Large-particle-size monodisperse polystyrene-divinylbenzene microsphere and preparation method thereof

Abstract

The invention discloses a large-particle-size monodisperse polystyrene-divinylbenzene microsphere and a preparation method thereof. The preparation method comprises the following steps: uniformly mixing styrene, divinylbenzene and an oil-soluble initiator to prepare a dispersed phase fluid; dissolving a surfactant in deionized water to prepare a continuous phase fluid; respectively introducing the dispersed-phase fluid and the continuous-phase fluid into a two-phase micro-channel of a micro-fluidic chip, and enabling the flow ratio of the dispersed-phase fluid to the continuous-phase fluid to be 1: (1.2-3.5), so as to prepare a microsphere primary product; putting the microsphere primary product into a receiving solution, and blending to enable the volume fraction of the microsphere primary product in the sphere-liquid mixture to be 5%-15%; carrying out polymerization reaction on the ball-liquid mixture in a nitrogen environment, and then carrying out suction filtration to obtain a microsphere intermediate product; and carrying out washing and vacuum drying on the microsphere intermediate product to obtain the large-particle-size polystyrene-divinylbenzene microsphere. The preparation method is simple, reasonable and easy to operate, and the obtained microspheres have the advantages of being adjustable in particle size, good in uniformity, high in strength, good in pressure resistance and the like.

Description

Technical Field

[0001] The invention relates to the technical field of microsphere preparation, in particular to large-diameter monodisperse polystyrene-divinylbenzene microspheres and a preparation method thereof. Background Art

[0002] As a polymer functional material, porous polystyrene-divinylbenzene microspheres have very broad application prospects in the fields of biomedicine, analytical chemistry, catalyst carriers, etc. Monodisperse polystyrene-divinylbenzene microspheres have good physicochemical stability, adsorption, surface activity and reusability. Their application scope covers standard measurement, food chemical industry, medicine, bioengineering, information engineering microelectronics technology and other fields. They are currently the most widely used polymer microspheres. In recent years, polystyrene-divinylbenzene microspheres have been widely used in the fields of biomedicine and biological monitoring, especially in clinical diagnosis, testing, immunotechnology, cells, etc.

[0003] At present, porous polystyrene-divinylbenzene microspheres are usually synthesized on the market by chemical methods such as emulsion polymerization, suspension polymerization, or seed polymerization. Among them, the particle size of porous polystyrene-divinylbenzene microspheres prepared by emulsion polymerization is generally between 100nm and 1μm, and can reach up to 2μm at most; not only is the particle size of the microspheres very small, but the dispersibility of the microspheres is relatively poor. The particle size of porous polystyrene-divinylbenzene microspheres prepared by suspension polymerization is generally between 1 and 100μm. Compared with emulsion polymerization, the particle size of microspheres prepared by suspension polymerization is larger, but the dispersibility of microspheres is also relatively poor. Large-particle-size or even ultra-large-particle-size porous polystyrene-divinylbenzene microspheres can be prepared by seed polymerization and multiple polymerization reactions, but the particle size distribution of the prepared microspheres is extremely wide, that is, the dispersibility of the microspheres is also relatively poor. In short, the dispersibility of the microspheres finally obtained by the three commonly used microsphere preparation methods is relatively poor, and the cost is high, and the cost performance is not good.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] In order to overcome the above-mentioned defects, the present invention provides a large-particle-size monodisperse polystyrene-divinylbenzene microsphere and a preparation method thereof. The preparation method is simple, reasonable and easy to operate. The prepared polystyrene-divinylbenzene microsphere has the advantages of adjustable particle size, good particle size uniformity, high strength, good pressure resistance, large production capacity, wide application field, etc., which well meets the market demand.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a method for preparing large-size monodisperse polystyrene-divinylbenzene microspheres, comprising:

[0007] The formulated amounts of styrene, divinylbenzene and an oil-soluble initiator are uniformly mixed to prepare a dispersed phase fluid; wherein the weight ratio of the styrene to the divinylbenzene is (1.5-3):1;

[0008] A surfactant is provided and dissolved in deionized water to prepare a continuous phase fluid;

[0009] Providing a microfluidic chip, respectively passing the dispersed phase fluid and the continuous phase fluid into the two-phase microchannel of the microfluidic chip, and controlling the flow ratio of the dispersed phase fluid to the continuous phase fluid to be 1:(1.2-3.5) to obtain a primary microsphere product;

[0010] The microspheres are placed in a receiving solution to obtain a ball-liquid mixture; and the volume fraction of the microspheres in the ball-liquid mixture is adjusted to be 5% to 15%;

[0011] The prepared ball-liquid mixture is transferred into a reactor, and a polymerization reaction is carried out at a reaction temperature of 40° C. to 90° C. for 6 to 20 hours under a nitrogen environment; after the polymerization reaction is completed, the microsphere intermediate is obtained by suction filtration;

[0012] The microsphere intermediate product is sequentially washed and vacuum dried to obtain polystyrene-divinylbenzene microspheres with a particle size of 20 to 500 μm and uniform particle size.

