β-ZnS nanoparticles and their preparation and application

Abstract

The present application discloses a β-zinc sulfide nanoparticle and its preparation and application. The preparation method comprises the following steps: S1. dispersing a zinc salt, a dopant and a complexing agent in water, and adjusting the pH to 8-10 to obtain a zinc complex sol; S2. adding a sulfur source solution to the zinc complex sol, performing a primary heating reaction, and obtaining a ZnS precursor sol; S3. adding a template agent to the ZnS precursor sol, performing a secondary heating reaction, and washing to obtain a ZnS hydrothermal product; S4. treating the ZnS hydrothermal product with plasma to obtain β-zinc sulfide nanoparticles. The present application solves the performance contradiction between whiteness and ultraviolet absorptivity of zinc sulfide for glass fiber reinforced polyester engineering plastics through a sol-hydrothermal synergistic process, combined with element doping and morphology control, and achieves the synergistic optimization of high whiteness (≥95%) and high ultraviolet absorptivity (≥99%) of zinc sulfide.

Description

Technical Field

[0001] The present invention relates to the field of plastics, and in particular to beta zinc sulfide nanoparticles and preparation and application thereof. Background Art

[0002] As one of the raw materials for glass fiber reinforced polyester engineering plastics, zinc sulfide's whiteness and UV absorption rate have a significant impact on these plastics. The reason is that high-whiteness β-zinc sulfide can give engineering plastics excellent appearance quality and can be used as a base pigment in combination with other pigments; while its high UV absorption rate can prevent polyester engineering plastics from degrading under ultraviolet light, thereby extending the service life of polyester engineering plastics.

[0003] However, existing technologies cannot simultaneously improve the whiteness and UV absorptivity of zinc sulfide. The reason is that high whiteness requires a smooth surface and a complete crystal lattice to reduce light scattering and impurity absorption, which negatively affect UV absorptivity. High UV absorptivity can only be achieved by increasing the specific surface area (such as nano-crystallization and porosity) or introducing defects, which reduces whiteness. As a result, zinc sulfide prepared by existing technologies has a performance bottleneck (whiteness <90%, UV absorptivity <95%).

[0004] Therefore, it is necessary to provide a preparation method of zinc sulfide with high whiteness and high ultraviolet absorption rate to improve the application performance of glass fiber reinforced polyester engineering plastics. Summary of the Invention

[0005] In view of the defects in the prior art, the present invention proposes a β-zinc sulfide nanoparticle and its preparation and application, so as to solve the problem of how to simultaneously improve the whiteness and ultraviolet absorption rate of the β-zinc sulfide nanoparticle.

[0006] In order to solve the above technical problems, this application provides the following technical solutions.

[0007] In a first aspect, the present application provides a method for preparing β-zinc sulfide nanoparticles, comprising the following steps:

[0008] S1. The zinc salt, dopant and complexing agent are dispersed in water and the pH is adjusted to 8-10 to obtain a zinc complex sol;

[0009] S2. A sulfur source solution is added to the zinc complex sol and a heating reaction is performed to obtain a ZnS precursor sol;

[0010] S3. A template is added to the ZnS precursor sol, and the reaction is heated twice, and after washing, a ZnS hydrothermal product is obtained;

[0011] S4. Treating the ZnS hydrothermal product with plasma to obtain β-zinc sulfide nanoparticles.

[0012] Preferably, the dopant includes one or more of aluminum salt and magnesium salt; the molar amount of the dopant is 1-3% of the zinc salt.

[0013] Preferably, the temperature of the primary heating reaction is 50-80°C.

[0014] Preferably, the final temperature of the secondary heating is 150-300° C., and the heating rate of the secondary heating is 2-5° C. / min.

[0015] Preferably, the plasma treatment step is: subjecting the ZnS hydrothermal product to plasma treatment at -5 to 5° C. for 10 to 30 minutes in a carbon and / or fluorine-containing atmosphere.

[0016] Preferably, the washing process is: washing with ethanol and water alternately.

[0017] Preferably, the template agent includes one or more of CTAB and P123; the zinc salt includes one or more of Zn(NO3)2 and ZnSO4; the sulfur source includes one or more of thiourea and Na2S; and the complexing agent includes one or more of citric acid and EDTA.

[0018] In a second aspect, the present application provides a β-zinc sulfide nanoparticle.

