A bio-based aliphatic polyguanidine urea material, and a preparation method and application thereof

Abstract

The application discloses a kind of bio-based aliphatic polyguanidine urea material and its preparation method and application, it is related to polymer material technical field.The preparation method includes making the uniform mixing reaction system containing bio-based aliphatic guanidino amino acid monomer, multi-functionality isocyanate compound, solvent, first pre-reaction is carried out, after removing solvent, then solidification is carried out, and the remoldable polyguanidine urea material based on bio-based aliphatic guanidino amino acid is obtained.The technical scheme of the application avoids excessive consumption of petrochemical resources, and the preparation method is simple, a safer, catalyst-free green preparation system is used, without catalyst by the multi-level hydrogen bond and non-covalent bond in structure, reaction condition is mild, operability is strong, easy to realize industrial production, the material prepared has good thermal stability, excellent mechanical property, fast dynamic exchange speed, can be realized by simple hot-pressing method fast remolding reprocessing, and has excellent application prospect.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a bio-based aliphatic polyguanidinium urea material, its preparation method, and its application. Background Technology

[0002] Thermosetting polymers are widely used in various fields of life and production due to their excellent mechanical properties, dimensional stability, and chemical stability. However, while the cross-linked network within thermosetting polymers endows them with excellent properties, it also brings a series of problems such as difficulty in repairing defects, difficulty in waste disposal, and high recycling costs. Therefore, research on self-healing thermosetting polymers has emerged. By using dynamic covalent bonds as the cross-linking bonds within thermosetting polymers, these materials can exhibit stable, insoluble cross-linked polymers under certain conditions, possessing all the excellent properties of traditional thermosetting polymers. Under certain conditions, a dynamic exchange reaction occurs, causing the cross-linked network structure to rearrange, thus achieving self-healing of the thermosetting material. This opens up a promising path for the effective recycling and reprocessing of thermosetting polymers.

[0003] Aliphatic polyurea materials possess excellent weather resistance, good mechanical strength, and chemical stability, making them widely used in corrosion protection and waterproofing. However, the traditional preparation process of aliphatic polyurea materials often requires the catalytic action of a catalyst to promote the reaction between isocyanate and amine components, thereby completing the curing process. CN110790888A discloses a method for preparing self-healing polyurea elastomers. Through the reaction of multifunctional polyether amines and multifunctional isocyanates, catalyzed by catalysts such as dibutyltin dilaurate and triethylamine, a method for preparing high-tensile, tear-resistant self-healing polyurea was obtained. However, this method still suffers from a complex preparation process and a slow self-healing rate in the resulting polyurea material. Furthermore, this method requires the use of a catalyst, which carries the risks of catalyst precipitation, deactivation, and contamination.

[0004] On the other hand, with increasing emphasis on green chemistry, higher demands are being placed on the greenness of raw material sources, the simplicity of reaction processes, energy efficiency, and pollution-free operation. Using renewable bio-derived monomers as raw materials to replace petroleum-based materials in polymer preparation, employing safer, more convenient, and catalyst-free green preparation systems, helps reduce environmental impact. Furthermore, these bio-derived monomers can be used to prepare self-healing polyurea materials for repeated use, eliminating the need for recycling and extending the material's lifespan, thus providing technical support for sustainable resource development. Therefore, providing a high-strength, rapidly remodelable bio-based polyurea material is one of the important directions in the current development of polyurea materials.

[0005] Based on the above analysis, the present invention makes further improvements on the basis of the prior art. Using bio-based aliphatic guanidine amino acid monomers and polyfunctional isocyanate compounds as raw materials, a remodelable bio-based aliphatic polyguanidine urea material based on bio-based aliphatic guanidine amino acids is obtained to solve the problems existing in the prior art. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the present invention aims to provide a method for preparing bio-based aliphatic polyguanidinium urea materials, thereby overcoming the shortcomings of the prior art.

