Polyarylether polymer containing Schiff base structure in main chain and preparation method of polyarylether polymer

Abstract

The invention belongs to the technical field of polymer synthesis. Specifically, the invention relates to a polyarylether polymer containing a Schiff base structure in a main chain and a preparation method of the polyarylether polymer. The invention also relates to a self-repairing coating containing the polyarylether polymer. The main chain structure of the molecular chain of the polyarylether polymer simultaneously contains the Schiff base and the aryl ether ketone (sulfone) structure, so that the polyarylether polymer material is endowed with excellent self-repairing capability and recoverability; the thermal performance of traditional polyaryletherketone (sulfone) is maintained, and meanwhile, the mechanical property and the processability are improved. The polyarylether polymer provided by the invention can be used in the fields of flexible electronics and the like. The method for preparing the polyarylether polymer is high in universality, suitable for preparing polyarylether resin from various bisphenol monomers and dihalogen monomers, good in repeatability and low in cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer synthesis. Specifically, the present invention relates to a polyarylether polymer containing a Schiff base structure in the main chain and a preparation method thereof. The present invention also relates to a self-healing coating comprising the polyarylether polymer. Background Art

[0002] Polyaryletherketone (PAEK) resins can be widely used in the fields of aerospace, electronics, medical devices, etc. due to their excellent high-temperature resistance (T g > 140 °C), mechanical strength (tensile strength > 80 MPa) and chemical stability. However, traditional PAEK resins have the following defects: First, petroleum-based monomer dependence: The main raw material bisphenol A (BPA) is a petroleum derivative, and its global annual consumption exceeds about 8 million tons, exacerbating the depletion of fossil resources; Second, environmental and health risks: BPA has been proven to have endocrine-disrupting toxicity, and its use in food contact materials has been restricted in some countries or regions; Third, non-recyclability: Traditional PAEK resins are thermoplastic materials, but they have a static molecular chain structure and are difficult to recycle through chemical structure degradation, resulting in the accumulation of waste; Fourth, single functionality: Traditional PAEK resins lack self-healing ability, and the propagation of microcracks easily leads to material failure.

[0003] In recent years, bio-based polymer materials (such as polylactic acid, polyhydroxyalkanoates) have received attention due to their renewability. However, their heat resistance (Tg < 100 °C) and mechanical properties (tensile strength < 50 MPa) are much lower than those of PAEK resins and cannot meet the usage requirements in the fields of packaging, coatings, etc.

[0004] Existing bio-based PAEK research mostly uses a single bio-based monomer (such as isosorbide), which can partially replace BPA. However, the bio-based PAEK resins prepared in the prior art have the following problems: First, performance loss: The introduction of bio-based monomers results in a decrease in the T g of PAEK resins by about 10 to about 20 °C; Second, lack of dynamics: The bio-based PAEK resins cannot achieve self-healing or controllable degradation; Third, process complexity: Multiple-step functional group modification increases the synthesis cost of bio-based PAEK resins.

[0005] In the PAEK resin, by introducing dynamic covalent bonds (such as Diels-Alder (DA) bonds or disulfide bonds, etc.) into the polyarylether main chain structure, it can endow the resin with self-healing and recyclability under external stimuli (heat, light, pH) conditions through the reversible cleavage and recombination of dynamic bonds. However, the existing dynamic bond systems (such as DA bonds) have the following problems: First, insufficient thermal stability: DA bonds may undergo reversible cleavage at temperatures from about 120 to about 150 °C, which cannot meet the processing temperature requirements of PAEK (about >300 °C); Second, sacrifice of mechanical properties: The introduction of dynamic bonds usually reduces the rigidity of the material.

[0006] Therefore, there is a need in the prior art for a new type of polyarylether polymer material that can replace conventional PAEK resins, has good mechanical properties, excellent self-healing properties, and can be reused. Summary of the Invention

[0007] Object of the Invention

[0008] In view of the problems existing in the prior art described in the above Background Art section, the object of the present invention is to provide a polyarylether polymer containing a Schiff base structure in the main chain and a preparation method thereof. The object of the present invention is also to provide a self-healing coating containing the polyarylether polymer and its uses.

[0009] Technical Solution

[0010] To achieve the above object, the present invention adopts the following technical solutions:

[0011] Solution 1: A polyarylether polymer containing a Schiff base structure in the main chain, wherein the polyarylether polymer has a main chain structure part represented by the following formula (I):

[0012]

[0013] In the formula (I),

[0014] n is a number such that the molecular weight of the polyarylether polymer is in the range of about 1.0×10 4 to about 3.0×10 4 Daltons;

[0015] M2 represents any one of the structural parts represented by the following formulas (M2-1), (M2-2), and (M2-3):

[0016]

[0017] Preferably,

[0018] M2 represents any one of the structural parts represented by the following formulas (M2-1-1), (M2-2-1), and (M2-3-1):

[0019]

[0020] wherein the symbol "*" in the formulas (M2-1), (M2-2), (M2-3), (M2-1-1), (M2-2-1), and (M2-3-1) respectively represents the positions where the O atom in formula (I) and the O atom of another adjacent formula (I) structural part are connected to each other;

[0021] M1 represents the structural part represented by the following formula (M1-1):

[0022] *-Ar1-CH=N-Ar2-N=CH-Ar1-*(M1-1)

