Method for synergistically toughening thermoplastic poly(urethane-urea) by using rigid-flexible supramolecular segments and application thereof

Abstract

The present invention relates to the technical field of synthesis of high-performance polymer materials, and particularly to a method for synergistically toughening thermoplastic poly(urethane-urea) by using rigid-flexible supramolecular segments and its application. In the present invention, two kinds of mixed chain extenders capable of forming rigid and flexible supramolecular interactions are added in the post-stage of prepolymer formation during the synthesis of thermoplastic poly(urethane-urea) materials, and the rigid and flexible supramolecular interactions within the polymer chains are hybridized, so that when the material bears external stress, it can effectively dissipate the energy applied by the external force, thereby improving the toughness of the material, and its value is the highest in the world at present. In addition, the material also has the highest true fracture stress and the highest fracture energy in the world, has remarkable damage resistance, good resilience, good reparability and recyclability, and at the same time has low production cost and high practical applicability.

Description

Technical Field

[0001] The present invention relates to the technical field of high-performance polymer material synthesis, and specifically relates to a method for synergistically toughening thermoplastic poly(urethane-urea) using rigid-flexible supramolecular segments and its application. Background Art

[0002] Disclosing the information of this background art section is only intended to increase the understanding of the overall background of the present invention, and does not necessarily be regarded as an admission or imply in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] Toughness is generally defined as the ability of a material to absorb energy during plastic deformation and fracture. High toughness of a material requires a balance between strength and ductility. Compared with inorganic non-metallic materials and metallic materials, traditional polymers have lower strength, resulting in limited applications. Especially for thermoplastic poly(urethane-urea), due to its internal linear structure, its stability is not as good as that of thermosetting poly(urethane-urea) with a crosslinked structure. However, due to the advantages of recyclability and good stretchability of thermoplastic poly(urethane-urea), it has been widely used in fields such as biomedicine, anti-impact devices, and flexible electronic devices. Therefore, improving the toughness of thermoplastic poly(urethane-urea) is crucial and is the future development trend.

[0004] The inventors' research found that although supramolecular interactions are now widely used to toughen, that is, introducing supramolecular interactions into the molecular structure of thermoplastic poly(urethane-urea) to improve its toughness, and a series of effects have been achieved. However, through careful study of the previous molecular designs, it was found that their utilization of supramolecular interactions was too random due to the lack of relevant theoretical guidance. The multiple bindings of the widely used non-specific supramolecular segments may lead to excessive supramolecular aggregation, making it difficult for supramolecular interactions to dissociate and recombine when the material is subjected to external forces, and difficult to dissipate energy, thus unable to resist damage. Summary of the Invention

[0005] In order to solve the problems of the urgently needed improvement of the toughness of thermoplastic poly(urethane-urea) and the current lack of theoretical guidance for design, the present invention proposes a method for synergistically toughening thermoplastic poly(urethane-urea) using rigid-flexible supramolecular segments and its application. Mixing two chain extenders that can form rigid supramolecular interactions and flexible supramolecular interactions to form supramolecular interactions with low matching degree, eliminating the phenomenon of excessive supramolecular aggregation. By regulating this supramolecular interaction, the energy dissipation ability and toughness of the elastomer can be improved without sacrificing its strength and elasticity. In addition, this supramolecular interaction with low matching degree also endows poly(urethane-urea) with other excellent mechanical properties, with low production costs and high practical applicability.

[0006] Specifically, the present invention is achieved by the following technical solutions:

[0007] In the first aspect of the present invention, a method for toughening thermoplastic poly(urethane-urea) by the synergistic effect of rigid-flexible supramolecular segments is provided, including: adding a mixed chain extender after the formation of the prepolymer during the synthesis of thermoplastic poly(urethane-urea).

[0008] According to the present invention, preferably, the prepolymer comprises at least one polyurethane prepolymer obtained by reacting a diisocyanate and an oligomeric diol under the action of a catalyst;

[0009] More preferably, the diisocyanate is selected from one or more of 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate;

[0010] More preferably, the oligomeric diol is selected from one or more of polytetrahydrofuran, polycaprolactone diol, polyethylene glycol, polypropylene glycol, with an average molecular weight of 1000 - 10000 g / mol;

[0011] According to the present invention, preferably, the mixed chain extender is a mixed chain extender containing both a rigid chain extender and a flexible chain extender;

[0012] More preferably, the rigid chain extender is selected from one or more of 4,4'-diaminobenzanilide, N1,N4-bis(4-aminophenyl)terephthalamide, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylmethane, p-phenylenediamine, 4,4'-diaminodiphenyl ether, isophthalic dihydrazide; the flexible chain extender is selected from one or more of 1,4-butanediol, 1,4-butanediamine, adipic dihydrazide;

[0013] According to the present invention, preferably, the mixed chain extender accounts for 2 - 7% of the mass of the raw materials of thermoplastic poly(urethane-urea).