[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 bio-based aliphatic polyguanidinium urea material, wherein a monomer containing a bio-based aliphatic guanidinium amino acid is directly crosslinked with a multifunctional isocyanate compound without a catalyst to obtain a remodelable bio-based aliphatic polyguanidinium urea material based on aliphatic guanidinium amino acids.

[0009] In some specific embodiments, the preparation method of the bio-based aliphatic polyguanidinium urea material includes the following steps:

[0010] A reaction system is formed by uniformly mixing a bio-based aliphatic guanidine amino acid monomer, a polyfunctional isocyanate compound, and a solvent.

[0011] The pre-reaction was carried out under a nitrogen atmosphere and heated to 65–115 °C.

[0012] After removing the solvent, a curing reaction is carried out to obtain the bio-based aliphatic polyguanidinium urea material.

[0013] Preferably, the bio-based aliphatic guanidine amino acid monomer is an aliphatic guanidine carboxylic acid compound containing both guanidine and carboxyl functional groups. The bio-based aliphatic guanidine amino acid monomer reacts with a multifunctional isocyanate compound to form guanidineurea and amide structures. These structures contain multi-level hydrogen bonds and non-covalent bonds, exhibiting autocatalytic activity. Therefore, no additional catalyst is needed during the reaction, allowing for rapid subsequent reactions. Simultaneously, the rapid exchange of the dynamic covalent polymer network enables rapid reshaping of the polyguanidineurea material. Furthermore, intramolecular / intermolecular hydrogen bonding and intermolecular π-π stacking form non-covalent interactions, which improve the mechanical properties of the polymer network.

[0014] More preferably, the bio-based aliphatic guanidine amino acid monomers include, but are not limited to, any one or a combination of two or more of arginine, ornithine, 2-guanidinosuccinic acid, 2-guanidinoethyl mercaptosuccinic acid, guanidinoacetic acid, guanidinopropionic acid, and 6-guanidinohexanoic acid.

[0015] Preferably, the polyfunctional isocyanate compound includes, but is not limited to, any one or a combination of two or more of pentamethylene isocyanate, hexamethylene diisocyanate, L-lysine diisocyanate, 1,5-pentanedimethyl diisocyanate, and hexaethylene diisocyanate trimer.

[0016] Preferably, the solvent comprises water, or a mixture of water and any one or more of ethanol, dimethyl sulfoxide, and N,N-dimethylformamide.

[0017] Preferably, in the reaction system, the ratio of the sum of the moles of guanidine groups, carboxyl groups, and water to the moles of isocyanate groups is 1:(1 to 1.5), and the ratio of the moles of water to organic solvents is 1:50 to 200.

[0018] Preferably, the pre-reaction includes reacting at 65–115°C for 0.5–2 hours.

[0019] Preferably, the solvent removal process includes performing the process under vacuum and at 65–90°C for 0.5–2 hours.

[0020] Preferably, the curing is a gradient temperature curing process.

[0021] Preferably, the curing process is performed 2 to 3 times.

[0022] Preferably, the curing conditions are curing at 110–160°C for 1–3 hours.

[0023] As one of the objectives of the invention, the present invention also provides a bio-based aliphatic polyguanidinium urea material, which is prepared using the aforementioned preparation method.

[0024] Preferably, the bio-based aliphatic polyguanidinium urea material can be reshaped by hot pressing at 100–140°C for 5–60 minutes.

[0025] Preferably, the bio-based aliphatic polyguanidinium urea material has a glass transition temperature of 90–120°C, an initial thermal degradation temperature of 200–270°C, a Young's modulus of 980–1750 MPa, and a tensile strength of 40.1–97.6 MPa.

