A method for preparing a high-performance integrated polyurethane elastomer auxetic material

Abstract

The present invention belongs to the field of polymer auxetic materials, and specifically relates to a method for preparing a high-performance, integrated polyurethane elastomer auxetic material. Specifically, two molds of identical size, geometric structure, and patterned hollow structures are first prepared using a rigid sheet material. A polyurethane elastomer is then sandwiched between the two molds, and a hydrogen bond modulator is filled into the gaps in the hollow structures. The hydrogen bond network is patterned by infiltration, and the integrated polyurethane elastomer auxetic material is obtained after demolding. The present invention utilizes a strategy for densifying hydrogen bond arrays to prepare thermoplastic polyurethane elastomers with excellent mechanical properties. By patterning and modulating the hydrogen bond network, a polyurethane elastomer auxetic material is obtained, addressing the problems of weak mechanical properties and poor interfacial stability of polyurethane elastomer auxetic materials, and enabling the application of polyurethane elastomer auxetic materials in the field of flexible stretchable materials.

Description

Technical field:

[0001] The present invention belongs to the field of polymer auxetic materials, and in particular relates to a method for preparing a high-performance integrated polyurethane elastomer auxetic material. Background technology:

[0002] Auxetic materials are materials that exhibit negative Poisson's ratios, expanding perpendicularly when subjected to tension and / or contracting when subjected to compression. This auxetic behavior can improve a material's shear modulus, indentation resistance, fracture toughness, and energy absorption capacity, and holds significant potential for application in medical devices, cushioning and protective equipment, smart sensors and filters, aviation, marine, and defense industries. Traditional materials typically achieve negative Poisson's ratios through geometric shapes and deformation-based design, creating auxetic materials and structures from the macroscopic to the molecular level. Examples include concave structures, rotating rigid bodies, chiral / antichiral structures, fiber / node structures, origami structures, and pleated structures. The rotation, expansion, and contraction of these structural frameworks imbue these traditional materials with negative Poisson's ratios.

[0003] Currently, the auxetic geometric structures of polymer auxetic materials often contain hinges and pores, which significantly weaken the material's performance. Stress concentration is also prone to occur near the hinge areas, making the auxetic material susceptible to fatigue and significantly limiting its application. Composite materials with appropriate geometric structures and compositions can effectively overcome this bottleneck. Auxetic structural materials serve as reinforcements, while soft materials serve as the matrix. Thanks to the auxetic effect of the reinforcements, the soft matrix dissipates stress under biaxial or triaxial loading, improving the composite's strength and toughness through the synergistic effect of the soft and hard phases. However, these auxetic composites have weak interfacial bonding between the two phases, making them prone to localized delamination and other phenomena, which affect the material's stability in use.

[0004] Based on this, the present invention increases the hydrogen bonding sites in the polyurethane elastomer, densifies the hydrogen bonding array, thereby improving the mechanical properties of the polyurethane elastomer, and uses a hydrogen bonding regulator to pattern the hydrogen bonding network, giving the polyurethane elastomer tensile properties while solving the defects of the material such as poor mechanical properties and weak interfacial bonding force, thereby realizing the application of polyurethane elastomer tensile materials in the field of flexible stretchable materials. Summary of the invention:

[0005] The purpose of the present invention is to solve the problems of poor mechanical properties and weak interfacial bonding force of polymer auxetic materials and to provide a method for preparing a high-performance integrated polyurethane elastomer auxetic material.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A method for preparing a high-performance integrated polyurethane elastomer auxetic material, the method comprising the following steps:

[0008] (1) Compound A and catalyst B are dissolved in a solvent and reacted with hydroxyl-terminated compound C at 60-80 °C for 0.5-2 h;

[0009] (2) Compound D is added to the reaction system, and chain extender E is added, and the reaction is continued at 60-80°C for 12-24 hours. After the reaction is completed and the solvent is removed, a high-strength and high-toughness polyurethane elastomer is obtained;

[0010] (3) Two molds of the same size, geometric structure and patterned hollow structure are prepared using hard plates, the polyurethane elastomer is sandwiched between the two molds, and the gaps in the hollow structure are filled with a hydrogen bond regulator F, the hydrogen bond network is patterned by infiltration, and the integrated polyurethane elastomer auxetic material is obtained by demolding;

