阅读说明：本技术 一种自愈合抗老化可控降解型聚氨酯及其制备方法与应用 (Self-healing anti-aging controllable degradable polyurethane and preparation method and application thereof ) 是由 李凤龙 应邬彬 张若愚 朱锦 于 2020-11-16 设计创作，主要内容包括：本发明公开了一种自愈合抗老化可控降解型聚氨酯及其制备方法与应用。所述聚氨酯包括具有自愈合抗老化性能的硬段结构和具有可控降解功能的软段结构,所述软段结构和硬段结构交替分布；其中,所述软段结构包含可控降解的聚二醇,所述硬段结构包含具有动态共价键的扩链剂与异氰酸酯,所述聚二醇包括聚己内酯二醇和聚己二酸丁二醇酯二醇。本发明制备的自愈合抗老化可控降解型聚氨酯具有优异的力学性能、自愈合性能、抗老化性能,且具有可控降解的特点；同时本发明的制备方法具有原料易得、工艺简单等特点,在柔性器件领域有广阔的应用前景。(The invention discloses self-healing anti-aging controllably degradable polyurethane and a preparation method and application thereof. The polyurethane comprises a hard segment structure with self-healing aging resistance and a soft segment structure with controllable degradation function, wherein the soft segment structure and the hard segment structure are alternately distributed; wherein the soft segment structure contains a controllably degradable polyglycol, the hard segment structure contains a chain extender with a dynamic covalent bond and isocyanate, and the polyglycol comprises polycaprolactone diol and polybutylene adipate diol. The self-healing anti-aging controllably degradable polyurethane prepared by the invention has excellent mechanical property, self-healing property and anti-aging property, and has the characteristic of controllable degradation; meanwhile, the preparation method has the characteristics of easily obtained raw materials, simple process and the like, and has wide application prospect in the field of flexible devices.)

1. A self-healing anti-aging controllable degradable polyurethane is characterized in that: the polyurethane comprises a hard segment structure with self-healing aging resistance and a soft segment structure with controllable degradation function, wherein the soft segment structure and the hard segment structure are alternately distributed; wherein the soft segment structure contains a controllably degradable polyglycol, the hard segment structure contains a chain extender with a dynamic covalent bond and isocyanate, and the polyglycol comprises polycaprolactone diol and polybutylene adipate diol.

2. A self-healing anti-aging controllably degradable polyurethane according to claim 1, characterized in that: the crystallinity of the polyurethane is 10-70%;

and/or hydroxyl groups are arranged at two ends of a molecular chain of the polyglycol; preferably, the molecular weight of the polyglycol is 600-6000 g/mol.

3. A self-healing anti-aging controllably degradable polyurethane according to claim 1, characterized in that: the chain extender comprises a small molecule diol having dynamic covalent bonds;

preferably, the small molecule diol has a structure shown in formula (I):

wherein R is any one of alkyl, alkenyl and alkynyl, and x and y are both selected from 1-10;

preferably, the dynamic bond comprises any one of a dynamic disulfide bond, a dynamic borate isocyanate and a dynamic schiff base bond;

preferably, the molecular weight of the small molecule diol is 100-1000 g/mol.

4. A self-healing anti-aging controllably degradable polyurethane according to claim 1, characterized in that: the isocyanate comprises a diisocyanate; preferably, the diisocyanate includes any one or a combination of two or more of isophorone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, 1, 5-naphthalene diisocyanate, p-phenylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, 3 ' -dimethyl-4, 4 ' -biphenyl diisocyanate, cyclohexane dimethylene diisocyanate, 4 ' -dicyclohexylmethane diisocyanate, and 3,3 ' -dimethyl-4, 4 ' -diphenylmethane diisocyanate.

5. A self-healing anti-aging controllably degradable polyurethane according to any one of claims 1 to 4, characterized in that: the self-healing speed of the self-healing anti-aging controllably degradable polyurethane at room temperature is 0.1-2 mu m/min;

and/or the self-healing anti-aging controllably degradable polyurethane is soaked in an alkali solution with the pH value of 14 for 8 days, and the mass loss of the polyurethane is more than 50%.

6. The method for preparing self-healing anti-aging controllably degradable polyurethane according to any one of claims 1 to 5, comprising:

under the protective atmosphere, reacting a mixed reaction system containing polyglycol, isocyanate, a chain extender, a catalyst, isocyanate and a solvent for 1-48 hours at the temperature of 25-100 ℃ to prepare the self-healing anti-aging controllably degradable polyurethane.

7. The method according to claim 6, comprising:

under a protective atmosphere, mixing polyglycol, isocyanate, a chain extender, a catalyst and a solvent, heating at 25-100 ℃ until the mixture is completely dissolved, then adding isocyanate to form the mixed reaction system, controlling the concentration of reactants in the mixed reaction system to be 10-50 wt%, then reacting at 25-100 ℃ for 1-48h, and then carrying out post-treatment to obtain the self-healing anti-aging controllably degradable polyurethane.

8. The production method according to claim 6 or 7, characterized in that: the molar ratio of the hydroxyl group of the polyglycol to the isocyanate group of the isocyanate in the mixed reaction system is 0.5: 1-2: 1;

and/or the molar ratio of polybutylene adipate diol to polycaprolactone diol in the polyglycol is 0.1: 1-10: 1;

and/or the mass ratio of the chain extender to the polyglycol is 1: 99-99: 1;

and/or, the content of the catalyst in the mixed reaction system is 0.1-1 wt%;

and/or the protective atmosphere comprises an inert gas atmosphere and/or a nitrogen atmosphere, preferably an argon atmosphere;

and/or the catalyst comprises any one or the combination of more than two of bis-dimethylamino ethyl ether, pentamethyl diethylenetriamine, dimethyl cyclohexylamine, dibutyltin dilaurate, organic bismuth and triazine trimerization catalyst;

and/or the solvent comprises tetrahydrofuran and/or N, N-dimethylformamide.

