A nanofiber-particle composite reinforced high modulus polyurethane composite material and a method of making the same

Abstract

The application discloses a kind of nanofiber-particle composite reinforced high modulus polyurethane composite material and preparation method thereof.This nanofiber-particle composite reinforced high modulus polyurethane composite material is prepared by resin, curing agent and nanometer reinforcing material composition of polyurethane combination and modified reinforcing fiber according to the step of ultrasonic mixing in mixed processing first.The application forms the topological structure of multi-scale between polyurethane resin and reinforcing fiber by introducing the nanocomposite network reinforcing structure formed by modified nanofiber and particle, and the interaction force between modified nanofiber and nanoparticle is combined in the vicinity of nanofiber, and nanofiber is intertwined and nanoparticle is formed by higher capillary force and intermolecular force to form nanocomposite network structure with extremely high cohesion, and further form the multiphase system with super stability in composite material.Compared with traditional single nanomaterial, nanocomposite network structure has obvious enhancement in stability and interface adhesion capacity.As the hinge of connecting macroscopic reinforcing fiber and resin matrix, the introduction of this composite structure can greatly improve the mechanical properties of material.And the high modulus polyurethane composite material preparation technology has clear mechanism, simple production process, excellent performance, is suitable for large-scale production, and has important significance for the preparation of high-performance composite material components.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of high polymer composite materials, and particularly relates to a nanofiber-particle composite reinforced high modulus polyurethane composite material and a preparation method thereof. BACKGROUND

[0002] Polyurethane is a polymer material prepared by the polymerization reaction of polyols and polyisocyanates. Different structures and properties can be obtained by using different raw materials, and various products such as coatings, adhesives, plastics, fibers, rubbers, etc. from liquid to solid, from soft to hard can be prepared. The polyurethane hardening body has excellent toughness, impact resistance, wear resistance and tear resistance. Polyurethane has simple processing and molding process, and good molding effect can be obtained by injection, casting and other processes, so its application is very wide and the application range is growing rapidly.

[0003] Polyurethane composite material is a fiber reinforced resin composite material prepared by using polyurethane resin as the matrix and glass fiber, carbon fiber, basalt fiber, etc. as the reinforcing material through winding, pultrusion, injection molding and other processes. Compared with traditional resins, polyurethane has better combination with reinforcing materials, so it has excellent impact resistance, mechanical properties and weather resistance. Polyurethane resin does not contain volatile substances such as styrene, which fully meets the relevant requirements of the state for "strengthening the application research and development of green products, and popularizing lightweight and low-power technology and process". Polyurethane has the process advantages of low viscosity and faster molding speed for pultrusion. Polyurethane composite material has the characteristics of low density, good tensile property, impact resistance, durability and strong material designability, and is widely used in the production and manufacturing of window frames, telegraph poles, bathtubs, large automobile parts and other products.

[0004] Under normal circumstances, the rigidity of polyurethane material is low, and it is difficult to fully meet the use scenarios that require high modulus and strength. For example, when used in power grid poles or railway contact net support, the deflection value of the current polyurethane composite material pole body under the same load is much larger than that of the cement pole body and the steel structure pole body of similar size, about 4 times that of the cement pole body. This also makes the traditional polyurethane composite material pole body appear obvious bending phenomenon when subjected to large transverse force, which is difficult to meet the use requirements in related fields.

[0005] Based on the above reasons, the development of polyurethane composite materials with high strength and high modulus while maintaining good toughness has become the research direction of relevant researchers, and is also one of the main development directions of polyurethane composite materials in the future. Patent CN201110330929 discloses a method for preparing high-rigidity polyurethane, which improves its heat resistance and rigidity by introducing trifunctional polymer polyols to produce chemical cross-linking between polyurethane molecules. Patent CN109294215B discloses a high-strength and high-modulus polyurethane composite material, which improves the strength and modulus of the material by introducing polyphenylene ether microsphere particles. The material has high mechanical properties and a simple preparation process. Patent CN115012220A discloses a method for preparing high-strength polyurethane composite materials, which uses surface-sizing grafted polyimide fibers as reinforcing materials to prepare high-strength polyurethane composite materials with excellent flame retardant properties, temperature resistance and UV resistance.