[0026] Technical effects of the present invention:

[0027] 1. This invention prepares high-performance, remodelable polyguanidinium urea materials by combining bio-based aliphatic guanidinoamino acids with polyfunctional isocyanates. On one hand, the multi-level hydrogen bonds within the material and between molecules, along with the π-π stacking between molecules, form non-covalent interactions, enhancing the mechanical properties of the dynamic covalent polymer network. On the other hand, the guanidinium structure and the amide structure form hydrogen bonds between guanidinourea molecules, facilitating the rapid exchange of the dynamic covalent polymer network, thus enabling the material to be remodeled in a short time. The aromatic guanidinoamino acid remodelable polyguanidinium urea material prepared in this way not only possesses excellent thermodynamic stability and mechanical properties but also enables rapid autocatalytic remodeling.

[0028] 2. The preparation method of bio-based aliphatic polyguanidinium urea material provided by the present invention does not require the addition of a catalyst and selects a green bio-based aliphatic guanidinocarboxylic acid compound containing both guanidinium and carboxyl functional groups as a raw material, avoiding the use of petrochemical-based raw materials. At the same time, it does not require a catalyst and adopts a more convenient and efficient synthesis method. The prepared bio-based polyguanidinium urea material exhibits excellent thermal stability and mechanical properties, and also has self-catalytic ability, can be quickly remodeled, and is especially environmentally friendly, safe and able to quickly achieve self-repair function, thus expanding the application range of polyurea materials.

[0029] 3. This invention uses bio-based raw materials as polymer monomers, and the resulting polyguanidinium urea material not only has the function of rapid remodeling, but also does not require the addition of catalysts in the preparation process. In addition to being green and environmentally friendly, it can also extend the service life of the material through rapid remodeling, thereby providing technical support for the true realization of sustainable resource development.

[0030] 4. The preparation method of aliphatic polyguanidinium urea material provided by the technical solution of the present invention has the advantages of simple method and no need for catalyst, and is highly operable and easy to implement. It is a brand-new method to achieve a balance between the mechanical strength and network exchange rate of dynamic covalent polymer network, and is suitable for large-scale industrial promotion and production. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a sample photograph of the remodelable polyguanidinium material of bio-based aliphatic guanidine amino acids obtained in Example 1 of the present invention.

[0033] Figure 2The infrared spectrum of the remodelable polyguanidinium material of bio-based aliphatic guanidine amino acids obtained in Example 1 of this invention is shown. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0035] All patent and non-patent literature publications cited in this invention are incorporated herein by reference.

[0036] The terms “comprising,” “including,” “containing,” “covering,” “having,” “with,” or any other variations thereof, as used in this invention, are intended to cover non-exclusive inclusion. For example, a process, method, article of manufacture, or apparatus that includes a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to the process, method, article of manufacture, or apparatus. Furthermore, unless expressly stated otherwise, “or” means inclusive “or” rather than exclusive “or.” For example, condition A or B satisfies any of the following: A is real (or exists) and B is fictitious (or does not exist); A is fictitious (or does not exist) and B is real (or exists); and both A and B are real (or exist). The phrase “one or more” is intended to cover non-exclusive inclusion. For example, one or more 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.

[0037] Additionally, the terms "an" or "a" are used to describe the elements and components described herein. This is done solely for convenience and to provide a general meaning regarding 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 includes the plural unless explicitly stated otherwise.

[0038] This invention prepares remodelable polyguanidinium urea materials using bio-based aliphatic guanidine amino acids and multifunctional isocyanates. These materials possess excellent thermal and mechanical properties, enable rapid autocatalytic remodeling, and are simple to prepare without the need for catalysts. They are highly operable and easy to implement, representing a novel method for achieving a balance between the mechanical strength and network exchange rate of dynamic covalent polymer networks.

[0039] Specifically, as one aspect of the technical solution of the present invention, the remodelable polyguanidinium material based on bio-based aliphatic guanidine amino acids and its preparation method are characterized by comprising: firstly, pre-reacting a uniformly mixed reaction system containing aliphatic guanidine amino acid monomers, multifunctional isocyanate compounds, and solvents, then removing the solvent and then curing it to obtain the remodelable polyguanidinium material based on bio-based aliphatic guanidine amino acids.

