Bio-based aliphatic polyguanidine urea material as well as preparation method and application thereof

Abstract

The invention discloses a bio-based aliphatic polyguanidine urea material 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 a bio-based aliphatic 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 remoldable polyguanidino urea material based on the bio-based aliphatic guanidino amino acid. According to the technical scheme, excessive consumption of petrochemical resources is avoided, the preparation method is simple, a safer and catalyst-free green preparation system is adopted, a catalyst is not needed under the action of multistage hydrogen bonds and non-covalent bonds in the structure, reaction conditions are mild, operability is high, industrial production is easy to achieve, and the method is suitable for industrial production. And the prepared material is good in thermal stability, excellent in mechanical property and high in dynamic exchange speed, can realize rapid remodeling and reprocessing through a simple hot-pressing method, and has a great application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a bio-based aliphatic polyguanidine urea material and a preparation method and application thereof. Background Art

[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 inside thermosetting polymers gives them excellent properties, it also brings a series of problems such as difficulty in repairing defects, difficulty in waste disposal, and high recycling costs. Therefore, the research on self-healing thermosetting polymers came into being. Using dynamic covalent bonds as cross-linking bonds inside thermosetting polymers can make this type of material behave as a stable insoluble cross-linked polymer under certain conditions, and have various excellent properties of traditional thermosetting polymers. Under certain conditions, dynamic exchange reactions will occur to rearrange the cross-linked network structure to achieve self-healing of thermosetting materials, opening up a promising path for the effective recycling and reprocessing of thermosetting polymers.

[0003] Aliphatic polyurea materials have excellent weather resistance, good mechanical strength and chemical stability, and are widely used in the fields of corrosion protection and waterproofing. However, in the preparation process of traditional aliphatic polyurea materials, the catalytic action of a catalyst is often required to promote the reaction between isocyanate and amine components to complete the curing process. CN110790888A discloses a method for preparing a self-repairable polyurea elastomer, through the reaction of multifunctional polyetheramine and multifunctional isocyanate, under the catalysis of catalysts such as dibutyltin dilaurate and triethylamine, a high tensile and tear-resistant self-repairing polyurea preparation method is prepared. However, this method still has the problem of complex preparation process, and the self-repairing speed of the obtained polyurea material is slow. In addition, this method requires the use of a catalyst, which has the risk of catalyst precipitation, deactivation, and pollution.

[0004] On the other hand, as people pay more attention to green chemistry, higher requirements are put forward for the greenness of raw material sources, simplicity of reaction processes, energy saving and pollution-free. Using renewable biological monomers as raw materials to replace petroleum-based materials to prepare polymers, and adopting a safer, more convenient, and catalyst-free green preparation system will help reduce the impact on the environment. At the same time, it can be used as a raw material to prepare self-repairing polyurea materials for repeated use, without the need for recycling and reuse, extending the service life of the material, thereby providing technical support for the sustainable development of resources. Therefore, providing a high-strength, fast-remodeling bio-based polyurea material is one of the important directions for the development of polyurea materials.

[0005] Based on the above analysis, the present invention has made further improvements on the basis of the prior art, using bio-based aliphatic guanidine amino acid monomers and multifunctional isocyanate compounds as raw materials to obtain a remodelable bio-based aliphatic polyguanidine urea material based on bio-based aliphatic guanidine amino acid to solve the problems existing in the prior art. Summary of the invention

[0006] In order to overcome the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a method for preparing a bio-based aliphatic polyguanidine urea material, thereby overcoming the deficiencies in 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 polyguanidine urea material, wherein a bio-based aliphatic guanidine amino acid monomer is directly cross-linked with a multifunctional isocyanate compound without a catalyst to obtain a remodelable bio-based aliphatic polyguanidine urea material based on a bio-based aliphatic guanidine amino acid.

