Polydopamine nano-microsphere reinforced bionic composite material and preparation method thereof

Abstract

The preparation method comprises the following steps: step 1, drying polytetrahydrofuran for later use, mixing isophorone diisocyanate and dibutyltin dilaurate in an organic solvent, then adding the mixture into the dried polytetrahydrofuran, and carrying out ultrasonic treatment to obtain a polydopamine nanoparticle-reinforced bionic composite material; reacting in a nitrogen protection atmosphere to prepare a prepolymer; 2, dissolving 4, 4 '-dithiodiphenylamine in an organic solvent, adding the obtained solution into the prepolymer, and carrying out heat preservation at 70 DEG C for 3 h for a reaction so as to obtain a polyurethane solution; and 3, dissolving the polydopamine nano-microspheres in an organic solvent, adding the solution into a polyurethane solution, uniformly mixing, and carrying out curing molding treatment. According to the bionic self-repairing polyurethane material, the mechanical property can be enhanced on the premise that the self-repairing capacity is not obviously sacrificed, the tensile strength is 31.8 MPa, the elongation at break is 1220%, the performance is greatly improved, and the bionic self-repairing polyurethane material has wide application prospects in the fields of solid propellants, flexible electronics, high-end coatings and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer nanocomposites, in particular to a kind of polydopamine nanospheres reinforced biomimetic composite material and preparation method thereof. BACKGROUND

[0002] Self-healing polyurethane material can imitate the wound healing process of organism, and realizes self-repairing through the reversible reaction of dynamic chemical bonds such as disulfide bond and hydrogen bond in molecular structure after being damaged, thereby prolonging the service life of the material and improving the safety, and has broad prospects in solid propellant, flexible electronics, high-end coating and other fields. However, the introduction of dynamic bond not only endows the material with self-repairing ability, but also weakens the stability of high polymer network, resulting in generally low intrinsic mechanical strength such as tensile strength. At present, most self-repairing materials are faced with the inherent contradiction between self-repairing ability and mechanical properties, and the material with high repair efficiency usually exhibits low mechanical strength, while high mechanical strength will inhibit chain segment movement and lead to repair difficulty. The above difficulties seriously restrict the practical engineering application of self-repairing material.

[0003] To solve the above problems, the research direction of those skilled in the art has been turned to the field of biomimetics. The nacre in nature realizes the perfect balance between strength and toughness with its unique "brick-mud" structure. The core lies in the synergistic effect realized by the strong interfacial interaction between rigid aragonite platelets ("brick") and flexible proteins ("mud"). Inspired by this, a kind of nanometer "brick" material capable of producing strong interfacial bonding with self-repairing polyurethane matrix is selected, which can significantly improve the mechanical properties of self-repairing polyurethane material. Polydopamine material contains rich phenolic hydroxyl and amino functional groups, and has super adhesion and activity. By making it into nanospheres, it can be used as an ideal rigid "brick" phase, and its surface functional groups can form strong hydrogen bonds and other interactions with the polyurethane matrix to realize excellent interfacial bonding and stress transfer, which is expected to enhance the mechanical properties of self-repairing polyurethane material. SUMMARY

[0004] The present application aims to overcome the defects of poor mechanical properties of existing self-repairing polyurethane materials, and provides a kind of polydopamine nanospheres reinforced biomimetic composite material with good self-repairing efficiency and excellent mechanical strength.

[0005] To achieve the above purpose, the technical solution provided by the present application is as follows: A preparation method of a kind of polydopamine nanospheres reinforced biomimetic composite material, comprising the following steps: Step one: dry polytetrahydrofuran for standby, mix isophorone diisocyanate and dibutyltin dilaurate in organic solvent, then add to the dried polytetrahydrofuran, and prepare a prepolymer in a nitrogen protective atmosphere; Step 2: Dissolve 4,4'-dithiodiphenylamine in an organic solvent, add it to the prepolymer, and react at 70°C for 3 hours to obtain a polyurethane solution; Step 3: Dissolve polydopamine nanospheres in an organic solvent, add them to a polyurethane solution, mix thoroughly, and then cure and mold them to obtain the final product.

[0006] Optionally, in step one, the molar ratio of polytetrahydrofuran, isophorone diisocyanate, and dibutyltin dilaurate is 1:2:0.01.

[0007] Optionally, in step two, the molar ratio of the prepolymer to 4,4'-dithiodiphenylamine is 1:1.

[0008] Optionally, the organic solvent is tetrahydrofuran or N,N-dimethylformamide.

