A method for preparing PDC-RESiOC ceramics by photopolymerization 3D printing

Abstract

This invention relates to a method for preparing PDC-RESiOC ceramics by photopolymerization 3D printing, belonging to the field of electromagnetic wave absorbing materials technology. The invention involves mixing tetrahydrofuran and tripropylene glycol monomethyl ether to obtain solution A. Polysulfone and 3-(methacryloxy)propyltrimethoxysilane are then dissolved in solution A, followed by acidic hydrolysis for 12–14 hours to obtain solution C. The tetrahydrofuran solvent in solution C is evaporated at 45–55°C, leaving tripropylene glycol monomethyl ether as the solvent, to obtain solution D. Trimethylolpropane triacrylate is added to solution D and mixed thoroughly. Then, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and a rare earth salt are added sequentially and mixed thoroughly to obtain a photopolymerization pre-formed solution. Based on a pre-designed ceramic structure, the photopolymerization pre-formed solution is 3D printed to obtain a 3D preform. The 3D preform is then heated to 900–1200°C under an argon atmosphere and pyrolyzed at this temperature for 2–4 hours to obtain dense PDC-RESiOC ceramics. This invention can adjust electromagnetic parameters and microwave absorption performance by controlling the content of rare earth salts.

Description

Technical Field

[0001] This invention relates to a method for preparing PDC-RESiOC ceramics by photopolymerization 3D printing, belonging to the field of electromagnetic wave absorbing materials technology. Background Technology

[0002] Polymer conversion ceramics (PDCs) are structural / functional integrated ceramic materials characterized by low density, high temperature resistance, oxidation resistance, good thermal stability, and electromagnetic properties, giving them good formability and processability during preparation and processing. Specifically, by designing PDC precursors and controlling the pyrolysis process to adjust elemental composition and crystal domain structure, multiple loss mechanisms such as multi-interface, dipole, electrical conduction loss, and magnetic loss can be established to dissipate electromagnetic wave energy.

[0003] The most common polymer conversion ceramics currently are produced by cold pressing and sintering. However, because their preparation depends on molds, their application has not been developed. 3D printing of polymer conversion ceramics, on the other hand, allows the prepared samples to be produced without the limitations of molds, which is the most significant advantage of this method. Summary of the Invention

[0004] To address the issue that existing polymer conversion ceramics (PDCs) cannot achieve better impedance matching and dissipation performance, this invention proposes a method for preparing PDC-RESiOC ceramics using photopolymerization 3D printing. This method involves using 3D printing to prepare preforms, applying PDC technology to obtain RESiOC ceramics, and adjusting electromagnetic parameters and microwave absorption performance by controlling the content of rare earth salts.

[0005] A method for preparing PDC-RESiOC ceramics by photopolymerization 3D printing, the specific steps of which are as follows:

[0006] (1) Mix tetrahydrofuran and tripropylene glycol monomethyl ether to obtain solution A, dissolve polysulfone in solution A to obtain solution B, dissolve 3-(methacryloxy)propyltrimethoxysilane in solution B, add hydrochloric acid to adjust the pH of the solution to 5.3~6.3 and acid hydrolyze for 12~14h to obtain solution C;

[0007] (2) Evaporate the tetrahydrofuran solvent in solution C at a temperature of 45~55℃, and retain the tripropylene glycol monomethyl ether solvent to obtain solution D;

[0008] (3) Add trimethylolpropane triacrylate to solution D and mix well. Then add phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide and rare earth salt in sequence and mix well to obtain a photocurable prepreg solution.

[0009] (4) Based on the pre-designed ceramic structure, the photocurable pre-formed solution is used to obtain 3D preforms by 3D printing;

[0010] (5) The 3D preform is heated to 900~1200℃ in an argon atmosphere and kept at a constant temperature for 2~4h to obtain dense PDC-RESiOC ceramic.

[0011] In step (1), the volume ratio of tetrahydrofuran to tripropylene glycol monomethyl ether is 1~1.1:1.

[0012] In step (1), the amount of polysulfone added is 0.3~0.6 wt% of solution A, and the amount of 3-(methacryloxy)propyltrimethoxysilane added is 10~15 wt% of solution A.

