Super-soft ionic liquid conductive self-healing polyurethane elastomer and preparation method thereof

Abstract

The present application relates to a kind of super-soft ionic liquid conductive self-repairing polyurethane elastomer and its preparation method, belong to medical care field, it can conduct electricity, good flexibility, can be self-repaired at room temperature Material.The material Young's modulus is low, with good elasticity and flexibility.The material can realize efficient self-repairing under mild conditions at room temperature, and the tensile strength can recover 60% of initial value.In addition, the conductive performance of elastomer material is excellent, under large strain and small strain, electrical signal can be detected, and it can be applied to flexible electrical sensor device.The prepolymer and polyether 330N form irreversible covalent crosslinking point, to improve the mechanical properties of polyurethane elastomer;And this crosslinking structure can improve its structural stability, so as to ensure the mechanical property stability of the ionic liquid surface modified conductive self-repairing polyurethane.

Description

Technical Field

[0001] The present invention relates to an ultra-soft ionic liquid conductive self-repairing polyurethane elastomer and a preparation method thereof, belonging to the technical field of medical care. The ultra-soft ionic liquid conductive self-repairing polyurethane elastomer is conductive, has a low Young's modulus, good elasticity and flexibility, and can self-repair the material at room temperature. Background Art

[0002] Stretchable electronic materials and devices have attracted widespread attention due to their important applications in many fields, particularly healthcare. For example, stretchable strain sensors can be used to monitor body movements, and stretchable conductors can be used as epidermal electrodes for biopotential detection. Stretchable strain sensors are typically made of elastomeric composites and nanoconductive fillers, such as carbon nanotubes, graphene, or metallic nanomaterials, which are often used as conductive fillers in stretchable composites. Conventional conductors have very limited stretchability and are much stiffer than soft human skin.

[0003] However, traditional materials use irreversible covalent bonds, which, once broken, are irreversible and difficult to self-repair. Self-healing materials, on the other hand, can spontaneously repair physical damage and restore mechanical properties to extend their service life. Most healing materials are not conductive, and the addition of conductive fillers can cause degradation of the material's mechanical properties. Therefore, developing a polyurethane that is simultaneously conductive, elastic, and flexible, and self-healable at room temperature is of great significance for improving the material's mechanical properties and application range. Summary of the Invention

[0004] The technical solution of this invention is to overcome the shortcomings of the existing technology and propose an ultra-flexible ionic liquid conductive self-healing polyurethane elastomer and its preparation method. Polyurethane and polyether 330N form irreversible covalent chemical crosslinks, improving the overall performance of the polyurethane elastomer. Furthermore, through surface modification and the addition of ionic liquid, the structural and mechanical stability of the ultra-flexible ionic liquid conductive self-healing polyurethane elastomer can be ensured. This material has excellent electrical conductivity and can detect electrical signals under both large and small strains, making it suitable for flexible electrical sensor devices.

[0005] The objectives of the present invention are achieved through the following technical solutions.

[0006] A super-soft ionic liquid conductive self-healing polyurethane elastomer, wherein the raw materials of the super-soft ionic liquid conductive self-healing polyurethane elastomer include component A, component B and component C, and also include isopropyl alcohol, a toluene solution of di-n-butylamine, a bromocresol blue indicator, 0.1 mol / L dilute hydrochloric acid, and an organic solvent;

[0007] Taking the mass of component A as 100%, the mass percentages of the components in component A are as follows:

[0008] Hexamethylene diisocyanate (HDI) 37%~39%;

[0009] Polybutylene glycol (PTMG) 61%~63%;

[0010] Taking the mass of component B as 100%, the mass percentages of the components in component B are as follows:

[0011] Polybutylene glycol (PTMG) 87.6%~91.6%;

[0012] Polyether 330N polyol (330N) 6.7% to 10.7%;

[0013] 4,4'-dihydroxydiphenyl disulfide 0.7%~2.7%;

[0014] Taking the mass of the C component as 100%, the mass percentages of the components in the C component are as follows:

[0015] Choline chloride 42%~44%;

[0016] Glycerol 56%~58%;

[0017] The organic solvent is N,N-dimethylformamide;

[0018] The molecular weight of the polybutylene glycol is 1760-2080;

[0019] The molecular weight of the polyether 330N polyol is 4600-4800;

[0020] The polybutylene glycol, hexamethylene diisocyanate and polyether 330N polyol need to be dehydrated.

[0021] A method for preparing an ultra-soft ionic liquid conductive self-repairing polyurethane elastomer, the method comprising the following steps:

[0022] In the first step, hexamethylene diisocyanate (HDI) and polytetramethylene glycol (PTMG) in component A are dehydrated and then mixed under nitrogen atmosphere. The mixture is then heated to 80-85°C and stirred for 4-5 hours at a stirring speed of 180-220 r / min to obtain a polyurethane prepolymer.

[0023] In the second step, a portion of the polyurethane prepolymer obtained in the first step and isopropyl alcohol are mixed in a water bath at 45-55° C., with a mixing volume of L and a mixing time of 10-15 minutes. A toluene solution of di-n-butylamine and a bromocresol blue indicator are then added, followed by titration with 0.1 mol / L dilute hydrochloric acid until the solution no longer changes color within 30 seconds. The titration is then terminated, and the isocyanate content a in the polyurethane prepolymer is calculated after the titration is completed.

[0024] The ratio of the polyurethane prepolymer to isopropyl alcohol is 3-4 g: 500 mL;

[0025] The volume ratio of the mixed volume L of the polyurethane prepolymer and isopropyl alcohol to the toluene solution of di-n-butylamine is 2:1;

[0026] The ratio of the volume L of the polyurethane prepolymer and isopropyl alcohol after mixing to the bromocresol blue indicator is 1000 mL:1 g;

[0027] The ratio of the mass (g) of di-n-butylamine to the volume (ml) of the solvent toluene is 129g:166ml;

[0028] In the third step, the polytetramethylene glycol (PTMG) and polyether 330N polyol (330N) in component B are dehydrated;

[0029] Step 4: dissolving the 4,4'-dihydroxydiphenyl disulfide in component B in an organic solvent, and then mixing it with a portion of the polyurethane prepolymer obtained in the first step, the dehydrated polytetramethylene glycol (PTMG) in component B, and polyether 330N polyol (330N), at a mixing temperature of 30-50°C;

[0030] Step 5: Stir the mixed material from step 4 at a speed of 1900-2100 r / min for 10-15 seconds, pour it into a polytetrafluoroethylene mold, cure it at 75-85°C for 48 hours, and then dry it in a vacuum oven at 75-85°C for 48 hours to remove the organic solvent, thereby obtaining a polyurethane elastomer.