9. The method of manufacturing according to claim 7, wherein the post-treatment comprises: after the reaction is finished, washing a solid obtained by the reaction with a washing solution, and then drying in vacuum at 40-120 ℃ for 6-48h to obtain the self-healing anti-aging controllably degradable polyurethane; preferably, the washing liquid comprises distilled water and/or methanol.

10. Use of the self-healing anti-aging controllably degradable polyurethane as defined in any one of claims 1 to 5 in the field of flexible devices; preferably, the use comprises the use of the self-healing anti-aging controllably degradable polyurethane in flexible electronic devices, preferably electronic skin matrix materials.

Technical Field

The invention belongs to the technical field of polyurethane, and particularly relates to self-healing anti-aging controllably degradable polyurethane and a preparation method and application thereof.

Background

The polyurethane has a soft segment and a hard segment which are thermodynamically incompatible, and micro-phase separation is easy to occur, so that the polyurethane has excellent mechanical properties such as stretchability, good toughness and the like, has a large adjustable range of the mechanical properties, and is a suitable base material for electronic skins. However, when the composite material is frequently used, the composite material is inevitably scratched, and the self-healing property of the base material is particularly important. At present, a lot of students make outstanding contributions in self-healing polyurethane, and usually introduce dynamic bonds into a molecular chain to achieve the self-healing effect, such as hydrogen bonds, dynamic disulfide bonds, dynamic metal coordination bonds, D-A reaction and the like. The matrix material has self-healing performance, can effectively prolong the service life of the electronic skin, has excellent mechanical property and quick self-healing performance which are necessary properties of the existing electronic skin matrix material, and the degradable matrix material is a great trend of the development of the electronic skin.

Along with the continuous development of electronic products, people pay more and more attention to the problem of electronic garbage. Many researchers have begun to apply degradable materials to flexible electronic devices to reduce environmental pollution. The device can be degraded after being used, and is expected to solve the problem of environmental pollution caused by electronic waste, but the anti-aging effect is also a problem of great concern in the actual use process. At present, studies on the anti-aging aspect of electronic skin are rarely reported. For most materials there is usually a trade-off between degradability and aging resistance, i.e. rapidly degradable materials are usually susceptible to aging, and excellent aging resistance may lead to poor degradability. The electronic skin substrate has excellent anti-aging performance during use, and controllable degradation after being discarded remains a great challenge in current research.

Therefore, it is an urgent need to prepare a self-healing, anti-aging and controllably degradable polyurethane for electronic skin, and until now, no documents and patents on polyurethane with high-efficiency self-healing, anti-aging and controllably degradable performances are found in the prior art.

Disclosure of Invention

The invention mainly aims to provide self-healing anti-aging controllably degradable polyurethane, a preparation method and application thereof, so as to overcome the defects of the prior art.

In order to achieve the purpose, the technical scheme adopted by the invention comprises the following steps:

the embodiment of the invention provides self-healing anti-aging controllably degradable polyurethane, which comprises a hard segment structure with self-healing anti-aging performance and a soft segment structure with controllably degradable function, wherein the soft segment structure and the hard segment structure are alternately distributed; wherein the soft segment structure contains a controllably degradable polyglycol, the hard segment structure contains a chain extender with a dynamic covalent bond and isocyanate, and the polyglycol comprises polycaprolactone diol and polybutylene adipate diol.

Further, the mass loss of the self-healing anti-aging controllably degradable polyurethane in the alkali solution is 50-100%.

In the invention, the self-healing anti-aging controllably degradable polyurethane plays a main role in a hard segment in the using process, thereby playing a self-healing anti-aging function; after use, the soft segment plays a main role and plays a role in controllable degradation.

The embodiment of the invention also provides a preparation method of the self-healing anti-aging controllably degradable polyurethane, which comprises the following steps:

under the protective atmosphere, reacting a mixed reaction system containing polyglycol, isocyanate, a chain extender, a catalyst, isocyanate and a solvent at 25-100 ℃ for 1-48h to obtain the self-healing anti-aging controllably degradable polyurethane.

The embodiment of the invention also provides application of the self-healing anti-aging controllably degradable polyurethane in the field of flexible devices.

Compared with the prior art, the invention has the beneficial effects that:

(1) the self-healing anti-aging controllably degradable polyurethane prepared by the invention has excellent mechanical property, the mechanical strength of the polyurethane reaches 4.6MPa, and the fracture toughness reaches 19.5MJ/m³At the same time, the polyurethane is at room temperatureThe self-healing speed can reach 2 mu m/min and gradually increases along with the rise of the temperature; after the artificial hernia aging box is placed for 12 days, the properties of the polyurethane are not changed; the mass loss of the polyurethane in an alkaline solution with the pH value lower than 12 within 8 days is less than 10 percent, which indicates that the polyurethane is not easy to degrade in daily use and use fields and ensures the use effect; only when the pH value reaches 14, the mass loss reaches more than 50% in 8 days, and the polycaprolactone diol can be degraded only in a specific environment, so that the purpose of controllable degradation is achieved, and meanwhile, the polycaprolactone diol is biodegradable and is environment-friendly;

(2) the preparation method of the self-healing anti-aging controllable degradable polyurethane provided by the invention has the characteristics of easily available raw materials, simple process, multifunctional integration and the like, and the polyurethane is synthesized by using the bio-based degradable polycaprolactone diol and the poly (butylene adipate) diol, so that the controllable degradation of the polyurethane is realized; when the pH value of the alkali liquor is less than 12, the concentration of the alkali is insufficient, so that the ester bond position is not broken, when the pH value reaches 14, the ester bond can be broken, the purpose of controllable degradation is achieved, and the prepared self-healing anti-aging controllable degradation type polyurethane has a wide application prospect in the field of flexible devices.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only some embodiments recorded in the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a self-healing anti-aging controllably degradable polyurethane according to an exemplary embodiment of the present invention;