[0013] As a further improvement of the present invention, the dispersed phase fluid has the following raw material formula, calculated by weight percentage: 55% to 72% styrene, 25% to 40% divinylbenzene and 0.1% to 10% oil-soluble initiator; wherein the weight ratio of the styrene to the divinylbenzene is (1.5 to 2.5):1.

[0014] As a further improvement of the present invention, the oil-soluble initiator is selected from any one of tert-butyl peroxy-2-ethylhexanoate, azobisisoheptanenitrile and dimethyl azobisisobutyrate.

[0015] As a further improvement of the present invention, the flow ratio of the dispersed phase fluid to the continuous phase fluid is 1:(1.5-3).

[0016] As a further improvement of the present invention, the flow rates of the dispersed phase fluid and the continuous phase fluid are both no greater than 100 μL / min.

[0017] As a further improvement of the present invention, the continuous phase fluid is composed of a mixture of 3% to 8% of a surfactant and the remainder of deionized water, measured by weight percentage; wherein the surfactant is selected from at least two of polyvinyl pyrrolidone, sodium dodecyl sulfate, polyethylene glycol, sodium dodecyl sulfate and polyether F127.

[0018] As a further improvement of the present invention, the surfactant is composed of polyvinyl pyrrolidone and sodium dodecyl sulfate in a weight ratio of 3:2; or, the surfactant is composed of polyethylene glycol and sodium dodecyl sulfate in a weight ratio of 5:1; or, the surfactant is composed of polyethylene glycol, polyvinyl pyrrolidone and sodium dodecyl sulfate in a weight ratio of 1:1:1; or, the surfactant is composed of polyethylene glycol, polyvinyl pyrrolidone and polyether F127 in a weight ratio of 1:1:1.

[0019] As a further improvement of the present invention, the receiving solution adopts a surfactant aqueous solution with a mass percentage concentration of 0.5% to 10%, wherein the solute in the surfactant aqueous solution is selected from any one of polyvinyl pyrrolidone, sodium dodecyl sulfate, sodium dodecyl sulfate, polyethylene glycol and polyether F127.

[0020] As a further improvement of the present invention, the processing parameters of the vacuum drying treatment are: vacuum degree of 0.08Mpa to 0.1Mpa, drying temperature of 40°C to 70°C, and drying time of 6 to 12h.

[0021] The present invention also provides large-diameter monodisperse polystyrene-divinylbenzene microspheres, which are prepared by the preparation method of large-diameter monodisperse polystyrene-divinylbenzene microspheres described in the present invention.

[0022] The beneficial effects of the present invention are as follows: the present invention preferably adopts a preparation method combining microfluidic technology, polymerization reaction technology, vacuum drying technology, etc. to prepare the polystyrene-divinylbenzene microspheres, wherein, ① when the present invention uses microfluidic technology to prepare the primary microsphere product, on the one hand, the raw material formula of the dispersed phase fluid is optimized to achieve the advantages of high strength, pressure resistance / strong pressure bearing performance, etc., so as to ensure that the primary microsphere product is not easily damaged in the subsequent process, thereby ensuring that the microsphere finished product (i.e., the polystyrene-divinylbenzene microsphere) has a good spherical shape and high quality; on the other hand, the flow ratio of the dispersed phase fluid to the continuous phase fluid is optimized, which can achieve a large production capacity of the primary microsphere product. , on the basis of controllable particle size, it can also better ensure that the shear force and surface tension between the dispersed phase fluid and the continuous phase fluid reach the optimal equilibrium state, so as to obtain a microsphere preliminary product with very high particle size uniformity; ② The present invention adopts "first adjusting the volume fraction / volume ratio of the microsphere preliminary product in the ball-liquid mixture to the optimal control value, and then subjecting the microsphere preliminary product to polymerization reaction", which can effectively avoid the deformation and breakage of the microspheres, further ensure that the spherical shape and uniform size of the microsphere finished product are intact, and also improve the quality of the polymerization reaction, thereby improving the quality of the microsphere finished product; ③ The present invention adopts vacuum drying technology to obtain the final microsphere finished product, which can further ensure that the size of the microsphere finished product is not deformed, etc. ④ The preparation method provided by the present invention is simple, reasonable, and easy to operate, and the relevant raw materials are easy to obtain, the cost is not high, and it is more environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a flow chart of the method for preparing large-size monodisperse polystyrene-divinylbenzene microspheres of the present invention;

[0024] Figure 2 The optical microscope images of the polystyrene-divinylbenzene microspheres prepared in Examples 1 to 4 of the present invention; wherein: Figure 2 Figure (a) shows an optical microscope image of the polystyrene-divinylbenzene microspheres obtained in Example 1; Figure (b) shows an optical microscope image of the polystyrene-divinylbenzene microspheres obtained in Example 2; Figure (c) shows an optical microscope image of the polystyrene-divinylbenzene microspheres obtained in Example 3; Figure (d) shows an optical microscope image of the polystyrene-divinylbenzene microspheres obtained in Example 4;

