CN104031210A - Method for preparing quaternary ammonium salt surface-modified monodisperse polystyrene microsphere emulsion - Google Patents

Abstract

The invention relates to a preparation method of a monodisperse polystyrene microsphere emulsion modified on the surface of a quaternary ammonium salt. The invention prepares the monodisperse polystyrene microsphere emulsion with the surface modification of the quaternary ammonium salt by introducing the hydrophilic functional monomer and changing the feeding ratio of styrene and water, so as to realize the effective control of the monodisperse polystyrene microsphere. The present invention uses styrene as the main monomer, dimethyl diallyl ammonium chloride as the functional monomer, methyl methacrylate as the third monomer, potassium persulfate or ammonium persulfate as the initiator, and water as the reaction As a medium, polystyrene microspheres with surface-enriched quaternary ammonium salts were prepared by using soap-free emulsion polymerization in a semi-continuous manner. The present invention does not add any surfactant, organic solvent and inorganic salt in the preparation process, the preparation process is simple, and the cost is low. The dosage and the ratio between the three monomers can be flexibly adjusted between 150nm and 600nm.

Description

Preparation method of monodisperse polystyrene microsphere emulsion modified by quaternary ammonium salt surface

technical field

The invention relates to the field of polymer material synthesis, in particular to a preparation method of a monodisperse polystyrene microsphere emulsion modified on the surface of a quaternary ammonium salt.

Background technique

Surface-functionalized polymer microspheres have received more and more attention because they can be widely used in many fields, such as biochemistry and biomedicine, pharmaceuticals, chromatographic column packing, and clinical testing. So far, polymer microspheres containing different functional groups have been reported, including carboxyl groups (Song J S, Leonid C, Mitchell A, Monodisperse Micrometer-Size Carboxyl-Functionalized Polystyrene Particles Obtained by Two-Stage Dispersion Polymerization, Macromolecules, 2006, 39 :5729-5737), amino (Wang Weicai, Zhang Qi, Zhang Bingbo, etc., preparation of monodisperse superparamagnetic fluorescent PGMA multifunctional microspheres by amination, Science Bulletin, 2007, 52:2477～2481), hydroxyl (CN200810239501.X ), bromine substituent (CN200910070904.0), etc. These surface-functionalized polymer microspheres can be used to immobilize and detect biomacromolecules such as proteins such as antibodies and enzymes.

Introducing different groups on the surface of polymer microspheres, such as hydrophilic hydroxyl or carboxyl groups, can improve the stability and even biocompatibility of polymer microspheres; using surface groups can combine inorganic semiconductor particles and functional organic molecules And the introduction of biomolecules into polymer microspheres endows polymer microspheres with special properties, making them widely used in coatings, photoelectric functional materials, and biomedical materials. Among them, polymer microspheres with cations on the surface have been widely used in flocculants, adhesives, and water-based coatings. Generally, cationic polymer microspheres can be synthesized by conventional emulsion polymerization, core-shell emulsion polymerization and other methods according to different needs. Soap-free emulsion polymerization of hydrophilic and hydrophobic monomers has attracted much attention because it can introduce different functional groups on the surface of polymer microspheres and the surface is clean, and it is also an ideal method for the synthesis of cationic polymer microspheres.

Various functional nanoparticles have become a research hotspot because of their huge potential application value. Introducing quaternary ammonium salts on the surface of nanoparticles is also an important functionalization method, which has broad application prospects. Since it is relatively easy to introduce quaternary ammonium salts on the surface of metal nanoparticles or semiconductor nanoparticles, most of these studies are limited to metal nanoparticles or semiconductor nanoparticles, and there are relatively few studies on the surface quaternization of polymer nanoparticles. .

