Room-temperature self-repairing tough polyurethane elastomer as well as preparation method and application thereof
By introducing dynamic covalent bond pyrrolidinurea bonds and copper ion coordination interactions in polyurethane elastomers, combined with hydrogen bond interactions, the problems of flexible materials in low modulus, toughness and room temperature self-healing properties are solved, and the balance of efficient room temperature self-healing performance and strong toughness mechanical properties are achieved.
Patent Information
- Application Number
- CN202510318907.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-18
- Publication Date
- 2025-05-23
AI Technical Summary
The prior art is difficult to achieve the low modulus, toughness and room temperature self-healing properties of flexible materials simultaneously, and it is difficult to balance the mechanical properties and self-healing properties of existing room temperature self-healing materials.
By introducing dynamic covalent bonds pyrrolidinurea bonds on the molecular chain of polyurethane elastomer and coordinating with copper ions, it promotes the dissociation and recombination of dynamic covalent bonds at room temperature, and combines hydrogen bond interactions to improve the mechanical properties and self-healing properties of the material.
The strength and toughness mechanical properties of polyurethane elastomers and excellent room temperature self-repair function are achieved, with tensile strength up to 18.2MPa, elongation of break as high as 4000%, and the fracture toughness repair rate reaches 90.6% within 24 hours of room temperature, exceeding the room temperature self-repair materials reported in existing literature.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the field of self-repairing materials, and in particular relates to a room temperature self-repairing strong and tough polyurethane elastomer and a preparation method and application thereof. Background Art
[0002] Flexible materials show broad application prospects in the fields of electronic skin, bionic robots and human-computer interaction. A major challenge currently faced by flexible materials is to achieve the softness, toughness and self-healing properties of the materials. In bionic robots, materials usually require a low elastic modulus to simulate the tactile properties of human skin. At the same time, high toughness is essential to prevent material damage or destruction during application, thereby reducing material costs and extending service life. In addition, after being damaged, self-healing materials can be restored to their original state under external stimuli such as light, heat or electricity, which can greatly improve the service life of the materials. Therefore, giving materials bionic self-healing functions has received increasing attention. It is worth noting that sometimes the tiny damage to the material is difficult to detect or it is difficult to achieve optimal healing conditions when the material is integrated into a microelectronic system. Therefore, it is very important to develop materials that can spontaneously self-heal at room temperature.
[0003] However, achieving low modulus, strong toughness and self-healing properties at the same time is a daunting challenge. Fundamentally, low modulus and room temperature self-healing require polymer molecular structures with low rigidity and weak intermolecular interactions, and damage repair is achieved through rearrangement of molecular chains or segments at room temperature. In contrast, high toughness usually relies on strong intermolecular interactions, which require a lot of energy dissipation to break during material deformation. Therefore, manufacturing flexible materials that combine low modulus, high toughness and room temperature self-healing capabilities is both a key requirement for practical applications and a major challenge in the field of materials science.
[0004] At present, the materials with room temperature self-healing function reported in the research are mainly realized by two mechanisms. The first strategy utilizes dynamic non-covalent interactions, such as hydrogen bonds, metal ion coordination and host-guest interactions. Although the materials manufactured by this method exhibit good self-healing properties, their mechanical properties are generally affected. Although increasing the density of non-covalent bonds can improve mechanical properties, this modification usually affects the room temperature self-healing efficiency. Therefore, it is difficult to achieve a balance between mechanical properties and self-healing properties. Another method is to use dynamic covalent chemistry, such as aromatic disulfide bonds, borate bonds, Schiff bases, etc., which can undergo dynamic reversible dissociation and recombination at room temperature. The method of introducing dynamic covalent bonds can usually achieve good mechanical properties and self-healing properties of the material. However, the types of covalent bonds that can be dynamically exchanged at room temperature are still very limited. Therefore, it is very important to develop new types of dynamic reversible covalent bonds to achieve material toughness and room temperature self-healing functions for the preparation and application of new flexible materials. Summary of the invention
[0005] The purpose of the present invention is to provide a room temperature self-repairing strong and tough polyurethane elastomer and a preparation method thereof.