[0019] In a third aspect, the present application provides a glass fiber reinforced polyester engineering plastic masterbatch containing β-zinc sulfide nanoparticles.

[0020] Preferably, the added amount of the β-zinc sulfide nanoparticles is 0.5-2 wt % of the glass fiber reinforced polyester engineering plastic masterbatch.

[0021] In summary, compared with the prior art, the present invention achieves the following technical effects: This application solves the performance contradiction between whiteness and ultraviolet absorption rate of zinc sulfide for glass fiber reinforced polyester engineering plastics through a sol-hydrothermal collaborative process, combined with element doping and morphology control, and realizes the synergistic optimization of high whiteness (≥95%) and high ultraviolet absorption rate (≥99%) of zinc sulfide. DETAILED DESCRIPTION

[0022] To help those skilled in the art better understand the present invention, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present invention.

[0023] The present application provides a method for preparing β-zinc sulfide nanoparticles, comprising the following steps:

[0024] S1. The zinc salt, dopant and complexing agent are dispersed in water and the pH is adjusted to 8-10 to obtain a zinc complex sol;

[0025] S2. A sulfur source solution is added to the zinc complex sol and a heating reaction is performed to obtain a ZnS precursor sol;

[0026] S3. A template is added to the ZnS precursor sol, and the reaction is heated twice, and after washing, a ZnS hydrothermal product is obtained;

[0027] S4. Treating the ZnS hydrothermal product with plasma to obtain β-zinc sulfide nanoparticles.

[0028] In this application, steps S1 and S2 achieve uniform doping through a sol-gel method, and step S3 precisely controls the morphology and pore structure of the material through a hydrothermal method to regularize the surface morphology. Then, step S4 performs plasma treatment to reduce the surface energy of the material. By adjusting the raw materials and the process described above, the performance contradiction of simultaneously improving the whiteness and ultraviolet absorption rate of zinc sulfide nanoparticles is overcome. The advantages and mechanisms of the obtained β-zinc sulfide nanoparticles are as follows:

[0029] 1. The β-zinc sulfide nanoparticles of the present application have a regular cubic morphology. Compared with α-zinc sulfide, their surface roughness is lower, which can reduce light scattering and improve the whiteness of the material;

[0030] 2. The β-zinc sulfide nanoparticles of the present application have a porous structure and a large specific surface area, which enhances the ability to capture ultraviolet light. In addition, the porous structure of the β-zinc sulfide nanoparticles of the present application has smooth pore walls, which reduces light scattering and improves the whiteness of the material.

[0031] 3. The β-zinc sulfide nanoparticles of this application have a small particle size and a stable lattice structure. While reducing surface defects, they also introduce shallow energy level defects, thereby improving the whiteness and ultraviolet absorption rate of the material.

[0032] In the present application, the reason why the β-zinc sulfide nanoparticles have a porous cubic morphology with smooth pore walls is that the ZnS precursor sol is hydrothermally reacted with the template agent, which can precisely control the particle morphology and pore structure; the reason why the β-zinc sulfide nanoparticles have a small particle size is that the doping elements inhibit grain growth to form uniform small particles; the reason why the β-zinc sulfide nanoparticles have a stable lattice structure and introduce shallow energy level defects while reducing surface defects is that the doping elements are uniformly distributed through the sol method.

[0033] This application controls both raw materials and processes, and compared with the single sol method, it overcomes the defect of low whiteness, and compared with the single hydrothermal method, it overcomes the difficulty of improving whiteness and ultraviolet absorption performance due to insufficient defect control.

[0034] Among them, step S1 is the preparation of zinc complex sol, and the role of the complexing agent is to coordinate with Zn 2+ The formation of a stable complex is a physical and chemical coordination process, rather than a traditional chemical reaction. The reaction principle is that zinc salt (such as Zn(NO3)2) dissociates into Zn in water. 2+ , complexing agents (such as citric acid) bind to Zn through coordination bonds 2+ Forming a stable complex sol, adjusting the pH to 8-10 can enhance the coordination ability of the complexing agent and avoid Zn 2+ Premature hydrolysis generates Zn(OH)2 precipitate.

[0035] Step S2 is the preparation of ZnS precursor sol, the reaction equation is:

[0036] Zn 2+ +S 2- →ZnS↓; the reaction principle is that the sulfur source (such as Na2S) provides S 2- , and Zn 2+ Combined to form ZnS nanoparticles. One heating (50-80℃) promotes the decomposition of the sulfur source and the nucleation of ZnS to form a uniform precursor sol.