[0009] In some specific embodiments, the method for preparing the bio-based aliphatic polyguanidine urea material comprises the following specific steps:

[0010] The bio-based aliphatic guanidine amino acid monomer, the multifunctional isocyanate compound and the solvent are uniformly mixed to form a reaction system;

[0011] Under a nitrogen atmosphere, pre-react by heating to 65-115°C;

[0012] After removing the solvent, a curing reaction is carried out to obtain the bio-based aliphatic polyguanidine 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 and the multifunctional isocyanate compound generate a guanidine urea structure and an amide structure, which contain multi-level hydrogen bonds and non-covalent bonds and have a self-catalytic effect. Therefore, no catalyst needs to be added during the reaction process, and subsequent reactions can be carried out quickly; at the same time, the rapid exchange of the dynamic covalent polymer network can achieve rapid remodeling of the polyguanidine urea material; moreover, the intramolecular / intermolecular hydrogen bonding and the intermolecular π-π stacking form non-covalent interactions, which can improve the mechanical properties of the polymer network.

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

[0015] 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.

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

[0017] 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.

[0018] Preferably, the pre-reaction comprises reacting at 65-115° C. for 0.5-2 h.

[0019] Preferably, the removing of the solvent comprises performing the step under vacuum at 65 to 90° C. for 0.5 to 2 h.

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

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

[0022] Preferably, the curing condition is 110-160° C. for 1-3 hours.

[0023] As one of the purposes of the invention, the present invention also provides a bio-based aliphatic polyguanidine urea material, which is prepared by the above-mentioned preparation method.

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

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

[0026] The technical effects of the technical solution of the present invention are as follows:

[0027] 1. The present invention prepares a high-performance, remodelable polyguanidine urea material by using bio-based aliphatic guanidine amino acids and multifunctional isocyanates. On the one hand, the multi-level hydrogen bonds within the material and between molecules and the π-π stacking between molecules form non-covalent interactions, which not only enhance the mechanical properties of 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 achieve self-catalytic rapid remodeling processing.

[0028] 2. The preparation method of the bio-based aliphatic polyguanidine urea material provided by the present invention does not require the addition of a catalyst, and uses a green bio-based aliphatic guanidine carboxylic acid compound containing both guanidine and carboxyl functional groups as a raw material, avoiding the use of petrochemical-based raw materials. At the same time, no catalyst is required, and a more convenient and effective synthesis method is adopted. The prepared bio-based polyguanidine urea material exhibits excellent thermal stability and mechanical properties, and has self-catalytic ability, can be quickly reshaped, and is particularly environmentally friendly, safe, and can quickly achieve self-repair functions, expanding the scope of use of polyurea materials.

[0029] 3. The present invention uses bio-based raw materials as polymerization monomers, and the provided polyguanidine urea material not only has the function of rapid remodeling, but also does not require the addition of catalysts during the preparation process. It has the advantages of being green and environmentally friendly, and can also extend the service life of the material through rapid remodeling, thereby providing technical support for truly realizing the sustainable development of resources.

[0030] 4. The method for preparing aliphatic polyguanidine urea materials provided by the technical solution of the present invention has the advantages of being simple and not requiring 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

[0031] 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.

[0032] Figure 1 This is a sample photo of the remodelable polyguanidine urea material of the bio-based aliphatic guanidine amino acid obtained in Example 1 of the present invention.

[0033] Figure 2This is an infrared spectrum of the remodelable polyguanidine urea material of the bio-based aliphatic guanidine amino acid obtained in Example 1 of the present invention. DETAILED DESCRIPTION

[0034] 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.

[0035] The disclosures of all patent and non-patent literature cited herein are incorporated herein by reference in their entirety.

[0036] 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.

[0037] 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.

[0038] The present invention prepares a remodelable polyguanidine urea material through bio-based aliphatic guanidine amino acid and multifunctional isocyanate, has excellent thermal and mechanical properties, can realize self-catalytic rapid remodeling processing, has a simple preparation method, does not require the use of a catalyst, 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.

[0039] Specifically, as one aspect of the technical solution of the present invention, a remodelable polyguanidine urea material based on bio-based aliphatic guanidine amino acid and a preparation method thereof are characterized in that the method comprises: firstly pre-reacting a uniformly mixed reaction system containing an aliphatic guanidine amino acid monomer, a multifunctional isocyanate compound, and a solvent, and then curing the system after removing the solvent to obtain a remodelable polyguanidine urea material based on bio-based aliphatic guanidine amino acid.

