A colorless and transparent poly(urethane-urea) elastomer based on mismatch supramolecular action and its preparation method and application

Abstract

The present invention provides a colorless and transparent poly (urethane-urea) elastomer based on mismatch supramolecular action and its preparation method and application. The preparation method of the present invention includes the steps of: in a solvent, under the action of a catalyst, diisocyanate and oligomer polyol are reacted to form a prepolymer; an organic solution of an aliphatic mixed chain extender is mixed with the prepolymer, reacted, and then degassed and dried to obtain a colorless and transparent poly (urethane-urea) elastomer based on the mismatch supramolecular action; the aliphatic mixed chain extender is a combination of adipic acid dihydrazide (ADH) and 1,4-butylene diamine (BDA). The preparation method of the present invention is simple, low in cost, and can be prepared on a large scale; the thermoplastic poly (urethane-urea) obtained by the present invention can stably maintain a colorless and transparent state under ultraviolet aging conditions, has excellent anti-aging performance, and has high strength and high toughness mechanical properties, and has high practical applicability.

Description

Technical Field

[0001] The invention relates to the technical field of high-performance polymer material synthesis, and in particular to a colorless and transparent poly(urethane-urea) elastomer based on mismatch supramolecular action, and a preparation method and application thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] Elastomers are a class of polymer materials that are widely used in industries, lubricants, molds, tires, vehicles, and prosthetics due to their unique ability to return to their original shape after deformation. With the continuous advancement of technology, the elastomer market has shown strong growth momentum.

[0004] The wide application and market prospects of elastomers stem from their unique combination of excellent mechanical properties, recyclability and durability. In order to further improve the performance of elastomers, molecular design methods provide an effective way to significantly enhance the strength of the material and expand its supramolecular interactions by introducing rigid aromatic structures into the polymer matrix. However, aromatic structures also bring significant challenges, especially the problem of material discoloration and decreased transparency under ultraviolet irradiation. For example, Chinese patent document CN115716901A discloses a method and application of using rigid and flexible supramolecular fragments to synergistically toughen thermoplastic poly (urethane-urea). The invention adds two mixed chain extenders that can form rigid and flexible supramolecular effects in the post-formation stage of the prepolymer in the synthesis process of thermoplastic poly (urethane-urea) materials, hybridizes the rigid and flexible supramolecular effects in the polymer chain, so that the material can effectively dissipate the energy applied by the external force when subjected to external stress, thereby improving the toughness of the material. However, due to the introduction of aromatic structures, there are problems that the material itself has color and the material is easy to discolor and decrease in transparency under ultraviolet irradiation. Chinese patent document CN115010896A discloses a method for preparing a thermoplastic elastomer with excellent rebound performance and high strength, comprising the following steps: A) placing at least two soft segment monomers in a solvent and then adding a hard segment monomer, reacting under the action of a catalyst to obtain an initial reactant; B) reacting a chain extender with the initial reactant to obtain a thermoplastic elastomer; the thermoplastic elastomer provided by the invention is endowed with high strength and high modulus by multiple hydrogen bonds in the hard segment monomer, and is endowed with excellent toughness and high rebound properties by the thermodynamic incompatibility of the soft segment monomer; however, the elongation at break of the invention is too low, and it still involves the use of materials containing benzene rings.

[0005] Therefore, how to solve the problem of easy discoloration and decreased transparency of the material under ultraviolet irradiation while maintaining the high mechanical properties of the elastomer has become an important topic in the research of elastomer materials. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides a colorless and transparent poly(urethane-urea) elastomer based on mismatch supramolecular effects, and a preparation method and application thereof. The present invention uses thermoplastic poly(urethane-urea) commonly used in industry as a model system, selects an aliphatic molecular structure to ensure its stable colorless and transparent properties, and introduces mismatch supramolecular interactions therein to significantly improve its mechanical toughness. The preparation method of the present invention is simple, low-cost, and can be prepared on a large scale; the thermoplastic poly(urethane-urea) obtained by the present invention can stably maintain a colorless and transparent state under ultraviolet aging conditions, has excellent anti-aging properties, and at the same time has high-strength and high-toughness mechanical properties, and has high practical applicability.

