temperature of the flat vulcanizer to 240℃, preheat for 15min, exhaust 6 times, keep for 5min, and cold press for 5min. The ABS sheet is obtained.

[0183] ABS sheet fluorescence test: The obtained polymer sheet was cut into 1cm*1cm square sheets and tested using a high-resolution steady-state fluorescence spectrometer (FLS1000) to obtain the fluorescence spectrum. Different fluorescent molecules need to be modified with different excitation lights. Compared with the control sample, the modified ABS has a significant luminescence effect.

[0184] ABS mechanical properties test: The obtained polymer sheet was cut into dumbbell shape with a dumbbell cutter. A universal electronic testing machine (Instron 5966) was used. The tensile rate was 1mm / min at room temperature, and the average value was obtained after three tests. Compared with the control sample, the mechanical properties of the modified ABS did not change significantly.

[0185] Example 12

[0186] Modification of ABS / PC plastic alloy using twin-screw extruder:

[0187] Twin-screw extruder to modify ABS / PC: ABS / PC particles (50g), 500mg of the fluorescent molecules of Example 6 (1% of the mass of ABS / PC), and antioxidant 1010 (1% of the mass of ABS / PC) are pre-mixed. The preset temperatures of the twin-screw extruder are: 160°C, 200°C, 240°C, 240°C, 240°C, 240°C, 200°C (from the feed port to the discharge port), and the speed is set to 80rpm. First, clean the twin-screw extruder with high-density polyethylene. After cleaning, add the mixed particles for extrusion experiments. The obtained wire is pelletized with a pelletizer to obtain the modified ABS / PC.

[0188] Preparation of ABS / PC sheet: The modified ABS / PC is pressed into a sheet using a flat vulcanizer. Take 10g of the modified polypropylene sample and put it into a 10cm*10cm*1mm square compression mold, and put the mold and the material into the flat vulcanizer together. Set the temperature of the flat vulcanizer to 220℃, preheat for 15min, exhaust 6 times, keep for 5min, and cold press for 5min. The modified ABS sheet is obtained.

[0189] Comparative sample preparation: Take 10g of ABS / PC particles and put them into a 10cm*10cm*1mm square compression mold. Put the mold and the material into a flat vulcanizer. Set the temperature of the flat vulcanizer to 220℃, preheat for 15min, exhaust 6 times, keep for 5min, and cold press for 5min. You can get the ABS / PC sheet.

[0190] ABS / PC sheet fluorescence test: The obtained polymer sheet was cut into 1cm*1cm square sheets and tested using a high-resolution steady-state fluorescence spectrometer (FLS1000) to obtain the fluorescence spectrum. Different fluorescent molecules need to be modified with different excitation lights. Compared with the control sample, the modified ABS has a significant luminescence effect.

[0191] ABS / PC mechanical properties test: The obtained polymer sheet was cut into dumbbell shape with a dumbbell cutter. A universal electronic testing machine (Instron 5966) was used. The tensile rate was 1mm / min at room temperature, and the average value was obtained by three tests. Compared with the control sample, the mechanical properties of the modified ABS / PC did not change significantly.

[0192] Embodiment 13

[0193] Modification of PP using twin-screw extruder:

[0194] The twin-screw extruder is used to modify PP: PP particles (50 g), 50 mg of the fluorescent molecules of Example 6 (0.1% of the mass of PP), and antioxidant 1010 (1% of the mass of PP) are pre-mixed. The preset temperatures of the twin-screw extruder are: 140°C, 160°C, 200°C, 200°C, 200°C, 200°C, 200°C, 200°C (from the feed port to the discharge port), and the speed is set to 100 rpm. The twin-screw extruder is first cleaned with high-density polyethylene. After cleaning, the mixed particles are added for extrusion experiments. The obtained wire is pelletized with a pelletizer to obtain the modified ABS / PC.

[0195] Preparation of PP sheet: The modified PP is pressed into a sheet using a flat vulcanizer. Take 8g of the modified polypropylene sample and put it into a 10cm*10cm*1mm square compression mold, and put the mold and the material into the flat vulcanizer together. Set the temperature of the flat vulcanizer to 180℃, preheat for 15 minutes, exhaust 6 times, keep for 5 minutes, and cold press for 5 minutes. The modified ABS sheet is obtained.

