Lightweight high-strength multifunctional polyurethane foam based on cose nanosheet composite and preparation method thereof

Abstract

This invention belongs to the field of polyurethane materials technology, specifically relating to a lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets and its preparation method. The lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets of this invention comprises component A and component B. Component A includes modified CoSe nanosheets, a flame retardant, a foam stabilizer, a catalyst, and a blowing agent. Component B includes isocyanate. The modified CoSe nanosheets are CoSe nanosheets modified with a silane coupling agent. This invention uses a hydrothermal method to synthesize CoSe nanosheets, followed by silane coupling agent modification. The resulting modified CoSe nanosheets, combined with polyether polyols, constitute component A. Components A and B are then prepared. The preparation method of the lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets provided by this invention has a stable process, and the polyurethane foam material prepared by this invention has good mechanical properties and diverse functions.

Description

Technical Field

[0001] This invention belongs to the field of polyurethane materials technology, specifically relating to lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets and its preparation method. Background Technology

[0002] Polyurethane foam is a polymer material produced by the polymerization reaction of polyols and polyisocyanates, possessing a rich porous structure. Due to its lightweight, porous nature, good sound and heat insulation properties, and excellent flexibility, this material is widely used in packaging, construction, furniture, transportation, and electronic equipment. However, traditional polyurethane foam has inherent limitations in mechanical strength (such as tensile strength and modulus), electrical conductivity, and electromagnetic properties (such as static elimination and electromagnetic shielding). This restricts its further application in high-end fields requiring lightweight, high strength, and intelligent features, such as aerospace, flexible electronics, and precision instrument protection.

[0003] To overcome the aforementioned shortcomings, a major direction for improvement in existing technologies is to add functional nanofillers to the polyurethane matrix to construct composite materials. Common fillers include carbon nanotubes (CNTs), graphene, and other carbon-based materials. Studies have shown that the introduction of these nanofillers can effectively improve the mechanical properties and electrical conductivity of composite materials. For example, incorporating functionalized carbon nanotubes into a thermoplastic polyurethane (TPU) matrix through in-situ polymerization can significantly improve the tensile strength and thermal stability of the material. Furthermore, constructing a multidimensional heterostructure by combining two-dimensional sheet-like carbonyl iron (FCI) with cobalt@nitrogen-doped carbon nanotubes (Co@NCNTs), and then combining it with polyurethane, can yield thin film materials that possess both excellent flexibility and electromagnetic wave absorption properties. However, these carbon-based fillers still face some challenges in practical applications: First, carbon nanotubes, graphene, and other materials have large specific surface areas and high surface energies, making them prone to agglomeration in polymer matrices, which leads to difficulties in dispersion and affects the uniformity and stability of performance; second, the production cost of high-quality carbon materials is relatively high; and finally, single-type carbon fillers may have functional limitations in certain application scenarios (such as when it is necessary to achieve both high electromagnetic loss and good mechanical properties at the same time).

[0004] Besides carbon-based fillers, researchers have also explored the modification of polyurethane by other elements or compounds. For example, some technical solutions have attempted to introduce selenium (Se) into the polyurethane system, but these mainly focus on two approaches: one is to mix elemental selenium as a trace additive with metal oxides, aiming to endow foam products with specific health benefits. This approach does not introduce selenium in the form of nanocompounds with specific morphology and functions. The other approach is to introduce "double selenium bonds" as dynamic covalent bonds into the polyurethane molecular backbone through chemical synthesis to endow the material with self-healing properties. This is a chemical modification at the molecular level, rather than systematically regulating the macroscopic properties of the material through physical blending of nanofillers.

[0005] Patent CN116453865A developed a method for directly growing CoSe nanosheet arrays on nickel foam substrates. The resulting composite material, due to its three-dimensional network structure and abundant active sites, exhibits excellent electrochemical performance as an electrode material for supercapacitors. Another study also prepared cobalt selenide compound nanotube arrays supported on nickel foam via hydrothermal and selenization methods and applied them to the hydrogen evolution reaction in water electrolysis. However, these existing technologies share a common feature: they all use cobalt selenide as the active material to grow or support on rigid, dense conductive substrates such as nickel foam, and their application targets are concentrated in the fields of electrochemical energy storage or catalysis. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a method for preparing lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheet composite. The process is stable and can be mass-produced. The polyurethane foam material prepared by the present invention has good mechanical properties and diverse functions.

[0007] The lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets described in this invention comprises component A and component B. Component A includes modified CoSe nanosheets, flame retardant, foam stabilizer, catalyst, and blowing agent, while component B includes isocyanate.