[0014] According to the present invention, preferably, the mixed chain extender is added in the form of a solution after the formation of the thermoplastic poly(urethane-urea) prepolymer;

[0015] More preferably, the solvent of the mixed chain extender solution is an organic solvent, selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone.

[0016] According to the present invention, preferably, the method for toughening thermoplastic poly(urethane-urea) by the synergistic effect of rigid-flexible supramolecular segments includes the following steps:

[0017] (1) Reacting a diisocyanate and an oligomeric polyol under the action of a catalyst to form a polyurethane prepolymer;

[0018] (2) Mix the organic solution of the mixed chain extender with the thermoplastic polyurethane prepolymer, heat and react, and dry the solvent to obtain a thermoplastic poly(urethane-urea) elastomer.

[0019] According to the present invention, preferably, the heating temperature for the reaction of the chain extender and the prepolymer is 30-60 °C, and the reaction time is 1.5-8 h.

[0020] According to the present invention, preferably, a vacuum defoaming step is also carried out after the heating reaction is completed.

[0021] In the second aspect of the present invention, there is provided a rigid-flexible supramolecular synergistically toughened thermoplastic poly(urethane-urea) elastomer prepared by a method of using rigid-flexible supramolecular segments to synergistically toughen thermoplastic poly(urethane-urea).

[0022] In the third aspect of the present invention, there is provided an application of the rigid-flexible supramolecular synergistically toughened thermoplastic poly(urethane-urea) in the fields of buffer and shock-absorbing materials, anti-impact coating protection materials, military and police sports products.

[0023] For those not elaborated in the present invention, they are all in accordance with the existing technologies in the art.

[0024] One or more of the above technical solutions of the present invention have the following beneficial effects:

[0025] 1) Due to the adoption of the above technical solution, the present invention adds a new mixed chain extender based on the original production process of thermoplastic poly(urethane-urea), realizing the toughening of thermoplastic poly(urethane-urea).

[0026] 2) If a single chain extender that cannot form supramolecular interactions or can only form supramolecular interactions with a fixed stoichiometric ratio is introduced, the toughness of the prepared poly(urethane-urea) is not strong; if a single chain extender that can form supramolecular interactions with a non-fixed stoichiometric ratio is introduced, excessive aggregation of supramolecular segments will occur, making it difficult for the supramolecular interactions to dissociate and recombine in a timely manner when the material is subjected to external forces, and it is difficult to dissipate energy, so it cannot resist damage. Therefore, in some technical solutions of the present invention, rigid and flexible mixed chain extenders are introduced into thermoplastic poly(urethane-urea), and the rigid and flexible supramolecular interactions cross to form supramolecular interactions with a low degree of matching, which can disperse the excessive stacking effect caused by a single supramolecular interaction, and can dissociate and recombine in a timely manner under the drive of external forces to dissipate energy and achieve toughening.

[0027] 3) The method for using rigid-flexible supramolecular segments to synergistically toughen thermoplastic poly(urethane-urea) provided by the technical solution of the present invention is simple and easy to implement, the raw materials are easily available, the cost is low, and the requirements for reaction conditions and equipment used are not high. The mixed chain extender selected in the technical solution of the present invention has a wide range of uses and can be added to various types of polymer materials. Description of the Drawings

[0028] The accompanying drawings of the specification, which form a part of the present invention, are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein:

[0029] Figure 1 It is the orientation of the polymer molecular chains containing a single supramolecular chain extender and a rigid-flexible supramolecular mixed chain extender when subjected to external force stretching.

[0030] Figure 2 It is a comparison of the mechanical properties of the polymers prepared with a single rigid chain extender, a single flexible chain extender, and a rigid-flexible mixed chain extender in Comparative Example 1, Comparative Example 8, and Example 1.

[0031] Figure 3 a-c are schematic diagrams of cyclic tensile tests with variable strain of the polymers prepared with a single rigid chain extender, a single flexible chain extender, and a rigid-flexible mixed chain extender in Comparative Example 1, Comparative Example 8, and Example 1. 100% represents a maximum strain of 100%, 200% represents a maximum strain of 200%, 300% represents a maximum strain of 300%, 400% represents a maximum strain of 400%, 500% represents a maximum strain of 500%, 600% represents a maximum strain of 600%, 800% represents a maximum strain of 800%, 1000% represents a maximum strain of 1000%, 1200% represents a maximum strain of 1200%, 1400% represents a maximum strain of 1400%, and 1800% represents a maximum strain of 1800%. Figure 3 d is a numerical summary of the integral area (dissipated energy) of each hysteresis loop in Figures a-c.

