Creep-resistant machinable environment-friendly high polymer material and preparation method thereof

Abstract

The invention belongs to the technical field of high polymer materials, and provides a creep-resistant processable environment-friendly high polymer material and a preparation method thereof.The preparation method comprises the steps that at least one polyfunctional acetoacetate compound reacts with at least one amine compound containing a primary amine group and / or a secondary amine group, and a vinyl amine ester dynamic covalent bond network is obtained; or, metal ions are introduced, so that the metal ions and nitrogen atoms and / or oxygen atoms existing in the polymer network form dynamic metal coordination bonds. Through multiple synergistic effects of a dynamic covalent bond, a dynamic metal coordinate bond and a hydrogen bond network of the vinyl amine ester, the material has excellent mechanical stability and creep resistance at a use temperature while maintaining reprocessability.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and relates to a creep-resistant, processable, and environmentally friendly polymer material and a preparation method thereof, and falls within the scope of recyclable and reshapeable thermosetting resins and their preparation methods. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] Existing dynamic network materials have weak resistance to permanent deformation (such as creep) during use, while practical applications often require materials to exhibit more rapid viscosity changes when cooling / heating.

[0004] Reversibly crosslinked polymers with vinylamine ester bonds as dynamic bonds exhibit an Arrhenius viscosity decrease with temperature, demonstrating excellent reprocessability. However, because the dynamic bonds can be exchanged at relatively low temperatures, the material's resistance to permanent deformation is low, making it susceptible to creep. To meet the creep performance requirements of materials in engineering applications, a new crosslinking network design is needed that significantly suppresses creep while maintaining reversible processability. Summary of the Invention

[0005] To address the above-mentioned issues, the present invention provides a creep-resistant, processable, and environmentally friendly polymer material and its preparation method. By designing a dynamically exchangeable VU crosslinked network involving adjacent amines and introducing metal-coordination bonds to create a dual crosslinked structure, the present invention aims to produce an environmentally friendly polymer material that combines high mechanical properties with excellent processability and creep resistance. Regarding material design, existing research generally believes that the rapid transamination of VU glass is highly dependent on the presence of free primary amines. Therefore, by masking the free primary amines within the system, the crosslinking network's exchange activity at low temperatures can be effectively reduced, thereby achieving low-temperature creep resistance. Furthermore, the introduced metal coordination bonds not only enhance the mechanical properties of the polymer network but also catalyze transamination at high temperatures, effectively improving the polymer's reprocessability at high temperatures. The present invention's mild preparation process and simplified steps facilitate industrial production, enabling the development of high-value-added, environmentally sustainable polymer materials for a variety of applications while reducing resource and energy consumption. Through the above-mentioned technical means and ideas, a feasible and efficient solution will be provided to solve the current problem that reversibly cross-linked polymer materials are difficult to balance creep resistance and excellent processing capabilities, and new ideas and support will be provided for the development of sustainable materials and circular economy.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The first aspect of the present invention provides a method for preparing a creep-resistant and processable environmentally friendly polymer material, comprising:

[0008] reacting at least one multifunctional acetoacetate compound with at least one amine compound comprising a primary amine group and / or a secondary amine group to obtain a vinylamine ester dynamic covalent bond network;

[0009] Alternatively, in the presence of metal ions, at least one multifunctional acetoacetate compound reacts with at least one amine compound containing a primary amine group and / or a secondary amine group to obtain a dynamic covalent bond network of vinylamine ester. At the same time, the metal ions form dynamic metal coordination bonds with nitrogen atoms and / or oxygen atoms present in the polymer network.

[0010] The present invention provides a creep-resistant and processable environmentally friendly polymer material, the core of which is to construct a unique multiple dynamic cross-linking network, which includes:

[0011] (a) A dynamic covalently bonded vinylamine (VU) network formed by the reaction of at least one multifunctional acetoacetate compound with at least one amine compound containing primary and / or secondary amine groups. The key strategy of this invention is to ensure that the free primary amine groups in the system are substantially consumed during initial network formation through stoichiometric control (e.g., using an excess of acetoacetate groups), while the secondary amine groups introduced into the network by specific polyamines (e.g., tetraethylenepentamine (TEPA)) actively participate in the subsequent dynamic exchange of VU bonds. This "neighboring amine participation" mechanism, particularly the participation of secondary amines, is crucial to the dynamic behavior of VU bonds.

