Polymethyl methacrylate (PMMA) recyclable wave-absorbing buoyancy material and preparation method thereof

Abstract

The invention provides a PMMA recyclable wave-absorbing buoyancy material and a preparation method thereof, and belongs to the technical field of polymer composite materials. The preparation method comprises the following steps: adding an initiator into PMMA (polymethyl methacrylate) liquid resin with certain viscosity, then introducing hollow microspheres into the resin as a light filler and a closed pore structure unit, adding a proper amount of a wave-absorbing agent, and curing and molding in a mold through in-situ polymerization. By constructing a low-density and closed-pore type polymer composite system, electromagnetic wave absorption and buoyancy bearing functions are synergistically realized. The density of the prepared material is lower than that of water, and long-term buoyancy is achieved; through interface polarization and multiple scattering effects, stable wave-absorbing performance (RL < =-10 dB) is obtained on the premise of ensuring good impedance matching.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials technology, and in particular to a recyclable PMMA wave-absorbing buoyancy material and its preparation method. Background Technology

[0002] With the rapid development of modern electronic information technology, electromagnetic waves are increasingly widely used in communications and civilian fields, and the resulting electromagnetic interference (EMI) and electromagnetic radiation pollution problems are becoming increasingly serious. As a functional material that can effectively absorb and dissipate electromagnetic wave energy, absorbing materials play a crucial role in electromagnetic compatibility, target stealth, and electronic equipment protection.

[0003] In water-related applications such as marine monitoring, underwater communication, and offshore platforms, new requirements are being placed on functional materials. Equipment not only needs excellent electromagnetic wave absorption performance but also the ability to float on the water surface or at specific water layers for extended periods, requiring low density and high buoyancy. Traditional absorbing materials, such as ferrites and metallic magnetic powders, while exhibiting excellent absorption performance, generally have high densities (typically greater than 3 g / cm³). 3 This makes it difficult to meet the requirements of buoyancy applications. Even after combining it with a polymer matrix, the overall density of the material remains too high, requiring additional buoyancy structure support, which increases the complexity and cost of the system.

[0004] To address these issues, researchers have developed various lightweight microwave absorbing materials. For example, by introducing microwave absorbing agents (such as carbon nanotubes, graphene, and carbonyl iron powder) into lightweight porous matrices like polyurethane foam and epoxy resin foam, buoyancy materials with a certain microwave absorption capacity can be prepared. However, these materials typically suffer from the following drawbacks: First, the matrix is ​​often a thermosetting resin, which forms an irreversible network structure after cross-linking and curing. This makes it difficult to recycle and reuse the material once it is damaged or discarded, resulting in resource waste and "white pollution." Second, the open-cell foam structure easily absorbs water, causing buoyancy performance to decline over time. Furthermore, water intrusion also deteriorates the material's dielectric properties, affecting microwave absorption stability. Third, to achieve effective microwave absorption, a high content of microwave absorbing agent is often required. This not only increases the material density but may also disrupt impedance matching, leading to poor microwave absorption performance.

[0005] Therefore, developing a novel composite material that integrates low density, excellent wave-absorbing performance, long-term buoyancy stability, and green recyclability is of significant theoretical and practical value for promoting the application of wave-absorbing materials in marine and other fields. Current technologies have not yet provided a comprehensive solution that perfectly coordinates all the above-mentioned properties, especially possessing efficient and convenient recycling capabilities. Summary of the Invention

[0006] The purpose of this invention is to provide a recyclable PMMA wave-absorbing buoyancy material and its preparation method. This method aims to solve the following technical problem: how to prepare a composite material with a density lower than water, stable wave-absorbing performance, resistance to water erosion, and recyclability of both the matrix and functional filler.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing a recyclable PMMA wave-absorbing buoyancy material, comprising the following steps: 1) Polymethyl methacrylate and acrylic resin monomers are reacted under the action of a free radical initiator to obtain a PMMA liquid resin with a certain viscosity; 2) Hollow microspheres and microwave absorbing agent are added to PMMA liquid resin for dispersion treatment to obtain a suspension slurry; 3) The mixture is solidified and molded in a mold to obtain the PMMA recyclable wave-absorbing buoyancy material.

