Method for preparing mesoporous calcium phosphate and mesoporous calcium phosphate

Abstract

The application discloses a preparation method of mesoporous calcium phosphate and the mesoporous calcium phosphate. The preparation method comprises the following steps: mixing an ammonium phosphate polymer with water to obtain a mixed solution; mixing and reacting a soluble calcium salt and a soluble phosphate salt with the mixed solution, and then separating a solid; and drying the solid to obtain the mesoporous calcium phosphate. The mesoporous calcium phosphate prepared by the preparation method has good stability and can be stored for a long time.

Description

Technical Field

[0001] This invention relates to the field of porous materials technology, specifically to a method for preparing mesoporous calcium phosphate and the mesoporous calcium phosphate itself. Background Technology

[0002] Mesoporous calcium phosphate, due to its advantages such as high porosity, large specific surface area, regular nanoporous structure, good biocompatibility, low cytotoxicity, and controllable morphology and composition, can induce synergistic effects and compatibility of different functional groups, expanding the functionality and application prospects of mesoporous materials. It has great application value in separation, biomedicine, and pollutant adsorption. In the application of mesoporous calcium phosphate materials, pore size and specific surface area are important influencing factors. Among them, hollow mesoporous calcium phosphate, with its controllable morphology, large specific surface area, and good stability, plays a more significant role in practical applications.

[0003] The synthesis mechanisms and strategies for porous calcium phosphate can be broadly classified into two categories: hydrothermal methods and methods based on the addition of pore-forming agents to prepare porous materials through material site occupancy. Although the above methods can prepare mesoporous calcium phosphate materials, they cannot produce mesoporous calcium phosphate with good stability and long-term storage capability. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the object of this invention is to provide a method for preparing mesoporous calcium phosphate and the mesoporous calcium phosphate itself. The preparation method of this application can yield mesoporous calcium phosphate with good stability and long-term storage capability.

[0005] Therefore, the present invention proposes a method for preparing mesoporous calcium phosphate. According to an embodiment of the present invention, the preparation method includes: mixing an ammonium phosphate polymer with water to obtain a mixed solution; reacting a soluble calcium salt and a soluble phosphate with the mixed solution and then separating the mixture to obtain a solid; and drying the solid to obtain mesoporous calcium phosphate.

[0006] According to the preparation method of this invention, ammonium phosphate polymers are used as template agents to form micelles in water, providing a reaction site for the reaction of calcium ions and phosphate ions, resulting in a more stable product. Furthermore, the ammonium phosphate polymers as template agents can also control the pore size and structure of calcium phosphate. Soluble calcium salts, as calcium ion supplements, can accumulate on the micelle surface, providing a relatively high concentration of calcium ions. Soluble phosphates, as phosphate ion supplements, can react with calcium ions to obtain mesoporous calcium phosphate. Therefore, the preparation method provided by this invention can obtain mesoporous calcium phosphate with good stability and long-term storage capability.

[0007] In addition, the preparation method according to the above embodiments of the present invention may have the following additional technical features:

[0008] In some embodiments of the present invention, the mass ratio of the ammonium phosphate polymer to water is 1:(25000-35000). This allows for the production of stable mesoporous calcium phosphate with a pore size of less than 100 μm.

[0009] In some embodiments of the present invention, the mass ratio of the soluble calcium salt to the soluble phosphate is (4.62-8.84):(3.67-6.36). This results in mesoporous calcium phosphate with good stability and long-term storage capability.

[0010] In some embodiments of the present invention, the molecular weight of the ammonium phosphate polymer is 1000-14000. This results in mesoporous calcium phosphate with good stability and long-term storage capability.

[0011] In some embodiments of the present invention, the method for preparing the mesoporous calcium phosphate satisfies at least one of the following conditions: the ammonium phosphate polymer includes polyvinyl ammonium phosphate; the soluble calcium salt includes at least one of calcium chloride, calcium nitrate, or calcium acetate; the soluble phosphate includes at least one of disodium hydrogen phosphate, ammonium phosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, sodium phosphate, sodium dihydrogen phosphate, potassium phosphate, potassium dihydrogen phosphate, or dipotassium hydrogen phosphate. Thus, mesoporous calcium phosphate with good stability and long-term storage capability can be obtained.

[0012] In some embodiments of the present invention, the mixing reaction time is 20-60 minutes. This results in mesoporous calcium phosphate with good stability and long-term storage capability.