[0012] (b) The metal ions introduced (such as Zn 2+ , and can be extended to Cu 2+ 、Fe 3+ Dynamic metal coordination bonds are formed with nitrogen atoms (e.g., from unreacted amine groups in TEPA or nitrogen in VU structures) and / or oxygen atoms (e.g., from carbonyl groups in acetoacetate structures or polyether segments) in the polymer network. These metal coordination bonds serve as a second level of dynamic crosslinking points, significantly enhancing the stability of the network at room temperature.

[0013] (c) A hydrogen bond network formed by the amine groups (secondary amines) in the polyamine components (especially TEPA) and / or the NH groups in the resulting vinylamine ester structure. These hydrogen bonds serve as physical crosslinking points, synergistically interacting with the VU covalent network and the metal coordination network to further enhance the mechanical properties and dimensional stability of the material at low temperatures, and may also modulate the exchange kinetics of the VU bonds.

[0014] The multiple synergistic effects of the dynamic covalent bonds, dynamic metal coordination bonds and hydrogen bond networks of the vinylamine ester of the present invention endow the material with excellent mechanical stability and creep resistance at the use temperature while maintaining reprocessability.

[0015] The second aspect of the present invention provides a creep-resistant and processable environmentally friendly polymer material prepared by the above method. The material is subjected to specific conditions (for example, D400@TEPA-10@Zn2 + 5% system can be hot pressed at 150℃ for 30 minutes to achieve hot pressing reprocessing. 2+ y% system, with Zn 2+ With the increase of the content (0% to 3%), the glass transition temperature (T g ) increases; when Zn 2+ When the content is further increased to 5%, Tg decreases slightly but is still higher than that of undoped Zn 2+ system.

[0016] The third aspect of the present invention provides applications of the aforementioned creep-resistant, processable, and environmentally friendly polymer material in the fields of structural bonding, electronic packaging, self-repairing materials, and flexible devices.

[0017] The polymer material of the present invention combines a double cross-linked network prepared by dynamic covalent bond exchange involving adjacent amines and a physical cross-linked structure formed by metal-coordination bonds. It has excellent thermal processing performance, mechanical stability and creep resistance, and is suitable for high-performance fields such as structural bonding, electronic packaging, self-healing materials, and flexible devices.

[0018] Beneficial effects of the present invention

[0019] (1) In the present invention, the multiple synergistic effects of the dynamic covalent bonds, dynamic metal coordination bonds and hydrogen bond networks of the vinylamine ester give the material excellent mechanical stability and creep resistance at the use temperature while maintaining reprocessability.

[0020] (2) The preparation method of the present invention is simple, practical, and easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their description are used to explain the present invention and do not constitute improper limitations on the present invention.

[0022] Figure 1Figures 2 and 3 show tensile stress-strain curves for different material systems according to some embodiments of the present invention. (a) shows the tensile stress-strain curves for the D400@TEPA-10 system at different ZnCl2 contents (e.g., 0%, 1%, 3%, and 5%); (b) shows the tensile stress-strain curves for the IPDA@TEPA-10 system at different ZnCl2 contents (e.g., 0%, 1%, 3%, and 5%).

[0023] Figure 2 Figure 2 shows the dynamic mechanical properties of different material systems in some embodiments of the present invention. (a) Stress relaxation curves of D400@TEPA-10 systems with different ZnCl2 contents at room temperature. (b) Changes in the glass transition temperature (Tg) of the D400@TEPA-10 system with ZnCl2 content. DETAILED DESCRIPTION

[0024] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0025] Unless otherwise defined, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. The reagents or raw materials used in the present invention can be purchased through conventional channels. Unless otherwise specified, the reagents or raw materials used in the present invention are used in accordance with conventional methods in the art or according to product specifications. Similarly, unless otherwise specified, the test methods of the present invention are also tested in accordance with conventional methods in the art or the common methods or standards in the industry. In addition, any methods and materials similar to or equivalent to the described contents can be applied to the inventive method. The preferred embodiments and materials described herein are for demonstration purposes only.