[0031] Step 6: Mix the choline chloride and glycerol in material C, heat to 95-105°C, and stir to dissolve for 2-3 hours to obtain an ionic liquid;

[0032] In the seventh step, the polyurethane elastomer prepared in the fifth step is soaked in an organic solvent for 10-20 minutes, and then the ionic liquid is evenly coated on the surface of the self-healing polyurethane substrate, and then dried in a forced air oven at 80°C for 6 hours to obtain an ultra-soft ionic liquid conductive self-healing polyurethane elastomer.

[0033] In the fourth step, the ratio of 4,4'-dihydroxydiphenyl disulfide, polyurethane prepolymer, polytetramethylene glycol (PTMG), and polyether 330N polyol satisfies the following conditions:

[0034] (m1×a%) / 42=R×((m2 / N1)×2+(m3 / N2)×3+(m4 / N3)×2)

[0035] Wherein, m1 is the mass of polyurethane prepolymer, m2 is the mass of polytetramethylene glycol (PTMG), m3 is the mass of polyether 330N polyol, and m4 is the mass of 4,4'-dihydroxydiphenyl disulfide;

[0036] N1, is the molecular weight of polytetramethylene glycol (PTMG);

[0037] N2 is the molecular weight of polyether 330N polyol;

[0038] N3 is the molecular weight of 4,4'-dihydroxydiphenyl disulfide;

[0039] The value of the isocyanate group in the polyurethane prepolymer is defined as R1, and the sum of the hydroxyl groups in 4,4'-dihydroxydiphenyl disulfide, polytetramethylene glycol (PTMG) and polyether 330N polyol is R2, then R=R1 / R2, R =1.04~1.06.

[0040] Beneficial effects

[0041] (1) The present invention provides an ultra-soft ionic liquid conductive self-healing polyurethane elastomer and a preparation method thereof, wherein the ultra-soft ionic liquid conductive self-healing polyurethane elastomer is a new type of high-performance conductive polyurethane elastomer. The material has a low Young's modulus and good elasticity and flexibility. The material can achieve efficient self-healing under mild conditions at room temperature, and its tensile strength can recover 60% of the initial value. In addition, the elastomer material has excellent electrical conductivity, and electrical signals can be detected under large and small strains, and can be applied to flexible electrical sensor devices. The prepolymer and polyether 330N form irreversible covalent chemical crosslinking points, thereby improving the mechanical properties of the polyurethane elastomer; and this crosslinking structure can improve its structural stability, thereby ensuring the mechanical property stability of the ultra-soft ionic liquid conductive self-healing polyurethane elastomer.

[0042] (2) The present invention provides a method for preparing an ultra-soft ionic liquid conductive self-healing polyurethane elastomer. In the method, both ends of hexamethylene diisocyanate (HDI) in material A contain isocyanate groups, and both ends of polytetramethylene glycol (PTMG) contain hydroxyl groups. After the initial synthesis of the prepolymer, the two can be polymerized with material B at room temperature to produce a polyurethane elastomer, and then the finished product can be obtained by evaporating the solvent. The method has simple steps, and the experimental formula can be changed according to production needs, and can be industrially produced.

[0043] (3) The present invention provides a method for preparing an ultra-soft ionic liquid conductive self-healing polyurethane elastomer. The key to preserving the prepolymer is that the preheating temperature must be maintained at 50°C or below. The prepolymer will self-polymerize at a temperature of 50-70°C. The two ends of the prepolymer are capped with isocyanate (-NCO) groups. At room temperature, it tends to polymerize with the hydroxyl groups in the chain extender, cross-linker and other components in the main raw materials. This polymerization method can promote the forward reaction and accelerate the reaction rate. The produced material has excellent electrical conductivity. Electrical signals can be detected under large and small strains, and can be used in flexible electrical sensor devices.

[0044] (4) The present invention provides a method for preparing an ultra-soft ionic liquid conductive self-healing polyurethane elastomer. The method uses a specific organic solvent (such as N,N-dimethylformamide, dimethyl sulfoxide and chloroform, etc.) for the following purposes: first, to reduce the viscosity of the reaction system; second, to dissolve disulfide compounds and successfully introduce the disulfide compounds into the polyurethane elastomer system.

[0045] (5) The ultra-soft ionic liquid conductive self-healing polyurethane elastomer of the present invention is a new type of high-performance aging-resistant polyurethane elastomer. It forms chemical crosslinks with polyether 330N, which can increase the crosslinking density and improve the mechanical properties of the polyurethane elastomer. Moreover, this crosslinking structure can improve its structural stability, thereby ensuring the mechanical property stability of the ultra-soft ionic liquid conductive self-healing polyurethane elastomer. The present invention also provides a method for preparing an ultra-soft ionic liquid conductive self-healing polyurethane elastomer, which introduces ionic liquid into the polyurethane elastomer system through surface modification to generate an ultra-soft ionic liquid conductive self-healing polyurethane elastomer. This method has simple steps, is relatively safe and environmentally friendly, and the experimental formula can be modified according to production needs, and can be industrialized.

