A method for preparing a high-performance hollow glass microsphere / epoxy resin floating material

Abstract

The present invention belongs to the technical field of the preparation of solid floating body materials, and particularly relates to a method for preparing a high-performance hollow glass microsphere / epoxy resin floating body material. After uniformly mixing the surface-treated hollow glass microspheres with polyether ether ketone, they are vibrated and compacted in a mold and heated to 370 °C - 380 °C, kept warm for 15 - 20 min and then cooled to room temperature to obtain a porous preform; a liquid epoxy resin and a curing agent mixed liquid are poured into the porous preform and cured to obtain a high-performance hollow glass microsphere / epoxy resin floating body material. In the floating body material prepared by the present invention, the hollow glass microspheres have a complete structure, a high filling rate and a uniform distribution, the floating body material has no gas phase, and the strength is significantly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of solid floating material, and particularly relates to a method for preparing a high-performance hollow glass microsphere / epoxy resin floating material. Background Art

[0002] Solid floating materials (also known as solid buoyancy materials) play a key role in deep-sea equipment and are extremely crucial core materials in ocean exploration and deep-sea engineering. Solid floating materials can generally be divided into three categories: chemically foamed floating materials and composite lightweight floating materials (two-phase composite foam materials, three-phase composite foam materials). In two-phase composite foam materials, there are only lightweight fillers and resin matrices, while in three-phase composite foam materials, there are irregular bubble phases.

[0003] Hollow microsphere floating materials are mainly prepared by thermosetting of hollow glass microspheres and resin substrates, and are the most reported type of solid floating materials at home and abroad. The microspheres filled in hollow microsphere materials are mainly divided into two categories: inorganic and organic. Inorganic microspheres mainly include SiO2, Al2O3, ceramics, etc., and organic microspheres include epoxy, phenolic, and polystyrene spheres, etc. Common resins include epoxy resin, phenolic resin, unsaturated polyester, etc. The forming methods are generally stirring casting method, vacuum impregnation method, etc. This kind of material has the characteristics of low density, high strength, resistance to hydrostatic external pressure, resistance to seawater corrosion, low water absorption, etc., can withstand huge pressures underwater for thousands of meters, and its own density is lower than the density of water, and can provide buoyancy to support underwater robots and its own weight.

[0004] However, at present, the forming process of hollow microsphere floating materials mostly adopts the stirring casting method, and this method has the following problems: The density of HGM (hollow glass microspheres) is lower than that of the polymer, and the microspheres will float during the stirring process, resulting in poor uniformity of the composite material; too high stirring speed will cause the microspheres to break, thus increasing the density of the composite material; when preparing high-volume fraction HGM composite hollow microsphere floating materials, due to the low polymer content, the viscosity of the mixed slurry of microspheres and polymer will be too high and not conducive to stirring, and air bubbles that are difficult to remove will be mixed into the material during the stirring process, seriously affecting the performance of the composite material.

[0005] Song Yuting et al. mixed two different types of modified hollow glass microspheres in proportion, then stirred, cast, and cured them with an epoxy resin system to obtain a composite floating material of mixed hollow glass microspheres. Mixing hollow glass microspheres with different particle sizes can increase the filling rate of hollow glass microspheres in the composite material and effectively reduce the density of the composite material. However, the problems of poor uniformity of the composite material caused by the stirring and casting method and the entrapment of air bubbles inside the material have not been solved (Chinese Patent Application No.: CN112694717B). Liang Xiaojie et al. prepared the composite material by the vacuum impregnation method and degassed multiple times during the addition of raw materials, effectively removing most of the air bubbles in the preparation of the composite material. However, the shape of the mold is required during the vacuum impregnation process. Due to the tiny gaps between the hollow glass microspheres, the epoxy resin may not be able to fully infiltrate and flows out from the glue outlet (Chinese Patent Application No.: CN110698815B). Tang Bo et al. grafted polyether ether ketone on the surface of hollow glass microspheres and then mixed them with epoxy resin and used the stirring and casting method to prepare the floating material. After testing, it was found that there was a phenomenon of uneven distribution of hollow glass microspheres in the epoxy resin matrix (Chinese Patent Application No.: CN103865235A). Shi Qiankun et al. used polyethylene, polypropylene, and polyamide to replace conventional epoxy resin as the matrix material, fed the matrix mixture and the modified hollow glass microspheres into a twin-screw extruder, and after the extruder melted and extruded the material, it was then cooled by molding to obtain a solid floating material. They achieved mass production using a screw extruder, with high automation and low labor costs. However, since the material forming process is implemented by machinery, it cannot specifically solve the problem of poor material uniformity, and a large number of air bubbles will be entrapped during the forming process and cannot be removed, which will affect the mechanical properties of the material (Chinese Patent Application No.: CN202410336855.5). An Zhenguo et al. used hollow composite microspheres with a double-layer spherical shell structure where the outer spherical shell is a metal oxide and the inner spherical shell is a silicate glass. They mixed the resin and the curing agent with the hollow composite microspheres respectively, and then mixed and vibrated the two mixtures to remove air bubbles, obtaining a lightweight and high-strength solid floating material. Although this method has a degassing process, it does not solve the problem of poor material uniformity caused by the floating of microspheres during the mixing process of microspheres and the matrix (Chinese Patent Application No.: 202011108682.X). Summary of the Invention

[0006] In view of the deficiencies of the prior art, the present invention proposes a method for preparing a high-performance hollow glass microsphere / epoxy resin floating material. This method can increase the filling rate of hollow glass microspheres in the epoxy resin matrix, remove the gas entrapped during the filling process of hollow glass microspheres at the same time, avoid the pore defects remaining in the cured material, and effectively enhance the mechanical properties of the floating material.

[0007] To achieve the above objectives, the technical solution of the present invention is realized through the following technical solutions:

[0008] A method for preparing a high-performance hollow glass microsphere / epoxy resin floating material, and its preparation process is as follows:

[0009] (1) Hydroxylate and coat the hollow glass microspheres with a coupling agent to obtain surface-treated hollow glass microspheres;

[0010] (2) Mix the surface-treated hollow glass microspheres and polyether ether ketone evenly in proportion, put them into a mold and then sinter them in a muffle furnace. The sintering process is: heat at a heating rate of 5-10 °C / min to 370 °C - 380 °C and keep warm for 15-20 min, cool, and then demold to obtain a porous preform; the mass ratio of the surface-treated hollow glass microspheres to polyether ether ketone is 30:4-8;

[0011] (3) Mix the epoxy resin and the curing agent in proportion and stir evenly to obtain an epoxy resin mixture;

[0012] (4) Place the porous preform obtained in step (2) in a cavity mold, inject the epoxy resin mixture obtained in step (3), evacuate and keep the pressure for a period of time, heat and cure, cool, and then demold.

[0013] Since the hollow glass microspheres have a hollow structure and a good heat insulation effect, if the heating rate is too low, the forming speed will be affected. If the heating rate is too fast, the polyether ether ketone in the edge area will melt too quickly, while the central glass remains in a powder solid state, which will have an adverse effect on the forming of the porous preform.

[0014] Using a high-temperature resistant coupling agent can avoid the volatilization of the coupling agent in the high-temperature environment of 370 °C - 380 °C during the preparation of the preform, resulting in a decrease in the interfacial bonding strength between the hollow glass microspheres, the epoxy resin and the polyether ether ketone, and ultimately affecting the performance of the composite material. KH-792 with high temperature resistance is used. One reason is that KH-792 has high temperature resistance, and the other reason is that the epoxy group (γ-glycidyl group) of KH-792 can chemically react with the hydroxyl group or amino group in the epoxy resin to form strong covalent bonds, thus ensuring high bonding strength with the epoxy matrix. At the same time, its trimethoxysilyl group forms stable silicon-oxygen bonds (Si-O-Si) with the hydroxyl groups on the glass surface through hydrolysis, significantly enhancing the interfacial bonding performance between the glass and the organic matrix. This dual function gives KH-792 significant advantages in improving the interfacial bonding strength and durability of the composite material. And the bonding stability of KH-792 is better under humid and long-term service conditions. Therefore, through the surface modification of the hollow glass microspheres, the interfacial bonding force between them and the polyether ether ketone can be improved, and the bonding between the hollow glass microspheres and the polyether ether ketone can be made closer.

