Preparation method of monodisperse polymer chromatographic filler

Abstract

The invention discloses a preparation method of a monodisperse polymer chromatographic filler, which comprises the following steps: synthesizing seed microspheres with uniform particle size by a dispersion polymerization method, and preparing porous microspheres with required size and aperture by a two-step seed swelling method. In the preparation process, the selection, the mixing mode, the reaction temperature, the reaction time, the material proportion and the like of all the raw materials are accurately controlled, for example, the mass ratio of the dispersing agent to the vinyl monomer is (5-20)%: 1, and the like. A particle size control and pore size distribution model is also introduced to assist in controlling the product performance. The preparation method is simple in process, controllable in process and easy for industrial large-scale production. The obtained monodisperse polymer chromatographic filler has the advantages of accurately adjustable particle size and pore size, good monodispersity, good sphericity and narrow pore size distribution, can be widely applied to the fields of biochemistry, catalytic carriers, drug carriers and the like, effectively overcomes the defects of the traditional chromatographic filler, and meets the requirements of the market on high-performance chromatographic filler.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a method for preparing a monodisperse polymer chromatographic filler. Background Art

[0002] In the field of polymer materials and chromatographic separation, chromatographic fillers play a vital role. With the development of related technologies, the performance requirements for chromatographic fillers are also increasing. Traditional carbohydrate microspheres and silica gel fillers once dominated the market, but they each have obvious defects. Although carbohydrate microspheres have a high load capacity and are easy to modify, their size uniformity is poor and their pressure resistance is poor, which greatly limits their scope of application. Although silica gel fillers are low-cost, easy to modify and resistant to high pressure, they have poor chemical stability and have obvious limitations when facing the analysis of alkaline compounds. Therefore, the development of polymer chromatographic fillers with better performance has become an urgent need for the development of the industry.

[0003] Currently, there are various methods for preparing polymer microspheres, each with its own advantages and disadvantages. Emulsion polymerization produces relatively small polymer microspheres. While suspension polymerization can produce larger microspheres, the particle size distribution is wide, requiring screening for use, increasing application cost and difficulty. Dispersion polymerization can synthesize monodisperse 1-10 μm microspheres of uniform size, but residual surfactants and stabilizers remain after the reaction, affecting the purity of the polymer and potentially hindering its application in areas requiring high purity. The emerging SPG membrane emulsification method offers unique advantages in preparing micron-sized monodisperse polymer microspheres and can precisely control particle size, but its technology is difficult to master and the equipment is expensive, making it unsuitable for large-scale industrial production. While the seed swelling method can synthesize 5-20 μm monodisperse uniform microspheres and can produce microspheres of various structures, precise control of particle size and pore size remains to be improved.

[0004] Against this backdrop, developing a method for preparing monodisperse polymer chromatographic fillers with a simple preparation method, a controllable reaction process, and ease of industrial production, while effectively addressing the issues of poor monodispersity and uneven pore size distribution of polymer microspheres, has become a pressing task. Such a method would not only overcome the shortcomings of existing preparation technologies but also meet growing market demand and promote further development in related fields. Summary of the Invention

[0005] In order to overcome the shortcomings and deficiencies of the prior art, the present invention provides a method for preparing a monodisperse polymer chromatographic filler.

[0006] The technical solution adopted by the present invention is a method for preparing a monodisperse polymer chromatographic filler, which comprises:

[0007] S1: Select the raw materials required for the dispersion polymerization process, mix the specified dispersant and reaction solvent in a certain proportion, and use ultrasound to promote uniform dispersion of the two. The ultrasound frequency is set between 350-370 Hz and the ultrasound duration is controlled to 30 minutes to form a stable dispersion system; a specific vinyl monomer and a specific initiator are mixed in proportion, and an electric stirring method is used to control the stirring speed within the range of 110-130 rpm and the stirring time is 30 minutes to ensure that the two are fully mixed;

[0008] S2: The uniformly mixed reaction system in S1 is placed in a reaction device and heated under constant temperature conditions. The reaction temperature is precisely controlled at 70°C and the reaction duration is set to 24 hours. During this process, the vinyl monomer undergoes polymerization under the action of the initiator to generate seed microspheres with uniform particle size;

[0009] S3: After the reaction in S2 is completed, the product containing the seed microspheres is removed from the reaction device and thoroughly washed with water and alcohol to remove residual impurities in the product; after washing, the impurities are further separated by positive pressure filtration to obtain preliminary purification of the seed microspheres; the purified seed microspheres are dried and stored;

[0010] S4: Performing a seed swelling activation step, selecting a predetermined swelling agent, mixing the seed microspheres stored in S3 with the swelling agent at a certain mass ratio, and using ultrasonic emulsification with an ultrasonic power controlled at 1800-2200W at a temperature of 25-40°C for 12-24 hours to activate the surface and internal structure of the seed microspheres;

[0011] S5: After activation is completed, a swelling step is performed, wherein the second monomer, crosslinker, porogen, initiator, and SDS solution are prepared in a specific ratio to form an emulsified mixture as a swelling monomer; the seed microspheres activated in S4 are mixed with the swelling monomer and ultrasonic emulsification is used again. The ultrasonic power is also controlled at 1800-2200W, and the temperature is 25-40°C. The swelling is continued for 12-24 hours to allow the seed microspheres to further absorb the swelling monomer and expand in volume;

[0012] S6: After the swelling is completed, the temperature of the reaction system is increased to initiate the polymerization reaction of the system. The polymerization temperature is controlled at 65-80°C, and the polymerization reaction duration is set to 12-36 hours. After the reaction is completed, the product is treated with a porogen extractor, and then filtered, washed, and dried to obtain monodisperse polymer microspheres. After further treatment, the desired monodisperse polymer chromatographic filler is obtained.