[0007] The present invention is achieved through the following technical solutions:

[0008] In a first aspect, the present invention provides a method for preparing a colorless and transparent poly(urethane-urea) elastomer based on mismatch supramolecular action, comprising the steps of:

[0009] (1) In a solvent and under the action of a catalyst, diisocyanate and oligomer polyol react to form a prepolymer;

[0010] (2) mixing an organic solution of an aliphatic mixed chain extender with a prepolymer, reacting, degassing, and drying to obtain a colorless and transparent poly(urethane-urea) elastomer based on mismatch supramolecular action;

[0011] The aliphatic mixed chain extender is a combination of adipic acid dihydrazide (ADH) and 1,4-butanediamine (BDA).

[0012] Preferably, in step (1), the solvent is one or a combination of two or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide or N-methylpyrrolidone; and the mass ratio of diisocyanate to solvent is 1:5-20.

[0013] Preferably, in step (1), the catalyst is one or a combination of two or more of dibutyltin dilaurate (DBTDL), stannous octoate or triethylenediamine; and the molar ratio of the catalyst to the diisocyanate is 0.01-0.05:1, preferably 0.025:1.

[0014] Preferably according to the present invention, in step (1), the diisocyanate is 4,4'-dicyclohexylmethane diisocyanate (HMDI) or isophorone diisocyanate (IPDI).

[0015] Preferably according to the present invention, in step (1), the oligomer polyol is one or a combination of two or more of polytetrahydrofuran, polydimethylsiloxane or polycaprolactone.

[0016] Preferably according to the present invention, in step (1), the molar ratio of diisocyanate to oligomer polyol is 1:0.2-1, preferably 1:0.5.

[0017] Preferably, according to the present invention, in step (1), the reaction temperature of the diisocyanate and the oligomer polyol is 60-100° C., the reaction time is 1-3 h, and the reaction is carried out under stirring conditions.

[0018] Preferably according to the present invention, in step (2), in the aliphatic mixed chain extender, the molar ratio of adipic acid dihydrazide (ADH) to 1,4-butanediamine (BDA) is 0.5-2:0.5-2, preferably 1:1.

[0019] Preferably, according to the present invention, in step (2), the mass concentration of the organic solution of the aliphatic mixed chain extender is 1-5%; the solvent used for the organic solution of the aliphatic mixed chain extender is one or a combination of two or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide or N-methylpyrrolidone.

[0020] Preferably according to the present invention, in step (2), the molar amount of the aliphatic mixed chain extender is 40-60% of the molar amount of the diisocyanate, preferably 50%.

[0021] Preferably according to the present invention, in step (2), the reaction temperature is room temperature, the reaction time is 2-7 hours, and the reaction is carried out under stirring conditions.

[0022] Preferably, in step (2), the degassing method is vacuum degassing; the drying conditions are: drying at 70-90°C for 10-14h, and then vacuum drying at 90-110°C for 6-10h.

[0023] In a second aspect, the present invention provides a colorless and transparent poly(urethane-urea) elastomer based on mismatch supramolecular action, which is prepared by the above method.

[0024] The third aspect of the present invention provides an application of a colorless and transparent poly(urethane-urea) elastomer based on mismatch supramolecular action in the field of UV-resistant, high mechanical strength, damage-resistant, and recyclable transparent materials.

[0025] The technical features and beneficial effects of the present invention are as follows:

[0026] 1) The method of the present invention is simple and easy to implement, the raw materials are readily available, the cost is low, the requirements for reaction conditions and equipment used are not high, and large-scale preparation in a 20L reactor can be achieved.