[0015] In a preferred embodiment, step (2) is specifically as follows: Mix the surface-treated hollow glass microspheres with polyetheretherketone powder and pour them into a mold. Place the mold containing the surface-treated hollow glass microspheres and polyetheretherketone powder on a vibrating device and vibrate for a period of time to make the polyetheretherketone powder mix evenly and densely accumulate on the surface of the hollow glass microspheres. Then, put the mold containing the densely packed polyetheretherketone powder and hollow glass microspheres into a muffle furnace, gradually heat it to 370°C - 380°C, keep it warm for 15 - 20 min, cool it to room temperature, and demold to obtain a hollow glass microsphere / polyetheretherketone porous preform. If the temperature is lower than 370°C, the preform cannot be formed; if the temperature is too high (for example, above 400°C), the polyetheretherketone (PEEK) will undergo thermal degradation, manifested as the breakage of molecular chains, generating harmful gases or degradation products, and the color of the material will also become darker or yellowish.

[0016] In step (2), the mold for containing the surface-treated hollow glass microspheres and polyetheretherketone is a quartz mold.

[0017] Before the hydroxylation and coupling agent coating treatment of the hollow glass microspheres in step (1), a flotation treatment is carried out on the hollow glass microspheres; in the flotation treatment, the operation steps are as follows: Mix the hollow glass microspheres with pure water in proportion, stir at a certain rotation speed, let it stand for a certain time, then take the upper-layer microspheres and dry them to obtain the flotation-treated hollow glass microspheres; in the flotation treatment, when the hollow glass microspheres are soaked in pure water, the volume ratio of the hollow glass microspheres to water is 1:8 - 12; in the flotation treatment, the stirring duration is 5 - 15 min, and after stirring, it needs to stand for another 1 - 3 h.

[0018] In step (1), the hollow glass microspheres are hydroxylated with a 0.6 - 1.0 mol / L NaOH solution, and stirring is carried out during the hydroxylation treatment; during the hydroxylation treatment, the temperature is 40 - 60°C, the treatment time is 1.5 - 2.5 h, and the stirring rate is 300 - 500 rpm; the mass-volume ratio of the hollow glass microspheres to the NaOH solution is 1 g:(8 - 12) mL.

[0019] During the coupling agent coating treatment process, the hydroxylated hollow glass microspheres are placed in an ethanol solution, which is composed of anhydrous ethanol and deionized water mixed in a volume ratio of 1:3, and then a high-temperature resistant silane coupling agent is added, and stirring treatment is carried out at 70 - 90°C for 1.5 - 2.5 h; take the surface-treated hollow glass microspheres, wash them, and dry them at 110 - 120°C to complete the curing of the coupling agent and the formation of chemical bonds.

[0020] During the coupling agent coating treatment process, the coupling agent used is the high-temperature resistant silane coupling agent KH-792, and the mass ratio of the coupling agent to the hydroxylated hollow glass microspheres is 1:7-13; the mass-volume ratio of the hydroxylated hollow glass microspheres to the ethanol solution is 1 g:(20-40) mL.

[0021] In step (3), the mass ratio of the epoxy resin to the curing agent is 2.5-3.5:1; the epoxy resin is a liquid epoxy resin.

[0022] In step (3), the epoxy resin is E-51 epoxy resin, and the curing agent uses the amine curing agent HS-273M.

[0023] Step (4) is specifically as follows: Place the porous preform obtained in step (2) in a mold, pour the epoxy resin mixture obtained in step (3) into the mold, and make the epoxy resin mixture just submerge the porous preform (the open pore rate of the porous preform is a, and a is subject to actual measurement. The volume of the porous preform is V. When preparing the porous preform in step (2), the porous preform fills the inner cavity of the mold, and the volume of the inner cavity of the mold is V. When the epoxy resin mixture just submerges the porous preform, the volume of the epoxy resin mixture is V*(a + 1%) to V*(a + 3%); Place the entire mold in a vacuum chamber, evacuate and maintain pressure until the epoxy resin stops boiling, and a hollow glass microsphere preform filled with liquid epoxy resin is formed in the mold; Take out the hollow glass microsphere preform filled with liquid epoxy resin together with the mold, heat it to 70-90 °C and keep it warm for 4-6 h, cool it after curing, and demold to obtain the final floating body material.

[0024] Preferably, before the hydroxylation and coupling agent coating treatment of the hollow glass microspheres in step (1), the hollow glass microspheres are subjected to flotation treatment: When soaking the hollow glass microspheres in pure water, the volume ratio of the hollow glass microspheres to water is 1:10. The stirring duration is 10 min, and after stirring, it needs to be left standing for 2 h. The specific operation of the flotation treatment is: Mix and stir the hollow glass microspheres and pure water in proportion, take the upper-layer microspheres after standing, filter and dry them by suction to obtain the flotation-treated hollow glass microspheres.

[0025] In this article, taking the upper-layer microspheres means taking the microspheres floating on the water surface, which is to remove the microspheres with damaged surfaces that cannot float normally.

[0026] Preferably, when the hollow glass microspheres are hydroxylated in step (1), the concentration of the NaOH solution is 0.75 mol / L. The dosage of the hollow glass microspheres is 10 g per 100 mL of the NaOH solution. The water bath stirring temperature is 50 °C, the stirring duration is 2 h, and the stirring rate is 400 rpm. The specific operation is as follows: Add an appropriate amount of hollow glass microspheres to 100 mL of the NaOH solution, and stir in a water bath for a period of time. Take the upper-layer hollow glass microspheres after stirring, wash them with deionized water until neutral, filter them by suction and dry them to obtain the hydroxylated hollow glass microspheres.

[0027] Preferably, in the step (1) of coating the hydroxylated hollow glass microspheres with a coupling agent, the ethanol solution is prepared by mixing absolute ethanol and deionized water in a volume ratio of 1:3. The ethanol solution required for every 10 g of the hollow glass microspheres is 300 mL. The dosage of the coupling agent is 1 g. The specific operation is as follows: Place the hydroxylated hollow glass microspheres in the ethanol solution, add 1 g of the coupling agent, and stir in a water bath for a period of time. Take the upper-layer hollow glass microspheres after stirring, wash the microspheres with deionized water, filter them by suction and dry them to finally obtain the surface-treated hollow glass microspheres.

[0028] Preferably, in the step (2), the material ratio (mass ratio) of the surface-treated hollow glass microspheres to the polyetheretherketone powder is 30:4, 30:5, 30:6, 30:7, 30:8.

[0029] Preferably, in the step (2), the mixing and sintering temperature of the surface-treated hollow glass microspheres and the polyetheretherketone is 370 °C.

[0030] Preferably, in the step (2), the mold for containing the surface-treated hollow glass microspheres and the polyetheretherketone is a quartz mold.

[0031] Preferably, in the step (2), the specific operation is to mix the surface-treated hollow glass microspheres and the polyetheretherketone powder and then pour them into a quartz mold. Place the mold on a shaking device and shake for a period of time (10 - 20 min) to make the powder mix evenly and densely packed. Then, put the mold containing the densely packed powder and the hollow glass microspheres into a muffle furnace, heat it to 370 °C according to the preset sintering procedure, keep it at 370 °C for a certain period of time, take out the mold, and demold it after it cools to room temperature to obtain the hollow glass microsphere / polyetheretherketone porous preform.