[0013] Furthermore, the reaction solvent is one or a combination of n-butanol solution, ethanol solution, and isopropanol solution. When multiple solvents are mixed, the volume ratio of alcohol to water in the solvent must meet the range of 90-100:0-10; the dispersant is one of polyvinyl pyrrolidone, hydroxypropyl cellulose, polyethylene glycol, and polyvinyl alcohol; the initiator is one of potassium persulfate, ammonium persulfate, dibenzoyl peroxide, and azobisisobutyronitrile; and the monomer having a vinyl group is styrene.

[0014] Furthermore, the mass ratio of the dispersant to the vinyl monomer needs to be controlled within the range of 5%-20%:1; the mass ratio of the initiator to the vinyl monomer should be in the range of 1%-4%:1; and the amount of the vinyl monomer used accounts for 10-30% of the total weight of the reaction system.

[0015] Furthermore, in the S4 activation step, the seeds are non-crosslinked polystyrene microspheres, and the swelling agent is one or a combination of dibutyl phthalate (DBP), chloroform, and toluene; the mass ratio of the swelling agent to the seeds is set in the range of 10-100:1.

[0016] Furthermore, in the S5 swelling step, the second monomer is one or more combinations of methyl methacrylate (MMA), styrene (St), glycidyl methacrylate (GMA), and hydroxyethyl methacrylate (HEMA); the cross-linking agent is divinylbenzene (DVB) or ethylene glycol dimethacrylate (EGDMA); the porogen is one or more combinations of toluene, cyclohexanol, n-heptane, dodecanol, and linear polystyrene; the initiator is dibenzoyl peroxide (BPO) or azobisisobutyronitrile (AIBN); and the mass ratio of the second monomer to the seed is 2-20:1.

[0017] Furthermore, in the S5 swelling step, the mass ratio of the crosslinking agent to the vinyl monomer is 0.1-5:1; the mass ratio of the porogen to the vinyl monomer is 0.5-2:1; and the mass ratio of the initiator to the vinyl monomer is 5%-30%:1.

[0018] Furthermore, a particle size control model is introduced: Wherein, D is the particle size of the final prepared monodisperse polymer chromatographic filler, D0 is the initial particle size of the seed microspheres, m sw is the mass of the swelling agent, m s is the mass of the seed microspheres, m cm is the total mass of the cross-linking agent and the porogen, m vmis the mass of the vinyl monomer, k1 and k2 are the particle size control coefficients, k1 ranges from 0.01 to 0.05, and k2 ranges from 0.005 to 0.02. The model is constructed based on the influence of the mass of the swelling agent, cross-linking agent, porogen and vinyl monomer on the final filler particle size during the preparation process.

[0019] Furthermore, a pore size distribution model is constructed: Where P(d) represents the probability distribution function of pore size d, μ is the average pore size, σ is the standard deviation of pore size distribution, and m is the probability distribution function of pore size d. ca is the mass of the porogen, m vm is the mass of vinyl monomer, m cm is the mass of the cross-linking agent, is a function related to the mass ratio of porogen and crosslinker, ∫(x, y) = 1 + 0.5x - 0.2y. This model comprehensively considers the mass ratio of porogen and crosslinker to vinyl monomer and is used to describe the pore size distribution of monodisperse polymer chromatographic packing.

[0020] Furthermore, in the S1 mixing process, when multiple reaction solvents are used, the solvent mixing uniformity is measured by the mixing uniformity coefficient M. Among them, V i is the volume of the i-th solvent, C i is the concentration of the i-th solvent, n is the number of solvent types, and the mixing uniformity coefficient M must meet the range of 0.95-1.05.

[0021] Furthermore, during the S6 polymerization reaction, the polymerization rate is calculated by the reaction rate model R p =k p ×[M]×[I] 0.5 Monitor and control, where R p is the polymerization reaction rate, k p is the polymerization reaction rate constant, [M] is the monomer concentration, and [I] is the initiator concentration. In the present preparation method, the polymerization reaction rate is maintained within the range of 0.01-0.05 mol / (L·s) by monitoring the monomer concentration and the initiator concentration in real time and adjusting the reaction conditions according to the model.

[0022] Beneficial Effects: The present invention proposes a method for preparing monodisperse polymer chromatographic fillers. This method synthesizes seed microspheres through a specific dispersion polymerization process. The dispersant and reaction solvent are first ultrasonically mixed, and then the vinyl monomer and initiator are electrically stirred and mixed. The reaction is carried out under precisely controlled temperature and time, ensuring the uniformity of the seed microsphere particle size. The subsequent two-step seed swelling method strictly controls the conditions of each activation, swelling, and initiation polymerization step, such as the selection of swelling agent and swelling monomer, and parameters such as reaction temperature and time. The monodisperse polymer chromatographic filler prepared exhibits excellent particle size and pore size control. The introduced particle size control model and pore size distribution model are constructed based on the influence of the mass ratio of each raw material on particle size and pore size, making the preparation process more scientific and precise, and the particle size and pore size distribution characteristics of the filler can be flexibly adjusted according to actual needs. For example, by adjusting the mass ratio of the swelling agent, cross-linking agent, porogen, and vinyl monomer, the particle size and pore size can be effectively controlled. During the reaction process, the mixing uniformity coefficient is used to monitor the mixing effect of the reaction solvent to ensure a stable reaction environment. The polymerization reaction rate model is used to monitor and control the polymerization reaction rate to ensure smooth reaction progress. The monodisperse polymer chromatographic filler finally prepared has the characteristics of good monodispersity, good sphericity and narrow pore size distribution. It can be widely used in many fields such as protein separation, biomedicine, standard measurement, chemical catalysis, etc., providing a high-quality material foundation for the development of related industries. This method effectively solves many problems existing in traditional chromatographic fillers, such as poor size uniformity and pressure resistance of carbohydrate microspheres, and poor chemical stability and acid and alkali resistance of silica gel fillers. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a flow chart of the overall steps of the present invention. DETAILED DESCRIPTION

[0024] It should be noted that, unless there is a conflict, the embodiments and features in the embodiments of this application can be combined with each other. The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] like Figure 1 As shown, a method for preparing a monodisperse polymer chromatographic filler comprises the following steps:

[0026] S1: Select the raw materials required for the dispersion polymerization process, mix the set dispersant and reaction solvent in a certain proportion, and use ultrasound to promote uniform dispersion of the two. The ultrasonic frequency is set between 350-370 Hz and the ultrasonic duration is controlled to 30 minutes to form a stable dispersion system; then, a specific monomer with a vinyl group and a specific initiator are mixed in proportion, and an electric stirring method is used to control the stirring speed within the range of 110-130 rpm and the stirring time is 30 minutes to ensure that the two are fully mixed.