[0023] wherein, in the formula (M1-1),

[0024] the symbol "*" respectively represents the positions where the O atoms in formula (I) are connected to each other;

[0025] Ar1 represents the group represented by the following formula (II):

[0026]

[0027] wherein, in the formula (II), the "*" on the bond in the meta position of the methoxy group represents the position connected to the C atom in the Schiff base structure in formula (M1-1), and the "*" on the bond in the ortho position of the methoxy group represents the position where the O atoms in formula (I) are connected to each other;

[0028] Ar2 represents any one of the structural parts represented by the following formulas (Ar2-1), (Ar2-2), (Ar2-3), and (Ar2-4)

[0029] :

[0030]

[0031] wherein,

[0032] the symbol "*" in the formulas (Ar2-1), (Ar2-2), (Ar2-3), and (Ar2-4) represents the positions connected to the two N atoms in formula (M1-1);

[0033] m and p in the structural formula (Ar2-3) each independently and identically or differently represent 0, 1, or 2.

[0034] Scheme 2: The polyarylether polymer according to Scheme 1 above, wherein M1 is any one of the structural moieties derived from the following bisphenol monomer compounds (a), (b), (c), (d), (e) and (f):

[0035]

[0036] Scheme 3: The polyarylether polymer according to Scheme 1 or 2 above, wherein M2 is any one of the structural moieties derived from the following dihalo monomer compounds:

[0037]

[0038]

[0039] wherein Hal represents a halogen element selected from F, Cl, Br or I.

[0040] Scheme 4: The polyarylether polymer according to any one of Schemes 1 to 3 above, wherein M2 is any one of the structural moieties derived from the following difluoro monomer compounds (g), (h) and (i):

[0041] (g) 4,4'-Difluorobenzophenone;

[0042] (h) Furan-2,5-diylbis((4-fluorophenyl)methanone); and

[0043] (i) 4,4'-Difluorodiphenyl sulfone.

[0044] Scheme 5: The polyarylether polymer according to any one of Schemes 1 to 4 above, wherein the polymer has one or more of the following properties:

[0045] The glass transition temperature of the polymer is in the range of about 135 to about 160 °C;

[0046] The homogeneous film formed from the polymer with a thickness in the range of 20 to 40 μm has a tensile strength in the range of about 50 to about 70 MPa; and

[0047] The homogeneous film formed from the polymer has a self-healing efficiency in the range of about 85% to about 95%.

[0048] Scheme 6: A method for preparing the polyarylether polymer according to any one of Schemes 1 to 5 above, wherein the method comprises:

[0049] Under the protection of an inert atmosphere, a bisphenol monomer and a dihalo monomer with a molar ratio in the range of about (0.95 - 1.05):(0.95 - 1.05) are refluxed with water removal in a water-carrying agent and an organic solvent with a volume ratio of about (1.5 - 4):1 in the presence of a carbonate catalyst in an amount of about 1.3 to about 2 times the molar amount of the bisphenol monomer at about 80 to about 160 °C for at least about 3 hours. The water-carrying agent is removed, and the temperature is raised (for example, adjusted to about 100 to about 170 °C) to distill off the remaining water-carrying agent in the reaction system. The temperature is further adjusted to about 120 to about 190 °C, and the reactants are allowed to continue reacting at this temperature for about 2 to about 12 hours to obtain the polyarylether polymer.

[0050] Scheme 7: The preparation method according to Scheme 6 above, wherein the concentrations of the bisphenol monomer and the dihalo monomer in the reaction system are each at least about 0.2 mol / L.

[0051] Scheme 8: The preparation method according to Scheme 6 or 7 above, wherein the water-carrying agent includes one or more of toluene, n-hexane, cyclohexane, benzene, and xylene.

[0052] Scheme 9: The preparation method according to any one of Schemes 6 to 8 above, wherein the carbonate catalyst includes one or more of potassium carbonate, sodium carbonate, lithium carbonate, cesium carbonate, calcium carbonate, sodium bicarbonate, and potassium bicarbonate.

[0053] Scheme 10: The preparation method according to any one of Schemes 6 to 9 above, wherein the organic solvent includes one or more of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, dimethyl sulfoxide, chloroform, and dichloromethane.

[0054] Scheme 11: A self-healing coating comprising the polyarylether polymer according to any one of Schemes 1 to 5 above or the polyarylether polymer prepared by the preparation method according to any one of Schemes 6 to 10 above.

[0055] Scheme 12: Use of the self-healing coating according to Scheme 11 above in the field of flexible electronics.

[0056] Technical effects

[0057] The molecular chain structure of the polyarylether polymer of the present invention simultaneously contains a Schiff base and an aryl ether ketone (and / or sulfone) structure. Through the molecular design of the dynamic Schiff base bond, the polyarylether polymer material is endowed with self-healing ability and recyclability. The polyarylether polymer of the present invention has improved mechanical properties and processing properties while maintaining the thermal properties of traditional polyarylether ketone (and / or sulfone). Therefore, the self-healing coating containing the polyarylether polymer of the present invention can be used in fields such as flexible electronics.

[0058] The method for preparing the polyarylether polymer of the present invention has strong universality, is applicable to the preparation of polyarylether resins from a variety of bisphenol monomers and dihalogen monomers, and has good repeatability.

