Intrinsic photothermal polyimide and preparation method and application thereof

Abstract

The present invention belongs to the technical field of polymer chemistry, and specifically relates to a polyimide and a preparation method and application thereof. The present invention introduces a diamine monomer with a photothermal effect to give the polyimide with excellent mechanical properties certain photothermal properties. Through molecular regulation, the polyimide can have good photothermal properties in the ultraviolet to visible light region, and has the excellent chemical resistance stability, thermal stability, etc. of the polyimide itself. The intrinsic photothermal polyimide can achieve photothermal conversion without external energy consumption, and can be used for a long time in harsh environments.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer chemistry, and specifically relates to an intrinsic photothermal polyimide and a preparation method and application thereof. Background Art

[0002] In recent years, due to the rapid growth of the world's population and the acceleration of modernization, energy consumption has increased dramatically. In order to obtain cleaner energy, solar energy, an inexhaustible energy source, has attracted widespread attention from researchers. Thermal energy is essential for human production and life. There are many ways to obtain thermal energy, among which photothermal conversion is the most convenient, efficient and economical, thus achieving successful applications in biomedicine, catalysis, motors and actuators. Materials with efficient solar thermal effect can achieve significant temperature rise only by sunlight without external energy consumption, and have a wide range of applications in many fields such as seawater desalination and photothermal energy storage. Prior to this, researchers' research on photothermal materials mostly focused on carbon-based materials, metal nanomaterials and semiconductor materials, which are expensive.

[0003] In recent years, organic polymers have a small band gap due to their long conjugated structure, which allows them to have a wide absorption range from visible to near-infrared light, but their mechanical properties are poor. Polyimide is a polymer material with good mechanical properties and excellent thermal stability. Previously, most studies have obtained composites with high mechanical properties and photothermal effects by compounding materials with high molar extinction coefficients such as carbon black and carbon nanotubes with polyimide, but these materials will destroy the properties of the polyimide itself. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the present invention provides an intrinsic photothermal polyimide and a preparation method and application thereof. The polyimide provided by the present invention has intrinsic photothermal properties and good mechanical properties.

[0005] In order to achieve the above objectives, the present invention provides the following technical solutions.

[0006] The present invention provides an intrinsic photothermal polyimide having a structure shown in Formula I:

[0007]

[0008] In Formula I, R1 is

[0009] R2 is

[0010] The value range of n in formula I is 10 to 10000 。

[0011] The present invention also provides a method for preparing the intrinsic photothermal polyimide, comprising the following steps:

[0012] The dianhydride and diamine monomers are dissolved in a non-protonic strong polar solvent, and amidation reaction is carried out in a protective atmosphere to obtain a viscous PAA solution;

[0013] The viscous PAA solution and triethylamine are mixed, and the resulting solution is dried after being precipitated with an organic solvent to obtain a PAA solid;

[0014] Thermally imidizing the PAA solid to obtain the intrinsic photothermal polyimide;

[0015] The dianhydride monomer is any one of formulas II to VI;

[0016]

[0017] The diamine monomer is any one of Formulas 1 to 6:

[0018]

[0019] Preferably, the aprotic strong polar solvent is any one of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, N-ethyl-2-pyrrolidone and tetrahydrofuran.

[0020] Preferably, the temperature of the amidation reaction is 0°C to 5°C, and the reaction time is 12 to 24 hours.

[0021] Preferably, the molar ratio of the dianhydride to the diamine monomer is 1:1.

[0022] Preferably, the volume ratio of the viscous PAA solution to triethylamine is 25:1-1.5.

[0023] Preferably, the procedure of the thermal imidization is:

[0024] Heat to 80°C for 1 h;

[0025] Heat from 80°C to 150°C and maintain for 1h to 2h;

[0026] Heat from 150°C to 200°C and maintain for 1h to 2h;

[0027] Heat from 200°C to 250°C and maintain for 1h to 2h;

[0028] Heat from 250°C to 300°C and maintain for 1h to 2h.