[0011] The compound A is one or more of toluene diisocyanate, methylcyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexane diisocyanate, and lysine diisocyanate;

[0012] The catalyst B is one or more of stannous octoate, dibutyltin dilaurate, zinc naphthenate, and tetraisobutyl titanate;

[0013] The compound C is one or more of polypropylene glycol, polytetramethylene glycol, polyneopentyl adipate, and polyhexyl carbonate diol;

[0014] The compound D is one or more of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, 1,5-naphthalene diisocyanate, dimethylbiphenyl diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, and norbornane diisocyanate;

[0015] The chain extender E is one or more of isophthalic acid hydrazide, 3,3'-dichloro-4,4'-diaminophenylmethane, succinic acid dihydrazide, diethyltoluenediamine, bis-sec-butylaminodiphenylmethane, adipic acid dihydrazide, and sebacic acid dihydrazide;

[0016] The hydrogen bond regulator F is one or more of polyethyleneimine, fatty acid diacid, polyethylene glycol, dioctyl terephthalate, urea, and acetyl tributyl citrate;

[0017] The solvent is one or more of tetrahydrofuran, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide.

[0018] The molar amount of the compound D is 1-3 times that of the compound C, and the molar amount of the chain extender E is 2-4 times that of the compound C.

[0019] Wherein, the molar ratio of compound A to compound C is 2:1~3:1.

[0020] Wherein, the hard plate material is one or more of polypropylene, polytetrafluoroethylene, and polymethyl methacrylate.

[0021] The geometric structure is one or more of a concave hexagon, a double-arrow concave, a star-shaped concave, a center-rotated square, a center-rotated diamond, and a sinusoidal band link structure.

[0022] Beneficial effects:

[0023] First, the present invention utilizes hydrogen bond array densification strategy to strengthen the hard phase structure of polyurethane elastomer, and prepares a polyurethane elastomer with high strength (tensile strength above 60 MPa), high toughness (toughness 300MJ / m 3 The polyurethane elastomer material (above) has significant mechanical performance advantages.

[0024] Secondly, this invention creates an integrated auxetic material by patterning the hydrogen bond network, addressing the poor mechanical properties and weak interfacial forces inherent in polyurethane elastomer auxetic materials. Furthermore, the material exhibits excellent thermal stability and transparency, promising broad application prospects in the field of flexible, stretchable materials. Description of the drawings:

[0025] Figure 1 The transmission spectrum and physical photograph of the polyurethane elastomer sample of Example 1 of the present invention are shown.

[0026] Figure 2 This is the infrared spectrum of the polyurethane elastomer sample of Example 1 of the present invention.

[0027] Figure 3 This is an atomic force microscope image of the polyurethane elastomer sample of Example 1 of the present invention. Specific implementation method:

[0028] In view of the shortcomings of the existing technology, the present invention provides a method for preparing an integrated polyurethane elastomer auxetic material by patterning the hydrogen bond network in the polyurethane elastomer, thereby solving the problems of poor mechanical properties and weak interfacial forces of the polyurethane elastomer auxetic material.

[0029] In order to further understand the embodiments of the present application or the technical solutions in the prior art, the present invention is described in detail below in conjunction with specific embodiments and the accompanying drawings. However, the embodiments do not limit the present invention. All variations that can be imagined or derived are considered to be within the scope of protection of the present invention.

[0030] Example 1

[0031] In this example, polypropylene glycol, isophorone diisocyanate, diphenylmethane diisocyanate, and diethyltoluenediamine were reacted in a molar ratio of 1:2:1:2 to obtain a polyurethane elastomer with excellent mechanical properties. A mold having a concave hexagonal structure was then used to pattern the hydrogen bond network of the elastomer using a hydrogen bond modulator (a fatty acid diacid solution) to prepare an integrated polyurethane elastomer auxetic material. The method is as follows:

[0032] (1) Dissolve 2.22 g of isophorone diisocyanate and 0.02 g of tetraisobutyl titanate in tetrahydrofuran and react with 10 g of polypropylene glycol-2000 at 70 °C for 2 h.