[0006] Since polyurethane composites are relatively complex multiphase systems, existing technologies have not fully studied and utilized the microphase distribution within the system. Therefore, by modifying the phase distribution and phase interface of the system with micro-nanomaterials of appropriate scale, the overall performance of polyurethane composites can be effectively improved, and materials with better mechanical properties and durability can be obtained, which is of great significance to the improvement of the industry. Summary of the Invention

[0007] The purpose of the present invention is to solve the above problems and provide a nanofiber-particle composite reinforced high modulus polyurethane composite material and a preparation method thereof.

[0008] The nanofiber-particle composite reinforced high modulus polyurethane composite material described in the present invention is a polyurethane composite material prepared by a polyurethane composite material and reinforcing fibers through a corresponding composite production process; wherein the mass ratio of the polyurethane composite material to the reinforcing fibers is 1:(2.5-4); wherein the polyurethane composite material is a composite material formed by a component A resin, a component B curing agent and a component C reinforcing material in a mass ratio of 1:(0.82-1.18):(0.05-0.13); wherein the reinforcing fibers are surface-modified fibers obtained by surface-treating the reinforcing fibers with a surface treatment agent.

[0009] The polyurethane composite material comprises a polyurethane composition, wherein the A-component resin of the polyurethane composition is composed of a polyol, a chain extender, a solubilizer and a catalyst, the content of the chain extender, the solubilizer and the catalyst is 5-14%, 0.8-1.5% and 0.3-1.5% respectively, based on the total mass of the A-component; the polyol is at least one of saturated aliphatic polyester polyol, unsaturated aliphatic polyester polyol, polycaprolactone polyol, polyaromatic ester polyol, polyhybrid acid ester polyol or polyether polyol; the chain extender is at least one of ethylene glycol, butanediol, 1,6-ethylene glycol, 1,4-bis(2-hydroxyethoxy)benzene, glycerol, trimethylolpropane, pentaerythritol, 4,4'-methylenebis(2-chloroaniline), dimethylthiophenyl diamine, diethyl toluene diamine; the compatibilizer is at least one of organic silicon surfactant and organic zinc surfactant; and the catalyst is a heat-sensitive delayed catalyst.

[0010] The polyurethane composite material comprises a polyurethane composition, wherein the functionality of the A-component of the polyurethane composition is 2-6, and the hydroxyl value is 60-480 mgKOH / g.

[0011] The polyurethane composite material comprises a polyurethane composition, wherein the curing agent of the B-component of the polyurethane composition is at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, cyclohexane dimethylene diisocyanate, p-phenylene diisocyanate, benzene dimethylene diisocyanate, toluene diisocyanate trimer, hexamethylene diisocyanate trimer and hexamethylene diisocyanate biuret.

[0012] The polyurethane composite material comprises a polyurethane composition, wherein the reinforcing material of the C-component of the polyurethane composition is composed of nanofibers and nanoparticles; the nanofiber is at least one of cellulose nanocrystal, cellulose nanofibril, bacterial cellulose, electrospun cellulose nanofibril, polyamide nanofiber, polylactic acid nanofiber, polyvinylpyrrolidone nanofiber, polyethylene terephthalate nanofiber and nanoglass fiber; and the nanoparticle is at least one of silica nanoparticle, titanium dioxide nanoparticle, polyurea nanoparticle, polyurethane nanoparticle, ettringite nanoparticle and silicon carbide nanoparticle.

[0013] The polyurethane composite material comprises a polyurethane composition, wherein the modified nanofiber of the C-component of the polyurethane composition is obtained by surface modification using a polyamine reagent; the diameter of the modified nanofiber is in the range of 10-120 nm, and the aspect ratio is in the range of 3-30; the diameter of the modified nanoparticle is in the range of 30-200 nm; and the mass ratio of the nanofiber to the nanoparticle is 1: (0.7-1.2).