[0046] (6) The present invention relates to a conductive self-healing polyurethane modified with an ionic liquid surface and a preparation method thereof, which belongs to the field of medical care. The material is conductive, flexible, and can self-heal at room temperature. The material has a low Young's modulus and good elasticity and flexibility. The material can achieve efficient self-healing under mild conditions at room temperature, and its tensile strength can recover 60% of the initial value. In addition, the elastomeric material has excellent electrical conductivity, and electrical signals can be detected under large and small strains, and can be applied to flexible electrical sensor devices. The prepolymer and polyether 330N form irreversible covalent chemical crosslinking points, thereby improving the mechanical properties of the polyurethane elastomer; and this crosslinking structure can improve its structural stability, thereby ensuring the mechanical property stability of the conductive self-healing polyurethane modified with an ionic liquid surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is the infrared spectrum of the ultra-soft ionic liquid conductive self-healing polyurethane elastomer;

[0048] Figure 2 This is the result of large strain electrical signal of ultra-soft ionic liquid conductive self-healing polyurethane elastomer;

[0049] Figure 3 This is the small strain electrical signal result diagram of the ultra-soft ionic liquid conductive self-healing polyurethane elastomer;

[0050] Figure 4 This is the room temperature self-healing result of ultra-soft ionic liquid conductive self-healing polyurethane elastomer. DETAILED DESCRIPTION

[0051] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but this does not limit the present invention.

[0052] Example 1

[0053] A super-soft ionic liquid conductive self-healing polyurethane elastomer is composed of three raw material components, A, B, and C. Based on the total mass of each of the raw materials A, B, and C being 100%, the components and their mass fractions in raw material A are as follows: 37%-39% hexamethylene diisocyanate (HDI), 61%-63% polytetramethylene glycol (PTMG); the components and their mass fractions in raw material B are as follows: 87.6%-91.6% polytetramethylene glycol (PTMG), 6.7%-10.7% polyether 330N polyol (330N); and 0.7%-2.7% 4,4'-dihydroxydiphenyl disulfide. The components and their mass fractions in raw material C are as follows: 42%-44% choline chloride, and 56%-58% glycerol. Auxiliary raw materials are an organic solvent (such as N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, etc.) and a toluene solution of the indicator bromocresol blue and di-n-butylamine.

[0054] The molecular weight of the polybutylene glycol is 1760-2080, the molecular weight of the polyether 330N polyol is 4600-4800, and the chain extender is an N,N-dimethylformamide solution of polybutylene glycol and 4,4'-dihydroxydiphenyl disulfide.

[0055] The mass ratio of hexamethylene diisocyanate and polybutylene glycol used in the synthetic polyurethane prepolymer is 3:5.

[0056] The ratio of the mass (g) of the polyurethane prepolymer sample to the volume (mL) of the isopropyl alcohol solvent is (3-4):500; the ratio of the mass (g) of the di-n-butylamine to the volume (mL) of the toluene solvent is 129:166; the volume ratio of the titration sample solution to the volume of the di-n-butylamine toluene solution is 2:1; the ratio of the mass (g) of the indicator bromocresol blue to the volume (mL) of the solution is 1:1000;

[0057] A method for preparing the ultra-soft ionic liquid conductive self-healing polyurethane elastomer described in this embodiment, the specific steps of the method are as follows:

[0058] (1) Add 60 g of hexamethylene diisocyanate and 100 g of polybutylene glycol into a 250 mL three-necked flask, heat it to 80 °C, stir the raw materials at a rate of 200 r / min to mix them evenly, and react for 4 h to obtain a polyurethane prepolymer;

[0059] (2) 0.3921 g of the prepolymer obtained in step (1) was dissolved in 50 mL of a toluene solution of di-n-butylamine and heated at 50°C for 10 min to fully dissolve it. Four drops of bromocresol blue indicator were added, followed by 25 mL of isopropanol to completely dissolve the indicator. Titration with 0.1036 mol / L dilute hydrochloric acid revealed that the isocyanate content in the prepolymer was 17.4%.

[0060] The ratio of the mass (g) of bromocresol blue to the volume (mL) of the solvent sodium hydroxide in the bromocresol blue indicator is 1:1000, and the concentration of the sodium hydroxide is 0.1 mol / L;

[0061] (3) Preheat the dehydrated main raw materials polybutylene glycol and polyether 330N polyol to 70°C, and dissolve 1.9702g of 4,4'-dihydroxydiphenyl disulfide in N,N-dimethylformamide solution in advance;

[0062] (4) 103.339 g of polybutylene glycol, 10.21 g of polyether 330N polyol and an N,N-dimethylformamide solution containing 1.9702 g of 4,4'-dihydroxydiphenyl disulfide in step (3) were added to the container in sequence, and then 33.8945 g of the prepolymer was added and the solution was stirred at a stirring rate of 2000 r / min for 60 s; the solution was poured into a polytetrafluoroethylene container and placed in a 70°C oven for curing for 48 h, and then dried in a vacuum oven at 80°C for 24 h to remove the organic solvent to obtain a polyurethane elastomer.

[0063] (5) 10 g of choline chloride and 13 g of glycerol were stirred at 100 °C and 400 rpm for 2 h to obtain an ionic liquid.

[0064] (6) The prepared polyurethane elastomer was placed in 100 ml of N,N-dimethylformamide and soaked for 20 min. Then, 1 ml of ionic liquid was evenly coated on the surface of the self-healing polyurethane substrate, left to stand for 30 min, and then dried in a forced air oven at 80 °C for 6 h to obtain an ultra-soft ionic liquid conductive self-healing polyurethane elastomer.

[0065] The obtained elastomer was subjected to infrared spectroscopy analysis. Figure 1 As shown by Figure 1 It can be seen that at 3340cm -1 The peak of -NH- stretching vibration appeared at 1720 cm -1 The peak of -CO- stretching vibration appears at 453 cm -1 A peak of -SS- vibration appears.

[0066] The obtained elastomer was tested for large strain electrical signal. The results are as follows: Figure 2When the stretching rate reaches 200%, electrical signals can be detected in the range of 0.015mA~0.018mA, indicating that the elastomer can conduct electricity under large strain.

[0067] The obtained elastomer was subjected to small strain electrical signal test, and the results were as follows: Figure 3 When the stretching rate reaches 120%, electrical signals can be detected in the range of 0.006mA~0.007mA, indicating that the elastomer can conduct electricity under small strain.

[0068] The obtained elastomer was cut and then spliced, and then a tensile test was performed after repairing at room temperature for 1 hour. The results are as follows: Figure 4 As shown in the figure, since the chemical cross-linking points are cut off during the cutting process, the elongation at break is difficult to recover to that of the initial sample, but its tensile strength is basically restored to 55% of the original value.