[0013] In some embodiments of the present invention, the separation includes centrifugation. This yields mesoporous calcium phosphate with excellent stability and long-term storage capability.

[0014] In some embodiments of the present invention, the centrifugation speed is greater than 10,000 rpm. This results in mesoporous calcium phosphate with excellent stability and long-term storage capability.

[0015] In some embodiments of the present invention, the centrifugation time is 8-15 minutes. This results in mesoporous calcium phosphate with good stability and long-term storage capability.

[0016] In some embodiments of the present invention, the drying temperature is 60°C-70°C. This results in mesoporous calcium phosphate with excellent stability and long-term storage capability.

[0017] A second aspect of the present invention provides a mesoporous calcium phosphate, which, according to an embodiment of the present invention, is prepared by the above-described method.

[0018] According to the embodiments of the present invention, the mesoporous calcium phosphate prepared by the above method has a multi-level pore distribution, a large specific surface area, a large pore volume and high stability, which can improve the diffusion efficiency of reactant molecules in the pores and the material transfer efficiency, and can maintain a stable morphology at room temperature for a long time.

[0019] In addition, the mesoporous calcium phosphate according to the above embodiments of the present invention may also have the following additional technical features:

[0020] In some embodiments of the present invention, the pore size of the mesoporous calcium phosphate is 2nm-50nm.

[0021] In some embodiments of the present invention, the specific surface area of ​​the mesoporous calcium phosphate is 90 m². 2 / g-110m 2 / g.

[0022] In some embodiments of the present invention, the pore volume of the mesoporous calcium phosphate is 0.2 cm³. 3 / g-0.8cm 3 / g.

[0023] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0025] Figure 1 A schematic diagram of the process for preparing mesoporous calcium sulfate according to an embodiment of the present invention is shown;

[0026] Figure 2 The image shown is a scanning electron microscope (SEM) image of the mesoporous calcium phosphate prepared in Example 1 of this invention.

[0027] Figure 3 This shows a high-resolution transmission electron microscope image of the mesoporous calcium phosphate prepared in Example 1 of the present invention;

[0028] Figure 4 The nitrogen adsorption-desorption curve of the mesoporous calcium phosphate prepared in Example 1 of this invention is shown.

[0029] Figure 5 The infrared spectrum of the mesoporous calcium phosphate prepared in Example 1 of this invention is shown;

[0030] Figure 6 The solid state of mesoporous calcium phosphate prepared in Example 1 of this invention is shown.31 P nuclear magnetic resonance spectrum;

[0031] Figure 7 The X-ray diffraction pattern of the mesoporous calcium phosphate prepared in Example 1 of this invention is shown.

[0032] Figure 8 The image shows the pore size distribution of the mesoporous calcium phosphate prepared in Example 1 of this invention;

[0033] Figure 9 The small-angle X-ray diffraction pattern of mesoporous calcium phosphate obtained from vegetation in Example 1 of this invention is shown.

[0034] Figure 10 The image shown is a transmission electron microscope (TEM) image of the mesoporous calcium phosphate prepared in Example 2 of this invention.

[0035] Figure 11 This shows a high-resolution transmission electron microscope image of the mesoporous calcium phosphate prepared in Example 3 of the present invention;

[0036] Figure 12 The image shows a comparison between a high-resolution transmission electron microscope (HRTEM) image of the mesoporous calcium phosphate prepared in Example 1 of this invention immediately after synthesis and an HTEM image of the mesoporous calcium phosphate stored at room temperature for 180 days. Detailed Implementation

[0037] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0038] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0039] The synthesis mechanisms and strategies of porous calcium phosphate can be broadly classified into two categories: (1) Hydrothermal method: a method of preparing materials by dissolving and recrystallizing powder in a sealed pressure vessel using water as a solvent. The fractions obtained by the hydrothermal method have advantages such as complete particle size development, small particle size, uniform distribution, and less particle agglomeration; (2) Methods for preparing porous materials by adding pore-forming agents to occupy material sites, including organic foam impregnation method, gas foaming method, and pore-forming agent addition method. This method can prepare materials with extremely high porosity, and by controlling the type of pore-forming agent and reaction conditions, the porosity, thermodynamic properties, etc. of the porous material can be affected, and channels of different shapes can also be prepared.