[0014] The reinforcing fiber in the polyurethane composite is obtained by modifying a conventional fiber with a silicone-based surface modifier; the conventional fiber is at least one of continuous glass fiber, glass fiber mat, bamboo fiber, carbon fiber, or polymer fiber.

[0015] The method for preparing the polyurethane composite comprises the following steps:

[0016] (1) mixing the resin of component A and the reinforcing material of component C in the polyurethane combination at a high speed under stirring at 40-60°C and simultaneously performing ultrasonic treatment for 2-10 min;

[0017] (2) uniformly mixing the treated mixture with the curing agent of component B within 30 min, and using a corresponding composite production process to composite the combination and the reinforcing fiber to prepare a composite material, and the high modulus polyurethane composite material can be obtained after curing at room temperature for 8-12 h.

[0018] The composite production process in step (2) of the preparation method is at least one of pultrusion molding, winding molding, injection molding, reaction injection molding, or injection compression molding.

[0019] The positive effects of the high modulus polyurethane composite material reinforced by nanofiber-particle composite and the preparation method thereof are:

[0020] Compared with the existing polyurethane composite material, the modified nanofiber and particle formed nanocomposite network structure are introduced in the present application to form a multi-scale topological structure between the polyurethane resin and the reinforcing fiber, and through the interaction force between the nanofiber and the particle, the nanofiber is combined near the nanoparticle, and through the higher capillary force and intermolecular force, the nanofiber is intertwined with each other and the nanoparticle forms a nanocomposite network structure with extremely high cohesion to further form a multiphase system with super stability in the composite material. Compared with the traditional single nanomaterial, the nanocomposite network structure formed by the nanomaterial has obvious enhancement in stability and interface adhesion capacity, and as the hub connecting the macroscopic reinforcing fiber and the resin matrix, the introduction of this structure can greatly improve the mechanical properties of the material.

[0021] Since the macroscopic reinforcing fibers and the nano-reinforcing materials are both subjected to corresponding surface treatment, the nano-reinforcing materials are distributed in the resin and the interface between the resin and the macroscopic fibers in the form of multi-scale topological structure, which greatly enhances the interaction between the macroscopic fibers and the resin matrix. When the material is subjected to external force, the matrix can be effectively protected from damage, and the generation and expansion of corresponding load silver streaks and shear bands are reduced; when the external load is larger, the nano-materials can change the expansion direction of the silver streaks and micro-cracks, and increase the ultimate load range of the material. When the external load exceeds the bearing range of the system, the propagation of the fracture zone and the breaking stress in the special micro-nano reinforcing structure with high cohesion needs to dissipate a large amount of energy, thereby effectively limiting the development of material damage, and enhancing the mechanical properties of the polyurethane composite material in terms of strength and toughness.

[0022] It can be seen that the high modulus polyurethane composite material provided by the application has clear action mechanism, simple production process, excellent performance, is suitable for large-scale production, and has important significance for the preparation of high-performance composite material components. Embodiment

[0023] The application will be further described in detail below with reference to specific examples.

[0024] Example 1: A high modulus polyurethane composite material reinforced by nano-fiber-particle composite, the preparation process is as follows

[0025] (1) Polyurethane combination material: A1 resin: 460 g of polytetramethylene ether polyol, 6 g of silicone surfactant, 30 g of 1,4-bis(2-hydroxyethoxy)benzene and 2.5 g of a heat-sensitive delayed catalyst. B1 curing agent: 411 g of toluene diisocyanate. C1 reinforcing component: 21.2 g of modified cellulose nanocrystals and 18.8 g of silica nanoparticles.

[0026] (2) The A1 component resin and the C1 component reinforcing material in the polyurethane combination material are mixed by high-speed stirring and ultrasonic treatment at 45°C for 5 min.

[0027] (3) The treated mixture is mixed uniformly with the B1 component curing agent within 30 min, and the combination material is compounded with 3300 g of modified continuous glass fibers to prepare a polyurethane composite material using a pultrusion molding production process. The high modulus polyurethane composite material can be obtained after curing at room temperature for 10 h.

