High ultraviolet-visible light shielding polystyrene hollow microsphere with Janus structure as well as preparation method and application thereof

Abstract

The invention discloses a high ultraviolet-visible light shielding polystyrene hollow microsphere with a Janus structure as well as a preparation method and application of the high ultraviolet-visible light shielding polystyrene hollow microsphere. The polystyrene hollow microspheres with the Janus structure are synthesized through a one-pot method, toxic organic solvents and a large number of toxic chemicals are not used in the synthesis process, and the method is simple in process, environmentally friendly and low in cost. Compared with an existing titanium dioxide product, the prepared polystyrene hollow microsphere with the Janus structure has more excellent ultraviolet-visible light shielding performance and higher structure and performance designability, the ultraviolet absorption rate of the polystyrene hollow microsphere is further improved after preparation conditions are optimized, and it is proved that the polystyrene hollow microsphere with the Janus structure has higher practicability.

Description

Technical Field

[0001] The present invention relates to the field of polymer materials, and in particular to polystyrene hollow microspheres with a Janus structure and high ultraviolet-visible light shielding, as well as a preparation method and application thereof. Background Art

[0002] In many industrial fields, the choice of light-shielding materials plays a key role in product performance and cost control. Traditional light-shielding materials, such as titanium dioxide, are expensive, dense, and complex to process. These drawbacks are particularly limiting in applications requiring lightweight and cost-effective materials. Therefore, the search for alternative materials with superior performance and greater cost-efficiency has become a research priority in this area.

[0003] Hollow microspheres, due to the significant difference in refractive index between their shell material and the internal cavity (1.6 / 1.0), have a strong refraction, reflection, and scattering effect on light, resulting in excellent light-shielding effects. Furthermore, due to the internal cavity structure of the microspheres, they have a lower density and a larger specific surface area. This property can reduce material weight while also providing other potential applications, such as thermal insulation, catalysis, and adsorption.

[0004] As a new functional material, polystyrene hollow microspheres, with their unique structural designability and adjustable performance, are gaining widespread application in a variety of fields, including paper coating, building materials, lightweight composite materials, the automotive industry, plastic modification, and cosmetics. For example, in papermaking, hollow microspheres replace some titanium dioxide by imparting greater whiteness and opacity to paper, significantly reducing paper weight and improving cost-effectiveness.

[0005] Currently, the preparation of common polystyrene hollow microspheres has drawbacks such as complex processes, the addition of large amounts of chemicals, high energy consumption, low strength, low UV shielding capabilities, and a simple structure. Therefore, developing a novel preparation method to address these issues is of great significance for applications requiring high UV-visible light shielding, lightweight, cost-effectiveness, and anisotropic construction. Summary of the Invention

[0006] The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and provide a polystyrene hollow microsphere with a Janus structure and high UV-visible light shielding.

[0007] Another object of the present invention is to provide a method for preparing the polystyrene hollow microspheres with high UV-visible light shielding properties having a Janus structure.

[0008] Another object of the present invention is to provide an application of the polystyrene hollow microspheres with high UV-visible light shielding and having a Janus structure.

[0009] The purpose of the present invention is achieved through the following technical solutions:

[0010] A method for preparing polystyrene hollow microspheres with a Janus structure and high UV-visible light shielding performance comprises the following steps:

[0011] Ammonium persulfate and polyvinyl pyrrolidone are added to an ethanol solution, stirred, heated in a water bath, styrene is added for a first stirring reaction, and then styrene is added for a second stirring reaction. After the reaction, 2-hydroxy-4-methoxybenzophenone is added for a third stirring reaction. After the reaction, the solution is washed, centrifuged, rotary evaporated, and dried to obtain highly ultraviolet-visible light shielding polystyrene hollow microspheres with a Janus structure.

[0012] The mass ratio of the ammonium persulfate to polyvinyl pyrrolidone is 10-20:1, preferably 12.5:1.

[0013] The concentration of the ethanol solution is 80-90%.

[0014] The stirring is performed for 10 to 20 minutes.