[0069] Example 2

[0070] A super-soft ionic liquid conductive self-healing polyurethane elastomer is composed of three raw material components, A, B, and C. Based on the total mass of each of the raw materials A, B, and C being 100%, the components and their mass fractions in raw material A are as follows: 37%-39% hexamethylene diisocyanate (HDI), 61%-63% polytetramethylene glycol (PTMG); the components and their mass fractions in raw material B are as follows: 87.6%-91.6% polytetramethylene glycol (PTMG), 6.7%-10.7% polyether 330N polyol (330N); and 0.7%-2.7% 4,4'-dihydroxydiphenyl disulfide. The components and their mass fractions in raw material C are as follows: 42%-44% choline chloride, and 56%-58% glycerol. Auxiliary raw materials are an organic solvent (such as N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, etc.) and a toluene solution of the indicator bromocresol blue and di-n-butylamine.

[0071] The molecular weight of the polybutylene glycol is 1760-2080, the molecular weight of the polyether 330N polyol is 4600-4800, and the chain extender is an N,N-dimethylformamide solution of polybutylene glycol and 4,4'-dihydroxydiphenyl disulfide.

[0072] The mass ratio of hexamethylene diisocyanate and polybutylene glycol used in the synthetic polyurethane prepolymer is 3:5.

[0073] The ratio of the mass (g) of the polyurethane prepolymer sample to the volume (mL) of the isopropyl alcohol solvent is (3-4):500; the ratio of the mass (g) of the di-n-butylamine to the volume (mL) of the toluene solvent is 129:166; the volume ratio of the titration sample solution to the volume of the di-n-butylamine toluene solution is 2:1; the ratio of the mass (g) of the indicator bromocresol blue to the volume (mL) of the solution is 1:1000;

[0074] A preparation method of the super-soft ionic liquid conductive self-repairing polyurethane elastomer described in the embodiment, and the specific steps of the method are as follows:

[0075] (1) 60 g of hexamethylene diisocyanate and 100 g of polybutylene glycol are added to a 250 mL three-necked flask, and the raw materials are stirred at a speed of 200 r / min to mix them uniformly, and the polyurethane prepolymer is obtained after 4 h of reaction;

[0076] (2) 0.3945 g of the prepolymer obtained in step (1) is dissolved in 50 mL of a toluene solution of di-n-butylamine, and heated at 50°C for 10 min to fully dissolve it, 4 drops of bromocresol blue indicator are added dropwise, and then 25 mL of isopropyl alcohol is added to completely dissolve the indicator; 0.1036 mol / L of dilute hydrochloric acid is used for titration, and the isocyanate content in the prepolymer is 16.9%;

[0077] The ratio of the mass (g) of bromocresol blue in the bromocresol blue indicator to the volume (mL) of the solvent sodium hydroxide is 1:1000, and the concentration of the sodium hydroxide is 0.1 mol / L;

[0078] (3) The main raw material polybutylene glycol after dehydration is preheated to 70°C, and 1.9689 g of 4,4'-dihydroxydiphenyl disulfide is dissolved in an N,N-dimethylformamide solution in advance;

[0079] (4) 101.267 g of polybutylene glycol, 9.76 g of polyether 330N polyol, and an N,N-dimethylformamide solution containing 1.9689 g of 4,4'-dihydroxydiphenyl disulfide in step (3) are sequentially added to the container, and then 33.8762 g of the prepolymer is added, and the solution is stirred at a stirring speed of 2000 r / min for 60 s; after pouring into a container made of polytetrafluoroethylene, it is placed in an oven at 70°C for 48 h, and then dried in a vacuum oven at 80°C for 24 h to remove the organic solvent, and a polyurethane elastomer is obtained.

[0080] (5) 10 g of choline chloride and 13 g of glycerol are stirred at 100°C and 400 rpm for 2 h, and then an ionic liquid is obtained.

[0081] (6) The prepared polyurethane elastomer is soaked in 100 ml of N,N-dimethylformamide for 20 min, then 1 ml of ionic liquid is uniformly coated on the surface of the self-repairing polyurethane substrate, and left still for 30 min, and then dried in a 80°C air oven for 6 h to obtain a super-soft ionic liquid conductive self-repairing polyurethane elastomer.

[0082] The obtained elastomer is subjected to infrared spectrum analysis, and the characteristic peaks of the polyurethane elastomer are observed at 3342 cm -1The peak of -NH- stretching vibration appeared at 1722 cm -1 The peak of -CO- stretching vibration appears at 451cm -1 A peak of -SS- vibration appears.

[0083] The obtained elastomer was subjected to a large strain electrical signal test. When the stretching rate reached 220%, electrical signals could be detected in the range of 0.015mA~0.018mA, indicating that the elastomer can conduct electricity under large strain.

[0084] The obtained elastomer was subjected to a small strain electrical signal test. When the stretching rate reached 100%, an electrical signal could be detected in the range of 0.006mA~0.007mA, indicating that the elastomer can conduct electricity under small strain.

[0085] The obtained elastomer was cut and then spliced, and then repaired at room temperature for 1 hour before a tensile test. Since the chemical cross-linking points were cut during the cutting process, the elongation at break was difficult to recover to the same level as the initial sample, but its tensile strength basically recovered to 57% of the original.

[0086] Example 3

[0087] A super-soft ionic liquid conductive self-healing polyurethane elastomer is composed of three raw material components, A, B, and C. Based on the total mass of each of the raw materials A, B, and C being 100%, the components and their mass fractions in raw material A are as follows: 37%-39% hexamethylene diisocyanate (HDI), 61%-63% polytetramethylene glycol (PTMG); the components and their mass fractions in raw material B are as follows: 87.6%-91.6% polytetramethylene glycol (PTMG), 6.7%-10.7% polyether 330N polyol (330N); and 0.7%-2.7% 4,4'-dihydroxydiphenyl disulfide. The components and their mass fractions in raw material C are as follows: 42%-44% choline chloride, and 56%-58% glycerol. Auxiliary raw materials are an organic solvent (such as N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, etc.) and a toluene solution of the indicator bromocresol blue and di-n-butylamine.

[0088] The molecular weight of the polybutylene glycol is 1760-2080, the molecular weight of the polyether 330N polyol is 4600-4800, and the chain extender is an N,N-dimethylformamide solution of polybutylene glycol and 4,4'-dihydroxydiphenyl disulfide.