[0008] The modified CoSe nanosheets are CoSe nanosheets modified with a silane coupling agent. The catalyst is an amine catalyst, and the blowing agent is cyclopentane.

[0009] The method for preparing lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets includes the following steps:

[0010] (1) Hexagonal CoSe nanosheets were synthesized by hydrothermal method; CoSe nanosheet composite material was dispersed in solvent, and silane coupling agent was added to carry out surface modification reaction. After the reaction was completed, the surface was separated and dried to obtain modified CoSe nanosheets with surface grafted organic functional groups.

[0011] (2) After dehydrating and degassing the polyether polyol under vacuum and heating conditions, add the modified CoSe nanosheets obtained in step (1), disperse them evenly under high-speed shearing and ultrasonic assistance to form a slurry, and then add foam stabilizer, flame retardant, catalyst and foaming agent, stir evenly to obtain component A;

[0012] (3) Mix component A with polyisocyanate component B, pour the resulting mixture into a preheated mold, and cure it after closing the mold;

[0013] (4) Demolding and curing to obtain lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets.

[0014] The specific steps for synthesizing CoSe nanosheet composite materials via the hydrothermal method include:

[0015] a. Cobalt salt and organic amine were dissolved in water and transferred to a reactor containing nickel foam for hydrothermal reaction. After the reaction was completed, the mixture was cooled, washed, and dried to obtain Co(OH)2 nanosheets loaded on nickel foam.

[0016] b. Dissolve sodium borohydride in water, then add selenium powder and mix to obtain a transparent selenium-containing solution; mix the transparent selenium-containing solution with the Co(OH)2 nanosheet material obtained in step a and carry out a hydrothermal reaction. After the reaction is completed, cool, wash and dry to obtain a CoSe nanosheet composite material loaded on nickel foam.

[0017] c. Peel the CoSe nanosheet composite material from the nickel foam substrate.

[0018] The hydrothermal temperature in step a is 80-90℃, and the hydrothermal holding time is 9-11 hours; the hydrothermal temperature in step b is 100-150℃, and the hydrothermal holding time is 9-11 hours. The cobalt salt is cobalt nitrate hexahydrate (Co(NO3)2·6H2O), and the organic amine is hexamethylenetetramine (C6H2O). 12 N4).

[0019] Step (1) The mass of the silane coupling agent added is 3%~8% of the CoSe nanosheet composite material. After adding the silane coupling agent, the mixture is refluxed at 70~80℃ for 4~6h.

[0020] The high-speed shearing speed in step (2) is 2000~3000 rpm.

[0021] In step (3), the mass ratio of component A to polyisocyanate component B is 1:1.2. After mixing component A and polyisocyanate component B, mix at 2500~4000 rpm for 5-10 seconds. After closing the mold, cure at 60~70℃ for 20~30 minutes.

[0022] The aging temperature in step (4) is 75~85℃ and the aging time is 4~6h.

[0023] This invention uses cobalt nitrate hexahydrate (Co(NO3)2•6H2O) and hexamethylenetetramine (C6H) 12 Using N4, sodium borohydride (NaBH4), and selenium powder (Se) as raw materials, cobalt selenide nanosheets were synthesized by hydrothermal method, and their surface was modified with silane coupling agent to improve dispersibility. Subsequently, the modified nanofiller was uniformly dispersed in polyether polyol, and then mixed with isocyanate, foaming agent, catalyst and other components and foamed and cured.

[0024] Specifically, the preparation method of the lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets includes the following steps:

[0025] (1) First, mix Co(NO3)2•6H2O and C6H 12 N4 was added to 30 mL of deionized water and magnetically stirred for 30 min. The solution was then transferred to a reaction vessel lined with polytetrafluoroethylene and filled with nickel foam. The reaction vessel was heated to 80-90 °C and maintained for 9-11 h. The solution was then allowed to cool naturally to room temperature. The nickel foam loaded with Co(OH)2 was ultrasonically washed several times with deionized water. Subsequently, the obtained product was treated in a vacuum drying oven at 60 °C for 24 h to obtain the Co(OH)2 nanosheet composite material.

[0026] (2) Weigh NaBH4 and 30 mL of deionized water, and pour them into a beaker. Stir magnetically to completely dissolve NaBH4. Weigh Se powder and stir it together with the above mixed solution magnetically to dissolve the Se powder and obtain a transparent solution. Then, transfer the transparent solution to a high-pressure reactor with a polytetrafluoroethylene liner that has Co(OH)2 nanosheets fixed inside. Heat the reactor to the preset temperature and maintain it for 10 h. After the hydrothermal reaction is completed, allow the obtained material to cool naturally to room temperature, wash it several times with deionized water using ultrasound, and finally dry it in a vacuum drying oven at 60 °C to peel the CoSe nanosheet composite material off the nickel foam substrate to obtain the CoSe nanosheet composite material.

