CN108794672B

CN108794672B - Monodisperse polystyrene microsphere and preparation method and application thereof

Info

Publication number: CN108794672B
Application number: CN201810548792.4A
Authority: CN
Inventors: 马士禹; 相雪晨; 郑桂华; 陈宁; 陈喆; 施婷婷
Original assignee: East China Normal University
Current assignee: East China Normal University
Priority date: 2018-05-31
Filing date: 2018-05-31
Publication date: 2020-10-30
Anticipated expiration: 2038-05-31
Also published as: CN108794672A

Abstract

The invention discloses a preparation method of monodisperse polystyrene microspheres, which comprises the following steps of adding micromolecular alcohol to disperse styrene in secondary distilled water under the ultrasonic condition to form uniform and transparent mixed solution; adding initiator, and reacting under stirring to obtain the target product. The product prepared by the invention can be widely used in the light industry market and can also be used in powder and emulsion cosmetics. Compared with the prior art, the polystyrene microsphere prepared by the invention has good monodispersity and strong controllability of particle size, adopts a one-pot reaction, has simple preparation method, can be prepared in batches, does not need to use a stabilizer in the reaction process, and has environment-friendly synthesis process.

Description

Monodisperse polystyrene microsphere and preparation method and application thereof

Technical Field

The invention belongs to the technical field of soap-free emulsion polymerization, and relates to a monodisperse polystyrene microsphere and a preparation method and application thereof.

Background

The emulsion polymerization is a reaction in which a monomer is dispersed in water by means of an emulsifier and mechanical stirring to form an emulsion, and an initiator is added to initiate the polymerization of the monomer, and is an important preparation method for synthesizing a high molecular material. The advantages are that: (1) the polymerization speed is high, and the molecular weight of the product is high; (2) water is used as a dispersant medium, which is beneficial to heat transfer and temperature control; (3) after the reaction reaches high conversion rate, the viscosity of the emulsion system is still very low, the dispersion system is stable, and the continuous operation is easy to control and realize. However, in the traditional emulsion polymerization, after the emulsion is formed into a film, the emulsifier can migrate to the surface of the emulsion film through the polymer bulk phase and be enriched, and then the emulsion can be brought into a final product, and the emulsion is difficult to completely remove by post-treatment processes such as water washing and the like. The factors of isolation, water absorption, seepage and the like in the presence of the emulsifier reduce the water resistance, solvent resistance and mechanical properties of the polymer product, so that the application of the polymer product is limited, and meanwhile, the emulsifier is expensive, so that the product cost is increased. Matsumoto and Ochi (literature) synthesized polystyrene, polymethyl methacrylate and polyvinyl acetate emulsions with monodisperse latex particles in particle size in 1960 in the complete absence of emulsifiers, after which soap-free emulsion polymerization to prepare polymer microspheres developed rapidly. Emulsifier is not added or only trace emulsifier (the concentration of the emulsifier is less than critical micelle concentration CMC) is added in the reaction process, the particle size of the microsphere is larger than that of the conventional emulsion polymerization, the particle size of the latex is single-dispersed, the surface is clean, and the post-treatment of removing the emulsifier is not needed. The product is widely applied to the fields of clinical medicine, cytology, material science, chromatographic separation and the like.

In recent years, the monodisperse polymer microspheres have attracted much attention due to the characteristics of controllable form, adjustable molecular weight, easy introduction of different functional groups on the surface, and the like. In the polymer microspheres, the preparation and application of the polystyrene microspheres are the most extensive, and templates or construction units are provided for the construction of ordered low-dimensional nanostructures.

The Chinese patent with application number 200710098739.0 discloses a method for preparing monodisperse polystyrene microspheres with controllable particle size, which takes styrene as a monomer, potassium persulfate as an initiator, water as a reaction medium, polyvinylpyrrolidone as a stabilizer and adopts a soap-free emulsion polymerization method to prepare the polystyrene microspheres; the particle size range of the prepared monodisperse polystyrene microsphere is 250-1400 nm. Unlike the said patent technology, the present invention introduces small molecular alcohol as surfactant into styrene polymerizing system and needs no stabilizer. Compared with the above patent, the technical advantages of the present invention are mainly embodied in the following aspects: 1) no stabilizer is needed, and no stabilizer in the product is needed to be removed; 2) the raw materials have low toxicity and the preparation method is simple.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a preparation method of monodisperse polystyrene microspheres, which is prepared by taking styrene as a monomer and redistilled water as a solvent through soap-free emulsion polymerization. During preparation, under the ultrasonic condition, adding small molecular alcohol to disperse styrene in secondary distilled water to form uniform and transparent mixed solution; adding initiator, placing the mixed solution in a 70 ℃ water bath, reacting under stirring according to the addition of styrene, distilling with steam for 5-48 hours, and centrifugally separating (alcohol washing and water washing) to obtain the target product. The target product obtained by the invention is the monodisperse polystyrene microsphere with good monodispersity, excellent storage stability and good optical performance.

