Preparation method of polyurea elastomer containing multiple hydrogen bonds and metal coordination bonds

Abstract

The invention discloses a preparation method of a polyurea elastomer containing multiple hydrogen bonds and metal coordination bonds, aiming at the problem of poor repeated processability of a single dynamic bond and a cross-linked polyurea elastomer, the multiple hydrogen bonds are introduced through dihydrazide chain extension, and network toughness integration is realized through coordination of pyridine and metal ions, so that the toughness of the polyurea elastomer is improved. A polyurea elastomer containing multiple hydrogen bonds and metal coordination bonds is developed. The specific method comprises the following steps: firstly, preparing an isocyanate-terminated prepolymer A, secondly, quantitatively adding the isocyanate-terminated prepolymer A, 2, 6-diaminopyridine, dihydrazide, metal chloride and a catalyst into a solvent according to a certain sequence, stirring and reacting to obtain the double dynamic network polyurea elastomer, and finally forming a product by adopting a polymer secondary processing mode. The raw materials are cheap and easy to obtain, and the preparation process is simple and efficient and suitable for batch production.

Description

Technical Field

[0001] The invention belongs to the field of thermoplastic (polyurea) elastomers, and in particular relates to a method for preparing a polyurea elastomer containing multiple hydrogen bonds and metal coordination bonds. Background Art

[0002] Polyurea elastomers are polymer elastomer materials containing urea (-NHCONH-) segments on the main chain, usually prepared by the reaction of diisocyanates and diamines, and are widely used in many fields such as energy-absorbing materials, coatings, electronic skin, and wearable electronic devices. Polyurea has excellent corrosion resistance, wear resistance, waterproofness, and impact resistance, and has high mechanical strength and good elasticity, which has attracted extensive attention from researchers.

[0003] The urea bonds of polyurea elastomers are rich in N, O, and H elements, which allow a large number of hydrogen bonds to form between molecular chains, thereby improving the mechanical properties and strain rate responsiveness of the elastomer. As a non-covalent interaction, hydrogen bonds can form strong interaction forces between or within molecules, thereby enhancing the mechanical properties and self-healing ability of the material. Compared with traditional hydrogen bonds, the introduction of multiple hydrogen bonds will be conducive to further improving the comprehensive mechanical properties of polyurea, and multiple hydrogen bonds have significant advantages in constructing polyurea elastomers. At the same time, in recent years, various types of dynamic chemical bonds have shown good energy dissipation characteristics. Metal coordination bonds, as a metal coordination effect, enhance the mechanical properties of elastomers through coordination interactions between metal ions and ligands. Metal ions form coordination bonds with polymers containing coordination groups such as carboxyl, phosphonic acid, and pyridine, which can significantly improve the tensile strength and elongation at break of the material. The introduction of metal coordination bonds makes the originally loose covalent bond network more compact, thereby improving the overall performance of the material.

[0004] There are some difficulties in simultaneously introducing multiple hydrogen bonds and metal coordination bonds into polyurea elastomers. First, the formation conditions of hydrogen bonds and metal coordination bonds need to be precisely controlled to ensure that they can effectively cooperate in the material; second, the introduction of hydrogen bonds and metal coordination bonds requires precise ratio and reaction condition control; third, traditional polyurea elastomers may cause problems such as unclear molecular structure due to their rapid reaction. Therefore, the present invention adopts the prepolymer method to control the polyurea sequence structure, adopts solvent dilution to control the reaction process, and simultaneously introduces multiple hydrogen bonds and metal coordination bonds to form a new polyurea elastomer with clear molecular structure and clear network structure. Summary of the invention

[0005] The purpose of the present invention is to develop a polyurea elastomer containing multiple hydrogen bonds and metal coordination bonds, introduce dense urea bonds in the hard segment to realize multiple hydrogen bonds and zinc-pyridine metal coordination bonds, and the prepared polyurea elastomer has excellent tensile strength, elongation at break, impact resistance and thermal repetitive processing performance. The preparation process is simple, the reaction conditions are mild, the molecular structure is highly designed, and batch preparation is easy to achieve.

