Organic-inorganic hybrid self-repairing polyurethane and preparation method thereof

Abstract

The invention relates to the technical field of preparation of functional polymer materials, in particular to organic-inorganic hybrid self-repairing polyurethane and a preparation method thereof, and the organic-inorganic hybrid self-repairing polyurethane comprises the following components in parts by weight: 20-40 parts of polytetrahydrofuran glycol; 10 to 20 parts of modified polytetrahydrofuran glycol; 1-5 parts of a hydrophilic chain extender; 20 to 45 parts of isophorone diisocyanate; 1-10 parts of a chain extender I; 2-10 parts of a chain extender II and the like. An organic-inorganic hybridization method is adopted, a polysiloxane structure is introduced into a polyurethane cross-linked network, a polysiloxane area and polyurethane polyol macromolecules are connected through covalent bonds through interface modification, and phase separation is effectively avoided; besides, a chain extender with polyfunctional groups is adopted to prepare waterborne polyurethane which has a cross-linked structure and contains dynamic covalent bonds and dynamic non-covalent bonds, the hybrid polyurethane material is finally cured to form an organic-inorganic hybrid cross-linked structure, and the organic-inorganic hybrid polyurethane material has the characteristics of high strength and high self-repairing performance; wide application prospects are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of functional polymer materials, and specifically relates to an organic-inorganic hybrid self-healing polyurethane and a preparation method thereof. Background Art

[0002] Self-healing polymer materials refer to a new type of polymer materials that can repair their own physical damages and restore physical properties, and usually achieve the self-healing function by introducing dynamic non-covalent bonds and dynamic covalent bonds into their molecular structures. Because it is superior to traditional polymer materials in many aspects such as improving the durability and safety of materials, reducing maintenance costs, expanding application fields, environmental protection and sustainability, etc., it has attracted wide attention.

[0003] However, while self-healing materials obtain self-healing properties, they often sacrifice a part of mechanical strength, and it is difficult to improve both mechanical strength and self-healing properties at the same time, which affects the application scope of self-healing materials. Summary of the Invention

[0004] In view of the above problems, an organic-inorganic hybrid self-healing polyurethane and a preparation method thereof are provided. Through this preparation method, the problem that the current self-healing polymers have low mechanical strength and it is difficult to obtain both high self-healing performance and high strength is solved.

[0005] To solve the problems of the prior art, the present invention provides an organic-inorganic hybrid self-healing polyurethane, which comprises the following components and their parts by weight: 20-40 parts of polytetrahydrofuran diol; 10-20 parts of modified polytetrahydrofuran diol, and the modified polytetrahydrofuran diol is prepared by reacting polytetrahydrofuran diol (Mn = 2000 g / mol), isocyanatopropyltrimethoxysilane and a phase transfer catalyst; 1-5 parts of a hydrophilic chain extender; 20-45 parts of isophorone diisocyanate; 1-10 parts of chain extender I; 2-10 parts of chain extender II; 10-25 parts of a polysiloxane precursor, and the polysiloxane precursor is prepared by reacting tetraethoxysilane, methyltriethoxysilane, ethanol, deionized water and hydrochloric acid solution; 80-120 parts of deionized water, the chain extender I is 2,4-diamino-6-hydroxypyrimidine (DAHP), and the chain extender II is 4,4'-dithiobisbenzenamine (2S).