[0009] Optionally, the preparation of the polydopamine nanospheres includes: Dopamine hydrochloride was dissolved in Tirs-HCl buffer and stirred at room temperature for 6 hours. After centrifugation, washing and drying, polydopamine nanospheres were obtained. The concentration of the Tirs-HCl buffer solution is 0.01 M, and the pH value is 8.5.

[0010] Optionally, the particle size range of the polydopamine nanospheres is 100–200 nm; The mass percentage of polydopamine nanospheres to polyurethane is 0.1–5 wt%.

[0011] Optionally, the polytetrahydrofuran has a number-average molecular weight of 2000.

[0012] Optionally, the drying of the polytetrahydrofuran includes: vacuum dehydration at 100°C for 2 hours, followed by cooling to 70°C; In step one, the reaction is carried out in a nitrogen protective atmosphere for 3 hours.

[0013] A biomimetic composite material reinforced with polydopamine nanospheres is prepared by any of the preparation methods of the biomimetic composite material reinforced with polydopamine nanospheres described in this invention.

[0014] The biomimetic composite material reinforced with polydopamine nanospheres described in this invention is used in the preparation of solid propellant binders.

[0015] Advantages of this invention: This invention is based on the biomimetic concept of the "brick-and-mortar" structure of mother-of-pearl. It innovatively selects polydopamine nanospheres as the rigid reinforcing phase ("brick") and introduces them into a self-healing polyurethane matrix ("mortar") containing dynamic bonds. The polydopamine microspheres not only provide rigid support, but their abundant functional groups on the surface can also form strong interfacial interactions with the polyurethane molecular chains, thereby enhancing mechanical properties without significantly sacrificing self-healing capabilities. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a synthesis roadmap for biomimetic self-healing polyurethane materials reinforced with polydopamine nanospheres; Figure 2 This is a transmission electron microscope image of polydopamine nanospheres; Figure 3 This is a stress-strain test diagram of a biomimetic self-healing polyurethane material reinforced with polydopamine nanospheres. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the invention are still within the scope of protection of the present invention.

[0018] This invention provides a general biomimetic strategy for introducing polydopamine nanospheres as a reinforcing phase to improve the mechanical properties of self-healing polyurethane nanocomposites and their preparation method. The method includes the following steps: Step 1: After drying polytetrahydrofuran, isophorone diisocyanate and dibutyltin dilaurate are mixed in an organic solvent and added to the dried polytetrahydrofuran. The reaction is carried out under a nitrogen protective atmosphere to prepare a prepolymer; Step 2: 4,4'-dithiodiphenylamine is dissolved in an organic solvent and added to the prepolymer. The reaction is carried out at 70°C for 3 hours to obtain a polyurethane solution; Step 3: Polydopamine nanospheres are dissolved in an organic solvent and added to the polyurethane solution. After mixing evenly, the mixture is cured and molded to obtain the final product. This biomimetic self-healing polyurethane material can enhance mechanical properties without significantly sacrificing self-healing ability, with a tensile strength of 31.8 MPa and an elongation at break of 1220%. Compared with the control group without polydopamine nanospheres (tensile strength 7.0 MPa, elongation at break 1757%), the performance is significantly improved, and it has broad application prospects in solid propellants, flexible electronics, high-end coatings and other fields.

[0019] CombinationFigure 1 The specific preparation steps include: Step 1: Dissolve dopamine hydrochloride in Tirs-HCl buffer, stir at room temperature for 6 hours, and obtain polydopamine nanospheres by centrifugation, washing and drying.

[0020] Step 2: Dehydrate polytetrahydrofuran under vacuum at 100°C for 2 hours, cool to 70°C, mix isophorone diisocyanate and dibutyltin dilaurate catalyst in an organic solvent, add to the dried polytetrahydrofuran, and react in a nitrogen atmosphere for 3 hours to prepare the prepolymer.

[0021] Step 3: Mix 4,4'-dithiodiphenylamine in an organic solvent, add it to the prepolymer solution, heat to 70°C and keep warm for 3 hours to react, and obtain a polyurethane solution.

[0022] Step 4: Dissolve the polydopamine nanospheres in an organic solvent, add them to a polyurethane solution, mix thoroughly, and then cure and mold to obtain the biomimetic self-healing polyurethane material reinforced with polydopamine nanospheres.

[0023] In step one, the concentration of the Tirs-HCl buffer is 0.01M and the pH value is 8.5.

[0024] In step two, the number-average molecular weight of polytetrahydrofuran is 2000.

[0025] In step two, the molar ratio between polytetrahydrofuran, isophorone diisocyanate and dibutyltin dilaurate is 1:2:0.01.

[0026] In step three, the molar ratio of the prepolymer to 4,4'-dithiodiphenylamine is 1:1.

