High-strength and high-durability composite foam and preparation method thereof

Abstract

The invention discloses high-strength and high-durability composite foam and a preparation method thereof. The composite foam is obtained by mixing and molding raw materials including resin, glass hollow microspheres and magnetic metal hollow microspheres, wherein the magnetic metal hollow microsphere is of a core-shell structure, the core is a cavity, and the shell is composed of a glass ball shell layer, a magnetic metal ball shell layer wrapping the glass ball shell layer and a magnetic metal oxide ball shell layer wrapping the magnetic metal ball shell layer; wherein the magnetic metal spherical shell layer is made of magnetic metal, and the magnetic metal oxide spherical shell layer is made of oxide of the magnetic metal; the volume ratio of the glass hollow microspheres to the magnetic metal hollow microspheres is (9: 1)-(2: 1). The composite foam material disclosed by the invention not only has relatively high mechanical strength and low density, but also has relatively high performance stability.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and more particularly to a high-strength and high-durability composite foam and a preparation method thereof. Background Art

[0002] The continuous development of modern industry is driving a growing demand for high-performance materials. Syntactic foams have attracted significant attention due to their unique low density and functional properties. Compared to traditional foam materials, syntactic foams constructed with preformed hollow microspheres as lightweight fillers offer distinct advantages, providing a new approach to solving numerous practical problems. Firstly, similar to foam materials, the combination of preformed hollow microspheres with a polymer matrix significantly reduces the overall density of the material. This gives these syntactic foams enormous potential for application in weight-critical applications such as aerospace and marine applications. For example, in aviation, the use of these low-density syntactic foams can reduce aircraft weight, lower fuel consumption, and improve flight efficiency and range. Secondly, they possess high strength and rigidity. Despite their low density, through rational design and preparation, these materials exhibit exceptional strength and rigidity when subjected to external forces. The excellent integration of the hollow microspheres with the matrix material, as well as the synergistic effect between the microspheres, enables the material to effectively distribute stress and improve load-bearing capacity. This holds significant potential in structural and protective materials, providing reliable protection for equipment and personnel. Furthermore, this composite foam material exhibits excellent thermal and sound insulation properties. The internal space within the hollow microspheres and the porous structure of the material effectively block the transmission of heat and sound, offering broad application prospects in fields such as construction and transportation. Furthermore, the material is highly designable. The type, size, and content of the hollow microspheres, as well as the properties of the matrix material, can be adjusted to suit specific application requirements, enabling precise control of material properties.

[0003] Given the ultra-low density of this type of preformed hollow microsphere composite foam material, it has unique application advantages in the field of providing buoyancy in deep-sea environments. For applications that provide buoyancy, low density is a must rather than an optimization solution. According to Archimedes' principle, the effective buoyancy of a material is determined by the volume of water it displaces and its own weight. Therefore, it is necessary to reduce its own weight through lightweight design, while maintaining volume stability under high water pressure through high rigidity and high strength design. However, in the deep-sea environment, moisture will diffuse into the interior of the composite foam through the interface and cavity, resulting in a decrease in the external pressure energy that the material can withstand and an increase in its own weight, thereby causing a decrease in service performance. On the other hand, for other application scenarios other than deep-sea environments, composite foam materials may also undergo structural and composition changes due to the influence of water vapor in the environment, resulting in performance degradation. It is worth mentioning that the structural and performance degradation caused by the above-mentioned water absorption or moisture absorption will be further exacerbated under water pressure (deep-sea applications) or high temperature, accelerating performance degradation.

[0004] Therefore, while current hollow microsphere composite foam materials can achieve a combination of low density and high strength, they still face some durability issues. To address these issues, further in-depth research is needed to develop more environmentally resistant material systems and improve their reliability and service life in water and humid environments. Summary of the Invention

[0005] Based on the above problems, the object of the present invention is to provide a high-strength, high-durability composite foam and a preparation method thereof.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] In one aspect, the present invention provides a high-strength, high-durability composite foam, which is obtained by mixing raw materials including resin, glass hollow microspheres, and magnetic metal hollow microspheres and then molding them; wherein,

[0008] The magnetic metal hollow microspheres are of a core-shell structure, wherein the core is a cavity and the shell is composed of a glass shell layer, a magnetic metal shell layer covering the glass shell layer, and a magnetic metal oxide shell layer covering the magnetic metal shell layer.