[0028] Example 2: A high modulus polyurethane composite material reinforced by nano-fiber-particle composite, the preparation process is as follows

[0029] (1) Polyurethane formulation: A2 resin: 432 g polyadipate polyol, 6.3 g organic zinc surfactant, 45 g 4,4'-methylenebis(2-chloroaniline), and 1.5 g heat-sensitive delayed catalyst. B2 curing agent: 446 g isophorone diisocyanate. C2 reinforcing component: 24.8 g modified cellulose nanofibril and 20.2 g polyurea nanoparticle.

[0030] (2) The A2 component resin and C2 component reinforcing material in the polyurethane formulation were mixed by high-speed stirring at 40 °C and simultaneously subjected to ultrasonic treatment for 5 min.

[0031] (3) The treated mixture was mixed uniformly with the B2 component curing agent within 30 min, and the formulation was compounded with 3500 g of modified glass fiber mat using a pultrusion production process to prepare a polyurethane composite material. A high-modulus polyurethane composite material was obtained after curing at room temperature for 8 h.

[0032] Example 3: A nanofiber-particle composite-reinforced high-modulus polyurethane composite material was prepared as follows

[0033] (1) Polyurethane formulation: A3 resin: 448 g polycaprolactone polyol, 5.1 g silicone surfactant, 55 g trimethylolpropane, and 3 g heat-sensitive delayed catalyst. B3 curing agent: 430 g diphenylmethane diisocyanate. C3 reinforcing component: 28 g modified polyamide nanofiber and 23.2 g titanium dioxide nanoparticle.

[0034] (2) The A3 component resin and C3 component reinforcing material in the polyurethane formulation were mixed by high-speed stirring at 40 °C and simultaneously subjected to ultrasonic treatment for 6 min.

[0035] (3) The treated mixture was mixed uniformly with the B3 component curing agent within 30 min, and the formulation was compounded with 3770 g of modified polymer fiber using a filament winding production process to prepare a polyurethane composite material. A high-modulus polyurethane composite material was obtained after curing at room temperature for 9 h.

[0036] Example 4: A nanofiber-particle composite-reinforced high-modulus polyurethane composite material was prepared as follows

[0037] (1) Polyurethane formulation: A4 resin: 470 g polypropylene oxide polyol, 7 g organic zinc surfactant, 42 g dimethylthiuram disulfide, and 3.5 g heat-sensitive delayed catalyst. B4 curing agent: 438 g dicyclohexylmethane diisocyanate. C4 reinforcing component: 15.4 g modified polyvinylpyrrolidone nanofiber and 16.6 g polyurea nanoparticle.

[0038] (2) Mix A4 component resin and C4 component reinforcing material in polyurethane formulation at 55°C by high speed stirring and simultaneously perform ultrasonic treatment for 5 minutes.

[0039] (3) Mix the treated mixture with B4 component curing agent uniformly within 30 minutes, and use pultrusion production process to composite the formulation with 3800g modified carbon fiber to prepare polyurethane composite material. High modulus polyurethane composite material can be obtained after curing for 8 hours at room temperature.

[0040] Example 5: A nanofiber-particle composite reinforced high modulus polyurethane composite material is prepared as follows

[0041] (1) Polyurethane formulation: A5 resin: 445g polydiethylene glycol phthalate polyol, 4.5g silicone surfactant, 28g pentaerythritol and 2.9g heat sensitive delayed catalyst. B5 curing agent: 422g hexamethylene diisocyanate. C5 reinforcing component: 26.4g modified polyethylene terephthalate nanofiber and 26.4g silicon carbide nanoparticles.

[0042] (2) Mix A5 component resin and C5 component reinforcing material in polyurethane formulation at 50°C by high speed stirring and simultaneously perform ultrasonic treatment for 8 minutes.

[0043] (3) Mix the treated mixture with B5 component curing agent uniformly within 30 minutes, and use injection molding production process to composite the formulation with 3600g modified glass fiber mat to prepare polyurethane composite material. High modulus polyurethane composite material can be obtained after curing for 8 hours at room temperature.

