Composite wave-absorbing material with ultraviolet shielding function and preparation method thereof

Abstract

The invention discloses a composite wave-absorbing material with an ultraviolet shielding function and a preparation method thereof.The preparation method of the composite material comprises the following steps that S1, a zinc source, a titanium source and urea react in water, and after the reaction, zinc-titanium bimetal hydroxide Zn / Ti-LDH is obtained through cooling, centrifuging, washing and drying; s2, the Zn / Ti-LDH in the S1 is dispersed in N, N-dimethylformamide, then a cerium source, an iron source and 2-aminoterephthalic acid are added, cooling, centrifuging, washing and drying are carried out after a reaction, and a bimetallic-organic framework compound Zn / Ti-LDH-Ce / Fe-MOF is obtained; and S3, dispersing the Zn / Ti-LDH (at) Ce / Fe-MOF and sodium dodecyl benzene sulfonate in water, and adding pyrrole and ammonium persulfate for reaction to prepare the composite wave-absorbing material with the ultraviolet shielding function. The composite material disclosed by the invention is good in dispersity in a high polymer material and stable in performance, and has ultraviolet shielding and wave absorbing properties.

Description

Technical Field

[0001] The invention relates to the technical field of wave-absorbing materials, and in particular to a composite wave-absorbing material with ultraviolet shielding function and a preparation method thereof. Background Art

[0002] Ultraviolet rays are a group of higher-energy spectra in sunlight. If exposed to ultraviolet radiation for a long time, not only will organisms be greatly harmed, but many polymer materials will also fade and age, and thus lose their usability.

[0003] In addition, while electronic communication technology brings convenience to humans, it also brings serious electromagnetic pollution. High-performance microwave absorbing materials can effectively shield incident electromagnetic waves through dielectric loss, magnetic loss and multiple scattering.

[0004] Therefore, functional materials with microwave / UV shielding properties have high practical application value, especially coating materials used outdoors and at high altitudes. Currently, there is little research on functional additives with such comprehensive properties. Summary of the invention

[0005] Based on the technical problems existing in the background technology, the present invention proposes a composite absorbing material with ultraviolet shielding function and a preparation method thereof. The composite material has good dispersibility in polymer materials, stable performance, and has ultraviolet shielding and absorbing properties.

[0006] The method for preparing the composite absorbing material with ultraviolet shielding function proposed by the present invention comprises the following steps:

[0007] S1: reacting a zinc source, a titanium source and urea in water, cooling, centrifuging, washing and drying after the reaction to obtain zinc-titanium double metal hydroxide Zn / Ti-LDH;

[0008] S2: Disperse the Zn / Ti-LDH in S1 in N,N-dimethylformamide, add cerium source, iron source and 2-aminoterephthalic acid, and after the reaction, cool, centrifuge, wash and dry to obtain the bimetallic-organic framework composite Zn / Ti-LDH@Ce / Fe-MOF;

[0009] S3: Disperse Zn / Ti-LDH@Ce / Fe-MOF and sodium dodecylbenzene sulfonate in water, and add pyrrole and ammonium persulfate to react to obtain a composite absorbing material with ultraviolet shielding function.

[0010] Preferably, the zinc salt in S1 is one or more of zinc nitrate, zinc chloride, zinc sulfate, and zinc acetate; and the titanium source is one or more of titanium tetrachloride, titanium nitrate, and titanium sulfate.

[0011] Preferably, the molar ratio of the zinc source, the titanium source and the urea in S1 is 1:0.4-0.6:10-15.

[0012] Preferably, the reaction temperature in S1 is 100-120°C and the reaction time is 20-28h.

[0013] Preferably, the cerium source in S2 is one or more of cerium nitrate and its hydrate, cerium chloride and its hydrate, cerium sulfate and its hydrate; the iron source is one or more of ferric nitrate, ferric chloride, and ferric sulfate.

[0014] Preferably, the mass molar ratio of Zn / Ti-LDH, cerium source, iron source and 2-aminoterephthalic acid in S2 is 1 g: 0.8-1.2 mmol: 8-10 mmol: 4-6 mmol.

[0015] Preferably, the reaction temperature in S2 is 140-160° C. and the reaction time is 16-24 h.