[0033] (2) 1.25 g of diphenylmethane diisocyanate was added to the reaction system, and 1.78 g of diethyltoluenediamine was added, and the reaction was continued at 70 °C for 24 h. After removing the solvent, a high-strength and high-toughness polyurethane elastomer was obtained.

[0034] (3) A concave hexagonal structure was engraved on a polypropylene sheet using a laser to obtain a mold with a patterned structure. A polyurethane elastomer was sandwiched between two molds, and a methanol solution of fatty acid diacids was filled into the structural gaps. The hydrogen bond network was patterned by infiltration to prepare an integrated polyurethane elastomer auxetic material.

[0035] Example 2

[0036] In this example, polypropylene glycol, isophorone diisocyanate, diphenylmethane diisocyanate, and diethyltoluenediamine were reacted in a molar ratio of 1:2:2:3 to obtain a polyurethane elastomer with excellent mechanical properties. A hydrogen bond modulator (a fatty acid diacid solution) was then used to pattern the elastomer's hydrogen bond network using a mold having a concave hexagonal structure to prepare an integrated polyurethane elastomer auxetic material. The method is as follows:

[0037] (1) Dissolve 2.22 g of isophorone diisocyanate and 0.02 g of tetraisobutyl titanate in tetrahydrofuran and react with 10 g of polypropylene glycol-2000 at 70 °C for 2 h.

[0038] (2) 2.50 g of diphenylmethane diisocyanate was added to the reaction system, and 2.67 g of diethyltoluenediamine was added, and the reaction was continued at 70 °C for 24 h. After removing the solvent, a high-strength and high-toughness polyurethane elastomer was obtained.

[0039] (3) A concave hexagonal structure was engraved on a polypropylene sheet using a laser to obtain a mold with a patterned structure. A polyurethane elastomer was sandwiched between two molds, and a methanol solution of fatty acid diacids was filled into the structural gaps. The hydrogen bond network was patterned by infiltration to prepare an integrated polyurethane elastomer auxetic material.

[0040] Example 3

[0041] In this example, polypropylene glycol, lysine diisocyanate, diphenylmethane diisocyanate, and diethyltoluenediamine were reacted in a molar ratio of 1:2:2:3 to obtain a polyurethane elastomer with excellent mechanical properties. A hydrogen bond modulator (a fatty acid diacid solution) was then used to pattern the elastomer's hydrogen bond network using a mold having a concave hexagonal structure to prepare an integrated polyurethane elastomer auxetic material. The method is as follows:

[0042] (1) Dissolve 2.26 g of lysine diisocyanate and 0.02 g of tetraisobutyl titanate in tetrahydrofuran and react with 10 g of polypropylene glycol-2000 at 70 °C for 2 h.

[0043] (2) 2.50 g of diphenylmethane diisocyanate was added to the reaction system, and 2.67 g of diethyltoluenediamine was added, and the reaction was continued at 70 °C for 24 h. After removing the solvent, a high-strength and high-toughness polyurethane elastomer was obtained.

[0044] (3) A concave hexagonal structure was engraved on a polypropylene sheet using a laser to obtain a mold with a patterned structure. A polyurethane elastomer was sandwiched between two molds, and a methanol solution of fatty acid diacids was filled into the structural gaps. The hydrogen bond network was patterned by infiltration to prepare an integrated polyurethane elastomer auxetic material.

[0045] Example 4

[0046] In this example, polypropylene glycol, lysine diisocyanate, diphenylmethane diisocyanate, and isophthalic acid hydrazide were reacted in a molar ratio of 1:2:2:3 to obtain a polyurethane elastomer with excellent mechanical properties. A hydrogen bond modulator (a fatty acid diacid solution) was then used to pattern the elastomer's hydrogen bond network using a mold having a concave hexagonal structure to prepare an integrated polyurethane elastomer auxetic material. The method is as follows:

[0047] (1) Dissolve 2.26 g of lysine diisocyanate and 0.02 g of tetraisobutyl titanate in tetrahydrofuran and react with 10 g of polypropylene glycol-2000 at 70 °C for 2 h.