[0025] Figure 3 is a size distribution diagram of the polystyrene-divinylbenzene microspheres prepared in Examples 1 and 2 of the present invention; wherein, Figure 3 Figure (a) shows the size distribution diagram of the polystyrene-divinylbenzene microspheres described in Example 1; Figure (b) shows the size distribution diagram of the polystyrene-divinylbenzene microspheres described in Example 2;

[0026] Figure 4 This is a size distribution diagram of the polystyrene-divinylbenzene microspheres prepared in Examples 3 to 4 of the present invention; wherein, Figure 4 Figure (a) shows the size distribution diagram of the polystyrene-divinylbenzene microspheres described in Example 3; Figure (b) shows the size distribution diagram of the polystyrene-divinylbenzene microspheres described in Example 4. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below with reference to specific embodiments, but the present invention is not limited to these embodiments.

[0028] The present invention discloses a large-particle-size monodisperse polystyrene-divinylbenzene microsphere and a preparation method thereof. The preparation method is simple, reasonable and easy to operate. The prepared polystyrene-divinylbenzene microsphere has the advantages of adjustable particle size, good particle size uniformity, high strength, good pressure resistance, large production capacity, wide application field, etc., which well meets the market demand. The reason for its realization is mainly that the present invention optimizes and innovates the preparation method and raw material formula of the polystyrene-divinylbenzene microsphere. The specific description is as follows:

[0029] 1. Prepare the polymer emulsion microspheres described in this application;

[0030] Embodiment 1:

[0031] This embodiment 1 provides a method for preparing large-size monodisperse polystyrene-divinylbenzene microspheres, which mainly includes the following steps:

[0032] S1: providing styrene, divinylbenzene (used as a cross-linking agent) and an oil-soluble initiator, wherein the styrene and the divinylbenzene are both of analytical grade, and the oil-soluble initiator is tert-butyl peroxy-2-ethylhexanoate TBPO.

[0033] By weight percentage, 55% by weight of styrene, 36% by weight of divinylbenzene and 9% by weight of tert-butyl peroxy-2-ethylhexanoate TBPO were uniformly mixed to prepare a dispersed phase fluid.

[0034] Note: In the preparation of the dispersed phase fluid in Example 1, the weight ratio of the styrene to the divinylbenzene is optimally controlled to be 1.528:1. By adding the above preferred amount of divinylbenzene, on the one hand, the strength of the primary microspheres can be effectively enhanced, so that the microspheres are not easily broken during subsequent polymerization reactions, washing and other processes, thereby ensuring that the microspheres have a good shape and high quality; on the other hand, the pressure resistance / pressure bearing performance of the primary microspheres can be effectively enhanced, so that the primary microspheres / microsphere finished products have a wider range of applications; in addition, it can also help to increase the maximum flow rate of the dispersed phase fluid in the microfluidic chip, thereby increasing the ball yield.

[0035] S2: providing a surfactant, wherein the surfactant is composed of polyvinyl pyrrolidone (PVP) and sodium lauryl sulfate (SLS) in a weight ratio of 3:2.

[0036] By weight percentage, 5 weight percent of the surfactant and 95 weight percent of deionized water are uniformly mixed to prepare a continuous phase fluid.

[0037] Note: This application does not impose any restrictions on the specific processing order of the dispersed phase fluid and the continuous phase fluid. The two fluids can be processed and prepared at the same time, or in a sequence, and the sequence is not unique.

[0038] S3: Provide a microfluidic chip. This embodiment 1 does not impose any restrictions on the specific structure / type of the microfluidic chip. A microfluidic chip of appropriate specifications can be selected according to product processing requirements. For example, in this embodiment 1, a single cross-focusing microfluidic chip is preferably used, and the specification parameters of the single cross-focusing microfluidic chip are: the diameter of the inner phase microchannel is 50 to 900 μm, and the liquid flow rate flowing in the inner phase microchannel can be controlled at 1 μL / min to 100 μL / min; the diameter of the outer phase microchannel is 200 to 1500 μm, and the liquid flow rate flowing in the outer phase microchannel can also be controlled at 1 μL / min to 100 μL / min. Note: The liquid flow rate can be controlled by adjusting the air pressure in the inner and outer phase microchannels. This is a conventional technical means in the field of microfluidic chip technology, so it will not be described in detail here. However, it should be noted that the specific flow value / flow ratio that can be achieved by the dispersed phase fluid and the continuous phase fluid in the microfluidic chip in Example 1 is one of the important protection points of this application.

[0039] The dispersed phase fluid prepared by S1 and the continuous phase fluid prepared by S2 are respectively introduced into the two-phase microchannels of the microfluidic chip, that is, the dispersed phase fluid is introduced into the inner phase microchannel of the microfluidic chip, and the continuous phase fluid is introduced into the outer phase microchannel of the microfluidic chip; and the flow ratio of the dispersed phase fluid to the continuous phase fluid is controlled to be 1:2.67 (approximately), specifically, the flow rate of the dispersed phase fluid is 3 μL / min, and the flow rate of the continuous phase fluid is 8 μL / min; by utilizing the shearing operation of the fluid, a primary product of microspheres with large production capacity and uniform particle size is obtained.