[0016] Preferably, the mass volume ratio of Zn / Ti-LDH@Ce / Fe-MOF, sodium dodecylbenzenesulfonate, pyrrole and ammonium persulfate in S3 is 1 g: 0.8-1.2 g: 6-8 mL: 0.5-0.7 g.

[0017] Preferably, the reaction conditions in S3 are to react at room temperature for 10-14 h.

[0018] The composite wave-absorbing material with ultraviolet shielding function prepared by the method proposed by the present invention.

[0019] Beneficial technical effects of the present invention:

[0020] (1) The composite material prepared by the present invention has both ultraviolet shielding and wave absorbing properties, and the composite material has good dispersibility in polymer materials and stable performance.

[0021] (2) The preparation method of the composite material of the present invention is simple, does not require high temperature and high pressure, has strong operability, and has a wide source of raw materials that are cheap and easy to obtain.

[0022] (3) The porous structure of Ce / Fe-MOF in the composite material of the present invention is conducive to interface polarization and provides more paths for the incidence of electromagnetic waves, thereby increasing the contact probability between electromagnetic waves and the absorber, so that the electromagnetic waves are absorbed and reflected multiple times in the pores, and the energy is converted into heat to a greater extent and dissipated; on the other hand, MOF can be used to optimize the dielectric properties of the material on the basis of adjusting the material structure, and ZnTi-LDH is conducive to achieving impedance matching, thereby achieving excellent absorbing performance of the composite material; ZnTi-LDH and Ce / Fe-MOF in the composite material of the present invention have a synergistic promoting effect on ultraviolet shielding. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The XRD spectra of the products of Examples 1, 2 and 5 of the present invention are as follows;

[0024] Figure 2 This is the XPS graph of the composite absorbing material S5 proposed in the present invention;

[0025] Figure 3 This is a SEM image of the composite absorbing material S5 proposed in the present invention;

[0026] Figure 4 The ultraviolet absorption spectra of the products of Examples 1-6 of the present invention are shown;

[0027] Figure 5 The ultraviolet transmission spectra of the PVA film, 1% S1 / PVA and S5 / PVA composite films with different contents proposed by the present invention;

[0028] Figure 6 The attenuation constant of the product S1 of Example 1 of the present invention with a filling ratio of 30wt% varies with frequency;

[0029] Figure 7 The attenuation constant of the product S2 of Example 2 of the present invention with a filling ratio of 30wt% varies with frequency;

[0030] Figure 8 The attenuation constant of the product S3 of Example 3 of the present invention with a filling ratio of 30wt% varies with frequency;

[0031] Fig. 9 The attenuation constant of the product S5 of Example 5 of the present invention with a filling ratio of 30wt% varies with frequency;

[0032] Fig.10 This is the attenuation constant variation curve of the product S6 of Example 6 of the present invention with a filling ratio of 30wt%. DETAILED DESCRIPTION

[0033] The present invention will be further explained below in conjunction with specific embodiments.

[0034] Example 1

[0035] 1.41 g ZnCl2, 0.6 mL TiCl4 and 7.5 g urea were dissolved in 50 mL distilled water, stirred to dissolve and mixed evenly, transferred to an autoclave, reacted at 110 °C for 24 h, centrifuged, the solid was washed with water several times, and dried at 80 °C for 4 h to obtain Zn / Ti-LDH (denoted as S1).

[0036] Example 2

[0037] 0.5 g Zn / Ti-LDH (S1) was added to 40 mL DMF and ultrasonically mixed. Then 0.22 g Ce(NO3)3·6H2O, 0.73 g FeCl3 and 0.45 g NH2-BDC were added, stirred to dissolve and mixed evenly, transferred to a high-pressure reactor, reacted at 150 °C for 20 h, cooled to room temperature, centrifuged, washed with DMF and ethanol respectively, and dried to obtain Zn / Ti-LDH@Ce / Fe-MOF (denoted as S2).

[0038] Example 3

[0039] 0.22 g Ce(NO3)3·6H2O, 0.73 g FeCl3 and 0.45 g NH2-BDC were stirred to dissolve and mixed evenly, transferred to a high-pressure reactor, reacted at 150°C for 20 h, cooled to room temperature, centrifuged, washed with DMF and ethanol respectively, and dried to obtain Ce / Fe-MOF (denoted as S3).

