Radiation-resistant polystyrene resin preparation and aperture control method

Abstract

The invention discloses a method for preparing radiation-resistant polystyrene resin and controlling the aperture of the radiation-resistant polystyrene resin. The preparation method of the radiation-resistant polystyrene resin comprises the following steps: fully dissolving polyvinyl alcohol in deionized water, adding an organic phase containing styrene and the like into the deionized water, uniformly stirring and mixing, heating and carrying out a synthetic reaction to prepare non-porous matrix microspheres, and carrying out pore-forming and surface modification treatment on the matrix microspheres. Compared with the prior art, rapid preparation of the radiation-resistant porous mass transfer resin is achieved through two steps, the high grafting rate is kept through accurate control over a cross-linked skeleton, meanwhile, radiation resistance is considered, and the method has the advantages that the process is simple, the cost is low, the particle size is controllable and narrow in distribution, relevant parameters are easy to standardize, and the method is suitable for industrial amplification.

Description

Technical Field

[0001] This invention relates to a method for preparing a porous cation exchange resin, and more specifically to a method for preparing and controlling the pore size of a radiation-resistant polystyrene resin. Background Technology

[0002] Polystyrene-based porous resins are a class of functional polymer materials with a polystyrene backbone and controllable pore structure. Their unique physicochemical properties (such as high specific surface area, tunable pore size distribution, good mechanical strength, and surface modifiability) make them valuable in separation science, drug delivery, catalytic support, environmental remediation, and biomedicine. In chromatographic separation, porous microspheres, as stationary phases in high-performance liquid chromatography and solid-phase extraction, can significantly improve separation selectivity and column efficiency through precise control of their pore size and surface chemistry. In the nuclear industry, their porous structure allows for high loading and controlled release of functional groups, while their high specific surface area provides ideal adsorption sites for target substances, and their rigid framework ensures radiation stability. As an aromatic polymer, the benzene ring structure of polystyrene can effectively disperse radiation energy through a conjugated system, reducing the risk of main chain breakage. Introducing crosslinking agents (such as divinylbenzene) can significantly enhance its radiation resistance, as the crosslinked network can inhibit radiation-induced chain migration and degradation.

[0003] In recent years, with the development of nanotechnology and surface modification technology, the functionalization of polystyrene microspheres' pores (such as hydrophilic / hydrophobic modification and ion exchange group grafting) has further broadened their application scenarios. Through extensive research and in-depth analysis, the applicant found that existing preparation technologies still suffer from insufficient pore size uniformity and poor radiation stability, necessitating breakthroughs in performance through innovation in polymerization methodologies and mechanistic studies. Therefore, developing novel polystyrene-based radiation-resistant porous microsphere preparation technologies is not only of significant scientific importance but will also provide crucial material support for national strategic needs in energy, medicine, environmental protection, and other fields. Summary of the Invention

[0004] This invention provides a method for preparing radiation-resistant polystyrene resin and controlling its pore size that overcomes the shortcomings of existing technologies.

[0005] The method for preparing radiation-resistant polystyrene resin and controlling its pore size according to the present invention adopts suspension polymerization. The specific steps are as follows: polyvinyl alcohol is fully dissolved in deionized water, and then an organic phase containing styrene, divinylbenzene, and benzoyl peroxide is added. After stirring and mixing evenly, the mixture is heated to synthesize and react, and non-porous matrix microspheres are prepared. The matrix microspheres are then subjected to pore-forming and surface modification treatment: dichloromethane, a pore-forming agent, is added to the matrix microspheres. After swelling by heating, concentrated sulfuric acid is slowly added dropwise to carry out a sulfonation reaction. After sulfonation is completed, the solid is filtered out, and a diluted sulfuric acid solution is added to it. After the acidity inside the microspheres is balanced, the mixture is washed with ethanol and deionized water until the effluent is neutral. After filtration and drying, a radiation-resistant sulfonic acid-based porous cation exchange resin is obtained.

[0006] Preferably, the method for preparing the porous cation exchange resin of the present invention is as follows: 1) Preparation and mixing of aqueous and organic phases: a. Aqueous phase preparation: Add 0.8-1.5 g of polyvinyl alcohol to 80-100 ml of deionized water, and mechanically stir at 80-90℃ and 200-300 rpm until completely dissolved. Cool to room temperature for later use. b. Organic phase preparation: Benzoyl peroxide needs to be washed with anhydrous ethanol, then 40-50g of styrene, 3-5g of divinylbenzene and 0.3-0.4g of benzoyl peroxide are fully dissolved, and then dried for later use; c. Transfer the organic phase to the aqueous phase, stir thoroughly at 200-300 rpm to ensure uniform mixing, adjust the stirring speed to 500-600 rpm, emulsify for half an hour, and then proceed with the reaction described later. 2) Preparation of matrix microspheres: a. Heat the well-mixed organic and aqueous phases to 80-90℃, adjust the stirring speed to 600-700 rpm, and react for 5-8 hours.