[0027] Specifically, in the S1 step of the preparation of monodisperse polymer chromatographic fillers, the raw materials must first be selected and pretreated. The mixing of the dispersant and the reaction solvent is the key starting link of this step. Taking polyvinyl pyrrolidone as a dispersant and ethanol as a reaction solvent as an example, the two are mixed in a certain proportion and then treated by ultrasound. The ultrasonic frequency is set at 350-370Hz, and the ultrasonic duration is 30min. This parameter setting is of great significance. At this frequency and duration, the high-frequency vibration generated by ultrasound can break the original aggregation state between the dispersant and solvent molecules, so that the dispersant is evenly dispersed in the solvent to form a stable dispersed system. This is like in a cup of mixed liquid, through stirring at a specific frequency and time, the substances that were originally easy to clump are evenly distributed in the liquid, ensuring the uniformity of subsequent reactions.

[0028] Next, the vinyl monomer is mixed with the initiator. Styrene is used as the vinyl monomer and azobisisobutyronitrile is used as the initiator. Electric stirring is adopted, the stirring speed is controlled at 110-130rpm, and the stirring time is 30min. Such stirring conditions can allow the monomer and the initiator to fully contact, so that the initiator is evenly dispersed in the monomer. The stirring process is like mixing two sands of different colors thoroughly so that each part of them can be evenly distributed together. In this process, the uniform mixing of the monomer and the initiator is the basis for the smooth progress of the subsequent polymerization reaction. If the mixing is uneven, the polymerization reaction may occur locally, resulting in microspheres with uneven particle size.

[0029] This series of operations creates favorable conditions for the subsequent polymerization reaction. A stable dispersion system ensures that each seed microsphere experiences a similar environment during its formation, facilitating the formation of uniformly sized seed microspheres. Thorough mixing of the monomer and initiator ensures uniform polymerization initiation throughout the system, avoiding inconsistent reactions and guaranteeing the quality and performance of the seed microspheres.

[0030] S2: The uniformly mixed reaction system in S1 is placed in a reaction device and heated under constant temperature conditions. The reaction temperature is precisely controlled at 70°C and the reaction duration is set to 24 hours. During this process, the vinyl monomer undergoes polymerization reaction under the action of the initiator to generate seed microspheres with uniform particle size.

[0031] Specifically, step S2 is to carry out a polymerization reaction to generate seed microspheres based on the reaction system formed in S1. The reaction system is placed in a reaction device, and the reaction temperature is strictly controlled to be 70°C and the reaction time is 24 hours. The reaction temperature of 70°C is an appropriate temperature verified by a large number of experiments. At this temperature, the initiator can decompose at an appropriate rate to produce free radicals, and the free radicals initiate the polymerization reaction of the vinyl monomer. If the temperature is too high, the initiator decomposes too quickly, and the reaction rate is difficult to control, which may cause the polymerization reaction to be too intense and the particle size distribution of the generated microspheres to become wider; if the temperature is too low, the initiator decomposes slowly, the polymerization reaction proceeds too slowly, and may even fail to react completely, affecting the formation of seed microspheres.

[0032] The 24-hour reaction time is also crucial to ensuring the polymerization reaction proceeds fully. During this time, the vinyl monomers, under the action of free radicals generated by the initiator, continuously undergo polymerization, gradually forming seed microspheres of a certain particle size. Taking the preparation of polystyrene seed microspheres as an example, during this process, styrene monomer molecules are linked together by chemical bonds, forming increasingly larger polymer chains, which ultimately aggregate into microspheres. As the reaction time progresses, the particle size of the microspheres gradually increases, and by the 24-hour reaction time, the microspheres have essentially reached the desired uniform size.

[0033] The seed microspheres generated in this step serve as the foundation for the subsequent preparation of monodisperse polymer chromatographic fillers. The uniformity of their particle size directly impacts the quality of the final product. A uniform seed microsphere size ensures consistent growth and change during the subsequent swelling and polymerization processes, resulting in a highly monodisperse polymer chromatographic filler. However, if the seed microspheres are not uniform in size, the subsequent chromatographic filler will exhibit performance variations, impacting its effectiveness in practical applications.

[0034] S3: After the reaction in S2 is completed, the product containing the seed microspheres is removed from the reaction device and thoroughly washed with water and alcohol to remove residual impurities in the product; after washing, the impurities are further separated by positive pressure filtration to obtain preliminary purification of the seed microspheres; finally, the purified seed microspheres are dried and properly stored.

[0035] Specifically, step S3 mainly involves post-processing the product obtained after the reaction in step S2. The product often contains unreacted raw materials, by-products produced during the reaction, and other impurities. These impurities can affect the purity and performance of the seed microspheres, and therefore require cleaning and purification. The product is thoroughly cleaned with water and alcohol, for example, by alternating cleaning with deionized water and anhydrous ethanol. Water can dissolve some water-soluble impurities, and alcohol can dissolve some organic impurities. By alternately cleaning multiple times, most impurities can be effectively removed.