[0044] Example 6: A nanofiber-particle composite reinforced high modulus polyurethane composite material is prepared as follows

[0045] (1) Polyurethane formulation: A6 resin: 448g dimer acid polyester polyol, 5.5g organic zinc surfactant, 50.8g diethyl toluene diamine and 4g heat sensitive delayed catalyst. B6 curing agent: 220g xylylene diisocyanate and 310g toluene diisocyanate trimer. C6 reinforcing component: 33.2g modified nanoglass fiber and 22.8g aluminite nanoparticles.

[0046] (2) Mix A6 component resin and C6 component reinforcing material in polyurethane formulation at 45°C by high speed stirring and simultaneously perform ultrasonic treatment for 10 minutes.

[0047] (3) The treated mixture is mixed with B6 component curing agent uniformly within 30 min, and the combined material is compounded with 4100 g of modified carbon fiber to prepare a polyurethane composite material using a filament winding production process. A high modulus polyurethane composite material is obtained after curing at room temperature for 9 h.

[0048] Example 7: A nanofiber-particle composite reinforced high modulus polyurethane composite material is prepared as follows

[0049] (1) Polyurethane combined material: A7 resin: 302 g of polytetramethylene ether glycol, 205 g of polypropylene oxide polyol, 4.6 g of organic zinc surfactant, 38.4 g of trimethylolpropane, and 3.3 g of a heat-sensitive delayed catalyst. B7 curing agent: 233 g of p-phenylene diisocyanate and 344 g of hexamethylene diisocyanate trimer. C7 reinforcing component: 29.7 g of modified cellulose nanofibrils and 25.3 g of silica nanoparticles.

[0050] (2) The A7 component resin and the C7 component reinforcing material in the polyurethane combined material are mixed by high-speed stirring and ultrasonic treatment at 50°C for 8 min.

[0051] (3) The treated mixture is mixed with B7 component curing agent uniformly within 30 min, and the combined material is compounded with 3900 g of modified continuous glass fiber to prepare a polyurethane composite material using an injection molding production process. A high modulus polyurethane composite material is obtained after curing at room temperature for 9 h.

[0052] Example 8: A nanofiber-particle composite reinforced high modulus polyurethane composite material is prepared as follows

[0053] (1) Polyurethane combined material: A8 resin: 310 g of polypropylene oxide polyol, 167 g of polycaprolactone polyol, 4.2 g of silicone surfactant, 36 g of triisopropanolamine, and 3 g of a heat-sensitive delayed catalyst. B8 curing agent: 430 g of cyclohexane dimethylene diisocyanate. C8 reinforcing component: 34.5 g of modified polyamide nanofiber and 30.5 g of polyurea nanoparticle.

[0054] (2) The A8 component resin and the C8 component reinforcing material in the polyurethane combined material are mixed by high-speed stirring and ultrasonic treatment at 45°C for 10 min.

[0055] (3) The treated mixture is mixed with B8 component curing agent uniformly within 30 min, and the combined material is compounded with 4060 g of modified bamboo fiber to prepare a polyurethane composite material using a pultrusion production process. A high modulus polyurethane composite material is obtained after curing at room temperature for 8 h.

[0056] Comparative Example 1: A polyurethane composite material without nanomaterial reinforcement

[0057] (1) Mix the A1 component resin with the B1 component curing agent uniformly, and use the pultrusion production process to compound the combined material with 3300 g of modified continuous glass fiber to prepare a polyurethane composite material. After 10 h of curing at room temperature, a polyurethane composite material without nano-material reinforcement is obtained.

[0058] Comparative Example 2: Polyurethane composite material with unmodified nano-fiber and reinforcing fiber

[0059] (1) Polyurethane combined material: A3 resin and B3 curing agent as above. C9 reinforcing component: 28 g of unmodified polyamide nano-fiber and 23.2 g of titanium dioxide nano-particle.

[0060] (2) Mix the A3 component resin in the polyurethane combined material with the C9 component reinforcing material at 40°C under high-speed stirring and simultaneously perform ultrasonic treatment for 6 min.