[0009] Wherein, the material of the magnetic metal spherical shell layer is magnetic metal, and the material of the magnetic metal oxide spherical shell layer is the oxide of the magnetic metal;

[0010] The volume ratio of the glass hollow microspheres to the magnetic metal hollow microspheres is 9:1-2:1.

[0011] Furthermore, the density of the composite foam is 0.5-0.9 g / cm 3 ,

[0012] In the composite foam, the density of the glass hollow microspheres is 0.15-0.6 g / cm 3 The density of magnetic metal hollow microspheres is ±0.05 g / cm2 of the density of glass hollow microspheres. 3 within the range.

[0013] Furthermore, in the composite foam, the total content of the glass hollow microspheres and the magnetic metal hollow microspheres is 45-65% by volume.

[0014] Furthermore, the magnetic metal hollow microspheres contain, by mass percentage, 60-86% of glass hollow microspheres, 3-18% of magnetic metal spherical shells, and 5-25% of magnetic metal oxide spherical shells.

[0015] Furthermore, the magnetic metal is selected from one or more of nickel, cobalt and iron, and the corresponding magnetic metal oxides are nickel oxide, cobaltous oxide, ferric oxide and the like.

[0016] Furthermore, the resin is selected from one or more of epoxy resin, unsaturated polyester resin, phenolic resin, polyurethane resin and polystyrene.

[0017] Furthermore, the preparation of the magnetic metal hollow microspheres includes the following steps:

[0018] The glass hollow microspheres are sequentially placed in a stannous chloride aqueous solution and a palladium chloride aqueous solution, and stirred at 50-55° C. for 15-25 minutes, filtered, and dried to obtain surface-activated glass hollow microspheres.

[0019] placing the surface-activated glass hollow microspheres in a chemical reduction treatment solution containing the ion source salt of the magnetic metal, stirring and reacting in a water bath at 55-85° C. for 20-30 minutes to form a magnetic metal shell covering the glass hollow microspheres on the surface of the glass hollow microspheres;

[0020] The surface of the magnetic metal spherical shell is oxidized in an air atmosphere to obtain the magnetic metal hollow microspheres.

[0021] Furthermore, the composition of the stannous chloride aqueous solution comprises:

[0022] Water, and relative to water,

[0023] Stannous chloride with a concentration of 50-60 g / L and concentrated hydrochloric acid with a concentration of 10-15 ml / L.

[0024] Furthermore, the composition of the palladium chloride aqueous solution comprises:

[0025] Water, and relative to water,

[0026] The concentration of palladium chloride is 0.5-0.6g / L and the concentration of concentrated hydrochloric acid is 10-15ml / L.

[0027] Furthermore, the concentration of the glass hollow microspheres in the stannous chloride aqueous solution and the palladium chloride aqueous solution is 20-50 g / L.

[0028] Furthermore, the chemical reduction treatment solution comprises:

[0029] Water, and relative to water,

[0030] The ion source salt of the magnetic metal with a concentration of 20-50 g / L, the stabilizer with a concentration of 30-100 g / L, the reducing agent with a concentration of 80-150 g / L, and

[0031] A pH regulator is used to adjust the pH of the chemical reduction treatment solution to 9.5-11.

[0032] Furthermore, the concentration of the surface-activated glass hollow microspheres in the chemical reduction treatment solution is 15-50 g / L.

[0033] Furthermore, the ion source salt of the magnetic metal may be a sulfate or chloride of the magnetic metal, for example, cobalt sulfate, ferrous ammonium sulfate, nickel sulfate, etc.

[0034] Furthermore, the stabilizer is selected from ammonium sulfate and / or potassium sodium tartrate.

[0035] Illustratively, in the chemical reduction treatment solution, the concentration of the stabilizer includes but is not limited to 30-80 g / L, 30-50 g / L, 35-50 g / L, 35-45 g / L, 35-40 g / L, 40-50 g / L, 40-50 g / L, 40-45 g / L, etc.

[0036] Furthermore, the reducing agent is selected from sodium hypophosphite and the like.

[0037] Furthermore, the pH regulator is selected from inorganic bases, such as ammonia water.

[0038] Furthermore, the oxidation temperature is 350-550° C. and the time is 5-15 minutes.