[0040] S4: firstly placing the microsphere preliminary product in a receiving solution to obtain a ball-liquid mixture; wherein the receiving solution can preferably be a polyvinyl pyrrolidone (PVP) aqueous solution with a mass percentage concentration of 5% to further activate the surface of the microsphere preliminary product and reduce the surface tension; then by adjusting the weight percentage of the receiving solution relative to the ball-liquid mixture (i.e., adding a certain amount of the receiving solution), the volume fraction of the microsphere preliminary product in the ball-liquid mixture is 5% to 15% (preferably about 10%); to ensure that the microspheres are intact and uniform in size, and to ensure the quality of the following polymerization reaction.

[0041] By optimizing the volume fraction / volume ratio of the microsphere primary product in the ball-liquid mixture, the microsphere primary product can be well dispersed in the ball-liquid mixture, that is, the collision between the microsphere primary products is reduced, thereby avoiding adhesion between the microsphere primary products during the subsequent polymerization reaction, reducing the deformation and breakage of the microspheres, ensuring that the spherical shape and uniform size of the microsphere finished product are intact, and improving the quality of the microsphere finished product (the polystyrene-divinylbenzene microsphere).

[0042] S5: The prepared ball-liquid mixture is transferred to a reactor (a four-mouth reactor can be used), and a polymerization reaction is carried out at a reaction temperature of 80°C for 9 hours under a nitrogen environment; after the polymerization reaction is completed, a microsphere intermediate product is obtained by suction filtration using a Buchner funnel. It can be understood that the quality of microsphere molding (i.e., microsphere intermediate product, and even polystyrene-divinylbenzene microsphere finished product) can be further improved through the polymerization reaction.

[0043] S6: First, wash the microsphere intermediate repeatedly with deionized water and / or ethanol for multiple times to remove the receiving solution remaining on the surface of the microsphere intermediate; then place the microsphere intermediate under vacuum conditions of 0.08Mpa~0.1Mpa and 40℃~70℃ for vacuum drying for 6~12h (the optimal process conditions are vacuum degree 0.1Mpa, drying temperature 70℃, and drying time 10h); polystyrene-divinylbenzene microspheres with a spherical shape, an average particle size of 30.28μm, and uniform particle size (CV value of 4.9%) can be obtained.

[0044] Embodiment 2:

[0045] This embodiment 2 also provides a method for preparing large-size monodisperse polystyrene-divinylbenzene microspheres, which mainly includes the following steps:

[0046] S1: providing styrene, divinylbenzene (used as a cross-linking agent) and an oil-soluble initiator, wherein the styrene and the divinylbenzene are both of analytical grade, and the oil-soluble initiator is tert-butyl peroxy-2-ethylhexanoate TBPO.

[0047] By weight percentage, 60% by weight of styrene, 32% by weight of divinylbenzene and 8% by weight of tert-butyl peroxy-2-ethylhexanoate TBPO were uniformly mixed to prepare a dispersed phase fluid.

[0048] Note: In the preparation of the dispersed phase fluid in this embodiment 2, the weight ratio of the styrene to the divinylbenzene is preferably controlled to be 1.875:1. Similar to the above embodiment 1, this embodiment 2 can also effectively enhance the strength, pressure resistance / pressure bearing performance, ball yield, etc. of the microsphere primary product by adding the above preferred amount of divinylbenzene.

[0049] S2: providing a surfactant, wherein the surfactant is composed of polyethylene glycol PEG and sodium dodecyl sulfate SDS in a weight ratio of 5:1.

[0050] By weight percentage, 6% by weight of the surfactant and 94% by weight of deionized water are uniformly mixed to prepare a continuous phase fluid.

[0051] Note: Similar to the above-mentioned embodiment 1, this embodiment 2 also does not impose any restrictions on the specific processing order of the dispersed phase fluid and the continuous phase fluid.

[0052] S3: Provide a microfluidic chip. The structure / type of the microfluidic chip used in this embodiment 2 is the same as that of the microfluidic chip used in the above embodiment 1, so it will not be described here.

[0053] The dispersed phase fluid prepared in S1 is introduced into the inner phase microchannel of the microfluidic chip, and the continuous phase fluid prepared in S2 is introduced into the outer phase microchannel of the microfluidic chip; and the flow ratio of the dispersed phase fluid to the continuous phase fluid is controlled to be 1:1.7, specifically: the flow rate of the dispersed phase fluid is 10 μL / min, and the flow rate of the continuous phase fluid is 17 μL / min; by utilizing the shearing operation of the fluid, a primary microsphere product with large production capacity and uniform particle size is obtained.

[0054] S4: First, the microspheres are placed in a receiving solution to obtain a ball-liquid mixture; wherein the receiving solution can preferably be a polyethylene glycol (PEG) aqueous solution with a mass percentage concentration of 6% to further activate the surface of the microspheres and reduce the surface tension; then, the weight percentage of the receiving solution relative to the ball-liquid mixture is adjusted (i.e., a certain amount of the receiving solution is added) so that the volume fraction of the microspheres in the ball-liquid mixture is 5% to 15% (preferably about 8%); to ensure that the microspheres are intact and uniform in size, and to ensure the quality of the following polymerization reaction.

