A continuous fiber reinforced polyurethane composite material and its preparation method

Abstract

The present invention relates to the technical field of composite materials, and discloses a continuous fiber reinforced polyurethane composite material and a preparation method thereof; polyether polyol, chain extender, catalyst, foam stabilizer and defoamer are mixed evenly to obtain a resin stock solution, and shear thickening glue A is added and mixed evenly to obtain a compound resin stock solution; shear thickening glue B is coated on the surface of a secondary modified UHMWPE fabric and baked to obtain a composite UHMWPE fabric; two pieces of the composite UHMWPE fabric with the side not coated with shear thickening glue B facing inwards are respectively placed on the top and bottom surfaces of a mold, and the compound resin stock solution and isocyanate are continuously and statically mixed and injected into the mold, and heated and cured to be continuously formed to obtain a polyurethane composite material.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and particularly to a continuous fiber reinforced polyurethane composite material and a preparation method thereof. Background Art

[0002] With the continuous development of science and technology, cars have entered every household as a means of transportation in the new era. However, the accompanying problems are road congestion, resource consumption, exhaust pollution, etc. For the purpose of environmental protection and energy conservation, the lightweight transformation of cars has become a trend in the development of the world's automotive industry. The reason is that reducing the mass of cars can reduce fuel consumption and improve fuel efficiency, thereby reducing resource consumption and exhaust pollution. On the premise of ensuring the structural strength and safety performance of cars, achieving the lightweight of cars has become an increasingly concerned topic.

[0003] Therefore, the present invention aims to achieve the goal of lightweighting cars on the premise of ensuring the structural strength and safety performance of cars by preparing a polyurethane composite material with high strength and low mass. Summary of the Invention

[0004] The purpose of the present invention is to provide a continuous fiber reinforced polyurethane composite material and a preparation method thereof to solve the problems raised in the above background art.

[0005] To solve the above technical problems, the present invention provides the following technical solutions:

[0006] A preparation method of a continuous fiber reinforced polyurethane composite material, comprising the following steps:

[0007] S1: Immerse the zinc oxide-dopamine modified UHMWPE fabric in a sodium hypochlorite solution with a concentration of 0.2 - 0.3 mol / L and a pH of 3.5 - 4, stir at 60 - 65 °C for 30 - 45 min, wash, and dry to obtain a chlorinated UHMWPE fabric; add hydroxyethyl methacrylate, cuprous chloride, copper chloride, and 2,2'-bipyridine to an aqueous methanol solution, stir evenly, immerse the chlorinated UHMWPE fabric therein, and react at 60 - 65 °C in a nitrogen atmosphere for 2 - 3 h, wash, and dry to obtain a secondarily modified UHMWPE fabric;

[0008] S2: Disperse starch in deionized water, sequentially add sodium carbonate, sodium trimetaphosphate, and sodium hydroxide, react at 50 - 55 °C for 24 - 28 h, adjust the pH to 6.5 - 7.5, wash, filter, and dry to obtain a crosslinking agent; mix hydroxy silicone oil A and the crosslinking agent evenly, add boric acid, and react at 160 - 165 °C for 2 - 3 h to obtain shear thickening gum A; react hydroxy silicone oil B and boric acid at 160 - 165 °C for 2 - 3 h to obtain shear thickening gum B;

[0009] S3: Mix polyether polyol, chain extender, catalyst, foam stabilizer and defoamer evenly to obtain a resin stock solution. Add shear thickening gum A and thermally expandable microspheres and mix evenly to obtain a compound resin stock solution. Coat shear thickening gum B on the surface of the secondary modified UHMWPE fabric, and bake it in an environment of 160 - 165 °C for 30 - 45 min to obtain a composite UHMWPE fabric. Take two pieces of the composite UHMWPE fabric with the side not coated with shear thickening gum B facing inwards, place them on the top and bottom surfaces of the mold respectively, continuously and statically mix and inject the compound resin stock solution and isocyanate into the mold, and heat and cure continuously to form a polyurethane composite material.

