Controllable preparation method of carboxyl functionalized polystyrene latex microspheres

Abstract

The invention provides a controllable preparation method of carboxyl functionalized polystyrene latex microspheres, and belongs to the technical field of latex microsphere preparation. The carboxyl polystyrene latex microspheres (CPS) with various particle sizes of 100-400 nm, different carboxyl contents, monodispersity and uniform sphericity are prepared by adopting a soap-free emulsion polymerization method of adding a trace emulsifier and adding a functional comonomer through a one-step method or a two-step method, the particle sizes and the carboxyl density of the prepared carboxyl polystyrene latex microspheres are controllable, the surfaces are clean, the operation is simple, and the preparation method is suitable for industrial production. The method is simple in operation, good in repeatability and high in conversion rate, can meet the labeling requirements of most antigens and antibodies, and shows huge biomolecular analysis potential and application prospects in the field of biomedicine.

Description

Technical Field

[0001] The invention relates to the technical field of latex microsphere preparation, and in particular to a controllable preparation method of carboxyl functionalized polystyrene latex microspheres. Background Art

[0002] Polystyrene-based microspheres have many advantages, such as (1) large specific surface area; (2) easy preparation and good stability; (3) easy purification and separation; (4) good biocompatibility; (5) designability of molecular structure and function, and easy modification of some active groups on their surface, such as carboxyl, amino, thiol, etc.; (6) low price and high cost performance. They are highly favored in the fields of cell and molecular biology, immunology, targeted drug delivery, and physical dysfunction screening and diagnosis. Carboxyl-functionalized polystyrene latex microspheres can meet most antigen and antibody labeling needs, and the labeling process is stable and mature, and are widely used to measure the concentrations of various types of proteins in clinical samples.

[0003] At present, the preparation of nano-scale microspheres generally adopts emulsion polymerization. In emulsion polymerization, in order to stabilize the emulsion system, emulsifiers are usually added, which will have an adverse effect on the product when the microspheres are actually used. For example, in Chinese patent CN202211580039.6, a pure carboxyl polystyrene latex microsphere with controllable particle size and a preparation method thereof are disclosed. Although microspheres with uniform particle size can be prepared, the use of emulsifiers is easy to leave residues in the product, which may affect the purity and biocompatibility of the microspheres. Soap-free emulsion polymerization is a special emulsion polymerization technology. It does not use or only uses a very small amount (concentration less than the critical micelle concentration CMC) of emulsifiers during the polymerization process. If a controllable preparation method for effectively preparing carboxyl functionalized polystyrene latex microspheres can be designed based on soap-free emulsion polymerization, it will be of great significance to the development of polystyrene latex microsphere technology. Summary of the invention

[0004] In view of the defects of the prior art, the present invention provides a controllable preparation method of carboxyl functionalized polystyrene latex microspheres. The particle size and carboxyl density of the prepared carboxyl polystyrene latex microspheres are controllable, the operation is simple, the repeatability is good, the conversion rate is high, and most antigen and antibody labeling requirements can be met.

[0005] In order to achieve the above purpose, the present invention solves the technical problem by adopting the following technical solutions: In one aspect, the present invention provides a controllable preparation method of carboxyl functionalized polystyrene latex microspheres, the method adopting a one-step method or a two-step method, comprising the following steps: One-step preparation of CPS latex microspheres: a certain amount of H2O, NaHCO3, NaOH, a trace amount of emulsifier, styrene and functional monomers (acrylic acid or methacrylic acid) are added to a three-necked flask, and the mixture is stirred and mixed evenly after nitrogen deoxygenation. The mixture is heated to reflux at 70-90°C, and a certain volume of potassium persulfate solution with a concentration of 20-50 g / L is injected into the flask. The mixture is stirred and refluxed for 8-20 h, and the obtained white emulsion is stored in a wide-mouth plastic bottle at room temperature for later use.

[0006] CPS latex microspheres were prepared by a two-step method: a certain amount of H2O, NaHCO3, NaOH, a trace amount of emulsifier, and styrene were added to a three-necked flask, the mixture was stirred and mixed evenly after nitrogen deoxygenation, and the mixture was heated to reflux at 70-90 °C. A certain volume of potassium persulfate solution with a concentration of 20-50 g / L was injected into the flask, and after stirring and reflux reaction for 3-6 h, 5.0-30 g of functional monomer acrylic acid or methacrylic acid was injected and added. The stirring and reflux reaction was continued for 4-10 h. The obtained white emulsion was stored in a wide-mouth plastic bottle at room temperature for later use.