[0007] b. After the reaction is complete, filter out the solid microspheres, wash the microspheres thoroughly with water until the filtrate is clear, then wash with ethanol, and then dry at 60-70℃ overnight to prepare non-porous matrix microspheres; 3) Hole formation and surface modification: a. Take a certain amount of microspheres (3-5g), add 8-12 ml of pore-forming agent dichloromethane, and allow them to fully swell for 1 hour at 60-70℃ and 100-150 rpm. Slowly add 40-60 ml of concentrated sulfuric acid, then raise the temperature to 85-90℃ and continue the reaction for 4-6 hours. b. After sulfonation, filter out the product and add 1.0-2.0 mol / L sulfuric acid. During this process, place the container containing the product in cooling water to ensure that its temperature is below 35°C. After standing for 1 hour to allow the internal acidity to reach equilibrium, wash with ethanol and deionized water respectively until neutral. After drying, obtain a porous cation exchange resin with sulfonic acid groups.

[0008] This invention provides a rapid and simple method for preparing porous cation exchange resin microspheres. The method overcomes the shortcomings of traditional synthesis processes, such as complex steps, uneven pore size, poor framework rigidity, and low grafting density. The microspheres prepared by this invention have a relatively uniform pore size of 100-200 nm and can be effectively scaled up in a reactor, enabling the mass production of radiation-resistant porous mass transfer resins. Compared with existing technologies, the advantages of this invention are: 1) Compared with the prior art, the present invention achieves rapid preparation of radiation-resistant porous mass transfer resin in two steps. The precise control of the crosslinking skeleton ensures that the high grafting rate is maintained while taking into account the radiation resistance.

[0009] 2) The suspension polymerization method used in this invention is simple, low-cost, has controllable particle size and narrow distribution, and the relevant parameters are easy to standardize, making it suitable for industrial scale-up. Attached Figure Description

[0010] Figure 1 This is a flowchart illustrating the preparation process of the present invention.

[0011] Figure 2 The images show the morphology of the matrix microspheres and the porous cation exchange resin.

[0012] Figure 3 This is a particle size distribution diagram of porous cation exchange resin.

[0013] Figure 4 This shows the elemental distribution of the porous cation exchange resin.

[0014] Figure 5 These are morphological images of porous cation exchange resins after irradiation with different doses.

[0015] Figure 6 Radiation resistance test of porous cation exchange resin. Detailed Implementation

[0016] The present invention will now be described in detail with reference to the embodiments and accompanying drawings.

[0017] The preparation process of the porous cation exchange resin of the present invention is as follows: Figure 1 As shown, the specific preparation process is as follows: 1) Preparation and mixing process of aqueous and organic phases: a. Aqueous phase preparation: Add 2,2% polyvinyl alcohol and 200ml deionized water to a 1L three-necked flask, and mechanically stir at 85°C and 270 rpm until dissolved. After complete dissolution, cool to room temperature for later use.

[0018] b. Organic phase preparation: Weigh 95 g of styrene, 8 g of divinylbenzene, and 0.8 g of benzoyl peroxide, and dissolve them completely.

[0019] c. Mixing the aqueous and organic phases: Transfer the organic phase to the aqueous phase. After the transfer is complete, stir at 270 rpm for half an hour to ensure uniform mixing. Then adjust the speed to 600 rpm and emulsify for half an hour before starting the next reaction.

[0020] 2) Preparation process of matrix microspheres: a. Adjust the stirring speed to 600 rpm, raise the temperature to 85 ℃, and react for 6 h.

[0021] b. After the reaction is complete, filter the reaction solution, wash the microspheres repeatedly with water until the filtrate is clear, then wash three times with ethanol, and dry in an oven at 60°C overnight to prepare non-porous matrix microspheres with a particle size distribution of 40-60 micrometers.