[0059] In addition, vanillin (i.e., 3-methoxy-4-hydroxybenzaldehyde) used for synthesizing the bisphenol monomer has a wide source and low price, and the synthesis process is mature. It can be prepared at low cost through renewable resources (such as eugenol and ferulic acid) or chemical synthesis methods, and has a large industrial production scale. Moreover, the large-scale production of difluoro monomers such as 4,4'-difluorobenzophenone has been realized in the prior art. In addition, the supply chain of raw materials such as furandicarboxylic acid is concentrated, and the transportation and procurement costs are low. Therefore, the synthesis cost of the present invention can be further reduced. Brief Description of the Drawings

[0060] In order to more clearly illustrate the technical solutions in the specific embodiments of the present invention, the drawings required for the specific embodiments will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0061] Figure 1 It is the infrared spectrum diagram of the polyarylether polymer prepared in Examples 1 to 6 of the present invention.

[0062] Figure 2 It is the differential scanning calorimetry diagram of the polyarylether polymer prepared in Examples 1 to 6 of the present invention.

[0063] Figure 3 It is the thermogravimetric analysis diagram of the polyarylether polymer prepared in Examples 1 to 6 of the present invention. Detailed Description of the Embodiments

[0064] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. The process parameters without specific conditions noted in the following embodiments are usually in accordance with conventional conditions.

[0065] In the ranges disclosed in the present invention, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. The term "about" used in the present invention means that the number it modifies can fluctuate within the range of ±20%, ±15%, ±10%, ±5% or ±2% of that number. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and the individual point values included therein, and between the said individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in the present invention.

[0066] According to the first aspect of the present invention, the present invention provides a polyarylether polymer containing a Schiff base structure in the main chain.

[0067] In the polyarylether polymer of the first aspect of the present invention, the Schiff base structure contained in the main chain refers to a structural part containing a -CR=N- group, where R can be hydrogen or an alkyl group, preferably hydrogen.

[0068] The polyarylether polymer according to the first aspect of the present invention has a main chain structural part represented by the following formula (I):

[0069]

[0070] In the formula (I), n is a number such that the molecular weight of the polyarylether polymer is in the range of about 1.0×10 4 to about 3.0×10 4 Daltons. In some preferred embodiments, the molecular weight of the polyarylether polymer can be, for example, about 1.11×10 4 Daltons, about 1.23×10 4 Daltons, about 1.51×10 4 Daltons, about 1.98×10 4 Daltons, about 2.15×10 4 Daltons or about 2.71×10 4 Daltons. Here, the molecular weight of the polyarylether polymer should not be too high. For example, it should not exceed about 3.0×10 4 Daltons. An excessively high molecular weight may cause the viscosity of the solution formed by the polymer to be too high, making molding and processing difficult and the toughness to decrease; nor should it be too low. For example, it should not be lower than about 1.0×10 4 Daltons, otherwise a homogeneous thin film may not be formed from the polymer.

[0071] In the formula (I), M2 represents any one of the structural parts represented by the following formulas (M2-1), (M2-2) and (M2-3):

[0072]

[0073]

[0074] In some preferred embodiments, M2 represents any one of the structural moieties represented by the following formulas (M2-1-1), (M2-2-1), and (M2-3-1):

[0075]

[0076] In the above formulas (M2-1), (M2-2), (M2-3), (M2-1-1), (M2-2-1), and (M2-3-1), the symbol "*" represents the positions where they are respectively connected to the O atom in formula (I) and the O atom of another adjacent formula (I) structural moiety.

[0077] In the above formula (I), M1 represents a structural moiety represented by the following formula (M1-1):

[0078] *-Ar1-CH=N-Ar2-N=CH-Ar1-*(M1-1)

[0079] In the above formula (M1-1), the symbol "*" represents the positions where they are respectively connected to the O atom in formula (I).

[0080] In the above formula (M1-1), Ar1 represents a group represented by the following formula (II) that can be derived from vanillin, for example:

[0081]

[0082] Wherein, in the above formula (II), the "*" on the bond in the meta position of the methoxy group represents the position connected to the C atom in the Schiff base structure in formula (M1-1), and the "*" on the bond in the ortho position of the methoxy group represents the position connected to the O atom in formula (I).

[0083] In the above formula (M1-1), Ar2 represents a structural moiety represented by any one of the following formulas (Ar2-1), (Ar2-2), (Ar2-3), and (Ar2-4):

[0084]

[0085] In the above formulas (Ar2-1), (Ar2-2), (Ar2-3), and (Ar2-4), the symbol "*" represents the positions connected to the two N atoms in formula (M1-1);

[0086] In m and p in the above structural formula (Ar2-3), each independently of one another and being the same or different, represent 0, 1 or 2, respectively indicating that 0, 1 or 2 of the said trifluoromethyl groups (-CF3) may independently exist on each of the two benzene rings.

[0087] In the above formulas (M2-1), (M2-2), (M2-3), (Ar2-1), (Ar2-2), (Ar2-3) and (Ar2-4), the single bond extending into the benzene ring indicates that the position where the single bond is connected to the benzene ring is at any available position of the benzene ring.