[0007] In some of the embodiments, the particle size is regulated by the dosage of sodium dodecylbenzene sulfonate and potassium persulfate and the pH value; the carboxyl content on the surface of the latex microspheres is controlled by changing the type (acrylic acid or methacrylic acid) and dosage of the carboxylating agent.

[0008] In some embodiments, the concentration of NaHCO3 is 0.02-0.06 g / L. The pH of the reaction system is regulated by using one or a mixture of NaHCO3 or NaOH.

[0009] In some embodiments, the trace emulsifier is sodium dodecylbenzene sulfonate with a concentration lower than the critical micelle concentration; the concentration of the sodium dodecylbenzene sulfonate is 0-0.03wt%.

[0010] In some of the embodiments, the styrene concentration is 10-20wt%; the surface of the microspheres is carboxyl functionalized with one or a mixture of acrylic acid or methacrylic acid, and the mass ratio of styrene to the functional monomer acrylic acid or methacrylic acid is (15-5):1.

[0011] In some embodiments, the potassium persulfate is added in an amount of 0.5 wt% to 3 wt% of styrene, the reaction temperature is 70 to 90° C., and the stirring speed is 200 to 400 rpm.

[0012] In some of the embodiments, the one-step preparation method refers to a method in which the functional monomers acrylic acid or methacrylic acid are uniformly stirred with styrene and then added to the reaction system for reaction, and the reaction time is 8 to 20 hours.

[0013] In some of the embodiments, the two-step preparation method refers to first preparing polystyrene seeds by soap-free emulsion polymerization, and then adding functional monomers acrylic acid or methacrylic acid to the system containing seed microspheres to continue the polymerization reaction for 4 to 10 hours.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The invention prepares a carboxyl functionalized polystyrene latex microsphere by a one-step method or a two-step method, and the particle size can be regulated by optimizing the dosage of sodium dodecylbenzene sulfonate and potassium persulfate and pH, and the surface carboxyl content of the latex microsphere is controlled by changing the type and dosage of the carboxylating agent, so that CPS latex microspheres with various particle sizes of 100-400 nm and different carboxyl contents, clean surfaces, uniform spherical shapes and good stability can be prepared, thereby increasing the application range and flexibility of the CPS latex microspheres.

[0015] At the same time, the controllable preparation method can reduce material waste, improve production efficiency, thereby reducing costs, and can stably produce polystyrene latex microspheres with different particle sizes or carboxyl densities according to actual needs, facilitating fine control of downstream experiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the implementation mode will be briefly introduced below. Obviously, the drawings described below are only some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 The present invention is a scanning electron microscope (SEM) image and a particle size distribution image of carboxyl polystyrene latex microspheres of different particle sizes, wherein: a is a particle size of 100 nm; b is a particle size of 200 nm; c is a particle size of 300 nm; d is a particle size of 400 nm; e is a distribution image of a particle size of 100 nm; f is a distribution image of a particle size of 200 nm; g is a distribution image of a particle size of 300 nm; and h is a distribution image of a particle size of 400 nm.

[0018] Figure 2 It is a Fourier transform infrared spectrum (FTIR) diagram of the polystyrene (PS) microsphere and the CPS latex microsphere of the present invention.

[0019] Figure 3 This is a diagram showing the hydrated particle sizes of CPS latex microspheres of the present invention before and after being placed at room temperature for three months.

[0020] Figure 4 These are actual photos of the CPS latex microspheres of different hydrated particle sizes of the present invention placed under sunlight before and after being placed at room temperature for three months. DETAILED DESCRIPTION

[0021] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods; the materials and reagents used are reagents and materials that can be obtained from commercial channels unless otherwise specified.