[0027] (3) The obtained CoSe nanosheet composite material was dispersed in anhydrous ethanol, and 3%~8% of silane coupling agent of CoSe nanosheet composite material was added. The mixture was refluxed at 70~80℃ for 4~6h. After the reaction was completed, the mixture was centrifuged, washed and dried to obtain modified CoSe nanosheets with surface grafted organic functional groups.

[0028] (4) In a stirred tank, add polyether polyol, and after dehydration and degassing under vacuum and heating at 40~50℃, add the modified CoSe nanosheets and flame retardant obtained above. Disperse under high-speed shear at 2000~3000rpm and ultrasonic assistance for 30~60min to form a uniform and stable slurry. Then add foam stabilizer, catalyst and foaming agent, and continue to stir evenly to obtain component A.

[0029] (5) Adjust the temperature of component A to 23~27℃, take component A and mix it with polyisocyanate component B at the same temperature at a ratio of 1:1.2, and mix in a high-speed mixer at 2500~4000rpm for 5~10s. At the beginning of the milky white stage, quickly pour the mixture into a mold preheated to 45~55℃.

[0030] (6) After the mold is closed, place it in an oven at 60~70℃ for 20~30 min to cure. After demolding, mature the foam product at 75~85℃ for 4~6 h to ensure complete reaction and stable performance.

[0031] Compared with the prior art, the beneficial effects of the present invention are:

[0032] (1) The preparation method of lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets of the present invention is simple to operate, easy to control, and the raw materials are readily available and low in cost; it solves the problems of low strength, non-conductivity, and lack of electromagnetic shielding ability of traditional foams, and realizes the lightweight, high strength, conductivity, and shielding multifunctionality of a single material.

[0033] (2) The lightweight, high-strength, multifunctional polyurethane foam prepared using this invention employs nanosheets as reinforcing points to refine the pores, hindering molecular chain slippage and increasing the foam's compressive strength. CoSe nanosheets form a three-dimensional conductive network within the foam skeleton, providing conductive pathways and achieving efficient electromagnetic shielding. The nanofillers physically block heat transfer, catalyze the matrix to carbonize, and increase the thermal decomposition temperature. This composite material is particularly suitable for applications with stringent requirements for weight, strength, and electromagnetic environment, such as sound and heat insulation and electromagnetic protection padding in aircraft cabins, packaging for precision electronic instruments, and flexible pressure sensor substrates. Detailed Implementation

[0034] The present invention will be further described below with reference to specific embodiments.

[0035] The commercially available sources of the raw materials and additives used in this invention are as follows:

[0036] Polyether polyol R5118G, color value: 7, viscosity: 8217 mPa·s (25℃), hydroxyl value: 384mgKOH / g, moisture: 0.04wt%, pH: 10;

[0037] Modified MDI: PM200, viscosity: 200 mPa·s (25℃), functionality: 2.6, density: 1.23 g / cm³; color: dark brown.

[0038] Cobalt nitrate hexahydrate (Co(NO3)2•6H2O): Sinopharm Chemical Reagent Co., Ltd.

[0039] Cyclohexamethylenetetramine (C6H) 12 N4): Sinopharm Chemical Reagent Co., Ltd.

[0040] Sodium borohydride (NaBH4): Sinopharm Chemical Reagent Co., Ltd.

[0041] Selenium powder (Se): Aladdin Biochemical Technology Co., Ltd.

[0042] Nickel Foam: Changsha Liyuan New Materials Co., Ltd.

[0043] Silane coupling agent KH-550: Nanjing Chenggong Organosilicon Materials Co., Ltd.

[0044] Anhydrous ethanol: Sinopharm Chemical Reagent Co., Ltd.

[0045] Polyether polyol R5118G: Shandong Yinuowei New Materials Co., Ltd.

[0046] Flame retardant (pentamethyldiethylenetriamine TCPP): Wuhan Adama.

[0047] Catalyst (pentamethyldiethylenetriamine PC-5): Shanghai Qihe Chemical Co., Ltd.

[0048] Catalyst (N,N-dimethylcyclohexylamine) PC-8: Shanghai Qihe Chemical Co., Ltd.

[0049] Catalyst (N,N-dimethylbenzylamine BDMA): Dehua Wanda Chemical Co., Ltd.

[0050] Catalyst (2-hydroxy-N,N,N-trimethyl-1-propylaminocarbamate TMR-2): Shanghai Qiguang Industry & Trade Co., Ltd.

