A modified rare earth glaze for ceramics and preparation method thereof

Abstract

The present invention provides a modified rare earth glaze for ceramics, which is made of the following components in parts by weight: 15-20 parts of quartz, 30-50 parts of potassium feldspar, 10-15 parts of kaolin, 10-15 parts of quicklime, 1-2 parts of dispersant, and 3-5 parts of modified rare earth material. The modified rare earth glaze for ceramics of the present invention has an antibacterial performance of 92.18% against Streptococcus mutans.

Description

Technical Field

[0001] The invention belongs to the field of ceramic glazes, and in particular relates to a modified rare earth glaze for ceramics and a preparation method thereof. Background Art

[0002] The oral microbiome is composed of approximately 700 bacterial species and dental caries is a multifactorial disease that affects 60–90% of children and most adults. Biofilms are highly dynamic and structured communities of microbial cells that are firmly attached to surfaces and embedded in a self-generated extracellular matrix. Microbial colonization of tooth surfaces and the formation of cariogenic biofilms are key causes of dental caries. Bacterial interactions in biofilms are essential for the development of multispecies microbial communities and for the transition of the oral cavity from a healthy to a diseased state. Streptococcus mutans ( S. mutans ) have the abilities of adhesion, acid production, acid resistance and biofilm formation, and play a vital role in the development of dental caries. The variability of oral bacteria between different individuals is relatively low. In contrast, the complexity of individual oral microbiota is the highest compared with other parts of the body. Oral microorganisms participate in extensive cell-cell interactions. Early colonizers adhere to accessible host surfaces and promote the colonization of subsequent species through intergeneric co-aggregation, forming a highly structured polymicrobial oral biofilm. In addition, intergeneric cell-cell communication can trigger signaling cascades, induce changes in gene expression of attached species, and affect the expression of virulence factors of oral microorganisms.

[0003] Rare earth ceramic glaze is a ceramic material with antibacterial function prepared by a specific process method using the antibacterial properties of rare earth elements. Rare earth elements have strong biological activity and can interact with biological macromolecules such as bacterial cell walls, cell membranes and intracellular enzymes to destroy the normal physiological functions of bacteria, thereby achieving the purpose of antibacterial. Studies have shown that rare earth elements can exert antibacterial effects by affecting the metabolic pathways of bacteria, inhibiting the growth and reproduction of bacteria, and destroying the cell structure of bacteria. In addition, rare earth elements also have multiple biological activities such as antioxidant, anti-inflammatory, and anti-tumor, making them an ideal antibacterial material. This material has broad application prospects in the fields of medical care, environmental protection, and food packaging. Streptococcus mutans is a common oral pathogen that is closely related to the formation of dental caries. Therefore, the development of rare earth antibacterial ceramic products with antibacterial effects on Streptococcus mutans is of great significance for the prevention and treatment of dental caries. Summary of the invention

[0004] In view of this, the present invention aims to overcome the defects in the prior art and proposes a modified rare earth glaze for ceramics and a preparation method thereof.

[0005] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0006] The present invention provides a modified rare earth glaze for ceramics, which is made of the following components in parts by weight:

[0007] 15-20 parts of quartz, 30-50 parts of potassium feldspar, 10-15 parts of kaolin, 10-15 parts of quicklime, 1-2 parts of dispersant, 3-5 parts of modified rare earth material;

[0008] The modified rare earth material is prepared by a method comprising the following steps:

[0009] Step 1 is to add Cu(NO3)2 to acetic acid, stir at room temperature, add polyvinyl alcohol and DMSO thereto, mix evenly with ultrasound, reflux, and freeze-dry to obtain a copper-containing precursor;

[0010] Step 2 is to add the copper-containing precursor into deionized water, adjust the pH value of the solution, then add rare earth europium salt and nano-lanthanum cerium oxide thereto, react under stirring at room temperature, and after the reaction is completed, obtain the modified rare earth material after filtration, drying and calcination.

[0011] Furthermore, the mass ratio of Cu(NO3)2, acetic acid, polyvinyl alcohol and DMSO in step 1 is 1:2-3:0.1-0.3:1-3.

[0012] Furthermore, the stirring step in step 1 lasts for 5-15 minutes; the ultrasonic step in step 1 lasts for 5-15 minutes; the reflux step in step 1 lasts for 6-8 hours at a temperature of 100-120°C.