[0027] 2) The present invention adds a new aliphatic mixed chain extender based on the original production process of thermoplastic poly(urethane-urea), solves the problem of material discoloration and decreased transparency under ultraviolet irradiation caused by the introduction of aromatic structure, realizes the colorless, transparent and anti-aging of thermoplastic poly(urethane-urea), can stably maintain the colorless and transparent state under ultraviolet aging conditions, and has excellent anti-aging performance. At the same time, the enhancement and toughening of colorless and transparent poly(urethane-urea) is achieved. The present invention uses a mixed chain extender with mismatched hydrazine and amino groups, which can form mismatched supramolecular effects, i.e. mismatched supramolecular effects, in the molecular structure of the elastomer. The stronger binding force between the hydrazine and amino groups and more hydrogen bonds make it stand out in different mismatched combinations and show the best mechanical properties. The colorless, transparent and anti-aging is because the elastomer structure of the present invention does not contain a benzene ring structure, which is not easy to absorb ultraviolet light and produce a color-changing group. The addition of aromatic structure will increase the ability of the material to absorb ultraviolet (UV), which is due to the interaction between ultraviolet photons and π electron clouds, which promotes the transition of electrons to higher energy levels. This interaction not only changes the color of the material, turning it yellow or brown after long-term use, but also raises concerns about the safety and transparency of the material due to changes in chemical composition and microstructure caused by UV exposure. Therefore, benzene-free elastomers can greatly reduce people's concerns about this.

[0028] 3) Only a specific type of chain extender can achieve the excellent effect of the present invention. If the type of chain extender is not suitable, the ratio of the two chain extenders is not suitable, or the amount of the chain extender is not suitable, the performance of the obtained elastomer will be affected.

[0029] 4) The strategy of improving the mechanical properties of colorless and transparent poly(urethane-urea) elastomers by mismatched supramolecular action provided by the present invention is not limited to thermoplastic poly(urethane-urea) systems, but also has potential application value in toughening other colorless and transparent polymer materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a comparison of the mechanical properties and surface morphology after long-term UV irradiation of benzene ring-containing elastomers and benzene ring-free elastomers reported in the current literature.

[0031] Figure 2 It is a bar graph of toughness data of three elastomers containing mismatch of hydrazine group and amino group (Example 1), mismatch of hydrazine group and hydroxyl group (Comparative Example 4), and mismatch of amino group and hydroxyl group (Comparative Example 5).

[0032] Figure 3 It is a bar graph of toughness data of five elastomers: Example 1, Comparative Example 1, Comparative Example 2, Example 2, and Example 3.

[0033] Figure 4The hydrazine and amino mismatched benzene ring-free elastomer SPU-HA prepared in Example 1 is similar to the toughness>300MJ m reported in the current literature. -3 Comparison of mechanical properties of benzene ring-free elastomers.

[0034] Figure 5 It is a bar graph showing the transparency changes of the SPU-DA containing benzene rings prepared in Comparative Example 3 and the SPU-HA without benzene rings prepared in Example 1 after aging for different days. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples without specifying specific conditions are usually carried out under conventional conditions or under conditions recommended by the manufacturer.

[0036] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present disclosure.

[0037] The present invention will be further described in detail below in conjunction with specific embodiments. It should be noted that the specific embodiments are intended to explain the present invention rather than to limit it.

[0038] Terminology explanation:

[0039] PTMEG 2000: polytetrahydrofuran (molecular weight 2000), purchased from Aladdin Biochemical Technology Co., Ltd.;

[0040] HMDI: 4,4'-dicyclohexylmethane diisocyanate;

[0041] DBTDL: dibutyltin dilaurate, used as catalyst;

[0042] DMF: N,N-dimethylformamide;

[0043] BDA: 1,4-butanediamine;

[0044] ADH: adipic acid dihydrazide;

[0045] DABA: 4,4'-diaminobenzilide;

[0046] BDO: 1,4-butanediol;

[0047] Room temperature: has a meaning known in the art, generally refers to 25±2°C;

[0048] Mechanical properties test method: INSTRON 3344 electronic universal testing machine, cut the sample into a rectangular shape with a size of 25mm x 5mm x 0.6mm, and test at room temperature with a tensile rate of 50mm / min. Each sample is measured at least five times and the average value is taken;

[0049] UV aging test method: QUV / spray UV aging tester, light wavelength: 340nm, light intensity: 0.77W / m 2 , the cycle process conditions: UV irradiation at 60℃ for 8h, then condensation at 50℃ for 4h.