[0032] Preferably, in the step (3), the dosage ratio (mass ratio) of the epoxy resin to the curing agent is 3:1.

[0033] Preferably, in step (3), the porous preform obtained in step (2) is placed in a silicone rubber mold, and the epoxy resin mixture obtained in step (3) is poured into the silicone rubber mold and submerges the porous preform. The entire silicone rubber mold is placed in a small vacuum chamber. After vacuumizing and maintaining pressure for 20 minutes, no boiling phenomenon of the epoxy resin is observed. The hollow glass microsphere preform filled with liquid epoxy resin is taken out together with the mold, heated and cured, and then naturally cooled and demolded to obtain the final floating body material.

[0034] The processing temperature of polyetheretherketone powder will soften above 370 °C and will cure when the temperature decreases. The operation steps of the present invention are to uniformly mix two powders of polyetheretherketone and hollow glass microspheres, raise the temperature to 370 °C - 380 °C to soften the polyetheretherketone, and then cool down, and the polyetheretherketone will cure to bond the hollow glass microspheres into a block. Too little polyetheretherketone cannot completely bond the hollow glass microspheres together to form a floc, and cannot play a role in fixing the hollow glass microspheres.

[0035] In material design, different materials are very sensitive to temperature. For example, in the present invention, when using polyetheretherketone to bond hollow glass microspheres to prepare a porous preform, the temperature must reach 370 °C. Even 360 °C or even 365 °C will not result in successful preparation.

[0036] In the present invention, the surface-treated hollow glass microspheres and polyetheretherketone are mixed to prepare a preform. The phenolic hydroxyl groups on the end groups of polyetheretherketone can be cured together with epoxy resin. The hybridization of epoxy resin and the thermoplastic phase can reduce brittleness and improve toughness without damaging the thermal properties and mechanical properties. And after grafting hydroxyl groups and silane coupling agents on the surface of the hollow glass microspheres, the hydroxyl groups and silane coupling agents enhance the bonding performance between the hollow glass microspheres and polyetheretherketone. After forming the preform, polyetheretherketone can also improve the interfacial bonding force between the hollow glass microspheres and epoxy resin. The curing of polyetheretherketone and epoxy resin together improves the performance of the composite material. After grafting silane coupling agents on the surface of the hollow glass microspheres, the surface will be cured with epoxy resin through epoxy groups to improve the performance of the composite material. That is to say, the method of the present invention can achieve composite effects such as toughening, strengthening, increasing the microsphere filling rate, and dispersibility. This cannot be achieved by simply using epoxy resin and curing agent.

[0037] The present invention retains the integrity of the hollow structure of the hollow glass microspheres: If the preform is prepared by utilizing the characteristic that the hollow glass microspheres soften and bond together at a high temperature (about 700 °C), the hollow glass microspheres will deform and lose their hollow spherical characteristics, which will affect the strength and density of the composite material. And at a high temperature (about 700 °C), the coupling agent grafted on the surface of the hollow glass microspheres detaches from the surface of the hollow glass microspheres, resulting in a decrease in the interfacial bonding force between the subsequent hollow glass microspheres and epoxy resin, affecting the strength of the composite material.

[0038] In the present invention, a relatively small amount of polyether ether ketone is used, which will not cause the problem of uneven distribution of microbeads. On the contrary, because the amount is much less than that of the microbeads and epoxy resin, the hollow glass microbeads will be fixed in the optimal packing manner when preparing the preform. If the amount of polyether ether ketone is too much, it will replace the position of the hollow glass microbeads, have a great impact on the filling amount of the hollow glass microbeads, and ultimately affect the performance of the composite material.

[0039] The beneficial effects of the present invention are as follows:

[0040] In the present invention, the porous preform prepared by pre-firing the microbeads at low temperature is placed in a specific mold, then the mold is evacuated, and then resin is poured in to make the resin fill the gaps between the hollow glass microbeads. Finally, it is cured and formed to obtain a solid floating body material. The solid floating body material obtained by this method has good uniformity, a high filling ratio of microbeads, and because the bubble defects are removed during the forming process, the mechanical properties of the material are significantly improved.

[0041] The present invention has the following four advantages: (1) Changing from the high-temperature sintering method to the resin bonding method (using the thermoplastic resin PEEK to bond the hollow glass microbeads to prepare a porous ceramic preform). High-temperature sintering will cause the hollow glass microbeads to deform from a hollow spherical shell to a polygonal shell, affecting the performance of the final floating body material, while the porous ceramic preform does not affect the shape of the hollow glass microbeads at all; (2) Greatly reducing the floating of the hollow glass microbeads due to density reasons, making the filling of the hollow glass microbeads in the resin matrix more uniform; (3) Not involving the mixing and stirring of the hollow glass microbeads and epoxy resin, reducing the breakage rate of the hollow glass microbeads; (4) Removing the gas mixed in during the filling process of the hollow glass microbeads, avoiding the residual pore defects in the cured material, and improving the mechanical properties of the floating body material. Brief Description of the Drawings

[0042] Figure 1 Flow chart for preparing the floating body material of the present invention;

[0043] Figure 2 Macroscopic and microscopic morphologies of the HGM porous preform, a, macroscopic morphology, b, microscopic morphology;

[0044] Figure 3 Successful or failed preforms: (a) Example 1, (b) Comparative Example 6;

[0045] Figure 4 Compression diagram of the floating body material of the present invention;

[0046] Figure 5 Stress-strain curve diagram of the epoxy resin matrix;

[0047] Figure 6Stress-strain curve diagram of porous preform / epoxy resin composite floating body materials made of different proportions of microbeads and polyether ether ketone;

[0048] Figure 7 Microstructure of the floating body material of the present invention;

[0049] Figure 8 Longitudinal cracks appearing along the pressure direction inside the specimen under compressive stress;

[0050] Figure 9 Preparation flow chart of hollow glass microbead / polyether ether ketone porous preform;

[0051] Figure 10 Particle size distribution diagram of hollow glass microbeads. Detailed implementation manners

[0052] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0053] The stirring speed in the following examples and comparative examples is 400 rpm. The particle size of the hollow glass microbeads in the following examples and comparative examples is 20 - 120 μm.

[0054] Example 1

[0055] A method for preparing a high-performance hollow glass microbead / epoxy resin floating body material, the preparation steps are as follows:

[0056] Pour 900 mL of deionized water into a beaker, add 90 mL of hollow glass microbeads, stir at room temperature for 10 min, let stand for 2 h, and take the upper-layer hollow glass microbeads for suction filtration and drying.

[0057] Place 20 g of the well-flotation hollow glass microbeads in 200 mL of NaOH solution with a solution concentration of 0.75 mol / L, stir at 50 °C for 2 h, let stand for 30 min after stirring, wash the hollow glass microbeads with deionized water until neutral, and then perform suction filtration and drying to obtain hydroxylated hollow glass microbeads.

[0058] Place 10 g of the hydroxylated hollow glass microbeads in a mixed solution of 300 mL of ethanol and deionized water mixed by a volume ratio of 1:3. Add 1 g of coupling agent KH-792. Under the condition of 80 °C, use mechanical stirring for 2 h. After the reaction, wash with deionized water, perform suction filtration and drying (110 °C) to obtain surface-treated hollow glass microbeads.

[0059] After surface-treated hollow glass microspheres and polyether ether ketone are mixed at a mass ratio of 30:4, they are poured into a quartz mold. The mold is placed on a vibrating device and vibrated for 15 minutes. Then the mold is put into a muffle furnace and heated to 370 °C according to a preset sintering program (heating 7 °C per minute. Since the hollow glass microspheres have a hollow structure and good heat insulation effect, if the heating rate is too low, the forming speed will be affected; if the heating rate is too fast, the polyether ether ketone in the edge area will melt too quickly while the central glass remains in a powder solid state, which has an adverse effect on the forming of the porous preform). Keep it at 370 °C for 15 minutes, take out the mold, and demold it after it cools to room temperature to obtain a hollow glass microsphere / polyether ether ketone porous preform.