[0008] Furthermore, the acrylic resin monomer comprises methyl methacrylate and / or methacrylic acid; The mass ratio of polymethyl methacrylate to acrylic resin monomer is 5~30:70~95.

[0009] Furthermore, the free radical initiator includes a thermal initiator or a photoinitiator; The amount of the free radical initiator added is 1 to 5% of the total mass of polymethyl methacrylate and acrylic resin monomers.

[0010] Furthermore, in step 1), the reaction temperature is 30~45℃ and the reaction time is 10~20h.

[0011] Furthermore, the polymethyl methacrylate has a number-average molecular weight ≥ 80,000.

[0012] Furthermore, the hollow microspheres include one or more of hollow glass microspheres, hollow silicon carbide microspheres, hollow ceramic microspheres, hollow plastic microspheres, hollow metal microspheres, and hollow carbon microspheres, and the amount of hollow microspheres added is 5 to 30% of the total mass of the PMMA recyclable wave-absorbing buoyancy material.

[0013] Furthermore, the hollow microspheres have a closed-cell structure and a tap density of 0.1~0.6 g / cm³.

[0014] Furthermore, the absorbing agent comprises one or more of carbon-based absorbing agents, metal-based absorbing agents, and magnetic absorbing agents, and the amount of the absorbing agent added is 1 to 30% of the total mass of the PMMA recyclable absorbing buoyancy material.

[0015] Furthermore, the curing conditions are as follows: first, keep the temperature at 30~40℃ for 8~12 hours, then raise the temperature to 70~90℃ and keep it at 1~3 hours to complete the curing.

[0016] The present invention also provides a recyclable PMMA wave-absorbing buoyancy material prepared by the above preparation method.

[0017] The beneficial effects of this invention are: 1. Synergistic Functions and Adjustable Performance: This invention successfully integrates low-density buoyancy and electromagnetic wave absorption functions into a single system by constructing a PMMA / hollow microsphere / wave-absorbing agent composite system. By adjusting the types and proportions of each component, the density, mechanical properties, and wave-absorbing performance of the material can be flexibly controlled to meet the needs of different application scenarios.

[0018] 2. Low density and long-term buoyancy: By introducing a large number of low-density hollow microspheres, the overall density of the material can be controlled at 1.0 g / cm³. 3 The hollow microspheres exhibit excellent inherent buoyancy. Their closed-cell structure effectively suppresses water absorption, ensuring long-term buoyancy stability in aquatic environments.

[0019] 3. Excellent absorption performance: This invention utilizes a low content of absorbing agent, combined with the interfacial polarization and multiple scattering effects generated by the numerous heterogeneous interfaces introduced by hollow microspheres, to synergistically enhance the attenuation capability of electromagnetic waves. While ensuring good impedance matching, effective absorption can be achieved over a wide frequency band (reflection loss RL ≤ -10dB).

[0020] 4. Green and Environmentally Friendly & Recyclable: The greatest innovation of this invention lies in its recyclability. The thermoplastic PMMA used as the matrix can be effectively dissolved by its monomer MMA. This characteristic allows for the effective separation and recycling of the PMMA matrix, hollow microspheres, and absorbing agent in decommissioned microwave absorbing buoyancy materials, achieving full-component recycling of the material. This aligns with the requirements of green chemistry and sustainable development, solving the problem of the difficulty in degrading and recycling traditional thermosetting composite materials.