[0006] The room temperature self-repairing strong polyurethane elastomer provided by the present invention has strong mechanical properties, including a tensile strength of up to 18.2MPa, an elongation at break of up to 4000%, and a fracture toughness of 232.2MJ m -3 , and has very excellent room temperature self-repairing function, with a fracture toughness repair rate of 90.6% within 24 hours at room temperature. The mechanical properties and self-repairing properties exceed the room temperature self-repairing materials reported in the literature. In the present invention, a dynamic covalent pyrrolidine urea bond is introduced into the polyurethane elastomer molecular chain, and the coordination complex formed after coordination with copper ions can promote the dissociation and recombination of the dynamic covalent bond at room temperature, thereby realizing the self-repairing property of the elastomer at room temperature. At the same time, a strong hydrogen bond interaction is formed between the urea and carbamate groups in the polymer network, which, combined with the ion coordination, gives the elastomer excellent mechanical properties.
[0007] The present invention provides a method for preparing a room temperature self-repairing tough polyurethane elastomer, comprising the following steps:
[0008] (1) Preparation of linear polyurethane containing pyrrolidine urea bonds;
[0009] (2) mixing the linear polyurethane containing pyrrolidine urea bonds with a copper ion solution to prepare a copper ion coordinated polyurethane solution;
[0010] (3) Pour the copper ion coordinated polyurethane solution into a mold and dry the solvent to obtain a polyurethane elastomer.
[0011] In step (1) of the above method, the linear polyurethane containing pyrrolidine urea bonds is obtained by reacting diisocyanate with pyrrolidone and hydroxyl-terminated polyol.
[0012] Wherein, the diisocyanate is selected from at least one of toluene diisocyanate, hydrogenated phenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate and phenylmethane diisocyanate.
[0013] The pyrrolidone is selected from at least one of 3-hydroxypyrrolidine, pyrrolidine-2-methanol and L-hydroxyproline.
[0014] The hydroxyl-terminated polyol is selected from at least one of polyether polyol, polyester polyol and polyolefin polyol.
[0015] According to an embodiment of the present invention, the polyether polyol is selected from at least one of polyethylene glycol, polypropylene glycol and polytetramethylene glycol.
[0016] According to an embodiment of the present invention, the polyester polyol is at least one selected from polycaprolactone diol, polylactic acid diol, polyethylene adipate diol, and polybutylene adipate diol.
[0017] According to an embodiment of the present invention, the polyolefin polyol is selected from polybutadiene diol.
[0018] According to an embodiment of the present invention, the number average molecular weight of the hydroxyl-terminated polyol is 1000 to 10000 g / mol.
[0019] The linear polyurethane containing pyrrolidone urea bonds can be prepared specifically according to a method comprising the following steps: in the presence of a catalyst, diisocyanate is mixed with pyrrolidone, a hydroxyl-terminated polyol and an organic solvent to undergo a stepwise addition polymerization reaction until the isocyanate group completely disappears, thereby obtaining a linear polyurethane solution.
[0020] According to an embodiment of the present invention, the catalyst is a tertiary amine (such as triethylenediamine, bis(dimethylaminoethyl)ether) or an organic metal catalyst (such as stannous octoate, n-butyltin laurate);
[0021] According to an embodiment of the present invention, the organic solvent is selected from at least one of acetone, tetrahydrofuran, dimethyl sulfoxide, and dimethylformamide;
[0022] According to an embodiment of the present invention, the dosage of the catalyst is 200-600 ppm; the reaction temperature of the polymerization reaction is 50-100° C., and the reaction time is 1-12 hours;
[0023] According to an embodiment of the present invention, the molar ratio of the diisocyanate, pyrrolidone, and hydroxyl-terminated polyol is 1:(0.2-0.7):(0.3-0.8).
[0024] In step 2) of the above method, the copper ion solution can be selected from a copper salt solution, the copper salt can be selected from copper chloride, copper sulfate, copper nitrate, etc., and the molar ratio of the copper ion to the pyrrolidone used in preparing the linear polyurethane containing pyrrolidine urea bonds is 1:10 to 1:30; the mixing process is 40 to 80° C. and mechanically stirred for 1 to 2 hours.
[0025] In step 3) of the above method, the drying conditions are: drying at 60-120° C. for 12-48 hours.
[0026] In step 3) of the above method, the mold may be a polytetrafluoroethylene mold.
[0027] The room temperature self-healing strong polyurethane elastomer prepared by the above method also falls within the protection scope of the present invention.
[0028] Furthermore, the room temperature self-healing strong polyurethane elastomer can be a gray-brown translucent film.