[0060] Epoxy resin and a curing agent are mixed at a mass ratio of 3:1 and stirred evenly to obtain an epoxy resin mixture.

[0061] The obtained porous preform is placed in a silicone rubber mold, and the epoxy resin mixture is poured into the silicone rubber mold to just submerge the porous preform. The whole silicone rubber mold is placed in a small vacuum chamber, evacuated and pressurized for 20 minutes, and no boiling phenomenon of the epoxy resin is observed. The hollow glass microsphere preform filled with liquid epoxy resin is taken out together with the mold, heated to 80 °C and kept warm for 5 hours for curing, and then naturally cooled and demolded after curing.

[0062] Among them, the macroscopic and microscopic morphologies of the HGM porous preform obtained in this example are as Figure 2 shown. Polyether ether ketone plays an adhesive role, bonding the hollow glass microspheres into a block with a certain strength structure. The main purpose of forming the preform is to fix the hollow glass microspheres, so that the hollow glass microspheres can be evenly dispersed in the epoxy resin matrix.

[0063] Example 2

[0064] A method for preparing a high-performance hollow glass microsphere / epoxy resin floating material, and the preparation steps are as follows:

[0065] Pour 900 mL of deionized water into a beaker, add 90 mL of hollow glass microspheres, stir at room temperature for 10 minutes, let it stand for 2 hours, and take the upper-layer hollow glass microspheres for suction filtration and drying.

[0066] Put 20 g of floated hollow glass microspheres into 200 mL of NaOH solution with a solution concentration of 0.75 mol / L, stir at 50 °C for 2 hours, let it stand for 30 minutes after stirring, wash the hollow glass microspheres with deionized water until neutral, and then perform suction filtration and drying to obtain hydroxylated hollow glass microspheres.

[0067] Place 10 g of hydroxylated hollow glass microspheres into a mixed solution of 300 mL of ethanol and deionized water mixed at a volume ratio of 1:3. Add 1 g of coupling agent KH-792. Under the condition of 80 °C, use mechanical stirring for 2 h. After the reaction, wash with deionized water, filter by suction and dry (at 110 °C) to obtain surface-treated hollow glass microspheres.

[0068] Mix the surface-treated hollow glass microspheres and polyether ether ketone at a mass ratio of 30:5 and pour them into a quartz mold. Place the mold on a shaking device and shake for 15 min. Then put the mold into a muffle furnace and heat it up to 370 °C according to a preset sintering program (heating 5 °C per minute), keep it at 370 °C for 15 min, take out the mold, and demold it after it cools to room temperature to obtain a hollow glass microsphere / polyether ether ketone porous preform.

[0069] Mix epoxy resin and a curing agent at a mass ratio of 3:1 and stir evenly to obtain an epoxy resin mixture.

[0070] Place the obtained porous preform into a silicone rubber mold, pour the epoxy resin mixture into the silicone rubber mold to just submerge the porous preform. Place the entire silicone rubber mold in a small vacuum chamber, evacuate and maintain pressure for 20 min, and observe that there is no boiling phenomenon of the epoxy resin. Take out the hollow glass microsphere preform filled with liquid epoxy resin together with the mold, heat it to 80 °C and keep it warm for 4 h for curing, and after curing, let it cool naturally and demold.

[0071] Example 3

[0072] A method for preparing a high-performance hollow glass microsphere / epoxy resin floating material, and the preparation steps are as follows:

[0073] Pour 900 mL of deionized water into a beaker, add 90 mL of hollow glass microspheres, stir at room temperature for 10 min, let it stand for 2 h, and take the upper-layer hollow glass microspheres for suction filtration and drying.

[0074] Place 20 g of well-flotation hollow glass microspheres into 200 mL of NaOH solution with a solution concentration of 0.75 mol / L, stir at 50 °C for 2 h, let it stand for 30 min after stirring, wash the hollow glass microspheres with deionized water until neutral, and then filter by suction and dry to obtain hydroxylated hollow glass microspheres.

[0075] Place 10 g of hydroxylated hollow glass microspheres into a mixed solution of 300 mL of ethanol and deionized water mixed at a volume ratio of 1:3. Add 1 g of coupling agent KH-792. Under the condition of 80 °C, use mechanical stirring for 2 h. After the reaction, wash with deionized water, filter by suction and dry (at 110 °C) to obtain surface-treated hollow glass microspheres.

[0076] The surface-treated hollow glass microspheres and polyether ether ketone were mixed at a mass ratio of 30:6 and poured into a quartz mold. The mold was placed on a shaking device and shaken for 15 minutes. Then the mold was put into a muffle furnace and heated to 380 °C according to a preset sintering program (heating 10 °C per minute), held at 370 °C for 15 minutes, taken out the mold, and demolded after it cooled to room temperature to obtain a hollow glass microsphere / polyether ether ketone porous preform.

[0077] Epoxy resin and a curing agent were mixed at a mass ratio of 3:1 and stirred evenly to obtain an epoxy resin mixture.

[0078] The obtained porous preform was placed in a silicone rubber mold, and the epoxy resin mixture was poured into the silicone rubber mold to just submerge the porous preform. The whole silicone rubber mold was placed in a small vacuum chamber, evacuated and pressurized for 20 minutes, and no boiling phenomenon of the epoxy resin was observed. The hollow glass microsphere preform filled with liquid epoxy resin was taken out together with the mold, heated to 80 °C and held for 6 hours for curing, and naturally cooled after curing and demolded.

[0079] Example 4

[0080] A method for preparing a high-performance hollow glass microsphere / epoxy resin floating material, the preparation steps are as follows:

[0081] 900 mL of deionized water was poured into a beaker, 90 mL of hollow glass microspheres was added, stirred at room temperature for 10 minutes, left standing for 2 hours, and the upper-layer hollow glass microspheres were taken and filtered and dried.

[0082] 20 g of the floated hollow glass microspheres were placed in 200 mL of NaOH solution with a solution concentration of 0.75 mol / L, stirred at 50 °C for 2 hours, left standing for 30 minutes after stirring, washed the hollow glass microspheres with deionized water until neutral, and then filtered and dried to obtain hydroxylated hollow glass microspheres.

[0083] 10 g of the hydroxylated hollow glass microspheres were placed in a mixed solution of 300 mL of ethanol and deionized water mixed at a volume ratio of 1:3. 1 g of coupling agent KH-792 was added. Under the condition of 80 °C, mechanically stirred for 2 hours. After the reaction, washed with deionized water, filtered and dried (110 °C) to obtain surface-treated hollow glass microspheres.

[0084] The surface-treated hollow glass microspheres and polyether ether ketone were mixed at a mass ratio of 30:7 and poured into a quartz mold. The mold was placed on a shaking device and shaken for 15 minutes. Then the mold was put into a muffle furnace and heated to 370 °C according to a preset sintering program (heating 8 °C per minute), held at 370 °C for 15 minutes, taken out the mold, and demolded after it cooled to room temperature to obtain a hollow glass microsphere / polyether ether ketone porous preform.

[0085] Mix epoxy resin and curing agent in a mass ratio of 3:1 and stir evenly to obtain an epoxy resin mixture.

[0086] Place the obtained porous preform in a silicone rubber mold, pour the epoxy resin mixture into the silicone rubber mold until it just submerges the porous preform. Place the entire silicone rubber mold in a small vacuum chamber, evacuate and maintain pressure for 20 min, and observe that there is no boiling phenomenon of the epoxy resin. Take out the preform of hollow glass microspheres filled with liquid epoxy resin together with the mold, heat it to 80 °C and keep it warm for 5 h for curing, and then cool it naturally and demold.