[0021] 5. Simple preparation process: The present invention adopts a molding process of in-situ polymerization and curing of liquid resin, which has the advantages of short process flow, low equipment requirements, can be carried out at room temperature or under mild heating conditions, and easy to realize the preparation of complex shaped components, making it suitable for large-scale production. Attached Figure Description

[0022] Figure 1 This is a model diagram of the PMMA recyclable microwave absorbing buoyancy material prepared in Example 1 of the present invention; wherein, 1 is the microwave absorbing core material, 2 is the hollow microsphere, and 3 is the microwave absorbing agent. Detailed Implementation

[0023] This invention provides a method for preparing a recyclable PMMA wave-absorbing buoyancy material, comprising the following steps: 1) Polymethyl methacrylate and acrylic resin monomers are reacted under the action of a free radical initiator to obtain a PMMA liquid resin with a certain viscosity; 2) Hollow microspheres and microwave absorbing agent are added to PMMA liquid resin for dispersion treatment to obtain a suspension slurry; 3) The mixture is solidified and molded in a mold to obtain the PMMA recyclable wave-absorbing buoyancy material.

[0024] In this invention, the acrylic resin monomer comprises methyl methacrylate and / or methacrylic acid; The mass ratio of polymethyl methacrylate to acrylic resin monomer is 5~30:70~95, preferably 10~25:75~90, and more preferably 15~20:80~85.

[0025] In this invention, the free radical initiator includes a thermal initiator or a photoinitiator; The amount of the free radical initiator added is 1-5% of the total mass of polymethyl methacrylate and acrylic resin monomers, preferably 2-4%, and more preferably 3%.

[0026] In this invention, the thermal initiator comprises azobisisobutyronitrile (AIBN), benzoyl peroxide (BPO), N,N-dimethylaniline (DMA), tert-butyl peroxyneodecanate, benzoyl peroxide, dibutyl peroxydicarbonate, tert-butyl peroxy(2-ethylhexanoate), tert-butyl peroxyacetate, tetramethylbutyl peroxyneodecanate, dodecyl peroxide, bis(4-butylcyclohexyl) peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, butyl peroxyneodecanate, dipropyl peroxydicarbonate, diisopropyl peroxydicarbonate, diethoxyethyl peroxydicarbonate, diethoxyhexyl peroxydicarbonate, hexyl peroxydicarbonate, methyl ethyl ketone peroxide, cyclohexanone peroxide, and dicarbonyl peroxide. Dimethoxybutyl ester, bis(3-methoxy-3-methoxybutyl) peroxide dicarbonate, dibutyl peroxide dicarbonate, di(hexadecyl) peroxide dicarbonate, ditetradecyl peroxide dicarbonate, cumene hydroperoxide, tert-butyl peroxide, 1,1,3,3-tetramethylbutyl peroxyneopentate, hexyl peroxyneopentate, butyl peroxyneopentate, trimethylhexanoyl peroxide, dimethylhydroxybutyl peroxyneopentate, pentyl peroxyneopentate, butyl peroxyneopentate, tert-butyl peroxyneopentate, pentyl peroxyneopentate, tert-butyl peroxyneopentate, tert-butyl peroxyneopentate, tert-butyl peroxyneopentate, tert-pentyl peroxyneopentate, tert-pentyl peroxyneopentate, lauroyl peroxide, dilauroyl peroxide, and didecyl peroxide are among one or more of these. The photoinitiator comprises benzoin dimethyl ether (DMPA) and / or 1-hydroxycyclohexylphenyl ketone (Irgacure184).

[0027] In this invention, in step 1), the reaction temperature is 30~45℃, preferably 35~40℃; the reaction time is 10~20h, preferably 12~18h, and more preferably 14~16h.

[0028] In this invention, the number-average molecular weight of the polymethyl methacrylate is ≥80,000.

[0029] In this invention, the hollow microspheres include one or more of hollow glass microspheres, hollow silicon carbide microspheres, hollow ceramic microspheres, hollow plastic microspheres, hollow metal microspheres, and hollow carbon microspheres. The amount of hollow microspheres added is 5-30% of the total mass of the PMMA recyclable wave-absorbing buoyancy material, preferably 10-25%, and more preferably 15-20%.

[0030] In this invention, the hollow microspheres have a closed-cell structure with an average particle size of 10-100 micrometers, a wall thickness of 0.5-2 micrometers, and a tap density of 0.1-0.6 g / cm³. The introduction of hollow microspheres is not only key to achieving low density (<1 g / cm³) and high buoyancy in the material, but their closed spherical structure also effectively prevents water penetration, ensuring the long-term buoyancy stability of the material. Simultaneously, the numerous heterogeneous interfaces formed between the microspheres and the matrix and the absorbing agent enhance interfacial polarization and multiple scattering effects, synergistically improving electromagnetic wave loss.