[0040] The reaction mechanism of this invention is as follows: The method for preparing remodelable polyguanidinium urea materials based on bio-based aliphatic guanidino acid proposed in this invention involves uniformly mixing the reactants with a solvent, followed by the reaction of aliphatic guanidino acid containing guanidinium and carboxyl functional groups with a polyfunctional isocyanate to form guanidinourea bonds and amide bonds, resulting in remodelable polyguanidinium urea materials. Non-covalent interactions are formed through multi-level hydrogen bonds within the guanidinourea structure and between molecules, as well as π-π stacking between molecules, thereby enhancing the mechanical properties of the dynamic covalent polymer network. The hydrogen bonds formed between the guanidinourea structure and the amide structure in the guanidinourea material molecules facilitate rapid exchange within the dynamic covalent polymer network, enabling the material to be remodeled in a short time. In selecting the reactants, this invention adheres to the principles of green chemistry, using bio-based aliphatic guanidino acid as the raw material, which not only reduces dependence on petroleum-based chemicals but also lowers the environmental impact. The method for preparing this material is not only simple and easy to implement but also requires no catalyst, greatly simplifying the production process. The synthesized bio-based aliphatic guanidine amino acid-remodelable polyguanidinium urea material exhibits excellent thermal stability and mechanical properties, while also possessing self-catalytic capabilities and rapid remodeling. This provides a novel solution for dynamic covalent polymer networks of polyurea, achieving a good balance between mechanical strength and network renewal speed.

[0041] In some preferred embodiments, the preparation method specifically includes the following steps: a homogeneous mixing reaction system of aliphatic guanidine amino acid monomer, polyfunctional isocyanate compound, and solvent, firstly undergoing a pre-reaction, then removing the solvent, and then curing by gradient temperature increase to prepare a remodelable polyguanidinium material based on aliphatic guanidine amino acids.

[0042] In some embodiments, the aliphatic guanidine amino acid monomers include, but are not limited to, any one or a combination of two or more of guanidine carboxylic acid compounds containing both guanidine and carboxyl functional groups, such as arginine, ornithine, 2-guanidine succinic acid, 2-guanidine ethyl mercaptosuccinic acid, guanidine acetic acid, guanidine propionic acid, and 6-guanidine hexanoic acid.

[0043] In some preferred embodiments, the polyfunctional isocyanate compound includes, but is not limited to, any one or a combination of two or more of pentamethylene isocyanate, hexamethylene diisocyanate, phenyl diisocyanate, L-lysine diisocyanate, 1,5-pentanedimethyl diisocyanate, hexaethylene diisocyanate trimer and its derivatives.

[0044] In some preferred embodiments, the solvent includes water, and also includes any one or a combination of two or more solvents such as ethanol, dimethyl sulfoxide, and N,N-dimethylformamide.

[0045] In some preferred embodiments, the preparation method includes: uniformly mixing guanidine- and carboxyl-containing bio-based amino acids, polyfunctional isocyanate compounds, and solvents to form the uniformly mixed reaction system.

[0046] Furthermore, in the homogeneous mixed reaction system, the molar ratio of the sum of guanidine groups, carboxyl groups, and water to cyanate groups is 1 to (1 to 1.5), and the molar ratio of water to organic solvent is 1:50 to 200.

[0047] In some preferred embodiments, the preparation method includes: subjecting the homogeneous mixed reaction system to a pre-reaction at 65–115°C for 0.5–2 hours.

[0048] In some preferred embodiments, the homogeneous mixed reaction system is placed in a vacuum oven at 65–90°C for 0.5–2 hours to remove the solvent.

[0049] Furthermore, the curing process involves curing at 95–150°C for 1–3 hours once or multiple times.