[0050] Fracture strength: the ratio of the tensile force to the fracture cross-sectional area when the material breaks, i.e. stress;

[0051] Elongation at break: When a material is stretched to break by an external force, the ratio of the elongation after stretching to the length before stretching is called elongation at break, expressed as a percentage;

[0052] Toughness: refers to the ability of a material to absorb energy during plastic deformation and fracture;

[0053] Dissipated energy: The portion of energy lost within a material that cannot provide useful work.

[0054] Example 1: Preparation of a mixed chain extender containing amino and hydrazine groups, wherein the molar ratio of ADH:BDA is 1:1 and the aliphatic colorless and transparent thermoplastic poly(urethane-urea)

[0055] 2.62g (0.01mol) HMDI, 10g (0.005mol) PTMEG2000, 150μL (0.00025mol) DBTDL and 22g anhydrous DMF were added to a 250mL round-bottom flask, and heated in an oil bath at 80℃ for 2h under magnetic stirring. 0.435g (0.0025mol) ADH and 0.22g (0.0025mol) BDA were dissolved in 20g anhydrous DMF. After the reaction was completed, the heating was turned off, and after the system was cooled to room temperature, a mixed DMF solution of ADH and BDA was added, and the reaction was carried out under magnetic stirring for 5h. Then, it was poured into a silicone mold for vacuum degassing. After degassing until no bubbles were generated, it was placed in an oven at 80℃ for 12h for drying, and then placed in a vacuum oven at 100 degrees for 8h to further remove residual DMF. The target aliphatic transparent thermoplastic poly (urethane-urea) elastomer was obtained by demolding. Denoted as SPU-HA.

[0056] Comparative Example 1: Preparation of aliphatic colorless transparent thermoplastic poly(urethane-urea) containing only amino chain extender

[0057] Add 2.62g HMDI, 10g PTMEG2000, 150μL DBTDL and 22g anhydrous DMF to a 250mL round-bottom flask, and heat in an oil bath at 80℃ for 2h under magnetic stirring. Dissolve 0.44g (0.005mol) BDA in 20g anhydrous DMF. Turn off the heating after the reaction, wait for the system to cool to room temperature, add the DMF solution of BDA, and react for 5h under magnetic stirring. Then pour it into a silicone mold for vacuum degassing. After degassing until no bubbles are generated, place it in an oven at 80℃ for 12h for drying, and then place it in a vacuum oven at 100 degrees for 8h to further remove residual DMF. Demolding gives the target aliphatic transparent thermoplastic poly(urethane-urea) elastomer. Recorded as SPU-A.

[0058] Comparative Example 2: Preparation of aliphatic colorless transparent thermoplastic poly(urethane-urea) containing only hydrazine chain extender

[0059] Add 2.62g HMDI, 10g PTMEG2000, 150μL DBTDL and 22g anhydrous DMF to a 250mL round-bottom flask, and heat in an oil bath at 80℃ for 2h under magnetic stirring. Dissolve 0.87g (0.005mol) ADH in 20g anhydrous DMF. Turn off the heating after the reaction, wait for the system to cool to room temperature, add the DMF solution of ADH, and react for 5h under magnetic stirring. Then pour it into a silicone mold for vacuum degassing. After degassing until no bubbles are generated, place it in an oven at 80℃ for 12h for drying, and then place it in a vacuum oven at 100 degrees for 8h to further remove residual DMF. Demolding gives the target aliphatic transparent thermoplastic poly(urethane-urea) elastomer. Recorded as SPU-H.