[0010] Further, the zinc oxide - dopamine modified UHMWPE fabric is prepared as follows:

[0011] Immerse the UHMWPE fabric in a dopamine solution and stir at room temperature for 18 - 24 h to obtain a dopamine - modified UHMWPE fabric. React a zinc acetate dihydrate - ethanol solution and a sodium hydroxide - ethanol solution at 65 - 70 °C for 2 - 3 h, immerse the dopamine - modified UHMWPE fabric in it for 15 - 20 min, anneal at 100 °C, and repeat the immersion and annealing operations 1 - 3 times to obtain a pretreated UHMWPE fabric. Mix zinc nitrate hexahydrate and hexamethylenetetramine evenly and dissolve them in water. Immerse the pretreated UHMWPE fabric in it, add polyethyleneimine, react at 75 - 80 °C for 1 - 2 h, add ammonia water to adjust the pH, and react at 85 - 95 °C for 1 - 2 h, wash and dry to obtain the zinc oxide - dopamine modified UHMWPE fabric.

[0012] Further, the dopamine solution is a mixed solution of a tris - (hydroxymethyl) aminomethane solution with a concentration of 1.2 - 1.4 g / L and a dopamine hydrochloride solution with a concentration of 2 g / L, and the pH is 8.5. In the zinc acetate dihydrate - ethanol solution, the added amount of zinc acetate dihydrate is 1.4 - 1.6 mmol, and in the sodium hydroxide - ethanol solution, the added amount of sodium hydroxide is 1 - 1.2 mmol. The mass ratio of zinc nitrate hexahydrate to hexamethylenetetramine is 0.3:0.14, the added amount of polyethyleneimine is 1 - 5 mmol, and ammonia water adjusts the pH to 11.2 - 11.6.

[0013] Further, in the secondary modified UHMWPE fabric, the mass ratio of 2 - hydroxyethyl methacrylate: cuprous chloride: copper chloride: 2,2'-bipyridine is (130 - 150):(1 - 1.15):(0.34 - 0.39):(3.12 - 3.6), and the volume ratio of the methanol aqueous solution is 1:1.

[0014] Further, in the cross - linker, the mass ratio of starch: sodium carbonate: sodium trimetaphosphate: sodium hydroxide is (100 - 120):(3 - 3.6):(3.3 - 4):(1.1 - 1.3).

[0015] Further, in the shear thickening glue A, the viscosity of the hydroxyl silicone oil A is 2000-3000 cst, the mass ratio of the hydroxyl silicone oil A to boric acid is 100:(0.4-0.5), and the mass ratio of the hydroxyl silicone oil A to the cross-linking agent is (2-5):(5-8).

[0016] Further, in the shear thickening glue B, the viscosity of the hydroxyl silicone oil B is 100-200 cst, and the mass ratio of the hydroxyl silicone oil B to

[0017] boric acid is 100:(1-1.2).

[0018] Further, the mass ratio of the resin stock solution to the isocyanate is 100:(92.4-96.6); in the compound resin stock solution, by mass parts, 80-100 parts of the resin stock solution and 15-20 parts of the shear thickening glue A; the curing temperature is 130-135 °C, and the aging temperature is 20-25 °C.

[0019] Further, in the resin stock solution, by mass parts, 80-100 parts of polyether polyol, 1-5 parts of chain extender, 1-2 parts of catalyst, 0.5-2 parts of foam stabilizer, and 15-25 parts of defoamer.

[0020] Further, the molecular weight of the polyether polyol is 1000-2000, the chain extender is ethylene glycol, the foam stabilizer is silicone oil, the catalyst is a tertiary amine catalyst, and the defoamer is a triol with a molecular weight of 400.

[0021] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0022] The present invention forms a layer of dopamine film on the surface of the UHMWPE fabric by the method of oxidative self-polymerization, then deposits a seed layer (a uniform zinc oxide coating) by the sol-gel method and rapid heat treatment, and then makes zinc oxide whiskers grow in-situ on the surface of the UHMWPE fabric by the hydrothermal synthesis method to form a zinc oxide nanoarray. In order to make zinc oxide preferentially grow along the direction perpendicular to the surface of the UHMWPE fabric and increase the mechanical interlocking effect between zinc oxide and the polyurethane matrix, polyethyleneimine is added as a capping agent. On the one hand, its side chain contains a large number of amino groups, which can be protonated in the solution to be positively charged and adsorbed on the negatively charged side of the zinc oxide whiskers by electrostatic adsorption, achieving the effect of inhibiting the lateral growth of zinc oxide; on the other hand, it can complex with the free zinc ions in the solution, inhibit the combination of zinc ions and hydroxide ions, prevent the growth of zinc oxide in the water medium, and improve the solubility of zinc ions.