[0031] In this invention, the wave-absorbing agent comprises one or more of carbon-based wave-absorbing agents, metal-based wave-absorbing agents, and magnetic wave-absorbing agents. The amount of wave-absorbing agent added is 1 to 30% of the total mass of the PMMA recyclable wave-absorbing buoyancy material, preferably 5 to 25%, and more preferably 10 to 20%.

[0032] In this invention, the carbon-based microwave absorbing agent is selected from at least one of carbon black, carbon nanotubes, graphene, and carbon fiber; the magnetic and metal-based microwave absorbing agent is selected from at least one of carbonyl iron powder, ferrite, and permalloy powder. By employing a low content of microwave absorbing agent, this invention ensures that the overall density of the material remains at a low level and facilitates impedance matching with free space, thereby achieving wide-bandwidth and high-efficiency microwave absorption performance.

[0033] The microwave absorbing agent of the present invention may also be: Ferrite-based microwave absorbers include, but are not limited to: MnZn ferrite, NiZn ferrite, Fe3O4 nanoparticles, cobalt-based ferrite (CoFe2O4), and M-type hexagonal ferrite (BaFe). 12 O 19 SrFe 12 O19 ).

[0034] Metallic magnetic microwave absorbers include, but are not limited to: carbonyl iron (CI), Fe, Co, Ni metal particles, FeCo alloy particles, CoNi alloy particles, and Ag / Cu / Ni metal nanoparticles.

[0035] Magnetic composite microwave absorbers include, but are not limited to: carbon-coated metal core-shell structures (Fe@C, Ni@C, Co@C), metal / oxide composite particles (Fe3O4@C, FeCo@SiO2, etc.), and multiphase composites (MXene@Fe3O4, RGO@Fe3O4).

[0036] Carbon-based microwave absorbers include, but are not limited to: graphene (RGO), carbon nanotubes (CNT), sheet graphite, conductive carbon black (CB), carbon microspheres, chopped carbon fibers, hollow carbon spheres, and porous carbon.

[0037] Ceramic microwave absorbers include, but are not limited to: SiC (including nano-silicon carbide and porous SiC), TiC, ZrC, HfC, Al2O3, ZnO, Si3N4, BN, AlN, and foam ceramic particles.

[0038] Two-dimensional microwave absorbing materials include, but are not limited to: MXene (Ti3C2Tx, etc.), MoS2, and BN nanosheets.

[0039] Metal-carbon composite microwave absorbers include, but are not limited to: Ni@C, Fe@C, Co@C core-shell structures, and metal nanoparticles supporting graphene (Fe3O4 / RGO, Co / RGO).

[0040] Magnetic-dielectric composite microwave absorbers include, but are not limited to: CNT / Fe3O4, RGO / Fe3O4, SiC / Fe, C / FeCo, and MXene / metal composite structures.

[0041] Porous absorbing structures include, but are not limited to: hollow carbon spheres, porous SiC, and foam ceramic particles.

[0042] The preferred microwave absorbing agents of this invention (especially suitable for direct mixing with hollow glass microspheres in a resin matrix as a microwave absorbing phase) are: Fe3O4 (magnetic iron oxide), MnZn / NiZn ferrite, FeCo / FeNi alloy nanoparticles, core-shell structures (Fe3O4@C, FeCo@C), graphene / rGO, CNT (carbon nanotubes), MXene (Ti3C2Tx, etc.), SiC / ZnO / MoS2 (semiconductor), metal nanoparticles (Ag / Cu / Ni), hollow carbon spheres / porous carbon, multiphase composites (MXene@Fe3O4, RGO@Fe3O4), carbonyl iron powder, and nano-silicon carbide.

