Copolymer microspheres, methods of making and using the same

Abstract

The application relates to the field of polymer synthesis and discloses a copolymer microsphere as well as a preparation method and application thereof. The copolymer microsphere comprises structural unit A, structural unit B and structural unit C, the molar content of the structural unit A is 27-55% based on the total molar content of the copolymer microsphere, the molar content of the structural unit B is 27-55%, and the molar content of the structural unit C is 5-20%. The copolymer microsphere is clean and pollution-free on the surface, the microsphere particles are uniform, the microsphere preparation process is simple, safe and environmentally friendly, and the copolymer microsphere prepared by the method can be used for a photoluminescent material.

Description

Technical Field

[0001] This invention relates to the field of polymer synthesis, and more specifically, to a copolymer microsphere, its preparation method, and its application. Background Technology

[0002] Polymer microspheres containing vinyl acetate are typically prepared via emulsion polymerization. However, the emulsifiers and surfactants present in the polymers obtained through emulsion polymerization can negatively impact their properties.

[0003] Traditional methods for preparing polymer microspheres include emulsion polymerization, suspension polymerization, soap-free emulsion polymerization, dispersion polymerization, and precipitation polymerization. Emulsion polymerization, suspension polymerization, and dispersion polymerization typically require the addition of emulsifiers, stabilizers, and other additives to the reaction system to achieve the preparation of polymer microspheres and their stability in the dispersion medium. These additives can have negative effects in certain applications and need to be removed. Soap-free emulsion polymerization and precipitation polymerization can prepare polymer microspheres without the addition of external stabilizing agents. Soap-free emulsion polymerization is usually carried out in an aqueous system and requires the participation of special initiators or comonomers to achieve the preparation and stabilization of microspheres (Liu Min, Hou Lihua, Zhang Shuxiang. Soap-free emulsion polymerization and characterization of VAc / NaAA / EGMAG, Journal of Qingdao University of Science and Technology: Natural Science Edition, 2012, 33(03):251-254). Precipitation polymerization is another polymerization method for preparing polymer microspheres. Traditional precipitation polymerization usually involves a low concentration of monomers, resulting in low efficiency in preparing polymer microspheres. Self-stabilizing precipitation polymerization is a novel method for preparing polymer microspheres. The choice of dispersion medium is crucial to the formation, morphology, particle size, and stability of the microspheres. Commonly used solvents include mixed solvents of organic acid alkyl esters, ketones and alkanes, or mixed solvents of ketones and other organic media (Chen Dong et al. Principles, Methods and Applications of Self-Stabilizing Precipitation Polymerization, Science in China: Chemistry, 2020, Vol. 50, No. 7: 732-742). The choice of solvent significantly affects the properties of the microspheres and the preparation process, and is also important for process stability and subsequent drying (Zhu Xiaoli et al. Exploring the Boundary Conditions for the Precipitation Polymerization of TMPTA-St in Ethanol-Water Mixed Solvent Based on Hansen Three-Dimensional Solubility Parameters, Acta Polymerica Sinica, 2013, 8: 1099-1107). Ester solvents containing organic acid alkyl esters usually have an odor, and the production environment and the obtained product often contain a certain odor. When using mixed solvents as dispersion media, the composition of the solvent needs to be controlled, which complicates process control and increases manufacturing costs. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems existing in the prior art and to provide a copolymer microsphere, its preparation method and application. The copolymer microsphere has a clean and pollution-free surface and uniform microsphere particles. The microsphere preparation process is simple, safe and environmentally friendly. The copolymer microspheres prepared by this method can be used in photoluminescent materials.

[0005] To achieve the above objectives, a first aspect of the present invention provides a copolymer microsphere comprising structural unit A, structural unit B and structural unit C;

[0006] Among them, structural unit A has the structure shown in formula (1), structural unit B has the structure shown in formula (2), and structural unit C is derived from polyol acrylate compounds;

[0007]

[0008] Wherein, R1 is a C1-C6 straight-chain alkyl or a C3-C6 branched alkyl;

[0009] R2 is H or methyl;

[0010] R3 is either H or F;

[0011] Based on the total molar amount of the copolymer microspheres, the molar content of structural unit A is 27-55%, the molar content of structural unit B is 27-55%, and the molar content of structural unit C is 5-20%.