[0050] Furthermore, the remodelable polyguanidinium material of the bio-based aliphatic guanidine amino acid is prepared by curing guanidine- and carboxyl-containing bio-based amino acids and polyfunctional isocyanate compounds without a catalyst.

[0051] In summary, the bio-based aliphatic guanidine amino acid-remodelable polyguanidinium urea material prepared by this invention exhibits excellent thermal stability and mechanical properties. Furthermore, through multi-level hydrogen bonding and non-covalent interactions in its structure, it possesses autocatalytic capabilities, enabling rapid remodeling. This provides a novel solution for dynamic covalent polymer networks in polyurea, achieving a good balance between mechanical strength and network exchange rate.

[0052] As another aspect of the technical solution of the present invention, it involves a bio-based aliphatic guanidine amino acid remodelable polyguanidium urea material prepared by the aforementioned method, which has the functions of thermal stability, high strength and self-catalytic rapid remodeling processing.

[0053] Furthermore, the glass transition temperature of the bio-based aliphatic guanidine amino acid remodelable polyguanidium urea material is 90–120°C, the initial thermal degradation temperature is 200–270°C, the Young's modulus is 980–1750 MPa, and the tensile strength is 40.1–97.6 MPa.

[0054] Furthermore, the remodelable polyguanidinium material based on bio-based aliphatic guanidine amino acids is remodeled by hot pressing at 100–140°C for 5–60 min.

[0055] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. While similar or equivalent methods and materials described herein may be used in the practice or testing of embodiments of the disclosed compositions, suitable methods and materials are those described below. All publications, patent applications, patents, and other references mentioned herein are incorporated herein by reference in their entirety, unless specific paragraphs are quoted. In case of any conflict, this specification and its included definitions shall prevail. Furthermore, materials, methods, and examples are illustrative only and not limiting.

[0056] The technical solution, implementation process, and principle of the present invention will be further explained and illustrated below through specific embodiments. It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. The described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise stated, the reagents and raw materials used in the following embodiments are commercially available, and the test methods without specific conditions are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers. Furthermore, unless otherwise stated, the experimental methods, detection methods, and preparation methods disclosed in the present invention all employ conventional techniques in this technical field. These techniques have been well described in existing literature.

[0057] The technical solution of the present invention will be described in detail below through specific embodiments.

[0058] Example 1

[0059] The preparation method of the bio-based aliphatic polyguanidinium urea material provided in this embodiment specifically includes the following steps:

[0060] Guanidinoacetic acid, L-lysine diisocyanate, hexaethylene diisocyanate trimer, and water:dimethyl sulfoxide were mixed in a three-necked flask at a molar ratio of 1:0.5:1:1:100. The mixture was pre-reacted in a 90°C oil bath for 1 hour under flowing nitrogen. The pre-reaction product was then placed in a 90°C vacuum oven for 1 hour to remove the solvent. Subsequently, the reactants were poured into a polytetrafluoroethylene mold and first cured at 110°C for 1 hour, followed by a second curing at 150°C for 1 hour. After natural cooling, the product was obtained as shown in the figure. Figure 1 The transparent, light yellow film material is a polyguanidine urea material based on bio-based aliphatic guanidine amino acids.

[0061] like Figure 2 As shown, the infrared spectrum of the polyguanidinium urea material prepared in this embodiment is 3315 cm⁻¹. -1 The characteristic peak at this point is the -CONH- absorption peak, at 1637 cm⁻¹. -1 The characteristic peaks are contributed by -N-CO-N-, indicating the formation of a polyurea structure. Furthermore, the C=O characteristic peak changes from the free peak at 1700-1750 cm⁻¹. -1 The migration point is 1685cm as shown in the diagram. -1 This change may be caused by the formation of intermolecular and intramolecular hydrogen bonds in the C=O group of the acetyl group after the reaction, which also proves the success of the material synthesis.

[0062] The polyguanidine urea material prepared in this embodiment has a glass transition temperature of 103℃, a Young's modulus of 1030MPa, a tensile strength of 39.7MPa, and an initial thermal degradation temperature of 225℃.