[0061] (3) Mix the treated mixture with the B3 component curing agent uniformly within 30 min, and use the winding molding production process to compound the combined material with 3770 g of unmodified polymer fiber to prepare a polyurethane composite material. After 9 h of curing at room temperature, a polyurethane composite material with unmodified nano-fiber and reinforcing fiber is obtained.

[0062] Comparative Example 3: Pure nano-fiber reinforced polyurethane composite material

[0063] (1) Polyurethane combined material: A4 resin and B4 curing agent as above. C10 reinforcing component: 32 g of modified polyvinylpyrrolidone nano-fiber.

[0064] (2) Mix the A4 component resin in the polyurethane combined material with the C10 component reinforcing material at 55°C under high-speed stirring and simultaneously perform ultrasonic treatment for 5 min.

[0065] (3) Mix the treated mixture with the B4 component curing agent uniformly within 30 min, and use the pultrusion production process to compound the combined material with 3800 g of modified carbon fiber to prepare a polyurethane composite material. After 8 h of curing at room temperature, a pure nano-fiber reinforced polyurethane composite material is obtained.

[0066] Comparative Example 4: Pure nano-particle reinforced polyurethane composite material

[0067] (1) Polyurethane combined material: A4 resin and B4 curing agent as above. C11 reinforcing component: 32 g of polyurethane nano-particle.

[0068] (2) Mix the A4 component resin in the polyurethane combined material with the C11 component reinforcing material at 55°C under high-speed stirring and simultaneously perform ultrasonic treatment for 5 min.

[0069] (3) The treated mixture is mixed with B4 component curing agent uniformly within 30 min, and the combined material is compounded with 3800 g modified carbon fiber to prepare polyurethane composite material using pultrusion production process. The pure nano-particle reinforced polyurethane composite material can be obtained after curing at room temperature for 8 h.

[0070] Comparative Example 5: Nano-fiber-particle composite reinforced polyurethane composite material

[0071] (1) Polyurethane combined material: A7 resin and B7 curing agent are the same as above. C12 reinforcing component: 44 g modified cellulose nanofibril and 11 g silica nanoparticle.

[0072] (2) The A7 component resin in the polyurethane combined material and the C12 component reinforcing material are mixed by high-speed stirring at 50°C and ultrasonic treatment is simultaneously performed for 8 min.

[0073] (3) The treated mixture is mixed with B7 component curing agent uniformly within 30 min, and the combined material is compounded with 3900 g modified continuous glass fiber to prepare polyurethane composite material using injection molding production process. The high modulus polyurethane composite material can be obtained after curing at room temperature for 9 h.

[0074] Comparative Example 6: Nano-fiber-particle composite reinforced polyurethane composite material

[0075] (1) Polyurethane combined material: A7 resin and B7 curing agent are the same as above. C13 reinforcing component: 11 g modified cellulose nanofibril and 44 g silica nanoparticle.

[0076] (2) The A7 component resin in the polyurethane combined material and the C13 component reinforcing material are mixed by high-speed stirring at 50°C and ultrasonic treatment is simultaneously performed for 8 min.

[0077] (3) The treated mixture is mixed with B7 component curing agent uniformly within 30 min, and the combined material is compounded with 3900 g modified continuous glass fiber to prepare polyurethane composite material using injection molding production process. The high modulus polyurethane composite material can be obtained after curing at room temperature for 9 h.

[0078] Effect description:

[0079] The nano-fiber-particle composite reinforced high modulus polyurethane composite material prepared in Examples 1-8 in the present application and the polyurethane composite material prepared in Comparative Examples 1-6 are compared in performance test.

[0080] The mechanical properties and durability performance tests were carried out according to GB / T 2567-2008 "Resin cast body performance test method" and GB / T 9640-2008 "Soft and hard foam polymeric material accelerated aging test method". Among them, the ultraviolet aging test simulates the natural ultraviolet aging effect of the product according to GB / T 16422.3-2014 Type 2 (UVB-313) lamp (Method C), and the exposure cycle is 1000h; the salt spray aging is carried out according to the neutral salt spray test (NSS) method specified in GB / T 10125-2012, and the aging is 1000h; the damp heat aging is carried out according to the damp heat test method specified in GB / T 2573-2008, and the aging is 720h.

