Preparation method for preparing monodisperse polystyrene microspheres through photo-initiation rapid polymerization

Abstract

The invention belongs to the technical field of high polymer material synthesis, and provides a preparation method for preparing monodisperse polystyrene microspheres through photo-initiation rapid polymerization. The polystyrene microspheres prepared through the processes of porous seed microsphere preparation, monomer absorption, photo-initiation rapid polymerization and the like have the advantages of being uniform and adjustable in particle size, simple and efficient in preparation method, beneficial to mass production and the like, and can be applied to large-scale preparation of monodisperse polystyrene microspheres.

Description

Technical Field

[0001] This invention belongs to the field of polymer material synthesis technology, and relates to a method for preparing monodisperse polystyrene microspheres by photoinitiated rapid polymerization. Background Technology

[0002] Microspheres are spherical particles made from inorganic or polymeric composite materials, with particle sizes ranging from nanometers to micrometers. Their unique structure endows them with numerous superior properties, such as flowability, biocompatibility, surface effects, and volume effects. Furthermore, by functionalizing and compounding molecules and materials with different structures and properties onto the surface or interior of microspheres, or by designing various pore sizes, hollow structures, core-shell structures, and other functionalities, microspheres have found wide applications in cutting-edge technologies, national defense, and various sectors of the national economy, including catalysis, chromatography, optical devices, microelectronic devices, biomedicine, and energy storage. Polystyrene matrix, due to its inherent phenyl hydrophobic functional groups, can be directly used as a reversed-phase chromatography packing material. Its greatest advantage is its strong chemical stability, heat resistance, and acid and alkali resistance, and it can operate within a wide pH range of 1-14. Therefore, polystyrene microsphere chromatographic packing materials are among the materials with the longest service life and best dirt resistance of all chromatographic packing materials / media currently available. In addition, polystyrene microspheres are also widely used in liquid crystal displays, microelectronic packaging, and optical devices due to their adjustable mechanical properties, elasticity, and certain light transmittance.

[0003] However, the large-scale preparation of monodisperse polymer microspheres has always been a challenge in the field of microsphere applications. The currently common method is seed polymerization, which first uses dispersion polymerization / emulsion polymerization to prepare monodisperse small-diameter microspheres, and then uses these as seed microspheres for swelling and growth to obtain larger-diameter microspheres. Seed polymerization generally employs heated polymerization, and each preparation of a specific microsphere size requires a lengthy process of feeding, swelling, and heated polymerization. Furthermore, the feeding rate, swelling rate, and reaction rate are difficult to match and control, resulting in a long time consumption and a high risk of failure for large-scale preparation of monodisperse microspheres using seed polymerization.

[0004] Therefore, optimizing and improving seed polymerization technology to achieve efficient, simple, and large-scale preparation of monodisperse microspheres is a requirement for the development and application of microspheres. Summary of the Invention

[0005] To meet the development and application needs for efficient, simple, and large-scale preparation of monodisperse polystyrene microspheres, this invention provides a method for preparing monodisperse polystyrene microspheres through photo-initiated rapid polymerization. Using styrene as the monomer, divinylbenzene as the crosslinking agent, and porous polystyrene microspheres as seeds, the method involves the preparation of porous seed microspheres, monomer absorption, and photo-initiated rapid polymerization. This method offers advantages such as uniform microsphere size, adjustable particle size, simple and efficient preparation, and suitability for mass production. It can be applied to the large-scale preparation of solid / porous monodisperse polystyrene microspheres.

[0006] The technical solution adopted by this invention to solve its technical problem is as follows:

[0007] This invention provides a method for preparing polystyrene porous microsphere seeds. The method involves adding a stabilizer, a monomer containing an initiator, a crosslinking agent, and a pore-forming agent to a dispersion medium, and then preparing polystyrene seeds with uniform particle size by stirring, dispersing, and heating.

[0008] Furthermore, a water / ethanol solution was used as the dispersion medium.

[0009] Furthermore, styrene is used as the monomer, divinylbenzene as the crosslinking agent, and toluene or xylene organic solvent as the porogen.