[0088] In a preferred embodiment of the polyarylether polymer according to the first aspect of the present invention, the M1 is any one of the structural moieties derived from the following bisphenol monomer compounds (a), (b), (c), (d), (e) and (f):

[0089]

[0090] In the nucleophilic substitution polycondensation reaction for forming the polyarylether polymer of the present invention, the above bisphenol monomer compounds (a), (b), (c), (d), (e) and (f) first react with a carbonate catalyst to form a phenoxide salt, and the resulting phenoxide salt then reacts with a dihalo monomer to form a σ-complex, and then the halogen atom leaves and an ether bond is formed, thereby gradually generating a high molecular weight polyarylether polymer product.

[0091] In another preferred embodiment of the polyarylether polymer according to the first aspect of the present invention, the M2 is any one of the structural moieties derived from the following dihalo monomer compounds:

[0092]

[0093] wherein Hal represents a halogen element selected from F, Cl, Br or I.

[0094] In a particularly preferred embodiment, the M2 is any one of the structural moieties derived from the following difluoro monomer compounds (g), (h) and (i): (g) 4,4'-difluorobenzophenone; (h) furan-2,5-diylbis((4-fluorophenyl)methanone); and (i) 4,4'-difluorodiphenyl sulfone.

[0095] According to a second aspect of the present invention, the present invention provides a method for preparing a polyarylether polymer containing a Schiff base structure in the main chain as described in the first aspect of the present invention above.

[0096] The preparation method according to the second aspect of the present invention includes, under the protection of an inert atmosphere, reacting a bisphenol monomer compound and a dihalo monomer compound in a molar ratio in the range of about (0.95 - 1.05):(0.95 - 1.05) in the presence of a carbonate catalyst in an amount of about 1.3 to about 2 times the molar amount of the bisphenol monomer in a water-carrying agent and an organic solvent in a volume ratio of about (1.5 - 4):1, and carrying out water reflux at about 80 to about 160 °C for at least about 3 hours. Then, the water-carrying agent is discharged, the temperature is raised to distill off the remaining water-carrying agent in the reaction system, and the temperature is further adjusted to about 120 to about 190 °C, and the reactants are allowed to continue reacting at this temperature for about 2 to about 12 hours to obtain the polyarylether polymer.

[0097] In the above preparation method, the bisphenol monomer compound and the dihalo monomer compound can be, for example, one or more of the bisphenol monomer compounds (a), (b), (c), (d), (e), and (f) and one or more of the difluoro monomer compounds (g), (h), and (i) described in the paragraph of the polyarylether polymer according to the first aspect of the present invention above. Here, the molar ratio between the bisphenol monomer compound and the dihalo monomer compound is preferably in the range of about (0.95 - 1.05):(0.95 - 1.05), for example, about 1:1. Here, the molar ratio between the two monomer compounds should not differ too much. For example, it should not exceed 1.05:0.95 or be lower than 0.95:1.05, otherwise it may easily lead to reaction termination.

[0098] In the above preparation method, the molar amount of the carbonate catalyst should be about 1.3 to about 2 times the molar amount of the bisphenol monomer. Here, the amount of the catalyst should not be too high. For example, it should not exceed about 2 times the molar amount of the bisphenol monomer because the solubility of the catalyst in the organic solvent is limited, and too much catalyst may not be completely removed during the subsequent removal process; nor should it be too low. For example, it should not be lower than about 1.3 times the molar amount of the bisphenol monomer. A catalyst with an amount lower than this may not form sufficient phenoxide, resulting in insufficient activity and difficulty in the polymerization reaction.

[0099] In the above preparation method, the volume ratio of the water-carrying agent and the organic solvent should be about (1.5 - 4):1, for example, about 1.8:1, about 2:1, about 2.5:1, about 3:1, or about 3.5:1. Here, the amount of the water-carrying agent should not be too much. For example, it should not exceed about 4 times the volume of the organic solvent, otherwise the water-carrying agent cannot be completely removed during the subsequent distillation of the water-carrying agent, and the residual water-carrying agent is wrapped in the polymer and is difficult to remove; nor should it be too little. For example, it should not be lower than about 1.5 times the volume of the organic solvent, otherwise it may lead to insufficient removal of the water in the system, and the presence of water may cause hydrolysis of the halide and breakage of the molecular chain.

[0100] In the above preparation method, the temperature of the water-carrying reflux is in the range of about 80 to about 160 °C. For example, it can be about 90 °C, about 100 °C, about 110 °C, about 120 °C, about 130 °C, about 135 °C, about 140 °C or about 150 °C. The temperature of the water-carrying reflux should not be too high. For example, it should not exceed about 150 °C, otherwise it may cause the deterioration of the reactants in the polymerization system; nor should it be too low. For example, it should not be lower than about 90 °C, otherwise the water-carrying agent may not be azeotropic with water, resulting in the inability to carry out the water in the reaction system.

[0101] In the above preparation method, the duration of the water-carrying reflux is at least about 3 hours. Here, the duration should not be shorter than about 3 hours, otherwise there may be residual water in the reaction system, and the residual water will cause the hydrolysis of the halide and the breakage of the molecular chain, and the target molecular weight product cannot be obtained.