[0089] The mass ratio of hexamethylene diisocyanate and polybutylene glycol used in the synthetic polyurethane prepolymer is 3:5.

[0090] The ratio of the mass (g) of the polyurethane prepolymer sample to the volume (mL) of the isopropyl alcohol solvent is (3-4):500; the ratio of the mass (g) of the di-n-butylamine to the volume (mL) of the toluene solvent is 129:166; the volume ratio of the titration sample solution to the volume of the di-n-butylamine toluene solution is 2:1; the ratio of the mass (g) of the indicator bromocresol blue to the volume (mL) of the solution is 1:1000;

[0091] A method for preparing the ultra-soft ionic liquid conductive self-healing polyurethane elastomer described in this embodiment, the specific steps of the method are as follows:

[0092] (1) Add 60 g of hexamethylene diisocyanate and 100 g of polybutylene glycol into a 250 mL three-necked flask, heat it to 80 °C, stir the raw materials at a rate of 200 r / min to mix them evenly, and react for 4 h to obtain a polyurethane prepolymer;

[0093] (2) 0.3876 g of the prepolymer obtained in step (1) was dissolved in 50 mL of a toluene solution of di-n-butylamine and heated at 50°C for 10 min to fully dissolve it. Four drops of bromocresol blue indicator were added, followed by 25 mL of isopropanol to completely dissolve the indicator. Titration with 0.1036 mol / L dilute hydrochloric acid revealed that the isocyanate content in the prepolymer was 16.5%.

[0094] The ratio of the mass (g) of bromocresol blue to the volume (mL) of the solvent sodium hydroxide in the bromocresol blue indicator is 1:1000, and the concentration of the sodium hydroxide is 0.1 mol / L;

[0095] (3) Preheat the dehydrated main raw materials polybutylene glycol and polyether 330N polyol to 70°C, and dissolve 1.9876g of 4,4'-dihydroxydiphenyl disulfide in N,N-dimethylformamide solution in advance;

[0096] (4) 102.786 g of polybutylene glycol, 9.87 g of polyether 330N polyol and an N,N-dimethylformamide solution containing 1.9876 g of 4,4'-dihydroxydiphenyl disulfide in step (3) were added to the container in sequence, and then 31.8657 g of the prepolymer was added and the solution was stirred at a stirring rate of 2000 r / min for 60 s; the solution was poured into a polytetrafluoroethylene container and placed in a 70°C oven for curing for 48 h, and then dried in a vacuum oven at 80°C for 24 h to remove the organic solvent to obtain a polyurethane elastomer.

[0097] (5) 10 g of choline chloride and 13 g of glycerol were stirred at 100 °C and 400 rpm for 2 h to obtain an ionic liquid.

[0098] (6) The prepared polyurethane elastomer was placed in 100 ml of N,N-dimethylformamide and soaked for 20 min. Then, 1 ml of ionic liquid was evenly coated on the surface of the self-healing polyurethane substrate and allowed to stand for 30 min. The substrate was then dried in a forced air oven at 80 °C for 6 h to obtain an ultra-soft ionic liquid conductive self-healing polyurethane elastomer.

[0099] The obtained elastomer was subjected to infrared spectroscopy analysis. -1 The peak of -NH- stretching vibration appeared at 1721cm -1 The peak of -CO- stretching vibration appears at 450 cm -1 A peak of -SS- vibration appears.

[0100] The obtained elastomer was subjected to a large strain electrical signal test. When the stretching rate reached 240%, electrical signals could be detected in the range of 0.015mA~0.018mA, indicating that the elastomer can conduct electricity under large strain.

[0101] The obtained elastomer was subjected to a small strain electrical signal test. When the stretching rate reached 100%, an electrical signal could be detected in the range of 0.006mA~0.007mA, indicating that the elastomer can conduct electricity under small strain.

[0102] The obtained elastomer was cut and then spliced, and then repaired at room temperature for 1 hour before a tensile test. Since the chemical cross-linking points were cut during the cutting process, the elongation at break was difficult to recover to that of the initial sample, but its tensile strength basically recovered to 60% of the original.

[0103] Example 4

[0104] A super-soft ionic liquid conductive self-healing polyurethane elastomer is composed of three raw material components, A, B, and C. Based on the total mass of each of the raw materials A, B, and C being 100%, the components and their mass fractions in raw material A are as follows: (HDI) 37%-39%, polytetramethylene glycol (PTMG) 61%-63%; the components and their mass fractions in raw material B are as follows: polytetramethylene glycol (PTMG) 87.6%-91.6%, polyether 330N polyol (330N) 6.7%-10.7%; and 4,4'-dihydroxydiphenyl disulfide 0.7%-2.7%; the components and their mass fractions in raw material C are as follows: choline chloride 42%-44%, glycerol 56%-58%; and auxiliary raw materials are an organic solvent (such as N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, etc.) and an indicator bromocresol blue and a toluene solution of di-n-butylamine.

[0105] The molecular weight of the polybutylene glycol is 1760-2080, the molecular weight of the polyether 330N polyol is 4600-4800, and the chain extender is an N,N-dimethylformamide solution of polybutylene glycol and 4,4'-dihydroxydiphenyl disulfide.

[0106] The mass ratio of hexamethylene diisocyanate and polybutylene glycol used in the synthetic polyurethane prepolymer is 3:5.

[0107] The ratio of the mass (g) of the polyurethane prepolymer sample to the volume (mL) of the isopropyl alcohol solvent is (3-4):500; the ratio of the mass (g) of the di-n-butylamine to the volume (mL) of the toluene solvent is 129:166; the volume ratio of the titration sample solution to the volume of the di-n-butylamine toluene solution is 2:1; the ratio of the mass (g) of the indicator bromocresol blue to the volume (mL) of the solution is 1:1000;

[0108] A method for preparing the ultra-soft ionic liquid conductive self-healing polyurethane elastomer described in this embodiment, the specific steps of the method are as follows:

[0109] (1) Add 60 g of hexamethylene diisocyanate and 100 g of polybutylene glycol into a 250 mL three-necked flask, heat it to 80 °C, stir the raw materials at a rate of 200 r / min to mix them evenly, and react for 4 h to obtain a polyurethane prepolymer;

[0110] (2) 0.3795 g of the prepolymer obtained in step (1) was dissolved in 50 mL of a toluene solution of di-n-butylamine and heated at 50° C. for 10 min to fully dissolve it. Four drops of bromocresol blue indicator were added, followed by 25 mL of isopropanol to completely dissolve the indicator. Titration with 0.1036 mol / L dilute hydrochloric acid revealed that the isocyanate content in the prepolymer was 16.7%.

