A poly (urethane-imide) and its preparation method and application

Abstract

The present invention provides a poly (urethane-imide) and a preparation method and application thereof, belonging to the field of polymer materials. The present invention innovatively utilizes polyimide molecular segments as rigid units to improve the strength of the material, and the supramolecular interaction (hydrogen bond) inside the material can improve the toughness of the material, and the rigid polyimide molecules are introduced into the polycarbonate-based polyurethane prepolymer with flexible segments by grafting and modifying the polyurethane, and the advantages of the high strength of the polyimide and the high extensibility of the polyurethane are integrated, and a material having both high strength and high toughness is prepared, and compared with traditional polyurethane materials, the poly (urethane-imide) provided by the present invention has very excellent mechanical properties.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a poly(urethane-imide) and a preparation method and application thereof. Background Art

[0002] With the advancement of science and technology, people have put forward more stringent requirements on the performance of materials, among which the mechanical properties of materials have attracted much attention as a research hotspot. The strength and toughness of materials are often not achieved at the same time. Stronger materials are usually more brittle, while materials with good toughness are usually lower in strength.

[0003] Polyurethane is widely used in various fields due to its good heat insulation, shock resistance, wear resistance, and aging resistance. However, compared with engineering plastics such as polyimide and polyetheretherketone, the strength of polyurethane is still relatively poor. Constructing a cross-linked network through molecular design or adding fillers is a common method to improve polyurethane materials. However, the introduction of cross-linked networks or fillers makes it difficult for the molecular network to move, resulting in poor chain mobility and low toughness. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a poly(urethane-imide) and a preparation method and application thereof. The poly(urethane-imide) prepared by the present invention has both high strength and high toughness.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing poly(urethane-imide), comprising the following steps:

[0007] The polycarbonate diol, hexamethylene diisocyanate, dibutyltin dilaurate and an organic solvent are mixed to undergo a nucleophilic addition reaction to obtain a polycarbonate-based polyurethane prepolymer;

[0008] The polycarbonate-based polyurethane prepolymer, the amino-terminated bisimide, 5,5′-diamino-2,2′-bipyridine and an organic solvent are mixed to carry out a polymerization reaction to obtain the poly(urethane-imide).

[0009] Preferably, the molar ratio of hexamethylene diisocyanate to polycarbonate diol is (2-3):1.

[0010] Preferably, the temperature of the nucleophilic addition reaction is 60-80° C. and the time is 2-4 hours.

[0011] Preferably, the molar ratio of the amino-terminated bisimide to hexamethylene diisocyanate is (2-3): (0.16-0.24).

[0012] Preferably, the molar ratio of the 5,5′-diamino-2,2′-bipyridine to hexamethylene diisocyanate is (2-3): (0.84-1.76).

[0013] Preferably, the polymerization reaction temperature is 60-80° C. and the time is 2-4 hours.

[0014] Preferably, the amine-terminated bisimide is prepared by a method comprising the following steps:

[0015] 4,4'-diaminodiphenyl ether, 4,4'-(4,4'-isopropyldiphenyloxy) diphthalic anhydride and an organic solvent are mixed to carry out low-temperature polycondensation and dehydration reaction to obtain the amino-terminated bisimide.

[0016] Preferably, the temperature of the low-temperature polycondensation is 0-10°C, the time is 12-24 hours, and the temperature of the dehydration reaction is 200-240°C, the time is 5-7 hours.

[0017] The present invention also provides poly(urethane-imide) prepared by the preparation method described in the above technical scheme.

[0018] The present invention also provides the application of the poly(urethane-imide) described in the above technical solution in mechanical materials and toughness materials.

[0019] The invention provides a preparation method of poly(urethane-imide) (PUI, "I" is the abbreviation of polyimide (polyimide), and "U" is the abbreviation of polyurethane (polyurethane)). The method comprises the following steps: mixing polycarbonate diol (PCDL), hexamethylene diisocyanate (HDI), dibutyltin dilaurate and an organic solvent for nucleophilic addition reaction to obtain a polycarbonate-based polyurethane prepolymer; and mixing the polycarbonate-based polyurethane prepolymer, amino-terminated bisimide (ATBI), 5,5'-diamino-2,2'-bipyridine and an organic solvent for polymerization reaction to obtain the poly(urethane-imide).