Chen Xin et al proposed to combine styrene, 4,4'-dimethylacryloyloxy-2,2'-diphenylpropane, 2,2'-bis(2-methylpropionamidine) dihydrochloride and The functional monomer vinylbenzyltrimethylammonium chloride was mixed in a certain proportion, and reacted in a water bath at 75°C for 24 hours by emulsion polymerization to prepare a stable surface-enriched cross-linked polystyrene microsphere emulsion of quaternary ammonium salt ( Chen Xin. The synthesis and characterization of cross-linked polystyrene microspheres enriched with quaternary ammonium salts and their swelling behavior. Acta Polymerica Sinica, 2003, 2: 293-297). Although the particle size of the microspheres prepared by this method is relatively uniform, its application is greatly limited due to the high production cost and the large amount of emulsifier residues that will easily cause adverse effects on product performance and the environment, especially in biological, field of medicine.

In recent years, there is also a patent (CN201110449023.7) on the quaternization of polystyrene. This method is to add cetyltrimethylammonium bromide and potassium persulfate or ammonium persulfate to styrene, absolute ethanol The polymerization reaction is initiated in a mixed solution with deionized water. This method is simple and easy, but because no chemical bond is actually formed between the polystyrene segment and the quaternary ammonium salt modifier, the stability of the material is low, and the application is limited.

Therefore, if the above-mentioned polymerization method can be replaced by conventional soap-free emulsion polymerization to prepare quaternary ammonium salt modified polystyrene microspheres, the polystyrene segment and the quaternary ammonium salt modifier containing unsaturated bonds are introduced The chemically bonded third monomer is expected to overcome the above-mentioned shortcomings and obtain a surface-functionalized polystyrene soap-free emulsion with stable performance.

Contents of the invention

One of the purposes of the present invention is to address the defect that styrene and dimethyl diallyl ammonium chloride are difficult to graft, introduce a third monomer as a bridging segment during the polymerization process, and use secondary feeding And a semi-continuous polymerization method, changing the reaction temperature of the initiation stage and the polymerization stage, and controlling the reaction to proceed smoothly, thereby providing a kind of monodisperse polystyrene microsphere emulsion of quaternary ammonium salt surface modification directly in the water phase Preparation.

The second object of the present invention is to aim at the defect that redundant stabilizers exist on the surface of quaternary ammonium salt modified polystyrene microspheres, by changing the ratio of styrene, water and functional monomers, thereby providing a In the case of , inorganic salt and organic solvent, the polystyrene microsphere emulsion prepared on the surface of the quaternary ammonium salt that can be stored stably is modified.

In order to achieve the purpose of the present invention, the present invention adopts dimethyl diallyl ammonium chloride as functional monomer, provides required functional group while stabilizing emulsion polymerization, and finally obtains stable quaternary ammonium salt modified polystyrene micro ball lotion. In order to ensure that the functional monomers can be chemically bonded on the surface of polystyrene microspheres, the present invention adds a certain amount of third monomer methyl methacrylate, and uses its coupling effect to combine the hydrophobic monomer styrene with the hydrophilic functional The monomers are bridged together, and through the semi-continuous polymerization method, while shortening the polymerization induction period, it ensures the stability of the emulsion during the reaction.

The preparation method of the monodisperse polystyrene microsphere emulsion of quaternary ammonium salt surface modification of the present invention: mix styrene and water by the mass ratio of 1:12～1:7 and stir evenly, according to the described styrene quality Add the third monomer methyl methacrylate at 3% to 8% to the above-mentioned uniformly stirred mixed solution; under an inert atmosphere, add potassium persulfate or persulfuric acid according to 0.5% to 6% of the mass of styrene Ammonium; after reacting for 10 to 50 minutes at a temperature of 77 to 85°C, add dimethyl diallyl ammonium chloride aqueous solution (preferably dimethyl diallyl The mass fraction of ammonium chloride aqueous solution is 30% to 60%); then react at a temperature of 70°C to 75°C for 8 to 24 hours, stop heating and cool to room temperature under stirring to obtain a quaternary ammonium salt enriched on the surface Monodisperse polystyrene microsphere emulsion modified by quaternary ammonium salt surface.