[0039] In a second aspect, the present invention provides a method for preparing the composite foam as described above, comprising the following steps:

[0040] The glass hollow microspheres, magnetic metal hollow microspheres and resin are mixed evenly and placed in a mold. After homogenization by vibration and vacuum degassing, the mixture is solidified and molded, and demolded to obtain the composite foam.

[0041] The composite foam can be used as a lightweight, high-strength composite material, such as an underwater buoyancy material or a lightweight structural material. The combination of the two microspheres is intended to block the passage of water vapor and improve service stability in humid, hot and water environments.

[0042] The beneficial effects of the present invention are as follows:

[0043] The composite foam provided by the present invention achieves low density through the use of hollow microspheres filled in a large proportion, and achieves high strength through the support of the hollow microsphere shells combined with the molding effect of the resin matrix. The composite foam structure is composed of two different hollow microspheres and a high-strength resin to reduce overall costs. The magnetic metal hollow microspheres with an oxide-metal-glass three-layer structure can be used to block the path of water vapor transmission into the composite foam, and the glass hollow microspheres can reduce the density and cost of the composite foam. The composite foam material of the present invention not only has high mechanical strength and low density, but also has high performance stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0045] Figure 1 A schematic diagram showing the structure of an exemplary high-strength, high-durability composite foam according to the present invention is shown. DETAILED DESCRIPTION

[0046] In order to more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments and accompanying drawings. Similar components in the accompanying drawings are represented by the same reference numerals. It should be understood by those skilled in the art that the following detailed description is illustrative rather than restrictive and should not be used to limit the scope of protection of the present invention.

[0047] The technical solution of the present invention is described below with reference to some specific embodiments. In the following embodiments, the performance test method is as follows:

[0048] Test thermal conductivity by thermal conductivity meter;

[0049] The compressive strength of the microspheres was evaluated by a water pressure confining pressure test (the pressure at which the volume survival rate was 80%);

[0050] The uniaxial compressive strength of the composite foam material before and after hydrothermal treatment (temperature 40° C., humidity 93%, treatment time 24 h) was tested by a mechanical testing machine.

[0051] Example 1

[0052] The high-strength and high-durability composite foam based on preformed hollow microspheres is shown in the schematic diagram of its structure. Figure 1 As shown, the preparation method comprises the following steps:

[0053] Preparation of hollow microspheres 2 (magnetic metal hollow microspheres):

[0054] 1) Glass hollow microspheres (density 0.17 g / cm 3 , with an internal cavity diameter of 54 microns) was placed in a stannous chloride aqueous solution (the aqueous solution contained water, stannous chloride with a concentration of 60 g / L, and 15 ml / L of concentrated hydrochloric acid) at a ratio of 20 g / L, and stirred at 50° C. for 20 min; then placed in a palladium chloride aqueous solution (the aqueous solution contained water, 0.6 g / L of palladium chloride, and 15 ml / L of concentrated hydrochloric acid), and stirred at 50° C. for 20 min; the treated microspheres were filtered and dried to obtain intermediate hollow microspheres A;

[0055] 2) The intermediate hollow microspheres A obtained in step 1) were added at an amount of 48 g / L to a treatment solution containing 24 g / L cobalt sulfate, 25 g / L ammonium ferrous sulfate, 50 g / L sodium hypophosphite, 40 g / L ammonium sulfate, 100 g / L potassium sodium tartrate, and aqueous ammonia (the amount of aqueous ammonia added was such that the pH of the treatment solution was approximately 10.5), stirred in a water bath at 75° C. for 25 min, filtered, and dried to obtain intermediate hollow microspheres B;

[0056] 3) The intermediate hollow microspheres B obtained in step 2) were treated in a flowing air atmosphere at 350° C. for 10 min to obtain hollow microspheres 2.

[0057] The structure of the hollow microsphere 2 is: a hollow core, a glass shell layer from the inside out, a magnetic metal shell layer covering the glass shell layer, and a magnetic metal oxide shell layer covering the magnetic metal shell layer.

[0058] The mass fractions of glass, magnetic metal (cobalt-iron alloy), and magnetic metal oxide (cobaltous oxide and ferric oxide) in the hollow microspheres 2 are 85.9%, 8.6%, and 5.5%, respectively.