[0006] Preferably, the preparation method of the self-healing polyurethane comprises the following steps: (1) By weight, 40-50 parts of tetraethoxysilane, 35-45 parts of ethanol, and 7-10 parts of methyltriethoxysilane are added to a beaker and magnetically stirred at a speed of 200 rpm for 10-60 minutes at a certain temperature. After 5-10 parts of deionized water and 0.1-1 part of a hydrochloric acid solution with a certain concentration are uniformly mixed, they are added to the above beaker and stirred for 12-24 hours at a certain temperature. Then, the above solution is rotary evaporated at 80 °C, 400 mbar, and 50 rpm to remove part of the solvent until the mass of the final product is 20-35% of the mass of the initial raw materials, and a polysiloxane precursor is prepared: (2) By weight, 30-50 parts of polytetrahydrofuran diol (Mn = 2000 g / mol) are taken, 2-8 parts of isocyanatopropyltrimethoxysilane are added, and 1-3 parts of a phase transfer catalyst are added. After mechanical stirring at 200-400 rpm for 30 minutes at a certain temperature, a modified polytetrahydrofuran diol is prepared; (3) By weight, the polytetrahydrofuran diol is dried under reduced pressure at 150 °C and -0.1 MPa for 2 hours. 20-40 parts of dried polytetrahydrofuran diol, 10-20 parts of the modified polytetrahydrofuran diol, and 1-5 parts of a hydrophilic chain extender are added to a four-necked flask equipped with a dropping funnel, a reflux condenser, and a stirrer, and nitrogen is introduced for protection. The temperature is raised to 80 °C, and mechanical stirring is carried out at 400 rpm for 3 hours. 20-45 parts of isophorone diisocyanate are slowly added dropwise with a dropping funnel to obtain an NCO-terminated prepolymer. After the reaction temperature is lowered to 60 °C, 1-10 parts of chain extender I and 2-10 parts of chain extender II are added, and stirring is continued for 30 minutes. The reaction temperature is lowered to 40 °C, 10-25 parts of the polysiloxane precursor are added, and stirring is continued at 800 rpm for 30 minutes. The reaction temperature is lowered to room temperature, 80-120 parts of deionized water are added dropwise with a dropping funnel, and rapid stirring is carried out at 1000 rpm for 1 hour to obtain an organic-inorganic hybrid self-healing aqueous polyurethane emulsion; (4) The organic-inorganic hybrid self-healing aqueous polyurethane emulsion is poured into a polytetrafluoroethylene mold, placed at 25 °C for 1 week, and then placed in an 80 °C oven for drying for 2-3 hours to obtain an organic-inorganic hybrid self-healing polyurethane material.

[0007] Preferably, in the step (1), the stirring temperature is room temperature, and the concentration of hydrochloric acid is 2 mol / L.

[0008] Preferably, in the step (2), the phase transfer catalyst is potassium acetate, and the reaction temperature is room temperature.

[0009] Preferably, in the step (3), the hydrophilic chain extender is one of dimethylolbutyric acid or dimethylolpropionic acid.

[0010] The beneficial effects of the present invention compared with the prior art are:

[0011] 1. The present invention adopts an organic-inorganic hybridization method to introduce a polysiloxane structure into the polyurethane crosslinking network. Through interface modification, the polysiloxane region and the polyurethane polyol macromolecules are connected by covalent bonds, effectively avoiding phase separation. In addition, a chain extender with multiple functional groups is used to prepare a waterborne polyurethane with a crosslinked structure containing dynamic covalent bonds and dynamic non-covalent bonds. After the hybrid polyurethane material is finally cured, an organic-inorganic hybrid crosslinked structure is formed. This organic-inorganic hybrid polyurethane material has the characteristics of high strength and high self-healing performance and has broad application prospects.

[0012] 2. The polysiloxane precursor prepared by the method of the present invention has a large number of hydroxyl groups (-OH), which can react with the isocyanate groups (-NCO) in the polyurethane prepolymer to form strong interfacial interactions. A small amount of solvent in the system mainly acts on the silanol groups (-SiOH) and is bound between the molecular chains by methyl groups and cannot react with the isocyanate groups.

[0013] 3. 2,4-Diamino-6-hydroxypyrimidine in the present invention contains three functional groups and can react with isocyanate groups to form a high-strength polyurethane molecular chain with a crosslinked structure. Moreover, multiple hydrogen bonds are easily formed between the molecular chains to provide self-healing performance; the chain extender 4,4'-dithiobisbenzeneamine contains dynamic disulfide bonds and provides strong self-healing performance.

[0014] 4. The siloxane on the modified polytetrahydrofuran diol in the present invention hydrolyzes to form a silanol structure. During the curing and molding process of the organic-inorganic hybrid polyurethane, it undergoes polycondensation with the silanol on the polysiloxane precursor to form a Si-O-Si structure and is connected to the main chain of the polyurethane molecule, further enhancing the interfacial interaction between the organic and inorganic phases and improving the strength of the material. Description of the Drawings

[0015] Figure 1 is a reaction schematic diagram of the modified polytetrahydrofuran diol in Example 2 of an organic-inorganic hybrid self-healing polyurethane and its preparation method.

[0016] Figure 2 is the infrared spectrum (FTIR-ATR) of the modified polytetrahydrofuran diol in Example 2 of an organic-inorganic hybrid self-healing polyurethane and its preparation method at different reaction times.