In the preparation process of the present invention, functional monomers are grafted, and methyl methacrylate is introduced as the third monomer to bridge the hydrophobic monomer styrene and the hydrophilic dimethyl diallyl ammonium chloride functional monomer. together; the preparation process adopts a semi-continuous method, and after a period of reaction, the functional monomer dimethyl diallyl ammonium chloride is added; no surfactants, organic solvents and inorganic salts are added during the preparation process to ensure that the quaternary ammonium The surface of the monodisperse polystyrene microsphere emulsion modified by the salt surface is clean, and under the condition that there are no other interfering impurities on the surface of the monodisperse polystyrene microsphere, it is ensured that the monodisperse polystyrene microsphere has good particle size uniformity.

The monodisperse polystyrene microsphere emulsion that the preparation method of the present invention obtains is characterized in that: the monodisperse polystyrene microsphere emulsion of quaternary ammonium salt surface modification does not contain any surfactant, organic Solvent and inorganic salt, and the monodispersity of the surface-modified polystyrene microsphere of the quaternary ammonium salt that forms monodisperse polystyrene microsphere emulsion is good, and the surface of monodisperse polystyrene microsphere enriches a large amount of quaternary ammonium salt , The particle size range of monodisperse polystyrene microspheres is 150nm-600nm.

The present invention prepares a monodisperse polystyrene microsphere emulsion modified on the surface of a quaternary ammonium salt by introducing a hydrophilic functional monomer and changing the feeding ratio of styrene and water. Effective control of the ball. The present invention uses styrene as the main monomer, dimethyl diallyl ammonium chloride as the functional monomer, methyl methacrylate as the third monomer, potassium persulfate or ammonium persulfate as the initiator, and water as the reaction As a medium, polystyrene microspheres enriched with quaternary ammonium salts on the surface were prepared by using soap-free emulsion polymerization in a semi-continuous manner. The method has relatively low requirements on the uniformity of the mechanical stirring speed, no surfactant is required, the preparation process is simple, and the cost is low. The dosage and the ratio between the three monomers can be flexibly adjusted between 150nm and 600nm. Monodisperse polystyrene microspheres surface-modified by quaternary ammonium salts can be used as polymer templates, adhesive matrix or inorganic carrier materials, and have important applications in the construction of photonic crystals, inorganic/organic nanocomposites and micron/nano hollow spheres value.

Compared with the synthetic method of existing polystyrene microsphere emulsion, the present invention has the following advantages:

(1) Compared with the emulsion prepared by traditional emulsion polymerization, the present invention does not need to add any surfactant, the surface of the prepared monodisperse polystyrene microsphere emulsion is clean, the uniformity of particle size is good, and the surface is modified by quaternary ammonium salt .

(2) Compared with the emulsion prepared by dispersion polymerization, the present invention does not need to add dispersants and organic solvents, and the surface of the monodisperse polystyrene microsphere emulsion is clean.

(3) The reaction speed of the preparation method of the present invention is fast, and the emulsion stability is good.

(4) The preparation method of the present invention can obviously shorten the reaction cycle and improve the conversion rate of styrene monomer.

(5) Composition The monodisperse polystyrene microspheres in the monodisperse polystyrene microsphere emulsion obtained by the preparation method of the present invention have a uniform particle size and are obviously monodisperse.

Detailed ways

The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present invention but not to limit the protection scope of the present invention. The implementation conditions adopted in the examples can be further adjusted according to specific requirements, and the implementation conditions not indicated are generally the conditions in routine experiments.

Example 1

Add 5.0g of styrene and 60.0g of distilled water into the reactor, stir and mix evenly, add 0.15g of methyl methacrylate under stirring, ventilate with nitrogen, add 0.30g of potassium persulfate; react at a temperature of 85°C After 50 minutes, add 10.0g mass fraction and be 60% dimethyl diallyl ammonium chloride aqueous solution, then continue to react for 8 hours at a temperature of 75° C.; stop heating and cool to room temperature under stirring to obtain quaternary ammonium Monodisperse Polystyrene Microsphere Emulsions Surface-Modified by Salt. The particle diameter of the monodisperse polystyrene microspheres constituting the monodisperse polystyrene microsphere emulsion modified by the surface of the quaternary ammonium salt is 150 nm.