[0087] Example 5

[0088] A method for preparing a high-performance hollow glass microsphere / epoxy resin floating material, and the preparation steps are as follows:

[0089] Pour 900 mL of deionized water into a beaker, add 90 mL of hollow glass microspheres, stir at room temperature for 10 min, let stand for 2 h, and take the upper-layer hollow glass microspheres for suction filtration and drying.

[0090] Place 20 g of floated hollow glass microspheres in 200 mL of NaOH solution with a solution concentration of 0.75 mol / L, stir at 50 °C for 2 h, let stand for 30 min after stirring, wash the hollow glass microspheres with deionized water until neutral, and then perform suction filtration and drying to obtain hydroxylated hollow glass microspheres.

[0091] Place 10 g of hydroxylated hollow glass microspheres in a mixed solution of 300 mL of ethanol and deionized water mixed in a volume ratio of 1:3. Add 1 g of coupling agent KH-792. Under the condition of 80 °C, use mechanical stirring for 2 h. After the reaction, wash with deionized water, perform suction filtration and drying (110 °C) to obtain surface-treated hollow glass microspheres.

[0092] Mix the surface-treated hollow glass microspheres and polyether ether ketone in a mass ratio of 30:8 and pour them into a quartz mold. Place the mold on a shaking device and shake for 15 min, then put the mold into a muffle furnace and heat it to 370 °C according to a preset sintering program (heating 7 °C per minute), keep it warm at 370 °C for 20 min, take out the mold, and demold it after it cools to room temperature to obtain a hollow glass microsphere / polyether ether ketone porous preform.

[0093] Mix epoxy resin and curing agent in a mass ratio of 3:1 and stir evenly to obtain an epoxy resin mixture.

[0094] Place the obtained porous preform in a silicone rubber mold, pour the epoxy resin mixture into the silicone rubber mold until it just submerges the porous preform. Place the entire silicone rubber mold in a small vacuum chamber, evacuate and hold the pressure for 20 min, and observe that there is no boiling phenomenon of the epoxy resin. Take out the hollow glass microsphere preform filled with liquid epoxy resin together with the mold, heat it to 80 °C and keep it warm for 5 h for curing, then cool it naturally after curing and demold it.

[0095] Comparative Example 1 (omitting the hydroxylation and coupling coating steps):

[0096] Pour 900 mL of deionized water into a beaker, add 90 mL of hollow glass microspheres, stir at room temperature for 10 min, let it stand for 2 h, and take the upper-layer hollow glass microspheres for suction filtration and drying.

[0097] Mix the flotation-treated hollow glass microspheres and polyetheretherketone in a mass ratio of 30:4 and pour them into a quartz mold. Place the mold on a shaking device and shake for 15 min, then put the mold into a muffle furnace and heat it to 370 °C according to a preset sintering program (heating 7 °C per minute), keep it warm at 370 °C for 15 min, take out the mold, and demold it after it cools to room temperature to obtain a hollow glass microsphere / polyetheretherketone porous preform.

[0098] Mix epoxy resin and curing agent in a mass ratio of 3:1 and stir evenly to obtain an epoxy resin mixture.

[0099] Place the obtained porous preform in a silicone rubber mold, pour the epoxy resin mixture into the silicone rubber mold until it just submerges the porous preform. Place the entire silicone rubber mold in a small vacuum chamber, evacuate and hold the pressure for 20 min, and observe that there is no boiling phenomenon of the epoxy resin. Take out the hollow glass microsphere preform filled with liquid epoxy resin together with the mold, heat it to 80 °C and keep it warm for 5 h for curing, then cool it naturally after curing and demold it.

[0100] Comparative Example 2 (high-temperature sintering at 700 °C):

[0101] Pour 900 mL of deionized water into a beaker, add 90 mL of hollow glass microspheres, stir at room temperature for 10 min, let it stand for 2 h, and take the upper-layer hollow glass microspheres for suction filtration and drying.

[0102] Place 20 g of flotation-treated hollow glass microspheres in 200 mL of NaOH solution with a solution concentration of 0.75 mol / L, stir at 50 °C for 2 h, let it stand for 30 min after stirring, wash the hollow glass microspheres with deionized water until neutral, and then perform suction filtration and drying to obtain hydroxylated hollow glass microspheres.

[0103] Place 10 g of hydroxylated hollow glass microspheres into a mixed solution of 300 mL of ethanol and deionized water mixed at a volume ratio of 1:3. Add 1 g of coupling agent KH-792. Under the condition of 80 °C, use mechanical stirring for 2 h. After the reaction is completed, wash with deionized water, filter by suction and dry (110 °C) to obtain surface-treated hollow glass microspheres.

[0104] Place the surface-treated hollow glass microspheres into a quartz mold, and then put the mold into a muffle furnace for high-temperature sintering at 700 °C. After heat preservation for 15 min, take out the mold. After it cools to room temperature, demold to obtain a hollow glass microsphere block.

[0105] Mix epoxy resin and curing agent in a mass ratio of 3:1 and stir evenly to obtain an epoxy resin mixture.

[0106] Place the obtained hollow glass microsphere block into a silicone rubber mold, and pour the epoxy resin mixture into the silicone rubber mold to just submerge the hollow glass microsphere block. Place the entire silicone rubber mold in a small vacuum chamber. After vacuumizing and maintaining pressure for 20 min, it is observed that there is no boiling phenomenon of the epoxy resin. Take out the preform of hollow glass microspheres filled with liquid epoxy resin together with the mold, heat it to 80 °C and keep it warm for 5 h for curing. After curing, cool it naturally and demold to obtain a solid floating material.

[0107] Comparative Example 3 (replace polyetheretherketone with polypropylene):

[0108] Pour 900 mL of deionized water into a beaker, add 90 mL of hollow glass microspheres, stir at room temperature for 10 min, let it stand for 2 h, and take the upper-layer hollow glass microspheres for suction filtration and drying.

[0109] Place 20 g of flotated hollow glass microspheres into 200 mL of NaOH solution with a solution concentration of 0.75 mol / L, stir at 50 °C for 2 h, let it stand for 30 min after stirring, wash the hollow glass microspheres with deionized water until neutral, and then filter by suction and dry to obtain hydroxylated hollow glass microspheres.

[0110] Place 10 g of hydroxylated hollow glass microspheres into a mixed solution of 300 mL of ethanol and deionized water mixed at a volume ratio of 1:3. Add 1 g of coupling agent KH-792. Under the condition of 80 °C, use mechanical stirring for 2 h. After the reaction is completed, wash with deionized water, filter by suction and dry (110 °C) to obtain surface-treated hollow glass microspheres.

[0111] The hollow glass microspheres treated with a coupling agent and polypropylene were mixed at a mass ratio of 30:4 and then poured into a quartz mold. The mold was placed on a shaking device and shaken for 15 min. Then, the mold was put into a muffle furnace and heated to 170 °C according to a preset sintering program (heating at 7 °C per minute), and held at 170 °C for 15 min. The mold was taken out, and after it cooled to room temperature, it was demolded to obtain a hollow glass microsphere / polypropylene porous preform.

[0112] Epoxy resin and a curing agent were mixed at a mass ratio of 3:1 and stirred evenly to obtain an epoxy resin mixture.

[0113] The obtained porous preform was placed in a silicone rubber mold, and the epoxy resin mixture was poured into the silicone rubber mold to just submerge the porous preform. The entire silicone rubber mold was placed in a small vacuum chamber, evacuated and pressurized for 20 min, and no boiling phenomenon of the epoxy resin was observed. The hollow glass microsphere preform filled with liquid epoxy resin was taken out together with the mold, heated to 80 °C and held for 5 h for curing. After curing, it was naturally cooled and demolded.