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention innovatively utilizes polyimide molecular segments as rigid units to improve the strength of the material, while the supramolecular interaction (hydrogen bond) inside the material can improve the toughness of the material. By grafting and modifying polyurethane, rigid polyimide molecules are introduced into a polycarbonate-based polyurethane prepolymer with flexible segments, and the advantages of high strength of polyimide and high elongation of polyurethane are integrated to prepare a material with both high strength and high toughness. Compared with traditional polyurethane materials, the poly(urethane-imide) provided by the present invention has very excellent mechanical properties.

[0022] The present invention also provides poly(urethane-imide) prepared by the preparation method described in the above technical solution, and the mechanical properties of the polyurethane are greatly changed before and after the introduction of polyimide, indicating that the polyimide has an effect on improving the mechanical properties of polyurethane. DETAILED DESCRIPTION

[0023] The present invention provides a method for preparing poly(urethane-imide), comprising the following steps:

[0024] The polycarbonate diol, hexamethylene diisocyanate, dibutyltin dilaurate and an organic solvent are mixed to undergo a nucleophilic addition reaction to obtain a polycarbonate-based polyurethane prepolymer;

[0025] The polycarbonate-based polyurethane prepolymer, the amino-terminated bisimide, 5,5′-diamino-2,2′-bipyridine and an organic solvent are mixed to carry out a polymerization reaction to obtain the poly(urethane-imide).

[0026] In the present invention, the raw materials used are all commercially available products in the art.

[0027] The invention mixes polycarbonate diol, hexamethylene diisocyanate, dibutyltin dilaurate and an organic solvent to carry out a nucleophilic addition reaction to obtain a polycarbonate-based polyurethane prepolymer.

[0028] In the present invention, the molar ratio of hexamethylene diisocyanate to polycarbonate diol is preferably (2-3):1.

[0029] In the present invention, the M of the polycarbonate diol n Preferably 2000.

[0030] In the present invention, the polycarbonate diol is preferably dried before use. The drying is preferably carried out in a vacuum oven. The temperature of the drying is preferably 110 to 130° C. and the time is preferably 3 to 7 hours.

[0031] In the present invention, the dibutyltin dilaurate is used as a catalyst. The present invention has no special limitation on the amount of the dibutyltin dilaurate, and any amount known to those skilled in the art can be used.

[0032] In the present invention, the organic solvent preferably includes N,N-dimethylformamide. The present invention has no particular limitation on the amount of the organic solvent used, as long as the raw materials can be completely dissolved.

[0033] In the present invention, the temperature of the nucleophilic addition reaction is preferably 60 to 80° C., and the time is preferably 2 to 4 hours.

[0034] In the present invention, the nucleophilic addition reaction is preferably carried out in a nitrogen atmosphere.

[0035] In the present invention, the polycarbonate diol is preferably dissolved in an organic solvent, and then the dibutyltin dilaurate is added to obtain a mixed solution, and the hexamethylene diisocyanate is dissolved in an organic solvent and then mixed with the mixed solution.

[0036] After obtaining the polycarbonate-based polyurethane prepolymer, the present invention mixes the polycarbonate-based polyurethane prepolymer, amine-terminated bisimide, 5,5′-diamino-2,2′-bipyridine and an organic solvent for polymerization reaction to obtain the poly(urethane-imide).

[0037] In the present invention, the amine-terminated bisimide is preferably prepared by a method comprising the following steps:

[0038] 4,4'-diaminodiphenyl ether, 4,4'-(4,4'-isopropyldiphenyloxy) diphthalic anhydride and an organic solvent are mixed to carry out low-temperature polycondensation and dehydration reaction to obtain the amino-terminated bisimide.