[0013] Furthermore, the solid-liquid ratio of the copper-containing precursor to deionized water in step 2 is 1:15-20; the mass ratio of the copper-containing precursor, rare earth europium salt and nano-lanthanum cerium oxide in step 2 is 1:0.2-0.3:1-1.5; the rare earth europium salt is Eu(NO3)3•5H2O.

[0014] Furthermore, the pH value of the solution pH adjustment step in step 2 is 9-10; the reaction step in step 2 lasts for 3-4 hours; the drying step in step 2 is at a temperature of 80-110°C; the calcination step in step 2 is at a temperature of 600-700°C and lasts for 3-4 hours.

[0015] Furthermore, the nano-lanthanum cerium oxide in step 2 is prepared by a method comprising the following steps: adding lanthanum halide and cerium salt to deionized water, slowly dropping DIEA therein under stirring, then adding trimethylammonium bromide therein, performing microwave treatment, collecting the precipitate by centrifugation after the treatment, and drying and grinding the obtained precipitate to obtain nano-lanthanum cerium oxide.

[0016] Furthermore, the solid-to-liquid ratio of the lanthanum halide, cerium salt, deionized water, DIEA and trimethylammonium bromide is 1:1-1.5:30-40:7-10:2-3.

[0017] Furthermore, the lanthanum halide is LaCl3; and the cerium salt is CePO4.

[0018] Furthermore, the stirring step has a speed of 300-500 rpm; the microwave treatment has a temperature of 100-110° C. and a time of 1-2 hours.

[0019] Furthermore, the speed of the centrifugation step is 8000-10000 rpm / 10-15 min; the temperature of the drying step is 40-50°C.

[0020] In the process of preparing nano-lanthanum cerium oxide, microwave reaction can provide fast and uniform heat energy, fully provide the activation energy required for the reaction, provide a suitable reaction environment for synthesizing nanoparticles, accelerate the reaction process, and improve the synthesis efficiency. At the same time, DIEA is used as an alkaline nucleophilic reagent, which can not only adjust the pH value of the reaction environment, but also act as a catalyst to participate in the reaction and promote the reaction between lanthanum cerium ions. In addition, trimethylammonium bromide is added during the microwave heating process, which is a stabilizer and dispersant for the reaction, affecting the shape and size of the final product.

[0021] The modified rare earth material is prepared by dissociating Cu(NO3)2 in an acetic acid solution and using polyvinyl alcohol as a template. After later reaction and calcination, copper ions loaded on carbon quantum dots can be obtained. At the same time, Eu(NO3)3•5H2O and LaCe@NPs added in the second step reaction can also be loaded on the polyvinyl alcohol template through co-precipitation after mixing. Finally, the final product is formed after high-temperature calcination, thereby forming a more stable crystal structure and improving material performance.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] The modified rare earth glaze for ceramics described in the present invention has an antibacterial performance of 92.18% on Streptococcus mutans; after the introduction of the modified rare earth material, the extracellular coating of the bacteria disappears, and in the presence of the modified rare earth material, the Streptococcus mutans increases the content of long-chain unsaturated iso-fatty acids and anti-iso-fatty acids at low pH values, and downregulates genes related to fatty acid synthesis, thereby seriously affecting the survival of the bacteria. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a physical picture of the plate-coated experimental culture medium described in the experimental examples of the present invention. DETAILED DESCRIPTION

[0025] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The test reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the experimental methods, unless otherwise specified, are all conventional methods.

[0026] Copper nitrate, cerium phosphate, lanthanum chloride, and europium nitrate pentahydrate were purchased from Shandong Desheng New Materials Co., Ltd. Quartz, potassium feldspar, kaolin, quicklime, and dispersant AK-1000 were purchased from Hebei Longfengshan Furnace Material Co., Ltd. Ammonium bicarbonate, nitric acid, trimethylammonium bromide, diisopropylethylamine, and sodium hydroxide were purchased from Beijing Solaibao Technology Co., Ltd., with a purity of more than 99%. Tryptone, beef heart extract powder, sodium chloride, glucose, disodium hydrogen phosphate, culture medium TSA and 5% defibrinated sheep blood, tryptone (casein pancreatic digest), soy peptone (soy flour papain digest), sodium chloride, and agar were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. All chemicals were used without further treatment, and distilled water (ρ=18.2 MΩ•cm, 25℃) was from Millipore milli-Q water purification system. Streptococcus mutans was from Beijing Sihuan Biopharmaceutical Co., Ltd.

[0027] The present invention will be described in detail below with reference to the embodiments.