[0012] A second aspect of the present invention provides a method for preparing copolymer microspheres, the method comprising:

[0013] S1. In a protective atmosphere, monomer A, monomer B, monomer C and initiator are mixed with an organic solvent to form a homogeneous solution;

[0014] S2. After the homogeneous solution undergoes a polymerization reaction to obtain a copolymer emulsion suspension, solid-liquid separation is performed to obtain copolymer microspheres.

[0015] The monomer A has the structure shown in formula (6), the monomer B has the structure shown in formula (7), and the monomer C is a polyol acrylate compound;

[0016]

[0017] Wherein, R1' is a C1-C6 straight-chain alkyl or a C3-C6 branched alkyl;

[0018] R2' is H or methyl;

[0019] R3' is H or F;

[0020] Based on the total molar content of monomers A, B, and C, the molar content of monomer A is 27-55%, the molar content of monomer B is 27-55%, and the molar content of monomer C is 5-20%.

[0021] The third aspect of the present invention provides the application of the copolymer microspheres described in the first aspect of the present invention or the copolymer microspheres prepared by the preparation method described in the second aspect of the present invention in photoluminescent materials.

[0022] Through the above technical solution, the present invention has the following beneficial effects:

[0023] (1) The copolymer microspheres provided by the present invention have three structural units, which can form a three-dimensional network with specific spatial structure and function. Combined with the specific spatial conjugation effect of oxygen-containing atomic clusters, the molecular structure is more stable and the molecular energy is lower. Furthermore, the polymer has a photoluminescence effect.

[0024] (2) This invention, by selecting a specific organic solvent and combining it with a specific amount of monomer, eliminates the need to add any stabilizers or co-stabilizers to the polymerization reaction system during the polymerization process. The resulting copolymer microspheres are uniformly dispersed in the organic solvent, and no aggregation occurs between the microspheres. This overcomes the problems of complex process control and increased manufacturing costs associated with using mixed solvents as dispersion media.

[0025] (3) The copolymer microspheres obtained in this invention are used in photoluminescent materials and can emit visible light when excited by an external light source. Attached Figure Description

[0026] Figure 1 This is a scanning electron microscope image of the copolymer microspheres prepared in Example 1;

[0027] Figure 2 This is the photoluminescence spectrum of the copolymer microspheres prepared in Example 1. Detailed Implementation

[0028] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0029] The first aspect of the present invention provides a copolymer microsphere, the copolymer microsphere comprising structural unit A, structural unit B and structural unit C;

[0030] Among them, structural unit A has the structure shown in formula (1), structural unit B has the structure shown in formula (2), and structural unit C is derived from polyol acrylate compounds;

[0031]

[0032] Wherein, R1 is a C1-C6 straight-chain alkyl or a C3-C6 branched alkyl;

[0033] R2 is H or methyl;

[0034] R3 is either H or F;

[0035] Based on the total molar amount of the copolymer microspheres, the molar content of structural unit A is 27-55%, the molar content of structural unit B is 27-55%, and the molar content of structural unit C is 5-20%.

[0036] The copolymer microspheres provided by this invention have a clean, uncontaminated surface, excellent morphology, and good uniformity. The aforementioned structural units enable oxygen-containing atomic clusters to have specific spatial interactions, thereby giving the polymer a photoluminescent effect.

[0037] Furthermore, R1 is a C1-C4 straight-chain alkyl group or a C3-C4 branched alkyl group.

[0038] Furthermore, based on the total molar amount of the copolymer microspheres, the molar content of structural unit A is 35-48%, the molar content of structural unit B is 35-48%, and the molar content of structural unit C is 8-18%.

[0039] Furthermore, the molar ratio of structural unit A to structural unit B is 0.9-1.1:1.