[0048] (2) 2.50 g of diphenylmethane diisocyanate was added to the reaction system, and 2.91 g of isophthalic acid hydrazide was added, and the reaction was continued at 70 °C for 24 h. After removing the solvent, a high-strength and high-toughness polyurethane elastomer was obtained.

[0049] (3) A concave hexagonal structure is engraved on a polypropylene sheet using a laser to obtain a mold with a patterned structure. A polyurethane elastomer is sandwiched between two molds, and a methanol solution of a fatty acid diacid is filled into the structural gaps. The hydrogen bond network is patterned by infiltration to prepare an integrated polyurethane elastomer auxetic material.

[0050] Example 5

[0051] In this example, polypropylene glycol, lysine diisocyanate, diphenylmethane diisocyanate, and isophthalic acid hydrazide were reacted in a molar ratio of 1:2:2:3 to obtain a polyurethane elastomer with excellent mechanical properties. A mold having a sinusoidal band link structure was then used to pattern the hydrogen bond network of the elastomer using a hydrogen bond modulator (a fatty acid diacid solution) to prepare an integrated polyurethane elastomer auxetic material. The method is as follows:

[0052] (1) Dissolve 2.26 g of lysine diisocyanate and 0.02 g of tetraisobutyl titanate in tetrahydrofuran and react with 10 g of polypropylene glycol-2000 at 70 °C for 2 h.

[0053] (2) 2.50 g of diphenylmethane diisocyanate was added to the reaction system, and 2.91 g of isophthalic acid hydrazide was added, and the reaction was continued at 70 °C for 24 h. After removing the solvent, a high-strength and high-toughness polyurethane elastomer was obtained.

[0054] (3) A sinusoidal band link structure was laser-engraved on a polypropylene sheet to obtain a mold with a patterned structure. A polyurethane elastomer was sandwiched between two molds, and a methanol solution of fatty acid diacids was filled into the structural gaps. The hydrogen bond network was patterned by infiltration to prepare an integrated polyurethane elastomer auxetic material.

[0055] Example 6

[0056] In this example, polypropylene glycol, lysine diisocyanate, diphenylmethane diisocyanate, and isophthalic acid hydrazide were reacted in a molar ratio of 1:2:2:3 to obtain a polyurethane elastomer with excellent mechanical properties. A mold having a sinusoidal band link structure was then used to pattern the hydrogen bond network of the elastomer using a hydrogen bond modulator (urea solution) to prepare an integrated polyurethane elastomer auxetic material. The method is as follows:

[0057] (1) Dissolve 2.26 g of lysine diisocyanate and 0.02 g of tetraisobutyl titanate in tetrahydrofuran and react with 10 g of polypropylene glycol-2000 at 70 °C for 2 h.

[0058] (2) 2.50 g of diphenylmethane diisocyanate was added to the reaction system, and 2.91 g of isophthalic acid hydrazide was added, and the reaction was continued at 70 °C for 24 h. After removing the solvent, a high-strength and high-toughness polyurethane elastomer was obtained.

[0059] (3) A sinusoidal band link structure is laser-engraved on a polypropylene sheet to obtain a mold with a patterned structure. A polyurethane elastomer is sandwiched between two molds, and a methanol solution of urea is filled into the structural gaps. The hydrogen bond network is patterned by infiltration to prepare an integrated polyurethane elastomer auxetic material.

[0060] Example 7

[0061] In this example, four compounds, polytetrahydrofuran diol, isophorone diisocyanate, toluene diisocyanate, and 3,3'-dichloro-4,4'-diaminophenylmethanehydrazine, were reacted in a molar ratio of 1:2:3:4 to obtain a polyurethane elastomer with excellent mechanical properties. Furthermore, a hydrogen bond modulator (polyethyleneimine solution) was used to pattern the elastomer's hydrogen bond network using a mold having a concave hexagonal structure to prepare an integrated polyurethane elastomer auxetic material. The method is as follows:

[0062] (1) Dissolve 1.74 g of isophorone diisocyanate and 0.02 g of stannous octoate in N-methylpyrrolidone and react with 10 g of polytetramethylene glycol at 60 °C for 0.5 h.