[0059] Preparation of composite foam:

[0060] 4) Hollow microsphere 1 (glass hollow microsphere, density 0.18g / cm 3 , the internal cavity diameter is 52 microns) and hollow microspheres 2 are mixed in a volume ratio of 2:1, and then mixed with TDE-85 epoxy resin + anhydride curing agent two-component epoxy resin (the volume ratio of the sum of hollow microspheres 1 and hollow microspheres 2 to resin is 63:37). After mixing, it is loaded into a mold (casting method), vibrated and homogenized on a vibration table, and vacuum-defoamed in a vacuum box. Then, it is successively kept at 55°C for 8h, 80°C for 3h, 120°C for 3h, and 160°C for 4h for curing and molding. After molding, the mold is demolded, and the uneven skin area is removed by turning to obtain the composite foam. In the composite foam, the total volume percentage of the hollow microspheres is 65%.

[0061] The density of the high-strength, high-durability composite foam is 0.53 g / cm 3 The uniaxial compressive strength is 49.2 MPa. After wet heat treatment, the uniaxial compressive strength decreases by 4.3%. The thermal conductivity is 0.167 W / m·K.

[0062] Example 2

[0063] A high-strength, high-durability composite foam based on preformed hollow microspheres is prepared by a method comprising the following steps:

[0064] Preparation of hollow microspheres 2 (magnetic metal hollow microspheres):

[0065] 1) Glass hollow microspheres (density 0.25g / cm 3 , with an internal cavity diameter of 46 microns) was placed in a stannous chloride aqueous solution (the aqueous solution contained water, stannous chloride with a concentration of 60 g / L, and 15 ml / L of concentrated hydrochloric acid) at a ratio of 20 g / L, and stirred at 50° C. for 25 min; then placed in a palladium chloride aqueous solution (the aqueous solution contained water, 0.6 g / L of palladium chloride, and 15 ml / L of concentrated hydrochloric acid), and stirred at 50° C. for 20 min; the treated microspheres were filtered and dried to obtain intermediate hollow microspheres A;

[0066] 2) adding 22.1 g / L of the intermediate hollow microspheres A obtained in step 1) to a treatment solution containing 21 g / L nickel sulfate, 22 g / L ammonium ferrous sulfate, 45 g / L sodium hypophosphite, 40 g / L ammonium sulfate, 90 g / L potassium sodium tartrate, and aqueous ammonia (the amount of aqueous ammonia added was such that the pH of the treatment solution was approximately 11), stirring in an 80° C. water bath for 30 min, filtering, and drying to obtain intermediate hollow microspheres B;

[0067] 3) The intermediate hollow microspheres B obtained in step 2) were treated in a flowing air atmosphere at 450° C. for 9 min to obtain hollow microspheres 2.

[0068] The structure of the hollow microsphere 2 is: a hollow core, a glass shell layer from the inside out, a magnetic metal shell layer covering the glass shell layer, and a magnetic metal oxide shell layer covering the magnetic metal shell layer.

[0069] The mass fractions of glass, magnetic metal (nickel-iron alloy), and magnetic metal oxide (nickel oxide and ferrous oxide) in the hollow microspheres 2 are 75.4%, 15.1%, and 9.5%, respectively.

[0070] Preparation of composite foam:

[0071] 4) Hollow microsphere 1 (glass hollow microsphere, density 0.29g / cm 3, with an internal cavity diameter of 45 microns) and hollow microspheres 2 in a volume ratio of 3:1, and then mixed with E-44 epoxy resin (the volume ratio of the sum of hollow microspheres 1 and hollow microspheres 2 to the resin is 3:2), and after mixing, it is loaded into a mold (casting method), vibrated and homogenized on a vibration table, and vacuum-defoamed in a vacuum box. Then, it is cured and molded by keeping it warm at 55°C for 8h, 80°C for 3h, 120°C for 3h, and 160°C for 4h. After molding, it is demolded and the uneven surface area is removed by turning to obtain the composite foam. In the composite foam, the total volume percentage of the hollow microspheres is 62%.

[0072] The density of the high-strength, high-durability composite foam is 0.64 g / cm 3 The uniaxial compressive strength is 72.5 MPa. After wet heat treatment, the uniaxial compressive strength decreases by 4.9%. The thermal conductivity is 0.176 W / m·K.