[0040] According to the present invention, the polyol acrylate compound is selected from the compounds shown in formula (3) and / or formula (4);

[0041]

[0042] Where n, l, m, p, and q are each an independent integer from 1 to 4;

[0043] R4 and R5 are the structures shown in equation (5);

[0044] R6-R9 are each independently the structure shown in formula (5), H or C1-C6 alkyl, wherein at least two of R6-R9 are the structure shown in formula (5);

[0045]

[0046] Among them, R 10 It can be H, methyl, or ethyl.

[0047] In this invention, structural unit C is derived from the above-mentioned compound, which can form spatial cross-linking points between molecular chain segments, and further, enable the copolymer to form a three-dimensional network structure, thereby improving the structural stability of the copolymer microspheres.

[0048] Furthermore, n, l, m, p, and q are each independently 1 or 2.

[0049] Furthermore, R6-R9 are each independently the structure shown in formula (5) or C1-C3 alkyl groups.

[0050] In one specific embodiment of the present invention, the polyol acrylate compound has the structure shown in formula (3), wherein n is 2, R 10 It is a methyl group.

[0051] In one specific embodiment of the present invention, the polyol acrylate compound has the structure shown in formula (4), wherein l, m, p, and q are 1, R6 is methyl, and R7, R8, and R9 have the structure shown in formula (5), wherein R 10 It is a methyl group.

[0052] In one specific embodiment of the present invention, the polyol acrylate compound has the structure shown in formula (4), wherein l, m, p, and q are 1, and R6, R7, R8, and R9 have the structure shown in formula (5), wherein R 10 It is a methyl group.

[0053] According to the present invention, the average particle size of the copolymer microspheres is 300-2000 nm.

[0054] Furthermore, the average particle size of the copolymer microspheres is 400-1800 nm.

[0055] According to the present invention, the particle size distribution coefficient of the copolymer microspheres is 1.001-1.5.

[0056] Furthermore, the particle size distribution coefficient of the copolymer microspheres is 1.001-1.1.

[0057] In this invention, the average particle size or particle size dispersion index of the copolymer microspheres is within the above range, and the polymer microspheres have a uniform morphology. When used in the field of photoluminescence, they can convert excitation light containing ultraviolet wavelengths into visible light.

[0058] A second aspect of the present invention provides a method for preparing copolymer microspheres, the method comprising:

[0059] S1. In a protective atmosphere, monomer A, monomer B, monomer C and initiator are mixed with an organic solvent to form a homogeneous solution;

[0060] S2. After the homogeneous solution undergoes a polymerization reaction to obtain a copolymer emulsion suspension, solid-liquid separation is performed to obtain copolymer microspheres.

[0061] The monomer A has the structure shown in formula (6), the monomer B has the structure shown in formula (7), and the monomer C is a polyol acrylate compound;

[0062]

[0063] Wherein, R1' is a C1-C6 straight-chain alkyl or a C3-C6 branched alkyl;

[0064] R2 is H or methyl;

[0065] R3 is either H or F;

[0066] Based on the total molar content of monomers A, B, and C, the molar content of monomer A is 27-55%, the molar content of monomer B is 27-55%, and the molar content of monomer C is 5-20%.

[0067] In this invention, by combining specific types and amounts of monomers with organic solvents, no stabilizers or co-stabilizers need to be added to the polymerization reaction system during the polymerization process. The polymerization reaction system can form a self-stabilizing system, and the resulting copolymer microspheres are uniformly dispersed in the organic solvent without agglomeration between the microspheres.

[0068] Furthermore, R1' is a C1-C4 straight-chain alkyl group or a C3-C4 branched alkyl group.

[0069] Furthermore, based on the total molar content of monomers A, B, and C, the molar content of monomer A is 35-48%, the molar content of monomer B is 35-48%, and the molar content of monomer C is 8-18%.

[0070] Furthermore, the molar ratio of monomer A to monomer B is 0.9-1.1:1.