The invention provides a preparation method of monodisperse polystyrene microspheres; the method specifically comprises the following steps:

step (1): washing styrene with the solution, then washing with the solvent, and carrying out reduced pressure distillation to obtain purified styrene.

Step (2): and (2) adding the purified styrene obtained in the step (1) and the solvent same as the solvent in the step (1) into a container, then dropwise adding small molecular alcohol, and performing ultrasonic treatment until a mixed solution is clear and transparent.

And (3): and (3) adding an initiator into the clear and transparent mixed solution obtained in the step (2).

Step (4); the container was placed in a water bath and stirred for reaction.

And (5): and (4) centrifuging, washing, redispersing and circularly treating the product obtained by the reaction in the step (4), and removing incompletely reacted styrene, initiator and the like to obtain the monodisperse polystyrene microsphere with uniform particle size.

In the step (1), the solution is one of sodium hydroxide solution, alkaline alumina and the like; preferably, it is a sodium hydroxide solution.

In the step (1), the concentration of the solution is 5-10 wt%; preferably, it is 10 wt%.

In the step (1), the purpose of washing the styrene by the solution is to remove a polymerization inhibitor in the styrene, and the standard is that the separated sodium hydroxide is clear and transparent.

In the step (1), the washing times of the solution are 1-3 times; preferably 3 times.

In the step (1), the solvent is 1 or more of secondary distilled water, high purity water and the like so as to reduce the influence of foreign impurities; preferably, it is double distilled water.

In step (1), the purpose of the solvent is to wash the styrene to neutrality.

In the step (1), the washing times of the solvent are 2-4 times; preferably 4 times.

In the step (1), the temperature of the reduced pressure distillation is 18-25 ℃; preferably, it is 25 ℃.

In the step (1), the time of reduced pressure distillation is 20-50 min; preferably, it is 40 min.

In the step (1), the distillate at about 20 ℃ in the reduced pressure distillation process is the purified styrene.

The step (1) further comprises storing the purified styrene in a freezer of a dryer.

In step (2), the container may be a three-neck flask or a flask of other specifications.

In the step (2), the small molecule alcohol refers to C1-C8 alcohol, and the common method comprises the following steps: one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, tert-butanol, etc.; preferably, methanol, ethanol, isopropanol, tert-butanol. The function of the dispersion agent is to reduce the surface tension of distilled water, so that styrene can be conveniently dispersed in the distilled water.

In the step (2), the temperature of the ultrasonic wave is 20-25 ℃; preferably, it is 25 ℃.

In the step (2), the ultrasonic treatment time is 20-30 min; preferably, it is 30 min.

In the step (2), the operation of dropping the small molecular alcohol can also be performed under the ultrasonic condition.

In the step (2), the volume ratio of the solvent to the purified styrene is (100-): (4-5); preferably, it is 100: 4.6.

the micromolecular alcohol is selected as the surface active substance in the step (2), so that compared with the conventional organic substances such as macromolecules and the like, the micromolecular alcohol has low toxicity, small environmental pollution and strong controllability.

In the step (3), the initiator is one or more of potassium persulfate (KPS), Azobisisobutyronitrile (AIBN), dibenzoyl peroxide (BPO) and the like; preferably, it is potassium persulfate (KPS).

In the step (3), the mass ratio of the initiator to the purified styrene is (1-1.5): (40-42); preferably, 1: 40.

in the step (4), the reaction time is generally 5 to 48 hours depending on the content of styrene.

In the step (4), the reaction temperature is 60-75 ℃; preferably 70 deg.c.

In the step (4), the stirring operation can be performed by using an external stirring device or magnetic stirring of the water bath kettle, and the rotating speed is proper.

In the step (5), the particle size of the polystyrene is 120-200 nm; preferably 140 nm.

The invention also provides the monodisperse polystyrene microsphere obtained by the preparation method.

Wherein the particle size of the polystyrene is 120-200 nm; preferably 140 nm.

The invention also provides the application of the polystyrene microspheres in light industry markets and cosmetics in powder and emulsion.

The invention has the beneficial effects that: compared with the prior art, the preparation method of the monodisperse polystyrene microsphere provided by the invention has the following advantages:

(1) the prepared polystyrene microsphere has good monodispersity and strong particle size controllability;

(2) the prepared polystyrene microsphere emulsion has storage stability;

(3) the one-pot method is adopted for reaction, so that the preparation process is simple;

(4) the micromolecular alcohol has low toxicity and little environmental pollution;

(5) no stabilizer is needed, and no stabilizer in the product is needed to be removed;

(6) the invention selects the micromolecular alcohol as the surface active substance, and compared with the prior organic substances such as macromolecules and the like as the surface active substance, the micromolecular alcohol has low toxicity, small environmental pollution and strong controllability;

(7) the product can be prepared in batch.