[0055] Similar to the above-mentioned embodiment 1, the present embodiment 2 optimizes the volume fraction / volume ratio of the microsphere preliminary product in the ball-liquid mixture, so that the microsphere preliminary product can be well dispersed in the ball-liquid mixture, thereby avoiding adhesion between the microsphere preliminary products during the subsequent polymerization reaction, reducing the deformation and breakage of the microspheres, and improving the quality of the microsphere finished product (the polystyrene-divinylbenzene microspheres).

[0056] S5: The prepared ball-liquid mixture is transferred to a reactor (a four-mouth reactor can be used), and a polymerization reaction is carried out at a reaction temperature of 70° C. for 10 hours under a nitrogen environment; after the polymerization reaction is completed, a microsphere intermediate product is obtained by filtration using a Buchner funnel.

[0057] S6: First, wash the microsphere intermediate repeatedly with deionized water and / or ethanol for multiple times to remove the receiving solution remaining on the surface of the microsphere intermediate; then place the microsphere intermediate under vacuum conditions of 0.08Mpa~0.1Mpa and 40℃~70℃ for vacuum drying for 6~12h (the optimal process conditions are vacuum degree 0.1Mpa, drying temperature 70℃, and drying time 8h); polystyrene-divinylbenzene microspheres with a spherical shape, an average particle size of 49.76μm, and uniform particle size (CV value of 4.5%) can be obtained.

[0058] Embodiment 3:

[0059] This embodiment 3 also provides a method for preparing large-size monodisperse polystyrene-divinylbenzene microspheres, which mainly includes the following steps:

[0060] S1: providing styrene, divinylbenzene (used as a cross-linking agent) and an oil-soluble initiator, wherein the styrene and the divinylbenzene are both of analytical grade, and the oil-soluble initiator is azobisisoheptanenitrile ABVN.

[0061] By weight percentage, 65% by weight of styrene, 32.5% by weight of divinylbenzene and 2.5% by weight of azobisisoheptanenitrile ABVN were uniformly mixed to prepare a dispersed phase fluid.

[0062] Note: In the preparation of the dispersed phase fluid in this embodiment 3, the weight ratio of the styrene to the divinylbenzene is preferably controlled to be 2:1. Similar to the above embodiment 1, this embodiment 3 can also effectively enhance the strength, pressure resistance / pressure bearing performance, ball yield, etc. of the microsphere primary product by adding the above preferred amount of divinylbenzene.

[0063] S2: providing a surfactant, wherein the surfactant is composed of polyethylene glycol PEG, polyvinyl pyrrolidone PVP and sodium dodecyl sulfate SDS in a weight ratio of 1:1:1.

[0064] By weight percentage, 6% by weight of the surfactant and 94% by weight of deionized water were uniformly mixed to prepare a continuous phase fluid.

[0065] Note: Similar to the above-mentioned embodiment 1, this embodiment 3 also does not impose any restrictions on the specific processing order of the dispersed phase fluid and the continuous phase fluid.

[0066] S3: Provide a microfluidic chip. The structure / type of the microfluidic chip used in this embodiment 3 is the same as that of the microfluidic chip used in the above embodiment 1, so it will not be described here.

[0067] The dispersed phase fluid prepared by S1 is introduced into the inner phase microchannel of the microfluidic chip, and the continuous phase fluid prepared by S2 is introduced into the outer phase microchannel of the microfluidic chip; and the flow ratio of the dispersed phase fluid to the continuous phase fluid is controlled to be 1:1.57 (approximately), specifically: the flow rate of the dispersed phase fluid is 35 μL / min, and the flow rate of the continuous phase fluid is 55 μL / min; by utilizing the shearing operation of the fluid, a primary microsphere with large production capacity and uniform particle size is obtained.

[0068] S4: First, the microspheres are placed in a receiving solution to obtain a ball-liquid mixture; wherein the receiving solution can preferably be a polyethylene glycol (PEG) aqueous solution with a mass percentage concentration of 6% to further activate the surface of the microspheres and reduce the surface tension; then, the weight percentage of the receiving solution relative to the ball-liquid mixture is adjusted (i.e., a certain amount of the receiving solution is added) so that the volume fraction of the microspheres in the ball-liquid mixture is 5% to 15% (preferably about 12%); to ensure that the microspheres are intact and uniform in size, and to ensure the quality of the following polymerization reaction.

[0069] Similar to the above-mentioned embodiment 1, the present embodiment 3 optimizes the volume fraction / volume ratio of the microsphere preliminary product in the ball-liquid mixture, so that the microsphere preliminary product can be well dispersed in the ball-liquid mixture, thereby avoiding adhesion between the microsphere preliminary products during the subsequent polymerization reaction, reducing the deformation and breakage of the microspheres, and improving the quality of the microsphere finished product (the polystyrene-divinylbenzene microspheres).