[0071] According to the present invention, the polyol acrylate compound is selected from the compounds shown in formula (3) and / or formula (4);

[0072]

[0073] Where n, l, m, p, and q are each an independent integer from 1 to 4;

[0074] R4 and R5 are the structures shown in equation (5);

[0075] R6-R9 are each independently the structure shown in formula (5), H or C1-C6 alkyl, wherein at least two of R6-R9 are the structure shown in formula (5);

[0076]

[0077] Among them, R 10 It can be H, methyl, or ethyl.

[0078] In this invention, monomer C is selected from the above-mentioned compounds, which are used to copolymerize with other monomers to form a spatial network structure in the molecular structure.

[0079] Furthermore, n, l, m, p, and q are each independently 1 or 2.

[0080] Furthermore, R6-R9 are each independently the structure shown in formula (5) or C1-C3 alkyl groups.

[0081] In one specific embodiment of the present invention, the polyol acrylate compound has the structure shown in formula (3), wherein n is 2, R 10 It is a methyl group.

[0082] In one specific embodiment of the present invention, the polyol acrylate compound has the structure shown in formula (4), wherein l, m, p, and q are 1, R6 is methyl, and R7, R8, and R9 have the structure shown in formula (5), wherein R 10 It is a methyl group.

[0083] In one specific embodiment of the present invention, the polyol acrylate compound has the structure shown in formula (4), wherein l, m, p, and q are 1, and R6, R7, R8, and R9 have the structure shown in formula (5), wherein R 10 It is a methyl group.

[0084] According to the present invention, the mass concentration of the monomer is 3-25 wt% based on the total weight of the homogeneous solution.

[0085] In this invention, when the mass concentration of the monomer meets the above-mentioned range, the polymerization reaction is stable and controllable, which is beneficial to obtaining copolymer microspheres with high uniformity.

[0086] Furthermore, the monomer concentration is 8-20 wt% based on the total weight of the homogeneous solution.

[0087] According to the present invention, the initiator is an organic peroxide and / or an azo compound.

[0088] Further, the organic peroxide is selected from at least one of benzoyl peroxide, dicumyl peroxide, ditert-butyl peroxide, dodecyl peroxide, tert-butyl peroxide, diisopropyl peroxide, and dicyclohexyl peroxide.

[0089] Furthermore, the azo compound is selected from azobisisobutyronitrile and / or azobisisoheptanenitrile.

[0090] According to the present invention, the mass concentration of the initiator is 0.1%-7wt% based on the total weight of the monomer and the initiator.

[0091] Furthermore, based on the total weight of the monomer and the initiator, the mass concentration of the initiator is 0.5-3 wt%.

[0092] Furthermore, based on the total weight of the monomer and the initiator, the mass concentration of the initiator is 0.6-2 wt%.

[0093] According to the present invention, the organic solvent has the structure shown in formula (8);

[0094]

[0095] Among them, R 11 H, C1-C4 straight-chain alkyl, C3-C4 branched alkyl, phenyl or benzyl, R 12 For C1-C 10 Straight-chain alkyl or C3-C 10 Branched alkyl groups.

[0096] In this invention, the use of the above-mentioned organic solvents solves the problem of complex process control caused by the use of multiple organic solvents in combination, and at the same time reduces the problem of strong odor caused by solvent volatilization when using organic acid alkyl esters in the preparation of copolymer microspheres.

[0097] Furthermore, R 11 It is a C1-C4 straight-chain alkyl, a C3-C4 branched alkyl, or a phenyl.

[0098] Furthermore, R 12 It is a straight-chain alkyl group of C1-C7 or a branched alkyl group of C3-C7.

[0099] Furthermore, the organic solvent is at least one of dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, methyl butyl carbonate, etc.

[0100] According to the present invention, the polymerization reaction conditions include: a polymerization temperature of 45-120°C and a polymerization time of 3-20 h.

[0101] Furthermore, the polymerization reaction conditions include: a polymerization temperature of 50-90℃ and a polymerization time of 3-12h.

[0102] According to the present invention, the heating method is water bath and / or oil bath heating.

[0103] According to the present invention, there is no particular limitation on the protective atmosphere, which can be provided by conventional protective gases in the prior art.

[0104] Furthermore, the protective gas is nitrogen.