[0023] Example 1 A carboxyl functionalized polystyrene latex microsphere, hereinafter referred to as CPS latex microsphere, and its preparation method is specifically as follows: 1500 g H2O, 250 g styrene (St), 3.5 mL 30 g / L sodium dodecylbenzene sulfonate (LAS), 23.5 mL 50 g / L NaHCO3 solution and 10 g acrylic acid (carboxylation reagent, AA) were added into a three-necked flask, and after nitrogen was passed through to deoxygenate, the mixture was stirred for 40 min to mix evenly, and then heated to reflux at 70 °C; 60 mL 50 g / L KPS solution (potassium persulfate) was injected into the three-necked flask, and the mixture was stirred and refluxed at 70 °C and 300 rpm for 12 h. After the reaction, the mixture was transferred into a dialysis bag (MWCO: 1000 D) and dialyzed and purified for 72 h to obtain carboxyl functionalized polystyrene latex microspheres, such as Figure 1 (a) shown.

[0024] Examples 2 to 6 all prepared carboxyl functionalized polystyrene latex microspheres according to the process of Example 1, and the parameter concentrations involved were the same as in Example 1. The carboxylation reagent in Examples 5 and 6 was methacrylic acid (MAA), as shown in Table 1: Table 1 Preparation of carboxyl functionalized polystyrene latex microspheres

[0025] Example 7 A carboxyl functionalized polystyrene latex microsphere, the preparation method of which is specifically as follows: 1500 g H2O, 250 g styrene (St), 5 mL of 30 g / L sodium dodecylbenzene sulfonate (LAS), 12 mL of 30 g / L NaHCO3 solution and 12 mL of 30 g / L NaOH solution were added into a three-necked flask, stirred for 40 min to mix evenly after nitrogen deoxygenation, and heated to reflux at 70 ℃; 30 mL of 50 g / L KPS solution was injected and added, and the mixture was stirred and refluxed at 70 ℃ and 300 rpm for 5.5 h; 17.5 g of methacrylic acid was slowly injected into the flask and the reaction was continued for 6.5 h. After the reaction, a mixed solution of pure water and ethanol (mixed in a volume ratio of 1:1) was centrifuged and purified to obtain carboxyl functionalized polystyrene latex microspheres.

[0026] Example 8 A carboxyl functionalized polystyrene latex microsphere, the preparation method of which is specifically as follows: 1500 g H2O, 250 g styrene (St), 2.8 mL 30 g / L sodium dodecylbenzene sulfonate (LAS), 12 mL 30 g / L NaHCO3 solution and 12 mL 30 g / L NaOH solution were added into a three-necked flask, stirred for 40 min to mix evenly after nitrogen deoxygenation, and heated to reflux at 70 ℃; 30 mL 50 g / L KPS solution was injected and added, and the mixture was stirred and refluxed at 70 ℃ and 300 rpm for 5.5 h; 17.5 g methacrylic acid was slowly injected into the flask and the reaction was continued for 6.5 h. After the reaction, a mixed solution of pure water and ethanol (mixed in a volume ratio of 1:1) was centrifuged and purified to obtain carboxyl functionalized polystyrene latex microspheres.

[0027] Test Example 1 1. The monomer conversion rates of Examples 1 to 8 were tested respectively to verify the efficiency of the polymer. The conversion rate calculation formula is shown in the following formula (1): (1) Table 2 Related properties of polystyrene latex microspheres with different carboxyl functionalization

[0028] Table 3 Performance test table of polystyrene latex microspheres prepared with different raw material dosages

[0029] As can be seen from Table 2, Examples 1 to 8 can prepare latex microspheres with different carboxyl contents of various particle sizes such as 100, 200, 280, and 380 nm by a one-step method or a two-step method. By changing the type of carboxylation reagent and the amount of raw materials, the surface carboxyl content of the latex microspheres can be controlled, and the monomer conversion rate is as high as 85%, which improves the raw material utilization rate and production efficiency, thereby ensuring product quality.

[0030] At the same time, it can be seen from Table 3 that changing the amount of raw materials will result in the latex microspheres having too large or too small particle sizes, which will affect the quality of the latex microspheres. Therefore, only the present invention can accurately control the preparation of latex microspheres with different carboxyl contents such as 100, 200, 280, and 380 nm through a one-step method or a two-step method, thereby ensuring the effect and consistency of subsequent drug delivery systems, diagnostic reagents, and other applications.

[0031] 2. Use SEM and FT-IR to analyze the morphological characteristics and structural components of CPS latex microspheres.