[0040] Although the above methods can prepare mesoporous calcium phosphate materials, there are also many defects, such as: (1) the pore size of calcium phosphate prepared by the above methods is mostly greater than 100 μm, and mesoporous structures cannot be prepared; (2) the mesoporous calcium phosphate prepared by the above methods cannot be stored stably at room temperature for a long time; (3) when preparing mesoporous calcium phosphate by the pore-forming agent process, the raw materials are required to be more numerous and the standards are higher, and the foaming process technology is not easy to control.

[0041] Therefore, in one aspect, the present invention provides a method for preparing mesoporous calcium phosphate, aiming to obtain mesoporous calcium phosphate with good stability and long-term storage capability. According to embodiments of the present invention, such as... Figure 1 As shown, the method includes:

[0042] S100: Mix ammonium phosphate polymers with water

[0043] It should be noted that mesoporous calcium phosphate is a type of mesoporous material. Typically, the pore size of mesoporous materials is 2nm-50nm, for example, 5nm-45nm, 10nm-40nm, 15nm-35nm, 20nm-30nm, etc. Therefore, mesoporous materials have the characteristics of high specific surface area, regular and ordered pore structure, and continuously adjustable pore size, which makes them of great application value in separation, biomedicine, and adsorption of pollutants.

[0044] In the embodiments of this application, ammonium phosphate polymers are used as template agents. They are mixed and stirred with water at room temperature, and after the solution becomes clear, a mixed solution of ammonium phosphate polymers is obtained. It should be noted that ammonium phosphate polymers refer to a class of polymers containing ammonium phosphate groups.

[0045] According to some embodiments of the present invention, the mass ratio of the ammonium phosphate polymer to water is 1:(25000-35000), for example, the mass ratio of the ammonium phosphate polymer to water can be 1:(26000-34000), 1:(27000-33000), 1:(28000-32000), 1:(29000-31000), etc. The ammonium phosphate polymer, as a template agent, can regulate the pore size and structure of nanomaterials. When the content of the ammonium phosphate polymer is too high, the synthesized mesoporous calcium phosphate will have a large pore size; when the content of the ammonium phosphate polymer is too low, the prepared mesoporous calcium phosphate will have a small pore size. Therefore, limiting the mass ratio of the ammonium phosphate polymer to water within the above range can help maintain the pore size of the mesoporous calcium phosphate within the mesoporous range.

[0046] According to some embodiments of the present invention, in order to prepare mesoporous calcium phosphate with a more regular mesoporous structure, the molecular weight of the ammonium phosphate polymer is 1000-14000. For example, the molecular weight of the ammonium phosphate polymer can be 2000-11000, 5000-9000, 6000-7000, etc. When the molecular weight of the ammonium phosphate polymer is too large, it will result in the mesoporous calcium phosphate having an excessively large pore size, irregular morphology, and easy agglomeration; when the molecular weight of the ammonium phosphate polymer is too small, it will result in the mesoporous calcium phosphate having an excessively small pore size. Therefore, controlling the molecular weight of the ammonium phosphate polymer can make the product have a more regular mesoporous structure and a better morphology, forming a porous spherical sample with a thick-shell structure.

[0047] According to some embodiments of the present invention, the ammonium phosphate polymer includes polyvinyl ammonium phosphate. Polyvinyl ammonium phosphate is a white polymer compound that is commonly used as an environmentally friendly reagent. However, in this application, polyvinyl ammonium phosphate is used as a template agent, which can form micelles in water, allowing soluble calcium salts to accumulate on the surface of the micelles, providing a relatively high concentration of calcium ions and promoting the reaction.

[0048] S100: After reacting the soluble calcium salt and soluble phosphate with the mixed solution, separate...

[0049] In the embodiments of this application, soluble calcium salt and soluble phosphate are added sequentially to a mixed solution of ammonium phosphate polymers, and the mixture is reacted at room temperature to obtain a mixed product. The mixed product is then separated to obtain a solid product. It should be noted that the order of addition of soluble calcium salt and soluble phosphate is not particularly limited, and those skilled in the art can choose according to their needs.