[0015] The water bath heating temperature is 65-75°C, preferably 70°C.

[0016] The ratio of styrene to ammonium persulfate added in the first stirring reaction is 1-2 mL: 0.1 g.

[0017] The first stirring reaction time is 1 to 3 hours, preferably 2 hours.

[0018] The ratio of styrene to ammonium persulfate added in the second stirring reaction is 1-2 mL:0.1 g.

[0019] The second stirring reaction time is 12 to 16 hours, preferably 14 hours.

[0020] The amount of 2-hydroxy-4-methoxybenzophenone added in the third stirring reaction is such that the final concentration is 0.1 to 10 mmol / L, preferably 0.5 to 8 mmol / L.

[0021] The third stirring reaction time is 1 to 3 hours, preferably 2 hours.

[0022] A polystyrene hollow microsphere with a Janus structure and high ultraviolet-visible light shielding is prepared by the above preparation method.

[0023] The application of the highly ultraviolet-visible light shielding polystyrene hollow microspheres with a Janus structure in the preparation of anti-ultraviolet coatings.

[0024] The highly ultraviolet-visible light shielding polystyrene hollow microspheres with a Janus structure are used in the preparation of materials with ultraviolet light absorbing function.

[0025] The present invention has the following advantages and effects compared to the prior art:

[0026] (1) The present invention synthesizes polystyrene hollow microspheres with a Janus structure through a one-pot method. No toxic organic solvents and a large amount of toxic chemicals are used in the synthesis process. The process is simple, environmentally friendly and low in cost.

[0027] (2) Compared with existing titanium dioxide products, the polystyrene hollow microspheres with Janus structure prepared by the present invention have better ultraviolet-visible light shielding performance and stronger structural and performance designability. After optimizing the preparation conditions, their ultraviolet absorption rate is further improved, proving that they have stronger practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Field emission scanning electron microscope and transmission scanning electron microscope photos of comparative example 1 of the present invention.

[0029] Figure 2 Field emission scanning electron microscope and transmission scanning electron microscope photos of comparative example 2 of the present invention.

[0030] Figure 3 Field emission scanning electron microscope and transmission scanning electron microscope photos of comparative example 3 of the present invention.

[0031] Figure 4 Field emission scanning electron microscope and transmission scanning electron microscope photos of Example 1 of the present invention.

[0032] Figure 5 Field emission scanning electron microscope and transmission scanning electron microscope photos of Example 2 of the present invention.

[0033] Figure 6 The graph shows the UV-visible light transmittance results of Examples 1 to 2 of the present invention and Comparative Examples 1 to 3.

[0034] Figure 7 The infrared spectra of Example 1 and Comparative Example 4 of the present invention are shown. DETAILED DESCRIPTION

[0035] The present invention will be described in further detail below with reference to the embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0036] If specific experimental conditions are not specified in the following embodiments, conventional experimental conditions or those recommended by the reagent company will generally be used. Materials and reagents used were commercially available unless otherwise specified.

[0037] Example 1

[0038] This embodiment provides a method for producing highly ultraviolet-visible light shielding polystyrene hollow microspheres with a Janus structure, which specifically includes the following steps:

[0039] (1) Preparation of initiation solution

[0040] Take 0.1 g of ammonium persulfate and 0.008 g of polyvinyl pyrrolidone, add a mixture of 25 ml of ethanol and 5 ml of water, continue stirring for 15 minutes, and then pour into a round-bottom flask.

[0041] (2) One-pot preparation of polystyrene hollow microspheres

[0042] The round-bottom flask was placed in a 70°C water bath, 1 ml of styrene was added, and the reaction was continued with stirring for 2 hours. Then, 1 ml of styrene was added, and the stirring was continued for 14 hours. Then, 2-hydroxy-4-methoxybenzophenone was added to make the final concentration of 2-hydroxy-4-methoxybenzophenone in the entire reaction system 8 mmol / L. The reaction was continued for 2 hours. When the reaction was completed, polystyrene hollow microspheres were obtained.