[0029] The present invention also provides the use of the room temperature self-healing strong and tough polyurethane elastomer in the preparation of at least one of the following materials: a flexible conductive material, a flexible sensing material, and an electrolyte.
[0030] Compared with the prior art, the present invention has the following advantages:
[0031] (1) The polyurethane elastomer prepared by the present invention has both strong mechanical properties and excellent room temperature self-healing properties. Since the pyrrolidine urea bond coordinated by copper ions can achieve dynamic dissociation and recombination at room temperature, the elastomer has very excellent room temperature self-healing properties. At the same time, due to the ion coordination interaction and the strong hydrogen bond interaction between molecular chains, the polyurethane elastomer has very strong mechanical properties, and its fracture toughness is the highest among the room temperature self-healing elastomers reported in the literature.
[0032] (2) Polyurethane elastomers have low raw material costs and a simple synthesis process, making them suitable for large-scale production. They have broad application prospects in the fields of flexible conductive materials, flexible sensing materials, electrolytes, etc. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Figure 1 Shown is the H-NMR spectrum of the linear polyurethane prepared in Example 1 of the present invention.
[0034] Figure 2 What is shown is the mechanical properties of the polyurethane elastomer prepared in Example 1 of the present invention.
[0035] Figure 3 What is shown is the surface scratch repair performance of the polyurethane elastomer prepared in Example 1 of the present invention.
[0036] Figure 4 Shown are the stress relaxation test results of the polyurethane elastomer prepared in Example 1 of the present invention.
[0037] Figure 5 What is shown is the self-healing efficiency of the polyurethane elastomer prepared in Example 1 of the present invention.
[0038] Figure 6 The surface scratch repairing condition of the polyurethane elastomer prepared in Example 2 of the present invention is shown.
[0039] Figure 7 Shown are the tensile curves of the polyurethane elastomer prepared in Example 2 of the present invention before and after repair.
[0040] Figure 8 What is shown is the self-healing condition of the polyurethane elastomer prepared in Comparative Example 1 of the present invention. DETAILED DESCRIPTION
[0041] The present invention is further described in detail below in conjunction with specific embodiments, and the examples provided are only for illustrating the present invention, rather than for limiting the scope of the present invention. The examples provided below can be used as a guide for further improvements by those of ordinary skill in the art, and do not constitute a limitation of the present invention in any way.
[0042] The experimental methods in the following examples, unless otherwise specified, are all conventional methods, and are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial channels.
[0043] Example 1. Preparation of polyurethane elastomer containing dynamic pyrrolidine urea
[0044] In a 250 mL round-bottom flask equipped with a mechanical stirrer, a nitrogen inlet tube, a thermometer and a dropping funnel, 11.1 g (50 mmol) of isophorone diisocyanate (IPDI) was added, and then 2.18 g (25 mmol) of 3-pyrrolidone, 50.0 g (25 mmol) of polytetrahydrofuran diol (molecular weight 2000), and dimethylformamide (64 mL) were reacted at 70° C. for 2 hours, and then 0.04 g of n-butyltin laurate as a catalyst was added to the system and the temperature of the reaction system in the flask was maintained at 70° C. The reaction was continued, and the degree of reaction was monitored by Fourier infrared. The reaction was stopped when the characteristic infrared absorption peak of the isocyanate group completely disappeared, and a linear polyurethane solution containing pyrrolidine urea bonds was obtained.
[0045] CuCl 2 -2H 2 O (0.21 g, 1.25 mmol) was dissolved in 20 ml of DMF. Then, the solution was poured into the above polyurethane solution and stirred at 60° C. for 2 hours under nitrogen atmosphere to obtain a polyurethane solution coordinated with copper ions.
[0046] Finally, the copper ion coordinated polyurethane solution was cast into a polytetrafluoroethylene mold, and the solvent was dried in an oven at 100° C. for 24 hours to obtain a gray-brown translucent film.
[0047] Example 2: Preparation of polyurethane elastomer containing dynamic pyrrolidine urea
[0048] In a 250mL round-bottom flask equipped with a mechanical stirrer, a nitrogen inlet tube, a thermometer and a dropping funnel, 8.4g (50mmol) of hexamethylene diisocyanate (HDI) was added, and then 1.515g (15mmol) of pyrrolidine-2-methanol, 70.0g (35mmol) of polyethylene glycol (molecular weight 2000), and tetrahydrofuran (64mL) were reacted at 60°C for 2 hours, and then 0.06g of n-butyltin laurate as a catalyst was added to the system and the temperature of the reaction system in the flask was maintained at 60°C. The reaction was continued and the degree of reaction was monitored by Fourier infrared. The reaction was stopped when the characteristic infrared absorption peak of the isocyanate group completely disappeared, and a linear polyurethane solution containing pyrrolidine urea bonds was obtained.