[0040] The reaction mechanism of the present invention is: the preparation method of the remodelable polyguanidine urea material based on bio-based aliphatic guanidine amino acid proposed by the present invention, after the reaction raw materials and the solvent are evenly mixed, the aliphatic guanidine amino acid containing guanidine and carboxyl functional groups and the multifunctional isocyanate react to form guanidine urea bonds and amide bonds to obtain the remodelable polyguanidine urea material. The multi-level hydrogen bonds within the guanidine urea structure and between molecules and the π-π stacking between molecules form non-covalent interactions, thereby achieving the enhancement of the mechanical properties of the dynamic covalent polymer network. 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. When selecting the reaction monomer, the present invention adheres to the principle of green chemistry and uses bio-based aliphatic guanidine amino acids as raw materials, which not only reduces the dependence on petroleum-based chemicals, but also reduces the environmental impact. 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 bio-based aliphatic guanidine amino acid remodelable polyguanidine urea material 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 and achieves a good balance between mechanical strength and network renewal speed.

[0041] In some preferred embodiments, the preparation method specifically includes the following steps: a uniformly mixed reaction system of an aliphatic guanidine amino acid monomer, a multifunctional isocyanate compound, and a solvent, firstly performing a pre-reaction, then removing the solvent, and then curing by gradient temperature increase to prepare a remodelable polyguanidine urea material of a bio-based aliphatic guanidine amino acid.

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

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

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

[0045] In some preferred embodiments, the preparation method comprises: uniformly mixing a guanidine-containing, carboxyl-containing bio-based amino acid, a multifunctional isocyanate compound, and a solvent to form the uniformly mixed reaction system.

[0046] Furthermore, 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 to (1 to 1.5), and the molar ratio of water to the organic solvent is 1:50 to 200.

[0047] In some preferred embodiments, the preparation method comprises: allowing the uniformly mixed reaction system to undergo a pre-reaction at 65 to 115° C. for 0.5 to 2 hours.

[0048] 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.

[0049] Furthermore, the curing process is one or more times of curing at 95-150° C. for 1-3 hours.

[0050] Furthermore, the remodelable polyguanidine urea material of the bio-based aliphatic guanidine amino acid is prepared by curing a guanidine- and carboxyl-containing bio-based amino acid and a multifunctional isocyanate compound in the absence of a catalyst.

[0051] In summary, the bio-based aliphatic guanidine amino acid remodelable polyguanidine urea material prepared by the present invention exhibits excellent thermal stability and mechanical properties, and at the same time, through the multi-level hydrogen bonds and non-covalent bonds in the structure, it has self-catalytic ability and can be quickly remodeled. It provides a new solution for the polyurea dynamic covalent polymer network and achieves a good balance between mechanical strength and network exchange speed.

[0052] As another aspect of the technical solution of the present invention, it involves a bio-based aliphatic 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.

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

[0054] Furthermore, the remodelable polyguanidine urea material of the bio-based aliphatic guanidine amino acid is hot-pressed at 100 to 140° C. for 5 to 60 minutes to achieve remodeling.

[0055] 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.

[0056] 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.

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

[0058] Example 1

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

[0060] Guanidine acetic acid, L-lysine diisocyanate, hexaethylene diisocyanate trimer, water: dimethyl sulfoxide are mixed in a three-necked flask at a molar ratio of 1:0.5:1:1:100; the mixed system is placed in a 90°C oil bath for pre-reaction for 1 hour, and the reaction is carried out under flowing nitrogen conditions; the pre-reaction product is placed in a 90°C vacuum oven for 1 hour to remove the solvent; then, the reactant is poured into a polytetrafluoroethylene mold, first cured at 110°C on a hot plate for 1 hour, and then cured at 150°C for 1 hour; after natural cooling, the following is obtained: Figure 1 The transparent light yellow film material is a polyguanidine urea material of bio-based aliphatic guanidine amino acid.