[0043] The aforementioned microwave absorbing agent can be directly blended with hollow glass microspheres (HGM) in the resin matrix as a microwave absorbing phase to achieve a lightweight and efficient microwave absorbing composite material.

[0044] In this invention, the curing conditions are as follows: first, heat at 30~40℃ for 8~12h, then heat to 70~90℃ for 1~3h to complete curing; preferably, heat at 32~38℃ for 9~11h, then heat to 75~85℃ for 2~3h to complete curing.

[0045] The present invention also provides a recyclable PMMA wave-absorbing buoyancy material prepared by the above preparation method.

[0046] This invention also provides a method for recycling the PMMA recyclable microwave absorbing buoyancy material prepared by the above method, comprising the following steps: immersing or spraying the waste or damaged PMMA recyclable microwave absorbing buoyancy material in MMA solvent, utilizing the characteristic that the PMMA matrix is ​​soluble in its monomer MMA to redissolve the solid PMMA matrix; after the matrix is ​​completely dissolved, recovering the hollow microspheres and microwave absorbing agent that are insoluble in MMA through physical separation methods such as magnetic separation, filtration, centrifugation, or sedimentation, respectively; the recovered PMMA liquid resin, hollow microspheres, and microwave absorbing agent can be recycled.

[0047] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0048] Example 1

[0049] Preparation of a recyclable PMMA wave-absorbing buoyancy material, with the following mass fractions of each component: PMMA (number average molecular weight approximately 100,000): 20 parts MMA (including polymerization inhibitor): 80 parts Hollow glass microspheres: 20 parts Conductive carbon black: 10 parts Initiator BPO: 1.2 parts Initiator DMA: 1 part The preparation steps are as follows: (1) Add 20 parts of PMMA powder to 80 parts of MMA monomer, stir and dissolve at 35°C for 12 hours until PMMA is completely dissolved to form a viscous and transparent PMMA / MMA binary liquid resin.

[0050] (2) Cool the system to room temperature, add 20 parts of hollow glass microspheres, stir magnetically for 30 minutes to initially wet it; then add 10 parts of conductive carbon black, increase the stirring speed to 1000 rpm and combine with ultrasonic dispersion (power 300W, treatment for 15 minutes) to make the filler uniformly dispersed.

[0051] (3) Add 1.2 parts of initiator BPO and 1 part of initiator DMA, continue stirring for 10 minutes to mix the components evenly, and perform vacuum degassing treatment to eliminate the bubbles introduced during stirring.

[0052] (4) Slowly pour the above mixed slurry into an aluminum mold with dimensions of 180mm×180mm×3mm.

[0053] (5) Place the mold in an oven and heat it according to the program: first keep it at 35℃ for 10 hours, then heat it to 80℃ and keep it for 2 hours to complete the polymerization. After naturally cooling to room temperature, demold to obtain PMMA / carbon black / HGM recyclable wave-absorbing buoyancy material sample.

[0054] Performance testing: Density test: The measured sample density is less than 1.0 g / cm³.

[0055] Water absorption test: After the sample was soaked in deionized water for 30 days, the mass increase rate was less than 1%.

[0056] Electromagnetic parameter testing: The sample was tested using a vector network analyzer (coaxial method) and the RL ≤ -10dB was measured in the 2-18GHz range.

[0057] Example 2

[0058] A recyclable PMMA buoyancy-absorbing material was prepared using a magnetic absorbing agent. The mass fractions of each component are as follows: PMMA (number average molecular weight approximately 100,000): 30 parts MMA: 70 copies Hollow glass microspheres: 18 parts Carbonyl iron powder (average particle size 3-5μm): 10 parts Initiator BPO: 1.2 parts Initiator DMA: 1 part Preparation steps: (1) To prepare PMMA / MMA binary liquid resin, 30 parts of PMMA powder were added to 70 parts of MMA monomer and stirred at a constant temperature of 35°C for 12 hours until PMMA was completely dissolved to form a transparent binary liquid resin.

[0059] (2) Add 18 parts of hollow glass microspheres and 10 parts of carbonyl iron powder to the resin system, stir at high speed and ultrasonically disperse to make them evenly distributed.