[0010] Furthermore, the polymerization temperature is 65-85℃, and the reaction time is 16-24h.

[0011] Furthermore, cellulose ether, hydroxypropyl cellulose, or polyvinylpyrrolidone are used as stabilizers, and azobisisobutylene or benzoyl peroxide are used as initiators.

[0012] Another aspect of the present invention provides a method for preparing monodisperse polystyrene microspheres by rapid polymerization using a photoinitiator. The method involves absorbing monomers through porous seed microspheres and then rapidly polymerizing them using photoinitiation to obtain monodisperse polystyrene microspheres.

[0013] Furthermore, the monomer absorption temperature is 40-60℃, and the absorption time is 0.5-1h.

[0014] Furthermore, ultraviolet photoinitiators such as alkyl phenyl ketones and organic peroxides are used.

[0015] Furthermore, the photoinitiated polymerization time is 0.5-3 hours.

[0016] Furthermore, by adding toluene / xylene or not adding toluene / xylene during the monomer absorption process of porous seed microspheres, monodisperse polystyrene porous microspheres can be obtained. Using these monodisperse porous seed microspheres, and then sequentially performing monomer absorption and photo-initiated rapid polymerization, polystyrene microspheres with larger particle sizes can be obtained.

[0017] The beneficial effects of this invention are as follows:

[0018] The preparation method of the present invention has the advantages of uniform microsphere size, adjustable particle size, simple and efficient preparation method, and is conducive to mass production. It can be applied to the large-scale preparation of monodisperse polystyrene solid / porous microspheres. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the preparation process of monodisperse polystyrene microspheres using photoinitiated rapid polymerization according to the present invention.

[0020] Figure 2 This is a scanning electron microscope image of monodisperse polystyrene microspheres. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] A method for preparing monodisperse polystyrene microspheres by photoinitiated rapid polymerization, the specific steps of which are:

[0023] Step 1: Preparation of porous seed microspheres: Add stabilizer, styrene containing initiator, divinylbenzene, and toluene / xylene to an aqueous / ethanol solution, and stir to disperse. Heat to the polymerization temperature of 65-85℃. After polymerization, cool, and then undergo filtration, washing, and drying to obtain monodisperse porous seed microspheres.

[0024] Step 2, Monomer Absorption: Porous seed microspheres, emulsifier / stabilizer, styrene containing photoinitiator, and divinylbenzene are sequentially added to an water / ethanol solution and stirred to disperse. The mixture is then heated to the monomer absorption temperature of 40-60℃ and absorbed for 0.5-1 hour.

[0025] Step 3, photo-initiated rapid polymerization: After the system stabilizes, irradiate it with ultraviolet light to rapidly initiate polymerization for 0.5-3 hours. After polymerization is complete, cool the system and then proceed with filtration, washing, and drying to obtain polystyrene microspheres.

[0026] The unique feature of this invention is that toluene / xylene is added during step 2 of monomer absorption, followed by step 3 of photoinitiated rapid polymerization, to prepare monodisperse, large-particle-size porous polystyrene microspheres. Using these microspheres as seeds, repeating steps 2 and 3 of monomer absorption and photoinitiated rapid polymerization allows for the preparation of polystyrene microspheres with even larger particle sizes.

[0027] Example 1

[0028] 250 mL of 70% ethanol aqueous solution was added to a three-necked flask, and nitrogen / argon gas was introduced. 1 g of azobisisobutyronitrile (AIBN) initiator was dissolved in 100 g of styrene and added to the flask. Then, 0.2 g of divinylbenzene, 3 g of xylene, and 20 g of polyvinylpyrrolidone were added. After stirring and dispersing for 30 min, the mixture was heated to 80 °C and reacted for 18 h. The mixture was then cooled, filtered, washed, and dried to obtain polystyrene porous microsphere seeds with an average particle size of 2.5 μm.