[0026] The present invention provides a method for preparing a creep-resistant and processable environmentally friendly polymer material, comprising:

[0027] reacting at least one multifunctional acetoacetate compound with at least one amine compound comprising a primary amine group and / or a secondary amine group to obtain a vinylamine ester dynamic covalent bond network;

[0028] Alternatively, in the presence of metal ions, at least one multifunctional acetoacetate compound reacts with at least one amine compound containing a primary amine group and / or a secondary amine group to obtain a dynamic covalent bond network of vinylamine ester. At the same time, the metal ions form dynamic metal coordination bonds with nitrogen atoms and / or oxygen atoms present in the polymer network.

[0029] In some embodiments, the multifunctional acetoacetate compound is a trifunctional acetoacetate polymer;

[0030] In some embodiments, bio-based trifunctional acetoacetate polymers derived from renewable resources, such as analogs synthesized from tall oil fatty acid and trimethylolpropane, may also be considered to enhance the environmental performance of the material.

[0031] In some embodiments, the amine compound is selected from at least one of a polyetheramine (such as polyetheramine D400), an alicyclic diamine (such as isophorone diamine (IPDA), and an aliphatic polyamine (such as tetraethylene pentamine (TEPA)). The introduction of TEPA not only provides primary and secondary amines for the formation and exchange of VU bonds, but the multiple nitrogen atoms in its structure also serve as key sites for metal coordination and hydrogen bond formation.

[0032] When the amine compound is mainly polyetheramine D400 and TEPA (for example, the mass ratio of D400 / TEPA is 90 / 10) and the ZnCl2 addition amount is 1-3wt%, the tensile strength and elongation at break of the material are improved;

[0033] Alternatively, when the amine compound is mainly isophorone diamine IPDA and TEPA (for example, the IPDA / TEPA mass ratio is 90 / 10) and the ZnCl2 addition amount is 1-5wt%, the initial modulus and tensile strength of the material are improved and the rigidity is enhanced.

[0034] In some embodiments, the molar ratio of the multifunctional acetoacetate compound to the amine compound is 1:0.95. The formation of the dynamic covalent bond of the vinylamine ester utilizes excess acetoacetate groups to ensure the consumption of free primary amine groups in the system, and the polymer network contains secondary amine groups introduced by amine compounds (such as TEPA) to participate in the dynamic exchange of vinylamine ester bonds.

[0035] In some embodiments, the reaction is carried out under heating conditions within the range of 50-120°C.

[0036] In some embodiments, the metal ion is selected from zinc ion, copper ion, and iron ion. The introduction of the metal ion accelerates the stress relaxation rate of the material under constant strain and catalyzes the transamination reaction of vinylamine ester at high temperatures (e.g., 110° C.), thereby improving the reprocessability of the material.

[0037] In some embodiments, the added amount of the metal ion is 0.1%-5% of the total mass of the amine compound.

[0038] More preferably, the metal ion is preferably zinc ion (Zn 2+ ), derived from zinc chloride (ZnCl2), can be added in an amount of 0.1% to 5% of the total mass of the amine compound. The present invention also covers other metal ions with similar coordination capabilities, such as copper ions (Cu 2+, such as from CuCl2) and iron ions (Fe 3+ , for example from FeCl3), which are expected to impart different catalytic activities, mechanical responses or colors to the materials.

[0039] In some embodiments, the metal ions are dissolved in the amine mixture.

[0040] More specifically, the following steps are included:

[0041] (a) dissolving at least one multifunctional acetoacetate compound (such as 3-AA) in an organic solvent (such as THF);

[0042] (b) preparing an amine mixture comprising at least one amine compound (such as D400, IPDA, TEPA or a mixture thereof), and optionally dissolving a metal salt (such as ZnCl2) in the amine mixture in a predetermined proportion;

[0043] (c) under controlled conditions (e.g., nitrogen protection, ≤25° C.), slowly adding the amine mixture to the solution of the multifunctional acetoacetate compound at a specific rate (e.g., 0.5 mL / min) to achieve a ratio of total amine group equivalents to acetoacetate group equivalents of a specific value (e.g., 0.95:1.0);

[0044] (d) reacting the mixture at a specific temperature (e.g., 40° C.) for a specific time (e.g., 24 hours) to form a prepolymer comprising vinylamine ester bonds and metal coordination centers;

[0045] (e) removing the solvent from the reaction solution (e.g., vacuum drying at 40° C. for 12 hours); and

[0046] (f) The dried prepolymer is subjected to programmed temperature curing (e.g., 60°C / 2h→80°C / 2h→100°C / 1h) to form the final polymer network.