[0032] Figure 4 It is a mechanical comparison chart of the repair ability of the polymer containing a mixed chain extender prepared in Example 1. Detailed Embodiments

[0033] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. The experimental methods without specific conditions noted in the following embodiments are generally in accordance with conventional conditions or conditions recommended by the manufacturer.

[0034] 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. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0035] With the wide application of thermoplastic poly(urethane-urea) in actual production and life, it is urgent to improve the mechanical properties such as toughness of thermoplastic poly(urethane-urea). Solving this problem helps to develop a circular economy and achieve the goal of sustainable development. In fact, appropriate molecular design can endow the thermoplastic poly(urethane-urea) with strong supramolecular interactions inside the molecules, enabling them to act as sacrificial bonds under external stress, dissipate energy, and thus achieve toughening. This method does not significantly increase the cost and has become one of the most feasible methods for toughening thermoplastic poly(urethane-urea).

[0036] To solve the problem that the toughness of thermoplastic poly(urethane-urea) urgently needs to be improved and the current molecular design by researchers is too random so that the improvement trend is relatively slow, the present invention proposes a method and its application for synergistically toughening thermoplastic poly(urethane-urea) using rigid-flexible supramolecular segments. It is composed of a mixture of two chain extenders that can form rigid supramolecular interactions and flexible supramolecular interactions, enabling the hybridized rigid-flexible supramolecules to better act as sacrificial bonds and dissipate energy when the material is under external stress, thereby toughening thermoplastic poly(urethane-urea). In addition, it also endows poly(urethane-urea) with other excellent mechanical properties, has a low production cost, and has high practical applicability.

[0037] Specifically, the present invention is realized through the following technical solutions:

[0038] In the first aspect of the present invention, there is provided a method for synergistically toughening thermoplastic poly(urethane-urea) using rigid-flexible supramolecular segments, which is characterized in that it includes: adding a mixed chain extender in the post-prepolymer formation stage during the synthesis of thermoplastic poly(urethane-urea).

[0039] If a single chain extender that cannot form supramolecular interactions or can only form supramolecular interactions with a fixed stoichiometry is introduced, the resulting poly(urethane-urea) has poor toughness; if a single chain extender that can form supramolecular interactions with a non-fixed stoichiometry is introduced, excessive aggregation of supramolecular interactions occurs, making it difficult for the supramolecular interactions to dissociate and recombine in a timely manner when the material is under external force, and it is difficult to dissipate energy, so it cannot resist damage and achieve toughening, losing its original value. The present invention uses a rigid-flexible mixed chain extender to toughen thermoplastic poly(urethane-urea). The cross of rigid and flexible supramolecular interactions can disperse the aggregation effect caused by a single chain extender, and can dissociate and recombine in a timely manner under the drive of external force, dissipate energy, achieve toughening, and will not significantly change the original process, which has good feasibility from both technical and cost perspectives.

[0040] In one or more embodiments of the present invention, the prepolymer includes at least one polyurethane prepolymer obtained by reacting a diisocyanate and an oligomeric diol under the action of a catalyst;

[0041] In one or more embodiments of the present invention, the diisocyanate is selected from one or more of 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate;

[0042] In one or more embodiments of the present invention, the oligomer diol is selected from one or more of polytetrahydrofuran, polycaprolactone diol, polyethylene glycol, polypropylene glycol, and has an average molecular weight of 1000-10000 g / mol;

[0043] In one or more embodiments of the present invention, the mixed chain extender is a mixed chain extender that contains both a rigid chain extender and a flexible chain extender;

[0044] In one or more embodiments of the present invention, the rigid chain extender is selected from one or more of 4,4'-diaminobenzanilide, N1,N4-bis(4-aminophenyl) terephthalamide, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylmethane, p-phenylenediamine, 4,4'-diaminodiphenyl ether, isophthaloyl hydrazide; the flexible chain extender is selected from one or more of 1,4-butanediol, 1,4-butanediamine, adipic dihydrazide;

[0045] Figure 2 It is a comparison of the mechanical properties of thermoplastic poly(urethane-urea) obtained by using a single chain extender and a rigid-flexible mixed chain extender in a thermoplastic poly(urethane-urea) system. As can be seen from the figure, the breaking strength, elongation at break, and toughness of the thermoplastic poly(urethane-urea) using the rigid-flexible mixed chain extender are significantly higher than those of the thermoplastic poly(urethane-urea) using a single chain extender.

[0046] In one or more embodiments of the present invention, the chain extender used is a mixed chain extender of a rigid chain extender and a flexible chain extender. As mentioned above, the toughness of the thermoplastic poly(urethane-urea) prepared using a single rigid or single flexible chain extender is not as high as that of the mixed chain extender. Therefore, in some embodiments, the chain extender selected is a rigid-flexible mixed chain extender.

[0047] Preferably, the mixed chain extender accounts for 2-7% of the mass of the raw materials of the thermoplastic poly(urethane-urea).