[0102] In the above preparation method, after the water-carrying reflux, it is necessary to raise the temperature to distill out the remaining water-carrying agent in the reaction system. For example, in some exemplary embodiments of the present invention, the temperature can be adjusted to about 100 to about 170 °C, such as about 120 °C, about 130 °C, about 145 °C, about 155 °C or about 160 °C to distill out the remaining water-carrying agent in the reaction system as much as possible.

[0103] In the above preparation method, after removing the water-carrying agent, the temperature needs to be further adjusted to about 120 to about 190 °C, such as about 130 °C, about 140 °C, about 150 °C, about 160 °C, about 170 °C or about 180 °C, and the reactants are allowed to continue to react at this temperature for about 2 to about 12 hours, such as about 3 hours, about 4 hours, about 5 hours, about 6 hours, about 7 hours, about 8 hours, about 9 hours, about 10 hours or about 11 hours. Here, the reaction temperature should not be too high. For example, it should not exceed about 190 °C, otherwise the reaction may occur violently, generating gel, and the reaction is not easy to control; nor should it be too low. For example, it should not be lower than about 120 °C, otherwise the reaction activity may not be sufficient and the reaction cannot proceed. In addition, the reaction duration should not be too long. For example, it should not exceed about 12 hours, otherwise depolymerization may occur, resulting in a decrease in the polymer molecular weight; nor should it be too short. For example, it should not be shorter than about 2 hours, otherwise the molecular weight of the generated polymer is too low to form a film.

[0104] In a preferred embodiment of the above preparation method according to the second aspect of the present invention, the respective concentrations of the bisphenol monomer and the dihalo monomer in the reaction system should be at least about 0.2 mol / L. Here, too small a concentration of the reactants, such as a monomer concentration below about 0.2 mol / L, may cause the reaction not to proceed or the reaction time to be too long.

[0105] In another preferred embodiment of the preparation method according to the second aspect of the present invention, the function of the water-carrying agent is to remove the water carried into the reaction system by the added raw materials and the water generated in the reaction system. In the reaction system, the bisphenol monomer compound and the carbonate react first to form phenoxide and carbonic acid, and the carbonic acid may decompose into carbon dioxide and water. The presence of water may cause hydrolysis of the halide and cleavage of the molecular chain, so it is necessary to remove the water in the reaction system as much as possible. The principle of water-carrying is to use the water-carrying agent to form an azeotrope with water. The water-carrying agents that can be used in the preparation method of the present invention include, for example, but are not limited to, one or more of toluene, n-hexane, cyclohexane, benzene, and xylene.

[0106] In another preferred embodiment of the preparation method according to the second aspect of the present invention, the carbonate catalyst may include, for example, but is not limited to, one or more of potassium carbonate, sodium carbonate, lithium carbonate, cesium carbonate, calcium carbonate, sodium bicarbonate, and potassium bicarbonate.

[0107] In another preferred embodiment of the preparation method according to the second aspect of the present invention, the organic solvent is not particularly limited as long as it can dissolve the reactants and enable the reaction to proceed sufficiently. For example, in some exemplary embodiments of the present invention, the organic solvent may include, but is not limited to, one or more of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, dimethyl sulfoxide, chloroform, and dichloromethane.

[0108] In addition, the polyarylether polymer according to the first aspect of the present invention and the polyarylether polymer prepared by the preparation method according to the second aspect of the present invention preferably have one or more of the following properties:

[0109] The glass transition temperature of the polymer is in the range of about 135 to about 160 °C;

[0110] The homogeneous film formed by the polymer with a thickness in the range of 20 to 40 μm has a tensile strength in the range of about 50 to about 70 MPa; and

[0111] The homogeneous film formed by the polymer has a self-healing efficiency in the range of about 85% to about 95%.

[0112] According to the third aspect of the present invention, the present invention provides a self-healing coating, which comprises the polyarylether polymer according to the first aspect of the present invention as described above or the polyarylether polymer prepared by the preparation method according to the second aspect of the present invention as described above.

[0113] According to the fourth aspect of the present invention, the present invention further provides the use of the self-healing coating according to the third aspect of the present invention as described above in the field of flexible electronics.

[0114] The present invention will be further described in detail below with reference to specific examples and comparative examples.

[0115] Unless otherwise specified, the chemical reagents used in the following examples are all analytically pure chemical reagents obtained commercially.

[0116] The bisphenol monomer compounds (a) and (b) used in the examples were synthesized by the inventors according to the following literature: Zhimin Wang et al., Plant-Derived p-Hydroxyphenylacrylic Acid-Derived Epoxy Resins Exhibit Excellent Flame Retardancy, Hydrophobicity, Degradability, and Low Dielectric Loss After Curing With Bio-Based Fluorinated Schiff Bases, POLYMER DEGRADATION AND STABILITY 2023, 209, 110270. Specifically, it includes:

[0117] First, about 3.80 g of vanillin (about 25 mmol) was dissolved in about 50 mL of ethanol (in a 100 mL three-necked flask); 2,2'-bis(trifluoromethyl)benzidine (3.20 g, 10 mmol) was slowly added. After stirring at about 40 °C for about 1 hour, the reaction system of the solution was heated to about 80 °C and maintained for about 5 hours (N2 atmosphere). Then the reaction system was cooled to room temperature, and the product was precipitated into deionized water. The product powder gradually precipitated, and it was washed repeatedly with deionized water 3 times. The solid was collected by suction filtration, and the obtained solid was dried in an oven at about 120 °C for about 24 hours to obtain the bisphenol monomer (a) required for polymerization.