[0196] Comparative sample preparation: Take 10g of PP particles and put them into a 10cm*10cm*1mm square compression mold, and put the mold and the material into a flat vulcanizer. Set the temperature of the flat vulcanizer to 180℃, preheat for 15min, exhaust 6 times, keep for 5min, and cold press for 5min. The PP sheet is obtained.

[0197] PP sheet fluorescence test: The obtained polymer sheet was cut into 1cm*1cm square sheets and tested using a high-resolution steady-state fluorescence spectrometer (FLS1000) to obtain the fluorescence spectrum. Different fluorescent molecules need to be modified with different excitation lights. Compared with the control sample, the modified PP has a significant luminescence effect.

[0198] PP mechanical properties test: The obtained polymer sheet was cut into dumbbell shape with a dumbbell cutter. A universal electronic testing machine (Instron 5966) was used. The tensile rate was 1mm / min at room temperature, and the average value was obtained after three tests. Compared with the control sample, the mechanical properties of the modified PP did not change significantly.

[0199] Embodiment 14

[0200] Modified fluorescent polymers for polymer screening:

[0201] Modified fluorescent polymers are used for polymer tracking and sorting. Modified polymers and unmodified polymers of different types are mixed together. Different types of polymers are first distinguished by infrared, and then different grades of polymers of the same type are sorted by fluorescence spectroscopy.

[0202] Embodiment 15

[0203] Fluorescent molecules are used as polymer anti-counterfeiting ink:

[0204] Fluorescent molecules are used as anti-counterfeiting inks to treat the surface of polymers. Synthesized fluorescent molecules containing diazo groups can be dissolved in organic solvents, applied to the surface of polymers, and heated to 120-160°C to obtain polymers with fluorescent patterns, which can display colors and patterns under the stimulation of specific excitation light.

[0205] It can be seen from the above experiments that the fluorescent molecules of the present invention can be used to modify general polymers. The modified polymers have strong fluorescent properties while maintaining their original thermal and mechanical properties.

[0206] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A fluorescent probe for polymer post-modification, characterized in that: It has the general structural formula of formula I, II or III: wherein R1 and R3 are independently selected from hydrogen atom, nitro, phenyl, alkyl, cyano, methoxy or halogen atom; R2, R4 and R5 are independently selected from one or more groups in formula (I) to (XV):

2. A method for preparing a fluorescent probe for polymer post-modification as claimed in claim 1, characterized in that: The steps include: S1: a compound containing an acyl chloride group and an alcohol containing a fluorescent group undergo an esterification reaction under the catalysis of a base to obtain a corresponding ester; S2: reacting the ester obtained in step S1 with an azide compound under the action of DBU or triethylamine to obtain a corresponding fluorescent probe.

3. The method for preparing a fluorescent probe for polymer post-modification according to claim 2, characterized in that: The compound containing an acyl chloride group is phenylacetyl chloride or methyl malonate chloride; the azide compound is p-toluenesulfonyl azide or 4-acetamidobenzenesulfonyl azide.

4. The method for preparing a fluorescent probe for polymer post-modification according to claim 2, characterized in that: In step S1, the compound containing an acyl chloride group is added in excess according to a stoichiometric ratio; In step S2, the azide compound is added according to a stoichiometric ratio or added in excess according to a stoichiometric ratio.

5. A use of a fluorescent probe for polymer post-modification as claimed in claim 1, characterized in that: The fluorescent probe modifies a polymer containing aliphatic carbon-hydrogen bonds, or modifies a polymer containing active hydrogen; the active hydrogen includes hydroxyl, carboxyl and amino.

6. A polymer modified with a fluorescent probe, characterized in that: The polymer containing aliphatic carbon-hydrogen bonds is post-modified by the fluorescent probe as claimed in claim 1; the post-modification methods include solution method, bulk method and extrusion method.

7. A polymer modified with a fluorescent probe according to claim 6, characterized in that: The polymers include polyolefin plastics, polyester plastics, polylactone plastics, polyacrylate plastics, polymethacrylate plastics, polyurethane plastics and copolymer plastics.

8. The polymer modified with a fluorescent probe according to claim 6, characterized in that: The added amount of the fluorescent probe is 0.001-10% of the total mass of the polymer.

9. Use of a polymer modified with a fluorescent probe as claimed in any one of claims 6 to 8 in polymer sorting.

10. Use of a polymer modified with a fluorescent probe as claimed in any one of claims 6 to 8 in polymer anti-counterfeiting.

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