FIG. 2 is a schematic illustration of the structure of a controlled degradation polyglycol in accordance with an exemplary embodiment of the present invention;

FIG. 3 is a nuclear magnetic resonance hydrogen spectrum of the self-healing anti-aging controllably degradable polyurethane prepared in examples 1-5 of the present invention;

FIGS. 4a to 4d are graphs showing the results of a polarizing microscope for self-healing tests at room temperature on the self-healing anti-aging controllably degradable polyurethane prepared in example 1 of the present invention;

fig. 5 is a graph showing the results of the changes in light transmittance of the self-healing anti-aging controllably degradable polyurethane prepared in example 1 of the invention when placed in an artificial hernia aging box for different periods of time;

FIG. 6 is a graph showing the change of mass loss of the self-healing anti-aging controllably degradable polyurethane prepared in example 1 of the present invention when placed in an alkaline solution for different periods of time;

FIG. 7 is a graph showing the change of molecular weight of the self-healing anti-aging controllably degradable polyurethane prepared in example 1 of the present invention when placed in an alkaline solution for different periods of time;

FIG. 8 is a graph showing the change in mass loss of a comparative sample of the polyurethane prepared in comparative example 1 of the present invention left in an alkali solution for various times;

FIG. 9 is a graph showing the mechanical properties of the self-healing anti-aging controllably degradable polyurethane prepared in examples 1 to 5 of the present invention;

FIG. 10 is a DSC chart of the polyurethanes prepared in examples 1-5 of the present invention, comparative example 1;

FIG. 11 is a graph showing the mechanical properties of the polyurethane prepared in comparative example 1 of the present invention.

Detailed Description

In view of the defects of the prior art, the inventor of the present invention provides a technical scheme of the present invention through long-term research and a great deal of practice, wherein a self-healing anti-aging controllably degradable polyurethane is prepared mainly by a controllably degradable polyglycol soft segment, a small molecular diol containing a dynamic covalent bond and isocyanate, and the introduction of the controllably degradable polyglycol soft segment enables the material to be controllably degraded after use; due to the introduction of the hard segment disulfide bond, the material can play the functions of self-healing and ageing resistance in the using process, so that the material can be durable.

The technical solutions of the present invention will be described clearly and completely below, and it should be apparent that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

One aspect of the embodiment of the invention provides self-healing anti-aging controllably degradable polyurethane, which comprises a hard segment structure with self-healing anti-aging performance and a soft segment structure with controllably degradable function, wherein the soft segment structure and the hard segment structure are alternately distributed; wherein the soft segment structure comprises a controllably degradable polyglycol, the hard segment structure comprises a chain extender with dynamic covalent bonds and isocyanate, and the polyglycol comprises polycaprolactone diol and polybutylene adipate diol.

The structural schematic diagram of the self-healing anti-aging controllably degradable polyurethane disclosed by the invention is shown in fig. 1, and the self-healing anti-aging controllably degradable polyurethane comprises a hard segment structure with self-healing anti-aging performance and a soft segment structure with controllably degradable function, wherein the soft segment structure and the hard segment structure are alternately distributed.

Further, the crystallinity of the polyurethane is 10 to 70 percent.

In some more specific embodiments, the polyglycol has hydroxyl groups at two ends of the molecular chain, and the polyglycol is soaked in alkaline solution with pH value of 14 for 8 days, and the mass loss of polyurethane is more than 50%

Further, the molecular weight of the polyglycol is 600-6000 g/mol.

Further, the polyglycol is a controllable degradation type polyglycol (the structural schematic diagram of the polyglycol is shown in fig. 2).

In some more specific embodiments, the chain extender includes, but is not limited to, a small molecule diol with dynamic covalent bonds.

Further, the chain extender is bis (4-hydroxyphenyl) disulfide.

Further, the small molecule diol has a structure shown in a formula (I):

wherein R is any one of alkyl, alkenyl and alkynyl, and x and y are both selected from 1-10;

further, the dynamic bond includes any one of a dynamic disulfide bond, a dynamic boronate isocyanate, and a dynamic schiff base bond, but is not limited thereto.

Further, the molecular weight of the small molecular diol is 100-1000 g/mol.

In some more specific embodiments, the isocyanate includes a diisocyanate, and is not limited thereto.

Further, the diisocyanate includes any one or a combination of two or more of isophorone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, 1, 5-naphthalene diisocyanate, p-phenylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, 3 ' -dimethyl-4, 4 ' -biphenyl diisocyanate, cyclohexane dimethylene diisocyanate, 4 ' -dicyclohexylmethane diisocyanate, 3 ' -dimethyl-4, 4 ' -diphenylmethane diisocyanate, and is not limited thereto.

In some more specific embodiments, the self-healing anti-aging controllably degradable polyurethane has a self-healing speed of 0.1 to 2 μm/min at room temperature.

Furthermore, the self-healing anti-aging controllably degradable polyurethane has the tensile strength of 4.6MPa and the fracture toughness of 19.5MJ/m at the tensile rate of 50mm/min³。

Furthermore, after the self-healing anti-aging controllably degradable polyurethane is placed in an aging box for 12 days, all performances of the self-healing anti-aging controllably degradable polyurethane are not changed.

Further, the mass loss of the self-healing anti-aging controllably degradable polyurethane in the alkali solution is 50-100%.