[0048] In one or more embodiments of the present invention, the mixed chain extender is added in the form of a solution after the formation of the thermoplastic poly(urethane-urea) prepolymer.

[0049] In one or more embodiments of the present invention, the solvent of the mixed chain extender solution is an organic solvent, selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone.

[0050] Adding a dispersion of a mixed chain extender in the later stage of the formation of a thermoplastic poly(urethane-urea) prepolymer is beneficial to controlling the reaction temperature, reducing side reactions, and improving product performance.

[0051] In one or more embodiments of the present invention, it specifically includes:

[0052] (1) A diisocyanate and an oligomeric polyol react under the action of a catalyst to form a polyurethane prepolymer;

[0053] (2) Mix an organic solution of the mixed chain extender with the thermoplastic polyurethane prepolymer, heat and react, and dry to obtain a thermoplastic poly(urethane-urea) elastomer.

[0054] In one or more embodiments of the present invention, the heating temperature for the reaction of the chain extender and the prepolymer is 30 - 60 °C, and the reaction time is 1.5 - 8 h.

[0055] Within this temperature and time range, it can be ensured that the mixed chain extender and the prepolymer of thermoplastic poly(urethane-urea) are fully mixed and reacted; too high a temperature may lead to too fast a reaction rate and an uneven system, and too low a temperature may make the reaction time too long or fail to trigger the reaction, thus unable to ensure ideal reaction progress.

[0056] In the second aspect of the present invention, there is provided a rigid-flexible supramolecular synergistically toughened thermoplastic poly(urethane-urea) prepared by a method of using rigid-flexible supramolecular segments to synergistically toughen thermoplastic poly(urethane-urea).

[0057] In the third aspect of the present invention, there is provided an application of the rigid-flexible supramolecular synergistically toughened thermoplastic poly(urethane-urea) in the fields of buffer and shock-absorbing materials, anti-impact coating protection materials, and military and police sports products.

[0058] The following combines specific examples to further elaborate on the present invention in detail. It should be noted that the specific examples are explanations rather than limitations of the present invention.

[0059] Term explanation:

[0060] PTMEG2000: Polytetrahydrofuran (molecular weight 2000 g / mol), purchased from Aladdin Biochemical Technology Co., Ltd.;

[0061] PCL2000: Polycaprolactone diol (molecular weight 2000 g / mol), purchased from Aladdin Biochemical Technology Co., Ltd.;

[0062] PEG2000: Polyethylene glycol (molecular weight 2000 g / mol), purchased from Aladdin Biochemical Technology Co., Ltd.;

[0063] PPG 2000: Polypropylene glycol (molecular weight 2000 g / mol), purchased from Aladdin Biochemical Technology Co., Ltd.;

[0064] HMDI: 4,4'-Dicyclohexylmethane diisocyanate, purchased from Aladdin Biochemical Technology Co., Ltd.;

[0065] IPDI: Isophorone diisocyanate, purchased from Aladdin Biochemical Technology Co., Ltd.;

[0066] HDI: Hexamethylene diisocyanate, purchased from Aladdin Biochemical Technology Co., Ltd.;

[0067] MDI: Diphenylmethane diisocyanate, purchased from Aladdin Biochemical Technology Co., Ltd.;

[0068] DBTDL: Dibutyltin dilaurate, used as a catalyst, purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.;

[0069] DMF: N,N-Dimethylformamide, a common organic solvent;

[0070] DMSO: Dimethyl sulfoxide, a common organic solvent;

[0071] THF: Tetrahydrofuran, a common organic solvent;

[0072] CHCl3: Trichloromethane, also known as chloroform, a common organic solvent;

[0073] DABA: 4,4'-Diaminobenzanilide, purchased from Aladdin Biochemical Technology Co., Ltd.;

[0074] NBAT: N 1 ,N 4 ,N-Bis(4-aminophenyl) terephthalamide, customized by BioDuro-Sundia Medical Technology (Shanghai) Co., Ltd.;

[0075] BAM: 4,4'-Diaminobenzophenone, purchased from Aladdin Biochemical Technology Co., Ltd.;

[0076] EDA: 4,4'-Diaminodiphenylmethane, purchased from Aladdin Biochemical Technology Co., Ltd.;

[0077] PPDA: p-Phenylenediamine, purchased from Aladdin Biochemical Technology Co., Ltd.;

[0078] ODA: 4,4'-Diaminodiphenyl ether, purchased from Aladdin Biochemical Technology Co., Ltd.;

[0079] IPDH: Isophthaloyl hydrazide, purchased from TCI (Shanghai) Chemical Industry Development Co., Ltd.;

[0080] ADH: Diadipic dihydrazide, purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.;

[0081] BDO: 1,4-Butanediol, purchased from Aladdin Biochemical Technology Co., Ltd.;