[0036] After cleaning, positive pressure filtration is used to further separate impurities. Positive pressure filtration utilizes a pressure differential to force liquid through a filter medium, trapping impurities. Choosing a filter medium with the appropriate pore size is crucial in this process. Generally, a filter medium that effectively traps impurities while minimizing the loss of seed microspheres is chosen. Positive pressure filtration further removes any remaining impurities after cleaning, improving the purity of the seed microspheres.

[0037] Finally, the purified seed microspheres are dried and properly stored. Drying removes residual moisture and solvent from the surface and interior of the seed microspheres, preventing them from deteriorating or agglomerating during storage. Proper storage protects the seed microspheres from external environmental influences, such as dust and moisture. For example, the dried seed microspheres can be stored in a dry, sealed container in a cool, well-ventilated area. This series of post-processing operations results in higher purity and better stability of the seed microspheres, providing high-quality raw materials for subsequent swelling and polymerization reactions.

[0038] S4: Perform the activation step of seed swelling. Select the set swelling agent, mix the seed microspheres stored in S3 with the swelling agent in a certain mass ratio, use ultrasonic emulsification, control the ultrasonic power at 1800-2200W, and continue to act for 12-24 hours at a temperature of 25-40°C to activate the surface and internal structure of the seed microspheres and prepare for subsequent swelling.

[0039] Specifically, step S4 is the activation link of seed swelling. Selecting a suitable swelling agent is the key. Taking dibutyl phthalate as an example, it is mixed with non-cross-linked polystyrene seed microspheres in a mass ratio of 10-100:1. The role of the swelling agent is to make the surface and internal structure of the seed microspheres loose, thereby increasing their absorption capacity for subsequent swelling monomers. During the mixing process, ultrasonic emulsification is adopted, and the ultrasonic power is controlled at 1800-2200W. Ultrasonic emulsification can make the swelling agent more evenly dispersed around the seed microspheres, and can promote the swelling agent to penetrate into the interior of the seed microspheres faster, thereby accelerating the activation process.

[0040] The activation temperature is controlled between 25-40°C and the activation time is 12-24 hours. This temperature and time range ensures the effective action of the swelling agent on the seed microspheres while preventing structural damage from excessive temperatures or prolonged activation. Within this temperature range, the swelling agent molecules are sufficiently active to interact with the molecular chains of the seed microspheres, loosening their structure. Over time, the swelling agent gradually penetrates the microspheres, causing them to expand in volume and increasing the number of pores on the surface and within them.

[0041] This activation step alters the physical and chemical properties of the seed microspheres, creating favorable conditions for the subsequent swelling process. The activated seed microspheres are able to more fully absorb the swelling monomer, thereby forming more uniform and high-performance polymer microspheres during the subsequent swelling and polymerization reactions, ultimately producing high-quality monodisperse polymer chromatographic fillers. However, if the activation process is inadequate, the seed microspheres' ability to absorb the swelling monomer may be insufficient, resulting in an uneven pore size distribution in the final product, compromising its effectiveness in applications such as chromatographic separations.

[0042] S5: After activation is completed, a swelling step is performed, in which the second monomer, cross-linking agent, porogen, initiator and SDS solution are prepared into an emulsified mixture in a specific proportion as a swelling monomer; the seed microspheres activated in S4 are mixed with the swelling monomer, and ultrasonic emulsification is used again. The ultrasonic power is also controlled at 1800-2200W, and the swelling is continued for 12-24 hours at a temperature of 25-40°C, so that the seed microspheres further absorb the swelling monomer and achieve volume expansion.

[0043] Specifically, step S5 involves further swelling the seed microspheres activated in step S4. First, a swelling monomer must be prepared. The swelling monomer is an emulsified mixture of a second monomer, a crosslinker, a porogen, an initiator, and an SDS solution in specific proportions. For example, using methyl methacrylate as the second monomer, divinylbenzene as the crosslinker, toluene as the porogen, and dibenzoyl peroxide as the initiator, these substances are mixed in proportion and then ultrasonically emulsified using an ultrasonic power controllable between 1800 and 2200 W for a period of time to form a uniform emulsified system.

[0044] The activated seed microspheres are then mixed with the swelling monomer and allowed to swell continuously for 12-24 hours at a temperature of 25-40°C. During this process, the activated seed microspheres absorb the swelling monomer, further expanding their volume. During absorption, the second monomer participates in the polymerization reaction of the microspheres, increasing the polymer content of the microspheres. The crosslinker forms a cross-linked structure within the microspheres, enhancing their mechanical strength and stability. The presence of the porogen creates pores within the microspheres, which are crucial for the separation performance of the chromatographic packing. The initiator provides the initiation conditions for the subsequent polymerization reaction.

[0045] The swelling process is like "feeding" the already loose seed microspheres with various nutrients, enabling them to continue growing and developing. By precisely controlling the ratio of the various components in the swelling monomer, as well as the swelling temperature and duration, the degree of microsphere swelling and the resulting structure can be effectively controlled. For example, increasing the proportion of crosslinker will increase the degree of crosslinking and enhance mechanical strength, but may also reduce the microspheres' flexibility. Adjusting the amount of porogen can alter the pore size and distribution within the microspheres. This step is crucial for preparing monodisperse polymer chromatographic fillers with specific pore sizes and properties, directly impacting the quality and application of the final product.

[0046] S6: After the swelling is completed, the temperature of the reaction system is increased to initiate the polymerization reaction of the system. The polymerization temperature is controlled at 65-80°C, and the polymerization reaction duration is set to 12-36 hours. After the reaction is completed, the product is treated with a porogen extractor, and then filtered, washed, and dried to finally obtain monodisperse polymer microspheres, which are further treated to obtain the desired monodisperse polymer chromatographic filler.