[0118] Compound (b) was synthesized in a process similar to the synthesis of bisphenol monomer (a) above, except that 2,2'-bis(trifluoromethyl)benzidine was replaced with 4-(4-aminophenyl)-3,5-bis(trifluoromethyl)aniline.

[0119] The bisphenol monomer compounds (c), (d), (e) and (f) used in the examples were synthesized by the inventors according to the following literature: X. Zhang et al., High-Performance Biobased Vinyl Ester Resin with Schiff Base Derived from Vanillin, ACS APPL. POLYM. MATER., 4 (2022), pp. 2604-2613. Specifically, it includes:

[0120] Vanillin (about 3.3473 g, about 2 mmol) was added to a 100 ml three-necked flask, about 50 ml of absolute ethanol was added, and the mixture was stirred at room temperature until completely dissolved. Subsequently, about 2.0009 g (about 10 mmol) of 4,4'-diaminodiphenyl ether was added in portions. Under nitrogen protection, stirring was continued at room temperature for about 1 hour to form a homogeneous solution, and then the temperature was raised to about 80 °C and reacted for about 6 hours. After the reaction was completed, the reaction was cooled to room temperature, and the product was precipitated in deionized water. The product powder gradually precipitated out, and it was washed 3 times repeatedly with deionized water. The solid was collected by suction filtration, and the obtained solid was dried in an oven at about 120 °C for about 24 hours to obtain the bisphenol monomer (d) required for polymerization.

[0121] Compounds (c), (e), and (f) were synthesized by a process similar to the above synthesis of bisphenol monomer (d), except that 4,4'-diaminodiphenyl ether was replaced with 1,3-bis(4'-aminophenoxy)benzene, m-phenylenediamine, and p-phenylenediamine, respectively.

[0122] Vanillin, 2,2'-bis(trifluoromethyl)benzidine, 4-(4-aminophenyl)-3,5-bis(trifluoromethyl)aniline, 1,3-bis(4'-aminophenoxy)benzene, and 4,4'-diaminodiphenyl ether used in the above synthesis were all commercially purchased from Shanghai Macklin Biochemical Co., Ltd.; p-phenylenediamine and m-phenylenediamine were all commercially purchased from Shanghai Aladdin Reagent Co., Ltd.

[0123] The difluoro monomer compound (h) used in the examples was synthesized by the inventors according to the following literature: Kanetaka, Y et al., Preparation of Poly(ether ketone)s Derived from 2,5-Furandicarboxylic Acid by Polymerization in Ionic Liquid, MACROMOLECULES 49, 1252–1258 (2016). Specifically, it includes:

[0124] Synthesis of intermediate 2,5-furandicarbonyl chloride FDCC: 2,5-furandicarboxylic acid FDCA (about 140.00 g, about 0.90 mol), SOCl2 (about 280 ml), and a few drops of DMF were added to a three-necked flask equipped with a mechanical stirrer and a condenser reflux device, and the temperature was slowly raised to about 80 °C with an oil bath and refluxed for about 4 hours. Then, the excess SOCl2 was removed by distillation under reduced pressure. After the SOCl2 was completely removed, suction filtration was carried out with an oil pump, and the sublimated FDCC was collected. The yield was about 89.2%.

[0125] Synthesis of 2,5-bis(4-fluorobenzoyl)furan BFBF: Add FDCC (about 173.06 g, about 0.90 mol) and fluorobenzene (about 259.50 g, about 2.70 mol) into a three-necked flask equipped with a nitrogen inlet and a tail gas treatment device. After complete dissolution, transfer the system to an ice-water bath and slowly add AlCl3 (about 336.01 g, about 2.52 mol) in portions. After the system stabilizes, remove the ice bath and gradually heat up to about 70 °C and reflux for about 12 hours or more. After stopping the reaction, cool the system to room temperature and then pour it into a methanol solution. Filter out the precipitate, dry it, and recrystallize it with toluene and n-hexane to obtain the pale yellow crystal BFBF (h). The yield is about 76.5%.

[0126] The 2,5-furandicarboxylic acid used in the above synthesis was commercially available from Shanghai TCI Chemical Industry Development Co., Ltd.; and fluorobenzene was commercially available from Shanghai Aladdin Reagent Co., Ltd.

[0127] The difluoro monomer compound (i) used in the examples was commercially available from Shanghai Macklin Biochemical Co., Ltd. with a purity of about 98%; the difluoro monomer compound (g) was commercially available from Wuhan Yuancheng Gongchuang Technology Co., Ltd. with a purity of about 98%.

[0128] Examples 1 to 6: General preparation process of polyarylether polymers containing Schiff base structure in the main chain

[0129] Under nitrogen protection, add about 5 mmol of bisphenol monomer, about 5 mmol of difluoro monomer and about 6.58 mmol of potassium carbonate (about 0.91 g) as a catalyst into a 100 mL three-necked flask connected with a mechanical stirrer, a water separator, an inlet pipe and a condenser. Add about 10 mL of N-methylpyrrolidone (NMP) as a solvent and about 15 mL of toluene as a water-carrying agent.