[0023] Although the addition of polyethyleneimine can effectively guide the growth of zinc oxide into vertical zinc oxide nanoarrays on the surface of UHMWPE fabrics, form a mechanical interlocking structure with the polyurethane matrix, and increase the bonding strength at the interface between the UHMWPE fabric and the polyurethane matrix, it inhibits the lateral growth of zinc oxide, resulting in smaller diameters of the grown zinc oxide whiskers and a decrease in the bonding strength between the zinc oxide whiskers and the UHMWPE fabric. The zinc oxide nanoarrays formed on the surface of the UHMWPE fabric also reduce the surface wettability, making it difficult for the polyurethane matrix to penetrate, and the strength of the mechanical interlocking structure is relatively low.

[0024] To solve the above accompanying problems, in the present invention, after adding polyethyleneimine and reacting for a period of time, ammonia water is added to increase the pH value of the reaction solution, which reduces the degree of protonation of polyethyleneimine in the solution, decreases its positive charge density in the solution, and reduces the electrostatic adsorption on the side of the zinc oxide whiskers. Since there are fewer hydroxide particles adsorbed on the side and fewer nucleation sites, a large number of newly formed zinc oxide nanocrystallites grow on the side of the zinc oxide whiskers; compared with the method of directly increasing the whisker diameter to solve the problem of the bonding strength between the whiskers and the UHMWPE fabric, the whiskers prepared in the present invention with vertical whiskers as the trunk and side-grown whiskers as the branches can enhance both the mechanical interlocking with the polyurethane matrix and the bonding strength with the UHMWPE fabric.

[0025] In the present invention, by subjecting the zinc oxide-dopamine modified UHMWPE fabric to a secondary modification, hydroxyethyl methacrylate is grafted onto the surface of the UHMWPE fabric. On the one hand, it enhances the interfacial wettability between the UHMWPE fabric and the polyurethane. On the other hand, during the mold closing and foaming process, part of the isocyanate reacts with the hydroxyl group, enhancing the interfacial bonding force between the UHMWPE fabric and the polyurethane; greatly improving the mechanical strength of the polyurethane composite.

[0026] In the present invention, a low-viscosity shear thickening gel is prepared from low-viscosity hydroxy silicone oil and boric acid. Coating it on the surface of the UHMWPE fabric can fill the gaps between the fabric yarns and fibers. On the one hand, it prevents the polyurethane foaming stock solution from penetrating through the fabric gaps during the foaming process, greatly improving the stability of the "sandwich" structure; on the other hand, the hydroxyl groups at both ends of the low-viscosity shear thickening gel form new covalent bonds with the hydroxyl groups of hydroxyethyl methacrylate, enhancing the entanglement effect, inhibiting the deformation of the shear thickening gel, and enhancing the mechanical properties of the outer contact surface.

[0027] The present invention modifies starch with a compound solution of sodium carbonate, sodium tripolyphosphate, and sodium hydroxide to prepare a crosslinking agent with low particle swelling and rupture, and mixes it with a shear thickening gum to achieve the effect of reinforcing the shear thickening gum. During the preparation process, boric acid on the crosslinking agent can become a "bridge" between the crosslinking agent and hydroxyl silicone oil through hydrogen bonding or esterification reaction. At the same time, boron elements on the surface of the crosslinking agent and oxygen elements in the shear thickening gum, as well as oxygen elements on the surface of the crosslinking agent and boron elements in the shear thickening gum, form dynamic crosslinks, greatly enhancing the shear thickening effect of the reinforced shear thickening gum and improving the intermolecular compatibility. The self-made shear thickening gum A and polyurethane composite resin are filled between two pieces of UHMWPE fabric to form a polyurethane composite material with high strength, light weight, and good impact resistance. Detailed implementation mode

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0029] It should be noted that there are no special restrictions on the purchase manufacturers of all raw materials involved in the present invention. Exemplarily, the UHMWPE fabric is of plain weave type, the molecular weight of polyethylene is 3 million - 4 million, and the fabric surface density is 240 g / m 2 ; Hydroxyl silicone oil A has a viscosity of 2000 cst, and hydroxyl silicone oil B has a viscosity of 100 cst; The molecular weight of polyethyleneimine is 600; The polyether polyol has a CAS number of 9003 - 11 - 6 and a molecular weight of 2000; The remaining raw materials are all commercially available.

