Aromatic guanidino amino acid-based remodelable polyguanidino urea material as well as preparation method and application thereof

Abstract

The invention discloses a remodelable polyguanidine urea material based on aromatic guanidyl amino acid as well as a preparation method and application thereof, and relates to the technical field of high polymer materials. The preparation method comprises the following steps: uniformly mixing a reaction system containing an aromatic guanidino amino acid monomer, a polyfunctional isocyanate compound and a solvent, firstly carrying out pre-reaction, removing the solvent, and then curing to obtain the remodelable polyguanidino urea material based on the aromatic guanidino amino acid. Aromatic guanidyl amino acid containing guanidyl and carboxyl functional groups reacts with polyfunctional isocyanate to form a guanidyl urea bond and an amido bond, so that the dynamic covalent polymer network structure material is formed, has excellent thermal stability and mechanical properties, is high in dynamic exchange speed, and can be applied to the field of chemical engineering. Rapid remodeling and reprocessing can be realized through a simple hot pressing method; meanwhile, the method has the characteristics of simple preparation method, no need of a catalyst through the action of multistage hydrogen bonds and non-covalent bonds in the structure, mild reaction conditions, strong operability, easiness in realization of industrial production and great application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a method for preparing a dynamic covalent polymer network material composed of aromatic guanidine amino acids and multifunctional isocyanates, and specifically to a remodelable polyguanidine urea based on aromatic guanidine amino acids, and a preparation method and application thereof. Background Art

[0002] Thermosetting polymers are widely used in many fields due to their excellent mechanical properties, dimensional stability and chemical stability. However, their internal cross-linked network leads to problems such as difficulty in damage repair, complex waste disposal and high recycling costs. In recent years, by introducing dynamic covalent bonds as cross-linking bonds, the advantages of traditional thermosetting polymers are retained, and dynamic reorganization can be performed under specific conditions, thus providing a new way for the recycling, reprocessing and self-repair of materials, showing great potential in the direction of circular economy and sustainable development.

[0003] With the continuous advancement of science and technology, complex usage scenarios have put forward more and higher requirements on the performance of materials. Polyurea is an elastomeric substance generated by the reaction of isocyanate components and amino compound components, which has the characteristics of corrosion resistance, waterproofness, and wear resistance. The introduction of rigid benzene ring structure into polyurea thermosetting resin can improve the solvent resistance and mechanical properties of the material, and at the same time has the characteristics of rapid curing, excellent heat resistance, and corrosion resistance, which is expected to show unique advantages in waterproof materials, anti-corrosion pipelines, national defense and military industries. Xin et al. used tetrakis (4-aminophenyl) methane and toluene diisocyanate as raw materials, and polymerized at high temperature on the alkane-ionic liquid interface to prepare a solvent-resistant and heat-resistant all-aromatic polyurea material (ACS Materials Lett. 2024, 6, 5, 1897-1905). However, due to the structural design of the all-aromatic, the reaction needs to be carried out under specific conditions, the preparation process is complicated, and the material does not contain dynamic bonds, and reprocessing and reuse cannot be achieved.

[0004] Therefore, it is a problem that still needs to be solved to provide a dynamic bond network polymer based on aromatic polyurea, especially to construct a polyurea material with high strength and rapid remodeling under simple process conditions and without adding catalysts.

[0005] Based on the problems existing in the prior art, the present invention has made further technical improvements. The present invention provides a method for preparing a dynamic covalent polymer network material composed of aromatic guanidine amino acids and multifunctional isocyanates, and a remodelable polyguanidine urea material based on aromatic guanidine amino acids is prepared. Summary of the invention

[0006] In order to overcome the deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide a remodelable polyguanidine urea based on aromatic guanidine amino acids and a preparation method and application thereof. Through the multi-level hydrogen bonds and non-covalent bonds in the structure, the reaction does not require the use of a catalyst, the preparation method is simple, the operability is strong, and it is easy to promote and apply industrialization. It is a new method that can achieve a balance between the mechanical strength of the dynamic covalent polymer network and the network exchange rate.

[0007] To achieve the above objectives, the present invention provides the following technical solutions.

[0008] One aspect of the present invention provides a method for preparing a remodelable polyguanidine urea material based on aromatic guanidine amino acids, wherein an aromatic guanidine amino acid monomer, a multifunctional isocyanate compound, and a solvent are uniformly mixed to form a reaction system, and after a pre-reaction, the solvent is removed and solidified to obtain a remodelable polyguanidine urea material.