[0051] Polyurethane foam stabilizer S1: Momentive Advanced Materials Co., Ltd.

[0052] Cyclopentane (CP): Shanghai Pailco Chemical Materials Co., Ltd.

[0053] Example 1

[0054] The method for preparing lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets includes the following steps:

[0055] (1) First, mix 2.9104g of Co(NO3)2·6H2O and 2.8035g of C6H 12 N4 was added to 30 mL of deionized water and magnetically stirred for 30 min. The solution was then transferred to the inner liner of a reaction vessel lined with polytetrafluoroethylene and filled with nickel foam. The reaction vessel was heated to 85 °C and maintained for 10 h. The solution was then naturally cooled to room temperature. The nickel foam loaded with Co(OH)2 was ultrasonically washed 5 times with deionized water. Subsequently, the obtained product was treated in a vacuum drying oven at 60 °C for 24 h to obtain Co(OH)2 nanosheet material.

[0056] (2) Weigh 0.908g of NaBH4 and 30mL of deionized water, and pour them into a beaker in sequence. Stir with a magnetic force to completely dissolve NaBH4. Weigh 0.2368g of Se powder and stir it together with the above mixed solution with a magnetic force to dissolve the Se powder and obtain a transparent solution. Then, transfer the transparent solution to a high-pressure reactor with a polytetrafluoroethylene liner that fixes the Co(OH)2 composite material. Heat the reactor to 140℃ and keep it for 10h. After the hydrothermal reaction is completed, let the obtained material cool naturally to room temperature, wash it with deionized water three times by ultrasonication, and finally dry it in a vacuum drying oven at 60℃ to peel the CoSe nanosheet composite material off the substrate nickel foam to obtain the CoSe nanosheet composite material.

[0057] (3) The obtained CoSe nanosheet composite material was dispersed in anhydrous ethanol, and 4% of the mass of the CoSe nanosheet composite material was added with silane coupling agent KH550. The mixture was refluxed at 75°C for 5 h. After the reaction was completed, the mixture was centrifuged, washed and dried to obtain modified CoSe nanosheets with surface grafted organic functional groups.

[0058] (4) In a stirred tank, add 100g of R5118G, dehydrate and degas under vacuum heating at 45°C, add 1g of the modified CoSe nanosheets obtained above and 10g of TCPP, disperse for 40min under high-speed shearing at 2500rpm and ultrasonic assistance to form a uniform and stable slurry, then add 1g of S1, 0.2g of PC-5, 0.3g of PC-8, 0.1g of BDMA, 0.4g of TMR-2, 3g of water and 15g of CP, and continue to stir evenly to obtain component A.

[0059] (5) Adjust the temperature of component A to 25°C, and quickly mix 60g of component A and 72g of PM200 at the same temperature. Mix at 3000rpm for 6s in a high-speed mixer. At the beginning of the milky white period, quickly pour the mixture into a mold preheated to 50°C.

[0060] (6) After the mold is closed, place it in a 65℃ oven to cure for 25 minutes. After demolding, let the foam product mature at 80℃ for 5 hours.

[0061] Example 2

[0062] The method for preparing lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets includes the following steps:

[0063] (1) First, mix 2.9104g of Co(NO3)2·6H2O and 2.8035g of C6H 12N4 was added to 30 mL of deionized water and magnetically stirred for 30 min. The solution was then transferred to the inner liner of a reaction vessel lined with polytetrafluoroethylene and filled with nickel foam. The reaction vessel was heated to 85 °C and maintained for 10 h. The solution was then naturally cooled to room temperature. The nickel foam loaded with Co(OH)2 was ultrasonically washed three times with deionized water. Subsequently, the obtained product was treated in a vacuum drying oven at 60 °C for 24 h to obtain the Co(OH)2 composite material.

[0064] (2) Weigh 0.908g of NaBH4 and 30mL of deionized water, and pour them into a beaker in sequence. Stir with a magnetic force to completely dissolve NaBH4. Weigh 0.2368g of Se powder and stir it together with the above mixed solution with a magnetic force to dissolve the Se powder and obtain a transparent solution. Then, transfer the transparent solution to a high-pressure reactor with a polytetrafluoroethylene liner that fixes the Co(OH)2 composite material. Heat the reactor to 130℃ and keep it for 10h. After the hydrothermal reaction is completed, let the obtained material cool naturally to room temperature, wash it with deionized water three times by ultrasonication, and finally dry it in a vacuum drying oven at 60℃ to peel the CoSe nanosheet composite material off the substrate nickel foam to obtain the CoSe nanosheet composite material.