[0111] The ratio of the mass (g) of bromocresol blue to the volume (mL) of the solvent sodium hydroxide in the bromocresol blue indicator is 1:1000, and the concentration of the sodium hydroxide is 0.1 mol / L;

[0112] (3) Preheat the dehydrated main raw materials polybutylene glycol and polyether 330N polyol to 70°C, and dissolve 1.9920g of 4,4'-dihydroxydiphenyl disulfide in N,N-dimethylformamide solution in advance;

[0113] (4) To the container, 102.549 g of polytetramethylene glycol, 10.33 g of polyether 330N polyol and a solution containing 1.9920 g of 4,4'-dihydroxydiphenyl disulfide in N,N-dimethylformamide were added in sequence, and after adding 32.7547 g of prepolymer, the solution was stirred at a stirring rate of 2000 r / min for 60 s; after pouring into a container of polytetrafluoroethylene, it was placed in an oven at 70°C for curing for 48 h, and then dried in a vacuum oven at 80°C for 24 h to remove the organic solvent, to obtain a polyurethane elastomer.

[0114] (5) 10 g of choline chloride and 13 g of glycerol were stirred at 100°C and 400 rpm for 2 h, to obtain an ionic liquid.

[0115] (6) The prepared polyurethane elastomer was placed in 100 ml of N,N-dimethylformamide for 20 min, and then 1 ml of ionic liquid was uniformly coated on the surface of the self-repairing polyurethane substrate, and left to stand for 30 min, and then dried in a 80°C air oven for 6 h, to obtain a super-soft ionic liquid conductive self-repairing polyurethane elastomer.

[0116] The obtained elastomer was subjected to infrared spectrum analysis, and peaks of -N-H- stretching vibration appeared at 3340 cm -1 peaks of -C-O- stretching vibration appeared at 1722 cm -1 peaks of -C-O- stretching vibration appeared at 1722 cm -1 peaks of -S-S- vibration appeared.

[0117] The obtained elastomer was subjected to large-strain electrical signal test, and electrical signals in the range of 0.015 mA to 0.018 mA could be detected when the elongation rate reached 230%, indicating that the elastomer could conduct electricity under large strain.

[0118] The obtained elastomer was subjected to small-strain electrical signal test, and electrical signals in the range of 0.006 mA to 0.007 mA could be detected when the elongation rate reached 110%, indicating that the elastomer could conduct electricity under small strain.

[0119] The obtained elastomer was cut and then spliced, and after repairing at room temperature for 1 h, the tensile test was performed, and since the chemical crosslinking points were cut during the cutting process, the elongation at break was difficult to recover to the initial sample, but the tensile strength was basically recovered to 59% of the original.

[0120] Example 5

[0121] A super-soft ionic liquid conductive self-healing polyurethane elastomer is composed of three raw material components, A, B, and C. Based on the total mass of each of the raw materials A, B, and C being 100%, the components and their mass fractions in raw material A are as follows: 37%-39% hexamethylene diisocyanate (HDI), 61%-63% polytetramethylene glycol (PTMG); the components and their mass fractions in raw material B are as follows: 87.6%-91.6% polytetramethylene glycol (PTMG), 6.7%-10.7% polyether 330N polyol (330N); and 0.7%-2.7% 4,4'-dihydroxydiphenyl disulfide. The components and their mass fractions in raw material C are as follows: 42%-44% choline chloride, and 56%-58% glycerol. Auxiliary raw materials are an organic solvent (such as N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, etc.) and a toluene solution of the indicator bromocresol blue and di-n-butylamine.

[0122] The molecular weight of the polybutylene glycol is 1760-2080, the molecular weight of the polyether 330N polyol is 4600-4800, and the chain extender is an N,N-dimethylformamide solution of polybutylene glycol and 4,4'-dihydroxydiphenyl disulfide.

[0123] The mass ratio of hexamethylene diisocyanate and polybutylene glycol used in the synthetic polyurethane prepolymer is 3:5.

[0124] The ratio of the mass (g) of the polyurethane prepolymer sample to the volume (mL) of the isopropyl alcohol solvent is (3-4):500; the ratio of the mass (g) of the di-n-butylamine to the volume (mL) of the toluene solvent is 129:166; the volume ratio of the titration sample solution to the volume of the di-n-butylamine toluene solution is 2:1; the ratio of the mass (g) of the indicator bromocresol blue to the volume (mL) of the solution is 1:1000;

[0125] A method for preparing the ultra-soft ionic liquid conductive self-healing polyurethane elastomer described in this embodiment, the specific steps of the method are as follows:

[0126] (1) Add 60 g of hexamethylene diisocyanate and 100 g of polybutylene glycol into a 250 mL three-necked flask, heat it to 80 °C, stir the raw materials at a rate of 200 r / min to mix them evenly, and react for 4 h to obtain a polyurethane prepolymer;

[0127] (2) 0.3937 g of the prepolymer obtained in step (1) was dissolved in 50 mL of a toluene solution of di-n-butylamine and heated at 50°C for 10 min to fully dissolve it. Four drops of bromocresol blue indicator were added, followed by 25 mL of isopropanol to completely dissolve the indicator. Titration with 0.1036 mol / L dilute hydrochloric acid revealed that the isocyanate content in the prepolymer was 16.9%.