[0022] 3) Hole formation and surface modification process: a. Take 10g of dried microspheres, add 20 ml of pore-forming agent dichloromethane, and allow them to fully swell at 60℃ and 100 rpm for 1 hour. Slowly add 80 ml of concentrated sulfuric acid, then raise the temperature to 85℃ and continue the reaction for 5 hours. b. After sulfonation, filter out the product, place it in a beaker, add 1.0 mol / L sulfuric acid, and cool the beaker with cooling water during the process to ensure the temperature is below 35℃. After standing for 1 hour to allow the internal acidity to reach equilibrium, wash with ethanol and deionized water respectively until neutral, and dry in an oven to obtain a porous cation exchange resin with sulfonic acid groups and a pore size of 150 nm.

[0023] 4) Product testing process: a. The surface morphology of matrix microspheres and porous microspheres was observed using scanning electron microscopy, such as... Figure 2 As shown, the surface pore size is approximately 150 nm; b. Particle size distribution of porous microspheres as follows Figure 3 As shown, the particles are mainly distributed in the range of 40-60 micrometers, with relatively uniform particle size. Elemental analysis results are as follows: Figure 4 As shown, the sulfur content reached 15.08%, indicating that the sulfonic acid groups were effectively grafted onto the porous microspheres, giving the microspheres good adsorption performance. c. The radiation resistance of the microspheres was evaluated by gamma irradiation. The morphology of the microspheres after irradiation with 100 KGy, 200 KGy, and 400 KGy, and the control group before irradiation, are shown below. Figure 5 As shown, the surface remains smooth and intact, without cracks, and the adsorption performance is as expected. Figure 6 As shown, the adsorption capacity did not decrease, and the adsorption performance remained stable, indicating that the microspheres have good radiation resistance.

[0024] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. The parts of the present invention not described in detail are well known to those skilled in the art. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing radiation-resistant polystyrene resin and controlling its pore size, comprising suspension polymerization, characterized in that: Polyvinyl alcohol was fully dissolved in deionized water, and then an organic phase containing styrene, divinylbenzene, and benzoyl peroxide was added. After stirring and mixing evenly, the mixture was heated to synthesize the reaction and prepare non-porous matrix microspheres. The matrix microspheres were then subjected to pore-forming and surface modification treatment: dichloromethane, a pore-forming agent, was added to the matrix microspheres. After swelling by heating, concentrated sulfuric acid was slowly added dropwise to carry out a sulfonation reaction. After sulfonation was completed, the solid was filtered out, and a diluted sulfuric acid solution was added to it. After the acidity inside the microspheres was balanced, the mixture was washed with ethanol and deionized water until the effluent was neutral. After filtration and drying, a radiation-resistant sulfonic acid-based porous cation exchange resin was obtained.

2. The method for preparing the porous cation exchange resin according to claim 1, characterized in that: 1) Preparation and mixing of aqueous and organic phases: a. Aqueous phase preparation: Add 0.8-1.5 g of polyvinyl alcohol to 80-100 ml of deionized water, and mechanically stir at 80-90℃ and 200-300 rpm until completely dissolved. Cool to room temperature for later use. b. Organic phase preparation: Benzoyl peroxide needs to be washed with anhydrous ethanol, then 40-50g of styrene, 3-5g of divinylbenzene and 0.3-0.4g of benzoyl peroxide are fully dissolved, and then dried for later use; c. Transfer the organic phase to the aqueous phase, stir thoroughly at 200-300 rpm to ensure uniform mixing, adjust the stirring speed to 500-600 rpm, emulsify for half an hour, and then proceed with the reaction described later. 2) Preparation of matrix microspheres: a. Heat the well-mixed organic and aqueous phases to 80-90℃, adjust the stirring speed to 600-700 rpm, and react for 5-8 hours; b. After the reaction is complete, filter out the solid microspheres, wash the microspheres thoroughly with water until the filtrate is clear, then wash with ethanol, and then dry at 60-70℃ overnight to prepare non-porous matrix microspheres; 3) Hole formation and surface modification: a. Take a certain amount of microspheres (3-5g), add 8-12 ml of pore-forming agent dichloromethane, and allow them to fully swell for 1 hour at 60-70℃ and 100-150 rpm. Slowly add 40-60 ml of concentrated sulfuric acid, then raise the temperature to 85-90℃ and continue the reaction for 4-6 hours. b. After sulfonation, filter out the product and add 1.0-2.0 mol / L sulfuric acid. During this process, place the container containing the product in cooling water to ensure that its temperature is below 35°C. After standing for 1 hour to allow the internal acidity to reach equilibrium, wash with ethanol and deionized water respectively until neutral. After drying, obtain a porous cation exchange resin with sulfonic acid groups.

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