[0027] In step four, the mass percentage of polydopamine nanospheres to polyurethane is 0.1–5 wt%.

[0028] The organic solvent used in the preparation step is tetrahydrofuran or N,N-dimethylformamide, and the particle size range of the polydopamine nanospheres is 100–200 nm.

[0029] Example 1: This embodiment provides a biomimetic self-healing polyurethane material reinforced with polydopamine nanospheres, combined with... Figure 1 As shown, the preparation steps include: Step 1: Dissolve 1g of dopamine hydrochloride in 200 mL of Tirs-HCl 8.5 buffer solution, stir at room temperature for 6 hours, and obtain polydopamine nanospheres by centrifugation, washing and drying.

[0030] Step 2: In a 100 mL three-necked flask equipped with a mechanical stirrer, thermometer, and reflux device, 20 g (10 mmol) of polytetrahydrofuran was dehydrated under vacuum at 100 °C for 2 h, and then cooled to 70 °C. 4.4 g (20 mmol) of isophorone diisocyanate and 0.06 g (0.1 mmol) of dibutyltin dilaurate catalyst were mixed in 40 mL of N,N-dimethylformamide and added to the dried polytetrahydrofuran. The mixture was reacted under a nitrogen atmosphere for 3 h to prepare the prepolymer.

[0031] Step 3: Mix 2.5g (10mmol) of 4,4'-dithiodiphenylamine in 10mL of N,N-dimethylformamide, add it to the prepolymer solution, heat to 70℃ and keep warm for 3h to react and obtain a polyurethane solution.

[0032] Step 4: Disperse 135 mg of polydopamine nanospheres in N,N-dimethylformamide and add them to a polyurethane solution (the mass fraction of polydopamine nanospheres is 0.5 wt%). After mixing evenly, place the solution in a vacuum oven and heat at 90°C for 24 hours for curing and molding to obtain the biomimetic self-healing polyurethane material reinforced with polydopamine nanospheres.

[0033] Taking Example 1 as an example, its structure and performance are studied: Combination Figure 2 As shown in the transmission electron microscope (TEM) image of the polydopamine nanospheres, the prepared nanospheres have a particle size of about 150 nm, regular morphology, and uniform size.

[0034] Combination Figure 3 As shown, the biomimetic self-healing polyurethane material reinforced with polydopamine nanospheres prepared in this embodiment has a tensile strength of 31.8 MPa and an elongation at break of 1220%, which is a significant improvement in performance compared with the control group without polydopamine nanospheres (tensile strength 7.0 MPa, elongation at break 1757%).

[0035] The test results of the mechanical properties and self-healing properties of Example 1 are shown in Table 1: Table 1. Test results of mechanical properties and self-healing properties of Example 1

[0036] As shown in Table 1, the biomimetic self-healing polyurethane material reinforced with polydopamine nanospheres prepared in this embodiment has a room temperature self-healing function. After being cut and repaired, its mechanical properties can be restored to more than 90% of the original mechanical properties after being placed at room temperature for 48 hours.

[0037] Example 2: This embodiment provides a biomimetic self-healing polyurethane material reinforced with polydopamine nanospheres, which is prepared according to the following method: Step 1: Dissolve 1g of dopamine hydrochloride in 200 mL of Tirs-HCl 8.5 buffer solution, stir at room temperature for 6 hours, and obtain polydopamine nanospheres by centrifugation, washing and drying.

[0038] Step 2: In a 100 mL three-necked flask equipped with a mechanical stirrer, thermometer, and reflux device, 20 g (10 mmol) of polytetrahydrofuran was dehydrated under vacuum at 100 °C for 2 h, and then cooled to 70 °C. 4.4 g (20 mmol) of isophorone diisocyanate and 0.06 g (0.1 mmol) of dibutyltin dilaurate catalyst were mixed in 40 mL of N,N-dimethylformamide and added to the dried polytetrahydrofuran. The mixture was reacted under a nitrogen atmosphere for 3 h to prepare the prepolymer.

[0039] Step 3: Mix 2.5g (10mmol) of 4,4'-dithiodiphenylamine in 10mL of N,N-dimethylformamide, add it to the prepolymer solution, heat to 70℃ and keep warm for 3h to react and obtain a polyurethane solution.

[0040] Step 4: Disperse 270 mg of polydopamine nanospheres in N,N-dimethylformamide and add them to a polyurethane solution (the mass fraction of polydopamine nanospheres is 1 wt%). After mixing evenly, place the solution in a vacuum oven and heat at 90°C for 24 hours for curing and molding to obtain the biomimetic self-healing polyurethane material reinforced with polydopamine nanospheres.