[0063] (2) 3.75 g, 250.25 g / mol, 15 mmol toluene diisocyanate was added to the reaction system, along with 3.88 g 3,3'-dichloro-4,4'-diaminophenylmethane. The reaction was continued at 60 °C for 12 h. After removing the solvent, a high-strength and high-toughness polyurethane elastomer was obtained.

[0064] (3) Laser engraving of a double-arrow concave pattern on a polytetrafluoroethylene sheet creates a mold with a patterned structure. A polyurethane elastomer is sandwiched between the two molds, and a methanol solution of polyethyleneimine is filled into the structural gaps. The hydrogen bond network is patterned by infiltration, resulting in the preparation of an integrated polyurethane elastomer auxetic material.

[0065] Example 8

[0066] In this example, four compounds, poly(neopentyl adipate), methylcyclohexane diisocyanate, isophorone diisocyanate, and succinic dihydrazide, were reacted in a molar ratio of 1:2:3:4 to obtain a polyurethane elastomer with excellent mechanical properties. Furthermore, a hydrogen bond modulator (polyethylene glycol solution) was used to pattern the elastomer's hydrogen bond network using a mold having a concave hexagonal structure to prepare an integrated polyurethane elastomer auxetic material. The method is as follows:

[0067] (1) Dissolve 1.94 g of methylcyclohexane diisocyanate and 0.02 g of dibutyltin dilaurate in N, N-dimethylformamide and react with 10 g of poly (neopentyl adipate) at 80 °C for 1 h.

[0068] (2) 3.75 g of isophorone diisocyanate was added to the reaction system, and 3.88 g of succinic acid dihydrazide was added, and the reaction was continued at 80 °C for 18 h. After removing the solvent, a high-strength and high-toughness polyurethane elastomer was obtained.

[0069] (3) A star-shaped concave pattern was engraved on a polypropylene sheet using a laser to obtain a mold with a patterned structure. A polyurethane elastomer was sandwiched between two molds, and a methanol solution of polyethylene glycol was filled into the structural gaps. The hydrogen bond network was patterned by infiltration to prepare an integrated polyurethane elastomer auxetic material.

[0070] Example 9

[0071] In this example, poly(neopentyl adipate), 1,4-cyclohexane diisocyanate, dicyclohexylmethane diisocyanate, and diethyltoluenediamine were reacted in a molar ratio of 1:3:1:3 to obtain a polyurethane elastomer with excellent mechanical properties. Furthermore, a hydrogen bond modulator (a fatty acid diacid solution) was used to pattern the elastomer's hydrogen bond network using a mold having a concave hexagonal structure to prepare an integrated polyurethane elastomer auxetic material. The method is as follows:

[0072] (1) Dissolve 2.49 g of 1,4-cyclohexane diisocyanate and 0.02 g of stannous octoate in N,N-dimethylformamide and react with 10 g of poly(neopentyl adipate) at 80 °C for 1 h.

[0073] (2) 1.25 g of dicyclohexylmethane diisocyanate was added to the reaction system, and 2.91 g of diethyltoluenediamine was added, and the reaction was continued at 80 °C for 18 h. After removing the solvent, a high-strength and high-toughness polyurethane elastomer was obtained.

[0074] (3) A laser was used to engrave a central rotating square on a polypropylene sheet to obtain a mold with a patterned structure. A polyurethane elastomer was sandwiched between two molds, and a methanol solution of fatty acid diacids was filled into the structural gaps. The hydrogen bond network was patterned by infiltration to prepare an integrated polyurethane elastomer auxetic material.

[0075] Example 10

[0076] In this example, four compounds, poly(neopentyl adipate), isophorone diisocyanate, 1,5-naphthalene diisocyanate, and bis-sec-butylaminodiphenylmethane, were reacted in a molar ratio of 1:3:1:3 to obtain a polyurethane elastomer with excellent mechanical properties. Furthermore, a hydrogen bond modulator (a fatty acid diacid solution) was used to pattern the elastomer's hydrogen bond network using a mold having a concave hexagonal structure to prepare an integrated polyurethane elastomer auxetic material. The method is as follows:

[0077] (1) 3.33 g of isophorone diisocyanate and 0.02 g of stannous octoate were dissolved in N, N-dimethylacetamide and reacted with 10 g of poly (neopentyl adipate) at 80 °C for 1 h.