[0130] Gradually increase the temperature of the obtained reaction mixture and reflux with water at this temperature (water-carrying temperature) for about 3 hours to ensure that there is no residual water in the reaction system finally, and then drain off the water-carrying agent.

[0131] Further heat the reaction mixture to the distillation temperature to remove the residual water-carrying agent in the system.

[0132] Heat the reaction mixture to the reaction temperature and maintain it at this temperature for a period of time (reaction time).

[0133] After the reaction stopped, NMP solvent was added to the mixture in the three-necked flask to dilute the reactants to a concentration in the range of about 15 to 20 wt%, and then poured into about 2 L of boiling deionized water for precipitation, thereby precipitating a crude solid polymer. The crude polymer was washed thoroughly with boiling deionized water, and then filtered to obtain the polymer solid. The polymer solid was dried in an ordinary pressure oven for about 10 hours and then in a vacuum oven to obtain the dried polyarylether polymer of the embodiment of the present invention.

[0134] The specific process conditions in the preparation processes in Examples 1 to 6 are summarized in Table 1 below.

[0135] Table 1:

[0136]

[0137] The solubility of the polyarylether polymers containing Schiff base structures in the main chain prepared in Examples 1 to 6 of the present invention in different solvents (NMP, N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), chloroform and dichloromethane) was measured. The test results are shown in Table 2 below.

[0138] Table 2

[0139] Example Number NMP DMAc DMF THF DMSO Chloroform Dichloromethane Example 1 ++ +- +- ++ - ++ ++ Example 2 ++ +- +- ++ - ++ - Example 3 ++ ++ ++ ++ + ++ - Example 4 ++ ++ ++ ++ + ++ - Example 5 ++ ++ ++ ++ ++ +- - Example 6 ++ ++ ++ - + + +-

[0140] In Table 2 above,

[0141] ++ indicates dissolution at room temperature;

[0142] + indicates dissolution under the condition of heating the solvent to boiling;

[0143] +- indicates partial dissolution under the condition of heating the solvent to boiling;

[0144] - indicates no dissolution even under the condition of heating the solvent to boiling.

[0145] It can be seen from Table 2 above that the polyarylether polymers prepared in Examples 1 to 6 of the present invention have good solubility in common organic solvents for film preparation, so that polyarylether homogeneous membranes can be conveniently prepared from them, providing good conditions for the dissolution, preparation and processing of the polymers.

[0146] Measure the mechanical properties and self-healing properties of the polyarylether polymers prepared in Examples 1 to 6 of the present invention. Specifically, it includes: dissolving the polyarylether polymers prepared in Examples 1 to 6 of the present invention in NMP, and then making a polymer homogeneous film with a thickness in the range of about 20 to about 40 μm, and testing the tensile properties and self-healing properties of the prepared homogeneous film. The performance test of the homogeneous film is carried out on an Instron 5869 universal testing machine produced by Instron Corporation. Referring to the ASTM D882-2018 standard, the polymer film is cut into a size of about 6 mm × 100 mm, the tensile rate is about 5 mm / min, and the test temperature is about 22 °C.

[0147] In addition, measure the infrared spectrum (FT-IR) of the polyarylether polymers containing Schiff base structure prepared in Examples 1 to 6 of the present invention. For the specific infrared spectra, refer to the attached Figure 1 , Figure 1 in the present invention specification, where the abscissa is the wavenumber. The measurement process uses a Thermo Nicolet IS50 infrared spectrometer, and the reflection spectroscopy test mode is adopted. Before measurement, place the test sample in a vacuum oven at about 100 °C and dry it for more than 12 hours to exclude the interference of solvents such as water on the test. From Figure 1 the peaks of characteristic structures can be seen to appear. For example, the infrared absorption peak of the imine bond appears at a wavenumber of 1650 cm -1 , and the absorption peak of the ether bond appears at 1250 cm -1 . Thus, it can be determined that the polyarylether polymers with the desired structure of the present invention are obtained through Examples 1 to 6 of the present invention.

[0148] Use a METTLER DSC822 differential scanning calorimeter to test the glass transition temperature (T g ) of the polyarylether polymers prepared in Examples 1 to 6 of the present invention. For the specific test result spectra, refer to the attached Figure 2 , Figure 2 in the present invention specification, where the abscissa is the temperature and the ordinate is the exotherm. During the measurement process, set the nitrogen flow rate to about 50 ml / min, the heating rate to about 10 °C / min, and the test range to about 50 to about 300 °C. Before the test, place the test sample in a vacuum oven at about 100 °C and dry it for about 12 hours or more to exclude the interference of solvents such as water on the test.

[0149] Carry out thermogravimetric analysis of the polyarylether polymers prepared in Examples 1 to 6 of the present invention on a METTLER TGA / SDTA851. For the specific analysis result spectra, refer to the attached Figure 3 , Figure 3The abscissa therein is Temperature and the ordinate is Residual mass. During the said test, the test is carried out in a nitrogen atmosphere (gas flow rate is about 50 mL / min) with a heating rate of about 10 °C / min. Before the test, the test sample is placed in a vacuum oven at about 100 °C and dried for more than about 12 hours to exclude the interference of solvents such as water on the test.

[0150] Gel permeation chromatography (GPC) tests of the polyarylether polymers prepared in Examples 1 to 6 of the present invention are carried out on an Agilent PL-GPC 50 instrument to obtain their number average molecular weights, wherein NMP is used as the solvent.