[0061] like Figure 2 As shown in the infrared spectrum of the polyguanidine urea material prepared in this embodiment, 3315 cm -1 The characteristic peak at is -CONH- absorption peak, 1637cm -1 The characteristic peak of -N-CO-N- is contributed by the formation of polyurea structure. In addition, the characteristic peak of C=O is contributed by the free 1700-1750cm -1 Migration to 1685cm in the figure -1 This change may be caused by the formation of intermolecular and intramolecular hydrogen bonds in the C=O of the acetyl group formed after the reaction, which also proves the success of the material synthesis.

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

[0063] After the polymer network material prepared in this example is cut into pieces, a flat plate vulcanizer is used to heat press at 120° C. for 20 minutes to obtain a complete material. Figure 1 , that is, the reshaped polyguanidine urea material, and the reshaped material is complete.

[0064] Example 2

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

[0066] L-arginine, benzyl 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 mixed system was placed in an 80°C oil bath for pre-reaction for 1 hour, and the reaction was carried out under flowing nitrogen conditions; the pre-reaction product was placed in a 90°C vacuum oven for evacuation to remove the solvent; then, the reactants were poured into a polytetrafluoroethylene mold, first cured at 100°C for 1 hour on a hot plate, then cured at 110°C for 1 hour, and then cured at 120°C for 1 hour; after natural cooling, a transparent light yellow film material was obtained.

[0067] The polyguanidine urea material prepared in this example 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 example is cut into pieces, it is hot-pressed at 140° C. for 10 minutes using a flat-plate vulcanizer to obtain a complete material again.

[0069] Example 3

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

[0071] Guanidine acetic acid, hexamethylene diisocyanate, water, and N,N-dimethylformamide are mixed in a three-necked flask at a molar ratio of 1:1:1:70; the mixed system is placed in a 95°C oil bath for pre-reaction for 1.5 hours, and the reaction is carried out under flowing nitrogen conditions; the pre-reaction product is placed in a 70°C vacuum oven for evacuation for 2 hours to remove the solvent; then, the reactant is poured into a polytetrafluoroethylene mold, first cured at 100°C on a hot plate, then cured at 110°C for 1 hour, and then cured at 120°C for 1 hour; after natural cooling, a transparent light yellow film material is obtained.

[0072] The polyguanidine urea material prepared in this example 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 example is cut into pieces, it is hot-pressed at 100° C. for 60 minutes using a flat plate vulcanizer to obtain a complete material again.

[0074] Example 4

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

[0076] Guanidine acetic acid, hexamethylene diisocyanate, water, and N,N-dimethylformamide are mixed in a three-necked flask at a molar ratio of 1:1:1:70; the mixed system is placed in a 95°C oil bath for pre-reaction for 1.5 hours, and the reaction is carried out under flowing nitrogen conditions; the pre-reaction product is placed in a 70°C vacuum oven for evacuation for 2 hours to remove the solvent; then, the reactant is poured into a polytetrafluoroethylene mold, first cured at 100°C on a hot plate, then cured at 110°C for 1 hour, and then cured at 120°C for 1 hour; after natural cooling, a transparent light yellow film material is obtained.

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

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

[0079] Example 5

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

[0081] 2-Guandinosuccinic 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 mixed system was placed in a 115℃ oil bath for pre-reaction for 2h, and the reaction was carried out under flowing nitrogen; 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 in a hot plate, and then cured at 150℃ for 1h; after natural cooling, a transparent light yellow film material was obtained.

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

[0083] 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.

[0084] Example 6

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

[0086] 6-Guanidocaproic 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 115°C oil bath for pre-reaction for 2 hours, and the reaction was carried out under flowing nitrogen conditions; the pre-reaction product was placed in a 70°C vacuum oven for 0.5 hours to remove the solvent; then, the reactants were 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.

[0087] The polyguanidine urea material prepared in this example 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 example is cut into pieces, it is hot-pressed at 120° C. for 30 minutes using a flat-plate vulcanizer to obtain a complete material again.

[0089] Comparative Example 1

[0090] Compared with Example 1, the difference between this comparative example and Example 1 is that guanidine acetic acid is replaced by a commercial raw material aliphatic polyurea (Gaodun N-100), and the other steps are the same to obtain a polyurea material.