[0047] Specifically, step S6 initiates the polymerization reaction and post-processes the product to obtain the final monodisperse polymer chromatographic filler. After swelling is complete, the temperature of the reaction system is raised to 65-80°C to initiate polymerization, with the polymerization time controlled between 12 and 36 hours. Within this temperature range, the initiator begins to decompose, producing free radicals, which trigger polymerization reactions among the various components in the swollen monomer. As the polymerization reaction proceeds, the polymer molecular chains within the microspheres continue to grow and crosslink, gradually stabilizing the microsphere structure and enhancing its mechanical properties.

[0048] After the polymerization reaction is complete, the product needs to be treated with a porogen extractant. Using tetrahydrofuran as an extraction agent, for example, this extraction removes the porogen from the microspheres, thereby forming a porous structure within the microspheres. These pores are key to the efficient separation of monodisperse polymer chromatographic packings. After extraction, the product requires post-processing, including filtration, washing, and drying. Filtration removes large impurities that may have been produced during the reaction; washing further removes residual extraction agent, unreacted monomer, and other impurities; and drying removes moisture from the product, stabilizing it.

[0049] After this series of operations, the resulting monodisperse polymer chromatographic filler exhibits good monodispersity, excellent sphericity, and a narrow pore size distribution. For example, scanning electron microscopy revealed that the prepared microspheres exhibited uniform particle size, smooth surface, and a pore size distribution concentrated within a specific range. This high-quality chromatographic filler can be widely used in fields such as protein separation, biomedicine, standard metrology, and chemical catalysis, providing important material support for research and production in related fields. Throughout the preparation process, step S6 is the key link in transforming the initial preparations and reaction results into the final product, and plays a decisive role in the product's performance and quality.

[0050] Preferably, the reaction solvent is one or a combination of n-butanol solution, ethanol solution, and isopropanol solution. When multiple solvents are mixed, the volume ratio of alcohol to water in the solvent must meet the range of 90-100:0-10; the dispersant is one of polyvinyl pyrrolidone, hydroxypropyl cellulose, polyethylene glycol, and polyvinyl alcohol; the initiator is one of potassium persulfate, ammonium persulfate, dibenzoyl peroxide, and azobisisobutyronitrile; and the monomer having a vinyl group is styrene.

[0051] Specifically, the reaction solvent can be selected from one or more of n-butanol solution, ethanol solution, and isopropanol solution, and the volume ratio of alcohol to water in the solvent is 90-100:0-10. Taking ethanol solution as an example, when preparing seed microspheres, ethanol can provide a suitable dispersion environment for the reaction. Its specific ratio with water can ensure that the dispersant, monomer and initiator are evenly dispersed, promoting the uniform polymerization reaction. If the alcohol content is too high, it may cause the solubility of some substances to deteriorate; if the alcohol content is too low, the presence of water may affect the reaction activity. Dispersants such as polyvinyl pyrrolidone can be adsorbed on the surface of seed microspheres to prevent the microspheres from agglomerating during the reaction and ensure the monodispersity of the microspheres. Initiators such as azobisisobutyronitrile decompose at a specific temperature to produce free radicals, which initiate the polymerization of vinyl monomers. Styrene is used as the vinyl monomer because of its active chemical properties and can be effectively polymerized to form polymer microspheres under the action of the initiator.

[0052] Preferably, the mass ratio of the dispersant to the vinyl monomer needs to be controlled within the range of 5%-20%:1; the mass ratio of the initiator to the vinyl monomer should be within the range of 1%-4%:1; and the amount of the vinyl monomer used accounts for 10-30% of the total weight of the reaction system.

[0053] Specifically, the mass ratio of dispersant to vinyl monomer is 5%-20%:1. If the dispersant ratio is too low, the microspheres cannot be fully coated, which can easily lead to microsphere agglomeration. If the ratio is too high, excessive dispersant residue will affect product purity. For example, a mass ratio of dispersant to styrene of 10%:1 can effectively maintain the dispersion of the microspheres. The mass ratio of initiator to vinyl monomer is 1%-4%:1, which affects the polymerization reaction rate. If the ratio is too low, the reaction will be slow or even incomplete polymerization; if the ratio is too high, the reaction rate will be too fast and difficult to control, which can easily lead to a wide microsphere size distribution. The amount of vinyl monomer used accounts for 10-30% of the total weight of the reaction system. Too little will result in a small number of microspheres; too much will increase the viscosity of the system, making the reaction difficult to control and affecting the quality of the microspheres.

[0054] Preferably, in the S4 activation step, the seeds are non-crosslinked polystyrene microspheres, and the swelling agent is one or a combination of dibutyl phthalate (DBP), chloroform, and toluene; and the mass ratio of the swelling agent to the seeds is set in the range of 10-100:1.

[0055] Specifically, during the seed swelling activation step, the seed type is specified to be non-crosslinked polystyrene microspheres, and the swelling agent can be selected from one or a combination of dibutyl phthalate (DBP), chloroform, and toluene, with the swelling agent to seed mass ratio being 10-100:1. Taking dibutyl phthalate as an example, it can penetrate into the interior of the non-crosslinked polystyrene microspheres, causing the microspheres to swell, increasing the internal space of the microspheres and creating conditions for the entry of subsequent swelling monomers. The appropriate mass ratio is critical. If the swelling agent is too little, the activation effect is poor, and the microspheres will not absorb enough subsequent swelling monomers. If too much, the microspheres may overswell or even rupture. For example, when the swelling agent to seed mass ratio is 50:1, the seed microspheres can be effectively activated, facilitating subsequent reactions.

[0056] Preferably, in the S5 swelling step, the second monomer is one or more combinations of methyl methacrylate (MMA), styrene (St), glycidyl methacrylate (GMA), and hydroxyethyl methacrylate (HEMA); the cross-linking agent is divinylbenzene (DVB) or ethylene glycol dimethacrylate (EGDMA); the porogen is one or more combinations of toluene, cyclohexanol, n-heptane, dodecanol, and linear polystyrene; the initiator is dibenzoyl peroxide (BPO) or azobisisobutyronitrile (AIBN); and the mass ratio of the second monomer to the seed is 2-20:1.