[0041] Example 3: This embodiment provides a biomimetic self-healing polyurethane material reinforced with polydopamine nanospheres, which is prepared according to the following method: Step 1: Dissolve 1g of dopamine hydrochloride in 200 mL of Tirs-HCl 8.5 buffer solution, stir at room temperature for 6 hours, and obtain polydopamine nanospheres by centrifugation, washing and drying.

[0042] Step 2: In a 100 mL three-necked flask equipped with a mechanical stirrer, thermometer, and reflux device, 20 g (10 mmol) of polytetrahydrofuran was dehydrated under vacuum at 100 °C for 2 h, and then cooled to 70 °C. 4.4 g (20 mmol) of isophorone diisocyanate and 0.06 g (0.1 mmol) of dibutyltin dilaurate catalyst were mixed in 40 mL of N,N-dimethylformamide and added to the dried polytetrahydrofuran. The mixture was reacted under a nitrogen atmosphere for 3 h to prepare the prepolymer.

[0043] Step 3: Mix 2.5g (10mmol) of 4,4'-dithiodiphenylamine in 10mL of N,N-dimethylformamide, add it to the prepolymer solution, heat to 70℃ and keep warm for 3h to react and obtain a polyurethane solution.

[0044] Step 4: Disperse 540 mg of polydopamine nanospheres in N,N-dimethylformamide and add them to a polyurethane solution (the mass fraction of polydopamine nanospheres is 2 wt%). After mixing evenly, place the solution in a vacuum oven and heat at 90°C for 24 hours for curing and molding to obtain the biomimetic self-healing polyurethane material reinforced with polydopamine nanospheres.

[0045] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a biomimetic composite material reinforced with polydopamine nanospheres, characterized in that the steps include... include: Step 1: After drying polytetrahydrofuran, isophorone diisocyanate and dibutyltin dilaurate are mixed in an organic solvent and then added to the dried polytetrahydrofuran. The prepolymer is prepared by reacting under a nitrogen protective atmosphere. Step 2: Dissolve 4,4'-dithiodiphenylamine in an organic solvent, add it to the prepolymer, and react at 70°C for 3 hours to obtain a polyurethane solution; Step 3: Dissolve polydopamine nanospheres in an organic solvent, add them to a polyurethane solution, mix thoroughly, and then cure and mold to obtain the final product.

2. The method for preparing the biomimetic composite material reinforced with polydopamine nanospheres according to claim 1, characterized in that, In step one, the molar ratio of polytetrahydrofuran, isophorone diisocyanate and dibutyltin dilaurate is 1:2:0.

01.

3. The method for preparing the biomimetic composite material reinforced with polydopamine nanospheres according to claim 1 or 2, characterized in that, In step two, the molar ratio of the prepolymer to 4,4'-dithiodiphenylamine is 1:

1.

4. The method for preparing the biomimetic composite material reinforced with polydopamine nanospheres according to claim 1 or 2, characterized in that, The organic solvent is tetrahydrofuran or N,N-dimethylformamide.

5. The method for preparing the biomimetic composite material reinforced with polydopamine nanospheres according to claim 1 or 2, characterized in that, The preparation of the polydopamine nanospheres includes: Dopamine hydrochloride was dissolved in Tirs-HCl buffer and stirred at room temperature for 6 hours. After centrifugation, washing and drying, polydopamine nanospheres were obtained. The concentration of the Tirs-HCl buffer solution is 0.01 M, and the pH value is 8.

5.

6. The method for preparing the biomimetic composite material reinforced with polydopamine nanospheres according to claim 1 or 2, characterized in that, The particle size range of the polydopamine nanospheres is 100–200 nm; The mass percentage of polydopamine nanospheres to polyurethane is 0.1–5 wt%.

7. The method for preparing the biomimetic composite material reinforced with polydopamine nanospheres according to claim 1 or 2, characterized in that, The polytetrahydrofuran has a number-average molecular weight of 2000.

8. The method for preparing the biomimetic composite material reinforced with polydopamine nanospheres according to claim 1 or 2, characterized in that, The drying of polytetrahydrofuran includes: vacuum dehydration at 100°C for 2 hours, followed by cooling to 70°C; In step one, the reaction is carried out in a nitrogen protective atmosphere for 3 hours.

9. A biomimetic composite material reinforced with polydopamine nanospheres, characterized in that, The biomimetic composite material reinforced with polydopamine nanospheres as described in any one of claims 1-8 was prepared.

10. The application of the biomimetic composite material reinforced with polydopamine nanospheres as described in claim 9 in the preparation of solid propellant binders.

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