In another aspect of the embodiment of the present invention, a preparation method of the self-healing anti-aging controllably degradable polyurethane is further provided, where the preparation method includes:

under the protective atmosphere, reacting a mixed reaction system containing polyglycol, isocyanate, a chain extender, a catalyst, isocyanate and a solvent at 25-100 ℃ for 1-48h to obtain the self-healing anti-aging controllably degradable polyurethane.

In some more specific embodiments, the preparation method specifically comprises:

under a protective atmosphere, mixing polyglycol, isocyanate, a chain extender, a catalyst and a solvent, heating at 25-100 ℃ until the mixture is completely dissolved, then adding isocyanate to form the mixed reaction system, controlling the concentration of reactants in the mixed reaction system to be 10-50 wt%, then reacting at 25-100 ℃ for 1-48h, and then carrying out post-treatment to obtain the self-healing anti-aging controllable degradable polyurethane.

Further, the molar ratio of the hydroxyl group of the polyglycol to the isocyanate group of the isocyanate in the mixed reaction system is 0.5: 1-2: 1.

Further, the molar ratio of polybutylene adipate glycol to polycaprolactone glycol in the polyglycol is 0.1: 1-10: 1.

Further, the mass ratio of the chain extender to the polyglycol is 1: 99-99: 1.

Further, the content of the catalyst in the mixed reaction system is 0.1-1 wt%.

Further, the protective atmosphere includes an inert gas atmosphere or a nitrogen atmosphere, preferably an argon atmosphere, and is not limited thereto.

Further, the catalyst includes any one or a combination of two or more of bis dimethylamino ethyl ether, pentamethyl diethylenetriamine, dimethyl cyclohexylamine, dibutyltin dilaurate, organic bismuth and triazine trimerization catalyst, and is not limited thereto.

Further, the solvent includes tetrahydrofuran, and is not limited thereto.

In some more specific embodiments, the post-processing comprises: and after the reaction is finished, washing the solid obtained by the reaction with a washing solution, and then drying in vacuum at 40-120 ℃ for 6-48h to obtain the self-healing anti-aging controllably degradable polyurethane.

Further, the washing solution includes distilled water or methanol, and is not limited thereto.

In another aspect of the embodiment of the invention, the application of the self-healing anti-aging controllably degradable polyurethane in the field of flexible devices is also provided.

Further, the application comprises the application of the self-healing anti-aging controllably degradable polyurethane in flexible electronic devices, preferably in electronic skin matrix materials.

The controllable degradation of the self-healing anti-aging controllable degradable polyurethane provided by the invention is realized by polycaprolactone diol and polybutylene adipate diol, wherein the polycaprolactone diol is biodegradable, the crystallinity of polycaprolactone is relatively weak, and the crystallinity of the polybutylene adipate diol is relatively strong. When the content of the polybutylene adipate glycol is large, the crystallinity is relatively large, ester bonds are relatively difficult to break, and the degradation performance is influenced. The crystallinity of the polyurethane is controlled by adjusting the content of the polybutylene adipate diol and the polycaprolactone diol, so that the purpose of controllable degradation is achieved.

The technical solutions of the present invention will be further described in detail below with reference to several preferred embodiments and the accompanying drawings, which are implemented on the premise of the technical solutions of the present invention, and a detailed implementation manner and a specific operation process are provided, but the protection scope of the present invention is not limited to the following embodiments.

The experimental materials used in the examples used below were commercially available from conventional biochemical reagents companies, unless otherwise specified.

In the examples of the present invention, NMR spectroscopy¹H-NMR was measured using 400 AVANCE type III Spectrometer (Spectrometer) from Bruker, 400MHz, deuterated chloroform (CDCl)₃) (ii) a The self-healing test was performed by means of an optical microscope (Olympus/BX 51TF Instec H601, Japan) equipped with a hot stage. Aging test

Is carried out by an artificial hernia aging test chamber (Q-SUNXE-3 HS). The mechanical properties of the polyurethane test specimens were measured on a 1KN universal tester (UTM, Zwick Instruments, Model: Z1.0) according to the test standard ASTM D882, at a tensile rate of 5 mm/min.

Example 1

Fresh polybutylene adipate diol, polycaprolactone diol, bis (4-hydroxyphenyl) disulfide, dibutyltin dilaurate and tetrahydrofuran were added to a three-necked reactor equipped with a mechanical stirrer in a glove box charged with 99.999% Ar to perform a one-step process reaction, wherein [ polybutylene adipate diol + polycaprolactone diol ]/[ bis (4-hydroxyphenyl) disulfide ]: 1/99 (mass ratio), the molecular weights of the polybutylene adipate diol and the polycaprolactone diol were each 600g/mol, the molar ratio of polybutylene adipate diol to polycaprolactone diol was 1:1, dibutyltin dilaurate accounts for 0.1 wt% of the total mass of reactants, the molar ratio of hydroxyl groups to isocyanate groups is 0.5:1, the concentration of all reactants is 10 wt%, the reaction temperature is 25 ℃, the reaction time is 1h, finally, polymer precipitates are washed for a plurality of times by distilled water and dried in vacuum at 60 ℃ for 12h to constant weight to obtain the polyurethane PU-1 (a nuclear magnetic resonance hydrogen spectrogram is shown in figure 3, the self-healing performance is shown in figure 4, the anti-aging performance is shown in figure 5, the degradability is shown in figure 6, and the mechanical performance is shown in figure 7)