[0009] Preferably, an aromatic guanidine amino acid containing guanidine and carboxyl functional groups reacts with a multifunctional isocyanate to form guanidine urea bonds and amide bonds, thereby forming a polyguanidine urea material having a dynamic covalent polymer network structure, wherein the dynamic covalent polymer network structure is formed by the non-covalent interactions formed by the multi-level hydrogen bonds and π-π stacking between molecules within the material and between the introduced aromatic structures and guanidine urea structures.

[0010] Furthermore, the guanidine urea structure and the amide structure form hydrogen bonds between the molecules of the guanidine urea, and the hydrogen bonding effect is more conducive to the rapid exchange of the dynamic covalent polymer network, thereby enabling the polyguanidine urea material to be reshaped in a shorter time.

[0011] Preferably, the aromatic guanidine amino acid monomer is a guanidine carboxylic acid compound containing an aromatic structure, a guanidine group and a carboxyl functional group.

[0012] More preferably, the aromatic guanidine amino acid monomer includes but is not limited to any one or more combinations of guanidine benzoic acid, 4-guanidine-2-methoxybenzoic acid, and 4-(3-ureaguanidine)benzoic acid.

[0013] Preferably, the multifunctional isocyanate compound includes but is not limited to any one of pentamethylene isocyanate, hexamethylene diisocyanate, L-lysine diisocyanate, 1,5-pentamethylene diisocyanate, and hexaethylene diisocyanate trimer, or a combination of two or more thereof.

[0014] Preferably, the solvent includes water, and a mixture consisting of any one or a combination of several of ethanol, dimethyl sulfoxide, and N,N-dimethylformamide.

[0015] Preferably, in the reaction system, the ratio of the sum of the moles of guanidine group, carboxyl group and water to the mole of isocyanate group is 1:(1-1.5), and the ratio of the moles of water to the organic solvent is 1:50-200.

[0016] Preferably, the pre-reaction comprises reacting at 90-150° C. for 0.5-2 h.

[0017] Preferably, the removing of the solvent comprises carrying out the process under vacuum at 65 to 90° C. for 0.5 to 2 h.

[0018] Preferably, the curing is gradient temperature curing.

[0019] Preferably, the curing condition is 110-170°C for 1-3h. It can be understood that, when gradient temperature rise curing is adopted, the curing condition of each time should be within the above curing condition range, and the curing temperature of the latter time should be higher than the curing temperature of the previous time. For example, when gradient temperature rise curing is adopted, the temperature of the second curing is higher than the temperature of the first curing, and the temperature of the third curing is higher than the temperature of the second curing; in particular, the temperature of the first curing is not higher than 150°C.

[0020] Preferably, the curing is performed 2 to 3 times.

[0021] As one of the purposes of the invention, the present invention also provides a remodelable polyguanidine urea material, which is prepared by the above-mentioned preparation method; the remodelable polyguanidine urea material has a dynamic covalent polymer network structure composed of guanidine urea bonds and amide bonds.

[0022] Preferably, the remodelable polyguanidine urea material can be remodeled by hot pressing at 115 to 155° C. for 5 to 60 minutes.

[0023] Preferably, the remodelable polyguanidine urea material has a glass transition temperature of 110 to 150° C., an initial thermal degradation temperature of 230 to 275° C., a Young's modulus of 1020 to 1750 MPa, and a tensile strength of 40.1 to 131.7 MPa.

[0024] As one of the purposes of the invention, the present invention also provides the application of the aforementioned remodelable polyguanidine urea material in multiple fields such as waterproof materials, anti-corrosion pipelines, national defense and military industry.

[0025] The technical effects of the technical solution of the present invention are as follows:

[0026] 1. The present invention prepares high-performance, remodelable guanidine urea materials through aromatic guanidine amino acids and multifunctional isocyanates. In terms of structural design, on the one hand, through the introduction of aromatic structures and guanidine urea structures, multi-level hydrogen bonds within the material and between molecules and π-π stacking between molecules form non-covalent interactions, thereby realizing the enhancement of mechanical properties by the dynamic covalent polymer network. On the other hand, the guanidine urea structure and the amide structure form hydrogen bonds between the molecules of the guanidine urea material, which is conducive to the rapid exchange of the dynamic covalent polymer network, so that the material can be remodeled in a relatively short time. The aromatic guanidine amino acid remodelable polyguanidine urea material prepared in this way not only has excellent thermodynamic stability and mechanical properties, but also can realize self-catalytic rapid remodeling processing.