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

[0092] Comparative Example 2

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

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

[0095] After the final material is cut into pieces, it needs to be hot-pressed at 160°C for 2 hours using a flat-plate vulcanizer to be reshaped, which is a slow process.

[0096] Comparative Example 3

[0097] Compared with Example 1, this comparative example only has a different molar ratio of raw materials, guanidine acetic acid, L-lysine diisocyanate, hexaethylene diisocyanate trimer, water: dimethyl sulfoxide according to 1: 0.5: 0.5: 1: 100, and other conditions are the same. The Young's modulus of the material is 784MPa and the tensile strength is 26.4Mpa. 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 polyguanidine urea material prepared in this comparative example is accelerated, but the mechanical properties are significantly reduced.

[0098] Comparative Example 4

[0099] Compared with Example 1, this comparative example only performed one curing during the curing process, and no secondary curing was performed, so the material could not be formed.

[0100] In summary, the present invention uses bio-based aliphatic guanidine amino acid and multifunctional isocyanate as raw materials to react to form guanidine urea structure and amide structure, and forms hydrogen bonds between molecules, which promotes the rapid exchange of dynamic covalent polymer network, so that the polyguanidine urea material can be reshaped in a relatively short time; at the same time, the multi-level hydrogen bonds within the material and between molecules and the π-π stacking between molecules to form non-covalent interactions can also increase the mechanical properties of the polymer network structure.

[0101] 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 bio-based aliphatic polyguanidine urea material, characterized in that: The bio-based aliphatic guanidine amino acid monomer and the multifunctional isocyanate compound are directly cross-linked without a catalyst to obtain a remodelable bio-based aliphatic polyguanidine urea material.

2. The method for preparing the bio-based aliphatic polyguanidine urea material according to claim 1, characterized in that: The specific steps include: The bio-based aliphatic guanidine amino acid monomer, the multifunctional isocyanate compound and the solvent are uniformly mixed to form a reaction system; The pre-reaction was carried out under a flowing nitrogen atmosphere; After removing the solvent, a curing reaction is carried out to obtain the aliphatic polyguanidine urea material.

3. The method for preparing the bio-based aliphatic polyguanidine urea material according to claim 1, characterized in that: The bio-based aliphatic guanidinyl amino acid monomer is a bio-based aliphatic guanidinyl carboxylic acid compound containing both guanidinyl and carboxyl functional groups; And / or, the bio-based aliphatic guanidine amino acid monomer includes any one or a combination of two or more of arginine, ornithine, 2-guanidinosuccinic acid, 2-guanidinoethylmercaptosuccinic acid, guanidinoacetic acid, guanidinopropionic acid, and 6-guanidinohexanoic acid; And / or, 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 method for preparing the bio-based aliphatic polyguanidine urea material according to claim 1, characterized in that: The solvent includes water, or a mixture of water and any one or a combination of several of ethanol, dimethyl sulfoxide, and N,N-dimethylformamide.

5. The method for preparing the bio-based aliphatic polyguanidine urea material 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 solvent is 1:50-200.

6. The method for preparing the bio-based aliphatic polyguanidine urea material according to claim 5, characterized in that: The pre-reaction comprises reacting at 65-115° C. for 0.5-2 h under a flowing nitrogen atmosphere.

7. The method for preparing the bio-based aliphatic polyguanidine urea material 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 2 to 3 times; And / or, the curing condition is curing at 95-150° C. for 1-3 hours.

8. A bio-based aliphatic polyguanidine urea material prepared by the preparation method according to any one of claims 1 to 7.

9. The bio-based aliphatic polyguanidine urea material according to claim 8, characterized in that: The bio-based aliphatic polyguanidine urea material can be reshaped by hot pressing at 100 to 140° C. for 5 to 60 minutes; And / or, the bio-based aliphatic polyguanidine urea material has a glass transition temperature of 90 to 120° C., an initial thermal degradation temperature of 200 to 270° C., a Young's modulus of 980 to 1750 MPa, and a tensile strength of 40.1 to 97.6 MPa.

10. Use of the bio-based aliphatic polyguanidine urea material according to any one of claims 8 to 9 in the field of waterproof and / or anti-corrosion materials.

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