[0037] Step S3 is the preparation of the ZnS hydrothermal product. The reason is: the role of the template (such as CTAB, P123) in the hydrothermal reaction is to regulate the morphology and pore structure of ZnS. It is a physical template-guided process and does not involve the breaking or formation of chemical bonds. This step is mainly the crystal growth and self-assembly of the ZnS precursor under the guidance of the template. It belongs to physical structure regulation and has no clear chemical reaction formula; the reaction principle is: the template (such as CTAB) forms micelles through self-assembly, guiding the ZnS precursor to grow in a directional manner on its surface, forming a porous cubic morphology. Secondary heating (150-300℃) provides energy to promote crystal growth, and the heating rate (2-5℃ / min) is controlled to ensure morphological regularity.

[0038] Step S4 is plasma treatment. Plasma treatment is a physical surface modification process that introduces low surface energy groups (such as -CH3, -CF3) by bombarding the material surface with high-energy particles. It is a surface physical and chemical modification without traditional chemical reaction formulas. The reaction principle is: low-temperature plasma (-5 to 5°C) bombards the ZnS surface in a carbon / fluorine-containing atmosphere (such as CH4, C2F6), breaking its surface chemical bonds and grafting low surface energy groups (such as -CH3, -CF3), thereby reducing surface energy and reducing light scattering.

[0039] In some embodiments, the dopant includes one or more of aluminum salt and magnesium salt; the molar amount of the dopant is 1-3% of the zinc salt.

[0040] In some embodiments, the dopant is a mixture of aluminum salt and magnesium salt; in this embodiment, Al3+ Doping can reduce the lattice spacing, introduce defect energy levels, and enhance ultraviolet absorption. At the same time, Al 3+ It inhibits grain growth, forms uniform small particles, and improves whiteness; while Mg 2+ Can stabilize Al 3+ The lattice structure of the doped material reduces defects and introduces shallow energy level defects to synergistically enhance UV absorption.

[0041] In this embodiment, the final temperature and heating rate of the hydrothermal reaction are controlled. At this heating rate, it is beneficial to obtain a regular cubic morphology with a smooth surface and reduce light scattering. Compared with high-temperature calcination, the present application performs a low-temperature hydrothermal reaction at 150-300°C, which avoids grain coarsening and increased surface defects caused by high temperature, and is beneficial to maintaining high whiteness and high ultraviolet absorption rate.

[0042] In some embodiments, the temperature of the primary heating reaction is 50-80°C.

[0043] In some embodiments, the final temperature of the secondary heating is 150-300° C., and the heating rate of the secondary heating is 2-5° C. / min.

[0044] In some embodiments, the plasma treatment step is: plasma-treating the ZnS hydrothermal product at -5 to 5° C. for 10 to 30 minutes in a carbon and / or fluorine-containing atmosphere.

[0045] In this embodiment, low-temperature plasma treatment is used to treat the surface of β-ZnS particles, introducing low-surface-energy groups (such as -CH3 and -CF3). This reduces the surface energy of the material, and the surface modification layer reduces light scattering and improves whiteness. Specifically, the β-ZnS particles after the hydrothermal reaction are dried and placed in a plasma treatment chamber. A carbon- or fluorine-containing gas (such as methane or hexafluoroethane) is introduced, and the particles are treated under low-temperature (-5 to 5°C) plasma conditions for 10 to 30 minutes.

[0046] In some embodiments, the washing process is: washing with ethanol and water alternately.

[0047] In this embodiment, the hydrothermal product is washed alternately with ethanol / water to remove the template and impurity ions.

[0048] In some embodiments, the template agent includes one or more of CTAB and P123; the zinc salt includes one or more of Zn(NO3)2 and ZnSO4; the sulfur source includes one or more of thiourea and Na2S; and the complexing agent includes one or more of citric acid and EDTA.

[0049] In this application, the content of the template agent affects the pore size and specific surface area of ​​the ZnS hydrothermal product. Under the definition of this application, the pore size is 10-50nm and the specific surface area is ≥50m2 / g of hydrothermal product.

[0050] The present application provides a β-zinc sulfide nanoparticle.