[0081] The relevant test results are arranged in Table 1:

[0082] Table 1 Performance test results of polyurethane composite materials

[0083] Sample Machine Direction Tensile Strength (MPa) Machine Direction Tensile Modulus (GPa) Machine Direction Flexural Strength (MPa) Machine Direction Flexural Modulus (GPa) Machine Direction Compressive Strength (MPa) Ultraviolet Aging Tensile Strength Retention (%) Salt Spray Aging Tensile Strength Retention (%) Hygrothermal Aging Tensile Strength Retention (%) Example 1 982 45.8 1426 51.2 692 96.3 95.2 94.3 Example 2 1060 48.2 1538 54.3 746 95.4 94.5 92.2 Example 3 996 46.9 1457 52.5 721 97.6 96.3 93.7 Example 4 973 44.8 1420 50.6 695 94.5 94.4 94.6 Example 5 1010 47.6 1573 56.3 773 97.0 95.8 95.3 Example 6 986 46.1 1480 53.1 729 95.6 93.6 91.8 Example 7 1053 47.9 1551 55.7 765 96.4 93.5 92.9 Example 8 1005 47.1 1496 53.6 736 95.5 94.7 93.4 Comparative Example 1 588 23.1 886 31.8 432 91.5 88.3 85.7 Comparative Example 2 775 30.5 1154 41.4 562 92.2 87.5 86.6 Comparative Example 3 682 26.8 964 34.6 470 89.7 89.2 84.3 Comparative Example 4 653 25.7 955 32.3 439 91.8 91.1 89.2 Comparative Example 5 735 28.9 999 35.9 488 88.7 89.7 86.4 Comparative Example 6 786 31.0 1054 37.9 516 92.5 90.6 90.1

[0084] As can be seen from the data in Table 1, the polyurethane composite materials prepared in the examples have very excellent mechanical properties and durability performance, and have high strength and modulus in all directions, especially high bending strength and modulus, which is of great significance for the deflection and deformation control of polyurethane composite materials in actual application.

[0085] In Comparative Example 1, due to the lack of nanomaterial as a reinforcing material in the system, the fracture stress and the transmission of microcracks and interface slip are easy, and the mechanical properties are obviously lower than those of the examples. In Comparative Example 2, unmodified nanomaterial and reinforcing fibers are used, and because the interface action of the unmodified material is significantly reduced, the composite network construction of the nanomaterial and the interface distribution with the reinforcing fibers are both greatly changed, resulting in a certain decrease in strength. In Comparative Examples 3 and 4, only one kind of nanomaterial is used as a micro-reinforcing material, and because the cohesive force of the reinforcing system formed by a single nanomaterial is obviously lower than that of the composite network structure formed by nanofiber-particle, the reinforcing effect is also reduced. As can be seen from Comparative Examples 5 and 6, the ratio of nanofiber and particle must be within a certain range to form a reinforced composite network structure under ultrasonic conditions in a short time, and when the ratio of the two materials is outside the recommended ratio, the reinforcing effect is obviously reduced. As can be seen from the durability data, for ultraviolet, salt spray and damp heat aging, the main performance is due to the resin itself, so the difference between the comparative examples and the examples is not very obvious, but the introduction of the nanoreinforced system still brings a certain improvement in durability performance due to the improvement of the overall performance of the composite material.

[0086] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Any simple modification, equivalent change and modification of the above embodiment without departing from the technical solution content of the present application and according to the technical essence of the present application still belongs to the scope of the technical solution of the present application.

Claims

1. A nanofiber-particle composite reinforced high modulus polyurethane composite material, characterized by, The polyurethane composite material is prepared from a polyurethane compound and reinforcing fibers through a corresponding composite production process; wherein the mass ratio of the polyurethane compound and the reinforcing fibers is 1:(2.5-4); wherein the polyurethane compound is formed from a component A resin, a component B curing agent and a component C reinforcing material in a mass ratio of 1:(0.82-1.08):(0.05-0.13); wherein the reinforcing fibers are surface-modified fibers obtained by surface treatment of the reinforcing fibers with a surface treatment agent; wherein the component C reinforcing material in the polyurethane compound is composed of modified nanofibers and nanoparticles, the modified nanofibers are obtained by surface modification of nanofibers using a polyamine reagent, and the mass ratio of the modified nanofibers and the nanoparticles is 1:(0.7-1.2).