[0057] Specifically, the optional types of the second monomer, cross-linking agent, porogen and initiator in the swelling step are clarified, as well as the mass ratio of the second monomer to the seed of 2-20:1. The second monomer, such as methyl methacrylate, can copolymerize with the polymer in the seed microspheres to change the chemical composition and properties of the microspheres. Cross-linking agents, such as divinylbenzene, form a cross-linked structure inside the microspheres, enhancing the mechanical strength and stability of the microspheres, making them less likely to deform during subsequent use. Porogen, such as toluene, is removed after the polymerization reaction, thereby forming pores inside the microspheres. These pores are the key to the separation function of chromatographic fillers. Initiators, such as dibenzoyl peroxide, initiate the polymerization reaction to solidify the microsphere structure. The mass ratio of the second monomer to the seed affects the final performance of the microspheres. If the ratio is too low, the performance of the microspheres will not change significantly; if the ratio is too high, it may cause excessive cross-linking of the microspheres, affecting their flexibility and pore size distribution.

[0058] Preferably, in the swelling step S5, the mass ratio of the crosslinking agent to the vinyl monomer is 0.1-5:1; the mass ratio of the porogen to the vinyl monomer is 0.5-2:1; and the mass ratio of the initiator to the vinyl monomer is 5%-30%:1.

[0059] Specifically, the mass ratios of the cross-linker, porogen, initiator, and vinyl monomer in the swelling step are defined. The mass ratio of the cross-linker to the vinyl monomer is 0.1-5:1, and this ratio determines the degree of cross-linking of the microspheres. If the degree of cross-linking is too low, the mechanical strength of the microspheres will be poor; if it is too high, the microspheres will be too hard and brittle. The mass ratio of the porogen to the vinyl monomer is 0.5-2:1, which controls the size and number of pores inside the microspheres. When the ratio is low, the pores are fewer and smaller; when the ratio is high, the pores increase and become larger, but this may affect the strength of the microspheres. The mass ratio of the initiator to the vinyl monomer is 5%-30%:1, which affects the speed and extent of the polymerization reaction. The appropriate ratio ensures that the reaction is sufficient and stable, and avoids adverse effects on the quality of the microspheres caused by too fast or too slow reactions.

[0060] Preferably, a particle size control model is introduced: Wherein, D is the particle size of the final prepared monodisperse polymer chromatographic filler, D0 is the initial particle size of the seed microspheres, m sw is the mass of the swelling agent, m s is the mass of the seed microspheres, m cm is the total mass of the cross-linking agent and the porogen, m vm is the mass of the vinyl monomer, k1 and k2 are particle size control coefficients, with k1 ranging from 0.01 to 0.05 and k2 from 0.005 to 0.02. This model is based on the influence of the mass of the swelling agent, crosslinking agent, porogen, and vinyl monomer on the final filler particle size during the preparation process. By adjusting the mass ratio of each material, the filler particle size can be effectively controlled according to this model.

[0061] Specifically, a particle size control model is introduced, the principle of which is based on the influence of the mass of materials such as swelling agents, cross-linking agents, porogens, and vinyl monomers on the final filler particle size. In actual preparation, the swelling agent causes the seed microspheres to swell and increase the particle size; the cross-linking agent and porogen participate in the reaction, affecting the internal structure and volume changes of the microspheres, and thus affecting the particle size. For example, when the amount of swelling agent increases, the microspheres absorb more swelling agent and the particle size increases; changes in the amount of cross-linking agent and porogen adjust the degree of cross-linking and pore structure inside the microspheres, indirectly affecting the particle size. By adjusting the mass ratio of these materials, the filler particle size can be effectively controlled according to this model, and monodisperse polymer chromatographic fillers with particle sizes that meet the requirements of different applications can be prepared.

[0062] Preferably, a pore size distribution model is constructed: Where P(d) represents the probability distribution function of pore size d, μ is the average pore size, σ is the standard deviation of pore size distribution, and m is the probability distribution function of pore size d. ca is the mass of the porogen, m vm is the mass of vinyl monomer, m cm is the mass of the cross-linking agent, I(x, y) = 1 + 0.5x - 0.2y, a function related to the mass ratio of the porogen and crosslinker. This model comprehensively considers the mass ratio of the porogen and crosslinker to the vinyl monomer and is used to describe the pore size distribution of monodisperse polymer chromatographic packings, facilitating precise control of the packing's pore size distribution characteristics.

[0063] Specifically, the pore size distribution of monodisperse polymer chromatographic packings is described by comprehensively considering the mass ratio of the porogen and crosslinker to the vinyl monomer. The porogen forms pores within the microspheres, and the crosslinker influences the crosslinking structure of the microspheres. Changes in the mass ratio of the two can alter the size, shape, and distribution of the pores. For example, increasing the amount of porogen may increase the number and size of pores; increasing the amount of crosslinker increases the degree of crosslinking of the microspheres, which may make the pore distribution more uniform or change the pore connectivity. Using this model, the ratios of these materials can be purposefully adjusted during the preparation process to precisely control the pore size distribution characteristics of the packing to meet the chromatographic packing pore size requirements of different separation tasks.

[0064] Preferably, in the S1 mixing process, when multiple reaction solvents are used, the solvent mixing uniformity is measured by the mixing uniformity coefficient M. Among them, V i is the volume of the i-th solvent, C i is the concentration of the i-th solvent, n is the number of solvent types, and the mixing uniformity coefficient M needs to meet the range of 0.95-1.05 to ensure that the reaction solvents are evenly mixed and provide a stable environment for subsequent reactions.