Example 2

Add 6.0g of styrene and 57.0g of distilled water into the reactor, stir and mix evenly, add 0.3g of methyl methacrylate under stirring, ventilate with nitrogen, add 0.20g of potassium persulfate; react at a temperature of 82°C After 30 minutes, add 8.0g mass fraction and be 60% dimethyl diallyl ammonium chloride aqueous solution, then continue to react for 12 hours at a temperature of 75° C.; stop heating and cool to room temperature under stirring to obtain quaternary ammonium Monodisperse Polystyrene Microsphere Emulsions Surface-Modified by Salt. The particle diameter of the monodisperse polystyrene microspheres constituting the monodisperse polystyrene microsphere emulsion modified by the quaternary ammonium salt surface is 220nm.

Example 3

Add 7.0g of styrene and 54.0g of distilled water into the reactor, stir and mix evenly, add 0.4g of methyl methacrylate under stirring, ventilate with nitrogen, add 0.035g of potassium persulfate; react at a temperature of 80°C After 30 minutes, add 7.5g mass fraction and be the dimethyl diallyl ammonium chloride aqueous solution of 60%, then continue to react for 18 hours at a temperature of 73° C.; stop heating and cool to room temperature under stirring to obtain quaternary ammonium Monodisperse Polystyrene Microsphere Emulsions Surface-Modified by Salt. The particle size of the monodisperse polystyrene microspheres constituting the monodisperse polystyrene microsphere emulsion modified by the surface of the quaternary ammonium salt is 450nm.

Example 4

Add 7.5g of styrene and 52.5g of distilled water into the reactor, stir and mix evenly, add 0.60g of methyl methacrylate under stirring, ventilate with nitrogen, add 0.15g of ammonium persulfate; react at a temperature of 77°C After 10 minutes, add 7.0g mass fraction and be 30% dimethyl diallyl ammonium chloride aqueous solution, then continue reaction at 70 ℃ for 24 hours; stop heating and cool to room temperature under stirring, obtain quaternary ammonium Monodisperse Polystyrene Microsphere Emulsions Surface-Modified by Salt. The particle size of the monodisperse polystyrene microspheres constituting the monodisperse polystyrene microsphere emulsion modified by the quaternary ammonium salt surface is 600nm.

The above-mentioned embodiments are only to illustrate the technical concept and characteristics of the present invention, and its purpose is to allow those familiar with this technology to understand the content of the present invention and implement it accordingly, and cannot limit the protection scope of the present invention with this. The equivalent changes and modifications made by the spirit should fall within the protection scope of the present invention.

Claims (5)

1. a kind of preparation method of the monodisperse polystyrene microsphere emulsion of quaternary ammonium salt surface modification, it is characterized in that: styrene and water are mixed and stirred by the mass ratio of 1:12～1:7, press described 3% to 8% of the mass of styrene is added to the above-mentioned uniformly stirred mixed solution; under an inert atmosphere, potassium persulfate or potassium persulfate or Ammonium sulfate; after reacting at a temperature of 77-85°C for 10-50 minutes, add dimethyl diallyl ammonium chloride aqueous solution according to 0.93-2.0 times the mass of styrene; then at a temperature of 70°C React at ~75°C for 8-24 hours, stop heating and cool to room temperature under stirring to obtain monodisperse polystyrene microsphere emulsion with surface modification of quaternary ammonium salt. 2. The preparation method according to claim 1, characterized in that: the mass fraction of the aqueous solution of dimethyl diallyl ammonium chloride is 30% to 60%. 3. The preparation method according to claim 1, characterized in that: the particle size range of the monodisperse polystyrene microspheres is 150nm-600nm. 4. A monodisperse polystyrene microsphere emulsion modified on the surface of a quaternary ammonium salt, characterized in that: it is obtained by the preparation method of claim 1 or 2. 5. the monodisperse polystyrene microsphere emulsion of quaternary ammonium salt surface modification according to claim 4 is characterized in that: the particle size range of the monodisperse polystyrene microsphere of the quaternary ammonium salt surface modification of composition emulsion 150nm ~ 600nm.