[0030] In the following examples, the dopamine solution is prepared as follows: A solution of tris(hydroxymethyl)aminomethane with a concentration of 1.2 g / L and a dopamine hydrochloride solution with a concentration of 2 g / L are mixed evenly, and the pH is adjusted to 8.5 to obtain the dopamine solution.

[0031] Example 1: A preparation method of a continuous fiber-reinforced polyurethane composite material: S1: Immerse the UHMWPE fabric in a dopamine solution and stir at room temperature for 18 h to obtain dopamine-modified UHMWPE fabric; dissolve 1.4 mmol of zinc acetate dihydrate in an ethanol solution, dissolve 1 mmol of sodium hydroxide in an ethanol solution, react at 65 °C for 2 h, immerse the dopamine-modified UHMWPE fabric therein for 15 min, anneal at 100 °C, and repeat the immersion and annealing operations 3 times to obtain pretreated UHMWPE fabric; mix 3 g of zinc nitrate hexahydrate and 1.4 g of hexamethylenetetramine evenly and dissolve them in water, immerse the pretreated UHMWPE fabric therein, add 1 mmol of polyethyleneimine, react at 75 °C for 1 h, add ammonia water to adjust the pH to 11.2, react at 85 °C for 1 h, wash and dry to obtain zinc oxide-dopamine-modified UHMWPE fabric;

[0032] S2: Immerse the zinc oxide-dopamine-modified UHMWPE fabric in a sodium hypochlorite solution with a concentration of 0.2 mol / L and a pH of 3.5, stir at 60 °C for 30 min, wash and dry to obtain chlorinated UHMWPE fabric; add 100 g of 2-hydroxyethyl methacrylate, 1 g of cuprous chloride, 0.34 g of copper chloride, and 3.12 g of 2,2'-bipyridine to a mixed solution of 100 mL of methanol and 100 mL of water, stir evenly, immerse the chlorinated UHMWPE fabric therein, react at 60 °C for 2 h under a nitrogen atmosphere, wash and dry to obtain secondarily modified UHMWPE fabric;

[0033] S3: Disperse 100 g of starch in deionized water, sequentially add 3 g of sodium carbonate, 3.3 g of sodium trimetaphosphate, and 1.1 g of sodium hydroxide, react at 50 °C for 24 h, adjust the pH to 6.5, wash, filter, and dry to obtain a crosslinking agent; mix 10 g of hydroxyl silicone oil A and 40 g of the crosslinking agent evenly, add 0.04 g of boric acid, and react at 160 °C for 2 h to obtain shear thickening gum A; react 10 g of hydroxyl silicone oil B and 0.1 g of boric acid at 160 °C for 2 h to obtain shear thickening gum B;

[0034] S4: Mix 100 g of polyether polyol, 2 g of chain extender, 1 g of catalyst, 0.5 g of foam stabilizer, and 20 g of defoamer evenly to obtain a resin stock solution, add 15 g of shear thickening gum A to 100 g of the resin stock solution and mix evenly to obtain a compounded resin stock solution; coat shear thickening gum B on the surface of the secondarily modified UHMWPE fabric, place it in an environment of 160 °C and bake for 30 min to obtain a composite UHMWPE fabric; take two pieces of the composite UHMWPE fabric with the side without coated shear thickening gum B facing inward, place them on the top and bottom surfaces of the mold respectively, continuously and statically mix and inject the compounded resin stock solution and isocyanate into the mold, and heat and cure continuously to form a polyurethane composite material.