[0043] (3) Purification of microspheres

[0044] The microspheres synthesized in step (2) were removed, resuspended in an ethanol / water system, and repeatedly centrifuged, and finally centrifuged with water. The microsphere solution was evaporated using a rotary evaporator. The highly concentrated microsphere suspension after rotary evaporation was placed in an ultra-low temperature freezer for 48 hours, and then placed in a freeze drying oven for 72 hours to obtain a highly UV-visible light shielding polystyrene hollow microsphere powder having a Janus structure.

[0045] (4) Preparation of light-shielding suspension

[0046] The polystyrene hollow microspheres were added into deionized water, and the mixture was thoroughly ultrasonicated and stirred to prepare a microsphere suspension with a mass fraction of 0.01 wt%.

[0047] Example 2

[0048] The preparation was carried out according to the method of Example 1, except that the final concentration of 2-hydroxy-4-methoxybenzophenone in step (2) was adjusted from 8 mmol / L to 0.5 mmol / L. The remaining steps were the same as those of Example 1 to produce highly UV-visible light shielding polystyrene hollow microspheres having a Janus structure.

[0049] Comparative Example 1

[0050] The preparation was carried out according to the method of Example 1, except that the continuous stirring in step (2) was adjusted from 14 hours to 4 hours, and 2-hydroxy-4-methoxybenzophenone was not added. The remaining steps were the same as those of Example 1 to obtain polystyrene microspheres.

[0051] Comparative Example 2

[0052] Preparation of polystyrene microspheres with an incomplete hollow structure. The preparation was carried out according to the method of Example 1, except that the continuous stirring in step (2) was adjusted from 14 hours to 10 hours, and 2-hydroxy-4-methoxybenzophenone was not added. The remaining steps were the same as those of Example 1 to produce polystyrene microspheres with an incomplete hollow structure.

[0053] Comparative Example 3

[0054] The preparation was carried out according to the method of Example 1, except that 2-hydroxy-4-methoxybenzophenone was not added in step (2). The remaining steps were the same as those of Example 1 to obtain polystyrene hollow microspheres with a Janus structure.

[0055] Comparative Example 4

[0056] Titanium dioxide powder was placed in deionized water and stirred thoroughly to prepare a suspension with a mass fraction of 0.01 wt%.

[0057] Example 3 Characterization Test

[0058] 3.1 Field emission scanning electron microscopy and transmission scanning electron microscopy analysis

[0059] In order to confirm the microstructure of the microspheres synthesized in the examples and comparative examples, field emission scanning electron microscopy and projection scanning electron microscopy were used to characterize and detect them. The results are as follows: Figures 1 to 5 shown.

[0060] The experimental results show that in Comparative Example 1, polystyrene microspheres have been formed with a wide particle size distribution; in Comparative Example 2, polystyrene microspheres with highly uniform particle size were successfully synthesized, and some of the microspheres began to form a cavity structure; in Comparative Example 3, polystyrene hollow microspheres with highly uniform particle size and a Janus structure were successfully synthesized; and in Examples 1 and 2, highly uniform particle size, highly UV-visible light-shielding polystyrene hollow microspheres with a Janus structure were successfully synthesized, and their morphology did not change significantly compared to the polystyrene hollow microspheres in Comparative Example 3. In addition, based on the asymmetric structure of the polystyrene hollow microspheres in Examples 1 and 2, compared with traditional regular polystyrene hollow microspheres, the structure and performance are more designable and have greater development potential in many fields.

[0061] 3.2 Comparison of shading performance

[0062] In order to determine the light-shielding properties of the synthesized microspheres, the light transmittance of a 0.01 wt% suspension of the microspheres was measured by UV spectrophotometer. The experimental results are shown in Figure 2. Figure 6 shown.