[0017] Figure 3 is the optical microscope photos of the self-healing polyurethane in Comparative Example 1 and the organic-inorganic hybrid self-healing polyurethane in Example 2 of an organic-inorganic hybrid self-healing polyurethane and its preparation method before and 24 hours after scratch repair.

[0018] Figure 4 is the structural schematic diagram of the organic-inorganic hybrid self-healing polyurethane in Example 2 of an organic-inorganic hybrid self-healing polyurethane and its preparation method. Detailed implementation mode

[0019] To further understand the features, technical means, specific purposes and functions achieved by the present invention, the present invention will be described in further detail below in conjunction with the accompanying drawings and specific implementation modes.

[0020] An organic-inorganic hybrid self-healing polyurethane, comprising the following components and their parts by weight: 20-40 parts of polytetrahydrofuran diol; 10-20 parts of modified polytetrahydrofuran diol, and the modified polytetrahydrofuran diol is prepared by reacting polytetrahydrofuran diol (Mn = 2000 g / mol), isocyanatopropyltrimethoxysilane and a phase transfer catalyst; 1-5 parts of a hydrophilic chain extender; 20-45 parts of isophorone diisocyanate; 1-10 parts of chain extender I; 2-10 parts of chain extender II; 10-25 parts of a polysiloxane precursor, and the polysiloxane precursor is prepared by reacting tetraethoxysilane, methyltriethoxysilane, ethanol, deionized water and a hydrochloric acid solution; 80-120 parts of deionized water.

[0021] The chain extender I is 2,4-diamino-6-hydroxypyrimidine (DAHP), and the chain extender II is 4,4-dithiobis(aniline) (2S).

[0022] The preparation method of the self-healing polyurethane comprises the following steps:

[0023] (1) According to parts by weight, add 40-50 parts of tetraethoxysilane, 35-45 parts of ethanol, and 7-10 parts of methyltriethoxysilane to a beaker, magnetically stir at a speed of 200 rpm for 10-60 minutes at a certain temperature, uniformly mix 5-10 parts of deionized water and 0.1-1 part of a hydrochloric acid solution with a certain concentration and add them to the above beaker, stir at a certain temperature for 12-24 hours, and then rotate and evaporate part of the solvent from the above solution at 80 °C, 400 mbar, and 50 rpm until the mass of the final product is 20-35% of the mass of the initial raw materials, to prepare a polysiloxane precursor;

[0024] (2) According to parts by weight, take 30-50 parts of polytetrahydrofuran diol (Mn = 2000 g / mol), add 2-8 parts of isocyanatopropyltrimethoxysilane, add 1-3 parts of a phase transfer catalyst, and mechanically stir at a speed of 200-400 rpm for 30 minutes to obtain modified polytetrahydrofuran diol;

[0025] (3) Weighing by parts by weight, poly(tetramethylene ether) glycol is dried under reduced pressure at 150 °C and -0.1 MPa for 2 hours. Take 20 - 40 parts by weight of the dried poly(tetramethylene ether) glycol, 10 - 20 parts by weight of the modified poly(tetramethylene ether) glycol, and 1 - 5 parts by weight of a hydrophilic chain extender and add them to a four-necked flask equipped with a dropping funnel, a reflux condenser, and a stirrer. Then introduce nitrogen for protection, heat up to 80 °C, and mechanically stir at 400 rpm for 3 hours. Slowly add 20 - 45 parts by weight of isophorone diisocyanate using the dropping funnel to obtain an NCO-terminated prepolymer. After lowering the reaction temperature to 60 °C, add 1 - 10 parts by weight of chain extender I and 2 - 10 parts by weight of chain extender II, and continue stirring and reacting for 30 minutes. Then lower the reaction temperature to 40 °C, add 10 - 25 parts by weight of the polysiloxane precursor, and continue stirring at 800 rpm for 30 minutes. After lowering the reaction temperature to room temperature, use the dropping funnel to add 80 - 120 parts by weight of deionized water, and rapidly stir at 1000 rpm for 1 hour to obtain an organic-inorganic hybrid self-healing aqueous polyurethane emulsion;

[0026] (4) Pour the organic-inorganic hybrid self-healing aqueous polyurethane emulsion into a polytetrafluoroethylene mold, let it stand at 25 °C for 1 week, and then place it in an 80 °C oven to dry for 2 - 3 hours to obtain an organic-inorganic hybrid self-healing polyurethane material.