[0050] According to some embodiments of the present invention, the mass ratio of the soluble calcium salt to the soluble phosphate is (4.62-8.84):(3.67-6.36), for example, the mass ratio of the soluble calcium salt to the soluble phosphate can be (5-8.5):(4-6.3), (5.5-8):(4.5-6), (6-7):(5-6), etc. In the embodiments of this application, the soluble calcium salt dissolves in water to release calcium ions, and the soluble phosphate dissolves in water to release phosphate ions. Calcium phosphate is obtained by the combination of calcium ions and phosphate ions. During the reaction, when the content of soluble calcium salt is high, the pore size of the mesoporous calcium phosphate will be irregular; when the content of soluble calcium salt is low, the mesoporous calcium phosphate will easily agglomerate and become unstable during the synthesis process. Therefore, limiting the mass ratio of soluble calcium salt to soluble phosphate within the above range can keep the morphology of the mesoporous calcium phosphate relatively stable.

[0051] According to some embodiments of the present invention, the soluble calcium salt includes at least one of calcium chloride, calcium nitrate, or calcium acetate. The selected soluble calcium salts are capable of generating calcium ions in water, promoting the reaction. Thus, mesoporous calcium phosphate with good stability and long-term storage capability can be obtained.

[0052] According to some embodiments of the present invention, the soluble phosphate includes at least one selected from disodium hydrogen phosphate, ammonium phosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, sodium phosphate, sodium dihydrogen phosphate, potassium phosphate, potassium dihydrogen phosphate, or dipotassium hydrogen phosphate. The selected soluble phosphates can generate phosphate ions in water, which can promote the reaction. Therefore, mesoporous calcium phosphate with good stability and long-term storage capability can be obtained.

[0053] According to some embodiments of the present invention, the mixing reaction time is 20-60 minutes, for example, 23-57 minutes, 25-45 minutes, 38-40 minutes, etc. If the reaction time is too short, the reaction will be incomplete, resulting in irregular morphology of the mesoporous calcium phosphate. If the reaction time is too long, the mesoporous calcium phosphate will agglomerate. Therefore, limiting the reaction time within the above range will result in a uniform and dispersed morphology of the mesoporous calcium phosphate.

[0054] According to some embodiments of the present invention, the separation method is not particularly limited, and those skilled in the art can choose it as needed. In a specific embodiment of this application, centrifuge is selected for separation, which can improve product yield while simplifying the operation method.

[0055] According to some embodiments of the present invention, the centrifugal separation speed is greater than 10,000 rpm. For example, the centrifugal separation speed can be 11,000 rpm, 12,000 rpm, 13,000 rpm, 14,000 rpm, etc. When the speed is too low, the solid precipitation of mesoporous calcium phosphate is too small, resulting in a low yield of mesoporous calcium phosphate and waste. Therefore, limiting the centrifugal separation speed within the above range can increase the yield of mesoporous calcium phosphate.

[0056] According to some embodiments of the present invention, the centrifugation time is 8-15 minutes. For example, the centrifugation time can be 9-14 minutes, 10-13 minutes, 11-12 minutes, etc. If the centrifugation time is too short, the solid precipitation of mesoporous calcium phosphate will be incomplete; if the centrifugation time is too long, impurities will precipitate in the target product, resulting in a decrease in the purity of the mesoporous calcium phosphate. Therefore, limiting the centrifugation time to the above range allows for the acquisition of mesoporous calcium phosphate with better purity while also increasing the yield of mesoporous calcium phosphate.

[0057] S100: Dry the solid

[0058] In this step, the solid product obtained by centrifugation is placed in an oven for drying, and finally mesoporous calcium phosphate is obtained.

[0059] According to some embodiments of the present invention, the drying temperature is 60℃-70℃. For example, the drying temperature can be 61℃-69℃, 62℃-68℃, 63℃-66℃, etc. When the drying temperature is too high, it will cause the mesoporous calcium phosphate to agglomerate; when the drying temperature is too low, it will cause the drying time to be too long. Therefore, by limiting the drying temperature within the above range, uniformly dispersed mesoporous calcium phosphate can be obtained.

[0060] According to embodiments of the present invention, ammonium phosphate polymers are used as template agents to form micelles in water, providing a site for the reaction of calcium ions and phosphate ions, resulting in a more stable product. Furthermore, ammonium phosphate polymers as template agents can also control the pore size and structure of nanomaterials. Soluble calcium salts, as calcium ion supplements, can enrich the micelle surface, providing a relatively high concentration of calcium ions. Soluble phosphates, as phosphate ion supplements, can react with calcium ions to obtain mesoporous calcium phosphate. Therefore, the preparation method provided by the present invention uses mild reaction conditions, environmentally friendly raw materials, recyclable waste liquid, simple equipment, high repeatability, short processing time, and high efficiency. This method can produce mesoporous calcium phosphate with excellent stability and long-term storage capability.