[0029] 4 g of photoinitiator was dissolved in 400 g of styrene, and then added sequentially to a three-necked flask containing 1000 mL of 70% ethanol aqueous solution, along with 30 g of polystyrene porous microsphere seeds (average particle size 2.5 μm), 0.8 g of divinylbenzene, and 80 g of polyvinylpyrrolidone. Nitrogen / argon gas was introduced, and the mixture was stirred and heated to 60 °C for absorption for 0.5 h. The heating was then turned off, and the mixture was irradiated with ultraviolet light for 2 h. After filtration, washing, and drying, polystyrene microspheres with an average particle size of 7.5 μm were obtained.

[0030] Example 2

[0031] 250 mL of 70% ethanol aqueous solution was added to a three-necked flask, and nitrogen / argon gas was introduced. 0.8 g of azobisisobutyronitrile (AIB) initiator was dissolved in 100 g of styrene and added to the flask. Then, 0.3 g of divinylbenzene, 3 g of xylene, and 25 g of polyvinylpyrrolidone were added. After stirring and dispersing for 30 min, the mixture was heated to 75 °C and reacted for 24 h. The mixture was then cooled, filtered, washed, and dried to obtain polystyrene porous microsphere seeds with an average particle size of 1.8 μm.

[0032] 4 g of photoinitiator was dissolved in 400 g of styrene, and then added sequentially to a three-necked flask containing 1000 mL of 70% ethanol aqueous solution, along with 30 g of polystyrene porous microsphere seeds (average particle size 1.8 μm), 0.8 g of divinylbenzene, and 80 g of polyvinylpyrrolidone. Nitrogen / argon gas was introduced, and the mixture was stirred and heated to 55 °C for 1 h for absorption. The heating was then turned off, and the reaction was irradiated with ultraviolet light for 2.5 h. After filtration, washing, and drying, polystyrene microspheres with an average particle size of 5.6 μm were obtained.

[0033] Example 3

[0034] 300 mL of 70% ethanol aqueous solution was added to a three-necked flask, and nitrogen / argon gas was introduced. 1 g of azobisisobutyronitrile (AIBN) initiator was dissolved in 100 g of styrene and added to the flask. Then, 0.25 g of divinylbenzene, 3 g of xylene, and 30 g of polyvinylpyrrolidone were added. After stirring and dispersing for 30 min, the mixture was heated to 75 °C and reacted for 24 h. The mixture was then cooled, filtered, washed, and dried to obtain polystyrene porous microsphere seeds with an average particle size of 1.3 μm.

[0035] 4 g of photoinitiator was dissolved in 400 g of styrene, and then added sequentially to a three-necked flask containing 1000 mL of 70% ethanol aqueous solution, along with 30 g of polystyrene porous microsphere seeds (average particle size 1.3 μm), 0.8 g of divinylbenzene, 12 g of xylene, and 80 g of polyvinylpyrrolidone. Nitrogen / argon gas was introduced, and the mixture was stirred and heated to 60 °C for absorption for 0.5 h. The heating was then turned off, and the reaction was irradiated with ultraviolet light for 2.5 h. After filtration, washing, and drying, polystyrene porous microspheres with an average particle size of 4.0 μm were obtained.

[0036] 4g of photoinitiator was dissolved in 400g of styrene, and then added sequentially to a three-necked flask containing 1000mL of 70% ethanol aqueous solution, along with 30g of porous polystyrene microspheres with an average particle size of 4.0μm, 0.8g of divinylbenzene, and 80g of polyvinylpyrrolidone. Nitrogen / argon gas was introduced, and the mixture was stirred and heated to 60℃ for absorption for 0.5h. Heating was then turned off, and the reaction was carried out under ultraviolet light irradiation for 2.5h. The mixture was filtered, washed, and dried to obtain polystyrene microspheres with an average particle size of 12.0μm. Figure 2 ).