[0027] In the step (1), the stirring temperature is room temperature, and the concentration of hydrochloric acid is 2 mol / L.

[0028] In the step (2), the phase transfer catalyst is potassium acetate, and the reaction temperature is room temperature.

[0029] In the step (3), the hydrophilic chain extender is one of dimethylolbutyric acid or dimethylolpropionic acid.

[0030] Example 1: (1) Preparation of polysiloxane precursor: Weighing by parts by weight, add 40 parts of tetraethoxysilane, 35 parts of ethanol, and 7 parts of methyltriethoxysilane to a beaker, magnetically stir at a speed of 200 rpm at room temperature for 10 minutes. After uniformly mixing 5 parts of deionized water and 0.1 part of 2 mol / L hydrochloric acid solution, add them to the above beaker, stir at room temperature for 12 hours, and then rotate and evaporate part of the solvent of the above solution at 80 °C, 400 mbar, and 50 rpm until the mass of the final product is 20% of the mass of the initial raw materials.

[0031] (2) Modification of polyether polyol: Weighing by parts by weight, take 30 parts of poly(tetramethylene ether) glycol (Mn = 2000 g / mol), add 2 parts of isocyanatopropyltrimethoxysilane, add 1 part of the phase transfer catalyst potassium acetate, and mechanically stir at 200 rpm at room temperature for 30 minutes to obtain modified poly(tetramethylene ether) glycol.

[0032] (3) Preparation of organic-inorganic hybrid self-healing aqueous polyurethane emulsion: By weight, polytetrahydrofuran diol was dried under reduced pressure at 150 °C and -0.1 MPa for 2 hours. 20 parts of dried polytetrahydrofuran diol, 10 parts of modified polytetrahydrofuran diol, and 1 part of dimethylolbutyric acid were added to a four-necked flask equipped with a dropping funnel, a reflux condenser, and a stirrer, and nitrogen was introduced for protection. The temperature was raised to 80 °C, and mechanical stirring was carried out at 400 rpm for 3 hours. 20 parts of isophorone diisocyanate were slowly added dropwise using a dropping funnel to obtain an NCO-terminated prepolymer. After the reaction temperature was lowered to 60 °C, 1 part of 2,4-diamino-6-hydroxypyrimidine and 2 parts of 4,4-dithiobisbenzenamine were added, and the stirring reaction was continued for 30 minutes. The reaction temperature was lowered to 40 °C, 10 parts of polysiloxane precursor were added, and stirring was continued at 800 rpm for 30 minutes. Then the reaction temperature was lowered to room temperature, and 80 parts of deionized water were added dropwise using a dropping funnel. After rapid stirring at 1000 rpm for 1 hour, an organic-inorganic hybrid self-healing aqueous polyurethane emulsion was prepared.

[0033] (4) The prepared organic-inorganic hybrid self-healing aqueous polyurethane emulsion was poured into a polytetrafluoroethylene mold, placed at 25 °C for 1 week, and then dried in an 80 °C oven for 2 hours to obtain an organic-inorganic hybrid self-healing polyurethane material.

[0034] Example 2: (1) Preparation of polysiloxane precursor: By weight, 45 parts of tetraethoxysilane, 40 parts of ethanol, and 7 parts of methyltriethoxysilane were added to a beaker, and magnetic stirring was carried out at a speed of 200 rpm at room temperature for 30 minutes. 8 parts of deionized water and 0.5 part of 2 mol / L hydrochloric acid solution were uniformly mixed and then added to the above beaker. Stirring was carried out at room temperature for 18 hours, and then the above solution was rotary evaporated to remove part of the solvent at 80 °C, 400 mbar, and 50 rpm until the mass of the final product was 25% of the mass of the initial raw materials.

[0035] (2) Modification of polyether polyol: By weight, 40 parts of polytetrahydrofuran diol (Mn = 2000 g / mol) were taken, 6 parts of isocyanatopropyltrimethoxysilane were added, and 2 parts of phase transfer catalyst potassium acetate were added. After mechanical stirring at 300 rpm at room temperature for 30 minutes, modified polytetrahydrofuran diol was prepared.