[0105] According to the present invention, the solid-liquid separation method used is filtration and / or centrifugation.

[0106] Furthermore, the solid-liquid separation method used is centrifugation.

[0107] In one specific embodiment of the present invention, when centrifugation is used, the centrifugation speed is 2000-10000 rad / min and the centrifugation time is 5-40 min.

[0108] The third aspect of the present invention provides the application of the copolymer microspheres described in the first aspect of the present invention or the copolymer microspheres prepared by the preparation method described in the second aspect of the present invention in photoluminescent materials.

[0109] The present invention will be described in detail below through embodiments. It should be understood that the following embodiments are only used to further explain and illustrate the content of the present invention, and are not intended to limit the present invention.

[0110] In the following examples, the polymerization yield (C) is calculated according to the following formula. p Perform the calculation:

[0111] C p =Mp×100% / Mm

[0112] Where Mp is the mass of the obtained polymer, in g; and Mm is the total mass of the added monomers, in g.

[0113] The content of each structural unit in the copolymer microspheres was tested and analyzed using the Elementar Analysensysteme GmbH elemental analysis system. The total amount of C, H and O elements in the copolymer microspheres was obtained at a decomposition temperature of 950-1200℃. The relative content of each structural unit in the copolymer microspheres was calculated by the ratio of C, H and O elements in each monomer.

[0114] The morphology and size of the copolymer microspheres were observed and measured using scanning electron microscopy (SEM).

[0115] The particle size distribution of the polymer was measured and calculated using the software Nano Measure on the particles in the SEM images.

[0116] Number-average particle size is,

[0117] Where n is the number of particles, and di is the particle size of the i-th particle;

[0118] The volumetric particle size is,

[0119] Where n is the number of particles, and di is the particle size of the i-th particle;

[0120] The particle size distribution coefficient is P = DwDn.

[0121] The photoluminescence spectrum of the copolymer was measured using a Horiba JY FL-3 fluorescence spectrometer.

[0122] In the following examples, monomer A is maleic anhydride; monomer B is vinyl acetate, vinyl propionate, or vinyl butyrate; and monomer C is ethylene glycol dimethacrylate, trimethylolpropane triacrylate, or pentaerythritol tetramethacrylate, all of which were purchased from Bailingwei Technology Co., Ltd.

[0123] Unless otherwise specified, all reagents and materials used in the following examples were purchased from reputable chemical reagent suppliers and were of analytical purity.

[0124] Example 1

[0125] Monomer A, azobisisobutyronitrile (AIBN), monomer B, monomer C, and organic solvent were added to a 250 mL three-necked flask. After the materials were mixed evenly, nitrogen gas was purged for 20 minutes. The three-necked flask was then placed in a 70 °C water bath and reacted for 10 hours. After the reaction was completed, the resulting polymer emulsion suspension was centrifuged at 5000 rad / min for 20 minutes to obtain copolymer microspheres.

[0126] Example 2

[0127] Monomer A, azobisisobutyronitrile, monomer B, monomer C and organic solvent were added to a 250 mL three-necked flask. After the materials were mixed evenly, nitrogen gas was purged for 20 minutes. The three-necked flask was then placed in a 70 °C water bath and reacted for 6 hours. After the reaction was completed, the resulting polymer emulsion suspension was centrifuged at 5000 rad / min for 20 minutes to obtain copolymer microspheres.

[0128] Example 3

[0129] Monomer A, azobisisobutyronitrile (AIBN), monomer B, monomer C, and organic solvent were added to a 500 mL three-necked flask. After the materials were mixed evenly, nitrogen gas was purged for 20 minutes. The three-necked flask was then placed in a 75 °C water bath and reacted for 9 hours. After the reaction was completed, the resulting polymer emulsion suspension was centrifuged at 5000 rad / min for 20 minutes to obtain copolymer microspheres.