[0035] Example 2: A preparation method of a continuous fiber-reinforced polyurethane composite material: S1: Immerse the UHMWPE fabric in a dopamine solution and stir at room temperature for 18 h to obtain dopamine-modified UHMWPE fabric; dissolve 1.4 mmol of zinc acetate dihydrate in an ethanol solution, dissolve 1 mmol of sodium hydroxide in an ethanol solution, react at 65 °C for 2 h, immerse the dopamine-modified UHMWPE fabric therein for 15 min, anneal at 100 °C, and repeat the immersion and annealing operations 3 times to obtain pretreated UHMWPE fabric; mix 3 g of zinc nitrate hexahydrate and 1.4 g of hexamethylenetetramine evenly and dissolve them in water, immerse the pretreated UHMWPE fabric therein, add 5 mmol of polyethyleneimine, react at 75 °C for 1 h, add ammonia water to adjust the pH to 11.2, react at 85 °C for 1 h, wash and dry to obtain zinc oxide-dopamine-modified UHMWPE fabric;

[0036] S2: Immerse the zinc oxide-dopamine-modified UHMWPE fabric in a sodium hypochlorite solution with a concentration of 0.2 mol / L and a pH of 3.5, stir at 60 °C for 30 min, wash and dry to obtain chlorinated UHMWPE fabric; add 100 g of 2-hydroxyethyl methacrylate, 1 g of cuprous chloride, 0.34 g of copper chloride, and 3.12 g of 2,2'-bipyridine to a mixed solution of 100 mL of methanol and 100 mL of water, stir evenly, immerse the chlorinated UHMWPE fabric therein, react at 60 °C for 2 h under a nitrogen atmosphere, wash and dry to obtain secondary-modified UHMWPE fabric;

[0037] S3: Disperse 100 g of starch in deionized water, sequentially add 3 g of sodium carbonate, 3.3 g of sodium trimetaphosphate, and 1.1 g of sodium hydroxide, react at 50 °C for 24 h, adjust the pH to 6.5, wash, filter and dry to obtain a crosslinking agent; mix 20 g of hydroxy silicone oil A and 30 g of the crosslinking agent evenly, add 0.08 g of boric acid, and react at 160 °C for 2 h to obtain shear thickening gum A; react 10 g of hydroxy silicone oil B and 0.1 g of boric acid at 160 °C for 2 h to obtain shear thickening gum B;

[0038] S4: Mix 100 g of polyether polyol, 2 g of chain extender, 1 g of catalyst, 0.5 g of foam stabilizer, and 20 g of defoamer evenly to obtain a resin stock solution, add 18 g of shear thickening gum A to 100 g of the resin stock solution and mix evenly to obtain a compound resin stock solution; coat shear thickening gum B on the surface of the secondary-modified UHMWPE fabric, place it in an environment of 160 °C and bake for 30 min to obtain a composite UHMWPE fabric; take two pieces of the composite UHMWPE fabric with the side without coated shear thickening gum B facing inward, place them on the top and bottom surfaces of the mold respectively, continuously and statically mix the compound resin stock solution and isocyanate and inject them into the mold, heat and cure continuously to form a polyurethane composite material.

[0039] Example 3: A preparation method of a continuous fiber-reinforced polyurethane composite material: S1: Immerse the UHMWPE fabric in a dopamine solution and stir at room temperature for 18 h to obtain dopamine-modified UHMWPE fabric; dissolve 1.4 mmol of zinc acetate dihydrate in an ethanol solution, dissolve 1 mmol of sodium hydroxide in an ethanol solution and react at 65 °C for 2 h, immerse the dopamine-modified UHMWPE fabric in it for 15 min, anneal at 100 °C, and repeat the immersion and annealing operations 3 times to obtain pretreated UHMWPE fabric; mix 3 g of zinc nitrate hexahydrate and 1.4 g of hexamethylenetetramine evenly and dissolve in water, immerse the pretreated UHMWPE fabric in it, add 3 mmol of polyethyleneimine, react at 75 °C for 1 h, add ammonia water to adjust the pH to 11.2, react at 85 °C for 1 h, wash and dry to obtain zinc oxide-dopamine-modified UHMWPE fabric;

[0040] S2: Immerse the zinc oxide-dopamine-modified UHMWPE fabric in a sodium hypochlorite solution with a concentration of 0.2 mol / L and a pH of 3.5, stir at 60 °C for 30 min, wash and dry to obtain chlorinated UHMWPE fabric; add 100 g of 2-hydroxyethyl methacrylate, 1 g of copper(I) chloride, 0.34 g of copper(II) chloride, and 3.12 g of 2,2'-bipyridine to a mixed solution of 100 mL of methanol and 100 mL of water, stir evenly, immerse the chlorinated UHMWPE fabric in it, react at 60 °C under a nitrogen atmosphere for 2 h, wash and dry to obtain secondary-modified UHMWPE fabric;