[0036] (3) Preparation of organic-inorganic hybrid self-healing aqueous polyurethane emulsion: By weight, polytetrahydrofuran diol was dried under reduced pressure at 150 °C and -0.1 MPa for 2 hours. 30 parts of dried polytetrahydrofuran diol, 15 parts of modified polytetrahydrofuran diol, and 3 parts of dimethylolbutyric acid were added to a four-necked flask equipped with a dropping funnel, a reflux condenser, and a stirrer, and nitrogen was introduced for protection. The temperature was raised to 80 °C, and mechanical stirring was carried out at 400 rpm for 3 hours. 30 parts of isophorone diisocyanate were slowly added dropwise using a dropping funnel to obtain an NCO-terminated prepolymer. After the reaction temperature was lowered to 60 °C, 5 parts of 2,4-diamino-6-hydroxypyrimidine and 5 parts of 4,4-dithiobisbenzenamine were added, and the stirring reaction was continued for 30 minutes. The reaction temperature was lowered to 40 °C, 20 parts of polysiloxane precursor were added, and stirring was continued at 800 rpm for 30 minutes. Then the reaction temperature was lowered to room temperature, 100 parts of deionized water were added dropwise using a dropping funnel, and rapid stirring was carried out at 1000 rpm for 1 hour to obtain the organic-inorganic hybrid self-healing aqueous polyurethane emulsion.

[0037] (4) The prepared organic-inorganic hybrid self-healing aqueous polyurethane emulsion was poured into a polytetrafluoroethylene mold, placed at 25 °C for 1 week, and then dried in an 80 °C oven for 2.5 hours to obtain the organic-inorganic hybrid self-healing polyurethane material.

[0038] Example 3: (1) Preparation of polysiloxane precursor: By weight, 50 parts of tetraethoxysilane, 45 parts of ethanol, and 10 parts of methyltriethoxysilane were added to a beaker, and magnetic stirring was carried out at a speed of 200 rpm at room temperature for 60 minutes. 10 parts of deionized water and 1 part of 2 mol / L hydrochloric acid solution were uniformly mixed and then added to the above beaker, and stirring was carried out at room temperature for 24 hours. Then the above solution was rotary evaporated at 80 °C, 400 mbar, and 50 rpm to remove part of the solvent until the mass of the final product was 35% of the mass of the initial raw materials.

[0039] (2) Modification of polyether polyol: By weight, 50 parts of polytetrahydrofuran diol (Mn = 2000 g / mol) were taken, 8 parts of isocyanatopropyltrimethoxysilane were added, and 3 parts of phase transfer catalyst potassium acetate were added. Mechanical stirring was carried out at 400 rpm at room temperature for 30 minutes to obtain the modified polytetrahydrofuran diol.

[0040] (3) Preparation of organic-inorganic hybrid self-healing aqueous polyurethane emulsion: By weight, polytetrahydrofuran diol was dried under reduced pressure at 150 °C and -0.1 MPa for 2 hours. 40 parts of dried polytetrahydrofuran diol, 20 parts of modified polytetrahydrofuran diol, and 5 parts of dimethylolpropionic acid were added to a four-necked flask equipped with a dropping funnel, a reflux condenser, and a stirrer, and nitrogen was introduced for protection. The temperature was raised to 80 °C, and mechanical stirring was carried out at 400 rpm for 3 hours. 45 parts of isophorone diisocyanate were slowly added dropwise using a dropping funnel to obtain an NCO-terminated prepolymer. After the reaction temperature was lowered to 60 °C, 10 parts of 2,4-diamino-6-hydroxypyrimidine and 10 parts of 4,4-dithiobenzidine were added, and stirring was continued for 30 minutes. The reaction temperature was lowered to 40 °C, 25 parts of polysiloxane precursor were added, and stirring was continued at 800 rpm for 30 minutes. Then the reaction temperature was lowered to room temperature, and 120 parts of deionized water were added dropwise using a dropping funnel. After rapid stirring at 1000 rpm for 1 hour, an organic-inorganic hybrid self-healing aqueous polyurethane emulsion was prepared.

[0041] (4) The prepared organic-inorganic hybrid self-healing aqueous polyurethane emulsion was poured into a polytetrafluoroethylene mold, left at 25 °C for 1 week, and then placed in an 80 °C oven for drying for 3 hours to obtain an organic-inorganic hybrid self-healing polyurethane material.