[0013] In step (3), the amount of trimethylolpropane triacrylate added is 5-10 wt% of solution D, the amount of phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide added is 0.1-0.4 wt% of solution D, and the amount of rare earth salt added is 1-5 wt% of solution D.

[0014] The rare earth salt in step (3) is Nd(NO3)3.

[0015] The principle of the PDC-RESiOC ceramic of this invention to improve impedance matching characteristics and conductivity loss: This invention uses photopolymerization 3D printing technology to prepare a polymer matrix, which is not affected by the mold. After calcination and debinding, the polymer is transformed into ceramic. Due to its special process, multiple reflections and scattering are generated on its surface and in its structure, thereby achieving wave absorption performance.

[0016] The beneficial effects of this invention are:

[0017] (1) This invention uses 3D printing to prepare preforms and uses PDC technology to obtain RESiOC ceramics. By controlling the content of rare earth salts and adjusting the electromagnetic parameters and microwave absorption performance, the problem that microwave absorbing materials cannot achieve better impedance matching and dissipation performance can be solved.

[0018] (2) The rare earth salt infiltration of SiOC ceramics in this invention can significantly reduce electrical conductivity and increase porosity, thereby improving impedance matching characteristics and electrical conductivity loss;

[0019] (3) The 3D network in the RESiOC ceramic prepared by the 3D printing method of this invention can provide more space for multiple reflections, scattering of microwaves and rapid loss of microwave energy; a large number of heterogeneous interfaces and defects can also enhance polarization loss.

[0020] (4) The dense PDC-RESiOC ceramic of the present invention has a natural resonance effect because its high magnetic anisotropy enhances magnetic loss. Attached Figure Description

[0021] Figure 1SEM images of the PDC-RESiOC ceramics in comparative examples and Example 1;

[0022] Figure 2 The real part of the dielectric constant of the PDC-RESiOC ceramic in Example 1;

[0023] Figure 3 The imaginary part of the dielectric constant of the PDC-RESiOC ceramic in Example 1;

[0024] Figure 4 Impedance matching of the PDC-RESiOC ceramic in Example 1. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0026] Example 1: A method for preparing PDC-RESiOC ceramics by photopolymerization 3D printing, the specific steps of which are as follows:

[0027] (1) Tetrahydrofuran (THF) and tripropylene glycol monomethyl ether (TPM) were mixed to obtain solution A. Polysulfone (PSO) was dissolved in solution A to obtain solution B. 3-(methacryloxy)propyltrimethoxysilane was dissolved in solution B. Hydrochloric acid was added to adjust the pH of the solution to 5.3, and acid hydrolysis was performed for 12 h to obtain solution C. The volume ratio of tetrahydrofuran to tripropylene glycol monomethyl ether was 1:1. The amount of polysulfone added was 0.3 wt% of solution A, and the amount of 3-(methacryloxy)propyltrimethoxysilane added was 10 wt% of solution A.

[0028] (2) Evaporate the solvent tetrahydrofuran (THF) in solution C at a temperature of 45℃, and retain the solvent tripropylene glycol monomethyl ether (TPM) to obtain solution D;

[0029] (3) Trimethylolpropane triacrylate (TMPTA) was added to solution D and mixed evenly. Then, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide and rare earth salt (Nd(NO3)3) were added in sequence and mixed evenly to obtain a photocurable pre-prepared solution. The amount of trimethylolpropane triacrylate added was 5 wt% of solution D, the amount of phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide added was 0.1 wt% of solution D, and the amount of rare earth salt (Nd(NO3)3) added was 1 wt%, 3 wt%, and 5 wt% of solution D, respectively.

[0030] (4) Based on the pre-designed ceramic structure, the photocurable pre-formed solution is used to obtain 3D preforms by 3D printing;

[0031] (5) The 3D preform was heated to 900℃ in an argon atmosphere and kept at a constant temperature for 2 hours to obtain dense PDC-RESiOC ceramic.