[0060] Comparative Example 3: Preparation of Transparent Thermoplastic Poly(urethane-urea) Containing Benzene Rings

[0061] Add 2.62g HMDI, 10g PTMEG2000, 150μL DBTDL and 22g anhydrous DMF to a 250mL round-bottom flask, and heat in an oil bath at 80℃ for 2h under magnetic stirring. Dissolve 0.435g (0.0025mol) ADH and 0.57g (0.0025mol) DABA in 20g anhydrous DMF. Turn off the heating after the reaction, wait for the system to cool to room temperature, add the mixed DMF solution of ADH and DABA, and react for 5h under magnetic stirring. Then pour into a silicone mold for vacuum degassing. After degassing until no bubbles are generated, place it in an oven at 80℃ for 12h for drying, and then place it in a vacuum oven at 100 degrees for 8h to further remove residual DMF. Demolding gives the target aliphatic transparent thermoplastic poly(urethane-urea) elastomer. Recorded as SPU-DA.

[0062] Comparative Example 4: Preparation of a mixed chain extender containing hydrazine and hydroxyl mismatched chain extenders, with ADH:BDO molar ratio of 1:1 and aliphatic colorless transparent thermoplastic poly(urethane-urea)

[0063] 2.62g HMDI, 10g PTMEG2000, 150μL DBTDL and 22g anhydrous DMF were added to a 250mL round-bottom flask, and heated in an oil bath at 80℃ for 2h under magnetic stirring. 0.435g (0.0025mol) ADH and 0.23g (0.0025mol) BDO were dissolved in 20g anhydrous DMF. After the reaction, the heating was turned off, and after the system cooled to room temperature, a mixed DMF solution of ADH and BDO was added, and the mixture was reacted for 5h under magnetic stirring. Then, it was poured into a silicone mold for vacuum degassing. After degassing until no bubbles were generated, it was placed in an oven at 80℃ for 12h for drying, and then placed in a vacuum oven at 100 degrees for 8h to further remove residual DMF. The target aliphatic transparent thermoplastic poly(urethane-urea) elastomer was obtained by demolding. It is recorded as SPU-HO.

[0064] Comparative Example 5: Preparation of a colorless, transparent, thermoplastic poly(urethane-urea) containing amino and hydroxy mismatched chain extenders, wherein the molar ratio of BDA:BDO is 1:1 and the mixed chain extender is

[0065] 2.62g HMDI, 10g PTMEG2000, 150μL DBTDL and 22g anhydrous DMF were added to a 250mL round-bottom flask, and heated in an oil bath at 80℃ for 2h under magnetic stirring. 0.22g (0.0025mol) BDA and 0.23g (0.0025mol) BDO were dissolved in 20g anhydrous DMF. After the reaction, the heating was turned off, and after the system cooled to room temperature, a mixed DMF solution of BDA and BDO was added, and the mixture was reacted for 5h under magnetic stirring. Then, it was poured into a silicone mold for vacuum degassing. After degassing until no bubbles were generated, it was placed in an oven at 80℃ for 12h for drying, and then placed in a vacuum oven at 100 degrees for 8h to further remove residual DMF. The target aliphatic transparent thermoplastic poly(urethane-urea) elastomer was obtained by demolding. It is recorded as SPU-AO.

[0066] Example 2: Preparation of a mixed chain extender containing amino and hydrazine groups, a colorless and transparent aliphatic thermoplastic poly(urethane-urea) with a molar ratio of ADH:BDA of 2:1

[0067] 2.62g (0.01mol) HMDI, 10g (0.005mol) PTMEG2000, 150μL (0.00025mol) DBTDL and 22g anhydrous DMF were added to a 250mL round-bottom flask, and heated in an oil bath at 80℃ for 2h under magnetic stirring. 0.581g (0.0033mol) ADH and 0.15g (0.0017mol) BDA were dissolved in 20g anhydrous DMF. After the reaction was completed, the heating was turned off, and after the system was cooled to room temperature, a mixed DMF solution of ADH and BDA was added, and the reaction was carried out under magnetic stirring for 5h. Then, it was poured into a silicone mold for vacuum degassing. After degassing until no bubbles were generated, it was placed in an oven at 80℃ for 12h for drying, and then placed in a vacuum oven at 100 degrees for 8h to further remove the residual DMF. The target aliphatic transparent thermoplastic poly (urethane-urea) elastomer was obtained by demolding. Denoted as SPU-H2A.