[0042] Comparative Example 1: Preparation of self-healing aqueous polyurethane emulsion: By weight, polytetrahydrofuran diol was dried under reduced pressure at 150 °C and -0.1 MPa for 2 hours. 45 parts of dried polytetrahydrofuran diol and 3 parts of dimethylolbutyric acid were added to a four-necked flask equipped with a dropping funnel, a reflux condenser, and a stirrer, and nitrogen was introduced for protection. The temperature was raised to 80 °C, and mechanical stirring was carried out at 400 rpm for 3 hours. 30 parts of isophorone diisocyanate were slowly added dropwise using a dropping funnel to obtain an NCO-terminated prepolymer. After the reaction temperature was lowered to 60 °C, 5 parts of 2,4-diamino-6-hydroxypyrimidine and 5 parts of 4,4-dithiobenzidine were added, and stirring was continued for 30 minutes. The reaction temperature was lowered to 40 °C, 3 parts of triethylamine were added, and stirring was continued at 400 rpm for 30 minutes. Then the reaction temperature was lowered to room temperature, and 100 parts of deionized water were added dropwise using a dropping funnel. After rapid stirring at 1000 rpm for 1 hour, a self-healing aqueous polyurethane emulsion was prepared.

[0043] (4) The prepared organic-inorganic hybrid self-healing aqueous polyurethane emulsion was poured into a polytetrafluoroethylene mold, left at 25 °C for 1 week, and then placed in an 80 °C oven for drying for 2.5 hours to obtain an organic-inorganic hybrid self-healing polyurethane material.

[0044] To verify the self-healing performance and mechanical properties of the prepared organic-inorganic hybrid self-healing polyurethane, the following tests were conducted:

[0045] (1) Tensile strength test: Using a CMT4040 electronic universal material testing machine, the prepared specimens were conditioned at standard laboratory temperature for 3 h according to GB2941-91 (humidity not required), and the width and thickness of each specimen were measured. Subsequently, the tensile strength and elongation at break of the specimens were measured at a tensile speed of 100 mm / min. Five sets of data were measured for each group of specimens, and the results were averaged.

[0046] (2) Self-healing performance test: First, a scratch was made on the surface of the polyurethane film with a scalpel, and its morphology was observed and recorded using a Primotech metallurgical microscope. Then, it was placed in an 80 °C oven for 24 h. After taking it out, the change in the scratch morphology was observed again using the Primotech metallurgical microscope and compared with the initial morphology of the scratch.

[0047] To more quantitatively evaluate the self-healing efficiency of polyurethane, a dumbbell-shaped specimen was cut with a scalpel, and the two cut surfaces were immediately brought into contact. Then, it was placed in an 80 °C oven for 24 h for self-healing treatment. The self-healing efficiency was calculated using the ratio of the tensile strength after repair to that of the original sample, i.e.:

[0048] Self-healing efficiency (%) = [σself-healing / σinitial] × 100%

[0049] Refer to Figure 1 - Figure 2 It can be seen that as the reaction time increases, the isocyanate group concentration of isocyanatopropyltrimethoxysilane gradually decreases until it disappears after 30 minutes, indicating that isocyanatopropyltrimethoxysilane reacts completely with polytetrahydrofuran diol after 30 minutes.

[0050] Figure 3 Optical microscope photos of the scratch on the self-healing polyurethane of Comparative Example 1 and the organic-inorganic hybrid self-healing polyurethane prepared in Example 2 before (a) and (b) and after 24 h of scratch repair (a1) and (b1); (a): Comparative Example 1, before repair; (b): Example 2, before repair; (a1): Comparative Example 1, after 24 h of repair; (b1): Example 2, after 24 h of repair; It can be seen from the figure that after 24 h, the organic-inorganic hybrid self-healing polyurethane has a self-healing effect similar to that of the self-healing polyurethane, and the scratch basically disappears.

[0051] The tensile strength and self-healing efficiency of the organic-inorganic hybrid self-healing polyurethanes of Examples 1-3 and the self-healing polyurethane of Comparative Example 1 before and after self-healing are shown in Table 1 as follows;

[0052] Table 1:

[0053]

[0054] As can be seen from the data in Table 1 above, the tensile strength of the organic-inorganic hybrid self-healing polyurethane in Examples 1-3 is much higher than that of the self-healing polyurethane in Comparative Example 1, while the self-healing efficiency after 24 hours at 80 °C is similar to that of the self-healing polyurethane in Comparative Example 1, both reaching over 98%.