[0006] In order to achieve the above purpose, the technical solution is as follows:

[0007] Step (1): after long-chain diamine and short-chain diisocyanate are diluted evenly with a small amount of solvent, the diamine monomer dilution liquid is gradually added dropwise into the diisocyanate dilution liquid to obtain a terminal isocyanate prepolymer A.

[0008] Step (2): weigh 100 parts of the terminal isocyanate prepolymer A, add 0-8 parts of 2,6-diaminopyridine (DAP), add 1-20 parts of dihydrazide diluent, add 0.1-10 parts of metal chloride diluent, add 0-5 parts of catalyst, and obtain a colored suspension, ensure that the molar ratio of isocyanate to active hydrogen (including boron hydroxyl group and amino group) is 1: (0.95-1.05), heat and continue to stir until a clear solution is obtained, evenly pour it into a polytetrafluoroethylene mold, put it into a vacuum oven for drying to remove the solvent and solidify it, and obtain a dual dynamic network polyurea elastomer.

[0009] Step (3): Take an appropriate amount of dual dynamic network polyurea elastomer and use a compression molding process to obtain a sample for testing.

[0010] The long-chain diamine described in step (1) is any one of polyetheramine D400, polyetheramine D1000 and polyetheramine D2000.

[0011] The diisocyanate described in step (1) is any one of isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), and 4,4'-dicyclohexylmethane diisocyanate (HMDI).

[0012] The dihydrazide described in step (2) is any one of adipic acid dihydrazide (ADH) and isophthalic acid dihydrazide (IPDH).

[0013] The metal chloride described in step (2) is any one of zinc chloride, ferric chloride, ferrous chloride and cupric chloride.

[0014] The catalyst in step (2) is any one of triethylamine (TEA), bicycloguanidine (TBD), and dibutyltin dilaurate (DBTDL). The curing temperature in step (2) is room temperature or 60 degrees Celsius, and the curing time is 8 to 24 hours.

[0015] The present invention aims to solve the problem of poor repeatability of single dynamic bond and cross-linked polyurea elastomer by introducing multiple hydrogen bonds through dihydrazide chain extension, realizing network toughness integration through the coordination effect of 2,6-diaminopyridine and metal ions, and developing a polyurea elastomer containing multiple hydrogen bonds and metal coordination bonds.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The molecular sequence structure is controllable, the preparation process is simple, and it is suitable for industrial mass production.

[0018] 2. By introducing metal coordination bonds, the tensile toughness of polyurea elastomer is greatly improved.

[0019] 3. By introducing multiple hydrogen bonds, the strength and toughness of polyurea elastomers can be synergistically improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 .Infrared spectrum of double dynamic network polyurea elastomer

[0021] Figure 2 .Uniaxial tensile stress-strain curves of dual dynamic network polyurea elastomer

[0022] Figure 3 .Stress relaxation curve of dual dynamic network polyurea elastomer DETAILED DESCRIPTION

[0023] In order to further explain the technical solution of the present invention, the following is a specific description in conjunction with the embodiments, but the protection scope of the present invention is not limited to these embodiments, and non-essential improvements and adjustments made to the present invention by those skilled in the art all fall within the protection scope of the present invention.

[0024] Example 1

[0025] 2.1 parts of HMDI and 7.3 parts of polyetheramine D2000 were weighed by weight, and reacted at room temperature and pressure for 3 hours under nitrogen protection. Then 0.16 parts of DAP were weighed and diluted and added to the reaction system, and the reaction was continued for 1 hour. 0.44 parts of IPDH were weighed and dispersed and added to the reaction system at 60 degrees Celsius. After maintaining the reaction at 60 degrees Celsius for 2 hours, 0.17 parts of zinc chloride were weighed and dissolved in tetrahydrofuran and added to the reaction system. The reaction was continued for 20 hours to obtain a uniform and stable colored polymer solution. After stirring evenly, it was poured into a polytetrafluoroethylene mold, placed in a vacuum oven to remove the solvent and solidify, and a dual dynamic network polyurea elastomer 1 was obtained; it can be further hot-pressed into a film using a flat vulcanizer and cut into standard specimens for testing.