[0032] like Figure 1 As shown in the scanning electron microscope image, the latex microspheres have good sphericity, uniform distribution and good dispersibility, as shown in the FTIR spectrum ( Figure 2 ), at about 1600 cm −1 , 1500 cm −1 and 1450 cm −1 The three peaks at about 1700 cm −1 and 3500 cm −1 New characteristic peaks of C=O and -OH that are not found in polystyrene (PS) appeared, confirming the successful functionalization of carboxyl groups on the surface of polystyrene microspheres.

[0033] 3. Test the temporal stability of the prepared CPS microspheres with four particle sizes of 100 nm, 200 nm, 280 nm and 380 nm. Observe the sample latex microspheres that have been placed at room temperature for about three months and conduct hydrated particle size tests.

[0034] like Figure 3~4 As shown, there is no obvious precipitation of latex microspheres after three months of storage, and the hydrated particle size remains almost unchanged ( Figure 3 ), the monodispersity is good, indicating that the particle size and monodispersity of CPS microspheres with four particle sizes remain almost unchanged after being placed at room temperature for about three months, and all maintain good stability.

[0035] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A controllable preparation method of carboxyl functionalized polystyrene latex microspheres, characterized in that: The method adopts a one-step method or a two-step method to prepare, comprising the following steps: One-step preparation of CPS latex microspheres: a certain amount of H2O, NaHCO3, NaOH, a trace amount of emulsifier, styrene and functional monomers (acrylic acid or methacrylic acid) are added to a three-necked flask, and after nitrogen is passed through to deoxygenate, the mixture is stirred and mixed evenly, and heated to reflux at 70-90 °C. A certain volume of potassium persulfate solution with a concentration of 20-50 g / L is injected into the flask, and the mixture is stirred and refluxed for 8-20 h. The obtained white emulsion is stored in a wide-mouth plastic bottle at room temperature for later use; CPS latex microspheres were prepared by a two-step method: a certain amount of H2O, NaHCO3, NaOH, a trace amount of emulsifier, and styrene were added to a three-necked flask, the mixture was stirred and mixed evenly after nitrogen deoxygenation, and the mixture was heated to reflux at 70-90 °C. A certain volume of potassium persulfate solution with a concentration of 20-50 g / L was injected into the flask, and after stirring and reflux reaction for 3-6 h, 5.0-30 g of functional monomer acrylic acid or methacrylic acid was injected and added. The stirring and reflux reaction was continued for 4-10 h. The obtained white emulsion was stored in a wide-mouth plastic bottle at room temperature for later use.

2. The controllable preparation method according to claim 1, characterized in that: The particle size is regulated by the dosage of sodium dodecylbenzene sulfonate and potassium persulfate and pH; the carboxyl content on the surface of the latex microspheres is controlled by changing the type and dosage of the carboxylating agent.

3. The controllable preparation method according to claim 1, characterized in that: The pH of the reaction system is regulated by using one or a mixture of NaHCO3 or NaOH, and the concentration of NaHCO3 is 0.02~0.06 g / L.

4. The controllable preparation method according to claim 1, characterized in that: The micro-emulsifier is sodium dodecylbenzene sulfonate with a concentration lower than the critical micelle concentration; the concentration of the sodium dodecylbenzene sulfonate is 0-0.03wt%.

5. The controllable preparation method according to claim 1, characterized in that: The styrene concentration is 10-20wt%; the surface of the microspheres is carboxyl functionalized by using one or a mixture of acrylic acid or methacrylic acid, and the mass ratio of styrene to the functional monomer acrylic acid or methacrylic acid is (15-5):

1.

6. The controllable preparation method according to claim 1, characterized in that: The potassium persulfate is added in an amount of 0.5-3 wt% of styrene, the reaction temperature is 70-90° C., and the stirring speed is 200-400 rpm.

7. The controllable preparation method according to claim 1, characterized in that: The one-step preparation method refers to a method in which the functional monomers acrylic acid or methacrylic acid are stirred evenly with styrene and then added into the reaction system for reaction, and the reaction time is 8 to 20 hours.

8. The controllable preparation method according to claim 1, characterized in that: The two-step preparation method refers to first preparing polystyrene seeds by soap-free emulsion polymerization, and then adding functional monomers acrylic acid or methacrylic acid to the system containing seed microspheres to continue the polymerization reaction for 4 to 10 hours.

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