[0027] 2. The method for preparing the polyurea material provided by the technical solution of the present invention has the advantages of being simple and not requiring the use of a catalyst, and is highly operable and easy to implement. It is a new method for achieving a balance between the mechanical strength of a dynamic covalent polymer network and the network exchange rate, and is suitable for large-scale industrial promotion and production. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 The mechanical properties of the remodelable polyguanidine urea material based on aromatic guanidine amino acid prepared in Example 1 of the present invention are characterized.

[0030] Figure 2 This is a photograph of the remodeled polyguanidine urea material based on aromatic guanidine amino acid prepared in Example 1 of the present invention after being remodeled. DETAILED DESCRIPTION

[0031] To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention is clearly and completely described. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of the present invention.

[0032] The disclosures of all patent and non-patent literature cited herein are incorporated herein by reference in their entirety.

[0033] As used in the invention, the terms "comprises," "includes," "contains," "covers," "has," "with," or any other variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, article, or apparatus that includes a list of elements need not be limited to only those elements, but may include other elements that are not explicitly listed or that are inherent to the process, method, article, or apparatus. In addition, unless expressly indicated to the contrary, "or" refers to an inclusive "or" rather than an exclusive "or." For example, conditions A or B satisfy any of the following: A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), and both A and B are true (or exist). The phrase "one or more" is intended to cover non-exclusive inclusions. For example, one or more of A, B, and C, means any of the following: A alone, B alone, C alone, a combination of A and B, a combination of B and C, a combination of A and C, or a combination of A, B, and C.

[0034] In addition, "a" or "an" is used to describe the elements and components described herein. This is done only for convenience and to provide a general sense of the scope of the invention. This description should be understood to include one or at least one, one or at least one, and the singular also includes the plural, unless it is obvious that it is intended otherwise.

[0035] The present invention prepares a remodelable polyguanidine urea material through aromatic guanidine amino acids and multifunctional isocyanates, has excellent thermal and mechanical properties, can achieve self-catalytic rapid remodeling processing, has a simple preparation method, does not require the use of catalysts, has strong operability, is easy to implement, and is a new method for achieving a balance between the mechanical strength of a dynamic covalent polymer network and the network exchange rate.

[0036] The present invention provides a method for preparing a remodelable polyguanidine urea material based on an aromatic guanidine amino acid, which comprises: firstly performing a pre-reaction on a uniformly mixed reaction system containing an aromatic guanidine amino acid monomer, a multifunctional isocyanate compound and a solvent, and then performing curing after removing the solvent to obtain a remodelable polyguanidine urea material based on an aromatic guanidine amino acid.

[0037] Aromatic guanidine amino acids containing guanidine and carboxyl functional groups react with multifunctional isocyanates to form guanidine urea bonds and amide bonds to obtain remodelable polyguanidine urea materials. Due to the introduction of aromatic and guanidine urea structures, multi-level hydrogen bonds within the material and between molecules and π-π stacking between molecules form non-covalent interactions, which enhance the mechanical properties of the dynamic covalent polymer network. In addition, the guanidine urea structure and the amide structure form hydrogen bonds between the molecules of the guanidine urea material, which is conducive to the rapid exchange of the dynamic covalent polymer network, so that the material can be remodeled in a short time. The method for preparing this material is not only simple and easy, but also does not require the addition of any catalyst, which greatly simplifies the production process. The prepared aromatic guanidine amino acid remodelable polyguanidine urea material exhibits excellent thermal stability and mechanical properties, and has self-catalytic ability, which can be quickly remodeled. It provides a new solution for the polyurea dynamic covalent polymer network, achieving a good balance between mechanical strength and network renewal speed.

[0038] In some embodiments, the aromatic guanidine-containing amino acid monomer includes but is not limited to any one or a combination of two or more aromatic guanidine carboxylic acid compounds containing both guanidine and carboxyl functional groups, such as guanidine benzoic acid, 4-guanidine-2-methoxybenzoic acid, and 4-(3-ureaguanidine)benzoic acid.