[0073] Example 3

[0074] A high-strength, high-durability composite foam based on preformed hollow microspheres is prepared by a method comprising the following steps:

[0075] Preparation of hollow microspheres 2 (magnetic metal hollow microspheres):

[0076] 1) Glass hollow microspheres (density 0.3g / cm 3 , with an internal cavity diameter of 44 microns) was placed in a stannous chloride aqueous solution (the aqueous solution contained water, stannous chloride with a concentration of 60 g / L, and 15 ml / L of concentrated hydrochloric acid) at a ratio of 30 g / L, and stirred at 50° C. for 15 minutes; then placed in a palladium chloride aqueous solution (the aqueous solution contained water, 0.6 g / L of palladium chloride, and 15 ml / L of concentrated hydrochloric acid), and stirred at 50° C. for 20 minutes; the treated microspheres were filtered and dried to obtain intermediate hollow microspheres A;

[0077] 2) adding 20 g / L of the intermediate hollow microspheres A obtained in step 1) to a treatment solution containing 21 g / L cobalt sulfate, 22 g / L nickel sulfate, 50 g / L sodium hypophosphite, 40 g / L ammonium sulfate, 80 g / L potassium sodium tartrate, and aqueous ammonia (the amount of aqueous ammonia added is such that the pH of the treatment solution is approximately 10), stirring in a water bath at 65° C. for 20 min, filtering, and drying to obtain intermediate hollow microspheres B;

[0078] 3) The intermediate hollow microspheres B obtained in step 2) were treated in a flowing air atmosphere at 450° C. for 15 min to obtain hollow microspheres 2.

[0079] The structure of the hollow microsphere 2 is: a hollow core, a glass shell layer from the inside out, a magnetic metal shell layer covering the glass shell layer, and a magnetic metal oxide shell layer covering the magnetic metal shell layer.

[0080] The mass fractions of glass, magnetic metal (nickel-cobalt alloy), and magnetic metal oxide (nickel oxide and cobaltous oxide) in the hollow microspheres 2 are 69.4%, 17.4%, and 13.2%, respectively.

[0081] Preparation of composite foam:

[0082] 4) Hollow microsphere 1 (glass hollow microsphere, density 0.41g / cm 3 , with an internal cavity diameter of 43 microns) and hollow microspheres 2 in a volume ratio of 4:1, and then mixed with an epoxy resin mixed with E-44 and TDE-85 in a mass ratio of 1:2 (the volume ratio of the sum of hollow microspheres 1 and hollow microspheres 2 to the resin is 29:21), and after mixing, it is loaded into a mold (casting method), vibrated and homogenized on a vibration table, and vacuum-defoamed in a vacuum box. Then, it is successively kept warm at 70°C for 5 hours, 120°C for 4 hours, and 160°C for 4 hours for curing and molding. After molding, the mold is demolded, and the uneven surface area is removed by turning to obtain the composite foam, in which the total volume percentage of the hollow microspheres is 60%.

[0083] The density of the high-strength, high-durability composite foam is 0.73 g / cm 3 The uniaxial compressive strength is 95.8 MPa. After heat treatment, the uniaxial compressive strength decreases by 5.8%. The thermal conductivity is 0.185 W / m·K.

[0084] Example 4

[0085] A high-strength, high-durability composite foam based on preformed hollow microspheres is prepared by a method comprising the following steps:

[0086] Preparation of hollow microspheres 2 (magnetic metal hollow microspheres):

[0087] 1) Glass hollow microspheres (density 0.37 g / cm 3 , with an internal cavity diameter of 45 microns) was placed in a stannous chloride aqueous solution (the aqueous solution contained water, stannous chloride with a concentration of 60 g / L, and 15 ml / L of concentrated hydrochloric acid) at a ratio of 30 g / L, and stirred at 50° C. for 20 min; then placed in a palladium chloride aqueous solution (the aqueous solution contained water, 0.6 g / L of palladium chloride, and 15 ml / L of concentrated hydrochloric acid), and stirred at 50° C. for 20 min; the treated microspheres were filtered and dried to obtain intermediate hollow microspheres A;

[0088] 2) adding 15.5 g / L of the intermediate hollow microspheres A obtained in step 1) to a treatment solution containing 35 g / L cobalt sulfate, 40 g / L sodium hypophosphite, 35 g / L ammonium sulfate, 60 g / L potassium sodium tartrate, and aqueous ammonia (the amount of aqueous ammonia added is such that the pH of the treatment solution is approximately 10.5), stirring in a water bath at 70° C. for 25 min, filtering, and drying to obtain intermediate hollow microspheres B;

[0089] 3) The intermediate hollow microspheres B obtained in step 2) were treated in a flowing air atmosphere at 500° C. for 12 min to obtain hollow microspheres 2.