[0041] S3: Disperse 100 g of starch in deionized water, sequentially add 3 g of sodium carbonate, 3.3 g of sodium trimetaphosphate, and 1.1 g of sodium hydroxide, react at 50 °C for 24 h, adjust the pH to 6.5, wash, filter, and dry to obtain a crosslinking agent; mix 25 g of hydroxy silicone oil A and 25 g of the crosslinking agent evenly, add 0.1 g of boric acid, and react at 160 °C for 2 h to obtain shear thickening gum A; react 10 g of hydroxy silicone oil B and 0.1 g of boric acid at 160 °C for 2 h to obtain shear thickening gum B;

[0042] S4: Mix 100 g of polyether polyol, 2 g of chain extender, 1 g of catalyst, 0.5 g of foam stabilizer, and 20 g of defoamer evenly to obtain a resin stock solution, add 20 g of shear thickening gum A to 100 g of the resin stock solution and mix evenly to obtain a compounded resin stock solution; coat shear thickening gum B on the surface of the secondary-modified UHMWPE fabric, place it in an environment of 160 °C and bake for 30 min to obtain a composite UHMWPE fabric; take two pieces of the composite UHMWPE fabric with the side without coated shear thickening gum B facing inwards, place them on the top and bottom surfaces of the mold respectively, continuously and statically mix and inject the compounded resin stock solution and isocyanate into the mold, and heat and cure continuously to form a polyurethane composite material.

[0043] Comparative Example 1: A preparation method of a continuous fiber-reinforced polyurethane composite material: S1: Immerse the UHMWPE fabric in dopamine solution and stir at room temperature for 18 h to obtain dopamine-modified UHMWPE fabric; dissolve 1.4 mmol of zinc acetate dihydrate in ethanol solution, dissolve 1 mmol of sodium hydroxide in ethanol solution and react at 65 °C for 2 h, immerse the dopamine-modified UHMWPE fabric in it for 15 min, anneal at 100 °C, and repeat the immersion and annealing operations 3 times to obtain pretreated UHMWPE fabric; mix 3 g of zinc nitrate hexahydrate and 1.4 g of hexamethylenetetramine evenly and dissolve them in water, immerse the pretreated UHMWPE fabric in it, add ammonia water to adjust the pH to 11.2, react at 85 °C for 1 h, wash and dry to obtain zinc oxide-dopamine-modified UHMWPE fabric;

[0044] The remaining steps are the same as those in Example 1.

[0045] Comparative Example 2: A preparation method of a continuous fiber-reinforced polyurethane composite material: S1: Immerse the UHMWPE fabric in dopamine solution and stir at room temperature for 18 h to obtain dopamine-modified UHMWPE fabric; dissolve 1.4 mmol of zinc acetate dihydrate in ethanol solution, dissolve 1 mmol of sodium hydroxide in ethanol solution and react at 65 °C for 2 h, immerse the dopamine-modified UHMWPE fabric in it for 15 min, anneal at 100 °C, and repeat the immersion and annealing operations 3 times to obtain pretreated UHMWPE fabric; mix 3 g of zinc nitrate hexahydrate and 1.4 g of hexamethylenetetramine evenly and dissolve them in water, immerse the pretreated UHMWPE fabric in it, add 10 mmol of polyethyleneimine, react at 75 °C for 1 h, add ammonia water to adjust the pH to 11.2, react at 85 °C for 1 h, wash and dry to obtain zinc oxide-dopamine-modified UHMWPE fabric;

[0046] The remaining steps are the same as those in Example 1.