[0040] Example 4

[0041] 0.3 g Zn / Ti-LDH@Ce / Fe-MOF powder (S2), 0.3 g sodium dodecylbenzene sulfonate (SDBS) and 100 mL water were mixed and uniformly dispersed by ultrasonic dispersion. The mixture was placed in an ice bath, 1.5 mL pyrrole was added to the above solution, and stirring was continued for 60 min.

[0042] Under stirring conditions at room temperature, 0.52 mL of pyrrole and 1.7 g of APS were added to the above solution in batches, and the solution was stirred and reacted for 12 h. The solution was centrifuged, washed with water and ethanol respectively, and dried at 60 °C for 24 h to obtain the product Zn / Ti-LDH@Ce / Fe-MOF@PPy1 (denoted as S4).

[0043] Example 5

[0044] 0.3 g Zn / Ti-LDH@Ce / Fe-MOF powder (S2), 0.3 g (SDBS) and 100 mL water were mixed and uniformly dispersed by ultrasonic dispersion. The mixture was placed in an ice bath. 2.5 mL pyrrole was added to the above solution and stirring was continued for 60 min.

[0045] Under stirring conditions at room temperature, 0.52 mL of pyrrole and 1.7 g of APS were added to the above solution in batches, and the solution was stirred and reacted for 12 h. The solution was centrifuged, washed with water and ethanol respectively, and dried at 60 °C for 24 h to obtain the product Zn / Ti-LDH@Ce / Fe-MOF@PPy2 (product denoted as S5).

[0046] Example 6

[0047] 0.3 g Zn / Ti-LDH@Ce / Fe-MOF powder (S2), 0.3 g (SDBS) and 100 mL deionized water were mixed and dispersed by ultrasonication until uniform. The mixture was placed in an ice bath, 3.5 mL pyrrole was added to the above solution, and stirring was continued for 60 min.

[0048] Under stirring conditions at room temperature, 0.52 mL of pyrrole and 1.7 g of APS were added to the above solution in batches, and the solution was stirred and reacted for 12 h. The solution was centrifuged, washed with deionized water and ethanol respectively, and dried at 60 °C for 24 h to obtain the product Zn / Ti-LDH@Ce / Fe-MOF@PPy3 (denoted as S6).

[0049] Example 7

[0050] Preparation of composite film (taking polyvinyl alcohol (PVA) as the substrate as an example): 0.8 g of PVA powder is slowly added to 10 mL of water under stirring conditions, and stirred to disperse evenly; the composite material is dissolved in 10 mL of water, ultrasonically dispersed evenly, added to the above PVA solution, ultrasonically and stirred to form a uniform dispersion, the dispersion is cast on a flat plate into a film, left to stand in the air to form, vacuum dried to constant weight, and peeled off to obtain a UV shielding film.

[0051] 0.8 g of PVA powder was slowly added into 20 mL of water and stirred to disperse evenly. The same method was used to prepare a PVA film without nanoparticles.

[0052] The XRD spectra of the products of Example 1, Example 2 and Example 5 are shown in Figure 1 The 2θ of S1 spectrum is 24.15°, 28.11°, 31.15°, 32.86°, 36.08°, 58.19° and 59.41°, which are consistent with the positions corresponding to the (006), (012), (100), (101), (009), (110) and (113) crystal planes of Zn / Ti-LDH, respectively. The 2θ of S2 spectrum is 10.9, 16.8, 20.6, 29.7, 49.3, 54.9°, which are consistent with the positions corresponding to the (220), (400), (333), (444), (775) and (531) crystal planes of UiO-66-NH2, respectively. From the S5 spectrum, it can be seen that the crystal structure of Zn / Ti-LDH@Ce / Fe-MOF after wrapping polypyrrole does not change, but due to the amorphous nature of pyrrole, the intensity of some characteristic peaks decreases.

[0053] Figure 2 This is the XPS analysis of the product S5 of Example 5, which confirms the presence of C, N, O, Zn, Fe, Ti and Ce elements in the sample.

[0054] Figure 3As shown in the SEM photo of product S5 in Example 5, it can be seen from the figure that S5 shows a uniform microsphere shape, and the polypyrrole coating successfully wraps the Zn / Ti-LDH@Ce / Fe-MOF.