[0078] (2) 1.25 g of 1,5-naphthalene diisocyanate was added to the reaction system, and 2.91 g of bis-sec-butylaminodiphenylmethane was added, and the reaction was continued at 80 °C for 18 h. After removing the solvent, a high-strength and high-toughness polyurethane elastomer was obtained.

[0079] (3) A laser was used to engrave a central rotating diamond on a polypropylene sheet to obtain a mold with a patterned structure. A polyurethane elastomer was sandwiched between two molds, and a methanol solution of fatty acid diacids was filled into the structural gaps. The hydrogen bond network was patterned by infiltration to prepare an integrated polyurethane elastomer auxetic material.

[0080] Example 11

[0081] In this example, poly(neopentyl adipate), dicyclohexylmethane diisocyanate, dimethylbiphenyl diisocyanate, and adipic acid dihydrazide were reacted in a molar ratio of 1:3:1:3 to obtain a polyurethane elastomer with excellent mechanical properties. Furthermore, a hydrogen bond modulator (dioctyl terephthalate solution) was used to pattern the elastomer's hydrogen bond network using a mold having a concave hexagonal structure to prepare an integrated polyurethane elastomer auxetic material. The method is as follows:

[0082] (1) 3.94 g of dicyclohexylmethane diisocyanate and 0.02 g of dibutyltin dilaurate were dissolved in dimethyl sulfoxide and reacted with 10 g of poly(neopentyl adipate) at 80 °C for 1 h.

[0083] (2) 1.25 g of dimethyldiphenyl diisocyanate was added to the reaction system, and 2.91 g of adipic acid dihydrazide was added, and the reaction was continued at 80 °C for 18 h. After removing the solvent, a high-strength and high-toughness polyurethane elastomer was obtained.

[0084] (3) A sinusoidal band link structure is engraved on a polytetrafluoroethylene sheet using a laser to obtain a mold with a patterned structure. A polyurethane elastomer is sandwiched between two molds, and a methanol solution of dioctyl terephthalate is filled into the structural gaps. The hydrogen bond network is patterned by infiltration to prepare an integrated polyurethane elastomer auxetic material.

[0085] Example 12

[0086] In this example, polytetrahydrofuran diol, hexamethylene diisocyanate, xylylenediisocyanate, and sebacic acid dihydrazide were reacted in a molar ratio of 1:3:2:4 to obtain a polyurethane elastomer with excellent mechanical properties. A hydrogen bond modulator (a fatty acid diacid ester solution) was then used to pattern the elastomer's hydrogen bond network using a mold having a concave hexagonal structure to prepare an integrated polyurethane elastomer auxetic material. The method is as follows:

[0087] (1) Dissolve 2.52 g of hexamethylene diisocyanate and 0.02 g of zinc cyclohexane in dimethyl sulfoxide and react with 10 g of polytetrahydrofuran diol at 80 °C for 1 h.

[0088] (2) 2.50 g of benzyl diisocyanate was added to the reaction system, and 3.88 g of sebacic acid dihydrazide was added, and the reaction was continued at 80 °C for 18 h. After removing the solvent, a high-strength and high-toughness polyurethane elastomer was obtained.

[0089] (3) A sinusoidal band link structure was laser-engraved on a polypropylene sheet to obtain a mold with a patterned structure. A polyurethane elastomer was sandwiched between two molds, and a methanol solution of fatty acid diacids was filled into the structural gaps. The hydrogen bond network was patterned by infiltration to prepare an integrated polyurethane elastomer auxetic material.