[0026] Example 2

[0027] Weigh 2.1 parts of HMDI and 7.3 parts of polyetheramine D2000 by weight, react at room temperature and pressure for 3 hours under nitrogen protection, then weigh 0.16 parts of DAP and prepare diluent and add to the reaction system, continue to react for 1 hour, weigh 0.44 parts of IPDH and prepare dispersion and add to the reaction system at 60 degrees Celsius, maintain 60 degrees Celsius for 2 hours, weigh 0.33 parts of zinc chloride dissolved in tetrahydrofuran and add to the reaction system, continue to react for 20 hours, and obtain a uniform and stable colored polymer solution. After stirring evenly, pour it into a polytetrafluoroethylene mold, place it in a vacuum oven to remove the solvent and solidify it, and obtain a dual dynamic network polyurea elastomer 2; it can be further hot-pressed into a film using a flat vulcanizer and cut into standard specimens for testing.

[0028] Example 3

[0029] Weigh 2.1 parts of HMDI and 7.3 parts of polyetheramine D2000 by weight, react at room temperature and pressure for 3 hours under nitrogen protection, then weigh 0.16 parts of DAP and prepare diluent and add to the reaction system, continue to react for 1 hour, weigh 0.44 parts of IPDH and prepare dispersion and add to the reaction system at 60 degrees Celsius, maintain 60 degrees Celsius for 2 hours, weigh 0.49 parts of zinc chloride dissolved in tetrahydrofuran and add to the reaction system, continue to react for 20 hours, and obtain a uniform and stable colored polymer solution. After stirring evenly, pour it into a polytetrafluoroethylene mold, place it in a vacuum oven to remove the solvent and solidify it, and obtain a dual dynamic network polyurea elastomer 3; it can be further hot-pressed into a film using a flat vulcanizer and cut into standard specimens for testing.

[0030] Example 4

[0031] Weigh 2.1 parts of HMDI and 7.3 parts of polyetheramine D2000 by weight, react at room temperature and pressure for 3 hours under nitrogen protection, then weigh 0.16 parts of DAP and prepare diluent and add to the reaction system, continue to react for 1 hour, weigh 0.44 parts of IPDH and prepare dispersion and add to the reaction system at 60 degrees Celsius, maintain 60 degrees Celsius for 2 hours, weigh 0.73 parts of zinc chloride dissolved in tetrahydrofuran and add to the reaction system, continue to react for 20 hours, and obtain a uniform and stable colored polymer solution. After stirring evenly, pour it into a polytetrafluoroethylene mold, place it in a vacuum oven to remove the solvent and solidify it, and obtain a dual dynamic network polyurea elastomer 4; it can be further hot-pressed into a film using a flat vulcanizer and cut into standard specimens for testing.

[0032] Example 5

[0033] Weigh 2.1 parts of HMDI and 7.3 parts of polyetheramine D2000 by weight, react at room temperature and pressure for 3 hours under nitrogen protection, then weigh 0.16 parts of DAP and prepare diluent and add to the reaction system, continue to react for 1 hour, weigh 0.44 parts of IPDH and prepare dispersion and add to the reaction system at 60 degrees Celsius, maintain 60 degrees Celsius for 2 hours, weigh 0.94 parts of zinc chloride dissolved in tetrahydrofuran and add to the reaction system, continue to react for 20 hours, and obtain a uniform and stable colored polymer solution. After stirring evenly, pour it into a polytetrafluoroethylene mold, place it in a vacuum oven to remove the solvent and solidify it, and obtain a dual dynamic network polyurea elastomer 5; it can be further hot-pressed into a film using a flat vulcanizer and cut into standard specimens for testing.