[0055] Figure 4 The UV spectra of products S1-S6 of Examples 1-6 show that Zn / Ti-LDH helps improve the UV absorption performance of Ce / Fe-MOF, and the UV absorption performance is further enhanced after encapsulating polypyrrole.

[0056] Figure 5 The transmittance spectrum of PVA and its composite film in the wavelength range of 200-600nm. It can be seen from the figure that the transmittance of the PVA composite film with an S5 content of 1.5% in this wavelength range is less than 10%, and it has a strong UV shielding performance.

[0057] The coaxial specimens with outer diameter of 7.00mm, inner diameter of 3.04mm and thickness of about 2mm were pressed into the coaxial specimens with wax and paraffin in the mass ratio of 3:7 in a special mold. The electromagnetic parameters were tested by AV3629D vector network analyzer, and the absorbing performance was calculated. The test frequency range was 2-18GHz. Figure 6 to Figure 10 The following are curves showing the reflection loss of different products in the range of 2-18 GHz as a function of frequency. Among them, S5 exhibits the best microwave absorption capability. When the coating matching thickness is 3.0 mm, the maximum absorption intensity reaches -46.2 dB at 14.8 GHz.

Claims

1. A method for preparing a composite absorbing material with ultraviolet shielding function, characterized in that: The steps are as follows: S1: reacting a zinc source, a titanium source and urea in water, cooling, centrifuging, washing and drying after the reaction to obtain zinc-titanium double metal hydroxide Zn / Ti-LDH; S2: Disperse the Zn / Ti-LDH in S1 in N,N-dimethylformamide, add cerium source, iron source and 2-aminoterephthalic acid, and after the reaction, cool, centrifuge, wash and dry to obtain the bimetallic-organic framework composite Zn / Ti-LDH@Ce / Fe-MOF; S3: Disperse Zn / Ti-LDH@Ce / Fe-MOF and sodium dodecylbenzene sulfonate in water, and add pyrrole and ammonium persulfate to react to obtain a composite absorbing material with ultraviolet shielding function.

2. The method for preparing a composite absorbing material with ultraviolet shielding function according to claim 1, characterized in that: The zinc salt in S1 is one or more of zinc nitrate, zinc chloride, zinc sulfate, and zinc acetate; the titanium source is one or more of titanium tetrachloride, titanium nitrate, and titanium sulfate.

3. The method for preparing a composite absorbing material with ultraviolet shielding function according to claim 1, characterized in that: The molar ratio of zinc source, titanium source and urea in S1 is 1:0.4-0.6:10-15.

4. The method for preparing a composite absorbing material with ultraviolet shielding function according to claim 1, characterized in that: The reaction temperature in S1 is 100-120°C and the reaction time is 20-28h.

5. The method for preparing a composite absorbing material with ultraviolet shielding function according to claim 1, characterized in that: The cerium source in S2 is one or more of cerium nitrate and its hydrate, cerium chloride and its hydrate, cerium sulfate and its hydrate; the iron source is one or more of ferric nitrate, ferric chloride, and ferric sulfate.

6. The method for preparing a composite absorbing material with ultraviolet shielding function according to claim 1, characterized in that: The mass molar ratio of Zn / Ti-LDH, cerium source, iron source and 2-aminoterephthalic acid in S2 is 1g:0.8-1.2mmol:8-10mmol:4-6mmol.

7. The method for preparing a composite absorbing material with ultraviolet shielding function according to claim 1, characterized in that: The reaction temperature in S2 is 140-160°C and the reaction time is 16-24h.

8. The method for preparing a composite absorbing material with ultraviolet shielding function according to claim 1, characterized in that: The mass volume ratio of Zn / Ti-LDH@Ce / Fe-MOF, sodium dodecylbenzenesulfonate, pyrrole and ammonium persulfate in S3 is 1g:0.8-1.2g:6-8mL:0.5-0.7g.

9. The method for preparing a composite absorbing material with ultraviolet shielding function according to claim 1, characterized in that: The reaction conditions in S3 are to react at room temperature for 10-14 hours.

10. A composite absorbing material with ultraviolet shielding function prepared by the method according to any one of claims 1 to 9.

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