[0049] CuCl 2 -2H 2 O (0.25 g, 1.5 mmol) was dissolved in 20 ml of DMF. Then, the solution was poured into the above linear polyurethane solution and stirred at 40° C. for 1 hour under nitrogen atmosphere to obtain a copper ion coordinated polyurethane solution.
[0050] Finally, the copper ion coordinated polyurethane solution was cast into a polytetrafluoroethylene mold and dried in an oven at 60° C. for 48 hours to obtain a gray-brown translucent film.
[0051] Comparative Example 1: Preparation of polyurethane elastomer without dynamic pyrrolidine urea covalent bonds
[0052] In a 250mL round-bottom flask equipped with a mechanical stirrer, a nitrogen inlet tube, a thermometer and a dropping funnel, 11.1g (50mmol) of isophorone diisocyanate (IPDI) was added, and then 2.25g (25mmol) of 1,4-butanediol, 50.0g (25mmol) of polytetrahydrofuran diol (molecular weight 2000), and dimethylformamide (64mL) were reacted at 60°C for 2 hours, and then 0.04g of n-butyltin laurate as a catalyst was added to the system and the temperature of the reaction system in the flask was maintained at 60°C. The reaction was continued, and the degree of reaction was monitored by Fourier infrared. When the characteristic infrared absorption peak of the isocyanate group completely disappeared, the reaction was stopped.
[0053] The polyurethane solution was directly cast into a polytetrafluoroethylene mold, and after the solvent was dried in an oven at 100°C for 24 hours, a colorless and transparent film was obtained.
[0054] Figure 1 The H-NMR spectrum of the linear polyurethane prepared in Example 1 of the present invention is shown. The results show that the linear polyurethane was successfully prepared.
[0055] Figure 2The mechanical properties of the polyurethane elastomer prepared in Example 1 of the present invention are shown. The tensile curve of the elastomer shows that the prepared polyurethane elastomer has strong mechanical properties, wherein the tensile strength is as high as 18.2 MPa, the elongation at break is as high as 4000%, and the fracture toughness is 232.2 MJ m -3 .
[0056] Figure 3 The surface scratch repair performance of the polyurethane elastomer prepared in Example 1 of the present invention is shown. The optical electron microscope shows that the scratches on the surface of the sample disappear within 5 minutes at room temperature, indicating that the elastomer has very excellent surface scratch self-repair performance.
[0057] Figure 4 The stress relaxation test results of the polyurethane elastomer prepared in Example 1 of the present invention are shown. The results show that the stress of the polyurethane elastomer containing pyrrolidine urea decreases rapidly at room temperature, but the stress of the elastomer does not drop to 0 due to the physical crosslinking formed by the coordination interaction of copper ions.
[0058] Figure 5 The self-repairing efficiency of the polyurethane elastomer prepared in Example 1 of the present invention is shown. The photo shows that the cut strips have good tensile properties after being reconnected and placed at room temperature for one hour. The tensile curve shows that it has very excellent room temperature self-repairing function, and the fracture toughness repair rate within 24 hours at room temperature is as high as 90.6%.
[0059] Figure 6 The surface scratch repair of the polyurethane elastomer prepared in Example 2 of the present invention is shown. The optical electron microscope shows that the scratches on the surface of the sample disappear within 10 minutes at room temperature, indicating that the elastomer has very excellent surface scratch self-repairing performance.
[0060] Figure 7 The tensile curves of the polyurethane elastomer prepared in Example 2 of the present invention before and after repair are shown. The tensile curves show that the fracture toughness repair rate of the broken specimen reaches 92.9% after 24 hours of repair.
[0061] Figure 8 The self-repairing condition of the polyurethane elastomer prepared in Comparative Example 1 of the present invention is shown. The tensile curve shows that after the polyurethane elastomer without pyrrolidine urea bonds is cut, reconnected and repaired for 24 hours, the repaired elastomer has a certain stretchability due to the effect of hydrogen bonds between polymer molecules, but the elongation at break is very low, indicating that the self-repairing efficiency of the polyurethane elastomer without dynamic bonds is very low and basically has no self-repairing performance.