[0032] Comparative Example: The difference between the comparative example and Example 1 is that rare earth salts are not added in step (3);

[0033] SEM images of the PDC-RESiOC ceramic in Example 1 and the comparative example PDC-RESiOC ceramic are shown below. Figure 1 ,from Figure 1 It is known that PDC-RESiOC ceramic materials without added rare earth salts have a dense surface, but PDC-RESiOC ceramics have low impedance matching characteristics and relatively weak microwave absorption performance (e.g., Figure 2-4 Add 1% (e.g.) Figure 1 Rare earth salt PDC-RESiOC ceramics form agglomerates on their surface and grow SiC on the surface, which can improve dielectric loss and increase reflection and scattering capabilities. 1% rare earth salt (such as...) Figure 2-4 The addition of ) improves the impedance matching characteristics and microwave absorption performance of PDC-RESiOC ceramic materials, and increases the microwave loss mechanism; the addition of 3% (such as Figure 1 Rare earth salt PDC-RESiOC ceramics exhibit the formation of numerous agglomerates on their surface. Furthermore, with increasing rare earth salt content, surface SiC further grows, leading to improved dielectric properties and enhanced reflection and scattering capabilities. (3% (e.g.)) Figure 2-4 The addition of rare earth salts further improves the impedance matching characteristics and microwave absorption performance of PDC-RESiOC ceramic materials, and enhances the microwave loss mechanism; adding 5% (such as Figure 1 Rare earth salt-based PDC-RESiOC ceramics exhibit increased surface agglomeration, and with increasing rare earth salt content, surface SiC grows again and becomes more elongated and curved, facilitating electron movement and transfer. This enhances dielectric properties and further increases reflection and scattering capabilities. (5% rare earth salt, such as...) Figure 2-4 The addition of ) further improves the impedance matching characteristics and microwave absorption performance of PDC-RESiOC ceramic materials, and increases the microwave loss mechanism.

[0034] Example 2: A method for preparing PDC-RESiOC ceramics by photopolymerization 3D printing, the specific steps of which are as follows:

[0035] (1) Tetrahydrofuran (THF) and tripropylene glycol monomethyl ether (TPM) were mixed to obtain solution A. Polysulfone (PSO) was dissolved in solution A to obtain solution B. 3-(methacryloxy)propyltrimethoxysilane was dissolved in solution B. Hydrochloric acid was added to adjust the pH of the solution to 5.6 and acidic hydrolysis was performed for 13 h to obtain solution C. The volume ratio of tetrahydrofuran to tripropylene glycol monomethyl ether was 1.3:1. The amount of polysulfone added was 0.4 wt% of solution A, and the amount of 3-(methacryloxy)propyltrimethoxysilane added was 12.5 wt% of solution A.

[0036] (2) Evaporate the solvent tetrahydrofuran (THF) in solution C at 50°C, and retain the solvent tripropylene glycol monomethyl ether (TPM) to obtain solution D;

[0037] (3) Trimethylolpropane triacrylate (TMPTA) was added to solution D and mixed evenly. Then, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide and rare earth salt (Nd(NO3)3) were added in sequence and mixed evenly to obtain a photocurable pre-prepared solution. The amount of trimethylolpropane triacrylate added was 7.5 wt% of solution D, the amount of phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide added was 0.25 wt% of solution D, and the amount of rare earth salt (Nd(NO3)3) added was 2 wt% of solution D.

[0038] (4) Based on the pre-designed ceramic structure, the photocurable pre-formed solution is used to obtain 3D preforms by 3D printing;

[0039] (5) The 3D preform was heated to 1000℃ in an argon atmosphere and kept at a constant temperature for 3h to obtain dense PDC-RESiOC ceramic;

[0040] In this embodiment, the PDC-RESiOC ceramic has a large number of agglomerates on its surface, and the surface SiC further grows to form a 3D network structure, which improves its dielectric properties and increases its reflection and scattering capabilities, thereby improving the impedance matching characteristics and microwave absorption performance of the PDC-RESiOC ceramic material and increasing the microwave loss mechanism.