[0029] The intrinsic photothermal polyimide provided by the present invention or the intrinsic photothermal polyimide prepared by the preparation method is used in the field of solar seawater desalination or crude oil collection.

[0030] The present invention provides an intrinsic photothermal polyimide having a structure shown in Formula I:

[0031]

[0032] In Formula I, R1 is

[0033] R2 is The value range of n in formula I is 10 to 10000. The present invention introduces a diamine monomer with a photothermal effect to give the polyimide with excellent mechanical properties certain photothermal properties. Through molecular regulation, the polyimide powder can have good photothermal properties in the ultraviolet to visible light region, and has the excellent chemical resistance and thermal stability of the polyimide itself. The intrinsic photothermal polyimide can achieve photothermal conversion without external energy consumption and can be used for a long time in harsh environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a physical picture of the intrinsic photothermal polyimide in Example 1;

[0035] Figure 2 This is the infrared image of the intrinsic photothermal polyimide in Example 1;

[0036] Figure 3 This is the solar light temperature rise diagram of the intrinsic photothermal polyimide in Example 1;

[0037] Figure 4 This is the UV-visible absorption diagram of the intrinsic photothermal polyimide in Example 1. DETAILED DESCRIPTION

[0038] The present invention provides an intrinsic photothermal polyimide having a structure shown in Formula I:

[0039]

[0040] In Formula I, R1 is

[0041]

[0042] R2 is

[0043] The value range of n in formula I is 10 to 10000.

[0044] The present invention also provides a method for preparing the intrinsic photothermal polyimide described above, comprising the following steps:

[0045] The dianhydride and diamine monomers are dissolved in a non-protonic strong polar solvent, and amidation reaction is carried out in a protective atmosphere to obtain a viscous PAA solution;

[0046] The viscous PAA solution and triethylamine are mixed, and the resulting solution is dried after being precipitated with an organic solvent to obtain a PAA solid;

[0047] The PAA solid is thermally imidized to obtain the polyimide.

[0048] The present invention dissolves dianhydride and diamine monomers in a non-protonic strong polar solvent, performs an amidation reaction in a protective atmosphere, and obtains a viscous PAA solution;

[0049] The dianhydride monomer is any one of formulas II to VI;

[0050]

[0051] The diamine monomer is any one of Formulas 1 to 6:

[0052]

[0053] In the present invention, the molar ratio of the dianhydride to the diamine monomer is preferably 1:1.

[0054] In the present invention, the amidation reaction temperature is preferably 0°C to 5°C, and the reaction time is preferably 12 to 24 hours, more preferably 15 to 20 hours.

[0055] After obtaining the viscous PAA solution, the present invention mixes the viscous PAA solution with triethylamine, and the obtained solution is dried after precipitation with an organic solvent to obtain a PAA solid.

[0056] In the present invention, the volume ratio of the viscous PAA solution to triethylamine is preferably 25:1-1.5, more preferably 25:1.4.

[0057] In the present invention, the organic solvent is preferably acetone.

[0058] In the present invention, after the sedimentation and before the drying, the system obtained by the sedimentation is preferably filtered, and the solid phase obtained by the filtration is washed.

[0059] In the present invention, the washing agent is preferably deionized water. In the present invention, the drying temperature is preferably 40° C. to 80° C., and the drying time is preferably 2 to 4 hours.

[0060] After obtaining the PAA solid, the present invention performs thermal imidization on the PAA solid to obtain the polyimide.