[0039] In the present invention, the temperature of the low-temperature polycondensation is preferably 0-10°C, the time is preferably 12-24h, the temperature of the dehydration reaction is preferably 200-240°C, and the time is preferably 5-7h. In a specific embodiment of the present invention, the amino-terminated bisimide is prepared by a method comprising the following steps:

[0040] Weigh 2.0 g of 4,4′-diaminodiphenyl ether (ODA) and dissolve it in 10-20 mL of organic solvent and add it to a three-necked flask. Weigh 4,4′-(4,4′-isopropyldiphenyloxy) diphthalic anhydride (BPADA) and dissolve it in 10-20 mL of organic solvent and add it to the above three-necked flask after dissolving. The three-necked flask is placed in an ice-water bath, stirred for reaction for 12-24 hours, and then 4-8 mL of toluene is added dropwise to the three-necked flask. A Dean-Stark device is connected, and a condenser is connected after the toluene is filled. The reaction is continued at 220° C. for 5-6 hours to remove water. After the reaction is completed, the solution in the three-necked flask is poured into 500-800 mL of ethanol and stirred continuously. The product is precipitated, filtered, and dried to obtain the amino-terminated bisimide.

[0041] In the present invention, the molar ratio of the amino-terminated bisimide to hexamethylene diisocyanate is preferably (2-3): (0.16-0.24).

[0042] In the present invention, the molar ratio of the 5,5′-diamino-2,2′-bipyridine to hexamethylene diisocyanate is preferably (2-3): (0.84-1.76). In the present invention, during the nucleophilic addition reaction, the hexamethylene diisocyanate is excessive, and during the polymerization reaction, the 5,5′-diamino-2,2′-bipyridine reacts with the remaining hexamethylene diisocyanate, and the amino group of the 5,5′-diamino-2,2′-bipyridine reacts with the hexamethylene diisocyanate to obtain a urea group, and hydrogen bonds can be generated between the urea groups, the urea groups and the carbamates, and the carbamates and the carbamates, thereby giving the material high toughness.

[0043] In the present invention, the polymerization reaction temperature is preferably 60 to 80° C., and the polymerization reaction time is preferably 2 to 4 hours.

[0044] In the present invention, the polymerization reaction is preferably carried out in a nitrogen atmosphere.

[0045] In the present invention, the organic solvent preferably includes N,N-dimethylformamide and / or N-methylpyrrolidone.

[0046] The present invention preferably dissolves the amino-terminated bisimide in N-methylpyrrolidone to obtain an amino-terminated bisimide solution, dissolves the 5,5′-diamino-2,2′-bipyridine in N,N-dimethylformamide to obtain a 5,5′-diamino-2,2′-bipyridine solution, mixes the amino-terminated bisimide solution with a polycarbonate-based polyurethane prepolymer, and then mixes with the 5,5′-diamino-2,2′-bipyridine solution.

[0047] In the present invention, after the polymerization reaction is completed, the present invention preferably further comprises removing the solvent to obtain the poly(urethane-imide). The present invention has no particular limitation on the specific method of removing the solvent, and any method familiar to those skilled in the art can be used.

[0048] The present invention also provides poly(urethane-imide) prepared by the preparation method described in the above technical scheme.

[0049] The present invention also provides the application of the poly(urethane-imide) described in the above technical solution in mechanical materials and toughness materials.

[0050] The present invention has no particular limitation on the specific manner of the application, and any manner familiar to those skilled in the art may be used.

[0051] In order to further illustrate the present invention, the poly(urethane-imide) provided by the present invention and its preparation method and application are described in detail below in conjunction with examples, but they should not be construed as limiting the scope of protection of the present invention.

[0052] In the embodiment, the amine-terminated bisimide is prepared by a method comprising the following steps:

[0053] Weigh 2.0 g of 4,4′-diaminodiphenyl ether (ODA) and dissolve it in 10-20 mL of organic solvent and add it to a three-necked flask. Weigh 4,4′-(4,4′-isopropyldiphenyloxy) diphthalic anhydride (BPADA) and dissolve it in 10-20 mL of organic solvent and add it to the above three-necked flask after dissolving. The three-necked flask is placed in an ice-water bath, stirred for reaction for 12-24 hours, and then 4-8 mL of toluene is added dropwise to the three-necked flask. A Dean-Stark device is connected, and a condenser is connected after the toluene is filled. The reaction is continued at 220° C. for 5-6 hours to remove water. After the reaction is completed, the solution in the three-necked flask is poured into 500-800 mL of ethanol and stirred continuously. The product is precipitated, filtered, and dried to obtain the amino-terminated bisimide.