[0047] The present invention also provides a method for preparing the polymer material, comprising mixing a multifunctional acetoacetate compound and an amine compound under specific conditions to form a polymer network containing vinylamine ester bonds, and then introducing a metal salt to form metal coordination bonds. The specific preparation process can be adjusted based on the selected raw materials and target performance.

[0048] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are intended to explain the present invention rather than to limit it.

[0049] Example 1: D400@TEPA-10 based system (0% ZnCl2)

[0050] In this example, polyetheramine D400 and tetraethylenepentamine TEPA (90 / 10 by mass) were reacted in the absence of ZnCl2 to prepare a vinylamine (VU) dynamic covalent network material. The core mechanism is that a trifunctional acetoacetate polymer (3-AA) reacts with the aforementioned amines, utilizing excess acetoacetate groups to ensure complete consumption of free primary amines. The dynamic nature of the network relies on the participation of secondary amines introduced by TEPA in VU bond exchange. The preparation process involves reacting 1.0 equivalents of 3-AA with a D400 / TEPA mixture containing 0.95 equivalents of total amino groups in THF at 40°C for 24 hours, followed by vacuum drying and programmed temperature curing (60°C / 2h → 80°C / 2h → 100°C / 1h). The obtained material exhibits flexibility. According to the GB / T 1040 standard test, the tensile strength is about 0.8 MPa and the elongation at break is about 150%; the stress relaxation ratio is about 6% after 300 seconds at room temperature. According to the ISO 527-2 standard, the tensile creep is tested and shows stable room temperature creep behavior (about 20% strain) under constant stress. No obvious creep behavior is found within a certain period of time; the glass transition temperature (Tg) is about -28.5°C tested by DSC.

[0051] Example 2: D400@TEPA-10, ZnCl2 doped 1%

[0052] In this example, 1% (based on the total mass of the amine mixture) of ZnCl2 was introduced into the D400@TEPA-10 amine system (D400 / TEPA mass ratio 90 / 10) to construct a dynamic covalent bond between VU and ZnCl2. 2v A dual dynamic network of metal coordination bonds. During preparation, ZnCl2 was pre-dissolved in methanol solution and then reacted with the D400 / TEPA mixture in THF at 40°C for 24 hours. The remaining steps (reaction of 3-AA with amine, solvent removal, and curing) were similar to those in Example 1. After the introduction of 1% ZnCl2, the tensile strength of the material increased to about 1.0 MPa, and the elongation at break increased significantly to about 280%, achieving the dual effects of strengthening and toughening. Zn 2+ The addition of Zn accelerates the stress relaxation rate at 110°C and shows a higher initial creep strain (about 45%) than the 0% Zn sample in the room temperature creep test, but then tends to stabilize. The Tg of the material is also affected by Zn. 2+ The coordination was slightly increased to -24.3℃, and FT-IR confirmed that Zn2 + Coordinates with N / O atoms and affects the hydrogen bond network.

[0053] Example 3: D400@TEPA-10, ZnCl2 doped 5%

[0054] This embodiment uses the D400@TEPA-10 amine system and dopes it with a higher concentration of 5% ZnCl2 to maximize the regulatory effect of the metal coordination bond on the dual dynamic network, especially to enhance the high-temperature dynamic characteristics to improve reprocessability. The preparation method is similar to that of Example 2, except that the ZnCl2 content is different. The introduction of 5% ZnCl2 makes the tensile strength of the material reach about 1.4MPa, and the elongation at break increases significantly to about 500%, showing a significant toughening effect. The stress relaxation ratio of the system within 300 seconds at room temperature is as high as 30%, and the stress relaxation rate is fastest at 110°C, showing that Zn 2+ Although the initial strain of tensile creep at room temperature is the highest (about 78%), it can still be stable; the shear creep strain at high temperature (120℃) also increases significantly. 2+ When the content is high (such as 0.5% mentioned in the PDF, which is consistent with the trend of 5% here), the material shows excellent cyclic tensile stability and self-recovery ability. Its Tg is about -25.6℃, and the material shows good hot pressing reprocessing performance at 150℃. SEM observation of high concentration of Zn 2+ May cause aggregation.