[0063] After cutting the polymer network material prepared in this embodiment into small pieces, it is hot-pressed at 120°C for 20 minutes using a flat vulcanizing apparatus to obtain a complete material again. (See attached document.) Figure 1 This refers to the reshaped polyguanidine urea material, which is intact after reshaping.

[0064] Example 2

[0065] The preparation method of the bio-based aliphatic polyguanidinium urea material provided in this embodiment specifically includes the following steps:

[0066] L-arginine, phenyl dimethyl diisocyanate, L-lysine diisocyanate, and methyl sulfoxide were mixed in a three-necked flask at a molar ratio of 1:2:0.5:1:100. The mixture was pre-reacted in an oil bath at 80°C for 1 hour under flowing nitrogen. The pre-reaction product was then placed in a vacuum oven at 90°C to remove the solvent. Subsequently, the reactants were poured into a polytetrafluoroethylene mold and first cured at 100°C for 1 hour, then cured again at 110°C for 1 hour, and finally cured at 120°C for 1 hour. After natural cooling, a transparent light yellow film material was obtained.

[0067] The polyguanidinium urea material prepared in this embodiment has a glass transition temperature of 108°C, a Young's modulus of 995 MPa, a tensile strength of 41.6 MPa, and an initial thermal degradation temperature of 212°C.

[0068] After the polymer network material prepared in this embodiment is cut into pieces, it can be hot-pressed at 140°C for 10 minutes using a flat vulcanizing apparatus to obtain a complete material again.

[0069] Example 3

[0070] The preparation method of the bio-based aliphatic polyguanidinium urea material provided in this embodiment specifically includes the following steps:

[0071] Guanidinoacetic acid, hexamethylene diisocyanate, water, and N,N-dimethylformamide were mixed in a three-necked flask at a molar ratio of 1:1:1:70. The mixture was pre-reacted in a 95°C oil bath for 1.5 h under flowing nitrogen. The pre-reaction product was then placed in a 70°C vacuum oven and evacuated for 2 h to remove the solvent. Subsequently, the reactants were poured into a polytetrafluoroethylene mold and first cured at 100°C on a hot plate, then cured at 110°C for 1 h, and finally cured at 120°C for 1 h. After natural cooling, a transparent light yellow film material was obtained.

[0072] The polyguanidinium urea material prepared in this embodiment has a glass transition temperature of 117°C, a Young's modulus of 1520 MPa, a tensile strength of 78.9 MPa, and an initial thermal degradation temperature of 242°C.

[0073] After the polymer network material prepared in this embodiment is cut into pieces, it can be hot-pressed at 100°C for 60 minutes using a flat vulcanizing apparatus to obtain a complete material again.

[0074] Example 4

[0075] The preparation method of the bio-based aliphatic polyguanidinium urea material provided in this embodiment specifically includes the following steps:

[0076] Guanidinoacetic acid, hexamethylene diisocyanate, water, and N,N-dimethylformamide were mixed in a three-necked flask at a molar ratio of 1:1:1:70. The mixture was pre-reacted in a 95°C oil bath for 1.5 h under flowing nitrogen. The pre-reaction product was then placed in a 70°C vacuum oven and evacuated for 2 h to remove the solvent. Subsequently, the reactants were poured into a polytetrafluoroethylene mold and first cured at 100°C on a hot plate, then cured at 110°C for 1 h, and finally cured at 120°C for 1 h. After natural cooling, a transparent light yellow film material was obtained.

[0077] The polyguanidine urea material prepared in this embodiment has a glass transition temperature of 114℃, a Young's modulus of 1470MPa, a tensile strength of 63.9MPa, and an initial thermal degradation temperature of 242℃.

[0078] After the polymer network material prepared in this embodiment is cut into pieces, it is hot-pressed at 1470°C for 5 minutes using a flat vulcanizing apparatus to obtain a complete material again.