[0039] In some embodiments, the multifunctional isocyanate compound includes but is not limited to any one of pentamethylene isocyanate, hexamethylene diisocyanate, L-lysine diisocyanate, 1,5-pentamethylene diisocyanate, and hexaethylene diisocyanate trimer, or a combination of two or more thereof.

[0040] In some embodiments, the solvent includes water, and any one or a combination of two or more of solvents such as ethanol, dimethyl sulfoxide, and N,N-dimethylformamide.

[0041] In some embodiments, the aromatic guanidine amino acid monomer, the multifunctional isocyanate compound and the solvent are uniformly mixed to form the uniformly mixed reaction system;

[0042] The embodiment of the present invention also provides a remodelable polyguanidine urea material based on aromatic guanidine amino acid prepared by the aforementioned method, which has excellent mechanical properties and the function of rapid remodeling processing.

[0043] The molar ratio of the sum of the guanidine group, the carboxyl group and the water to the cyanate group in the uniformly mixed reaction system is 1:(1-1.5), and the molar ratio of water to the solvent is 1:50-200.

[0044] In some preferred embodiments, the preparation method comprises: allowing the uniformly mixed reaction system to undergo a pre-reaction at 90 to 150° C. for 0.5 to 2 hours.

[0045] In some preferred embodiments, the uniformly mixed reaction system is placed in a vacuum oven at 65-90° C. for 0.5-2 h to remove the solvent.

[0046] Furthermore, the curing process is one or more times of curing at 110-170° C. for 1-3 hours.

[0047] Furthermore, the remodelable polyguanidine urea material of the aromatic guanidine amino acid is prepared by curing in the absence of a catalyst through the multi-level hydrogen bonds and non-covalent bonds in the structure, by containing guanidine and carboxyl amino acids and multifunctional isocyanate compounds.

[0048] The aromatic guanidine amino acid remodelable polyguanidine urea material prepared by the present invention exhibits excellent thermal stability and mechanical properties, and has self-catalytic ability, and can be quickly remodeled. It provides a new solution for the polyurea dynamic covalent polymer network, achieving a good balance between mechanical strength and network exchange speed.

[0049] As another aspect of the technical solution of the present invention, it involves an aromatic guanidine amino acid remodelable polyguanidine urea material prepared by the aforementioned method, which has the functions of thermal stability, high strength, and self-catalytic rapid remodeling processing.

[0050] Furthermore, the remodelable polyguanidine urea material of the aromatic guanidine amino acid has a glass transition temperature of 110 to 150° C., an initial thermal degradation temperature of 230 to 275° C., a Young's modulus of 1020 to 1750 MPa, and a tensile strength of 40.1 to 131.7 MPa.

[0051] Furthermore, the remodelable polyguanidine urea material of the aromatic guanidine amino acid is hot-pressed at 100-140° C. for 5-60 min to achieve remodeling.

[0052] Unless otherwise defined, the meaning of all technical and scientific terms used herein is the same as that generally understood by those of ordinary skill in the art to which the present disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosed composition embodiments, suitable methods and materials are described below. Unless citing a specific paragraph, all publications, patent applications, patents and other references mentioned herein are incorporated herein by reference in their entirety. If a conflict occurs, this specification and the definitions included therein shall prevail. In addition, materials, methods and examples are illustrative only, and not restrictive.

[0053] The technical scheme of the present invention, its implementation process and principle, etc. will be further explained through specific embodiments as follows. It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. The described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. Unless otherwise specified, the reagents and raw materials used in the following examples are commercially available, and the test methods for which specific conditions are not specified are usually carried out under conventional conditions or according to the conditions recommended by the manufacturers. In addition, unless otherwise specified, the experimental methods, detection methods, and preparation methods disclosed in the present invention all adopt conventional techniques in the art. These technologies have been fully described in the existing literature.

[0054] The technical solution of the present invention is described in detail below through specific embodiments.

[0055] Example 1

[0056] The preparation method of the polyguanidine urea material provided in this embodiment specifically comprises the following steps:

[0057] Guanidine benzoic acid, 1,5-pentanedimethyl diisocyanate, hexaethylene diisocyanate trimer, water and dimethyl sulfoxide are mixed in a three-necked flask at a molar ratio of 1:0.5:1:1:50; the mixed system is placed in a 100°C oil bath for pre-reaction for 1 hour, during which flowing nitrogen is introduced; the pre-reaction product is placed in a 90°C vacuum oven for evacuation for 2 hours to remove the solvent; then, the reactant is poured into a polytetrafluoroethylene mold, first cured at 110°C for 1 hour on a hot plate, and then cured at 150°C for 1 hour; after natural cooling, a transparent light yellow film material is obtained, which is a polyguanidine urea material of aromatic guanidine amino acid.