[0065] Specifically, the mixing uniformity coefficient is used to measure the mixing effect of multiple reaction solvents, and the mixing uniformity coefficient must meet the range of 0.95-1.05. When using multiple reaction solvents, such as ethanol and n-butanol, the properties of different solvents are different. If the mixing is uneven, it will lead to different local compositions of the reaction system, affecting the uniformity of the polymerization reaction. For example, in the process of dispersed polymerization, uneven solvent mixing may cause the monomer concentration in some areas to be too high or too low, resulting in inconsistent microsphere particle size. By monitoring the mixing uniformity coefficient, it is ensured that the solvents are fully mixed, providing a stable and uniform environment for subsequent reactions, and ensuring the quality and monodispersity of the seed microspheres.

[0066] Preferably, during the S6 polymerization reaction, the polymerization reaction rate is determined by the reaction rate model R p =k p ×[M]×[I] 0.5 Monitor and control, where R p is the polymerization reaction rate, k p is the polymerization reaction rate constant, [M] is the monomer concentration, and [I] is the initiator concentration. In the present preparation method, by real-time monitoring of the monomer concentration and the initiator concentration and adjusting the reaction conditions according to the model, the polymerization reaction rate is maintained in the range of 0.01-0.05 mol / (L·s), thereby ensuring smooth polymerization and obtaining a product with the expected performance.

[0067] Specifically, the polymerization reaction rate model is used to monitor and control the polymerization reaction rate to keep it within the range of 0.01-0.05 mol / (L·s). The polymerization reaction rate has a significant impact on product quality. If the reaction rate is too fast, it may lead to rapid accumulation of heat in the system, triggering violent polymerization, making the microsphere particle size distribution wider and the structure uneven; if the reaction rate is too slow, the production efficiency is low, and the reaction may be incomplete, affecting the performance of the microspheres. For example, when initiating the polymerization reaction, by real-time monitoring of the monomer concentration and initiator concentration, the reaction temperature, stirring speed and other conditions are adjusted according to the model to control the reaction rate within the appropriate range, ensure that the polymerization reaction proceeds smoothly, and obtain a monodisperse polymer chromatographic filler with stable performance and reliable quality.

[0068] A method for preparing monodisperse polymer chromatographic fillers has significant advantages and effectively overcomes many shortcomings of traditional chromatographic fillers and existing preparation technologies.

[0069] From a preparation perspective, this method utilizes a dispersion polymerization method to synthesize seed microspheres, followed by a two-step seed swelling method to produce the final product. The conditions for each step are clearly defined and controllable. For example, during dispersion polymerization, the dispersant and reaction solvent are ultrasonically mixed, and the vinyl monomer and initiator are electrically stirred. The reaction temperature and time are precisely set to 70°C and 24 hours, ensuring uniform particle size of the seed microspheres. Compared to traditional preparation methods, dispersion polymerization avoids the problems of small particle size in emulsion polymerization and wide particle size distribution requiring screening in suspension polymerization. It also addresses the drawback of residual surfactants affecting purity in dispersion polymerization. During the seed swelling stage, precise control of the temperature, time, and ratio of the various materials during the activation and swelling processes enables the microspheres to form the desired structure during the subsequent polymerization. This overcomes the drawback of existing technologies that have limited precise control of microsphere particle size and pore size. For example, the SPG membrane emulsification method, while capable of precise particle size control, suffers from complex technology and high equipment costs. This method offers a simpler preparation process and lowers costs.

[0070] In terms of product performance, the monodisperse polymer chromatographic filler obtained by this preparation method has obvious advantages. By introducing a particle size control model and a pore size distribution model, the particle size and pore size distribution characteristics of the filler can be flexibly adjusted according to actual needs. For example, the particle size of the microspheres can be precisely controlled within the required range, and the pore size distribution is narrow, which is unmatched by traditional carbohydrate microspheres and silica gel fillers. The carbohydrate microspheres have poor size uniformity and are not pressure-resistant, and the silica gel fillers have poor chemical stability and are not acid- and alkali-resistant. However, the polymer chromatographic filler has good monodispersity, good sphericity, and a narrow pore size distribution. It performs well in chemical stability and pressure resistance, and can be widely used in protein separation, biomedicine, standard measurement, chemical catalysis and other fields, greatly expanding its application range.

[0071] In terms of reaction process control, the mixing uniformity coefficient is used to monitor the mixing effect of the reaction solvent to ensure a stable reaction environment. The polymerization reaction rate model is used to monitor and control the polymerization reaction rate to ensure smooth reaction progress. This avoids product quality issues caused by unstable reaction conditions and overcomes the shortcomings of existing technologies that make the reaction process difficult to control. This makes the preparation process more scientific and efficient, and the product quality more stable and reliable, providing strong support for the development of related industries.

[0072] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various equivalent changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a monodisperse polymer chromatographic filler, characterized in that: The method includes: S1: Select the raw materials required for the dispersion polymerization process, mix the specified dispersant and reaction solvent in a certain proportion, and use ultrasound to promote uniform dispersion of the two. The ultrasound frequency is set between 350-370 Hz and the ultrasound duration is controlled to 30 minutes to form a stable dispersion system; a specific vinyl monomer and a specific initiator are mixed in proportion, and an electric stirring method is used to control the stirring speed within the range of 110-130 rpm and the stirring time is 30 minutes to ensure that the two are fully mixed; S2: The uniformly mixed reaction system in S1 is placed in a reaction device and heated under constant temperature conditions. The reaction temperature is precisely controlled at 70°C and the reaction duration is set to 24 hours. During this process, the vinyl monomer undergoes polymerization under the action of the initiator to generate seed microspheres with uniform particle size; S3: After the reaction in S2 is completed, the product containing the seed microspheres is removed from the reaction device and thoroughly washed with water and alcohol to remove residual impurities in the product; after washing, the impurities are further separated by positive pressure filtration to obtain preliminary purification of the seed microspheres; the purified seed microspheres are dried and stored; S4: Performing a seed swelling activation step, selecting a predetermined swelling agent, mixing the seed microspheres stored in S3 with the swelling agent at a certain mass ratio, and using ultrasonic emulsification with an ultrasonic power controlled at 1800-2200W at a temperature of 25-40°C for 12-24 hours to activate the surface and internal structure of the seed microspheres; S5: After activation is completed, a swelling step is performed, wherein the second monomer, crosslinker, porogen, initiator, and SDS solution are prepared in a specific ratio to form an emulsified mixture as a swelling monomer; the seed microspheres activated in S4 are mixed with the swelling monomer and ultrasonic emulsification is used again. The ultrasonic power is also controlled at 1800-2200W, and the temperature is 25-40°C. The swelling is continued for 12-24 hours to allow the seed microspheres to further absorb the swelling monomer and expand in volume; S6: After the swelling is completed, the temperature of the reaction system is increased to initiate the polymerization reaction of the system. The polymerization temperature is controlled at 65-80°C, and the polymerization reaction duration is set to 12-36 hours. After the reaction is completed, the product is treated with a porogen extractor, and then filtered, washed, and dried to obtain monodisperse polymer microspheres. After further treatment, the desired monodisperse polymer chromatographic filler is obtained.