[0082] BDA: 1,4-Butanediamine, purchased from Aladdin Biochemical Technology Co., Ltd.;

[0083] NMP: N-Methylpyrrolidone, purchased from Aladdin Biochemical Technology Co., Ltd.;

[0084] Room temperature: It has the meaning well-known in the technical field, generally referring to 25 ± 2 °C;

[0085] Mechanical property test method: INSTRON 3344 electronic universal testing machine. Cut the specimen into a rectangular shape with dimensions of 25 mm × 5 mm × 0.6 mm. Conduct the test at room temperature with a tensile rate of 50 mm / min. Measure each specimen at least five times and take the average value;

[0086] Breaking strength: The ratio of the tensile force at which the material breaks to the cross-sectional area at the break, i.e., stress;

[0087] Elongation at break: When the material is subjected to an external force until it breaks, the ratio of the elongated length after stretching to the length before stretching is called the elongation at break, expressed as a percentage;

[0088] Toughness: It represents the ability of the material to absorb energy during plastic deformation and rupture;

[0089] Dissipated energy: The part of the energy lost inside the material that cannot provide useful work.

[0090] Comparative Example 1: Preparation of thermoplastic poly(urethane-urea) with DABA as the sole chain extender

[0091] Add 2.63 g of HMDI, 10 g of PTMEG2000, 140 μL of DBTDL, and 15 g of anhydrous DMF into a 100 mL round-bottom flask. Under magnetic stirring, heat in an 80 °C oil bath for 3 h. Dissolve 1.1363 g of DABA in 15 g of anhydrous DMF. After the reaction is completed and cooled to 45 °C, add the DMF solution of DABA and react for 3 h under magnetic stirring. Pour it into a glass dish for defoaming. After defoaming until no more bubbles are generated, place it in an oven at 90 °C for curing for 12 h, and demold to obtain the target thermoplastic poly(urethane-urea) elastomer.

[0092] Comparative Example 2: Preparation of thermoplastic poly(urethane-urea) with NBAT as the sole chain extender

[0093] Add 2.63 g of HMDI, 10 g of PTMEG2000, 140 μL of DBTDL and 15 g of anhydrous DMF into a 100 mL round-bottom flask. Under magnetic stirring, heat it in an 80 °C oil bath for 3 h. Dissolve 1.732 g of NBAT in 15 g of anhydrous DMF. After the reaction is completed and cooled to 45 °C, add the DMF solution of NBAT, and react for 3 h under magnetic stirring. Pour it into a glass dish for defoaming. After defoaming until no more bubbles are generated, place it in an oven at 90 °C for curing for 12 h, and demold to obtain the target thermoplastic poly(urethane-urea) elastomer.

[0094] Comparative Example 3: Preparation of thermoplastic poly(urethane-urea) with BAM as the single chain extender

[0095] Add 2.63 g of HMDI, 10 g of PTMEG2000, 140 μL of DBTDL and 15 g of anhydrous DMF into a 100 mL round-bottom flask. Under magnetic stirring, heat it in an 80 °C oil bath for 3 h. Dissolve 1.06 g of BAM in 15 g of anhydrous DMF. After the reaction is completed and cooled to 45 °C, add the DMF solution of BAM, and react for 3 h under magnetic stirring. Pour it into a glass dish for defoaming. After defoaming until no more bubbles are generated, place it in an oven at 90 °C for curing for 12 h, and demold to obtain the target thermoplastic poly(urethane-urea) elastomer.

[0096] Comparative Example 4: Preparation of thermoplastic poly(urethane-urea) with EDA as the single chain extender

[0097] Add 2.63 g of HMDI, 10 g of PTMEG2000, 140 μL of DBTDL and 10 g of anhydrous DMF into a 100 mL round-bottom flask. Under magnetic stirring, heat it in an 80 °C oil bath for 3 h. Dissolve 1.0 g of EDA in 15 g of anhydrous DMF. After the reaction is completed and cooled to 45 °C, add the DMF solution of EDA, and react for 3 h under magnetic stirring. Pour it into a glass dish for defoaming. After defoaming until no more bubbles are generated, place it in an oven at 90 °C for curing for 12 h, and demold to obtain the target thermoplastic poly(urethane-urea) elastomer.

[0098] Comparative Example 5: Preparation of thermoplastic poly(urethane-urea) with PPDA as the single chain extender

[0099] Add 2.63 g of HMDI, 10 g of PTMEG2000, 140 μL of DBTDL and 10 g of anhydrous DMF into a 100 mL round-bottom flask. Under magnetic stirring, heat it in an 80 °C oil bath for 3 h. Dissolve 0.54 g of PPDA in 15 g of anhydrous DMF. After the reaction is completed and cooled to 45 °C, add the DMF solution of PPDA, and react for 3 h under magnetic stirring. Pour it into a glass dish for defoaming. After defoaming until no more bubbles are generated, place it in an oven at 90 °C for curing for 12 h, and demold to obtain the target thermoplastic poly(urethane-urea) elastomer.