[0130] Examples 4-5

[0131] Monomer A, azobisisobutyronitrile, monomer B, monomer C and organic solvent were added to a 250 mL three-necked flask. After the materials were mixed evenly, nitrogen gas was purged for 20 minutes. The three-necked flask was then placed in a 70 °C water bath and reacted for 5 hours. After the reaction was completed, the resulting polymer emulsion suspension was centrifuged at 5000 rad / min for 20 minutes to obtain copolymer microspheres.

[0132] Examples 6-7

[0133] Monomer A, azobisisobutyronitrile, monomer B, monomer C and organic solvent were added to a 250 mL three-necked flask. After the materials were mixed evenly, nitrogen gas was purged for 20 minutes. The three-necked flask was then placed in a 68 °C water bath and reacted for 12 h. After the reaction was completed, the resulting polymer emulsion suspension was centrifuged at 5000 rad / min for 20 minutes to obtain copolymer microspheres.

[0134] Examples 8-10

[0135] Monomer A, azobisisobutyronitrile (AIBN), monomer B, monomer C, and organic solvent were added to a 250 mL three-necked flask. After the materials were mixed evenly, nitrogen gas was purged for 20 minutes. The three-necked flask was then placed in a 70 °C water bath and reacted for 10 hours. After the reaction was completed, the resulting polymer emulsion suspension was centrifuged at 5000 rad / min for 20 minutes to obtain copolymer microspheres.

[0136] Example 11

[0137] Monomer A, azobisisobutyronitrile (AIBN), monomer B, monomer C, and organic solvent were added to a 250 mL three-necked flask. After the materials were mixed evenly, nitrogen gas was purged for 20 minutes. The three-necked flask was then placed in a 70 °C water bath and reacted for 12 hours. After the reaction was completed, the resulting polymer emulsion suspension was centrifuged at 5000 rad / min for 20 minutes to obtain copolymer microspheres.

[0138] Comparative Examples 1-2

[0139] Monomer A, azobisisobutyronitrile, monomer B, monomer C and organic solvent were added to a 250 mL three-necked flask. After the materials were mixed evenly, nitrogen gas was purged for 20 minutes. The three-necked flask was then placed in a 70 °C water bath and reacted for 12 h. No copolymer microspheres were obtained from the reaction system.

[0140] Table 1

[0141]

[0142]

[0143] Continued from Table 1

[0144]

[0145] Continued from Table 1

[0146]

[0147]

[0148] Table 2

[0149]

[0150] Figure 1 The image shown is a scanning electron microscope image of the copolymer microspheres obtained in Example 1. It can be seen that the copolymer microspheres are uniform in size and the surface of the particles is clean and uncontaminated. Figure 2 The photoluminescence spectrum of the copolymer microspheres obtained in Example 1 shows that the copolymer microspheres have a photoluminescence effect and can emit light at 525-725 nm after absorbing excitation light at 275-500 nm.

[0151] As can be seen from Table 1, the copolymer microspheres prepared by the method of the present invention have a high yield, and as can be seen from Table 2, the obtained copolymer microspheres have uniform particle size.

[0152] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A copolymer microsphere, characterized in that, The copolymer microspheres comprise structural unit A, structural unit B and structural unit C; Among them, structural unit A has the structure shown in formula (1), structural unit B has the structure shown in formula (2), and structural unit C is derived from polyol acrylate compounds; Wherein, R1 is a C1-C6 straight-chain alkyl or a C3-C6 branched alkyl; R2 is H or methyl; R3 is either H or F; Based on the total molar amount of the copolymer microspheres, the molar content of structural unit A is 27-55%, the molar content of structural unit B is 27-55%, and the molar content of structural unit C is 5-20%.

2. The copolymer microspheres according to claim 1, wherein, R1 is a C1-C4 straight-chain alkyl group or a C3-C4 branched alkyl group.

3. The copolymer microspheres according to claim 1 or 2, wherein, Based on the total molar amount of the copolymer microspheres, the molar content of structural unit A is 35-48%, the molar content of structural unit B is 35-48%, and the molar content of structural unit C is 8-18%. Preferably, the molar ratio of structural unit A to structural unit B is 0.9-1.1:

1.