[0061] In the present invention, the thermal imidization procedure is preferably: heating to 80°C and maintaining for 1 hour; heating from 80°C to 150°C and maintaining for 1 hour to 2 hours; heating from 150°C to 200°C and maintaining for 1 hour to 2 hours; heating from 200°C to 250°C and maintaining for 1 hour to 2 hours; heating from 250°C to 300°C and maintaining for 1 hour to 2 hours; more preferably: heating to 80°C and maintaining for 1 hour; heating from 80°C to 150°C and maintaining for 1.5 hours; heating from 150°C to 200°C and maintaining for 1.5 hours; heating from 200°C to 250°C and maintaining for 1.5 hours; heating from 250°C to 300°C and maintaining for 1.5 hours.

[0062] The characteristic of the present invention is that a diamine monomer having a photothermal effect in the ultraviolet region or near-infrared region is introduced to obtain a polyimide having a certain photothermal effect through simple polycondensation. The successful preparation of such polyimide gives such material better solar photothermal effect, thermal stability and excellent mechanical properties.

[0063] The present invention also provides the use of the intrinsic photothermal polyimide described above in the field of solar seawater desalination or crude oil collection.

[0064] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0065] Example 1

[0066] Preparation of intrinsic photothermal polyimide PI-1:

[0067]

[0068] (1) The Shrek polymerizer tube was cleaned, 2.18 g (0.01 mol) of pyromellitic anhydride (PMDA) was added, and then 25 mL of N,N-dimethylformamide (DMF) was added and dissolved by ultrasonication. Then, 3.35 g (0.01 mol) of CRO-1 (Formula 2) was added. After three vacuum evacuations and nitrogen bubbling processes, water and oxygen were removed. Then, the mixture was reacted in a nitrogen atmosphere in an ice-water bath (0°C) for 24 h. After that, 1.4 mL (0.1 mol) of triethylamine (TEA) was added and stirred for 2 h to produce a dark green viscous liquid. Then, acetone was poured into the mixture for precipitation. The obtained product was filtered, washed, and dried to obtain soluble PAA-1.

[0069] The obtained PAA-1 powder was placed on a hot plate and thermally imidized in air, and the temperature was raised according to the following procedure: heated to 80°C and maintained for 1 hour, then continued to heat to 100°C and maintained for 1 hour, 150°C and maintained for 1 hour, 200°C and maintained for 1 hour, 250°C and maintained for 1 hour, and 300°C and maintained for 1 hour to obtain intrinsic photothermal polyimide PI-1.

[0070] Figure 1 This is a physical picture of the intrinsic photothermal polyimide of Example 1. Figure 1 It can be observed that the surface of polyimide is brownish yellow, which is very conducive to the full spectrum absorption of sunlight.

[0071] Figure 2 This is the infrared image of the intrinsic polyimide of Example 1, according to 1743cm -1 and 1706cm -1 Asymmetric stretching vibration and symmetric stretching vibration of C=O, 1378cm -1 The emergence of stretching vibration in the CNC absorption band indicates that the intrinsic photothermal polyimide has been successfully synthesized.

[0072] Figure 3 This is a photothermal effect diagram of the intrinsic polyimide carbon in Example 1. Under a simulated solar radiation condition, the temperature can be raised to 42.5°C.

[0073] Figure 4 This is the absorption diagram of the intrinsic polyimide in the ultraviolet to visible light region of Example 1. It can be seen that the polyimide has a wide absorption in this region, which also shows that it has an excellent photothermal effect.

[0074] Example 2

[0075] Preparation of intrinsic photothermal polyimide PI-2:

[0076]

[0077] (1) The Shrek polymerization tube was cleaned, and 2.18 g (0.01 mol) of PMDA was added, followed by 25 mL of N,N-dimethylformamide (DMF), and ultrasonically dissolved. Subsequently, 3.07 g (0.01 mol) of CRO-2 (Formula 1) was added, and the mixture was vacuum-pumped and nitrogen-bubbled for three times to remove water and oxygen. The mixture was reacted in a nitrogen atmosphere in an ice-water bath (0°C) for 24 h, and then 1.4 mL (0.1 mol) of triethylamine (TEA) was added and stirred for 2 h to produce a dark viscous liquid. The mixture was then poured into acetone for precipitation. The obtained product was filtered, washed, and dried to obtain soluble PAA-2.