Drawings

FIG. 1(a) is an electron micrograph of monodisperse polystyrene microspheres prepared in example 1;

FIG. 1(b) is a dynamic light scattering diagram of monodisperse polystyrene prepared in example 1;

FIG. 2(a) is an electron micrograph of monodisperse polystyrene microspheres prepared in example 2;

FIG. 2(b) is a dynamic light scattering diagram of monodisperse polystyrene microspheres prepared in example 2;

FIG. 3(a) is an electron micrograph of monodisperse polystyrene microspheres prepared in example 3;

FIG. 3(b) is a dynamic light scattering diagram of monodisperse polystyrene microspheres prepared in example 3;

FIG. 4(a) is an electron micrograph of monodisperse polystyrene microspheres prepared in example 4;

FIG. 4(b) is a dynamic light scattering diagram of monodisperse polystyrene microspheres prepared in example 4.

Detailed Description

Embodiments of the present invention will be described in detail with reference to the following drawings. The specific examples are implemented on the premise of the technical solution of the present invention, and include detailed implementation and specific operation procedures, but the scope of the present invention is not limited to the following examples.

Example 1

The method for preparing monodisperse polystyrene microspheres in the embodiment comprises the following steps:

4.6mL of purified styrene monomer and 100mL of secondary distilled water are measured and added into a 250mL three-neck flask, the beaker is placed into an ultrasonic instrument (the ultrasonic power is set to be 99 percent, the ultrasonic time is set to be 30min), methanol (the specification of the selected methanol is analytically pure, the content is more than or equal to 99.7 percent) is added while ultrasonic treatment is carried out until the mixed solution becomes uniform, clear and transparent, and the volume of the methanol is recorded to be 175 mL. 0.1013g of potassium persulfate solid powder is weighed and added into a beaker, the beaker is placed in a water bath kettle, the temperature is set to 70 ℃, a magnetic stirring button (the stirring speed is proper and is about 300rmp) is started, the reaction time is controlled to be 6-7 hours, the reaction is finished, and the steam distillation is carried out for 1 hour. And (3) naturally cooling the emulsion under stirring, and treating the product for 3 times (the centrifugal selection rotation speed is 16000rmp, the time is 20min) through the cyclic operation of centrifugal separation ethanol washing, ultrasonic dispersion/centrifugal separation, water washing/ultrasonic dispersion, so as to obtain the target product. The polystyrene microspheres (about 134 nm) prepared in this example are shown in FIG. 1 (containing FIGS. a and b).

Example 2

weighing 4.6mL of purified styrene monomer and 100mL of secondary distilled water, adding the purified styrene monomer and the secondary distilled water into a 250mL three-neck flask, placing the beaker into an ultrasonic instrument (the ultrasonic power is set to be 99 percent, and the ultrasonic time is set to be 30min), adding ethanol (the specification of the selected ethanol is analytically pure, the content is more than or equal to 99.5 percent) while carrying out ultrasonic treatment until the mixed solution becomes uniform, clear and transparent, and recording the volume of the ethanol to be 120 mL. 0.1124g of potassium persulfate solid powder is weighed and added into the mixed solution, the beaker is placed in a water bath kettle, the temperature is set to 70 ℃, a magnetic stirring button is started (the stirring speed is proper and is about 300rmp), the reaction time is controlled to be 6-7 hours, and the water vapor distillation is carried out for 1 hour after the reaction is finished. And (3) naturally cooling the emulsion under stirring, and treating the product for 3 times (the centrifugal selection rotation speed is 16000rmp, the time is 20min) through the cyclic operation of centrifugal separation ethanol washing, ultrasonic dispersion/centrifugal separation, water washing/ultrasonic dispersion, so as to obtain the target product. The polystyrene microspheres (about 140 nm) prepared in this example are shown in FIG. 2 (containing diagrams a and b).

Example 3

4.6mL of purified styrene monomer and 100mL of secondary distilled water are measured and added into a 250mL three-neck flask, the beaker is placed into an ultrasonic instrument (the ultrasonic power is set to be 99 percent, the ultrasonic time is set to be 30min), isopropanol (the specification of the selected isopropanol is analytically pure, the content is more than or equal to 99.7 percent) is added while ultrasonic treatment is carried out until the mixed solution becomes uniform, clear and transparent, and the volume of the isopropanol is recorded to be 90 mL. 0.1052g of potassium persulfate solid powder is weighed and added into the mixed solution, the beaker is placed in a water bath kettle, the temperature is set to 70 ℃, a magnetic stirring button is started (the stirring speed is proper and is about 300rmp), the reaction time is controlled to be 6-7 hours, the reaction is finished, and the steam distillation is carried out for 1 hour. And (3) naturally cooling the emulsion under stirring, and treating the product for 3 times (the centrifugal selection rotation speed is 16000rmp, the time is 20min) through the cyclic operation of centrifugal separation ethanol washing, ultrasonic dispersion/centrifugal separation, water washing/ultrasonic dispersion, so as to obtain the target product. The polystyrene microspheres (about 144 nm) prepared in this example are shown in FIG. 3 (containing diagrams a and b).