Example 2

Fresh polybutylene adipate diol, polycaprolactone diol, bis (4-hydroxyphenyl) disulfide, dibutyltin dilaurate, and tetrahydrofuran were charged in a glove box charged with 99.999% Ar to a three-necked reactor equipped with a mechanical stirrer for a one-step reaction. Wherein [ polybutylene adipate diol + polycaprolactone diol ]/[ bis (4-hydroxyphenyl) disulfide ]/[ 50/50 (mass ratio), the molecular weights of the polybutylene adipate diol and the polycaprolactone diol are both 600g/mol, and the molar ratio of the polybutylene adipate diol to the polycaprolactone diol is 1:1, dibutyltin dilaurate accounts for 0.1 wt% of the total mass of reactants, the molar ratio of hydroxyl groups to isocyanate groups is 0.5:1, the concentration of all reactants is 10 wt%, the reaction temperature is 25 ℃, the reaction time is 1h, finally, the polymer precipitate is washed for a plurality of times by distilled water, and dried in vacuum at 60 ℃ for 12h to constant weight, so that the polyurethane PU-2 is obtained. (the hydrogen spectrum of nuclear magnetic resonance is shown in FIG. 3, and the mechanical properties are shown in FIG. 7)

Example 3

Fresh polybutylene adipate diol, polycaprolactone diol, bis (4-hydroxyphenyl) disulfide, dibutyltin dilaurate and tetrahydrofuran were added to a three-necked reactor equipped with a mechanical stirrer in a glove box charged with 99.999% Ar to perform a one-step process reaction, wherein [ polybutylene adipate diol + polycaprolactone diol ]/[ bis (4-hydroxyphenyl) disulfide ]: 99/1 (mass ratio), the molecular weights of the polybutylene adipate diol and the polycaprolactone diol were each 600g/mol, the molar ratio of polybutylene adipate diol to polycaprolactone diol was 1:1, dibutyltin dilaurate accounts for 0.1 wt% of the total mass of reactants, the molar ratio of hydroxyl groups to isocyanate groups is 0.5:1, the concentration of all reactants is 10 wt%, the reaction temperature is 25 ℃, the reaction time is 1h, finally, the polymer precipitate is washed for a plurality of times by distilled water, and dried in vacuum at 60 ℃ for 12h to constant weight, so that the polyurethane PU-3 is obtained. (the hydrogen spectrum of nuclear magnetic resonance is shown in FIG. 3, and the mechanical properties are shown in FIG. 7)

Example 4

Fresh polybutylene adipate diol, polycaprolactone diol, bis (4-hydroxyphenyl) disulfide, dibutyltin dilaurate and tetrahydrofuran were added to a three-necked reactor equipped with a mechanical stirrer in a glove box charged with 99.999% Ar to perform a one-step process reaction, wherein [ polybutylene adipate diol + polycaprolactone diol ]/[ bis (4-hydroxyphenyl) disulfide ]: 1/99 (mass ratio), the molecular weights of the polybutylene adipate diol and the polycaprolactone diol were 6000g/mol, the molar ratio of polybutylene adipate diol to polycaprolactone diol was 1:1, dibutyltin dilaurate accounts for 0.1 wt% of the total mass of reactants, the molar ratio of hydroxyl groups to isocyanate groups is 0.5:1, the concentration of all reactants is 10 wt%, the reaction temperature is 25 ℃, the reaction time is 1h, finally, the polymer precipitate is washed for a plurality of times by distilled water, and dried in vacuum at 60 ℃ for 12h to constant weight, so that the polyurethane PU-4 is obtained. (the hydrogen spectrum of nuclear magnetic resonance is shown in FIG. 3, and the mechanical properties are shown in FIG. 7)

Example 5

Fresh polybutylene adipate diol, polycaprolactone diol, bis (4-hydroxyphenyl) disulfide, dimethylaminoethyl ether and tetrahydrofuran were added to a three-necked reactor equipped with a mechanical stirrer in a glove box charged with 99.999% Ar to conduct a one-step reaction, wherein [ polybutylene adipate diol + polycaprolactone diol ]/[ bis (4-hydroxyphenyl) disulfide ]: 1/99 (mass ratio), the molecular weights of the polybutylene adipate diol and polycaprolactone diol were each 2000g/mol, the molar ratio of polybutylene adipate diol to polycaprolactone diol was 1:1, dimethylamino ethyl ether accounts for 0.1 wt% of the total mass of reactants, the molar ratio of hydroxyl groups to isocyanate groups is 0.5:1, the concentration of all reactants is 10 wt%, the reaction temperature is 25 ℃, the reaction time is 1h, finally, polymer precipitate is washed for a plurality of times by distilled water, and vacuum drying is carried out at 60 ℃ for 12h to constant weight, so as to obtain the polyurethane PU-5. (the hydrogen spectrum of nuclear magnetic resonance is shown in FIG. 3, and the mechanical properties are shown in FIG. 7)

Example 6

Fresh polybutylene adipate diol, polycaprolactone diol, bis (4-hydroxyphenyl) disulfide, dimethylaminoethyl ether and tetrahydrofuran were added to a three-necked reactor equipped with a mechanical stirrer in a glove box charged with 99.999% Ar to conduct a one-step reaction, wherein [ polybutylene adipate diol + polycaprolactone diol ]/[ bis (4-hydroxyphenyl) disulfide ]: 1/99 (mass ratio), the molecular weights of the polybutylene adipate diol and polycaprolactone diol were each 600g/mol, the molar ratio of polybutylene adipate diol to polycaprolactone diol was 1:1, dimethylamino ethyl ether accounts for 1 wt% of the total mass of reactants, the molar ratio of hydroxyl groups to isocyanate groups is 0.5:1, the concentration of all reactants is 10 wt%, the reaction temperature is 25 ℃, the reaction time is 1h, finally, polymer precipitates are washed for a plurality of times by distilled water, and the polymer precipitates are dried in vacuum at the temperature of 60 ℃ for 12h until the weight is constant, so that the polyurethane PU-6 is obtained.