[0090] Example 13

[0091] In this example, four compounds, polyhexyl carbonate diol, 2,2,4-trimethylhexamethylene diisocyanate, tetramethylxylylene diisocyanate, and isophthalic acid hydrazide, were reacted in a molar ratio of 1:3:2:4 to obtain a polyurethane elastomer with excellent mechanical properties. Furthermore, a hydrogen bond modulator (a fatty acid diacid solution) was used to pattern the elastomer's hydrogen bond network using a mold having a concave hexagonal structure to prepare an integrated polyurethane elastomer auxetic material. The method is as follows:

[0092] (1) 2.52 g of 2, 2, 4-trimethylhexane diisocyanate and 0.02 g of zinc cyclohexaneate were dissolved in N-methylpyrrolidone and reacted with 10.09 g of polyhexyl carbonate diol at 80 °C for 1 h.

[0093] (2) 2.50 g of tetramethylxylene diisocyanate was added to the reaction system, and 3.88 g of isophthalic acid hydrazide was added, and the reaction was continued at 80 °C for 18 h. After removing the solvent, a high-strength and high-toughness polyurethane elastomer was obtained.

[0094] (3) A sinusoidal band link structure was laser-engraved on a polymethyl methacrylate sheet to obtain a mold with a patterned structure. A polyurethane elastomer was sandwiched between two molds, and a methanol solution of fatty acid diacids was filled into the structural gaps. The hydrogen bond network was patterned by infiltration to prepare an integrated polyurethane elastomer auxetic material.

[0095] Example 14

[0096] In this example, polyhexyl carbonate diol, lysine diisocyanate, norbornane diisocyanate, and isophthalic acid hydrazide were reacted in a molar ratio of 1:3:2:4 to obtain a polyurethane elastomer with excellent mechanical properties. A mold having a concave hexagonal structure was then used to pattern the hydrogen bond network of the elastomer using a hydrogen bond modulator (acetyl tributyl citrate solution) to prepare an integrated polyurethane elastomer auxetic material. The method is as follows:

[0097] (1) 3.39 g of lysine diisocyanate and 0.02 g of dibutyltin dilaurate were dissolved in tetrahydrofuran and reacted with 10.09 g of polyhexyl carbonate diol at 70 °C for 1 h.

[0098] (2) 2.50 g of norbornane diisocyanate was added to the reaction system, along with 3.88 g of isophthalic acid hydrazide, and the reaction was continued at 80 °C for 18 h. After removing the solvent, a high-strength and high-toughness polyurethane elastomer was obtained.

[0099] (3) Laser engraving of concave hexagonal structures on polymethyl methacrylate sheets yields a mold with a patterned structure. A polyurethane elastomer is sandwiched between two molds, and a methanol solution of acetyl tributyl citrate is filled into the structural voids. The hydrogen bond network is patterned by infiltration, resulting in the preparation of an integrated polyurethane elastomer auxetic material.

[0100] Comparative Example 1

[0101] To illustrate the importance of hydrogen bond modulators, in this comparative example, polypropylene glycol, lysine diisocyanate, diphenylmethane diisocyanate, and isophthalic acid hydrazide were reacted in a molar ratio of 1:2:2:3 to obtain a polyurethane elastomer with excellent mechanical properties. Methanol was then filled into the gaps of a sinusoidal band link structure mold, and the polyurethane elastomer material of the comparative example was obtained through infiltration drying. The method was as follows:

[0102] (1) Dissolve 2.26 g of lysine diisocyanate and 0.02 g of tetraisobutyl titanate in tetrahydrofuran and react with 10 g of polypropylene glycol-2000 at 70 °C for 2 h.

[0103] (2) 2.50 g of diphenylmethane diisocyanate was added to the reaction system, and 2.91 g of isophthalic acid hydrazide was added, and the reaction was continued at 70 °C for 24 h. After removing the solvent, a high-strength and high-toughness polyurethane elastomer was obtained.

[0104] (3) A sinusoidal band link structure was engraved on a polypropylene sheet using a laser to obtain a mold with a patterned structure. A polyurethane elastomer was sandwiched between two molds, and methanol was filled into the gaps in the structure. After infiltration drying, a polyurethane elastomer material of the comparative example was obtained.

[0105] Tensile properties and Poisson's ratio of polyurethane elastomer auxetic materials

[0106] The polyurethane elastomer materials of Examples 1-6 and Comparative Example 1 were subjected to uniaxial tensile testing at room temperature using an ETM504C universal testing machine at a tensile rate of 50 mm / min. The transverse and longitudinal strains of the materials were recorded during the tensile process, and the Poisson's ratio of the materials at different tensile strains was calculated. The results are shown in Table 1.