[0054] The reactions in Examples 1 to 3 were all carried out in nitrogen.

[0055] Example 1

[0056] (1) Weigh polycarbonate diol (M n =2000) 5.00 g was placed in a three-necked flask and dried in a 120°C oven under vacuum for 5 h. Then, 20 mL of N,N-dimethylformamide and 5 drops of dibutyltin dilaurate were added and stirred evenly.

[0057] (2) 0.80 mL of hexamethylene diisocyanate was dissolved in 10 mL of N,N-dimethylformamide and added to a three-necked flask for nucleophilic addition reaction at 60 °C for 2 h.

[0058] (3) Weigh 0.45 g of ATBI and dissolve it in 40 mL of N-methylpyrrolidone. Add it and react for 1 h.

[0059] (4) Weigh 0.37 g of 5,5′-diamino-2,2′-bipyridine and dissolve it in 5 mL of N,N-dimethylformamide. Add it and react for 1 h. Finally, remove the solvent to obtain PUI.

[0060] Example 2

[0061] (1) Weigh polycarbonate diol (M n =2000) 5.00 g was placed in a three-necked flask and dried in a 120°C oven under vacuum for 5 h. Then, 20 mL of N,N-dimethylformamide and 5 drops of dibutyltin dilaurate were added and stirred evenly.

[0062] (2) 0.80 mL of hexamethylene diisocyanate was dissolved in 10 mL of N,N-dimethylformamide and added to a three-necked flask for nucleophilic addition reaction at 60 °C for 2 h.

[0063] (3) Weigh 0.36 g of ATBI and dissolve it in 30 mL of N-methylpyrrolidone. Add it and react for 1 h.

[0064] (4) Weigh 0.39 g of 5,5′-diamino-2,2′-bipyridine and dissolve it in 5 mL of N,N-dimethylformamide. Add it and react for 1 h. Finally, remove the solvent to obtain PUI.

[0065] Example 3

[0066] (1) Weigh polycarbonate diol (M n =2000) 5.00 g was placed in a three-necked flask and dried in a 120°C oven under vacuum for 5 h. Then, 20 mL of N,N-dimethylformamide and 5 drops of dibutyltin dilaurate were added and stirred evenly.

[0067] (2) 0.80 mL of hexamethylene diisocyanate was dissolved in 10 mL of N,N-dimethylformamide and added to a three-necked flask for nucleophilic addition reaction at 60 °C for 2 h.

[0068] (3) Weigh 0.54 g of ATBI and dissolve it in 30 mL of N-methylpyrrolidone. Add it and react for 1 h.

[0069] (4) Weigh 0.35 g of 5,5′-diamino-2,2′-bipyridine and dissolve it in 5 mL of N,N-dimethylformamide. Add it and react for 1 h. Finally, remove the solvent to obtain PUI.

[0070] Comparative Example 1

[0071] (1) Weigh polycarbonate diol (M n =2000) 5.0 g was placed in a three-necked flask and dried in a 120°C oven under vacuum for 5 h. Then, 20 mL of N,N-dimethylformamide and 5 drops of dibutyltin dilaurate were added and stirred evenly.

[0072] (2) Take 0.4 mL of hexamethylene diisocyanate, dissolve it in 15 mL of N,N-dimethylformamide, add it into a three-necked flask and react for 2 h.

[0073] Comparative Example 2

[0074] (1) Weigh polycarbonate diol (M n =2000) 5.0 g was placed in a three-necked flask and dried in a 120°C oven under vacuum for 5 h. Then, 20-40 mL of N,N-dimethylformamide and 5 drops of dibutyltin dilaurate were added and stirred evenly.

[0075] (2) Take 0.48 mL of hexamethylene diisocyanate, dissolve it in 20 mL of N,N-dimethylformamide, add it into a three-necked flask and react for 2 h.

[0076] (3) Weigh 0.45 g of ATBI and dissolve it in 10 mL of N-methylpyrrolidone. Add the mixture into a three-necked flask and react for 1 h.

[0077] Comparative Example 3

[0078] (1) Weigh polycarbonate diol (M n =2000) 5.0 g was placed in a three-necked flask and dried in a 120°C oven under vacuum for 5 h. Then, 20-40 mL of N,N-dimethylformamide and 5 drops of dibutyltin dilaurate were added and stirred evenly.