[0065] (3) The obtained CoSe nanosheet composite material was dispersed in anhydrous ethanol, and 3% of KH550 by mass of the CoSe nanosheet composite material was added. The mixture was refluxed at 70°C for 6 hours. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain modified CoSe nanosheets with surface grafted organic functional groups.

[0066] (4) In a stirred tank, add 100g of R5118G, dehydrate and degas under vacuum heating at 45°C, add 1g of the modified CoSe nanosheets obtained above and 10g of TCPP, disperse for 60min under high-speed shearing at 3000rpm and ultrasonic assistance to form a uniform and stable slurry, then add 1g of S1, 0.2g of PC-5, 0.3g of PC-8, 0.1g of BDMA, 0.4g of TMR-2, 3g of water and 15g of CP, and continue to stir evenly to obtain component A.

[0067] (5) Adjust the temperature of component A to 27°C, mix 60g of component A and 72g of PM200 at the same temperature quickly, mix at 2500rpm for 10s in a high-speed mixer, and pour the mixture into a mold preheated to 45°C when the milky white stage begins.

[0068] (6) After the mold is closed, place it in a 60℃ oven to cure for 20 minutes. After demolding, let the foam product mature at 80℃ for 6 hours.

[0069] Example 3

[0070] The method for preparing lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets includes the following steps:

[0071] (1) First, mix 2.9104g of Co(NO3)2·6H2O and 2.8035g of C6H 12 N4 was added to 30 mL of deionized water and magnetically stirred for 30 min. The solution was then transferred to the inner liner of a reaction vessel lined with polytetrafluoroethylene and filled with nickel foam. The reaction vessel was heated to 85 °C and maintained for 10 h. The solution was then naturally cooled to room temperature. The nickel foam loaded with Co(OH)2 was ultrasonically washed four times with deionized water. Subsequently, the obtained product was treated in a vacuum drying oven at 60 °C for 24 h to obtain Co(OH)2 nanosheet material.

[0072] (2) Weigh 0.908g of NaBH4 and 30mL of deionized water, and pour them into a beaker in sequence. Stir with a magnetic force to completely dissolve NaBH4. Weigh 0.2368g of Se powder and stir it together with the above mixed solution with a magnetic force to dissolve the Se powder and obtain a transparent solution. Then, transfer the transparent solution to a high-pressure reactor with a polytetrafluoroethylene liner that is fixed with Co(OH)2 material. Heat the reactor to 120℃ and keep it for 10h. After the hydrothermal reaction is completed, let the obtained material cool naturally to room temperature, wash it with deionized water three times by ultrasonication, and finally dry it in a vacuum drying oven at 60℃ to peel the CoSe nanosheet composite material off the substrate nickel foam to obtain the CoSe nanosheet composite material.

[0073] (3) The obtained CoSe nanosheet composite material was dispersed in anhydrous ethanol, and 8% of KH550 by mass of the CoSe nanosheet composite material was added. The mixture was refluxed at 70°C for 6 hours. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain modified CoSe nanosheets with surface grafted organic functional groups.

[0074] (4) In a stirred tank, add 100g of R5118G, dehydrate and degas under vacuum heating at 40℃, add 1g of the modified CoSe nanosheets obtained above and 10g of TCPP, disperse for 60min under high-speed shearing at 2000rpm and ultrasonic assistance to form a uniform and stable slurry, then add 1g of S1, 0.2g of PC-5, 0.3g of PC-8, 0.1g of BDMA, 0.4g of TMR-2, 3g of water and 15g of CP, and continue to stir evenly to obtain component A.

[0075] (5) Adjust the temperature of component A to 25°C, and quickly mix 60g of component A and 72g of PM200 at the same temperature. Mix at 4000rpm for 5s in a high-speed mixer. At the beginning of the milky white period, quickly pour the mixture into a mold preheated to 45°C.

[0076] (6) After the mold is closed, place it in a 70℃ oven to cure for 20 minutes. After demolding, let the foam product mature at 80℃ for 4 hours.

[0077] Example 4

[0078] The method for preparing lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets includes the following steps:

[0079] (1) First, mix 2.9104g of Co(NO3)2·6H2O and 2.8035g of C6H 12 N4 was added to 30 mL of deionized water and magnetically stirred for 30 min. The solution was then transferred to the inner liner of a reaction vessel lined with polytetrafluoroethylene and filled with nickel foam. The reaction vessel was heated to 85 °C and maintained for 10 h. The solution was then naturally cooled to room temperature. The nickel foam loaded with Co(OH)2 was ultrasonically washed four times with deionized water. Subsequently, the obtained product was treated in a vacuum drying oven at 60 °C for 24 h to obtain Co(OH)2 nanosheet material.