[0107] Table 1 Performance indicators of Examples 1 to 14 and Comparative Examples.

[0108]

[0109] As shown in Table 1, the polyurethane elastomer auxetic materials of Examples 1-6 all exhibit excellent mechanical properties. Modifying the components and proportions allows for the manipulation of these properties, and patterning the hydrogen-bonding network does not significantly affect the mechanical properties. Furthermore, compared to the positive Poisson's ratio of Comparative Example 1, Examples 1-6 exhibit negative Poisson's ratios within the tensile strain range of 0-17%, and this negative Poisson's ratio can be manipulated through the auxetic geometry and hydrogen-bonding modifiers.

[0110] In summary, increasing hydrogen bonding sites in polyurethane elastomers can improve their mechanical properties, imparting them with excellent strength and toughness. The patterning of the hydrogen bonding network within the polyurethane elastomer by a hydrogen bonding modulator imparts auxetic properties to the material while maintaining its excellent mechanical properties. This integrated preparation method addresses shortcomings such as poor mechanical properties and weak interfacial bonding forces, enabling the application of polyurethane elastomer auxetic materials in the field of flexible, stretchable materials.

Claims

1. A method for preparing a high-performance integrated polyurethane elastomer auxetic material, characterized in that: The preparation method comprises the following steps: (1) Dissolve compound A and catalyst B in a solvent and react with compound C at 60-80°C for 0.5-2h; (2) Compound D is added to the reaction system, and chain extender E is added, and the reaction is continued at 60-80°C for 12-24 hours. After the reaction is completed, the solvent is removed to obtain a high-strength and high-toughness polyurethane elastomer; (3) Two molds of the same size, geometric structure and patterned hollow structure are prepared using hard plates, the polyurethane elastomer is sandwiched between the two molds, and the gaps in the hollow structure are filled with a hydrogen bond regulator F, the hydrogen bond network is patterned by infiltration, and the integrated polyurethane elastomer auxetic material is obtained by demolding; The compound A is one or more of toluene diisocyanate, methylcyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexane diisocyanate, and lysine diisocyanate; The catalyst B is one or more of stannous octoate, dibutyltin dilaurate, zinc naphthenate, and tetraisobutyl titanate; The compound C is one or more of polypropylene glycol, polytetramethylene glycol, polyneopentyl adipate, and polyhexyl carbonate diol; The compound D is one or more of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, 1,5-naphthalene diisocyanate, dimethylbiphenyl diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, and norbornane diisocyanate; The chain extender E is one or more of isophthalic acid hydrazide, 3,3'-dichloro-4,4'-diaminophenylmethane, succinic acid dihydrazide, diethyltoluenediamine, bis-sec-butylaminodiphenylmethane, adipic acid dihydrazide, and sebacic acid dihydrazide; The hydrogen bond regulator F is one or more of polyethyleneimine, fatty acid diacid, polyethylene glycol, dioctyl terephthalate, urea, and acetyl tributyl citrate; The solvent is one or more of tetrahydrofuran, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide.

2. The method for preparing a high-performance integrated polyurethane elastomer auxetic material according to claim 1, characterized in that: The molar amount of the compound D is 1-3 times that of the compound C, and the molar amount of the chain extender E is 2-4 times that of the compound C.

3. The method for preparing a high-performance integrated polyurethane elastomer auxetic material according to claim 1, characterized in that: The molar ratio of compound A to compound C is 2:1 to 3:

1.

4. The method for preparing a high-performance integrated polyurethane elastomer auxetic material according to claim 1, characterized in that: The hard plate material is one or more of polypropylene, polytetrafluoroethylene, and polymethyl methacrylate.

5. The method for preparing a high-performance integrated polyurethane elastomer auxetic material according to claim 1, characterized in that: The geometric structure is one or more of an inward-concave hexagon, a double-arrow inward-concave, a star-shaped inward-concave, a center-rotated square, a center-rotated diamond, and a sinusoidal belt link structure.

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