[0114] Comparative Example 4 (omitting the coupling coating step):

[0115] 900 mL of deionized water was poured into a beaker, 90 mL of hollow glass microspheres was added, and stirred at room temperature for 10 min, then left standing for 2 h. The upper-layer hollow glass microspheres were taken and filtered and dried.

[0116] 20 g of the well-floated hollow glass microspheres were placed in 200 mL of NaOH solution with a solution concentration of 0.75 mol / L, stirred at 50 °C for 2 h, left standing for 30 min after stirring, washed with deionized water until neutral, and then filtered and dried to obtain hydroxylated hollow glass microspheres.

[0117] The hydroxylated hollow glass microspheres and polyetheretherketone were mixed at a mass ratio of 30:4 and then poured into a quartz mold. The mold was placed on a shaking device and shaken for 15 min. Then, the mold was put into a muffle furnace and heated to 370 °C according to a preset sintering program (heating at 7 °C per minute), and held at 370 °C for 15 min. The mold was taken out, and after it cooled to room temperature, it was demolded to obtain a hollow glass microsphere / polyetheretherketone porous preform.

[0118] Epoxy resin and a curing agent were mixed at a mass ratio of 3:1 and stirred evenly to obtain an epoxy resin mixture.

[0119] Place the obtained porous preform in a silicone rubber mold, pour the epoxy resin mixture into the silicone rubber mold until it just submerges the porous preform. Place the entire silicone rubber mold in a small vacuum chamber, evacuate and maintain pressure for 20 minutes, and observe that there is no boiling phenomenon of the epoxy resin. Take out the hollow glass microsphere preform filled with liquid epoxy resin together with the mold, heat it to 80 °C and keep it warm for 5 hours for curing, and then cool it naturally and demold after curing.

[0120] Comparative Example 5 (omitting the hydroxylation step):

[0121] Pour 900 mL of deionized water into a beaker, add 90 mL of hollow glass microspheres, stir at room temperature for 10 minutes, let it stand for 2 hours, and take the upper-layer hollow glass microspheres for suction filtration and drying.

[0122] Place 10 g of the flotation-treated hollow glass microspheres in a mixed solution of 300 mL of ethanol and deionized water mixed in a volume ratio of 1:3. Add 1 g of coupling agent KH-792. Under the condition of 80 °C, use mechanical stirring for 2 hours. After the reaction, wash with deionized water, filter and dry (at 110 °C) to obtain the hollow glass microspheres after coupling coating treatment.

[0123] Mix the hollow glass microspheres after coupling coating treatment and polyether ether ketone in a mass ratio of 30:4, pour them into a quartz mold, place the mold on a vibrating device and vibrate for 15 minutes, then put the mold into a muffle furnace and heat it to 370 °C according to the preset sintering program (heating 7 °C per minute), keep it warm at 370 °C for 15 minutes, take out the mold, and demold it after it cools to room temperature to obtain a hollow glass microsphere / polyether ether ketone porous preform.

[0124] Mix epoxy resin and curing agent in a mass ratio of 3:1 and stir evenly to obtain an epoxy resin mixture.

[0125] Place the obtained porous preform in a silicone rubber mold, pour the epoxy resin mixture into the silicone rubber mold until it just submerges the porous preform. Place the entire silicone rubber mold in a small vacuum chamber, evacuate and maintain pressure for 20 minutes, and observe that there is no boiling phenomenon of the epoxy resin. Take out the hollow glass microsphere preform filled with liquid epoxy resin together with the mold, heat it to 80 °C and keep it warm for 5 hours for curing, and then cool it naturally and demold after curing.

[0126] Comparative Example 6 (reducing the mass ratio of hollow glass microspheres to polyether ether ketone):

[0127] Pour 900 mL of deionized water into a beaker, add 90 mL of hollow glass microspheres, stir at room temperature for 10 minutes, let it stand for 2 hours, and take the upper-layer hollow glass microspheres for suction filtration and drying.

[0128] Put 20 g of well-floated hollow glass microspheres into 200 mL of NaOH solution with a concentration of 0.75 mol / L. Stir at 50 °C for 2 h. After stirring, let it stand for 30 min. Wash the hollow glass microspheres with deionized water until neutral, then filter and dry to obtain hydroxylated hollow glass microspheres.

[0129] Put 10 g of hydroxylated hollow glass microspheres into a mixed solution of 300 mL of ethanol and deionized water mixed by a volume ratio of 1:3. Add 1 g of coupling agent KH-792. Under the condition of 80 °C, use mechanical stirring for 2 h. After the reaction, wash with deionized water, filter and dry (at 110 °C) to obtain surface-treated hollow glass microspheres.

[0130] Mix the surface-treated hollow glass microspheres and polyether ether ketone by a mass ratio of 30:3 and pour them into a quartz mold. Place the mold on a vibrating device and vibrate for 15 min. Then put the mold into a muffle furnace and heat it to 370 °C according to a preset sintering program (heating 7 °C per minute). Keep it at 370 °C for 15 min. Take out the mold, wait for it to cool to room temperature and then demold to obtain a hollow glass microsphere / polyether ether ketone porous preform.

[0131] Mix epoxy resin and curing agent by a mass ratio of 3:1 and stir evenly to obtain an epoxy resin mixture.

[0132] Put the obtained porous preform into a silicone rubber mold, pour the epoxy resin mixture into the silicone rubber mold until it just submerges the porous preform. Place the whole silicone rubber mold in a small vacuum chamber, evacuate and maintain pressure for 20 min, and observe that there is no boiling phenomenon of the epoxy resin. Take out the hollow glass microsphere preform filled with liquid epoxy resin together with the mold, heat it to 80 °C and keep it warm for 5 h for curing. After curing, let it cool naturally and demold.

[0133] Comparative Example 7 (increasing the mass ratio of hollow glass microspheres to polyether ether ketone):

[0134] Pour 900 mL of deionized water into a beaker, add 90 mL of hollow glass microspheres, stir at room temperature for 10 min, let it stand for 2 h, and take the upper-layer hollow glass microspheres for filtration and drying.

[0135] Put 20 g of well-floated hollow glass microspheres into 200 mL of NaOH solution with a concentration of 0.75 mol / L. Stir at 50 °C for 2 h. After stirring, let it stand for 30 min. Wash the hollow glass microspheres with deionized water until neutral, then filter and dry to obtain hydroxylated hollow glass microspheres.

[0136] Place 10 g of hydroxylated hollow glass microspheres into a mixed solution of 300 mL of ethanol and deionized water mixed at a volume ratio of 1:3. Add 1 g of coupling agent KH-792. Under the condition of 80 °C, use mechanical stirring for 2 h. After the reaction is completed, wash with deionized water, filter by suction and dry (at 110 °C) to obtain surface-treated hollow glass microspheres.

[0137] Mix the surface-treated hollow glass microspheres and polyether ether ketone at a mass ratio of 30:15 and pour them into a quartz mold. Place the mold on a shaking device and shake for 15 min. Then put the mold into a muffle furnace and heat it to 370 °C according to a preset sintering program (heating up 7 °C per minute), keep it at 370 °C for 15 min, take out the mold, and demold after it cools to room temperature to obtain a hollow glass microsphere / polyether ether ketone porous preform.

[0138] Mix epoxy resin and a curing agent at a mass ratio of 3:1 and stir evenly to obtain an epoxy resin mixture.

[0139] Place the obtained porous preform into a silicone rubber mold, pour the epoxy resin mixture into the silicone rubber mold to just submerge the porous preform. Place the entire silicone rubber mold in a small vacuum chamber, evacuate and maintain pressure for 20 min, and observe that there is no boiling phenomenon of the epoxy resin. Take out the hollow glass microsphere preform filled with liquid epoxy resin together with the mold, heat it to 80 °C and keep it warm for 5 h for curing, and after curing, let it cool naturally and demold.