[0055] Example 4: IPDA@TEPA-10 based system (0% ZnCl2)

[0056] In this embodiment, isophorone diamine (IPDA) and TEPA (mass ratio 90 / 10) are used to construct a VU dynamic network with rigid IPDA as the main body under ZnCl2 conditions. IPDA gives the network a high initial modulus and strength, while the introduction of TEPA is intended to reconcile the system rigidity through its polyamine structure and hydrogen bond network and provide a basis for subsequent modification. The preparation steps are similar to those in Example 1, except that the amine components are different, including the reaction of 3-AA with an IPDA / TEPA mixed amine solution, solvent removal, and curing. Compared to the pure IPDA system, the IPDA@TEPA-10 system (0% Zn) significantly increases its elongation at break to about 700% while maintaining a high strength (tensile strength of approximately 25 MPa), demonstrating the effective toughening effect of TEPA on the rigid system.

[0057] Example 5: IPDA@TEPA-10, ZnCl2 doped 3%

[0058] In this example, 3% ZnCl2 was introduced into the rigid IPDA@TEPA-10 amine system (IPDA / TEPA mass ratio 90 / 10) to construct a dual dynamic network, aiming to utilize Zn2 +The coordination further enhances the crosslinking density, rigidity and strength of the network. The preparation process is similar to that of Example 2, using an IPDA / TEPA amine mixture and adding 3% ZnCl2. The results show that in the IPDA-based rigid system, after adding 3% ZnCl2, the initial modulus and tensile strength of the material are significantly improved (strength exceeds 30MPa), while the elongation at break is correspondingly reduced (about 50-100%), showing a significant rigidification effect, which is consistent with the ZnCl2 addition. 2+ The toughening effect in the flexible D400 system is in contrast.

[0059] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for preparing a creep-resistant and processable environmentally friendly polymer material, characterized in that: include: reacting at least one multifunctional acetoacetate compound with at least one amine compound comprising a primary amine group and / or a secondary amine group to obtain a vinylamine ester dynamic covalent bond network; Alternatively, in the presence of metal ions, at least one multifunctional acetoacetate compound reacts with at least one amine compound containing a primary amine group and / or a secondary amine group to obtain a dynamic covalent bond network of vinylamine ester. At the same time, the metal ions form dynamic metal coordination bonds with nitrogen atoms and / or oxygen atoms present in the polymer network.

2. The method for preparing the creep-resistant and processable environmentally friendly polymer material according to claim 1, wherein: The multifunctional acetoacetate compound is a trifunctional acetoacetate polymer; Alternatively, the multifunctional acetoacetate compound is a trifunctional acetoacetate polymer analogue synthesized from tall oil fatty acid and trimethylolpropane.

3. The method for preparing the creep-resistant and processable environmentally friendly polymer material according to claim 1, wherein: The amine compound is selected from at least one of polyetheramine, alicyclic diamine, and aliphatic polyamine.

4. The method for preparing the creep-resistant and processable environmentally friendly polymer material according to claim 1, wherein: The molar ratio of the multifunctional acetoacetate compound to the amine compound is 1:0.

95.

5. The method for preparing the creep-resistant and processable environmentally friendly polymer material according to claim 1, wherein: The reaction conditions are heating within 50-120°C.

6. The method for preparing the creep-resistant and processable environmentally friendly polymer material according to claim 1, wherein: The metal ion is selected from one of zinc ion, copper ion and iron ion.

7. The method for preparing a creep-resistant and processable environmentally friendly polymer material according to claim 1, wherein: The added amount of the metal ions is 0.1%-5% of the total mass of the amine compound.

8. The method for preparing the creep-resistant and processable environmentally friendly polymer material according to claim 1, wherein: The metal ions are dissolved in the amine mixture.

9. The creep-resistant, processable, and environmentally friendly polymer material prepared by the method according to any one of claims 1 to 8.

10. Application of the creep-resistant, processable, and environmentally friendly polymer material according to claim 9 in the fields of structural bonding, electronic packaging, self-repairing materials, and flexible devices.

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