Example 4

weighing 4.6mL of purified styrene monomer and 100mL of secondary distilled water, adding the purified styrene monomer and the secondary distilled water into a 250mL three-necked flask, placing the beaker into an ultrasonic instrument (the ultrasonic power is set to be 99 percent, and the ultrasonic time is set to be 30min), adding tert-butyl alcohol (the specification of the selected tert-butyl alcohol is that the chemical purity is higher than or equal to 98.0 percent) while carrying out ultrasonic treatment until the mixed solution becomes uniform, clear and transparent, and recording that the content of the tert-butyl alcohol is 80 mL. Weighing 0.1025g of potassium persulfate solid powder, adding the potassium persulfate solid powder into the mixed solution, placing the beaker in a water bath kettle, setting the temperature to be 70 ℃, starting a magnetic stirring button (the stirring speed is proper and is about 300rmp), controlling the reaction time to be 6-7 hours, finishing the reaction, and distilling with steam for 1 hour. And (3) naturally cooling the emulsion under stirring, and treating the product for 3 times (the centrifugal selection rotation speed is 16000rmp, the time is 20min) through the cyclic operation of centrifugal separation ethanol washing, ultrasonic dispersion/centrifugal separation, water washing/ultrasonic dispersion, so as to obtain the target product. The polystyrene microspheres (about 146 nm) prepared in this example are shown in FIG. 4 (containing diagrams a and b).

The protection of the present invention is not limited to the above embodiments. Variations and advantages that may occur to those skilled in the art may be incorporated into the invention without departing from the spirit and scope of the inventive concept, and the scope of the appended claims is intended to be protected.

Claims

1. A preparation method of monodisperse polystyrene microspheres is characterized by comprising the following steps:

(1) washing styrene with a solution, then washing with a solvent, and carrying out reduced pressure distillation to obtain purified styrene; the solvent is 1 or 2 of secondary distilled water and high-purity water so as to reduce the influence of foreign impurities;

(2) adding the purified styrene obtained in the step (1) and a solvent which is the same as the solvent obtained in the step (1) into a container, then dropwise adding small molecular alcohol, and performing ultrasonic treatment until a mixed solution is clear and transparent; wherein the volume ratio of the solvent to the purified styrene is (100- & lt 110- & gt): (4-5);

(3) adding an initiator into the clear and transparent mixed solution obtained in the step (2); wherein the mass ratio of the initiator to the purified styrene is (1-1.5): (40-42);

(4) placing the container in a water bath, and stirring for reaction;

(5) and (4) centrifuging, washing, redispersing and circularly treating the product obtained by the reaction in the step (4), and removing incompletely reacted styrene and an initiator to obtain the monodisperse polystyrene microsphere with uniform particle size.

2. The method according to claim 1, wherein in the step (1), the solution is one or two of sodium hydroxide solution and alkaline alumina; the concentration of the solution is 5-10 wt%.

3. The method according to claim 1, wherein in the step (1), the temperature of the reduced pressure distillation is 18-25 ℃; the time of the reduced pressure distillation is 20-50 min; in the reduced pressure distillation process, the distillate at 20 ℃ is the purified styrene.

4. The method according to claim 1, wherein in the step (2), the small molecule alcohol is C1-C8 alcohol, and comprises: one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, and tert-butanol.

5. The method according to claim 1, wherein in the step (2), the temperature of the ultrasound is 20-25 ℃; the ultrasonic treatment time is 20-30 min.

6. The method according to claim 1, wherein in the step (3), the initiator is one or more of potassium persulfate KPS, azobisisobutyronitrile AIBN and dibenzoyl peroxide BPO.

7. The method according to claim 1, wherein in the step (4), the temperature of the reaction is 60-75 ℃; the reaction time is 5-48 hours.

8. The method as claimed in claim 1, wherein in step (5), the particle size of the polystyrene is 120-200 nm.

9. Monodisperse polystyrene microspheres obtainable by a process according to any one of claims 1 to 8.

10. The polystyrene microsphere of claim 9, wherein the polystyrene particle size is 120-200 nm.

11. Use of the polystyrene microspheres of claim 9 in light industry markets, powder and emulsion cosmetics.