4. The copolymer microspheres according to claim 1 or 2, wherein, The polyol acrylate compounds are selected from the compounds shown in formula (3) and / or formula (4); Where n, l, m, p, and q are each an independent integer from 1 to 4; R4 and R5 are the structures shown in equation (5); R6-R9 are each independently the structure shown in formula (5), H or C1-C6 alkyl, wherein at least two of R6-R9 are the structure shown in formula (5); Among them, R 10 It can be H, methyl, or ethyl.

5. The copolymer microspheres according to claim 1 or 2, wherein, The average particle size of the copolymer microspheres is 300-2000 nm, preferably 400-1800 nm; And / or, the particle size distribution coefficient of the copolymer microspheres is 1.001-1.5, preferably 1.001-1.

1.

6. A method for preparing copolymer microspheres, wherein, The preparation method includes: S1. In a protective atmosphere, the comonomer and initiator are mixed with an organic solvent to form a homogeneous solution; the comonomer includes monomer A, monomer B and monomer C; S2. After the homogeneous solution undergoes a polymerization reaction to obtain a copolymer emulsion suspension, solid-liquid separation is performed to obtain copolymer microspheres. The monomer A has the structure shown in formula (6), the monomer B has the structure shown in formula (7), and the monomer C is a polyol acrylate compound; Wherein, R1' is a C1-C6 straight-chain alkyl or a C3-C6 branched alkyl; R2' is H or methyl; R3' is H or F; Based on the total molar amount of comonomers, the molar content of monomer A is 27-55%, the molar content of monomer B is 27-55%, and the molar content of monomer C is 5-20%.

7. The preparation method according to claim 6, wherein, R1' is a C1-C4 straight-chain alkyl group or a C3-C4 branched alkyl group.

8. The preparation method according to claim 6 or 7, wherein, Based on the total molar content of monomers A, B, and C, the molar content of monomer A is 35-48%, the molar content of monomer B is 35-48%, and the molar content of monomer C is 8-18%. Preferably, the molar ratio of monomer A to monomer B is 0.9-1.1:

1.

9. The preparation method according to claim 6 or 7, wherein, The polyol acrylate compounds are selected from the compounds shown in formula (3) and / or formula (4); Where n, l, m, p, and q are each an independent integer from 1 to 4; R4 and R5 are the structures shown in equation (5); R6-R9 are each independently the structure shown in formula (5), H or C1-C6 alkyl, wherein at least two of R6-R9 are the structure shown in formula (5); Among them, R 10 It can be H, methyl, or ethyl.

10. The preparation method according to claim 6 or 7, wherein, In step S1, the mass concentration of the comonomer is 3-25 wt%, preferably 8-20 wt%, based on the total weight of the homogeneous solution.

11. The preparation method according to claim 6 or 7, wherein, In step S1, the initiator is an organic peroxide and / or an azo compound; Preferably, the mass concentration of the initiator is 0.1%-7 wt%, more preferably 0.5-3 wt%, and more preferably 0.6-2 wt%, based on the total weight of the monomer and the initiator.

12. The preparation method according to claim 6 or 7, wherein, In step S1, the organic solvent has the structure shown in formula (8); Among them, R 11 H, C1-C4 straight-chain alkyl, C3-C4 branched alkyl, phenyl or benzyl, R 12 For C1-C 10 Straight-chain alkyl or C3-C 10 Branched alkyl groups; Preferably, R 11 It is a C1-C4 straight-chain alkyl, a C3-C4 branched alkyl, or a phenyl; R 12 It is a straight-chain alkyl group of C1-C7 or a branched alkyl group of C3-C7.

13. The preparation method according to claim 6 or 7, wherein, In step S2, the polymerization reaction conditions include: a polymerization temperature of 45-120℃, preferably 50-90℃, and a polymerization time of 3-20h, preferably 3-12h. Preferably, the solid-liquid separation method is centrifugation, with a centrifugation speed of 2000-10000 rad / min and a centrifugation time of 5-40 min.

14. The application of a copolymer microsphere according to any one of claims 1-5 or a copolymer microsphere prepared by any one of claims 6-13 in photoluminescent materials.

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