[0051] The present application provides a glass fiber reinforced polyester engineering plastic masterbatch containing β-zinc sulfide nanoparticles.

[0052] In some embodiments, the added amount of β-zinc sulfide nanoparticles is 0.5-2 wt % of the glass fiber reinforced polyester engineering plastic masterbatch.

[0053] The present solution is further described below through specific implementation methods.

[0054] Example 1

[0055] A method for preparing β-zinc sulfide nanoparticles comprises the following steps:

[0056] S1. Dissolve 2.97 g Zn(NO3)2·6H2O (0.01 mol), 0.05 g Al(NO3)3 (0.0002 mol), and 0.02 g Mg(NO3)2 (0.0001 mol) in 100 mL of water, add 0.5 g citric acid, and adjust the pH to 9 to form a zinc-aluminum-magnesium sol;

[0057] S2. 3.8 g of thiourea solution was added dropwise to the sol and stirred at 70 ° C for 2 hours to obtain a ZnS precursor sol;

[0058] S3. 0.1 g of CTAB was added to the ZnS precursor sol, transferred to a hydrothermal reactor, and heated to 180°C at 2°C / min for 12 hours. After natural cooling, the mixture was washed alternately with water and ethanol to obtain a ZnS hydrothermal product.

[0059] S4. After drying the ZnS hydrothermal product, place it in a plasma treatment chamber, introduce methane, and treat it under plasma at -5°C for 10 minutes to obtain β-zinc sulfide nanoparticles.

[0060] Example 2

[0061] A method for preparing β-zinc sulfide nanoparticles comprises the following steps:

[0062] S1. Dissolve 2.97g ZnSO4, 0.05g AlCl3, and 0.02g MgCl2 in 100mL of water, add 0.5g EDTA, and adjust the pH to 10 to form a zinc-aluminum-magnesium sol;

[0063] S2. 3.8 g of Na2S solution was added dropwise to the sol and stirred at 60 ° C for 2 hours to obtain a ZnS precursor sol;

[0064] S3. 0.1 g of P123 was added to the ZnS precursor sol, transferred to a hydrothermal reactor, heated to 200 ° C at 5 ° C / min for 18 hours, cooled naturally, and washed alternately with water and ethanol to obtain a ZnS hydrothermal product;

[0065] S4. After drying the ZnS hydrothermal product, place it in a plasma treatment chamber, introduce methane, and treat it under plasma at -5°C for 10 minutes to obtain β-zinc sulfide nanoparticles.

[0066] Example 3

[0067] A method for preparing β-zinc sulfide nanoparticles comprises the following steps:

[0068] S1. Dissolve 2.97 g Zn(NO3)2·6H2O, 0.2 g Al(NO3)3, and 0.08 g Mg(NO3)2 in 100 mL of water, add 0.5 g citric acid, and adjust the pH to 9 to form a zinc-aluminum-magnesium sol;

[0069] S2. 3.8 g of thiourea solution was added dropwise to the sol and stirred at 70 ° C for 2 hours to obtain a ZnS precursor sol;

[0070] S3. 0.1 g of CTAB was added to the ZnS precursor sol, transferred to a hydrothermal reactor, and heated to 180°C at 2°C / min for 12 hours. After natural cooling, the mixture was washed alternately with water and ethanol to obtain a ZnS hydrothermal product.

[0071] S4. After drying the ZnS hydrothermal product, place it in a plasma treatment chamber, introduce methane, and treat it under plasma at -5°C for 10 minutes to obtain β-zinc sulfide nanoparticles.

[0072] Example 4

[0073] A method for preparing β-zinc sulfide nanoparticles comprises the following steps:

[0074] S1. Dissolve 2.97 g Zn(NO3)2·6H2O, 0.01 g Al(NO3)3, and 0.004 g Mg(NO3)2 in 100 mL of water, add 0.5 g citric acid, and adjust the pH to 9 to form a zinc-aluminum-magnesium sol;

[0075] S2. 3.8 g of thiourea solution was added dropwise to the sol and stirred at 70 ° C for 2 hours to obtain a ZnS precursor sol;

[0076] S3. 0.1 g of CTAB was added to the ZnS precursor sol, transferred to a hydrothermal reactor, and heated to 180°C at 2°C / min for 12 hours. After natural cooling, the mixture was washed alternately with water and ethanol to obtain a ZnS hydrothermal product.