[0090] The structure of the hollow microsphere 2 is: a hollow core, a glass shell layer from the inside out, a magnetic metal shell layer covering the glass shell layer, and a magnetic metal oxide shell layer covering the magnetic metal shell layer.

[0091] The mass fractions of glass, magnetic metal (cobalt), and magnetic metal oxide (cobaltous oxide) in the hollow microspheres 2 are 68.8%, 13.8%, and 17.4%, respectively.

[0092] Preparation of composite foam:

[0093] 4) Hollow microsphere 1 (glass hollow microsphere, density 0.5g / cm 3 , with an internal cavity diameter of 42 microns) and hollow microspheres 2 in a volume ratio of 5:1, and then mixed with TDE-85 epoxy resin (the volume ratio of the sum of hollow microspheres 1 and hollow microspheres 2 to resin is 21:29). After mixing, the mixture is loaded into a mold (casting method), homogenized by vibration on a vibration table, and vacuum degassing is performed in a vacuum box. The mixture is then cured and molded at 80°C for 5 hours, 120°C for 5 hours, and 160°C for 5 hours. After molding, the composite foam is demolded and the uneven surface area is removed by lathing to obtain the composite foam. In the composite foam, the total volume percentage of the hollow microspheres is 45%.

[0094] The density of the high-strength, high-durability composite foam is 0.89 g / cm 3 The uniaxial compressive strength is 127.9 MPa. After wet heat treatment, the uniaxial compressive strength decreases by 6.9%. The thermal conductivity is 0.198 W / m·K.

[0095] Example 5

[0096] A high-strength, high-durability composite foam based on preformed hollow microspheres is prepared by a method comprising the following steps:

[0097] Preparation of hollow microspheres 2 (magnetic metal hollow microspheres):

[0098] 1) Glass hollow microspheres (density 0.46 g / cm 3, with an internal cavity diameter of 18 microns) was placed in a stannous chloride aqueous solution (the aqueous solution contained water, stannous chloride with a concentration of 60 g / L, and 15 ml / L of concentrated hydrochloric acid) at a ratio of 40 g / L, and stirred at 50° C. for 22 minutes; then placed in a palladium chloride aqueous solution (the aqueous solution contained water, 0.6 g / L of palladium chloride, and 15 ml / L of concentrated hydrochloric acid), and stirred at 50° C. for 25 minutes; the treated microspheres were filtered and dried to obtain intermediate hollow microspheres A;

[0099] 2) adding 22.3 g / L of the intermediate hollow microspheres A obtained in step 1) to a treatment solution containing 25 g / L cobalt sulfate, 35 g / L sodium hypophosphite, 30 g / L ammonium sulfate, 50 g / L potassium sodium tartrate, and aqueous ammonia (the amount of aqueous ammonia added is such that the pH of the treatment solution is approximately 10.5), stirring in a water bath at 75° C. for 25 min, filtering, and drying to obtain intermediate hollow microspheres B;

[0100] 3) The intermediate hollow microsphere B obtained in step 2) was treated in a flowing air atmosphere at 400° C. for 10 min to obtain hollow microsphere 2.

[0101] The structure of the hollow microsphere 2 is: a hollow core, a glass shell layer from the inside out, a magnetic metal shell layer covering the glass shell layer, and a magnetic metal oxide shell layer covering the magnetic metal shell layer.

[0102] The mass fractions of glass, magnetic metal (cobalt), and magnetic metal oxide (cobaltous oxide) in the hollow microspheres 2 are 80.6%, 4%, and 15.4%, respectively.

[0103] Preparation of composite foam:

[0104] 4) Hollow microsphere 1 (glass hollow microsphere, density 0.52g / cm 3 , with an internal cavity diameter of 41 microns) and hollow microspheres 2 in a volume ratio of 7:1, and then mixed with an epoxy resin mixed with E-51 and TDE-85 in a mass ratio of 1:1 (the volume ratio of the sum of hollow microspheres 1 and hollow microspheres 2 to the resin is 53:47), and after mixing, loaded into a mold (casting method), homogenized by vibration on a vibration table, and vacuum defoamed in a vacuum box. Then, the composite foam was cured and molded by successively keeping the temperature at 80°C for 4 hours, 120°C for 4 hours, and 150°C for 3 hours. After molding, the composite foam was demolded and the uneven surface area was removed by turning to obtain the composite foam. In the composite foam, the total volume percentage of the hollow microspheres is 55%.