[0128] The ratio of the mass (g) of bromocresol blue to the volume (mL) of the solvent sodium hydroxide in the bromocresol blue indicator is 1:1000, and the concentration of the sodium hydroxide is 0.1 mol / L;

[0129] (3) Preheat the main raw materials of polybutylene glycol and polyether 330N polyol after dehydration to 70°C, and dissolve 1.9976g of 4,4'-dihydroxydiphenyl disulfide in N,N-dimethylformamide solution in advance;

[0130] (4) 103.761 g of polybutylene glycol, 10.76 g of polyether 330N polyol and an N,N-dimethylformamide solution containing 1.9976 g of 4,4'-dihydroxydiphenyl disulfide in step (3) were added to the container in sequence, and then 33.2432 g of the prepolymer was added and the solution was stirred at a stirring rate of 2000 r / min for 60 s; the solution was poured into a polytetrafluoroethylene container and placed in a 70°C oven for curing for 48 h, and then dried in a vacuum oven at 80°C for 24 h to remove the organic solvent to obtain a polyurethane elastomer.

[0131] (5) 10 g of choline chloride and 13 g of glycerol were stirred at 100 °C and 400 rpm for 2 h to obtain an ionic liquid.

[0132] (6) The prepared polyurethane elastomer was placed in 100 ml of N,N-dimethylformamide and soaked for 20 min. Then, 1 ml of ionic liquid was evenly coated on the surface of the self-healing polyurethane substrate and allowed to stand for 30 min. The substrate was then dried in a forced air oven at 80 °C for 6 h to obtain an ultra-soft liquid-conductive self-healing polyurethane elastomer.

[0133] The obtained elastomer was subjected to infrared spectroscopy analysis. -1 The peak of -NH- stretching vibration appeared at 1721cm -1 The peak of -CO- stretching vibration appears at 453 cm -1 A peak of -SS- vibration appears.

[0134] The obtained elastomer was subjected to a large strain electrical signal test. When the stretching rate reached 260%, electrical signals could be detected in the range of 0.015mA~0.018mA, indicating that the elastomer can conduct electricity under large strain.

[0135] The obtained elastomer was subjected to a small strain electrical signal test. When the stretching rate reached 110%, an electrical signal could be detected in the range of 0.006mA~0.007mA, indicating that the elastomer can conduct electricity under small strain.

[0136] The obtained elastomer was cut and then spliced, and then repaired at room temperature for 1 hour before a tensile test. Since the chemical cross-linking points were cut during the cutting process, the elongation at break was difficult to recover to that of the initial sample, but its tensile strength basically recovered to 55% of the original.

[0137] Example 6

[0138] A super-soft ionic liquid conductive self-healing polyurethane elastomer is composed of three raw material components, A, B, and C. Based on the total mass of each of the raw materials A, B, and C being 100%, the components and their mass fractions in raw material A are as follows: 37%-39% hexamethylene diisocyanate (HDI), 61%-63% polytetramethylene glycol (PTMG); the components and their mass fractions in raw material B are as follows: 87.6%-91.6% polytetramethylene glycol (PTMG), 6.7%-10.7% polyether 330N polyol (330N); and 0.7%-2.7% 4,4'-dihydroxydiphenyl disulfide. The components and their mass fractions in raw material C are as follows: 42%-44% choline chloride, and 56%-58% glycerol. Auxiliary raw materials are an organic solvent (such as N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, etc.) and a toluene solution of the indicator bromocresol blue and di-n-butylamine.

[0139] The molecular weight of the polybutylene glycol is 1760-2080, the molecular weight of the polyether 330N polyol is 4600-4800, and the chain extender is an N,N-dimethylformamide solution of polybutylene glycol and 4,4'-dihydroxydiphenyl disulfide.

[0140] The mass ratio of hexamethylene diisocyanate and polybutylene glycol used in the synthetic polyurethane prepolymer is 3:5.

[0141] The ratio of the mass (g) of the polyurethane prepolymer sample to the volume (mL) of the isopropyl alcohol solvent is (3-4):500; the ratio of the mass (g) of the di-n-butylamine to the volume (mL) of the toluene solvent is 129:166; the volume ratio of the titration sample solution to the volume of the di-n-butylamine toluene solution is 2:1; the ratio of the mass (g) of the indicator bromocresol blue to the volume (mL) of the solution is 1:1000;

[0142] A method for preparing the ultra-soft ionic liquid conductive self-healing polyurethane elastomer described in this embodiment, the specific steps of the method are as follows:

[0143] (1) Add 60 g of hexamethylene diisocyanate and 100 g of polybutylene glycol into a 250 mL three-necked flask, heat it to 80 °C, stir the raw materials at a rate of 200 r / min to mix them evenly, and react for 4 h to obtain a polyurethane prepolymer;

[0144] (2) 0.3822 g of the prepolymer obtained in step (1) was dissolved in 50 mL of a toluene solution of di-n-butylamine and heated at 50°C for 10 min to fully dissolve it. Four drops of bromocresol blue indicator were added, followed by 25 mL of isopropanol to completely dissolve the indicator. Titration with 0.1036 mol / L dilute hydrochloric acid revealed that the isocyanate content in the prepolymer was 17.2%.

[0145] The ratio of the mass (g) of bromocresol blue to the volume (mL) of the solvent sodium hydroxide in the bromocresol blue indicator is 1:1000, and the concentration of the sodium hydroxide is 0.1 mol / L;

[0146] (3) Preheat the dehydrated main raw materials polybutylene glycol and polyether 330N polyol to 70°C, and dissolve 1.9896g of 4,4'-dihydroxydiphenyl disulfide in N,N-dimethylformamide solution in advance;

[0147] (4) 103.275 g of polybutylene glycol, 11.09 g of polyether 330N polyol and an N,N-dimethylformamide solution containing 1.9896 g of 4,4'-dihydroxydiphenyl disulfide in step (3) were added to the container in sequence, and then 31.9548 g of the prepolymer was added and the solution was stirred at a stirring rate of 2000 r / min for 60 s; the solution was poured into a polytetrafluoroethylene container and placed in a 70°C oven for curing for 48 h, and then dried in a vacuum oven at 80°C for 24 h to remove the organic solvent to obtain a polyurethane elastomer.

[0148] (5) 10 g of choline chloride and 13 g of glycerol were stirred at 100 °C and 400 rpm for 2 h to obtain an ionic liquid.