2. The method for preparing a monodisperse polymer chromatographic filler according to claim 1, wherein: The reaction solvent is one or a combination of n-butanol solution, ethanol solution, and isopropanol solution. When multiple solvents are mixed, the volume ratio of alcohol to water in the solvent must meet the range of 90-100:0-10. The dispersant is one of polyvinyl pyrrolidone, hydroxypropyl cellulose, polyethylene glycol, and polyvinyl alcohol. The initiator is one of potassium persulfate, ammonium persulfate, dibenzoyl peroxide, and azobisisobutyronitrile. The monomer having a vinyl group is styrene.

3. The method for preparing a monodisperse polymer chromatographic filler according to claim 1, wherein: The mass ratio of the dispersant to the vinyl monomer needs to be controlled within the range of 5%-20%:1; the mass ratio of the initiator to the vinyl monomer should be in the range of 1%-4%:1; and the amount of the vinyl monomer used accounts for 10-30% of the total weight of the reaction system.

4. The method for preparing a monodisperse polymer chromatographic filler according to claim 1, wherein: In the S4 activation step, the seeds are non-crosslinked polystyrene microspheres, and the swelling agent is one or a combination of dibutyl phthalate (DBP), chloroform, and toluene; the mass ratio of the swelling agent to the seeds is set in the range of 10-100:

1.

5. The method for preparing a monodisperse polymer chromatographic filler according to claim 1, characterized in that: In the S5 swelling step, the second monomer is one or more combinations of methyl methacrylate (MMA), styrene (St), glycidyl methacrylate (GMA), and hydroxyethyl methacrylate (HEMA); the cross-linking agent is divinylbenzene (DVB) or ethylene glycol dimethacrylate (EGDMA); the porogen is one or more combinations of toluene, cyclohexanol, n-heptane, dodecanol, and linear polystyrene; the initiator is dibenzoyl peroxide (BPO) or azobisisobutyronitrile (AIBN); and the mass ratio of the second monomer to the seed is 2-20:

1.

6. The method for preparing a monodisperse polymer chromatographic filler according to claim 1, characterized in that: In the swelling step S5, the mass ratio of the crosslinking agent to the vinyl monomer is 0.1-5:1; the mass ratio of the porogen to the vinyl monomer is 0.5-2:1; and the mass ratio of the initiator to the vinyl monomer is 5%-30%:

1.

7. The method for preparing a monodisperse polymer chromatographic filler according to claim 1, characterized in that: Introducing the particle size control model: Wherein, D is the particle size of the final prepared monodisperse polymer chromatographic filler, D0 is the initial particle size of the seed microspheres, m sw is the mass of the swelling agent, m s is the mass of the seed microspheres, m cm is the total mass of the cross-linking agent and the porogen, m vm is the mass of the vinyl monomer, k1 and k2 are the particle size control coefficients, k1 ranges from 0.01 to 0.05, and k2 ranges from 0.005 to 0.

02. The model is constructed based on the influence of the mass of the swelling agent, cross-linking agent, porogen and vinyl monomer on the final filler particle size during the preparation process.

8. The method for preparing a monodisperse polymer chromatographic filler according to claim 1, wherein: Constructing a pore size distribution model: Where P(d) represents the probability distribution function of pore size d, μ is the average pore size, σ is the standard deviation of pore size distribution, and m is the probability distribution function of pore size d. ca is the mass of the porogen, m vm is the mass of vinyl monomer, m cm is the mass of the cross-linking agent, is a function related to the mass ratio of the porogen and cross-linker, f(x,y)=1+0.5x-0.2y. This model comprehensively considers the mass ratio of the porogen and cross-linker to the vinyl monomer and is used to describe the pore size distribution of monodisperse polymer chromatographic packings.

9. The method for preparing a monodisperse polymer chromatographic filler according to claim 1, characterized in that: In the S1 mixing process, when multiple reaction solvents are used, the solvent mixing uniformity is measured by the mixing uniformity coefficient M. Among them, V i is the volume of the i-th solvent, C i is the concentration of the i-th solvent, n is the number of solvent types, and the mixing uniformity coefficient M must meet the range of 0.95-1.

05.

10. The method for preparing a monodisperse polymer chromatographic filler according to claim 1, characterized in that: During the S6 polymerization reaction, the polymerization rate is calculated by the reaction rate model R p =k p ×[M]×[I] 0.5 Monitor and control, where R p is the polymerization reaction rate, k p is the polymerization reaction rate constant, [M] is the monomer concentration, and [I] is the initiator concentration. In the present preparation method, the polymerization reaction rate is maintained within the range of 0.01-0.05 mol / (L·s) by monitoring the monomer concentration and the initiator concentration in real time and adjusting the reaction conditions according to the model.

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