[0068] Example 3: Preparation of a mixed chain extender containing amino and hydrazine mismatched chain extenders, ADH:BDA molar ratio of 1:2, aliphatic colorless transparent thermoplastic poly (urethane-urea)

[0069] 2.62g (0.01mol) HMDI, 10g (0.005mol) PTMEG2000, 150μL (0.00025mol) DBTDL and 22g anhydrous DMF were added to a 250mL round-bottom flask, and heated in an oil bath at 80℃ for 2h under magnetic stirring. 0.29g (0.0017mol) ADH and 0.29g (0.0033mol) BDA were dissolved in 20g anhydrous DMF. After the reaction was completed, the heating was turned off, and after the system was cooled to room temperature, a mixed DMF solution of ADH and BDA was added, and the reaction was carried out under magnetic stirring for 5h. Then, it was poured into a silicone mold for vacuum degassing. After degassing until no bubbles were generated, it was placed in an oven at 80℃ for 12h for drying, and then placed in a vacuum oven at 100 degrees for 8h to further remove residual DMF. The target aliphatic transparent thermoplastic poly (urethane-urea) elastomer was obtained by demolding. Denoted as SPU-HA2.

[0070] Test example

[0071] Figure 1 This is a comparison of the mechanical properties and surface morphology after long-term ultraviolet irradiation of benzene ring-containing elastomers and benzene ring-free elastomers reported in the literature. As can be seen from the figure, although the mechanical properties of materials containing benzene rings are much better than those of elastomers without benzene rings, and the toughness value is even twice that of elastomers without benzene rings, they will become darker in color or even opaque after long-term ultraviolet exposure, thus degrading and endangering safety of use. Elastomers without benzene rings will not change color under ultraviolet irradiation, and will not affect their use.

[0072] Figure 2The figure is a bar graph of toughness data of three elastomers containing mismatched hydrazine and amino groups (SPU-HA, Example 1), mismatched hydrazine and hydroxyl groups (SPU-HO, Comparative Example 4), and mismatched amino and hydroxyl groups (SPU-AO, Comparative Example 5). As can be seen from the figure, the toughness of the elastomer in Example 1 is 1086.9 MJ m -3 , while the toughness of the elastomer in Comparative Example 4 is 641.6 MJ m -3 The toughness of the elastomer in comparative example 5 is 370.7 MJ m -3 Therefore, the elastomer containing mismatched hydrazine and amino groups exhibits the best mechanical properties, which may be due to the stronger binding force between the two, resulting in lower binding energy, and containing more and stronger hydrogen bonding forces.

[0073] Figure 3 The figure is a bar graph of toughness data of five elastomers: Example 1 (SPU-HA), Comparative Example 1 (SPU-A), Comparative Example 2 (SPU-H), Example 2 (SPU-H2A), and Example 3 (SPU-HA2). As can be seen from the figure, the toughness of the elastomer in Example 1 is 1086.9 MJ m -3 , while the toughness of the elastomer in Comparative Example 1 is 179.4 MJ m -3 The toughness of the elastomer in Comparative Example 2 is 364.5 MJ m -3 The toughness of the elastomer in Example 2 is 550.1 MJ m -3 The toughness of the elastomer in Example 3 is 438.7 MJ m -3 Therefore, the elastomer containing a mismatch ratio of hydrazine and amino groups of 1:1 exhibits the best mechanical properties, which is due to more mismatch supramolecular effects.

[0074] Figure 4 The hydrazine and amino mismatched benzene ring-free elastomer SPU-HA prepared in Example 1 is similar to the toughness>300MJ m reported in the current literature. -3 Comparison of mechanical properties of benzene ring-free elastomers. As can be seen from the figure, due to the mismatch between the hydrazine group and the amino group, SPU-HA achieves a balance between high mechanical properties and colorless transparency.