[0060] (3) Add 1.2 parts of initiator BPO and 1 part of initiator DMA, stir evenly and pour into the mold.

[0061] (4) Curing process: First, heat at 35℃ for 10 hours, then heat to 80℃ and heat for 2 hours to complete the polymerization. After naturally cooling to room temperature, demold to obtain PMMA / carbonyl iron powder / HGM recyclable wave-absorbing buoyancy material sample.

[0062] Performance testing: Density test: The measured sample density is less than 1.0 g / cm³.

[0063] Water absorption test: After the sample was soaked in deionized water for 30 days, the mass increase rate was less than 1%.

[0064] Electromagnetic parameter testing: The sample was tested using a vector network analyzer (coaxial method) and the RL ≤ -10dB was measured in the 2-18GHz range.

[0065] Example 3

[0066] Preparation of a recyclable PMMA microwave-absorbing buoyancy material, a composite microwave-absorbing agent system, with the following mass proportions of each component: Components and proportions (parts by mass) PMMA (number average molecular weight approximately 100,000): 20 parts MMA (including polymerization inhibitor): 70 parts MAA: 10 copies Hollow glass microspheres (actual density 0.3 g / cm³): 25 parts Multi-walled carbon nanotubes (diameter 10-20 nm, length 1-5 μm): 5 parts Nano-nickel-zinc ferrite (particle size 50-100nm): 10 parts Initiator BPO: 1.2 parts Initiator DMA: 1 part Preparation steps Add 20 parts PMMA powder to a mixture of 70 parts MMA and 10 parts MAA monomers, and stir at a constant temperature of 35°C for 12 hours until the PMMA is completely dissolved to form a transparent ternary liquid resin.

[0067] Mix 5 parts carbon nanotubes and 10 parts nano nickel-zinc ferrite evenly, add them to the PMMA / MMA / MAA resin system, stir at low speed (500 rpm) for 20 minutes, then stir at high speed (1500 rpm) and combine with ultrasonic dispersion (350W power, 20 minutes) to ensure uniform dispersion of the microwave absorber.

[0068] Add 25 parts of hollow glass microspheres and use planetary stirring (800 rpm) for 30 minutes to ensure that the microspheres are evenly dispersed and not damaged.

[0069] Add 1.2 parts of initiator BPO and 1 part of initiator DMA, stir for 5 minutes and then perform vacuum degassing (-0.09MPa, 5 minutes).

[0070] The mixed slurry was poured into a mold and kept at 35°C for 10 hours, then heated to 80°C and kept at that temperature for 2 hours to complete the polymerization. After naturally cooling to room temperature, the material was demolded to obtain a PMMA / carbon nanotube-nano nickel-zinc ferrite / HGM composite material sample.

[0071] Performance testing

[0072] Density test: The measured sample density is less than 1.0 g / cm³.

[0073] Water absorption test: After the sample was soaked in deionized water for 30 days, the mass increase rate was less than 1%.

[0074] Electromagnetic parameter testing: The sample was tested using a vector network analyzer (coaxial method) and the RL ≤ -10dB was measured in the 2-18GHz range.

[0075] Example 4 (Recycling Process)

[0076] A recycling experiment was conducted on the waste sample prepared in Example 2.

[0077] (1) Crush 20 grams of the material sample prepared in Example 2 into fragments with a size of less than 5 mm.

[0078] (2) Place the fragments in 500 mL of MMA solvent, seal and soak at room temperature for 12 hours. It can be seen that the material fragments completely disintegrate and the PMMA matrix dissolves in the MMA solvent to form a mixed solution containing carbonyl iron powder and hollow glass microspheres.

[0079] (3) The solution is centrifuged to allow the carbonyl iron powder and hollow glass microspheres to settle. The supernatant (i.e., PMMA / MMA solution, which can be recycled for the preparation of composite materials) and the solid precipitate are separated. The precipitate is washed and dried with MMA to obtain the recovered mixture of carbonyl iron powder and hollow glass microspheres.