[0041] Example 3: A method for preparing PDC-RESiOC ceramics by photopolymerization 3D printing, the specific steps of which are as follows:

[0042] (1) Tetrahydrofuran (THF) and tripropylene glycol monomethyl ether (TPM) were mixed to obtain solution A. Polysulfone (PSO) was dissolved in solution A to obtain solution B. 3-(methacryloxy)propyltrimethoxysilane was dissolved in solution B. Hydrochloric acid was added to adjust the pH of the solution to 6.3, and acid hydrolysis was performed for 14 h to obtain solution C. The volume ratio of tetrahydrofuran to tripropylene glycol monomethyl ether was 1.5:1, the amount of polysulfone added was 0.6 wt% of solution A, and the amount of 3-(methacryloxy)propyltrimethoxysilane added was 15 wt% of solution A.

[0043] (2) Evaporate the solvent tetrahydrofuran (THF) in solution C at a temperature of 55℃, and retain the solvent tripropylene glycol monomethyl ether (TPM) to obtain solution D;

[0044] (3) Trimethylolpropane triacrylate (TMPTA) was added to solution D and mixed evenly. Then, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide and rare earth salt (Nd(NO3)3) were added in sequence and mixed evenly to obtain a photocurable pre-prepared solution. The amount of trimethylolpropane triacrylate added was 10 wt% of solution D, the amount of phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide added was 0.4 wt% of solution D, and the amount of rare earth salt (Nd(NO3)3) added was 4 wt% of solution D.

[0045] (4) Based on the pre-designed ceramic structure, the photocurable pre-formed solution is used to obtain 3D preforms by 3D printing;

[0046] (5) The 3D preform was heated to 1100℃ in an argon atmosphere and kept at a constant temperature for 4 hours to obtain dense PDC-RESiOC ceramic;

[0047] In this embodiment, the PDC-RESiOC ceramic has a large number of agglomerates on its surface, and the surface SiC grows and becomes curved and elongated, which is conducive to electron movement and transfer, thereby improving its dielectric properties and increasing its reflection and scattering capabilities. This enhances the impedance matching characteristics and microwave absorption performance of the PDC-RESiOC ceramic material, and increases the microwave loss mechanism.

[0048] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for preparing PDC-RESiOC ceramics by photopolymerization 3D printing, characterized in that, The specific steps are as follows: (1) Mix tetrahydrofuran and tripropylene glycol monomethyl ether to obtain solution A, dissolve polysulfone in solution A to obtain solution B, dissolve 3-(methacryloxy)propyltrimethoxysilane in solution B, add hydrochloric acid to adjust the pH of the solution to 5.3~6.3 and acid hydrolyze for 12~14h to obtain solution C; (2) Evaporate the tetrahydrofuran solvent in solution C at a temperature of 45~55℃, and retain the tripropylene glycol monomethyl ether solvent to obtain solution D; (3) Add trimethylolpropane triacrylate to solution D and mix well. Then add phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide and rare earth salt in sequence and mix well to obtain a photocurable pre-prepared solution. The amount of trimethylolpropane triacrylate added is 5-10 wt% of solution D, the amount of phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide added is 0.1-0.4 wt% of solution D, and the amount of rare earth salt added is 1-5 wt% of solution D. (4) Based on the pre-designed ceramic structure, the photocurable pre-formed solution is used to obtain 3D preforms by 3D printing; (5) The 3D preform is heated to 900~1200℃ in an argon atmosphere and kept at a constant temperature for 2~4h to obtain dense PDC-RESiOC ceramic.

2. The method for preparing PDC-RESiOC ceramics by photopolymerization 3D printing according to claim 1, characterized in that: In step (1), the volume ratio of tetrahydrofuran to tripropylene glycol monomethyl ether is 1~1.5:

1.

3. The method for preparing PDC-RESiOC ceramics by photopolymerization 3D printing according to claim 1, characterized in that: In step (1), the amount of polysulfone added is 0.3~0.6 wt% of solution A, and the amount of 3-(methacryloxy)propyltrimethoxysilane added is 10~15 wt% of solution A.

4. The method for preparing PDC-RESiOC ceramics by photopolymerization 3D printing according to claim 1, characterized in that: Step (3) The rare earth salt is Nd(NO3)3.

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