[0058] The mechanical properties of the material in this example are shown in Figure 1 , Young's modulus is 1230MPa and tensile strength is 43.5MPa.

[0059] The glass transition temperature of this material is 117°C and the initial thermal degradation temperature is 245°C.

[0060] After the polymer network material prepared in this example is cut into pieces, it is hot-pressed at 120° C. for 30 min using a flat vulcanizer to obtain the following: Figure 2 Complete material shown.

[0061] Example 2

[0062] The preparation method of the polyguanidine urea material provided in this embodiment specifically comprises the following steps:

[0063] Guanidinobenzoic acid, 1,5-pentanedimethyl diisocyanate, L-lysine diisocyanate, water and dimethyl sulfoxide were mixed in a three-necked flask at a molar ratio of 1:2:0.5:1:70; the mixed system was placed in a 135°C oil bath for pre-reaction for 1 hour, during which flowing nitrogen was introduced; the pre-reaction product was placed in a 90°C vacuum oven for evacuation for 2 hours to remove the solvent; then, the reactants were poured into a polytetrafluoroethylene mold, first cured at 140°C on a hot plate, then cured at 150°C for 1 hour, and finally cured at 170°C for 1 hour; after natural cooling, a transparent light yellow film material was obtained.

[0064] The material has a glass transition temperature of 123°C, a Young's modulus of 1640 MPa, a tensile strength of 101.6 MPa, and an initial thermal degradation temperature of 275°C.

[0065] After the polymer network material prepared in this example is cut into pieces, it is hot-pressed at 140° C. for 50 minutes using a flat-plate vulcanizer to obtain a complete material again.

[0066] Example 3

[0067] The preparation method of the polyguanidine urea material provided in this embodiment specifically comprises the following steps:

[0068] 4-guanidine-2-methoxybenzoic acid, hexamethylene diisocyanate, water and N,N-dimethylformamide were mixed in a three-necked flask at a molar ratio of 1:2:1:90; the mixed system was placed in a 140°C oil bath for pre-reaction for 1.5 hours, during which flowing nitrogen was introduced; the pre-reaction product was placed in a 70°C vacuum oven for evacuation for 1 hour to remove the solvent; then, the reactants were poured into a polytetrafluoroethylene mold, first cured at 140°C on a hot plate for 1 hour, then cured at 155°C for 1 hour, and finally heated to 170°C for 30 minutes; after natural cooling, a transparent light yellow film material was obtained.

[0069] The material has a glass transition temperature of 135° C., a Young's modulus of 1520 MPa, a tensile strength of 78.9 MPa, and an initial thermal degradation temperature of 242° C. After the polymer network material prepared in this embodiment is cut into pieces, it is hot-pressed at 100° C. for 60 minutes using a flat plate vulcanizer to obtain a complete material.

[0070] Example 4

[0071] The preparation method of the polyguanidine urea material provided in this embodiment specifically comprises the following steps:

[0072] 4-(3-Ureaylguanidino)benzoic acid, hexamethylene diisocyanate, L-lysine diisocyanate, water and ethanol were mixed in a three-necked flask at a molar ratio of 1:1.5:1:1:100; the mixed system was placed in a 115°C oil bath for pre-reaction for 2 hours, during which flowing nitrogen was introduced; the pre-reaction product was placed in a 70°C vacuum oven for 0.5 hours to remove the solvent; then, the reactant was poured into a polytetrafluoroethylene mold, first cured at 120°C for 1 hour on a hot plate, and then cured at 150°C for 1 hour; after natural cooling, a transparent light yellow film material was obtained.

[0073] The material has a glass transition temperature of 135°C, a Young's modulus of 1457MPa, a tensile strength of 94.7MPa, and an initial thermal degradation temperature of 256°C.

[0074] After the polymer network material prepared in this example is cut into pieces, it is hot-pressed at 135° C. for 15 minutes using a flat-plate vulcanizer to obtain a complete material again.