[0061] A second aspect of the present invention provides a mesoporous calcium phosphate, which, according to an embodiment of the present invention, is prepared by the above-described method.

[0062] According to embodiments of the present invention, the mesoporous calcium phosphate prepared by the above method has a multi-level pore distribution, a large specific surface area, a large pore volume and high stability, which can improve the diffusion efficiency of reactant molecules in the pores and the material transfer efficiency, and can maintain a stable morphology at room temperature for a long time.

[0063] According to some embodiments of the present invention, see [reference]. Figure 7 The XRD pattern of this mesoporous calcium phosphate shows that it has an amorphous structure. Amorphous mesoporous calcium phosphate exhibits excellent osteoconductivity and cell adhesion, a high biodegradation rate, and the released calcium and phosphate ions promote mineralization. Furthermore, due to its unstable amorphous state, it tends to directly transform into a hard tissue morphology under the influence of the in vivo environment. Therefore, the mesoporous calcium phosphate obtained in this application is suitable for biomedical applications.

[0064] According to some embodiments of the present invention, the pore size of the mesoporous calcium phosphate is 2nm-50nm. For example, the pore size of the mesoporous calcium phosphate can be 5nm-40nm, 11nm-30nm, 15nm-35nm, 20nm-30nm, etc. Therefore, the calcium phosphate prepared by the method of this application is a mesoporous material.

[0065] According to some embodiments of the present invention, the specific surface area of ​​the mesoporous calcium phosphate is 90 m². 2 / g-110m 2 / g, for example, the specific surface area of ​​mesoporous calcium phosphate can be 91m². 2 / g-100m 2 / g, 92m 2 / g-98m 2 / g, 93m 2 / g-97m 2 / g, 94m 2 / g-96m 2 / g, etc. Therefore, the mesoporous calcium phosphate prepared by the method of this application has a large specific surface area.

[0066] According to some embodiments of the present invention, the mesoporous calcium phosphate has a pore volume of 0.2 cm³. 3 / g-0.8cm 3 / g, for example, the pore volume of mesoporous calcium phosphate can be 0.3 cm³. 3 / g-0.7cm 3 / g, 0.4cm 3 / g-0.6cm 3 / g, 0.5cm 3 / g-0.6cm 3 / g, etc., thus, the mesoporous calcium phosphate prepared by the method of this application has a large pore volume.

[0067] The applications of mesoporous calcium phosphate are not particularly limited. For example, according to some embodiments of the present invention, the mesoporous calcium phosphate obtained by the preparation method of this application has a hierarchical pore distribution and a large specific surface area and pore volume, thus making it of great application value in separation, biomedicine, adsorption of pollutants, and catalysis. Those skilled in the art can freely choose according to their needs.

[0068] The present disclosure will be explained below with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be construed as limiting the scope of the disclosure. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0069] Example 1

[0070] 1) At room temperature, 0.042 g of polyvinyl alcohol ammonium phosphate was dissolved in 1200 mL of deionized water. After the solution was dissolved until clear, a mixed solution of polyvinyl alcohol ammonium phosphate was obtained.

[0071] 2) Add 0.33g of calcium chloride and 0.18g of disodium hydrogen phosphate to a mixed solution of polyvinyl alcohol and ammonium phosphate. After reacting at room temperature for 20 minutes, pour the resulting product into a centrifuge tube and centrifuge at 11,000 rpm for 15 minutes to obtain a solid product.

[0072] 3) Place the obtained solid product in an oven and dry it at 65°C for 30 min to obtain mesoporous calcium phosphate.

[0073] The mesoporous calcium phosphates obtained in Examples 2-11 are the same as those in Example 1, except for the different parameters in the preparation method (see Table 1).

[0074] The parameters of the mesoporous calcium phosphate obtained in Examples 1-11 of this application during the preparation process are shown in Table 1.

[0075] Table 1

[0076]

[0077]

[0078] Characterization tests:

[0079] Taking Example 1 as an example, nitrogen was used to conduct an adsorption-desorption experiment on mesoporous calcium phosphate at room temperature to obtain nitrogen adsorption-desorption curves. The specific surface area, pore size, and pore volume of mesoporous calcium phosphate were calculated by the BET method and the BJH method, respectively, using the adsorption-desorption curves.