[0080] (2) Weigh 0.908g of NaBH4 and 30mL of deionized water, and pour them into a beaker in sequence. Stir with a magnetic force to completely dissolve NaBH4. Weigh 0.2368g of Se powder and stir it together with the above mixed solution with a magnetic force to dissolve the Se powder and obtain a transparent solution. Then, transfer the transparent solution to a high-pressure reactor with a polytetrafluoroethylene liner that is fixed with Co(OH)2 material. Heat the reactor to 110℃ and keep it for 10h. After the hydrothermal reaction is completed, let the obtained material cool naturally to room temperature, wash it with deionized water three times by ultrasonication, and finally dry it in a vacuum drying oven at 60℃ to peel the CoSe nanosheet composite material off the substrate nickel foam to obtain the CoSe nanosheet composite material.

[0081] (3) The obtained CoSe nanosheet composite material was dispersed in anhydrous ethanol, and 4% of KH550 by mass of the CoSe nanosheet composite material was added. The mixture was refluxed at 70°C for 6 hours. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain modified CoSe nanosheets with surface grafted organic functional groups.

[0082] (4) In a stirred tank, add 100g of R5118G, dehydrate and degas under vacuum heating at 45°C, add 1g of the modified CoSe nanosheets obtained above and 10g of TCPP, disperse for 35min under high-speed shearing at 2500rpm and ultrasonic assistance to form a uniform and stable slurry, then add 1g of S1, 0.2g of PC-5, 0.3g of PC-8, 0.1g of BDMA, 0.4g of TMR-2, 3g of water and 15g of CP, and continue to stir evenly to obtain component A.

[0083] (5) Adjust the temperature of component A to 25°C, mix 60g of component A and 72g of PM200 at the same temperature quickly, mix at 4000rpm for 5s in a high-speed mixer, and pour the mixture into a mold preheated to 50°C when the milky white stage begins.

[0084] (6) After the mold is closed, place it in a 65℃ oven to cure for 25 minutes. After demolding, let the foam product mature at 80℃ for 5 hours.

[0085] Example 5

[0086] The method for preparing lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets includes the following steps:

[0087] (1) First, mix 2.9104g of Co(NO3)2·6H2O and 2.8035g of C6H 12 N4 was added to 30 mL of deionized water and magnetically stirred for 30 min. The solution was then transferred to the inner liner of a reaction vessel lined with 50 mL of polytetrafluoroethylene containing nickel foam. The reaction vessel was heated to 85 °C and maintained for 10 h. The solution was then naturally cooled to room temperature. The nickel foam loaded with Co(OH)2 was ultrasonically washed four times with deionized water. The resulting material was then treated in a vacuum drying oven at 60 °C for 24 h to obtain Co(OH)2 nanosheet material.

[0088] (2) Weigh 0.908g of NaBH4 and 30mL of deionized water, and pour them into a beaker in sequence. Stir with a magnetic force to completely dissolve NaBH4. Weigh 0.2368g of Se powder and stir it together with the above mixed solution with a magnetic force to dissolve the Se powder and obtain a transparent solution. Then, transfer the transparent solution to a 50mL high-pressure reactor with a polytetrafluoroethylene liner that is fixed with Co(OH)2 material. Heat the reactor to 150℃ and keep it for 10h. After the hydrothermal reaction is completed, let the obtained material cool naturally to room temperature, wash it with deionized water three times by ultrasonication, and finally dry it in a vacuum drying oven at 60℃ to peel the CoSe nanosheet composite material off the substrate nickel foam to obtain the CoSe nanosheet composite material.

[0089] (3) The obtained CoSe nanosheet composite material was dispersed in anhydrous ethanol, and 5% KH550 of the mass of the CoSe nanosheet composite material was added. The mixture was refluxed at 70°C for 6 hours. After the reaction was completed, the mixture was centrifuged, washed and dried to obtain modified CoSe nanosheets with surface grafted organic functional groups.

[0090] (4) In a stirred tank, add 100g of R5118G, dehydrate and degas under vacuum heating at 45°C, add 1g of the modified CoSe nanosheets obtained above and 10g of TCPP, disperse for 40min under high-speed shearing at 2500rpm and ultrasonic assistance to form a uniform and stable slurry, then add 1g of S1, 0.2g of PC-5, 0.3g of PC-8, 0.1g of BDMA, 0.4g of TMR-2, 3g of water and 15g of CP, and continue to stir evenly to obtain component A.