[0075] Example 5

[0076] The preparation method of the polyguanidine urea material provided in this embodiment specifically comprises the following steps:

[0077] 4-guanidine-2-methoxybenzoic acid, hexamethylene diisocyanate, water, and N,N-dimethylformamide were mixed in a three-necked flask at a molar ratio of 1:1.2:1:90; the mixed system was placed in a 90°C oil bath for pre-reaction for 0.5 h, during which flowing nitrogen was introduced; the pre-reaction product was placed in a 70°C vacuum oven for evacuation for 1 h to remove the solvent; then, the reactants were poured into a polytetrafluoroethylene mold, first cured at 100°C on a hot plate for 1 h, then cured at 110°C for 1 h, and then heated to 170°C for 30 h; after natural cooling, a transparent light yellow film material was obtained.

[0078] The material has a glass transition temperature of 110° C., a Young's modulus of 1126 MPa, a tensile strength of 40.2 MPa, and an initial thermal degradation temperature of 231° C. After the polymer network material prepared in this embodiment is cut into pieces, it is hot-pressed at 140° C. for 5 minutes using a flat plate vulcanizer to obtain a complete material.

[0079] Example 6

[0080] The preparation method of the polyguanidine urea material provided in this embodiment specifically comprises the following steps:

[0081] Guanidinobenzoic acid, 1,5-pentanedimethyl diisocyanate, water and ethanol were mixed in a three-necked flask at a molar ratio of 1:1.5:1:100; the mixed system was placed in a 105℃ oil bath for pre-reaction for 2h, during which flowing nitrogen was introduced; the pre-reaction product was placed in a 70℃ vacuum oven for 0.5h to remove the solvent; then, the reactant was poured into a polytetrafluoroethylene mold, first cured at 120℃ for 1h on a hot plate, and then cured at 150℃ for 1h; after natural cooling, a transparent light yellow film material was obtained.

[0082] The material has a glass transition temperature of 112° C., a Young's modulus of 1057 MPa, a tensile strength of 43.9 MPa, and an initial thermal degradation temperature of 243° C. After the polymer network material prepared in this embodiment is cut into pieces, it is hot-pressed at 120° C. for 15 minutes using a flat plate vulcanizer to obtain a complete material.

[0083] Comparative Example 1

[0084] The difference between this comparative example and Example 1 is that guanidine benzoic acid is replaced with a commercial raw material aliphatic polyurea (Gaodun N-100) to obtain a polyurea material.

[0085] The prepared material has low mechanical strength, with a Young's modulus of 110 MPa and a tensile strength of 11.3 MPa.

[0086] Once the final material is cut into pieces, it cannot be reshaped.

[0087] Comparative Example 2

[0088] The difference between this comparative example and Example 1 is that guanidine benzoic acid is replaced by a commercial raw material polyaspartic acid polyester (Feiyang Junyan F420) to prepare a polyurethane material.

[0089] The Young's modulus of the obtained material was 336 MPa and the tensile strength was 23.5 MPa.

[0090] After the final material is cut into pieces, it can be reshaped after being hot-pressed at 160°C for 2 hours using a flat-plate vulcanizer, and the reshaping is relatively slow.

[0091] Comparative Example 3

[0092] Compared with Example 1, this comparative example has only a different molar ratio of raw materials, guanidinobenzoic acid, 1,5-pentanedimethyl diisocyanate, hexaethylene diisocyanate trimer, water, and dimethyl sulfoxide according to 1:0.5:0.5:1:50, and other conditions are the same. The Young's modulus of the material is 970MPa and the tensile strength is 32.4Mpa. After the polymer network material prepared in this embodiment is cut into pieces, a flat plate vulcanizer is used to hot press at 120°C for 10min to obtain a complete material. Compared with Example 1, the remodeling speed of the material is accelerated, but the mechanical properties are significantly reduced.

[0093] Comparative Example 4

[0094] Compared with Example 1, this comparative example only performs one curing during the curing process, the curing temperature is 150°C, the curing time is 2h, and no secondary curing is performed. The Young's modulus of the material is 230MPa, and the tensile strength is 10.3Mpa. After the polymer network material prepared in this example is cut into pieces, a complete material can be obtained by heating it at 120°C for 7min using a flat vulcanizer. Compared with Example 1, the material that has not undergone secondary curing has no uniform and complete cross-linked network formed, and although the remodeling speed is accelerated, the mechanical properties are significantly reduced.