[0034] Comparative Example 1

[0035] 2.1 parts of HMDI and 7.3 parts of polyetheramine D2000 were weighed by weight, and reacted at room temperature and pressure for 3 hours under nitrogen protection, then 0.16 parts of DAP were weighed and prepared as a diluent and added to the reaction system, and the reaction was continued for 1 hour, 0.44 parts of IPDH were weighed as a dispersion and added to the reaction system at 60 degrees Celsius, and the reaction was continued at 60 degrees Celsius for 20 hours to obtain a uniform and stable transparent polymer solution. After stirring evenly, it was poured into a polytetrafluoroethylene mold, placed in a vacuum oven to remove the solvent and solidify, and a polyurea elastomer 1 was obtained; it can be further hot-pressed into a film using a flat vulcanizer, and cut into standard specimens for testing.

[0036] The above is only a typical optimized embodiment of the present invention, and is not any formal or substantial limitation of the present invention. Under the premise of not changing the method of the present invention, several improvements and supplements can be made, and these improvements and supplements should also be regarded as the protection scope of the present invention. For those skilled in the art, without departing from the scope of the present invention, the equivalent changes made by using the technical content disclosed above should be regarded as equivalent embodiments of the present invention and still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a polyurea elastomer containing multiple hydrogen bonds and metal coordination bonds, characterized in that The steps include: Step (1): after long-chain diamine and short-chain diisocyanate are diluted evenly with a small amount of solvent, the diamine monomer dilution liquid is gradually added dropwise into the diisocyanate dilution liquid to obtain a terminal isocyanate prepolymer A. Step (2): weigh 100 parts of the terminal isocyanate prepolymer A, add 0-8 parts of 2,6-diaminopyridine (DAP), add 1-20 parts of dihydrazide diluent, add 0.1-10 parts of metal chloride diluent, add 0-5 parts of catalyst, and obtain a colored suspension, ensure that the molar ratio of isocyanate to active hydrogen (including boron hydroxyl group and amino group) is 1: (0.95-1.05), heat and continue to stir until a clear solution is obtained, evenly pour it into a polytetrafluoroethylene mold, put it into a vacuum oven for drying to remove the solvent and solidify it, and obtain a dual dynamic network polyurea elastomer. Step (3): Take an appropriate amount of dual dynamic network polyurea elastomer and use a compression molding process to obtain a sample for testing.

2. The method for preparing a polyurea elastomer containing multiple hydrogen bonds and metal coordination bonds according to claim 1, characterized in that The long-chain diamine is any one of polyetheramine D400, polyetheramine D1000 and polyetheramine D2000.

3. The method for preparing a polyurea elastomer containing multiple hydrogen bonds and metal coordination bonds according to claim 1, characterized in that The diisocyanate is any one of isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI) and 4,4'-dicyclohexylmethane diisocyanate (HMDI).

4. The method for preparing a polyurea elastomer containing multiple hydrogen bonds and metal coordination bonds according to claim 1, characterized in that The dihydrazide is any one of adipic acid dihydrazide (ADH) and isophthalic acid dihydrazide (IPDH).

5. The method for preparing a polyurea elastomer containing multiple hydrogen bonds and metal coordination bonds according to claim 1, characterized in that The metal chloride is any one of zinc chloride, ferric chloride, ferrous chloride and cupric chloride.

6. The method for preparing a polyurea elastomer containing multiple hydrogen bonds and metal coordination bonds according to claim 1, characterized in that The catalyst is any one of triethylamine (TEA), bicyclic guanidine (TBD) and dibutyltin dilaurate (DBTDL).

7. The method for preparing a polyurea elastomer containing multiple hydrogen bonds and metal coordination bonds according to claim 1, characterized in that The polyurea molecular chain sequence and cross-linked network structure are metered and controlled by the addition sequence and amount of each added component.

8. The method for preparing a polyurea elastomer containing multiple hydrogen bonds and metal coordination bonds according to claim 1, characterized in that The curing temperature is 40 to 60 degrees Celsius, and the curing time is 8 to 24 hours.

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