[0140] Comparative Example 8 (omitting the preform preparation step):

[0141] Pour 900 mL of deionized water into a beaker, add 90 mL of hollow glass microspheres, stir at room temperature for 10 min, let it stand for 2 h, take the upper-layer hollow glass microspheres, filter by suction and dry.

[0142] Place 20 g of well-floated hollow glass microspheres into 200 mL of NaOH solution with a solution concentration of 0.75 mol / L, stir at 50 °C for 2 h, let it stand for 30 min after stirring, wash the hollow glass microspheres with deionized water until neutral, and then filter by suction and dry to obtain hydroxylated hollow glass microspheres.

[0143] Place 10 g of hydroxylated hollow glass microspheres into a mixed solution of 300 mL of ethanol and deionized water mixed at a volume ratio of 1:3. Add 1 g of coupling agent KH-792. Under the condition of 80 °C, use mechanical stirring for 2 h. After the reaction is completed, wash with deionized water, filter by suction and dry (at 110 °C) to obtain surface-treated hollow glass microspheres.

[0144] Mix epoxy resin and a curing agent at a mass ratio of 3:1 and stir evenly to obtain an epoxy resin mixture.

[0145] After uniformly stirring the epoxy resin mixture and the surface-treated hollow glass microspheres, perform vacuum degassing treatment. Then pour the slurry into a mold, heat it to 80 °C, keep it warm for 5 h for curing, and after curing, let it cool naturally and demold.

[0146] Detection:

[0147] Detect the compressive strength, density, water absorption rate, etc. of the hollow glass microsphere / epoxy resin floating body materials prepared in the above Examples 1-5 and Comparative Examples 1-8. The results are shown in Table 1 below:

[0148] Table 1 Performance parameters of hollow glass microsphere / epoxy resin floating body materials

[0149]

[0150]

[0151] Among them, the determination of compressive strength and stress-strain curve: The compression test of the floating body material is tested according to the standard of GB / T 1041-1992 to obtain the compressive strength and stress-strain curve. The test sample size is 10 mm × 10 mm × 20 mm. The compression test is carried out on an electronic universal testing machine (Instron5569). The loading rate of the indenter is 0.5 mm / min. Record the compression stress-strain curve of the compression sample, and calculate the compression elastic modulus according to the compression stress-strain curve of the sample. The calculation formula for the compressive strength of the composite material is:

[0152] σc = N / S (1)

[0153] In the formula, σc——compressive strength, MPa;

[0154] N——the load borne by the sample, N; S——the cross-sectional area of the sample, mm 2 .

[0155] Testing method for open porosity of porous preform:

[0156] Test the density and open porosity according to GB / T 1966-1996 "Test Methods for Apparent Porosity and Bulk Density of Porous Ceramics". First, clean the surface of the sample, place it in a 110 °C blast drying oven and dry it for 2 h, and weigh the mass as m1 using a high-precision analytical balance (accuracy 0.1 mg). After the sample is put into a container filled with deionized water and boiled for 2 h, stop heating, cool it to room temperature, wipe off the excess water on the surface of the sample, and then weigh the mass in the air as m2; weigh the mass when immersed in water as m3. The calculation formulas for the density and porosity of HGM porous ceramics are as follows:

[0157]

[0158] At least 5 specimens shall be tested for each group, and the average value shall be taken and the error limit shall be calculated.

[0159] Test method for water absorption rate of composite materials:

[0160] The water absorption rate of the material is tested in accordance with GB / T 1034-2008 "Determination of Water Absorption of Materials". The specimen size is Φ50×3mm, and the average value is taken from three specimens tested in each group experiment. First, the specimens are dried in an oven at 50°C for 24h, then cooled to room temperature in a desiccator, and the mass is weighed and recorded as m1. Then the specimens are immersed in deionized water or simulated seawater solution at room temperature and 50°C. The specimens are taken out at regular intervals. After the samples are removed, the surface of the specimens is wiped with filter paper and quickly weighed, and the mass is recorded as m2. The calculation formula for the water absorption rate w of the composite material is:

[0161]

[0162] The open pore rate of the porous preforms prepared in Examples 1-5 is about 35%. The microsphere filling rate = (100% - open pore rate) * ((HGM filling mass / HGM true density) / ((HGM filling mass / HGM true density) + (PEEK filling mass / PEEK density)). The true density of the HGM used in this patent is 0.6 g / cm 3 , and the density of PEEK is 1.3 g / cm 3 .

[0163] In Comparative Example 1, hollow glass microspheres without modified hydroxyl groups and coupling agents were used to prepare preforms with PEEK, and then composites were prepared with epoxy resin, and their strength decreased significantly. The interfacial bonding force between the hollow glass microspheres without modified hydroxyl groups and coupling agents and epoxy resin is poor during curing, thus affecting the strength and elastic modulus. Moreover, hydroxyl groups and silane coupling agents enhance the bonding performance between the hollow glass microspheres and PEEK. When forming the preform, the bonding between the hollow glass microspheres without modified hydroxyl groups and coupling agents and PEEK is not tight (observed with the naked eye), that is, some hollow glass microspheres are not successfully bonded in the preform and are prone to detachment from the preform, resulting in a decrease in the microsphere filling rate.

[0164] In Comparative Example 2, the microspheres were sintered into preforms at 700°C. The microspheres were significantly softened and the shape also changed. Finally, the strength and elastic modulus of the composite material also decreased.

[0165] In Comparative Example 3, polypropylene resin was used, and finally the strength and elastic modulus of the composite material decreased.

[0166] In Comparative Example 4, without coupling agent modification, it directly affects the interfacial bonding force between the hollow glass microspheres and PEEK and epoxy resin. Finally, the strength and elastic modulus of the floating body material decreased.

[0167] In Comparative Example 5, without hydroxyl modification, it is not conducive to the modification by the coupling agent. The attachment state of the coupling agent is inferior to that in Examples 1-5, affecting the interfacial bonding force between the hollow glass microspheres and polyether ether ketone and epoxy resin. Eventually, the strength and elastic modulus of the floating body material decrease.

[0168] In Comparative Example 6, the mass ratio of the surface-treated hollow glass microspheres to polyether ether ketone is 30:3. The addition amount of polyether ether ketone is too low to achieve the molding of the preform, so that the final composite material cannot be molded. As shown in b in Figure 3 , it can be clearly seen that there is a phenomenon of powder shedding.

[0169] In Comparative Example 7, the mass ratio of the hollow glass microspheres to polyether ether ketone is 30:15. Since the amount of polyether ether ketone used is too much, replacing the position of the hollow glass microspheres has a great impact on the filling amount of the hollow glass microspheres.

[0170] In Comparative Example 8, because the stirring casting method is adopted, irregular bubbles will be generated inside the composite material, and finally the strength of the composite material will decrease significantly. Macroscopic cracks appear in the prepared composite material after the compressive strength test, as shown in Figure 4 .

[0171] Figure 1 is the preparation flow chart of the floating body material of the present invention; Figure 2 are the macroscopic and microscopic morphologies of the HGM porous preform (Example 1), a, macroscopic morphology, b, microscopic morphology. The HGM porous preforms prepared in Examples 2-5 are similar to Figure 2 and all form a tight combination of hollow glass microspheres and PEEK, and the hollow glass microspheres are evenly distributed in the porous preform; Figure 3 are the successfully or unsuccessfully prepared preforms: (a) Example 1, (b) Comparative Example 6; Figure 4 is the compression diagram of the floating body material. Macroscopic cracks appear in the floating body material after the compressive strength test (Comparative Example 8).