Example 7

Fresh polybutylene adipate diol, polycaprolactone diol, bis (4-hydroxyphenyl) disulfide, dimethylaminoethyl ether and tetrahydrofuran were added to a three-necked reactor equipped with a mechanical stirrer in a glove box charged with 99.999% Ar to conduct a one-step reaction, wherein [ polybutylene adipate diol + polycaprolactone diol ]/[ bis (4-hydroxyphenyl) disulfide ]: 1/99 (mass ratio), the molecular weights of the polybutylene adipate diol and polycaprolactone diol were each 600g/mol, the molar ratio of polybutylene adipate diol to polycaprolactone diol was 1: 2, dimethylamino ethyl ether accounts for 0.5 wt% of the total mass of reactants, the molar ratio of hydroxyl groups to isocyanate groups is 0.5:1, the concentration of all reactants is 10 wt%, the reaction temperature is 25 ℃, the reaction time is 1h, finally, polymer precipitate is washed for a plurality of times by distilled water, and vacuum drying is carried out at 60 ℃ for 12h to constant weight, so as to obtain the polyurethane PU-7.

Example 8

Fresh polybutylene adipate diol, polycaprolactone diol, bis (4-hydroxyphenyl) disulfide, dimethylaminoethyl ether and tetrahydrofuran were added to a three-necked reactor equipped with a mechanical stirrer in a glove box charged with 99.999% Ar to conduct a one-step reaction, wherein [ polybutylene adipate diol + polycaprolactone diol ]/[ bis (4-hydroxyphenyl) disulfide ]: 1/99 (mass ratio), the molecular weights of the polybutylene adipate diol and polycaprolactone diol were each 2000g/mol, the molar ratio of polybutylene adipate diol to polycaprolactone diol was 1: 2, dimethylamino ethyl ether accounts for 0.1 wt% of the total mass of reactants, the molar ratio of hydroxyl groups to isocyanate groups is 2:1, the concentration of all reactants is 10 wt%, the reaction temperature is 25 ℃, the reaction time is 1h, finally, polymer precipitates are washed for a plurality of times by distilled water, and the polymer precipitates are dried in vacuum at the temperature of 60 ℃ for 12h until the weight is constant, so that the polyurethane PU-8 is obtained.

Example 9

Fresh polybutylene adipate diol, polycaprolactone diol, bis (4-hydroxyphenyl) disulfide, organobismuth and tetrahydrofuran were added to a three-necked reactor equipped with a mechanical stirrer in a glove box charged with 99.999% Ar in a one-step reaction, wherein [ polybutylene adipate diol + polycaprolactone diol ]/[ bis (4-hydroxyphenyl) disulfide ]: 1/99 (mass ratio), the molecular weights of the polybutylene adipate diol and the polycaprolactone diol were each 600g/mol, the molar ratio of polybutylene adipate diol to polycaprolactone diol was 1: 5, organic bismuth accounts for 0.1 wt% of the total mass of reactants, the molar ratio of hydroxyl groups to isocyanate groups is 1:1, the concentration of all reactants is 10 wt%, the reaction temperature is 25 ℃, the reaction time is 1h, finally, polymer precipitate is washed for a plurality of times by distilled water, and is dried in vacuum at 60 ℃ for 12h to constant weight, so that the polyurethane PU-9 is obtained.

Example 10

Fresh polybutylene adipate diol, polycaprolactone diol, bis (4-hydroxyphenyl) disulfide, dibutyltin dilaurate and tetrahydrofuran were added to a three-necked reactor equipped with a mechanical stirrer in a glove box charged with 99.999% Ar to perform a one-step process reaction, wherein [ polybutylene adipate diol + polycaprolactone diol ]/[ bis (4-hydroxyphenyl) disulfide ]: 1/99 (mass ratio), the molecular weights of the polybutylene adipate diol and the polycaprolactone diol were each 600g/mol, the molar ratio of polybutylene adipate diol to polycaprolactone diol was 1: 5, dibutyltin dilaurate accounts for 0.1 wt% of the total mass of reactants, the molar ratio of hydroxyl groups to isocyanate groups is 0.5:1, the concentration of all reactants is 50 wt%, the reaction temperature is 25 ℃, the reaction time is 1h, finally, the polymer precipitate is washed for a plurality of times by distilled water, and dried in vacuum at 60 ℃ for 12h to constant weight, so that the polyurethane PU-10 is obtained.

Example 11

Fresh polybutylene adipate diol, polycaprolactone diol, bis (4-hydroxyphenyl) disulfide, dibutyltin dilaurate, and tetrahydrofuran were charged in a glove box charged with 99.999% Ar to a three-necked reactor equipped with a mechanical stirrer for a one-step reaction. Wherein [ polybutylene adipate diol + polycaprolactone diol ]/[ bis (4-hydroxyphenyl) disulfide ]/[ 1/99 (mass ratio), the molecular weights of the polybutylene adipate diol and the polycaprolactone diol are both 600g/mol, and the molar ratio of the polybutylene adipate diol to the polycaprolactone diol is 1: 5, dibutyltin dilaurate accounts for 0.1 wt% of the total mass of reactants, the molar ratio of hydroxyl groups to isocyanate groups is 0.5:1, the concentration of all reactants is 30 wt%, the reaction temperature is 25 ℃, the reaction time is 1h, finally, the polymer precipitate is washed for a plurality of times by distilled water, and dried in vacuum at 60 ℃ for 12h to constant weight, so that the polyurethane PU-11 is obtained.