[0151] The results obtained from the above tests are shown in Table 3 below.

[0152] Table 3:

[0153]

[0154] It can be seen from the performance test results in Table 3 above that the polyarylether polymers prepared in Examples 1 to 6 of the present invention have good chemical stability (the glass transition temperature is in the range of 137 to 160 °C, and the decomposition temperature Td,5% reaches above 394 °C), good mechanical properties (the tensile strength is in the range of 56 to 70 MPa), and excellent self-healing properties (the self-healing efficiency is in the range of 85% to 95%). The good mechanical properties can enable the polyarylether polymer of the present invention to be used as a structural material to withstand high loads and repeated stresses, while the excellent self-healing ability can enable the polyarylether polymer of the present invention to extend the service life of the material, reduce maintenance costs, and reduce waste.

[0155] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions required to be protected by the present invention.

Claims

1. A polyarylether polymer containing a Schiff base structure in the main chain, characterized in that, The polyarylether polymer has a main chain structural part represented by the following formula (I): In the formula (I), n is a number such that the molecular weight of the polyarylether polymer is in the range of 1.0×10 4 to 3.0×10 4 Daltons; M2 represents any one of the structural parts represented by the following formulas (M2-1), (M2-2) and (M2-3): Wherein, in the formulas (M2-1), (M2-2) and (M2-3), the symbol "*" respectively represents the positions where they are connected to the O atom in the formula (I) and the O atom in another adjacent structural part of the formula (I); M1 represents the structural part represented by the following formula (M1-1): *-Ar1-CH=N-Ar2-N=CH-Ar1-*(M1-1) Wherein, in the formula (M1-1), the symbol "*" respectively represents the positions where they are connected to the O atom in the formula (I); Ar1 represents the group represented by the following formula (II): Wherein, in the formula (II), the "*" on the bond in the meta position of the methoxy group represents the position where it is connected to the C atom in the Schiff base structure in the formula (M1-1), and the "*" on the bond in the ortho position of the methoxy group represents the position where it is connected to the O atom in the formula (I); Ar2 represents any one of the structural parts represented by the following formulas (Ar2-1), (Ar2-2), (Ar2-3) and (Ar2-4): Wherein, in the formulas (Ar2-1), (Ar2-2), (Ar2-3) and (Ar2-4) the symbol "*" represents the positions where they are connected to the two N atoms in the formula (M1-1); in the structural formula (Ar2-3), m and p, each independently of the other and being the same or different, represent 0, 1 or 2.

2. The polyarylether polymer according to claim 1, characterized in that, The M1 is any one of the structural parts derived from the following bisphenol monomer compounds (a), (b), (c), (d), (e) and (f):

3. The polyarylether polymer according to claim 1, wherein The M2 represents any one of the structural parts represented by the following formulas (M2-1-1), (M2-2-1) and (M2-3-1):

4. The polyarylether polymer according to claim 1, characterized in that, The M2 is any one of the structural parts derived from the following difluoromonomer compounds (g), (h) and (i): (g) 4,4'-Difluorobenzophenone; (h) Furan-2,5-diylbis((4-fluorophenyl)methanone); and (i) 4,4'-Difluorodiphenyl sulfone.

5. The polyarylether polymer according to any one of claims 1 to 4, characterized in that, The polymer has one or more of the following properties: The glass transition temperature of the polymer is in the range of 135 to 160 °C; The homogeneous film formed from the polymer with a thickness in the range of 20 to 40 μm has a tensile strength in the range of 50 to 70 MPa; and The homogeneous film formed from the polymer has a self-healing efficiency in the range of 85% to 95%.

6. A method for preparing a polyarylether polymer according to any one of claims 1 to 5, characterized in that, The method includes: Under the protection of an inert atmosphere, a bisphenol monomer and a dihalogen monomer with a molar ratio in the range of (0.95 - 1.05):(0.95 - 1.05) are refluxed with water removal for at least 3 hours at a temperature of 80 to 160 °C in a water-carrying agent and an organic solvent with a volume ratio of (1.5 - 4):1 in the presence of a carbonate catalyst in an amount of 1.3 to 2 times the molar amount of the bisphenol monomer. The water-carrying agent is discharged, the temperature is raised to distill off the remaining water-carrying agent in the reaction system, and the temperature is further adjusted to 120 to 190 °C to allow the reactants to continue reacting at this temperature for 2 to 12 hours to obtain the polyarylether polymer.

7. The method according to claim 6, characterized in that The concentration of each of the bisphenol monomer and the dihalogen monomer in the reaction system is at least 0.2 mol / L.

8. The method according to claim 6 or 7, wherein the water-carrying agent includes one or more of toluene, n-hexane, cyclohexane, benzene, and xylene; and / or the carbonate catalyst includes one or more of potassium carbonate, sodium carbonate, lithium carbonate, cesium carbonate, calcium carbonate, sodium bicarbonate, and potassium bicarbonate; and / or the organic solvent contains one or more of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, dimethyl sulfoxide, chloroform, and dichloromethane.

9. A self-healing coating comprising the polyarylether polymer according to any one of claims 1 to 5.

10. Use of the self-healing coating according to claim 9 in the field of flexible electronics.

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