[0070] S5: The prepared ball-liquid mixture is transferred to a reactor (a four-mouth reactor can be used), and a polymerization reaction is carried out at a reaction temperature of 90° C. for 7 hours under a nitrogen environment; after the polymerization reaction is completed, a microsphere intermediate product is obtained by filtration using a Buchner funnel.

[0071] S6: First, wash the microsphere intermediate repeatedly with deionized water and / or ethanol for multiple times to remove the receiving solution remaining on the surface of the microsphere intermediate; then place the microsphere intermediate under vacuum conditions of 0.08Mpa~0.1Mpa and 40℃~70℃ for vacuum drying for 6~12h (the optimal process conditions are vacuum degree 0.1Mpa, drying temperature 65℃, and drying time 8h); polystyrene-divinylbenzene microspheres with a spherical shape, an average particle size of 281.53μm, and uniform particle size (CV value of 4.6%) can be obtained.

[0072] Embodiment 4:

[0073] This embodiment 4 also provides a method for preparing large-size monodisperse polystyrene-divinylbenzene microspheres, which mainly includes the following steps:

[0074] S1: providing styrene, divinylbenzene (used as a cross-linking agent) and an oil-soluble initiator, wherein the styrene and the divinylbenzene are both of analytical grade, and the oil-soluble initiator is dimethyl azobisisobutyrate AIBME.

[0075] By weight percentage, 70 weight percent of styrene, 28 weight percent of divinylbenzene and 2 weight percent of dimethyl azobisisobutyrate (AIBME) were uniformly mixed to prepare a dispersed phase fluid.

[0076] Note: In the preparation of the dispersed phase fluid in this embodiment 4, the weight ratio of the styrene to the divinylbenzene is preferably controlled to be 2.5:1. Similar to the above embodiment 1, this embodiment 4 can also effectively enhance the strength, pressure resistance / pressure bearing performance, ball yield, etc. of the microsphere primary product by adding the above preferred amount of divinylbenzene.

[0077] S2: providing a surfactant, wherein the surfactant is composed of polyethylene glycol PEG, polyvinyl pyrrolidone PVP and polyether F127 in a weight ratio of 1:1:2.

[0078] By weight percentage, 8 weight percent of the surfactant and 92 weight percent of deionized water are uniformly mixed to prepare a continuous phase fluid.

[0079] Note: Similar to the above-mentioned embodiment 1, this embodiment 4 also does not impose any restrictions on the specific processing order of the dispersed phase fluid and the continuous phase fluid.

[0080] S3: Provide a microfluidic chip. The structure / type of the microfluidic chip used in this embodiment 4 is the same as the microfluidic chip used in the above embodiment 1, so it will not be described here.

[0081] The dispersed phase fluid prepared in S1 is introduced into the inner phase microchannel of the microfluidic chip, and the continuous phase fluid prepared in S2 is introduced into the outer phase microchannel of the microfluidic chip; and the flow ratio of the dispersed phase fluid to the continuous phase fluid is controlled to be 1:1.58 (approximately), specifically: the flow rate of the dispersed phase fluid is 60 μL / min, and the flow rate of the continuous phase fluid is 95 μL / min; by utilizing the shearing operation of the fluid, a primary microsphere with large production capacity and uniform particle size is obtained.

[0082] S4: First, the microspheres are placed in a receiving solution to obtain a ball-liquid mixture; wherein the receiving solution can preferably be a polyethylene glycol (PEG) aqueous solution with a mass percentage concentration of 8% to further activate the surface of the microspheres and reduce the surface tension; then, the weight percentage of the receiving solution relative to the ball-liquid mixture is adjusted (i.e., a certain amount of the receiving solution is added) so that the volume fraction of the microspheres in the ball-liquid mixture is 5% to 15% (preferably about 10%); to ensure that the microspheres are intact and uniform in size, and to ensure the quality of the following polymerization reaction.

[0083] Similar to the above-mentioned embodiment 1, the present embodiment 4 optimizes the volume fraction / volume ratio of the microsphere preliminary product in the ball-liquid mixture, so that the microsphere preliminary product can be well dispersed in the ball-liquid mixture, thereby avoiding adhesion between the microsphere preliminary products during the subsequent polymerization reaction, reducing the deformation and breakage of the microspheres, and improving the quality of the finished microspheres (the polystyrene-divinylbenzene microspheres).

[0084] S5: The prepared ball-liquid mixture is transferred to a reactor (a four-mouth reactor can be used), and a polymerization reaction is carried out at a reaction temperature of 50° C. for 18 hours under a nitrogen environment; after the polymerization reaction is completed, a microsphere intermediate product is obtained by filtration using a Buchner funnel.

[0085] S6: First, wash the microsphere intermediate repeatedly with deionized water and / or ethanol for multiple times to remove the receiving solution remaining on the surface of the microsphere intermediate; then place the microsphere intermediate under vacuum conditions of 0.08Mpa~0.1Mpa and 40℃~70℃ for vacuum drying for 6~12h (the optimal process conditions are vacuum degree 0.1Mpa, drying temperature 60℃, and drying time 8h); polystyrene-divinylbenzene microspheres with a spherical shape, an average particle size of 449.21μm, and uniform particle size (CV value of 4.8%) can be obtained.