Example 12

Fresh polybutylene adipate diol, polycaprolactone diol, bis (4-hydroxyphenyl) disulfide, dibutyltin dilaurate and tetrahydrofuran were added to a three-necked reactor equipped with a mechanical stirrer in a glove box charged with 99.999% Ar to perform a one-step process reaction, wherein [ polybutylene adipate diol + polycaprolactone diol ]/[ bis (4-hydroxyphenyl) disulfide ]: 1/99 (mass ratio), the molecular weights of the polybutylene adipate diol and the polycaprolactone diol were each 600g/mol, the molar ratio of polybutylene adipate diol to polycaprolactone diol was 1: 5, dibutyltin dilaurate accounts for 0.1 wt% of the total mass of the reactants, the molar ratio of hydroxyl groups to isocyanate groups is 0.5:1, the concentration of all reactants is 10 wt%, the reaction temperature is 100 ℃, and the reaction time is 1 h. And finally washing the polymer precipitate with distilled water for several times, and drying in vacuum at 60 ℃ for 12h to constant weight to obtain the polyurethane PU-12.

Example 13

Fresh polybutylene adipate diol, polycaprolactone diol, bis (4-hydroxyphenyl) disulfide, dibutyltin dilaurate and tetrahydrofuran were added to a three-necked reactor equipped with a mechanical stirrer in a glove box charged with 99.999% Ar to perform a one-step process reaction, wherein [ polybutylene adipate diol + polycaprolactone diol ]/[ bis (4-hydroxyphenyl) disulfide ]: 1/99 (mass ratio), the molecular weights of the polybutylene adipate diol and the polycaprolactone diol were each 600g/mol, the molar ratio of polybutylene adipate diol to polycaprolactone diol was 1: 5, dibutyltin dilaurate accounts for 0.1 wt% of the total mass of the reactants, the molar ratio of hydroxyl groups to isocyanate groups is 0.5:1, the concentration of all reactants is 10 wt%, the reaction temperature is 60 ℃, and the reaction time is 1 h. Finally, washing the polymer precipitate with distilled water for several times, and drying in vacuum at 60 ℃ for 12h to constant weight to obtain the polyurethane PU-13.

Example 14

Fresh polybutylene adipate diol, polycaprolactone diol, bis (4-hydroxyphenyl) disulfide, dibutyltin dilaurate and tetrahydrofuran were added to a three-necked reactor equipped with a mechanical stirrer in a glove box charged with 99.999% Ar to perform a one-step process reaction, wherein [ polybutylene adipate diol + polycaprolactone diol ]/[ bis (4-hydroxyphenyl) disulfide ]: 1/99 (mass ratio), the molecular weights of the polybutylene adipate diol and the polycaprolactone diol were each 600g/mol, the molar ratio of polybutylene adipate diol to polycaprolactone diol was 1: 5, dibutyltin dilaurate accounts for 0.1 wt% of the total mass of the reactants, the molar ratio of hydroxyl groups to isocyanate groups is 0.5:1, the concentration of all reactants is 10 wt%, the reaction temperature is 25 ℃, and the reaction time is 48 h. Finally, washing the polymer precipitate with distilled water for several times, and drying in vacuum at 40 ℃ for 48h to constant weight to obtain the polyurethane PU-14.

Example 15

Fresh polybutylene adipate diol, polycaprolactone diol, bis (4-hydroxyphenyl) disulfide, dibutyltin dilaurate and tetrahydrofuran were added to a three-necked reactor equipped with a mechanical stirrer in a glove box charged with 99.999% Ar to perform a one-step process reaction, wherein [ polybutylene adipate diol + polycaprolactone diol ]/[ bis (4-hydroxyphenyl) disulfide ]: 50/50 (mass ratio), the molecular weights of the polybutylene adipate diol and polycaprolactone diol were each 3000g/mol, the molar ratio of polybutylene adipate diol to polycaprolactone diol was 1: 5, dibutyltin dilaurate accounts for 0.5 wt% of the total mass of reactants, the molar ratio of hydroxyl groups to isocyanate groups is 1:1, the concentration of all reactants is 20 wt%, the reaction temperature is 50 ℃, the reaction time is 24 hours, finally, the polymer precipitate is washed for a plurality of times by distilled water, and is dried in vacuum at 50 ℃ for 24 hours to constant weight, so that the polyurethane PU-15 is obtained.

Example 16

Fresh polybutylene adipate diol, polycaprolactone diol, bis (4-hydroxyphenyl) disulfide, dibutyltin dilaurate and tetrahydrofuran were added to a three-necked reactor equipped with a mechanical stirrer in a glove box charged with 99.999% Ar to perform a one-step process reaction, wherein [ polybutylene adipate diol + polycaprolactone diol ]/[ bis (4-hydroxyphenyl) disulfide ]: 99/1 (mass ratio), the molecular weights of the polybutylene adipate diol and the polycaprolactone diol were 6000g/mol, the molar ratio of polybutylene adipate diol to polycaprolactone diol was 0.1: 1, dibutyltin dilaurate accounts for 1.0 wt% of the total mass of reactants, the molar ratio of hydroxyl groups to isocyanate groups is 2:1, the concentration of all reactants is 50 wt%, the reaction temperature is 100 ℃, the reaction time is 1h, finally, the polymer precipitate is washed for a plurality of times by distilled water, and is dried in vacuum at 100 ℃ for 1h to constant weight, so that the polyurethane PU-16 is obtained.

Example 17

Fresh polybutylene adipate diol, polycaprolactone diol, bis (4-hydroxyphenyl) disulfide, dibutyltin dilaurate, and tetrahydrofuran were charged in a glove box charged with 99.999% Ar to a three-necked reactor equipped with a mechanical stirrer for a one-step reaction. Wherein [ polybutylene adipate diol + polycaprolactone diol ]/[ bis (4-hydroxyphenyl) disulfide ]/[ 1/99 (mass ratio), the molecular weights of the polybutylene adipate diol and the polycaprolactone diol are both 600g/mol, and the molar ratio of the polybutylene adipate diol to the polycaprolactone diol is 10: 1, dibutyltin dilaurate accounts for 0.1 wt% of the total mass of reactants, the molar ratio of hydroxyl groups to isocyanate groups is 0.5:1, the concentration of all reactants is 10 wt%, the reaction temperature is 25 ℃, the reaction time is 1h, finally, the polymer precipitate is washed for a plurality of times by distilled water, and vacuum drying is carried out at 60 ℃ for 48h to constant weight, so as to obtain the polyurethane PU-17.