[0080] Using the above method, adsorption-desorption experiments were conducted on the mesoporous calcium phosphate obtained in Examples 2-11, and the specific surface area, pore size, and pore volume of the mesoporous calcium phosphate were calculated. The results are shown in Table 2.

[0081] Table 2

[0082] <![CDATA[Specific surface area / m 2 ·g -1 > Aperture / nm <![CDATA[Pore volume / cm 3 ·g -1 > Example 1 94.94 26.87 0.48 Example 2 94.02 24.58 0.58 Example 3 93.98 22.51 0.62 Example 4 90.56 20.98 0.25 Example 5 91.02 21.03 0.33 Example 6 92.25 24.53 0.33 Example 7 94.69 24.52 0.36 Example 8 95.26 22.46 0.29 Example 9 97.21 20.01 0.21 Example 10 69.65 19.58 0.36 Example 11 89.25 21.12 0.40

[0083] As shown in the table above, comparing the test results of the mesoporous calcium phosphate obtained in Comparative Examples 1-9 and Comparative Example 1, the mesoporous calcium phosphate prepared using the method of this application has a specific surface area of ​​90 m². 2 / g-100m 2 / g, pore size 20nm-30nm, pore volume 0.2cm³ 3 / g-0.8cm 3 The result of the sample size is / g, indicating that the preparation method of this application can yield mesoporous calcium phosphate with a large specific surface area and pore volume. A comparison of the data from Examples 1 and 6-11 reveals that as the molecular weight of polyvinyl ammonium phosphate gradually increases, the pore size of the mesoporous calcium phosphate first increases and then decreases. This demonstrates that by reasonably changing the molecular weight of polyvinyl ammonium phosphate, the pore size of the mesoporous calcium phosphate can be controlled, thereby affecting its morphology and structure. A comparison of the test data for specific surface area, pore size, and pore volume of the mesoporous calcium phosphate obtained in Examples 1 and 2-11 shows that the comprehensive test results of Example 1 are optimal, indicating that the mesoporous calcium phosphate obtained in Example 1 has greater application potential.

[0084] Figure 2 The image shows a scanning electron microscope (SEM) image of the mesoporous calcium phosphate prepared in Example 1 of the present invention. As can be seen from the image, the morphology of the mesoporous calcium phosphate is a continuous aggregate of mesoporous spherical particles with a rough surface.

[0085] Figure 3 The image shows a high-resolution transmission electron microscope (TEM) image of the mesoporous calcium phosphate prepared in Example 1 of this invention. As can be seen from the image, there are many white spots on the surface of the microstructure of the mesoporous calcium phosphate material. These white spots are formed by mesopores and channels inside the material under the high-resolution TEM, which further confirms the existence of the mesoporous morphology of the mesoporous calcium phosphate and that the mesoporous structure is clearly visible.

[0086] Figure 4 The nitrogen adsorption-desorption curve of the mesoporous calcium phosphate prepared in Example 1 of this invention is shown. As can be seen from the figure, the adsorption-desorption curve of the mesoporous calcium phosphate in Example 1 of this application is consistent with the V-type adsorption isotherm defined by the International Union of Pure and Applied Chemistry (IUPAC) and belongs to the H1 type hysteresis loop, indicating its mesoporous structure characteristics.

[0087] Figure 5 The infrared spectrum of the mesoporous calcium phosphate prepared in Example 1 of the present invention is shown. It can be seen from the figure that wavenumbers 918 and 733 correspond to the rocking vibration peaks of POC and -CH2-, respectively, indicating that polyvinyl ammonium phosphate is stably present in the mesoporous calcium phosphate.

[0088] Figure 6 The solid state of mesoporous calcium phosphate prepared in Example 1 of this invention is shown. 31 The P nuclear magnetic resonance spectrum shows chemical shifts of -2.6 and -6.4, indicating that the solid contains two different chemical environments of P. -2.6 represents calcium phosphate, and -6.4 represents a compound formed by organophosphorus and calcium.

[0089] Figure 7The X-ray diffraction pattern of the mesoporous calcium phosphate prepared in Example 1 of the present invention is shown. It can be seen from the figure that a peak appears at around 2θ = 30°, which is a characteristic diffraction peak of mesoporous calcium phosphate.