[0091] (5) Adjust the temperature of component A to 25°C, mix 60g of component A and 72g of PM200 at the same temperature quickly, mix at 4000rpm for 7s in a high-speed mixer, and pour the mixture into a mold preheated to 50°C when the milky white stage begins.

[0092] (6) After the mold is closed, place it in a 65℃ oven to cure for 25 minutes. After demolding, let the foam product mature at 80℃ for 4 hours.

[0093] Comparative Example 1

[0094] The method for preparing lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets includes the following steps:

[0095] (1) In a stirred tank, add 100g of R5118G, dehydrate and degas under vacuum heating at 45℃, add 10g of TCPP, disperse for 40min under high-speed shearing at 2500rpm and ultrasonic assistance to form a uniform and stable slurry, then add 1g of S1 foam stabilizer, 0.2g of PC-5, 0.3g of PC-8, 0.1g of BDMA, 0.4g of TMR-2, 3g of water and 15g of CP, and continue to stir evenly to obtain component A.

[0096] (2) Adjust the temperature of component A to 25°C, and mix 60g of component A and 72g of PM200 at the same temperature quickly. Mix at 3000rpm for 6s in a high-speed mixer. At the beginning of the milky white period, quickly pour the mixture into a mold preheated to 50°C.

[0097] (3) After the mold is closed, place it in a 65℃ oven to cure for 25 minutes. After demolding, let the foam product mature at 80℃ for 5 hours.

[0098] Comparative Example 2

[0099] The method for preparing lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets includes the following steps:

[0100] (1) First, mix 2.9104g of Co(NO3)2·6H2O and 2.8035g of C6H 12 N4 was added to 30 mL of deionized water and magnetically stirred for 30 min. The solution was then transferred to the inner liner of a reaction vessel lined with polytetrafluoroethylene and filled with nickel foam. The reaction vessel was heated to 85 °C and maintained for 10 h. The solution was then naturally cooled to room temperature. The nickel foam loaded with Co(OH)2 was ultrasonically washed 5 times with deionized water. Subsequently, the obtained product was treated in a vacuum drying oven at 60 °C for 24 h to obtain Co(OH)2 nanosheet material.

[0101] (2) In a stirred tank, add 100g of R5118G, dehydrate and degas under vacuum heating at 45℃, add more than 1g of prepared Co(OH)2 nanosheets and 10g of TCPP, disperse for 40min under high-speed shearing at 2500rpm and ultrasonic assistance to form a uniform and stable slurry, then add 1g of S1, 0.2g of PC-5, 0.3g of PC-8, 0.1g of BDMA, 0.4g of TMR-2, 3g of water and 15g of CP, and continue to stir evenly to obtain component A.

[0102] (3) Adjust the temperature of component A to 25°C, mix 60g of component A and 72g of PM200 at the same temperature quickly, mix at 3000rpm for 6s in a high-speed mixer, and pour the mixture into a mold preheated to 50°C when the milky white period begins.

[0103] (4) After the mold is closed, place it in a 65℃ oven to cure for 25 minutes. After demolding, let the foam product mature at 80℃ for 5 hours.

[0104] Comparative Example 3

[0105] The method for preparing lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets includes the following steps:

[0106] (1) First, mix 2.9104g of Co(NO3)2·6H2O and 2.8035g of C6H 12 N4 was added to 30 mL of deionized water and magnetically stirred for 30 min. The solution was then transferred to the inner liner of a reaction vessel lined with polytetrafluoroethylene and filled with nickel foam. The reaction vessel was heated to 85 °C and maintained for 10 h. The solution was then naturally cooled to room temperature. The nickel foam loaded with Co(OH)2 was ultrasonically washed 5 times with deionized water. Subsequently, the obtained product was treated in a vacuum drying oven at 60 °C for 24 h to obtain Co(OH)2 nanosheet material.

[0107] (2) Weigh 0.908g of NaBH4 and 30mL of deionized water, and pour them into a beaker in sequence. Stir with a magnetic force to completely dissolve NaBH4. Weigh 0.2368g of Se powder and stir it together with the above mixed solution with a magnetic force to dissolve the Se powder and obtain a transparent solution. Then, transfer the transparent solution to a high-pressure reactor with a polytetrafluoroethylene liner that fixes the Co(OH)2 composite material. Heat the reactor to 140℃ and keep it for 10h. After the hydrothermal reaction is completed, let the obtained material cool naturally to room temperature, wash it with deionized water three times by ultrasonication, and finally dry it in a vacuum drying oven at 60℃ to peel the CoSe nanosheet composite material off the substrate nickel foam to obtain the CoSe nanosheet composite material.