Comparative example 1

Fresh polyhexamethylene adipate diol, [ bis (4-hydroxyphenyl) disulfide ]/[ bis (4-hydroxyphenyl) disulfide ] - [ 1/99 (mass ratio), ] molecular weights of the polytetramethylene adipate diol and polycaprolactone diol were 600g/mol, dibutyltin dilaurate was 0.1% by weight of the total mass of the reactants, the molar ratio of hydroxyl groups to isocyanate groups was 0.5:1, the concentrations of all reactants were 10% by weight, the reaction temperature was 25 ℃ and the reaction time was 1h, and finally the polymer precipitate was washed several times with distilled water and dried under vacuum at 60 ℃ for 12h to constant weight in a three-necked reactor equipped with a mechanical stirrer to conduct a one-step reaction, comparative polyurethanes were obtained.

And (3) performance characterization:

1. nuclear magnetic resonance (¹H-NMR)

At room temperature, the reaction was carried out at AVANCE III (400MHz) using tetramethylsilane as an internal standard¹H-NMR spectrum, sample concentration 1-5 wt%.

2. Self-healing performance

The self-healing test was performed as follows: the 0.4mm polyurethane film was cut into several small rectangular films, and the middle portions of the small rectangular films were completely cut off to perform a self-healing test. The recovery of the cut was observed under an optical microscope (Olympus/BX 51TF Instec H601, Japan) equipped with a hot stage.

As can be seen from FIGS. 4a to 4d, the polyurethane prepared by the embodiment of the invention can realize self-healing at normal temperature for 300 min.

3. Mechanical Properties

The mechanical properties of the samples were measured with a universal tester (UTM, Zwick Instruments, type: Z1.0) with the tensile rate maintained at 5 mm/min.

As can be seen from FIG. 9, the mechanical tensile properties of the polyurethanes prepared in examples 1 to 5 can be adjusted according to the different ratios of the soft segment to the hard segment, so as to meet the requirements of different fields.

As can be seen from fig. 11, the polyurethane prepared in comparative example 1 has mechanical properties not meeting the requirements of the electronic skin substrate, and is plastically deformed during the stretching process and cannot return to the original state.

4. Anti-aging performance

The artificial hernia was left in an aging chamber for 12 days, and the transparency of the polyurethane film was measured every four days using a UV-visible spectrophotometer (Lambda 950, Perkin-Elmer, USA) in the wavelength range of 380-800 nm.

As can be seen from FIG. 5, the light transmittance of the polyurethane prepared in the examples is 88.3%, the light transmittance of the polyurethane prepared in the examples after being placed for 4 days, 8 days and 12 days is 87.6%, 86.4% and 86.3%, respectively, and the light transmittance does not change greatly, which indicates that the polyurethane prepared by the invention has good aging resistance.

5. Controllable degradation performance

The polyurethane film prepared in example 1 was placed in alkali solutions of different pH values, and the mass loss and the change in molecular weight were observed for different degradation times.

As can be seen in fig. 6, in alkaline solutions with pH values less than 12, the mass loss is less than 10% over a degradation time of 8 days; however, in the alkaline solution with the pH value of 14, the mass loss reaches more than 50 percent in the degradation time of 8 days, which shows that the polyurethane prepared by the invention has good controllable degradation performance.

As can be seen from FIG. 7, in the alkaline solution with pH 14, the molecular weight thereof is continuously decreased and the molecular weight distribution thereof is gradually increased as the degradation time is continuously progressed, which indicates that the polyurethane prepared by the present invention is actually degraded in the alkaline solution with pH 14.

As can be seen from fig. 8, the comparative polyurethane prepared in comparative example 1, which had a change in mass loss of less than 5% when soaked in an alkaline solution having a pH of 14 for a period of 8 days, laterally illustrates the controlled degradation properties of the prepared polyurethane. The contrast sample changes the soft segment of polyurethane, and the poly (hexamethylene adipate) glycol replaces the polyester soft segment, so that other components are unchanged, the crystallinity is larger, and the degradation is not easy to occur.

As can be seen from FIG. 10, the enthalpy value of the comparative sample is large, the crystallinity of the comparative sample is 70% by calculation, so that the degradation performance of the comparative sample is influenced, and the crystallinity of the comparative sample is controlled by adjusting the molar ratio of polybutylene adipate diol to polycaprolactone diol, so that the purpose of controllable degradation is achieved.

In addition, the inventors of the present invention have also made experiments with reference to the above examples and by using other raw materials, process operations, and process conditions described in the present specification, and have obtained preferable results.

The aspects, embodiments, features and examples of the present invention should be considered as illustrative in all respects and not intended to be limiting of the invention, the scope of which is defined only by the claims. Other embodiments, modifications, and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed invention.

The use of headings and chapters in this disclosure is not meant to limit the disclosure; each section may apply to any aspect, embodiment, or feature of the disclosure.

Throughout this specification, where a composition is described as having, containing, or comprising specific components or where a process is described as having, containing, or comprising specific process steps, it is contemplated that the composition of the present teachings also consist essentially of, or consist of, the recited components, and the process of the present teachings also consist essentially of, or consist of, the recited process steps.

It should be understood that the order of steps or the order in which particular actions are performed is not critical, as long as the teachings of the present invention remain operable. Further, two or more steps or actions may be performed simultaneously.

While the invention has been described with reference to illustrative embodiments, it will be understood by those skilled in the art that various other changes, omissions and/or additions may be made and substantial equivalents may be substituted for elements thereof without departing from the spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated any use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another.