[0086] 2. Performing performance tests on the polystyrene-divinylbenzene microspheres prepared in this application;

[0087] The polystyrene-divinylbenzene microspheres prepared in the present application were subjected to a number of performance tests, and the test methods and test results are shown below.

[0088] 1) Morphology analysis of the polystyrene-divinylbenzene microspheres;

[0089] The polystyrene-divinylbenzene microspheres prepared in Examples 1 to 4 of the present application were analyzed by scanning electron microscopy and optical microscopy. The analysis results are shown in the attached Figures 2 to 4 shown.

[0090] From the attached Figures 2 to 4 It can be seen that the polystyrene-divinylbenzene microspheres prepared in Examples 1 to 4 all present a spherical structure as a whole, and the average diameters of the polystyrene-divinylbenzene microspheres prepared in Examples 1 to 4 are 30.28 μm, 49.76 μm, 281.53 μm and 449.21 μm, respectively.

[0091] Description: Attached Figure 2 The numerical values ​​(such as 50 μm / 300 μm / 450 μm) represent the scale.

[0092] From the attached Figure 3 and 4 It can also be seen that the sizes of the polystyrene-divinylbenzene microspheres prepared in Examples 1 to 4 are highly monodisperse, and the CV values ​​are no more than 5% (4.9%, 4.5%, 4.6% and 4.8%, respectively), that is, the particle size of the polystyrene-divinylbenzene microspheres is uniform.

[0093] 2) Performance analysis of the polystyrene-divinylbenzene microspheres;

[0094] The pressure resistance value and the maximum flow rate at a pressure of 1 MPa of the polystyrene-divinylbenzene microspheres prepared in Examples 1 to 4 of the present application were tested using a chromatographic packing column (7.7*100 mm, column volume 5 mL). The test results are shown in Table 1 below.

[0095] Table 1 Performance test results of polystyrene-divinylbenzene microspheres prepared in Examples 1 to 4 of the present application

[0096] Test samples Withstand pressure(Mpa) Flow rate (cm / h) Example 1 ＞3.0 719 Example 2 ＞3.0 1061 Example 3 ＞3.0 6033 Example 4 ＞3.0 9168

[0097] It can be seen from Table 1 that the polystyrene-divinylbenzene microspheres prepared in Examples 1 to 4 of the present application all have good pressure resistance, and the maximum pressure resistance is greater than 3 MPa; and the obtained polystyrene-divinylbenzene microspheres all have a good flow rate under a pressure of 1 MPa, and the two-phase performance is improved relative to that of a single polystyrene-divinylbenzene microsphere.

[0098] The reason why the polystyrene-divinylbenzene microspheres prepared by the present invention can achieve the above advantages is that the present invention optimizes and innovates the preparation method and raw material formula of polystyrene-divinylbenzene microspheres, which is specifically manifested in: the present invention preferably adopts a preparation method combining microfluidic technology, polymerization reaction technology, vacuum drying technology, etc. to prepare the polystyrene-divinylbenzene microspheres, wherein 1) when the present invention uses microfluidic technology to prepare the primary microspheres, on the one hand, the raw material formula of the dispersed phase fluid is optimized to achieve the advantages of high strength, pressure resistance / strong pressure bearing performance, etc., so as to ensure that the primary microspheres are not easily damaged in the subsequent process, thereby ensuring that the finished microspheres (i.e., the polystyrene-divinylbenzene microspheres) have good spherical shape and high quality; on the other hand, the dispersed phase fluid and the 1) The flow rate ratio of the continuous phase fluid is optimally controlled, which can achieve a large production capacity of the microsphere preliminary product and controllable particle size, and can also better ensure that the shear force and surface tension between the dispersed phase fluid and the continuous phase fluid reach an optimal equilibrium state, so that a microsphere preliminary product with very high particle size uniformity can be obtained; 2) After the microsphere preliminary product is produced, the present invention adopts "first adjusting the volume fraction / volume ratio occupied by the microsphere preliminary product in the ball-liquid mixture to an optimal control value, and then subjecting the microsphere preliminary product to a polymerization reaction", which can effectively avoid deformation and breakage of the microspheres, further ensure that the spherical shape of the microsphere finished product is intact and the size is uniform, and also improve the quality of the polymerization reaction, thereby improving the quality of the microsphere finished product; 3) The present invention adopts vacuum drying technology to obtain the final microsphere finished product, which can further ensure that the size of the microsphere finished product is not deformed.

[0099] In addition to the above innovations, the present invention also makes the following improvements: The present invention optimizes the raw material formula of the continuous phase fluid, and in particular, the surfactant in the continuous phase fluid is composed of at least two surfactant components compounded in a preferred weight ratio, so that the continuous phase fluid can provide good shear force. And so on.