[0075] Figure 5 The SPU-DA containing benzene ring prepared in Example 3 and the SPU-HA without benzene ring prepared in Example 1 were aged (QUV / spray ultraviolet aging tester, light wavelength: 340nm, light intensity: 0.77W / m 2 , Cycle process conditions: UV irradiation at 60℃ for 8h, then condensation at 50℃ for 4h) After different days, the transparency change bar graph. As can be seen from the figure, the transparency of SPU-DA containing benzene rings drops sharply, while the transparency of SPU-HA remains stable.

Claims

1. A method for preparing a colorless and transparent poly(urethane-urea) elastomer based on mismatch supramolecular action, comprising the steps of: (1) In a solvent and under the action of a catalyst, diisocyanate and oligomer polyol react to form a prepolymer; (2) mixing an organic solution of an aliphatic mixed chain extender with a prepolymer, reacting, degassing, and drying to obtain a colorless and transparent poly(urethane-urea) elastomer based on mismatch supramolecular action; The aliphatic mixed chain extender is a combination of adipic acid dihydrazide and 1,4-butanediamine; the molar ratio of adipic acid dihydrazide to 1,4-butanediamine is 1:

1.

2. The method for preparing a colorless and transparent poly(urethane-urea) elastomer based on mismatch supramolecular action according to claim 1, wherein step (1) comprises one or more of the following conditions: i. The solvent is one or a combination of two or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide or N-methylpyrrolidone; the mass ratio of diisocyanate to solvent is 1:5-20; ii. The catalyst is one or a combination of two or more of dibutyltin dilaurate, stannous octoate or triethylenediamine; the molar ratio of the catalyst to the diisocyanate is 0.01-0.05:

1.

3. The method for preparing a colorless and transparent poly(urethane-urea) elastomer based on mismatch supramolecular action according to claim 1, wherein step (1) comprises one or more of the following conditions: i. The diisocyanate is 4,4'-dicyclohexylmethane diisocyanate or isophorone diisocyanate; ii. The oligomer polyol is one or a combination of two or more of polytetrahydrofuran, polydimethylsiloxane or polycaprolactone; iii. The molar ratio of diisocyanate to oligomer polyol is 1:0.2-1.

4. According to the method for preparing a colorless and transparent poly(urethane-urea) elastomer based on mismatch supramolecular action according to claim 1, in step (1), the reaction temperature of diisocyanate and oligomer polyol is 60-100° C., the reaction time is 1-3 h, and the reaction is carried out under stirring conditions.

5. The method for preparing a colorless and transparent poly(urethane-urea) elastomer based on mismatch supramolecular action according to claim 1, wherein step (2) comprises one or more of the following conditions: i. The mass concentration of the organic solution of the aliphatic mixed chain extender is 1-5%; the solvent used for the organic solution of the aliphatic mixed chain extender is one or a combination of two or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide or N-methylpyrrolidone; ii. The molar amount of the aliphatic mixed chain extender is 40-60% of the molar amount of the diisocyanate.

6. The method for preparing a colorless and transparent poly(urethane-urea) elastomer based on mismatch supramolecular action according to claim 1, wherein step (2) comprises one or more of the following conditions: i. The reaction temperature is room temperature, the reaction time is 2-7h, and the reaction is carried out under stirring conditions; ii. The degassing method is vacuum degassing; the drying conditions are: drying at 70-90°C for 10-14h, and then vacuum drying at 90-110°C for 6-10h.

7. A colorless and transparent poly(urethane-urea) elastomer based on mismatch supramolecular action, prepared by the method according to any one of claims 1 to 6.

8. Application of the colorless and transparent poly(urethane-urea) elastomer based on mismatch supramolecular action as claimed in claim 7 in the field of UV-resistant, high mechanical strength, damage-resistant, and recyclable transparent materials.

Images