[0090] Figure 8 The image shows the pore size distribution of the mesoporous calcium phosphate prepared in Example 1 of the present invention. It can be seen from the image that the average pore size of the mesoporous calcium phosphate is 26.87 nm, and the pore size of most pores is 2.18 nm, which is consistent with the characteristics of mesoporous materials.

[0091] Figure 9 The small-angle X-ray diffraction pattern of the mesoporous calcium phosphate prepared in Example 1 of the present invention is shown. It can be seen from the figure that there is a broad diffraction peak at 2θ = 0.78°, and no other obvious characteristic crystallization peaks are shown, indicating that its pores have a certain degree of order, which is basically consistent with the observation results of the sample by transmission electron microscopy.

[0092] Figure 10 The image shows a transmission electron microscope (TEM) image of the mesoporous calcium phosphate prepared in Example 2 of this invention. It can be seen from the image that the pores of the sample are small and the pore size distribution is uneven.

[0093] Figure 11 The image shows a high-resolution transmission electron microscope (TEM) image of the mesoporous calcium phosphate prepared in Example 3 of the present invention. It can be seen from the image that the sample particles are small and severely aggregated.

[0094] Stability test:

[0095] Taking Example 1 as an example, after the prepared mesoporous calcium phosphate was kept at room temperature for 180 days, the sample was characterized by scanning electron microscopy and transmission electron microscopy, and compared with the spectrum at the time of synthesis. If the morphology changed, it was recorded as "changed"; if the structure was similar to the result at the time of synthesis, it was recorded as "unchanged".

[0096] The stability of the mesoporous calcium phosphate obtained in Examples 2-11 was tested using the above method, and the results are shown in Table 3.

[0097] Table 3

[0098]

[0099]

[0100] From Table 3 and Figure 12It can be seen that the mesoporous calcium phosphate obtained in Example 1 did not change its morphology after being kept at room temperature for 180 days, and the mesoporous calcium phosphate obtained in Examples 2-11 also did not change its morphology after being kept at room temperature for 180 days. Therefore, the mesoporous calcium phosphate obtained by the preparation method of this application can be stored at room temperature for a long time, indicating that it has good room temperature stability.

[0101] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," "some implementations," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0102] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing mesoporous calcium phosphate, characterized in that, include: Ammonium phosphate polymers are mixed with water to obtain a mixed solution; After reacting the soluble calcium salt and soluble phosphate with the mixed solution, the solid is separated. The solid was dried to obtain mesoporous calcium phosphate. The mass ratio of the ammonium phosphate polymer to water is 1:(25000-35000). The molecular weight of the ammonium phosphate polymer is 1000-14000; The ammonium phosphate polymers include polyvinyl alcohol ammonium phosphate.

2. The preparation method according to claim 1, characterized in that, The mass ratio of the soluble calcium salt to the soluble phosphate is (4.62-8.84):(3.67-6.36).

3. The preparation method according to claim 1 or 2, characterized in that, The method satisfies at least one of the following conditions: The soluble calcium salt includes at least one of calcium chloride, calcium nitrate, or calcium acetate; The soluble phosphate includes at least one of disodium hydrogen phosphate, ammonium phosphate, ammonium dihydrogen phosphate, sodium hydrogen phosphate, sodium dihydrogen phosphate, potassium phosphate, potassium dihydrogen phosphate, or dipotassium hydrogen phosphate.

4. The preparation method according to claim 1 or 2, characterized in that, The mixing reaction time is 20 min-60 min.

5. The preparation method according to claim 1 or 2, characterized in that, The separation includes centrifugal separation.

6. The preparation method according to claim 5, characterized in that, The centrifugal separation speed is greater than 10,000 rpm.

7. The preparation method according to claim 5, characterized in that, The centrifugation time is 8 min-15 min.

8. The preparation method according to claim 1 or 2, characterized in that, The drying temperature is 60℃-70℃.

9. A mesoporous calcium phosphate, characterized in that, It is prepared by the method described in any one of claims 1-8.

10. The mesoporous calcium phosphate according to claim 9, characterized in that, The mesoporous calcium phosphate has a pore size of 2 nm-50 nm.

11. The mesoporous calcium phosphate according to claim 9, characterized in that, The specific surface area of ​​the mesoporous calcium phosphate is 90 m². 2 / g-110 m 2 / g.

12. The mesoporous calcium phosphate according to claim 11, characterized in that, The mesoporous calcium phosphate has a pore volume of 0.2 cm³. 3 / g-0.8 cm 3 / g.

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