[0062] The present invention has been described in detail above. It will be apparent to those skilled in the art that the present invention may be implemented in a wide range under equivalent parameters, concentrations and conditions without departing from the spirit and scope of the present invention and without the need for unnecessary experimentation. Although the present invention provides specific embodiments, it should be understood that further improvements may be made to the present invention. In short, according to the principles of the present invention, this application intends to include any changes, uses or improvements to the present invention, including changes made by conventional techniques known in the art that depart from the scope disclosed in this application. Applications of some of the basic features may be made within the scope of the following appended claims.
Claims
1. A method for preparing a room temperature self-repairing tough polyurethane elastomer, comprising the following steps: (1) Preparation of linear polyurethane containing pyrrolidine urea bonds; (2) mixing the linear polyurethane containing pyrrolidine urea bonds with a copper ion solution to prepare a copper ion coordinated polyurethane solution; (3) Pour the copper ion coordinated polyurethane solution into a mold and dry the solvent to obtain a polyurethane elastomer.
2. The preparation method according to claim 1, characterized in that: In the step (1), the linear polyurethane containing pyrrolidine urea bonds is obtained by reacting diisocyanate with pyrrolidone and hydroxyl-terminated polyol.
3. The preparation method according to claim 2, characterized in that: The diisocyanate is selected from at least one of toluene diisocyanate, hydrogenated phenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate and phenylmethane diisocyanate; And / or, the pyrrolidone is selected from at least one of 3-hydroxypyrrolidine, pyrrolidine-2-methanol, and L-hydroxyproline; And / or, the hydroxyl-terminated polyol is selected from at least one of polyether polyol, polyester polyol and polyolefin polyol.
4. The preparation method according to claim 3, characterized in that: The polyether polyol is selected from at least one of polyethylene glycol, polypropylene glycol and polytetrahydrofuran diol; And / or, the polyester polyol is at least one selected from polycaprolactone diol, polylactic acid diol, polyethylene adipate diol, and polybutylene adipate diol; and / or, the polyolefin polyol is selected from polybutadiene diol; And / or, the number average molecular weight of the hydroxyl-terminated polyol is 1000 to 10000 g / mol.
5. The preparation method according to any one of claims 1 to 4, characterized in that: The linear polyurethane containing pyrrolidinourea bonds is prepared specifically according to a method comprising the following steps: in the presence of a catalyst, diisocyanate is mixed with pyrrolidol, a hydroxyl-terminated polyether or polyester polyol and an organic solvent, and a stepwise addition polymerization reaction occurs until the isocyanate group completely disappears, thereby obtaining a linear polyurethane solution containing pyrrolidinourea bonds.
6. The preparation method according to claim 5, characterized in that: The catalyst is a tertiary amine or an organic metal catalyst; further, the tertiary amine is selected from at least one of the following: triethylenediamine, bis(dimethylaminoethyl) ether, and the organic metal catalyst is selected from at least one of the following: stannous octoate, n-butyltin laurate; And / or, the organic solvent is selected from at least one of acetone, tetrahydrofuran, dimethyl sulfoxide and dimethylformamide; And / or, the dosage of the catalyst is 200-600 ppm; the reaction temperature of the polymerization reaction is 50-100° C., and the reaction time is 1-12 hours; And / or, the molar ratio of the diisocyanate, pyrrolidone and hydroxyl-terminated polyol is 1:(0.2-0.7):(0.3-0.8).
7. The preparation method according to any one of claims 1 to 6, characterized in that: In the step (2), the copper ion solution is selected from a copper salt solution; the molar ratio of the copper ions in the copper ion solution to the pyrrolidone used in the preparation of the linear polyurethane containing pyrrolidone urea bonds is 1:10 to 1:30; And / or, the mixing process is performed at 40-80° C. with mechanical stirring for 1-2 hours.
8. The preparation method according to any one of claims 1 to 7, characterized in that: In the step (3), the drying conditions are: drying at 60-120° C. for 12-48 hours.
9. A room temperature self-healing tough polyurethane elastomer prepared according to the method according to any one of claims 1 to 8.
10. Use of the room temperature self-healing strong and tough polyurethane elastomer according to claim 9 in the preparation of at least one of the following materials: flexible conductive materials, flexible sensing materials, and electrolytes.