[0063] The experimental results show that with the gradual formation of the polystyrene microsphere cavity structure, the ultraviolet-visible light shielding performance of the microparticles is gradually enhanced. In Comparative Example 3, the ultraviolet-visible light shielding performance of the polystyrene hollow microspheres with a Janus structure has been significantly improved and has exceeded titanium dioxide. In Examples 1 and 2, since 2-hydroxy-4-methoxybenzophenone is loaded on the surface of the polystyrene hollow microspheres, its ultraviolet shielding ability is further improved, especially it can pass through the ozone layer and reach the UVA and UVB ultraviolet rays on the earth's surface. In addition, Example 1 is more effective in ultraviolet shielding than Example 2, indicating that the loading amount of the latter 2-hydroxy-4-methoxybenzophenone has not reached saturation, and it is more appropriate to add 8mmol / L of 2-hydroxy-4-methoxybenzophenone in the later stage of the synthesis reaction.

[0064] 3.3 Infrared spectroscopy

[0065] The microspheres synthesized in the examples and comparative examples were characterized by infrared spectroscopy. Figure 7 shown.

[0066] The experimental results show that compared with comparative example 3, in Example 1, 3200-3600 cm -1 and 1660cm -1 and (C=O) are the characteristic absorption peaks of the hydroxyl group (-OH) and keto group (C=O) of 2-hydroxy-4-methoxybenzophenone, indicating that 2-hydroxy-4-methoxybenzophenone has been successfully loaded on the surface of polystyrene hollow microspheres to form highly UV-visible light shielding polystyrene hollow microspheres with Janus structure.

[0067] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for preparing polystyrene hollow microspheres with high UV-visible light shielding having a Janus structure, characterized in that The steps include: Ammonium persulfate and polyvinyl pyrrolidone are added to an ethanol solution, stirred, heated in a water bath, styrene is added for a first stirring reaction, and then styrene is added for a second stirring reaction. After the reaction, 2-hydroxy-4-methoxybenzophenone is added for a third stirring reaction. After the reaction, the solution is washed, centrifuged, rotary evaporated, and dried to obtain highly ultraviolet-visible light shielding polystyrene hollow microspheres with a Janus structure.

2. The method for preparing polystyrene hollow microspheres with high UV-visible light shielding having a Janus structure according to claim 1, characterized in that: The mass ratio of the ammonium persulfate to the polyvinyl pyrrolidone is 10-20:

1.

3. The method for preparing polystyrene hollow microspheres with high UV-visible light shielding having a Janus structure according to claim 1, characterized in that The concentration of the ethanol solution is 80-90%; The stirring is performed for 10 to 20 minutes; The temperature of the water bath heating is 65-75°C.

4. The method for preparing polystyrene hollow microspheres with high UV-visible light shielding having a Janus structure according to claim 1, characterized in that: The ratio of styrene to ammonium persulfate added in the first stirring reaction is 1-2 mL: 0.1 g; The first stirring reaction time is 1 to 3 hours.

5. The method for preparing polystyrene hollow microspheres with high UV-visible light shielding having a Janus structure according to claim 1, characterized in that: The ratio of styrene to ammonium persulfate added in the second stirring reaction is 1-2 mL: 0.1 g; The second stirring reaction time is 12 to 16 hours, preferably 14 hours.

6. The method for preparing polystyrene hollow microspheres with high UV-visible light shielding having a Janus structure according to claim 1, characterized in that: The amount of 2-hydroxy-4-methoxybenzophenone added in the third stirring reaction is such that the final concentration is 0.1 to 10 mmol / L; The third stirring reaction time is 1 to 3 hours.

7. The method for preparing polystyrene hollow microspheres with high UV-visible light shielding having a Janus structure according to claim 1, characterized in that: The amount of 2-hydroxy-4-methoxybenzophenone added is such that the final concentration is 0.5 to 8 mmol / L.

8. A polystyrene hollow microsphere with high UV-visible light shielding and a Janus structure, prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the polystyrene hollow microspheres with a Janus structure and high UV-visible light shielding properties as claimed in claim 8 in the preparation of UV-proof coatings.

10. Use of the polystyrene hollow microspheres with a Janus structure and high UV-visible light shielding according to claim 8 in preparing a material having the function of absorbing UV rays.

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