[0047] Comparative Example 3: A preparation method of a continuous fiber-reinforced polyurethane composite material: S1: Immerse the UHMWPE fabric in dopamine solution and stir at room temperature for 18 h to obtain dopamine-modified UHMWPE fabric; dissolve 1.4 mmol of zinc acetate dihydrate in ethanol solution, dissolve 1 mmol of sodium hydroxide in ethanol solution and react at 65 °C for 2 h, immerse the dopamine-modified UHMWPE fabric in it for 15 min, anneal at 100 °C, and repeat the immersion and annealing operations 3 times to obtain pretreated UHMWPE fabric; mix 3 g of zinc nitrate hexahydrate and 1.4 g of hexamethylenetetramine evenly and dissolve them in water, immerse the pretreated UHMWPE fabric in it, add 1 mmol of polyethyleneimine, react at 85 °C for 1 h, wash and dry to obtain zinc oxide-dopamine-modified UHMWPE fabric;

[0048] The remaining steps are the same as those in Example 1.

[0049] Test: The polyurethane composite material was prepared into test samples with a size of 16 mm × 16 mm × 7 mm. Among them, the thickness of the composite material prepared from the compound resin stock solution in the 7-mm thickness was 6 mm, and the thickness of the upper and lower two pieces of secondary modified UHMWPE fabric was 0.5 mm.

[0050] Mechanical property test: The tensile property of the material was measured according to GB / T 1447-2005, and the loading speed was 2 mm / min;

[0051] The compression property of the material was measured according to GB / T 1448-2005, and the loading speed was 2 mm / min;

[0052] The bending property of the material was measured according to GB / T 1449-2005, and the loading speed was 2 mm / min.

[0053] Physical property test: The Barcol hardness of the material was measured according to GB / T 3854-2017.

[0054] Table 1 Performance test of polyurethane composite material

[0055] Barcol hardness Tensile strength / MPa Compressive strength / MPa Flexural strength / MPa Example 1 52 1230 880 1211 Example 2 54 1331 829 1195 Example 3 55 1266 830 1236 Comparative example 1 46 1012 678 914 Comparative example 2 41 809 625 799 Comparative example 3 44 936 659 855

[0056] Conclusion: The polyurethane materials prepared in Examples 1-3 have the advantages of high strength and good impact resistance.

[0057] In Comparative Example 1, polyethyleneimine was not added, and in Comparative Example 3, ammonia water was not added, resulting in a decrease in the performance of the prepared polyurethane material.

[0058] In Comparative Example 2, an excessive amount of polyethyleneimine was added, resulting in a decrease in the density and length of the zinc oxide nanorod arrays. With the further increase of polyethyleneimine, the growth of zinc oxide will be completely inhibited.

[0059] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of a continuous fiber reinforced polyurethane composite material, characterized in that: It includes the following steps: S1: Immerse the zinc oxide-dopamine modified UHMWPE fabric in a sodium hypochlorite solution with a concentration of 0.2 - 0.3 mol / L and a pH of 3.5 - 4, stir at 60 - 65 °C for 30 - 45 min, wash, and dry to obtain the chlorinated UHMWPE fabric; Add hydroxyethyl methacrylate, cuprous chloride, copper chloride, and 2,2'-bipyridine into an aqueous methanol solution, stir evenly, immerse the chlorinated UHMWPE fabric therein, and react at 60 - 65 °C in a nitrogen atmosphere for 2 - 3 h, wash, and dry to obtain the secondarily modified UHMWPE fabric; S2: Disperse starch in deionized water, sequentially add sodium carbonate, sodium trimetaphosphate, and sodium hydroxide, react at 50 - 55 °C for 24 - 28 h, adjust the pH to 6.5 - 7.5, wash, filter, and dry to obtain the crosslinking agent; Mix hydroxy silicone oil A and the crosslinking agent evenly, add boric acid, and react at 160 - 165 °C for 2 - 3 h to obtain shear thickening gum A; React hydroxy silicone oil B and boric acid at 160 - 165 °C for 2 - 3 h to obtain shear thickening gum B; S3: Mix polyether polyol, chain extender, catalyst, foam stabilizer, and defoamer evenly to obtain the resin stock solution, add shear thickening gum A and mix evenly to obtain the compounded resin stock solution; Coat shear thickening gum B on the surface of the secondarily modified UHMWPE fabric, place it in an environment of 160 - 165 °C and bake for 30 - 45 min to obtain the composite UHMWPE fabric; Take two pieces of the composite UHMWPE fabric with the side without coated shear thickening gum B facing inwards, place them on the top and bottom surfaces of the mold respectively, continuously and statically mix and inject the compounded resin stock solution and isocyanate into the mold, and heat and cure continuously to form the polyurethane composite material; The zinc oxide-dopamine modified UHMWPE fabric is prepared by the following method: Immerse the UHMWPE fabric in a dopamine solution, stir at room temperature for 18 - 24 h to obtain the dopamine modified UHMWPE fabric; React the zinc acetate dihydrate-ethanol solution and the sodium hydroxide-ethanol solution at 65 - 70 °C for 2 - 3 h, immerse the dopamine modified UHMWPE fabric therein for 15 - 20 min, anneal at 100 °C, and repeat the immersion and annealing operations 1 - 3 times to obtain the pretreated UHMWPE fabric; Mix zinc nitrate hexahydrate and hexamethylenetetramine evenly and dissolve them in water, immerse the pretreated UHMWPE fabric therein, add polyethyleneimine, react at 75 - 80 °C for 1 - 2 h, add ammonia water to adjust the pH, and react at 85 - 95 °C for 1 - 2 h, wash, and dry to obtain the zinc oxide-dopamine modified UHMWPE fabric; The mass ratio of zinc nitrate hexahydrate to hexamethylenetetramine is 0.3:0.14, the addition amount of polyethyleneimine is 1 - 5 mmol, and ammonia water adjusts the pH to 11.2 - 11.