[0105] The density of the high-strength, high-durability composite foam is 0.83 g / cm 3 The uniaxial compressive strength is 130.2 MPa. After wet heat treatment, the uniaxial compressive strength decreases by 7.3%. The thermal conductivity is 0.194 W / m·K.

[0106] Example 6

[0107] A high-strength, high-durability composite foam based on preformed hollow microspheres is prepared by a method comprising the following steps:

[0108] Preparation of hollow microspheres 2 (magnetic metal hollow microspheres):

[0109] 1) Glass hollow microspheres (density 0.38g / cm 3 , with an internal cavity diameter of 39 microns) was placed in a stannous chloride aqueous solution (the aqueous solution contained water, stannous chloride with a concentration of 60 g / L, and 15 ml / L of concentrated hydrochloric acid) at a ratio of 30 g / L, and stirred at 50° C. for 18 minutes; then placed in a palladium chloride aqueous solution (the aqueous solution contained water, 0.6 g / L of palladium chloride, and 15 ml / L of concentrated hydrochloric acid), and stirred at 50° C. for 25 minutes; the treated microspheres were filtered and dried to obtain intermediate hollow microspheres A;

[0110] 2) adding 15.2 g / L of the intermediate hollow microspheres A obtained in step 1) to a treatment solution containing 40 g / L nickel sulfate, 45 g / L sodium hypophosphite, 40 g / L ammonium sulfate, 80 g / L potassium sodium tartrate, and aqueous ammonia (the amount of aqueous ammonia added is such that the pH of the treatment solution is approximately 10), stirring in a water bath at 55° C. for 20 min, filtering, and drying to obtain intermediate hollow microspheres B;

[0111] 3) The intermediate hollow microspheres B obtained in step 2) were treated in a flowing air atmosphere at 550° C. for 12 min to obtain hollow microspheres 2.

[0112] The structure of the hollow microsphere 2 is: a hollow core, a glass shell layer from the inside out, a magnetic metal shell layer covering the glass shell layer, and a magnetic metal oxide shell layer covering the magnetic metal shell layer.

[0113] The mass fractions of glass, magnetic metal (nickel), and magnetic metal oxide (nickel oxide) in the hollow microspheres 2 are 63.3%, 12.7%, and 24%, respectively.

[0114] Preparation of composite foam:

[0115] 4) Hollow microsphere 1 (glass hollow microsphere, density 0.57g / cm 3, with an internal cavity diameter of 31 microns) and hollow microspheres 2 in a volume ratio of 9:1, and then mixed with an epoxy resin mixed with E-44 and TDE-85 in a mass ratio of 1:2.5 (the volume ratio of the sum of hollow microspheres 1 and hollow microspheres 2 to the resin is 29:21), and after mixing, it is loaded into a mold (casting method), vibrated and homogenized on a vibration table, and vacuum-defoamed in a vacuum box. Then, it is successively kept warm at 80°C for 4h, 120°C for 4h, and 160°C for 4h for curing and molding. After molding, it is demolded and the uneven surface area is removed by turning to obtain the composite foam, in which the total volume percentage of the hollow microspheres is 60%.

[0116] The density of the high-strength, high-durability composite foam is 0.82 g / cm 3 The uniaxial compressive strength is 134.3 MPa. After wet heat treatment, the uniaxial compressive strength decreases by 8.9%. The thermal conductivity is 0.19 W / m·K.

[0117] Comparative Example 1

[0118] A composite foam, compared with Example 4, the only difference is that only hollow microspheres 1 (glass hollow microspheres, density 0.37g / cm 3 ), the volume percentage of hollow microspheres is 62%. The density of the obtained composite foam is 0.69g / cm 3 The uniaxial compressive strength is 118.2 MPa. After heat treatment, the uniaxial compressive strength decreases by 23.6%. The thermal conductivity is 0.18 W / m·K.