[0149] (6) The prepared polyurethane elastomer was placed in 100 ml of N,N-dimethylformamide and soaked for 20 min. Then, 1 ml of ionic liquid was evenly coated on the surface of the self-healing polyurethane substrate and allowed to stand for 30 min. The substrate was then dried in a forced air oven at 80 °C for 6 h to obtain an ultra-soft ionic liquid conductive self-healing polyurethane elastomer.

[0150] The obtained elastomer was subjected to infrared spectroscopy analysis. -1 The peak of -NH- stretching vibration appeared at 1721cm -1 The peak of -CO- stretching vibration appears at 453 cm -1 A peak of -SS- vibration appears.

[0151] The obtained elastomer was subjected to a large strain electrical signal test. When the stretching rate reached 240%, electrical signals could be detected in the range of 0.015mA~0.018mA, indicating that the elastomer can conduct electricity under large strain.

[0152] The obtained elastomer is subjected to a small strain electrical signal test, and when the tensile rate reaches 100%, an electrical signal in the range of 0.006 mA to 0.007 mA can be detected, indicating that the elastomer can conduct electricity under small strain.

[0153] The obtained elastomer is cut and then spliced, and after being repaired at room temperature for 1 h, a tensile test is performed; since the chemical crosslinking points are cut during the cutting process, the elongation at break is difficult to recover to that of the initial sample, but the tensile strength is basically recovered to 57% of the original.

[0154] To sum up, the above is only a preferred embodiment of the present application, and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An ultra-soft ionic liquid conductive self-healing polyurethane elastomer, characterized by: The raw materials of the ultra-soft ionic liquid conductive self-repairing polyurethane elastomer include component A, component B and component C; Taking the mass of component A as 100%, the mass percentages of the components in component A are as follows: Hexamethylene diisocyanate 37%~39%; Polybutylene glycol 61%~63%; Taking the mass of component B as 100%, the mass percentages of the components in component B are as follows: Polybutylene glycol 87.6%~91.6%; Polyether 330N polyol 6.7% to 10.7%; 4,4'-dihydroxydiphenyl disulfide 0.7%~2.7%; Taking the mass of the C component as 100%, the mass percentages of the components in the C component are as follows: Choline chloride 42%~44%; Glycerol 56%~58%; The molecular weight of the polybutylene glycol is 1760-2080; The molecular weight of the polyether 330N polyol is 4600-4800; The prepared polyurethane elastomer is immersed in N,N-dimethylformamide, and then the obtained ionic liquid is evenly coated on the surface of the soaked polyurethane elastomer and dried to obtain an ultra-soft ionic liquid conductive self-healing polyurethane elastomer.

2. A method for preparing the ultra-soft ionic liquid conductive self-repairing polyurethane elastomer according to claim 1, characterized in that The steps of the method include: In the first step, the hexamethylene diisocyanate and polybutylene glycol in component A are dehydrated and then mixed under nitrogen atmosphere. The mixture is then heated to 80-85°C and stirred for 4-5 hours to obtain a polyurethane prepolymer. In the second step, a portion of the polyurethane prepolymer obtained in the first step and isopropyl alcohol are mixed in a water bath at 45-55° C., with a mixing volume of L and a mixing time of 10-15 minutes. A toluene solution of di-n-butylamine and a bromocresol blue indicator are then added, followed by titration with 0.1 mol / L dilute hydrochloric acid until the solution no longer changes color within 30 seconds. The titration is then terminated, and the isocyanate content in the polyurethane prepolymer is calculated as a after the titration is completed. In the third step, the polybutylene glycol and polyether 330N polyol in component B are dehydrated; The fourth step is to dissolve the 4,4'-dihydroxydiphenyl disulfide in component B in N,N-dimethylformamide, and then mix it with part of the polyurethane prepolymer obtained in the first step, the dehydrated polybutylene glycol in component B, and the polyether 330N polyol at a mixing temperature of 30-50°C; Step 5: Stir the materials mixed in step 4, then cure them at 75-85°C for 24-48 hours, and then dry them in a vacuum oven at 75-85°C for 24-48 hours to obtain a polyurethane elastomer. Step 6: Mix the choline chloride and glycerol in material C, heat to 95-105°C, and stir to dissolve for 2-3 hours to obtain an ionic liquid; In the seventh step, the polyurethane elastomer prepared in the fifth step is soaked in N,N-dimethylformamide for 10-20 minutes, and then the ionic liquid obtained in the sixth step is evenly coated on the surface of the soaked polyurethane elastomer and dried to obtain an ultra-soft ionic liquid conductive self-healing polyurethane elastomer.

3. The method for preparing a super-soft ionic liquid conductive self-repairing polyurethane elastomer according to claim 2, characterized in that: In the second step, the ratio of polyurethane prepolymer to isopropyl alcohol is 3-4 g:500 mL; The volume ratio of the mixed volume L of the polyurethane prepolymer and isopropyl alcohol to the toluene solution of di-n-butylamine is 2:1; The ratio of the volume L of the polyurethane prepolymer and isopropyl alcohol after mixing to the bromocresol blue indicator is 1000 mL:1 g; The ratio of the mass of the di-n-butylamine to the volume of the solvent toluene is 129 g:166 ml.

4. The method for preparing a super-soft ionic liquid conductive self-repairing polyurethane elastomer according to claim 2, characterized in that: In the fourth step, the ratio of 4,4'-dihydroxydiphenyl disulfide, polyurethane prepolymer, polytetramethylene glycol (PTMG), and polyether 330N polyol satisfies the following conditions: (m1×a) / 42=R×((m2 / N1)×2+(m3 / N2)×3+(m4 / N3)×2) Wherein, m1 is the mass of polyurethane prepolymer, m2 is the mass of polybutylene glycol, m3 is the mass of polyether 330N polyol, and m4 is the mass of 4,4'-dihydroxydiphenyl disulfide; N1, is the molecular weight of polybutylene glycol; N2 is the molecular weight of polyether 330N polyol; N3 is the molecular weight of 4,4'-dihydroxydiphenyl disulfide; The value of the isocyanate group in the polyurethane prepolymer is defined as R1, and the sum of the hydroxyl groups in 4,4'-dihydroxydiphenyl disulfide, polybutylene glycol and polyether 330N polyol is R2, then R=R1 / R2, R =1.04~1.06.

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