6.

2. The preparation method of a continuous fiber reinforced polyurethane composite material according to claim 1, characterized in that: The dopamine solution is a mixed solution of a tris(hydroxymethyl)aminomethane solution with a concentration of 1.2 - 1.4 g / L and a dopamine hydrochloride solution with a concentration of 2 g / L, and the pH is 8.5; in the zinc acetate dihydrate - ethanol solution, the added amount of zinc acetate dihydrate is 1.4 - 1.6 mmol, and in the sodium hydroxide - ethanol solution, the added amount of sodium hydroxide is 1 - 1.2 mmol.

3. The preparation method of a continuous fiber reinforced polyurethane composite material according to claim 1, characterized in that: In the secondary - modified UHMWPE fabric, the mass ratio of 2 - hydroxyethyl methacrylate : cuprous chloride : copper chloride : 2,2’ - bipyridine is (130 - 150) : (1 - 1.15) : (0.34 - 0.39) : (3.12 - 3.6), and the volume ratio of the methanol aqueous solution is 1:

1.

4. The preparation method of a continuous fiber reinforced polyurethane composite material according to claim 1, characterized in that: In the cross - linker, the mass ratio of starch : sodium carbonate : sodium trimetaphosphate : sodium hydroxide is (100 - 120) : (3 - 3.6) : (3.3 - 4) : (1.1 - 1.3).

5. The preparation method of a continuous fiber reinforced polyurethane composite material according to claim 1, characterized in that: In the shear - thickening gum A, the viscosity of hydroxy silicone oil A is 2000 - 3000 cst, the mass ratio of hydroxy silicone oil A : boric acid is 100 : (0.4 - 0.5), and the mass ratio of hydroxy silicone oil A : cross - linker is (2 - 5) : (5 - 8).

6. The preparation method of a continuous fiber reinforced polyurethane composite material according to claim 1, characterized in that: In the shear - thickening gum B, the viscosity of hydroxy silicone oil B is 100 - 200 cst, and the mass ratio of hydroxy silicone oil B : boric acid is 100 : (1 - 1.2).

7. The preparation method of a continuous fiber reinforced polyurethane composite material according to claim 1, characterized in that, The mass ratio of the resin stock solution : isocyanate is 100 : (92.4 - 96.6); in the compounded resin stock solution, by mass fraction, there are 80 - 100 parts of the resin stock solution, 15 - 20 parts of the shear - thickening gum A. The curing temperature is 130 - 135 °C.

8. The preparation method of a continuous fiber reinforced polyurethane composite material according to claim 1, characterized in that: In the resin stock solution, by mass fraction, there are 80 - 100 parts of polyether polyol, 1 - 5 parts of chain extender, 1 - 2 parts of catalyst, 0.5 - 2 parts of foam stabilizer, and 15 - 25 parts of defoamer.

9. A polyurethane composite material prepared by the preparation method of a continuous fiber - reinforced polyurethane composite material according to any one of claims 1 - 8.