[0077] S4. After drying the ZnS hydrothermal product, place it in a plasma treatment chamber, introduce methane, and treat it under plasma at -5°C for 10 minutes to obtain β-zinc sulfide nanoparticles.

[0078] Example 5

[0079] A method for preparing β-zinc sulfide nanoparticles is the same as that of Example 1 except that the heating rate in step S3 is 10° C. / min.

[0080] Example 6

[0081] A method for preparing β-zinc sulfide nanoparticles is the same as that of Example 1 except that the heating rate in step S3 is 1° C. / min.

[0082] Comparative Example 1

[0083] A method for preparing zinc sulfide nanoparticles is the same as Example 1 except that step S3 is replaced by adding 0.1 g of CTAB to the ZnS precursor sol, followed by calcination at 1000°C.

[0084] Comparative Example 2

[0085] A method for preparing zinc sulfide nanoparticles is the same as that of Example 1 except that a magnesium source is not included in step S1.

[0086] Comparative Example 3

[0087] A method for preparing zinc sulfide nanoparticles is the same as that of Example 1 except that an aluminum source is not included in step S1.

[0088] Comparative Example 4

[0089] A method for preparing zinc sulfide nanoparticles is the same as that of Example 1 except that step S1 contains neither a magnesium source nor an aluminum source.

[0090] Testing and Evaluation

[0091] The whiteness (referring to GB / T 5950-2008), ultraviolet absorption rate (referring to GB / T 9721-2006), specific surface area (referring to GB / T 19587-2017) and grain size (referring to GB / T 23413-2009) of the zinc sulfide nanoparticles obtained in each embodiment and comparative example were tested using instruments. The results are shown in Table 1.

[0092] Table 1 Test results

[0093]

[0094]

[0095] As can be seen from Table 1, the present application solves the performance contradiction between whiteness and ultraviolet absorption rate of zinc sulfide for glass fiber reinforced polyester engineering plastics through a sol-hydrothermal collaborative process, combined with element doping and morphology control, and achieves the synergistic optimization of high whiteness (≥95%) and high ultraviolet absorption rate (≥99%) of zinc sulfide.

Claims

1. A method for preparing β-zinc sulfide nanoparticles, characterized in that: The following steps are involved: S1. The zinc salt, dopant and complexing agent are dispersed in water and the pH is adjusted to 8-10 to obtain a zinc complex sol; S2. A sulfur source solution is added to the zinc complex sol, and a heating reaction is performed to obtain a ZnS precursor sol; S3. A template is added to the ZnS precursor sol, and the reaction is heated twice, and after washing, a ZnS hydrothermal product is obtained; S4. The ZnS hydrothermal product is treated with plasma to obtain the β-zinc sulfide nanoparticles; The dopant includes one or more of aluminum salts and magnesium salts; the template includes one or more of CTAB and P123; the complexing agent includes one or more of citric acid and EDTA; and the plasma treatment step comprises: plasma-treating the ZnS hydrothermal product at -5 to 5° C. for 10 to 30 minutes in a carbon and / or fluorine-containing atmosphere.

2. The method for preparing β-zinc sulfide nanoparticles according to claim 1, wherein The molar amount of the dopant is 1-3% of the zinc salt.

3. The method for preparing β-zinc sulfide nanoparticles according to claim 1, wherein The temperature of the primary heating reaction is 50-80°C.

4. The method for preparing β-zinc sulfide nanoparticles according to claim 1, wherein The final temperature of the secondary heating is 150-300° C., and the heating rate of the secondary heating is 2-5° C. / min.

5. The method for preparing β-zinc sulfide nanoparticles according to claim 1, wherein The washing process is as follows: washing with ethanol and water alternately.

6. The method for preparing β-zinc sulfide nanoparticles according to claim 1, wherein The zinc salt includes one or more of Zn(NO3)2 and ZnSO4; the sulfur source includes one or more of thiourea and Na2S.

7. β-zinc sulfide nanoparticles obtained by the preparation method according to any one of claims 1 to 6.

8. A glass fiber reinforced polyester engineering plastic masterbatch comprising the β-zinc sulfide nanoparticles according to claim 7.

9. The glass fiber reinforced polyester engineering plastic masterbatch according to claim 8, characterized in that: The added amount of the β-zinc sulfide nanoparticles is 0.5-2 wt % of the glass fiber reinforced polyester engineering plastic masterbatch.

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