[0055] The above embodiments only represent one or several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. An organic-inorganic hybrid self-repairing polyurethane, characterized in that: The invention comprises the following components and their weight proportions: 20-40 parts of polytetrahydrofuran diol; 10-20 parts of modified polytetrahydrofuran diol, wherein the modified polytetrahydrofuran diol is prepared by reacting polytetrahydrofuran diol (Mn=2000 g / mol), isocyanate propyltrimethoxysilane and a phase transfer catalyst; 1-5 parts of a hydrophilic chain extender; 20-45 parts of isophorone diisocyanate; and 1-10 parts of a chain extender I; 2-10 parts of chain extender II; 10-25 parts of polysiloxane precursor, wherein the polysiloxane precursor is prepared by reacting tetraethoxysilane, methyltriethoxysilane, ethanol, deionized water and hydrochloric acid solution; 80-120 parts of deionized water.

2. The organic-inorganic hybrid self-healing polyurethane according to claim 1, characterized in that: The chain extender I is 2,4-diamino-6-hydroxypyrimidine (DAHP), and the chain extender II is 4,4-dithiodiphenylamine (2S).

3. A method for preparing an organic-inorganic hybrid self-repairing polyurethane, characterized in that: The preparation method of the self-repairing polyurethane comprises the following steps: (1) According to the weight ratio, 40-50 parts of tetraethoxysilane, 35-45 parts of ethanol, and 7-10 parts of methyltriethoxysilane are added to a beaker, and the mixture is magnetically stirred at a speed of 200 rpm for 10-60 minutes at a certain temperature. 5-10 parts of deionized water and 0.1-1 part of a hydrochloric acid solution of a certain concentration are uniformly mixed and added to the above beaker, and stirred at a certain temperature for 12-24 hours. Then, the above solution is rotary evaporated at 80° C., 400 mbar, and 50 rpm to remove part of the solvent until the mass of the final product is 20-35% of the mass of the initial raw material, thereby preparing a polysiloxane precursor; (2) according to the weight ratio, 30-50 parts of polytetrahydrofuran diol (Mn=2000g / mol) are taken, 2-8 parts of isocyanate propyl trimethoxy silane are added, 1-3 parts of phase transfer catalyst are added, and the modified polytetrahydrofuran diol is prepared after mechanical stirring at 200-400rpm for 30 minutes at a certain temperature; (3) according to parts by weight, polytetrahydrofuran diol was carried out under reduced pressure drying at 150 ℃,-0.1MPa for 2 hours, 20-40 parts of dry polytetrahydrofuran diol, 10-20 parts of described modified polytetrahydrofuran diol, 1-5 parts of hydrophilic chain extender were taken and joined in a four-hole boiling flask with dropping funnel, reflux condensing tube and agitator, and nitrogen protection was passed, and the mixture was warming up to 80 ℃, and mechanically stirred at 400rpm for 3 hours, and 20-45 parts of isophorone diisocyanate were slowly dripped with a dropping funnel, Obtain an NCO-terminated prepolymer, lower the reaction temperature to 60°C, add 1-10 parts of chain extender I and 2-10 parts of chain extender II, continue stirring and reacting for 30 minutes, lower the reaction temperature to 40°C, add 10-25 parts of the polysiloxane precursor, continue stirring at 800 rpm for 30 minutes, lower the reaction temperature to room temperature, use a dropping funnel to drop 80-120 parts of deionized water, and quickly stir at 1000 rpm for 1 hour to obtain an organic-inorganic hybrid self-repairing waterborne polyurethane emulsion; (4) pouring the organic-inorganic hybrid self-healing water-based polyurethane emulsion into a polytetrafluoroethylene mold, placing it at 25° C. for 1 week, and then drying it in an oven at 80° C. for 2-3 hours to obtain an organic-inorganic hybrid self-healing polyurethane material.

4. The organic-inorganic hybrid self-healing polyurethane and the preparation method thereof according to claim 3, characterized in that: The stirring temperature in step (1) is room temperature, and the concentration of hydrochloric acid is 2 mol / L.

5. The organic-inorganic hybrid self-healing polyurethane and the preparation method thereof according to claim 3, characterized in that: In the step (2), the phase transfer catalyst is potassium acetate and the reaction temperature is room temperature.

6. The organic-inorganic hybrid self-healing polyurethane and the preparation method thereof according to claim 3, characterized in that: In the step (3), the hydrophilic chain extender is one of dihydroxymethyl butyric acid and dimethyl propionic acid.

Images