[0078] (2) Preparation of photothermal polyimide

[0079] The obtained PAA-2 was placed on a hot plate and thermally imidized in air, and the temperature was raised according to the following program: heated to 80°C and maintained for 1 hour, then continued to heat to 100°C and maintained for 1 hour, 150°C and maintained for 1 hour, 200°C and maintained for 1 hour, 250°C and maintained for 1 hour, and 300°C and maintained for 1 hour to obtain intrinsic photothermal polyimide PI-2.

[0080] Example 3

[0081] Preparation of intrinsic photothermal polyimide PI-3:

[0082]

[0083] (1) The Shrek polymer tube was cleaned, 3.22 g (0.01 mol) of BTDA was added, and then 25 mL of DMF was added for ultrasonic dissolution. Subsequently, 3.35 g (0.01 mol) of CRO-1 (Formula 2) was added. After three vacuum and nitrogen blowing processes, water and oxygen were removed. The mixture was reacted in a nitrogen atmosphere in an ice-water bath (0°C) for 24 h. Then, 1.4 mL (0.1 mol) of triethylamine (TEA) was added and stirred for 2 h to produce a dark viscous liquid. The mixture was then poured into acetone for precipitation. The obtained product was filtered, washed, and dried to obtain soluble PAA-3.

[0084] (2) Preparation of photothermal polyimide

[0085] The obtained PAA-3 was placed on a hot plate and thermally imidized in air, and the temperature was raised according to the following program: heated to 80°C and maintained for 1 hour, then continued to heat to 100°C and maintained for 1 hour, 150°C and maintained for 1 hour, 200°C and maintained for 1 hour, 250°C and maintained for 1 hour, and 300°C and maintained for 1 hour to obtain intrinsic photothermal polyimide PI-3.

[0086] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. An intrinsic photothermal polyimide, characterized in that: It has the structure shown in formula I: In Formula I, R1 is R2 is The value range of n in formula I is 10 to 10000 。 2. The method for preparing the intrinsic photothermal polyimide according to claim 1, characterized in that: The following steps are involved: The dianhydride and diamine monomers are dissolved in a non-protonic strong polar solvent, and amidation reaction is carried out in a protective atmosphere to obtain a viscous PAA solution; The viscous PAA solution and triethylamine are mixed, and the resulting solution is dried after being precipitated with an organic solvent to obtain a PAA solid; Thermally imidizing the PAA solid to obtain the intrinsic photothermal polyimide; The dianhydride monomer is any one of formulas II to VI; The diamine monomer is any one of Formulas 1 to 6:

3. The preparation method according to claim 2, characterized in that: The aprotic strong polar solvent is any one of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, N-ethyl-2-pyrrolidone and tetrahydrofuran.

4. The preparation method according to claim 2, characterized in that: The temperature of the amidation reaction is 0°C to 5°C, and the reaction time is 12 to 24 hours.

5. The preparation method according to claim 2, characterized in that: The molar ratio of the dianhydride to the diamine monomer is 1:

1.

6. The preparation method according to claim 2, characterized in that: The volume ratio of the viscous PAA solution to triethylamine is 25:1-1.

5.

7. The preparation method according to claim 2, characterized in that: The procedure of the thermal imidization is: Heat to 80°C for 1 h; Heat from 80°C to 150°C and maintain for 1h to 2h; Heat from 150°C to 200°C and maintain for 1h to 2h; Heat from 200°C to 250°C and maintain for 1h to 2h; Heat from 250°C to 300°C and maintain for 1h to 2h.

8. Use of the intrinsic photothermal polyimide according to claim 1 or the intrinsic photothermal polyimide prepared by the preparation method according to any one of claims 2 to 7 in the field of solar seawater desalination or crude oil collection.

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