[0079] Example 5

[0080] The preparation method of the bio-based aliphatic polyguanidinium urea material provided in this embodiment specifically includes the following steps:

[0081] 2-Guidinosuccinic acid, hexamethylene diisocyanate, triphenylmethane triisocyanate, water, and ethanol were mixed in a three-necked flask at a molar ratio of 1:1.5:1:1:100. The mixture was pre-reacted in an oil bath at 115°C for 2 hours under flowing nitrogen. The pre-reaction product was then placed in a vacuum oven at 70°C for 0.5 hours to remove the solvent. Subsequently, the reactants were poured into a polytetrafluoroethylene mold and first cured at 120°C for 1 hour, followed by curing at 150°C for 1 hour. After natural cooling, a transparent light yellow film material was obtained.

[0082] The polyguanidine urea material prepared in this embodiment has a glass transition temperature of 105℃, a Young's modulus of 1732MPa, a tensile strength of 87.2MPa, and an initial thermal degradation temperature of 265℃.

[0083] After the polymer network material prepared in this embodiment is cut into pieces, it can be hot-pressed at 135°C for 15 minutes using a flat vulcanizing apparatus to obtain a complete material again.

[0084] Example 6

[0085] The preparation method of the bio-based aliphatic polyguanidinium urea material provided in this embodiment specifically includes the following steps:

[0086] 6-Guidinohexanoic 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 mixture was pre-reacted in an oil bath at 115°C for 2 hours under flowing nitrogen. The pre-reaction product was then placed in a vacuum oven at 70°C for 0.5 hours to remove the solvent. Subsequently, the reactants were poured into a polytetrafluoroethylene mold and first cured at 120°C for 1 hour, then cured at 150°C for 1 hour. After natural cooling, a transparent light yellow film material was obtained.

[0087] The polyguanidinium urea material prepared in this embodiment has a glass transition temperature of 108°C, a Young's modulus of 1572 MPa, a tensile strength of 52.7 MPa, and an initial thermal degradation temperature of 265°C.

[0088] After the polymer network material prepared in this embodiment is cut into pieces, it can be hot-pressed at 120°C for 30 minutes using a flat vulcanizing apparatus to obtain a complete material again.

[0089] Comparative Example 1

[0090] The difference between this comparative example and Example 1 is that guanidinoacetic acid was replaced with commercially available aliphatic polyurea (High Shield N-100), while the other steps were the same to obtain the polyurea material.

[0091] The material prepared in this comparative example has low mechanical strength, with a Young's modulus of 110 MPa and a tensile strength of 11.3 MPa. The final material cannot be reshaped after being cut into pieces.

[0092] Comparative Example 2

[0093] The difference between this comparative example and Example 1 is that guanidinoacetic acid was replaced with commercial raw material polyaspartic acid polyester (Feiyang Junyan F420) to prepare polyurea material.

[0094] The obtained polyurea material has a Young's modulus of 336 MPa and a tensile strength of 23.5 MPa.

[0095] After the final material is cut into pieces, it is then hot-pressed at 160°C for 2 hours using a flat vulcanizing machine before it can be reshaped, which is a slow process.

[0096] Comparative Example 3

[0097] Compared to Example 1, this comparative example differs only in the molar ratio of the raw materials: guanidinoacetic acid, L-lysine diisocyanate, hexaethylene diisocyanate trimer, and water:dimethyl sulfoxide are in a ratio of 1:0.5:0.5:1:100. All other conditions remain the same. The Young's modulus of the material is 784 MPa, and the tensile strength is 26.4 MPa. The polymer network material prepared in this example was cut into pieces and then hot-pressed at 120°C for 10 minutes using a flat vulcanizing apparatus to obtain a complete material again. Compared to Example 1, the polyguanidinium urea material prepared in this comparative example exhibits faster reshaping speed, but its mechanical properties are significantly reduced.