[0100] In summary, the present invention optimizes and innovates the preparation method and raw material formula of the polystyrene-divinylbenzene microspheres, and can obtain the polystyrene-divinylbenzene microspheres with adjustable particle size (such as large particle size, or even ultra-large particle size), good particle size uniformity (CV value is not greater than 5%), high strength, good pressure resistance, large production capacity, and wide application field; thus, the market demand is well met.

[0101] Many specific details are described in the above description to facilitate a full understanding of the present invention. However, the above description is only a preferred embodiment of the present invention. The present invention can be implemented in many other ways different from those described herein, so the present invention is not limited to the specific implementation disclosed above. At the same time, any person familiar with the art can make many possible changes and modifications to the technical solution of the present invention using the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing large-size monodisperse polystyrene-divinylbenzene microspheres, characterized in that: include: The formulated amounts of styrene, divinylbenzene and an oil-soluble initiator are uniformly mixed to prepare a dispersed phase fluid; wherein the weight ratio of the styrene to the divinylbenzene is (1.5-3):1; A surfactant is provided and dissolved in deionized water to prepare a continuous phase fluid; Providing a microfluidic chip, respectively passing the dispersed phase fluid and the continuous phase fluid into the two-phase microchannel of the microfluidic chip, and controlling the flow ratio of the dispersed phase fluid to the continuous phase fluid to be 1:(1.2-3.5) to obtain a primary microsphere product; The microspheres are placed in a receiving solution to obtain a ball-liquid mixture; and the volume fraction of the microspheres in the ball-liquid mixture is adjusted to be 5% to 15%; The prepared ball-liquid mixture is transferred into a reactor, and a polymerization reaction is carried out at a reaction temperature of 40° C. to 90° C. for 6 to 20 hours under a nitrogen environment; after the polymerization reaction is completed, the microsphere intermediate is obtained by suction filtration; The microsphere intermediate product is sequentially washed and vacuum dried to obtain polystyrene-divinylbenzene microspheres with a particle size of 20 to 500 μm and uniform particle size.

2. The method for preparing large-diameter monodisperse polystyrene-divinylbenzene microspheres according to claim 1, characterized in that: Calculated by weight percentage, the dispersed phase fluid has the following raw material formula: 55% to 72% styrene, 25% to 40% divinylbenzene and 0.1% to 10% oil-soluble initiator; wherein the weight ratio of the styrene to the divinylbenzene is (1.5 to 2.5):

1.

3. The method for preparing large-diameter monodisperse polystyrene-divinylbenzene microspheres according to claim 2, characterized in that: The oil-soluble initiator is selected from any one of tert-butyl peroxy-2-ethylhexanoate, azobisisoheptanenitrile and dimethyl azobisisobutyrate.

4. The method for preparing large-diameter monodisperse polystyrene-divinylbenzene microspheres according to claim 1, characterized in that: The flow ratio of the dispersed phase fluid to the continuous phase fluid is 1:(1.5-3).

5. The method for preparing large-diameter monodisperse polystyrene-divinylbenzene microspheres according to claim 4, characterized in that: The flow rates of the dispersed phase fluid and the continuous phase fluid are both no greater than 100 μL / min.

6. The method for preparing large-diameter monodisperse polystyrene-divinylbenzene microspheres according to claim 1, characterized in that: In terms of weight percentage, the continuous phase fluid is composed of a mixture of 3% to 8% of a surfactant and the remainder of deionized water; wherein the surfactant is selected from at least two of polyvinyl pyrrolidone, sodium dodecyl sulfate, polyethylene glycol, sodium dodecyl sulfate and polyether F127.

7. The method for preparing large-diameter monodisperse polystyrene-divinylbenzene microspheres according to claim 6, characterized in that: The surfactant is composed of polyvinyl pyrrolidone and sodium dodecyl sulfate in a weight ratio of 3:2; or, the surfactant is composed of polyethylene glycol and sodium dodecyl sulfate in a weight ratio of 5:1; or, the surfactant is composed of polyethylene glycol, polyvinyl pyrrolidone and sodium dodecyl sulfate in a weight ratio of 1:1:1; or, the surfactant is composed of polyethylene glycol, polyvinyl pyrrolidone and polyether F127 in a weight ratio of 1:1:

1.

8. The method for preparing large-diameter monodisperse polystyrene-divinylbenzene microspheres according to claim 1, characterized in that: The receiving solution is a surfactant aqueous solution with a mass percentage concentration of 0.5% to 10%, wherein the solute in the surfactant aqueous solution is selected from any one of polyvinyl pyrrolidone, sodium dodecyl sulfonate, sodium dodecyl sulfate, polyethylene glycol and polyether F127.

9. The method for preparing large-diameter monodisperse polystyrene-divinylbenzene microspheres according to claim 1, characterized in that: The processing parameters of the vacuum drying treatment are: vacuum degree of 0.08Mpa to 0.1Mpa, drying temperature of 40°C to 70°C, and drying time of 6 to 12h.

10. A large-size monodisperse polystyrene-divinylbenzene microsphere, characterized in that: The microspheres are prepared by the method for preparing large-size monodisperse polystyrene-divinylbenzene microspheres as described in any one of claims 1 to 9.

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