[0172] Figure 5 is the stress-strain curve of the epoxy resin used to prepare the floating body material (only mixing the epoxy resin and the curing agent in a mass ratio of 3:1 to prepare an epoxy resin block, without adding hollow glass microspheres or preforms, and measuring its compressive strength to obtain the stress-strain curve). The calculation formula of the compressive strength is shown in Equation (1).

[0173] Figure 6 The stress-strain curve diagrams of the porous preform / epoxy resin composite materials prepared by mixing different ratios of microspheres and polyether ether ketone in Examples 1-5 show that the compressive properties of the porous preform / epoxy resin composite floating body materials in Examples 1-5 are all better.

[0174] Figure 7 The microscopic structure of the floating body material, Figure 7(a) corresponds to Example 1 (no bubbles in the microstructure), Figure 7 (b) in the figure corresponds to Example 8 (air bubbles in the microstructure). The composite materials prepared in Examples 2-5 are similar to those in Example 1, and there are no air bubbles in the microstructure. Only the composite materials prepared by the stirring casting method will produce air bubbles. Figure 7 As shown in (b); Comparative Example 1 is Figure 7 As shown in (c) of Figure 7 Compared with (a), about half of the microbeads were not firmly bonded and fell off; microbeads also fell off in Comparative Examples 4 and 5.

[0175] Figure 8 The longitudinal cracks that appeared inside the sample under the ultimate compressive stress of 85MPa along the pressure direction correspond to Example 1. The hollow glass microspheres are tightly bonded to the epoxy resin matrix and are longitudinally fractured from the middle of the hollow glass microspheres. This shows that the interface bonding is strong and the load transfer is effective. However, the brittleness and strength limitation of the hollow glass microspheres cause the microspheres themselves to break when subjected to a large external force. This fracture mode reflects the good bonding and certain toughness of the composite material. The floating materials prepared in Examples 2-5 are similar to Figure 8 Close-up, longitudinal cracks appearing inside the sample along the direction of pressure under compressive stress.

[0176] Figure 9 Flow chart of preparation of hollow glass microsphere / polyetheretherketone porous preform;

[0177] Figure 10 The particle size distribution diagram of hollow glass microspheres shows the particle size distribution of the hollow glass microsphere raw materials used.

[0178] It should be understood that the above embodiments do not limit the present invention in any form, and any technical solutions obtained by equivalent replacement or equivalent transformation shall fall within the protection scope of the present invention.

Claims

1. A method for preparing high-performance hollow glass microsphere / epoxy resin floating material, characterized in that: The preparation process is as follows: (1) hydroxylating and coupling agent coating the hollow glass microspheres to obtain surface-treated hollow glass microspheres; (2) mixing the surface-treated hollow glass microspheres and polyetheretherketone in a uniform proportion, placing them into a mold and sintering them in a muffle furnace, wherein the sintering process is as follows: heating to 370°C-380°C at a heating rate of 5-10°C / min and keeping the temperature for 15-20min, cooling, and demolding to obtain a porous preform; wherein the mass ratio of the surface-treated hollow glass microspheres to the polyetheretherketone is 30:4-8; (3) mixing the epoxy resin and the curing agent in proportion and stirring evenly to obtain an epoxy resin mixed solution; (4) placing the porous preform obtained in step (2) in a cavity mold, injecting the epoxy resin mixture obtained in step (3), evacuating and maintaining pressure for a period of time, heating and curing, cooling, and demolding; Step (4) is specifically as follows: placing the porous preform obtained in step (2) in a mold, pouring the epoxy resin mixture obtained in step (3) into the mold, and allowing the epoxy resin mixture to submerge the porous preform; placing the entire mold in a vacuum box, evacuating and maintaining pressure until the epoxy resin stops boiling, and a hollow glass microsphere preform filled with liquid epoxy resin is formed in the mold; taking out the hollow glass microsphere preform filled with liquid epoxy resin together with the mold, heating to 70-90°C and keeping the temperature for 4-6 hours, cooling after solidification, and demolding to obtain the final floating material.

2. The method for preparing a high-performance hollow glass microsphere / epoxy resin floating material according to claim 1, characterized in that: Step (2) is specifically as follows: mixing the surface-treated hollow glass microspheres with the polyetheretherketone powder and pouring the mixture into a mold, placing the mold containing the surface-treated hollow glass microspheres and the polyetheretherketone powder on an oscillating device, and oscillating the mold for a period of time so that the polyetheretherketone powder is evenly mixed on the surface of the hollow glass microspheres and is sufficiently densely stacked; then, placing the mold containing the densely stacked polyetheretherketone powder and the hollow glass microspheres in a muffle furnace, gradually heating to 370°C-380°C, keeping the temperature for 15-20 minutes, cooling to room temperature, and demolding to obtain a hollow glass microsphere / polyetheretherketone porous preform.

3. The method for preparing high-performance hollow glass microsphere / epoxy resin floating material according to claim 1, characterized in that: In step (1), before the hollow glass microspheres are subjected to hydroxylation and coupling agent coating treatment, the hollow glass microspheres are subjected to flotation treatment; in the flotation treatment, the operation steps are: mixing the hollow glass microspheres with pure water in proportion, stirring at a certain speed, taking the upper layer of microspheres after standing for a certain time, and drying to obtain the hollow glass microspheres after flotation; in the flotation treatment, when the hollow glass microspheres are soaked in pure water, the volume ratio of the hollow glass microspheres to water is 1:8-12; in the flotation treatment, the stirring time is 5-15 minutes, and the stirring needs to be allowed to stand for 1-3 hours.

4. The method for preparing a high-performance hollow glass microsphere / epoxy resin floating material according to claim 1, characterized in that: In step (1), the hollow glass microspheres are hydroxylated with a 0.6-1.0 mol / L NaOH solution, and the solution is stirred during the hydroxylation. During the hydroxylation, the temperature is 40-60°C, the treatment time is 1.5-2.5h, and the stirring rate is 300-500rpm. The mass volume ratio of the hollow glass microspheres to the NaOH solution is 1g: (8-12)mL.

5. The method for preparing high-performance hollow glass microsphere / epoxy resin floating material according to claim 1, characterized in that: During the coupling agent coating process, the hollow glass microspheres after hydroxylation treatment are placed in an ethanol solution, which is a mixture of anhydrous ethanol and deionized water in a volume ratio of 1:3, and then a high-temperature resistant silane coupling agent KH-792 is added, and stirred at 70-90 ° C for 1.5-2.5 h; the hollow glass microspheres after surface treatment are taken, washed, and dried at 110-120 ° C to complete the curing of the coupling agent and the formation of chemical bonds.

6. The method for preparing a high-performance hollow glass microsphere / epoxy resin floating material according to claim 4, characterized in that: In the coupling agent coating process, the coupling agent used is a high temperature resistant silane coupling agent KH-792. The presence of diamino groups increases the reaction opportunities and improves the interface bonding strength. The mass ratio of the coupling agent to the hollow glass microspheres after hydroxylation is 1:7-13; the mass volume ratio of the hollow glass microspheres after hydroxylation to the ethanol solution is 1g:(20-40)mL.

7. The method for preparing high-performance hollow glass microsphere / epoxy resin floating material according to claim 2, characterized in that: The mold for containing the surface-treated hollow glass microspheres and polyetheretherketone in step (2) is a quartz mold.

8. The method for preparing a high-performance hollow glass microsphere / epoxy resin floating material according to claim 1, characterized in that: In step (3), the mass ratio of epoxy resin to curing agent is 2.5-3.5:1; the epoxy resin is liquid epoxy resin.

9. The method for preparing a high-performance hollow glass microsphere / epoxy resin floating material according to claim 1, characterized in that: In step (3), the epoxy resin is E-51 epoxy resin, and the curing agent is amine curing agent HS-273M.

Images