[0098] Comparative Example 4

[0099] Compared with Example 1, this comparative example only underwent one curing process and did not undergo a second curing, so the material could not be formed.

[0100] In summary, this invention uses bio-based aliphatic guanidine amino acids and polyfunctional isocyanates as raw materials to react and form guanidineurea and amide structures, and hydrogen bonds are formed between molecules to promote the rapid exchange of dynamic covalent polymer networks, thereby enabling polyguanidineurea materials to be reshaped in a short time. At the same time, the multi-level hydrogen bonds and π-π stacking between molecules within the material form non-covalent interactions, which can also increase the mechanical properties of the polymer network structure.

[0101] The above are merely preferred embodiments of the present invention and do not limit the scope of protection of the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any changes, modifications, substitutions, integrations, and parameter alterations to these embodiments within the spirit and principles of the present invention, achieved through conventional substitutions or by achieving the same function without departing from the principles and spirit of the present invention, fall within the scope of protection of the present invention.

Claims

1. A method for preparing a bio-based aliphatic polyguanidinium urea material, characterized in that, A remodelable bio-based aliphatic polyguanidinium urea material is obtained by directly crosslinking a bio-based aliphatic guanidinium amino acid monomer with a polyfunctional isocyanate compound without a catalyst. The specific steps include: A reaction system is formed by uniformly mixing a bio-based aliphatic guanidine amino acid monomer, a polyfunctional isocyanate compound, and a solvent. The pre-reaction is carried out under a flowing nitrogen atmosphere; After removing the solvent, a curing reaction is carried out to obtain the aliphatic polyguanidinium urea material; The bio-based aliphatic guanidine amino acid monomers include any one or more combinations of arginine, ornithine, 2-guanidinosuccinic acid, 2-guanidinoethyl mercaptosuccinic acid, guanidinoacetic acid, guanidinopropionic acid, and 6-guanidinohexanoic acid. And, the multifunctional isocyanate compound includes any one or a combination of two or more of pentamethylene isocyanate, hexamethylene diisocyanate, L-lysine diisocyanate, 1,5-pentanedimethyl diisocyanate, and hexaethylene diisocyanate trimer. In the reaction system, the ratio of the sum of the moles of guanidine groups, carboxyl groups and water to the moles of isocyanate groups is 1:(1~1.5), and the moles of water to solvent is 1:50~200. And, the curing is gradient temperature curing; The curing process is repeated 2 to 3 times. The curing conditions are 95~150℃ for 1~3 h.

2. The method for preparing the bio-based aliphatic polyguanidinium urea material according to claim 1, characterized in that, The solvent includes water, or a mixture of water and any one or more of ethanol, dimethyl sulfoxide, and N,N-dimethylformamide.

3. The method for preparing the bio-based aliphatic polyguanidinium urea material according to any one of claims 1-2, characterized in that, The pre-reaction involves reacting under a flowing nitrogen atmosphere at 65–115°C for 0.5–2 h.

4. The method for preparing the bio-based aliphatic polyguanidinium urea material according to any one of claims 1-2, characterized in that, The solvent removal process includes 0.5-2 h under vacuum and at 65-90 °C.

5. A bio-based aliphatic polyguanidinium urea material, prepared by the preparation method according to any one of claims 1-4.

6. The bio-based aliphatic polyguanidinium urea material according to claim 5, characterized in that, The bio-based aliphatic polyguanidinium urea material can be reshaped by hot pressing at 100~140 ℃ for 5~60 min; And / or, the glass transition temperature of the bio-based aliphatic polyguanidium urea material is 90~120℃, the initial thermal degradation temperature is 200~270℃, the Young's modulus is 980~1750 MPa, and the tensile strength is 40.1~97.6 MPa.

7. The application of the bio-based aliphatic polyguanidium urea material as described in any one of claims 5-6 in the field of waterproof and / or anti-corrosion materials.

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