[0028] Example 1

[0029] A method for preparing a modified rare earth glaze for ceramics comprises the following steps:

[0030] (1) Preparation of Nano-Lanthanum Cerium Oxide:

[0031] LaCl3 and CePO4 were used as raw materials to synthesize nano-lanthanum cerium oxide. 10 g LaCl3 and 12 g CePO4 were weighed and dissolved in 300 mL deionized water, and then 75 mL DIEA was slowly added to the reaction solution. During the addition, the stirring speed was controlled at 400 rpm. After the addition, the reaction solution was transferred to a microwave tube, and 22 g trimethylammonium bromide was weighed and added to the microwave tube. Then, it was placed in a microwave reactor, the reaction temperature was set to 110°C, and stirring was continued for 1 hour. Then, the precipitate was collected by centrifugation (the centrifugal condition was 10000 rpm / 15 min), dried in an oven at 45°C to remove moisture, and then ground into powder to obtain nano-lanthanum cerium oxide (LaCe@NPs).

[0032] (2) Preparation of modified rare earth material LaCeEu@Cu:

[0033] First, 20 g of Cu(NO3)2 was weighed and added to 50 mL of acetic acid. After stirring at room temperature for 10 min to fully dissolve it, 3.4 g of polyvinyl alcohol and 20 mL of DMSO were added. The mixed solution was then ultrasonicated for 10 min to ensure uniform mixing. Then, it was refluxed and stirred at 110 °C for 6 h. The reaction solution was freeze-dried to obtain a copper-containing precursor. 9 g of the copper-containing precursor was weighed and added to 158 mL of deionized water. The pH value of the solution was adjusted to 9 with NaOH. Then, 2.4 g of Eu(NO3)3•5H2O and 9.4 g of LaCe@NPs were added. The mixed solution was stirred at room temperature for 3 h. After the reaction was completed, it was filtered and washed with water and ethanol three times, dried at 100 °C, and calcined at 700 °C in a muffle furnace for 3 h.

[0034] (3) Preparation of modified rare earth glaze for ceramics:

[0035] 19 parts by weight of quartz, 50 parts by weight of potassium feldspar, 12 parts by weight of kaolin, 13 parts by weight of quicklime, 2 parts by weight of dispersant AK-1000 and 4 parts by weight of rare earth material LaCeEu@Cu are added to 100 parts of deionized water and mixed evenly to obtain the modified rare earth glaze for ceramics.

[0036] Comparative Example 1

[0037] Compared with step (2) in Example 1, the only difference is that commercially available nano-lanthanum cerium oxide (Shandong Desheng New Materials Co., Ltd.) is used to synthesize LaCeEu@Cu-1.

[0038] Comparative Example 2

[0039] Compared with step (2) in Example 1, the only difference is that Y(NO3)3•6H2O is used as a raw material to synthesize the modified rare earth material LaCeY@Cu.

[0040] Comparative Example 3

[0041] Compared with Example 1, the only difference is: Preparation of modified rare earth material LaCeEu@Cu: 2.4 g Eu(NO3)3•5H2O and 9.4 g LaCe@NPs were added to 158 mL deionized water, stirred at room temperature for 3 h, filtered after the reaction was completed and washed three times with water and ethanol, dried at 100°C, and calcined at 700°C in a muffle furnace for 3 h.

[0042] Experimental Example 1 Blood plate culture experiment

[0043] 1. Preparation of Streptococcus mutans culture medium

[0044] Add 10 g of tryptone, 17.5 g of beef heart extract powder, 5 g of sodium chloride, 2 g of glucose, and 2.5 g of disodium hydrogen phosphate to a 2 L measuring cylinder, adjust the pH to 7.4 (25°C), add 1 L of distilled water, sterilize in an autoclave, cool the sterilized solution until it is not hot to the touch, and pour it onto a plate.

[0045] 2. Preparation of Streptococcus mutans culture medium

[0046] A single colony of mutans Streptococcus was inoculated into a blood plate medium (TSA + 5% defibrinated sheep blood) and cultured in an anaerobic environment of 80% N2-10% CO2-10% H2 for 72-96 h to obtain a suspension of mutans Streptococcus with an optical density of 600 nm (OD 600 ) is used to evaluate the growth of Streptococcus mutans. In the present invention, OD 600 =0.4-0.6.