[0095] Comparative Example 5

[0096] This comparative example is different from Example 1 only in the curing temperature. The primary curing during the curing process has a curing temperature of 150°C and a curing time of 1h. The secondary curing temperature is 170°C and the curing time is 1h. The Young's modulus of the material is 210MPa and the tensile strength is 9.5Mpa. After the polymer network material prepared in this example is cut into pieces, a complete material can be obtained by heating it at 120°C for 7min using a flat vulcanizer. Compared with Example 1, the material that has not undergone secondary curing has not formed a uniform and complete cross-linked network. Although the remodeling speed is accelerated, the mechanical properties are significantly reduced.

[0097] Through the above technical scheme, it can be known that the present invention uses aromatic guanidine amino acid monomers and multifunctional isocyanate compounds as raw materials to form guanidine urea bonds and amide bonds to obtain remodelable polyguanidine urea materials. Based on the aromatic structure and guanidine urea structure, the multi-level hydrogen bonds within the material and between molecules and the π-π stacking between molecules form non-covalent interactions, thereby enhancing the mechanical properties of the dynamic covalent polymer network.

[0098] The above are only preferred embodiments of the present invention, which do not limit the protection scope of the present invention. For those skilled in the art, the present invention may have various modifications and changes. Within the spirit and principle of the present invention, changes, modifications, replacements, integrations and parameter changes to these embodiments by conventional substitutions or by being able to achieve the same functions without departing from the principles and spirit of the present invention all fall within the protection scope of the present invention.

Claims

1. A method for preparing a remodelable polyguanidine urea material based on aromatic guanidine amino acids, characterized in that: Aromatic guanidine amino acid monomers, multifunctional isocyanate compounds and solvents are uniformly mixed to form a reaction system, and after pre-reaction, the solvent is removed and solidified to obtain a remodelable polyguanidine urea material; wherein the remodelable polyguanidine urea material has a dynamic covalent polymer network structure formed by the aromatic guanidine amino acid and the multifunctional isocyanate.

2. The preparation method according to claim 1, characterized in that: The aromatic guanidine amino acid monomer is a guanidine carboxylic acid compound containing an aromatic structure, a guanidine group and a carboxyl functional group; and / or the aromatic guanidine amino acid monomer is a combination of any one or more of guanidine benzoic acid, 4-guanidine-2-methoxybenzoic acid, and 4-(3-ureaguanidine)benzoic acid.

3. The preparation method according to claim 1, characterized in that: The multifunctional isocyanate compound includes any one of pentamethylene isocyanate, hexamethylene diisocyanate, L-lysine diisocyanate, 1,5-pentamethylene diisocyanate, and hexaethylene diisocyanate trimer, or a combination of two or more thereof.

4. The preparation method according to claim 1, characterized in that: The solvent is a mixture consisting of water and any one or a combination of ethanol, dimethyl sulfoxide and N,N-dimethylformamide.

5. The preparation method according to any one of claims 1 to 4, characterized in that: In the reaction system, the ratio of the sum of the moles of guanidine group, carboxyl group and water to the mole of isocyanate group is 1:(1-1.5), and the ratio of the moles of water to the organic solvent is 1:50-200.

6. The preparation method according to claim 5, characterized in that: The pre-reaction comprises reacting at 90-150° C. for 0.5-2 h.

7. The preparation method according to claim 5, characterized in that: The solvent removal comprises performing the step of performing the step under vacuum and 65 to 90° C. for 0.5 to 2 h; And / or, the curing is gradient temperature curing; And / or, the number of curing is 2N3 times; And / or, the curing condition is curing at 110-170° C. for 1-3 hours.

8. A remodelable polyguanidine urea material prepared by the preparation method according to any one of claims 1 to 6.

9. The remodelable polyguanidine urea material according to claim 8, characterized in that: The remodelable polyguanidine urea material can be remodeled by hot pressing at 115 to 155° C. for 5 to 60 minutes; And / or, the remodelable polyguanidine urea material has a glass transition temperature of 110 to 150° C., an initial thermal degradation temperature of 230 to 275° C., a Young's modulus of 1020 to 1750 MPa, and a tensile strength of 40.1 to 131.7 MPa.

10. Use of the remodelable polyguanidine urea material according to any one of claims 8 to 9 in the fields of waterproof materials, anti-corrosion pipelines, and national defense and military industries.

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