[0079] (2) Take 0.48 mL of hexamethylene diisocyanate, dissolve it in 25 mL of N,N-dimethylformamide, add it into a three-necked flask and react for 2 h.

[0080] (3) Weigh 0.37 g of 5,5′-diamino-2,2′-bipyridine and dissolve it in 7 mL of N,N-dimethylformamide. Add the mixture into a three-necked flask and react for 1 h.

[0081] The properties of the materials obtained in the examples and comparative examples were tested, and the results are shown in Table 1. It can be seen that the toughness of Example 2 is higher than that of Example 1. This is because the content of 5,5'-diamino-2,2'-bipyridine in Example 2 is higher than that in Example 1, and the urea group formed by 5,5'-diamino-2,2'-bipyridine can form high-density hydrogen bonds, so the hydrogen bond content of Example 2 is higher than that of Example 1, so Example 2 shows high toughness. When the ATBI content is the highest (Example 3), the material shows worse mechanical properties than Examples 1 and 2. This is because the presence of more ATBI causes stress concentration in some molecular segments, which has an adverse effect on the mechanical properties of the material; Comparative Examples 1 and 3 do not contain ATBI molecular segments, so they show lower strength. Although Comparative Example 2 contains ATBI molecular segments, it lacks 5,5'-diamino-2,2'-bipyridine (with a rigid structure), so it also shows lower strength relative to the examples.

[0082] In summary, the present invention introduces rigid polyimide molecules into polyurethane with flexible segments by grafting modification of polyurethane, combines the advantages of high strength of polyimide and high elongation of polyurethane, and prepares a material with both high strength and high toughness.

[0083] Table 1 Performance test results of materials obtained in Examples and Comparative Examples

[0084] Stress(MPa) strain(%) <![CDATA[Toughness (MJ / m 3 )]]> Example 1 76.86±2.85 1033.94±87.46 224.40±29.80 Example 2 69.29±1.37 1385.80±161.27 351.28±34.92 Example 3 62.83±4.35 957.69±36.72 207.33±1.56 Comparative Example 1 27.55±4.35 893.94±110.54 100.11±24.40 Comparative Example 2 60.75±6.66 1277.91±30.41 261.85±14.87 Comparative Example 3 57.87±2.65 1396.11±100.31 305.66±29.23

[0085] Note: The performance test parameters in the table are "mean ± standard deviation", which is the result of multiple measurements and statistical calculations.

[0086] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a poly(urethane-imide), characterized in that: The following steps are involved: The polycarbonate diol, hexamethylene diisocyanate, dibutyltin dilaurate and an organic solvent are mixed to undergo a nucleophilic addition reaction to obtain a polycarbonate-based polyurethane prepolymer; The polycarbonate-based polyurethane prepolymer, the amino-terminated bisimide, the 5,5′-diamino-2,2′-bipyridine and the organic solvent are mixed to carry out polymerization reaction to obtain the poly(urethane-imide); The amine-terminated bisimide is prepared by a method comprising the following steps: 4,4'-diaminodiphenyl ether, 4,4'-(4,4'-isopropyldiphenyloxy) diphthalic anhydride and an organic solvent are mixed to carry out low-temperature polycondensation and dehydration reaction to obtain the amino-terminated bisimide.

2. The preparation method according to claim 1, characterized in that: The molar ratio of the hexamethylene diisocyanate to the polycarbonate diol is (2-3):

1.

3. The preparation method according to claim 1, characterized in that: The temperature of the nucleophilic addition reaction is 60-80° C. and the time is 2-4 hours.

4. The preparation method according to claim 1, characterized in that: The polymerization reaction temperature is 60-80° C. and the reaction time is 2-4 hours.

5. The preparation method according to claim 1, characterized in that: The temperature of the low-temperature polycondensation is 0-10°C, and the time is 12-24 hours. The temperature of the dehydration reaction is 200-240°C, and the time is 5-7 hours.

6. The poly(urethane-imide) obtained by the preparation method according to any one of claims 1 to 5.

7. Use of the poly(urethane-imide) according to claim 6 in mechanical materials and toughness materials.