[0100] Comparative Example 6: Preparation of thermoplastic poly(urethane-urea) with ODA as the sole chain extender

[0101] Add 2.63 g of HMDI, 10 g of PTMEG2000, 140 μL of DBTDL and 15 g of anhydrous DMF into a 100 mL round-bottom flask. Under magnetic stirring, heat in an 80 °C oil bath for 3 h. Dissolve 1.0 g of ODA in 15 g of anhydrous DMF. After the reaction is completed and cooled to 45 °C, add the DMF solution of ODA, and react for 3 h under magnetic stirring. Pour it into a glass dish for defoaming. After defoaming until no more bubbles are generated, place it in an oven at 90 °C for curing for 12 h, and demold to obtain the target thermoplastic poly(urethane-urea) elastomer.

[0102] Comparative Example 7: Preparation of thermoplastic poly(urethane-urea) with IPDA as the sole chain extender

[0103] Add 2.63 g of HMDI, 10 g of PTMEG2000, 140 μL of DBTDL and 15 g of anhydrous DMF into a 100 mL round-bottom flask. Under magnetic stirring, heat in an 80 °C oil bath for 3 h. Dissolve 0.98 g of IPDA in 15 g of anhydrous DMF. After the reaction is completed and cooled to 45 °C, add the DMF solution of IPDA, and react for 3 h under magnetic stirring. Pour it into a glass dish for defoaming. After defoaming until no more bubbles are generated, place it in an oven at 90 °C for curing for 12 h, and demold to obtain the target thermoplastic poly(urethane-urea) elastomer.

[0104] Comparative Example 8: Preparation of thermoplastic poly(urethane-urea) with ADH as the sole chain extender

[0105] Add 2.63 g of HMDI, 10 g of PTMEG2000, 140 μL of DBTDL and 15 g of anhydrous DMF into a 100 mL round-bottom flask. Under magnetic stirring, heat in an 80 °C oil bath for 3 h. Dissolve 0.871 g of ADH in 30 g of anhydrous DMF. After the reaction is completed and cooled to 45 °C, add the DMF solution of ADH, and react for 3 h under magnetic stirring. Pour it into a glass dish for defoaming. After defoaming until no more bubbles are generated, place it in an oven at 90 °C for curing for 12 h, and demold to obtain the target thermoplastic poly(urethane-urea) elastomer.

[0106] Comparative Example 9: Preparation of thermoplastic poly(urethane-urea) with BDO as the sole chain extender

[0107] Add 2.63 g of HMDI, 10 g of PTMEG2000, 140 μL of DBTDL and 15 g of anhydrous DMF into a 100 mL round-bottom flask. Under magnetic stirring, heat in an oil bath at 80 °C for 3 h. Dissolve 0.45 g of BDO in 15 g of anhydrous DMF. After the reaction is completed and cooled to 45 °C, add the DMF solution of BDO, and react for 3 h under magnetic stirring. Pour it into a glass dish for defoaming. After defoaming until no more bubbles are generated, place it in an oven at 90 °C for curing for 12 h, and demold to obtain the target thermoplastic poly(urethane-urea) elastomer.

[0108] Comparative Example 10: Preparation of thermoplastic poly(urethane-urea) with BDA as the sole chain extender

[0109] Add 2.63 g of HMDI, 10 g of PTMEG2000, 140 μL of DBTDL and 15 g of anhydrous DMF into a 100 mL round-bottom flask. Under magnetic stirring, heat in an oil bath at 80 °C for 3 h. Dissolve 0.44 g of BDA in 15 g of anhydrous DMF. After the reaction is completed and cooled to 45 °C, add the DMF solution of BDA, and react for 3 h under magnetic stirring. Pour it into a glass dish for defoaming. After defoaming until no more bubbles are generated, place it in an oven at 90 °C for curing for 12 h, and demold to obtain the target thermoplastic poly(urethane-urea) elastomer.

[0110] Example 1: Preparation of thermoplastic poly(urethane-urea) with DABA and ADH as the mixed chain extenders

[0111] Add 2.63 g of HMDI, 10 g of PTMEG2000, 140 μL of DBTDL and 15 g of anhydrous DMF into a 100 mL round-bottom flask. Under magnetic stirring, heat in an oil bath at 80 °C for 3 h. Dissolve 0.568 g of DABA and 0.44 g of ADH in 30 g of anhydrous DMF. After the reaction is completed and cooled to 45 °C, add the mixed DMF solution of DABA and ADH, and react for 3 h under magnetic stirring. Pour it into a glass dish for defoaming. After defoaming until no more bubbles are generated, place it in an oven at 90 °C for curing for 12 h, and demold to obtain the target thermoplastic poly(urethane-urea) elastomer.