[0080] (4) The carbonyl iron powder and hollow glass microsphere mixture recovered in (3) was separated by magnetic separation to obtain pure carbonyl iron powder and hollow glass microspheres.

[0081] Experimental results show that the material provided by this invention has excellent recyclability, and all components can be efficiently separated and reused, demonstrating outstanding environmental friendliness.

[0082] As shown in the above embodiments, this invention provides a recyclable PMMA microwave-absorbing buoyancy material and its preparation method. This invention achieves both electromagnetic wave absorption and buoyancy bearing functions by constructing a low-density, closed-cell polymer composite system. The resulting material has a density lower than water and possesses long-term buoyancy; through interfacial polarization and multiple scattering effects, stable microwave absorption performance (RL≤-10 dB) is obtained while ensuring good impedance matching. Most importantly, utilizing the characteristic that the PMMA matrix is ​​soluble in methyl methacrylate (MMA) monomers, the entire component of the material—the matrix, hollow microspheres, and microwave absorber—can be recovered through simple solvent immersion or spraying, solving the problem of difficult recycling of traditional functional composite materials, and possessing significant economic and environmental benefits.

[0083] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a recyclable PMMA wave-absorbing buoyancy material, characterized in that, Includes the following steps: 1) Polymethyl methacrylate and acrylic resin monomers are reacted under the action of a free radical initiator to obtain a PMMA liquid resin with a certain viscosity; 2) Hollow microspheres and microwave absorbing agent are added to PMMA liquid resin for dispersion treatment to obtain a suspension slurry; 3) The mixture is solidified and molded in a mold to obtain the PMMA recyclable wave-absorbing buoyancy material.

2. The method for preparing the PMMA recyclable wave-absorbing buoyancy material according to claim 1, characterized in that, The acrylic resin monomer comprises methyl methacrylate and / or methacrylic acid; The mass ratio of polymethyl methacrylate to acrylic resin monomer is 5~30:70~95.

3. The method for preparing the PMMA recyclable wave-absorbing buoyancy material according to claim 2, characterized in that, The free radical initiator includes a thermal initiator or a photoinitiator; The amount of the free radical initiator added is 1 to 5% of the total mass of polymethyl methacrylate and acrylic resin monomers.

4. The method for preparing the PMMA recyclable wave-absorbing buoyancy material according to any one of claims 1 to 3, characterized in that, In step 1), the reaction temperature is 30~45℃ and the reaction time is 10~20h.

5. The method for preparing the PMMA recyclable wave-absorbing buoyancy material according to claim 1, characterized in that, The polymethyl methacrylate has a number average molecular weight ≥ 80,000.

6. The method for preparing the PMMA recyclable wave-absorbing buoyancy material according to claim 4, characterized in that, The hollow microspheres include one or more of hollow glass microspheres, hollow silicon carbide microspheres, hollow ceramic microspheres, hollow plastic microspheres, hollow metal microspheres, and hollow carbon microspheres, and the amount of hollow microspheres added is 5 to 30% of the total mass of the PMMA recyclable wave-absorbing buoyancy material.

7. The method for preparing the PMMA recyclable wave-absorbing buoyancy material according to claim 6, characterized in that, The hollow microspheres have a closed-cell structure and a tap density of 0.1~0.6 g / cm³.

8. The method for preparing the PMMA recyclable wave-absorbing buoyancy material according to claim 1, 6, or 7, characterized in that, The absorbing agent comprises one or more of carbon-based absorbing agents, metal-based absorbing agents, and magnetic absorbing agents, and the amount of the absorbing agent added is 1 to 30% of the total mass of the PMMA recyclable absorbing buoyancy material.

9. The method for preparing the PMMA recyclable wave-absorbing buoyancy material according to claim 8, characterized in that, The curing conditions are as follows: first, keep the temperature at 30~40℃ for 8~12 hours, then raise the temperature to 70~90℃ and keep it at 1~3 hours to complete the curing.

10. The PMMA recyclable wave-absorbing buoyancy material prepared by the preparation method according to any one of claims 1 to 9.

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