[0108] (3) In a stirred tank, add 100g of R5118G, dehydrate and degas under vacuum heating at 45°C, add 1g of the CoSe nanosheet composite material obtained above and 10g of TCPP, disperse for 40min under high-speed shearing at 2500rpm and ultrasonic assistance to form a uniform and stable slurry, then add 1g of S1, 0.2g of PC-5, 0.3g of PC-8, 0.1g of BDMA, 0.4g of TMR-2, 3g of water and 15g of CP, and continue to stir evenly to obtain component A.

[0109] (4) Adjust the temperature of component A to 25°C, and mix 60g of component A and 72g of PM200 at the same temperature quickly. Mix at 3000rpm for 6s in a high-speed mixer. At the beginning of the milky white period, quickly pour the mixture into a mold preheated to 50°C.

[0110] (5) After the mold is closed, place it in a 65℃ oven to cure for 25 minutes. After demolding, let the foam product mature at 80℃ for 5 hours.

[0111] The polyurethane foam products prepared above were subjected to performance testing, and the test results are shown in Table 1.

[0112] Table 1 Test Results

[0113]

[0114] As can be seen from Table 1 above, Example 1 of the present invention exhibits the best overall performance, being lightweight yet high-strength, with good thermal insulation, high thermal stability, and strong shielding effectiveness. The high density, low strength, and poor thermal insulation of Comparative Examples 1-3 demonstrate that the introduction and structural optimization of CoSe nanosheets are crucial for improving the overall performance of the materials.

Claims

1. A lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets, comprising component A and component B, wherein component A comprises a polyether polyol, characterized in that: Component A further includes modified CoSe nanosheets, flame retardants, foam stabilizers, catalysts, and blowing agents; Component B includes polyisocyanates. The modified CoSe nanosheets are CoSe nanosheets modified with a silane coupling agent.

2. A method for preparing a lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets as described in claim 1, characterized in that: Includes the following steps: (1) CoSe nanosheets were synthesized by a hydrothermal method. The specific steps included: a. Cobalt salt and organic amine were dissolved in water and transferred to a reactor containing nickel foam for hydrothermal reaction. After the reaction was completed, the mixture was cooled, washed, and dried to obtain Co(OH)2 nanosheets loaded on nickel foam. b. Dissolve sodium borohydride in water, then add selenium powder and mix to obtain a transparent selenium-containing solution; mix the transparent selenium-containing solution with the Co(OH)2 nanosheet material obtained in step a and carry out a hydrothermal reaction. After the reaction is completed, cool, wash and dry to obtain a CoSe nanosheet composite material loaded on nickel foam. c. Peel the CoSe nanosheet composite material from the nickel foam substrate; disperse the CoSe nanosheet composite material in a solvent, add a silane coupling agent to carry out a surface modification reaction, and after the reaction is completed, separate and dry to obtain modified CoSe nanosheets with surface grafted organic functional groups. (2) After dehydrating and degassing the polyether polyol under vacuum and heating conditions, add the modified CoSe nanosheets obtained in step (1), disperse them evenly under high-speed shearing and ultrasonic assistance to form a slurry, then add foam stabilizer, flame retardant, catalyst and foaming agent, stir evenly to obtain component A; (3) Mix component A with polyisocyanate component B, pour the resulting mixture into a preheated mold, and cure after closing the mold; (4) Demold and mature to obtain a lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheet composite.

3. The method for preparing lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets according to claim 2, characterized in that: The hydrothermal temperature in step a is 80~90℃, and the hydrothermal holding time is 9~11h; the hydrothermal temperature in step b is 100~150℃, and the hydrothermal holding time is 9~11h.

4. The method for preparing lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets according to claim 2, characterized in that: Step (1) The mass of the silane coupling agent added is 3%~8% of the CoSe nanosheet composite material. After adding the silane coupling agent, the mixture is refluxed at 70~80℃ for 4~6h.

5. The method for preparing lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets according to claim 2, characterized in that: The high-speed shearing speed in step (2) is 2000~3000 rpm.

6. The method for preparing lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets according to claim 2, characterized in that: The mass ratio of component A to polyisocyanate component B in step (3) is 1:1.

2.

7. The method for preparing lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets according to claim 6, characterized in that: After mixing component A with polyisocyanate component B, mix at 2500~4000 rpm for 5-10 seconds.

8. The method for preparing lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets according to claim 7, characterized in that: After closing the mold, cure at 60~70℃ for 20~30 minutes.

9. The method for preparing lightweight, high-strength, multifunctional polyurethane foam based on CoSe nanosheets according to claim 2, characterized in that: The aging temperature in step (4) is 75~85℃ and the aging time is 4~6h.

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