[0119] Comparative Example 2

[0120] A composite foam, compared with Example 4, differs only in that only hollow microspheres 2 are used in the preparation of the composite foam, and the volume percentage of the hollow microspheres is 62%. The density of the obtained composite foam is 0.79 g / cm 3 The uniaxial compressive strength is 121.4 MPa. After wet heat treatment, the uniaxial compressive strength decreases by 3.3%. The thermal conductivity is 0.191 W / m·K.

[0121] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A high-strength, high-durability composite foam, characterized in that: The composite foam is obtained by mixing raw materials including resin, glass hollow microspheres, and magnetic metal hollow microspheres and then molding them; wherein, The magnetic metal hollow microspheres are of a core-shell structure, wherein the core is a cavity and the shell is composed of a glass shell layer, a magnetic metal shell layer covering the glass shell layer, and a magnetic metal oxide shell layer covering the magnetic metal shell layer. Wherein, the material of the magnetic metal spherical shell layer is magnetic metal, and the material of the magnetic metal oxide spherical shell layer is the oxide of the magnetic metal; The volume ratio of the glass hollow microspheres to the magnetic metal hollow microspheres is 9:1-2:

1.

2. The composite foam according to claim 1, characterized in that The density of the composite foam is 0.5-0.9 g / cm 3 , In the composite foam, the density of the glass hollow microspheres is 0.15-0.6 g / cm 3 The density of magnetic metal hollow microspheres is ±0.05 g / cm2 of the density of glass hollow microspheres. 3 within the range.

3. The composite foam according to claim 1, characterized in that In the composite foam, the total content of the glass hollow microspheres and the magnetic metal hollow microspheres is 45-65% by volume.

4. The composite foam according to claim 1, wherein The magnetic metal hollow microspheres comprise, by mass percentage, 60-86% of glass hollow microspheres, 3-18% of magnetic metal shell layers, and 5-25% of magnetic metal oxide shell layers; and / or The magnetic metal is selected from one or more of nickel, cobalt and iron.

5. The composite foam according to claim 1, wherein The resin is selected from one or more of epoxy resin, unsaturated polyester resin, phenolic resin, polyurethane resin and polystyrene.

6. The composite foam according to claim 1, wherein The preparation of the magnetic metal hollow microspheres comprises the following steps: The glass hollow microspheres are sequentially placed in a stannous chloride aqueous solution and a palladium chloride aqueous solution, and stirred at 50-55° C. for 15-25 minutes, filtered, and dried to obtain surface-activated glass hollow microspheres. placing the surface-activated glass hollow microspheres in a chemical reduction treatment solution containing the ion source salt of the magnetic metal, stirring and reacting in a water bath at 55-85° C. for 20-30 minutes to form a magnetic metal shell covering the glass hollow microspheres on the surface of the glass hollow microspheres; The surface of the magnetic metal spherical shell is oxidized in an air atmosphere to obtain the magnetic metal hollow microspheres.

7. The composite foam according to claim 6, characterized in that The composition of the stannous chloride aqueous solution comprises: Water, and relative to water, Stannous chloride at a concentration of 50-60 g / L and concentrated hydrochloric acid at a concentration of 10-15 ml / L; and / or The composition of the palladium chloride aqueous solution comprises: Water, and relative to water, 0.5-0.6 g / L palladium chloride and 10-15 ml / L concentrated hydrochloric acid; and / or The concentration of the glass hollow microspheres in the stannous chloride aqueous solution and the palladium chloride aqueous solution is 20-50 g / L.

8. The composite foam according to claim 6, wherein The chemical reduction treatment solution comprises: Water, and relative to water, The ion source salt of the magnetic metal with a concentration of 20-50 g / L, the stabilizer with a concentration of 30-100 g / L, the reducing agent with a concentration of 80-150 g / L, and A pH regulator for adjusting the pH of the chemical reduction treatment solution to 9.5-11; Preferably, the concentration of the surface-activated glass hollow microspheres in the chemical reduction treatment solution is 15-50 g / L.

9. The composite foam according to claim 6, wherein The oxidation temperature is 350-550° C. and the oxidation time is 5-15 minutes.

10. The method for preparing a composite foam according to any one of claims 1 to 9, wherein: The steps include: The glass hollow microspheres, magnetic metal hollow microspheres and resin are mixed evenly and placed in a mold. After homogenization by vibration and vacuum degassing, the mixture is solidified and molded, and demolded to obtain the composite foam.

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