[0037] Example 4

[0038] 300 mL of 70% ethanol aqueous solution was added to a three-necked flask, and nitrogen / argon gas was introduced. 1 g of azobisisobutyronitrile (AIBN) initiator was dissolved in 100 g of styrene and added to the flask. Then, 0.25 g of divinylbenzene, 3 g of xylene, and 30 g of polyvinylpyrrolidone were added. After stirring and dispersing for 30 min, the mixture was heated to 75 °C and reacted for 24 h. The mixture was then cooled, filtered, washed, and dried to obtain polystyrene porous microsphere seeds with an average particle size of 1.3 μm.

[0039] 4 g of photoinitiator was dissolved in 400 g of styrene, and then added sequentially to a three-necked flask containing 1000 mL of 70% ethanol aqueous solution, along with 30 g of polystyrene porous microsphere seeds (average particle size 1.3 μm), 0.8 g of divinylbenzene, and 80 g of polyvinylpyrrolidone. Nitrogen / argon gas was introduced, and the mixture was stirred and heated to 60 °C for absorption for 0.5 h. The heating was then turned off, and the reaction was irradiated with ultraviolet light for 2.5 h. After filtration, washing, and drying, polystyrene microspheres with an average particle size of 3.8 μm were obtained.

[0040] 4 g of photoinitiator was dissolved in 300 g of styrene, and then added sequentially to a three-necked flask containing 1000 mL of 70% ethanol aqueous solution, along with 30 g of porous polystyrene microspheres with an average particle size of 3.8 μm, 0.8 g of divinylbenzene, and 80 g of polyvinylpyrrolidone. Nitrogen / argon gas was introduced, and the mixture was stirred and heated to 60 °C for absorption for 0.5 h. Heating was then turned off, and the reaction was carried out under ultraviolet light for 2.5 h. The mixture was filtered, washed, and dried to obtain polystyrene microspheres with an average particle size of 8.2 μm. It is worth noting that since the microspheres obtained from the first seed polymerization are not porous, the amount of styrene monomer added during the second seed polymerization should not be excessive; otherwise, exo-seed polymerization will occur, forming smaller microspheres.

[0041] Table 1. Preparation process and results of each embodiment

[0042]

[0043] .

Claims

1. A method for preparing polystyrene porous microsphere seeds, characterized in that: Stabilizers, monomers containing initiators, crosslinking agents, and pore-forming agents are added to a dispersion medium, and polystyrene seeds with uniform particle size are prepared by stirring, dispersing, and heating to polymerize.

2. The method for preparing polystyrene porous microsphere seeds according to claim 1, characterized in that: A water / ethanol solution was used as the dispersion medium.

3. The method for preparing polystyrene porous microsphere seeds according to claim 1, characterized in that: Styrene is used as the monomer, divinylbenzene as the crosslinking agent, and toluene or xylene organic solvent as the porogen.

4. The method for preparing polystyrene porous microsphere seeds according to claim 1, characterized in that: The polymerization temperature is 65-85℃, and the reaction time is 16-24h.

5. The method for preparing polystyrene porous microsphere seeds according to claim 1, characterized in that: Cellulose ether, hydroxypropyl cellulose or polyvinylpyrrolidone are used as stabilizers, and azobisisobutylene or benzoyl peroxide are used as initiators.

6. A method for preparing monodisperse polystyrene microspheres by rapid polymerization using a photoinitiator, characterized in that: Monodisperse polystyrene microspheres are obtained by rapidly polymerizing porous seed microspheres after they absorb monomers using photoinitiation.

7. The preparation method according to claim 6, characterized in that: The monomer absorption temperature is 40-60℃, and the absorption time is 0.5-1h.

8. The preparation method according to claim 6, characterized in that: Ultraviolet photoinitiators such as alkyl phenyl ketones and organic peroxides are used.

9. The preparation method according to claim 6, characterized in that: Photoinitiated polymerization time is 0.5-3 hours.

10. The preparation method according to any one of claims 7-8, characterized in that: By adding or not adding toluene / xylene during the monomer absorption process of porous seed microspheres, monodisperse polystyrene microspheres can be obtained; and these monodisperse porous seed microspheres can then be subjected to monomer absorption and photo-initiated rapid polymerization in sequence to obtain polystyrene microspheres with larger particle sizes.

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