[0047] 3. Blood plate culture experiment

[0048] Different concentrations of rare earth material LaCeEu@Cu (0, 50, 100, 150 mg / L) were added to the suspension of Streptococcus mutans (OD 600 = 0.2) and incubated at 37°C for 3 h. Then, 0.2 mL of the diluted bacterial suspension was spread on blood agar plates and incubated at 37°C for 24 h. The survival rate of bacteria was determined by the standard plate count method, as shown in Table 1.

[0049] Table 1 Results and data

[0050]

[0051] It is clearly observed from the figure that in the presence of 50 mg / L rare earth composite material, the survival rate of Streptococcus mutans is 0. The above plate was transferred to a fume hood for antibacterial timeliness evaluation. After the plate was placed for 3 months, no bacteria grew further, which shows that the antibacterial performance of the material has a long timeliness.

[0052] The rare earth materials obtained in Example 1 and Comparative Examples 1-3 were respectively mixed with a suspension of Streptococcus mutans (OD 600 = 0.2) and incubated at 37°C for 3 h. Then, 0.2 mL of the diluted bacterial suspension was spread on blood agar plates and incubated at 37°C for 18 h. The bacterial survival rate was determined by the standard plate count method.

[0053] It is clearly observed from the figure that in the presence of 50 mg / L LaCeEu@Cu-1 and LaCeY@Cu, the bacterial survival rates of Streptococcus mutans were 7.82% and 95.44%, respectively, which are inferior to the performance of the composite material in Example 1.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A modified rare earth glaze for ceramics, characterized in that: The glaze comprises the following components in parts by weight: 15-20 parts of quartz, 30-50 parts of potassium feldspar, 10-15 parts of kaolin, 10-15 parts of quicklime, 1-2 parts of dispersant, 3-5 parts of modified rare earth material; The preparation method of the modified rare earth material comprises the following steps: Step 1 is to add Cu(NO3)2 to acetic acid, stir at room temperature, add polyvinyl alcohol and DMSO thereto, mix evenly with ultrasound, reflux, and freeze-dry to obtain a copper-containing precursor; Step 2 is to add the copper-containing precursor to deionized water, adjust the pH value of the solution, then add rare earth europium salt and nano-lanthanum cerium oxide thereto, react under stirring at room temperature, and after the reaction is completed, filter, dry and calcine to obtain the modified rare earth material; The mass ratio of Cu(NO3)2, acetic acid, polyvinyl alcohol and DMSO in step 1 is 1:2-3:0.1-0.3:1-3; The preparation method of nano-lanthanum cerium oxide in step 2 comprises the following steps: adding lanthanum halide and cerium salt to deionized water, slowly dropping DIEA therein under stirring, then adding trimethylammonium bromide therein, performing microwave treatment, collecting the precipitate by centrifugation after the treatment, drying and grinding the obtained precipitate to obtain nano-lanthanum cerium oxide; The solid-liquid ratio of the lanthanum halide, cerium salt, deionized water, DIEA and trimethylammonium bromide is 1:1-1.5:30-40:7-10:2-3.

2. The modified rare earth glaze for ceramics according to claim 1, characterized in that: The stirring step in step 1 lasts for 5-15 minutes; the ultrasonic step in step 1 lasts for 5-15 minutes; the reflux step in step 1 lasts for 6-8 hours at a temperature of 100-120°C.

3. The modified rare earth glaze for ceramics according to claim 1, characterized in that: The solid-liquid ratio of the copper-containing precursor to deionized water in step 2 is 1:15-20; the mass ratio of the copper-containing precursor, rare earth europium salt and nano-lanthanum cerium oxide in step 2 is 1:0.2-0.3:1-1.5; the rare earth europium salt is Eu(NO3)3•5H2O.

4. The modified rare earth glaze for ceramics according to claim 1, characterized in that: The pH value of the solution pH adjustment step in step 2 is 9-10; the reaction step in step 2 lasts for 3-4 hours; the drying step in step 2 is at a temperature of 80-110°C; the calcination step in step 2 is at a temperature of 600-700°C and lasts for 3-4 hours.

5. The modified rare earth glaze for ceramics according to claim 1, characterized in that: The lanthanum halide is LaCl3; the cerium salt is CePO4.

6. The modified rare earth glaze for ceramics according to claim 1, characterized in that: The stirring step has a speed of 300-500 rpm; the microwave treatment has a temperature of 100-110° C. and a time of 1-2 hours.

7. The modified rare earth glaze for ceramics according to claim 1, characterized in that: The speed of the centrifugation step is 8000-10000 rpm / 10-15 min; the temperature of the drying step is 40-50°C.

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