2. A polyurethane composite as claimed in claim 1, characterized in that The component A resin in the polyurethane compound is composed of a polyol, a chain extender, a solubilizer and a catalyst, wherein the content of the chain extender, the solubilizer and the catalyst is 5-14%, 0.8-1.5% and 0.1-1.5% respectively, based on the total mass of the component A; wherein the polyol is at least one of saturated aliphatic polyester polyol, unsaturated aliphatic polyester polyol, polycaprolactone polyol, polyaromatic ester polyol, polyhybrid acid ester polyol or polyether polyol; wherein the chain extender is at least one of ethylene glycol, butanediol, 1,6-ethylene glycol, 1,4-bis(2-hydroxyethoxy)benzene, glycerol, trimethylolpropane, pentaerythritol, 4,4'-methylenebis(2-chloroaniline), dimethylthiophenyl diamine, diethyl toluene diamine or triisopropanolamine; wherein the solubilizer is at least one of organic silicon surfactant and organic zinc surfactant; wherein the catalyst is a heat-sensitive delayed catalyst.

3. A polyurethane composite as claimed in claim 2, characterised in that The functionality of the component A in the polyurethane compound is 2-6, and the hydroxyl value is 60-480 mgKOH / g.

4. A polyurethane composite as claimed in claim 1, wherein The component B curing agent in the polyurethane compound is composed of at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, cyclohexane dimethylene diisocyanate, p-phenylene diisocyanate, benzene dimethylene diisocyanate, toluene diisocyanate trimer, hexamethylene diisocyanate trimer and hexamethylene diisocyanate biuret.

5. A polyurethane composite as claimed in claim 1, wherein The modified nanofibers in the component C reinforcing material in the polyurethane compound are at least one of modified cellulose nanocrystals, modified cellulose nanofibrils, modified bacterial cellulose, modified electrospun cellulose nanofibrils, modified polyamide nanofibers, modified polylactic acid nanofibers, modified polyvinylpyrrolidone nanofibers, modified polyethylene terephthalate nanofibers and modified nanoglass fibers; and the nanoparticles are at least one of silica nanoparticles, titanium dioxide nanoparticles, polyurea nanoparticles, polyurethane nanoparticles, ettringite nanoparticles and silicon carbide nanoparticles.

6. A polyurethane composite as claimed in claim 5, characterised in that The diameter of the modified nanofiber in the polyurethane composite C component is in the range of 10-120 nm, and the aspect ratio is in the range of 3-30; the diameter of the nanoparticle is in the range of 30-200 nm.

7. A polyurethane composite as claimed in claim 1, wherein The reinforcing fiber is obtained by modifying a conventional fiber with an organosilicon surface modifier; the conventional fiber is at least one of modified continuous glass fiber, modified glass fiber mat, modified bamboo fiber, modified carbon fiber, or modified polymer fiber.

8. The method of claim 1, wherein the polyurethane composite is prepared by mixing the polyurethane prepolymer, the filler, and the curing agent. The method comprises the following steps: (1) mixing the resin of component A and the reinforcing material of component C of the polyurethane composite at 40-60°C by high-speed stirring and simultaneously performing ultrasonic treatment for 2-10 min; (2) uniformly mixing the treated mixture with the curing agent of component B within 30 min, and using a corresponding composite production process to composite the composite material with the reinforcing fiber to prepare a high-modulus polyurethane composite material, which can be cured at room temperature for 8-12 h.

9. The method for preparing a polyurethane composite material according to claim 8, wherein the composite production process is at least one of pultrusion, winding, injection molding, reaction injection molding, or injection compression molding.

10. The application of the polyurethane composite material according to claim 1 as a railing, a sleeper, a support, a bridge, a wall, or a building.