[0112] Example 2: Preparation of thermoplastic poly(urethane-urea) with NBAT and ADH as the mixed chain extenders

[0113] Add 2.63 g of HMDI, 10 g of PTMEG2000, 140 μL of DBTDL and 15 g of anhydrous DMF into a 100 mL round-bottom flask. Under magnetic stirring, heat it in an 80 °C oil bath for 3 h. Dissolve 0.866 g of NBAT and 0.44 g of ADH in 30 g of anhydrous DMF. After the reaction is completed and cooled to 45 °C, add the mixed DMF solution of NBAT and ADH, and react for 3 h under magnetic stirring. Pour it into a glass dish for defoaming. After defoaming until no more bubbles are generated, place it in an oven at 90 °C for curing for 12 h, and demold to obtain the target thermoplastic poly(urethane-urea) elastomer.

[0114] Example 3: Preparation of thermoplastic poly(urethane-urea) using BAM and ADH as mixed chain extenders

[0115] Add 2.63 g of HMDI, 10 g of PTMEG2000, 140 μL of DBTDL and 15 g of anhydrous DMF into a 100 mL round-bottom flask. Under magnetic stirring, heat it in an 80 °C oil bath for 3 h. Dissolve 0.53 g of BAM and 0.44 g of ADH in 30 g of anhydrous DMF. After the reaction is completed and cooled to 45 °C, add the mixed DMF solution of BAM and ADH, and react for 3 h under magnetic stirring. Pour it into a glass dish for defoaming. After defoaming until no more bubbles are generated, place it in an oven at 90 °C for curing for 12 h, and demold to obtain the target thermoplastic poly(urethane-urea) elastomer.

[0116] Example 4: Preparation of thermoplastic poly(urethane-urea) using EDA and ADH as mixed chain extenders

[0117] Add 2.63 g of HMDI, 10 g of PTMEG2000, 140 μL of DBTDL and 15 g of anhydrous DMF into a 100 mL round-bottom flask. Under magnetic stirring, heat it in an 80 °C oil bath for 3 h. Dissolve 0.50 g of EDA and 0.44 g of ADH in 30 g of anhydrous DMF. After the reaction is completed and cooled to 45 °C, add the mixed DMF solution of EDA and ADH, and react for 3 h under magnetic stirring. Pour it into a glass dish for defoaming. After defoaming until no more bubbles are generated, place it in an oven at 90 °C for curing for 12 h, and demold to obtain the target thermoplastic poly(urethane-urea) elastomer.

[0118] Example 5: Preparation of thermoplastic poly(urethane-urea) using PPDA and ADH as mixed chain extenders

[0119] Add 2.63 g of HMDI, 10 g of PTMEG2000, 140 μL of DBTDL and 15 g of anhydrous DMF into a 100 mL round-bottom flask. Under magnetic stirring, heat it in an 80 °C oil bath for 3 h. Dissolve 0.27 g of PPDA and 0.44 g of ADH in 30 g of anhydrous DMF. After the reaction is completed and cooled to 45 °C, add the mixed DMF solution of PPDA and ADH, and react for 3 h under magnetic stirring. Pour it into a glass dish for defoaming. After defoaming until no more bubbles are generated, place it in an oven at 90 °C for curing for 12 h, and demold to obtain the target thermoplastic poly(urethane-urea) elastomer.

[0120] Example 6: Preparation of thermoplastic poly(urethane-urea) with ODA and ADH as mixed chain extenders

[0121] Add 2.63 g of HMDI, 10 g of PTMEG2000, 140 μL of DBTDL and 15 g of anhydrous DMF into a 100 mL round-bottom flask. Under magnetic stirring, heat it in an 80 °C oil bath for 3 h. Dissolve 0.5 g of ODA and 0.44 g of ADH in 30 g of anhydrous DMF. After the reaction is completed and cooled to 45 °C, add the mixed DMF solution of ODA and ADH, and react for 3 h under magnetic stirring. Pour it into a glass dish for defoaming. After defoaming until no more bubbles are generated, place it in an oven at 90 °C for curing for 12 h, and demold to obtain the target thermoplastic poly(urethane-urea) elastomer.

[0122] Example 7: Preparation of thermoplastic poly(urethane-urea) with IPDH and ADH as mixed chain extenders

[0123] Add 2.63 g of HMDI, 10 g of PTMEG2000, 140 μL of DBTDL and 15 g of anhydrous DMF into a 100 mL round-bottom flask. Under magnetic stirring, heat it in an 80 °C oil bath for 3 h. Dissolve 0.49 g of IPDH and 0.44 g of ADH in 30 g of anhydrous DMF. After the reaction is completed and cooled to 45 °C, add the mixed DMF solution of IPDH and ADH, and react for 3 h under magnetic stirring. Pour it into a glass dish for defoaming. After defoaming until no more bubbles are generated, place it in an oven at 90 °C for curing for 12 h, and demold to obtain the target thermoplastic poly(urethane-urea) elastomer.

[0124] Test Example

[0125] Test the properties of the polymers prepared in Comparative Example 1, Comparative Example 8 and Example 1, and the results are as Figure 2-3 shown.

[0126] Among them: Figure 2 is the comparison of the mechanical properties of the polymers of the single rigid chain extender, single flexible chain extender, and rigid-flexible mixed chain extender prepared in Comparative Example 1, Comparative Example 8 and Example 1.

[0127] Figure 3 Figures a - c are schematic diagrams of cyclic tensile tests at variable strain for polymers prepared with a single rigid chain extender, a single flexible chain extender, and a rigid - flexible mixed chain extender in Comparative Example 1, Comparative Example 8, and Example 1 respectively. 100% represents a maximum strain of 100%, 200% represents a maximum strain of 200%, 300% represents a maximum strain of 300%, 400% represents a maximum strain of 400%, 500% represents a maximum strain of 500%, 600% represents a maximum strain of 600%, 800% represents a maximum strain of 800%, 1000% represents a maximum strain of 1000%, 1200% represents a maximum strain of 1200%, 1400% represents a maximum strain of 1400%, and 1800% represents a maximum strain of 1800%. Figure 3 Figure d is a numerical summary of the integral area (dissipated energy) of each hysteresis loop in Figures a - c.

[0128] Figure 4 It is a mechanical comparison diagram of the repair ability of the polymer containing the mixed chain extender prepared in Example 1.

[0129] From Figure 2-3 it can be seen that the polymer prepared with the rigid - flexible mixed chain extender exhibits significantly higher fracture strength, elongation at break, and toughness than the single chain extender. From the dissipated energy data obtained from the variable - strain tensile test, since the mixed chain extender hybridizes the rigid supramolecular interaction and the flexible supramolecular interaction, when the supramolecular interaction bears external stress, it is more likely to dissociate and recombine, better playing the role of sacrificial bonds, thereby dissipating the externally applied energy and achieving toughening of the material. While the single rigid chain extender will cause excessive stacking of rigid supramolecular interactions inside the material, and the single flexible chain extender will cause excessive entanglement of flexible supramolecular interactions inside the material. The excessive supramolecular interactions are not easily dissociated and recombined, making it difficult to dissipate energy, so it is more prone to fracture and has low toughness.

[0130] 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, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, 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 method for toughening thermoplastic poly(urethane-urea) by the synergistic effect of rigid-flexible supramolecular segments, comprising: (1) Reacting a diisocyanate and an oligomeric polyol under the action of a catalyst to form a polyurethane prepolymer; The diisocyanate is selected from one or more of 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate; The oligomeric diol is selected from one or more of polytetrahydrofuran, polycaprolactone diol, polyethylene glycol, polypropylene glycol; (2) Mixing an organic solution of a mixed chain extender with the thermoplastic polyurethane prepolymer, heating and reacting, and drying the solvent to obtain a thermoplastic poly(urethane-urea) elastomer; The mixed chain extender is a mixed chain extender containing both a rigid chain extender and a flexible chain extender; the rigid chain extender is selected from one or more of 4,4'-diaminobenzanilide, N1,N4-bis(4-aminophenyl) terephthalamide, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylmethane, p-phenylenediamine, 4,4'-diaminodiphenyl ether; the flexible chain extender is selected from one or more of 1,4-butanediol, 1,4-butanediamine, adipic dihydrazide.

2. The method for toughening thermoplastic poly(urethane-urea) by synergistically using rigid-flexible supramolecular segments according to claim 1, wherein The mixed chain extender accounts for 2-7% of the mass of the raw materials of thermoplastic poly(urethane-urea).

3. The method for toughening thermoplastic poly(urethane-urea) by synergistic action of rigid-flexible supramolecular segments according to claim 1, characterized in that, The solvent of the organic solution of the mixed chain extender is an organic solvent, selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone.

4. The method for toughening thermoplastic poly(urethane-urea) by synergistically using rigid-flexible supramolecular segments according to claim 1, wherein The heating temperature for the reaction of the chain extender and the prepolymer is 30-60 °C, and the reaction time is 1.5-8 h.

5. A rigid-flexible supramolecular synergistically toughened thermoplastic poly(urethane-urea) elastomer prepared by the method for toughening thermoplastic poly(urethane-urea) by the synergistic effect of the rigid-flexible supramolecular segments as claimed in claim 1.

6. An application of the rigid-flexible supramolecular synergistically toughened thermoplastic poly(urethane-urea) elastomer as claimed in claim 5 in the fields of buffer and shock-absorbing materials, anti-impact coating protection materials, military and police sports products.

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