Force self-adaptive polymer network based on force chromophore and rotaxane as well as preparation method and application of force self-adaptive polymer network

Abstract

The invention discloses a force self-adaptive polymer network based on a force chromophore and rotaxane, a preparation method of the force self-adaptive polymer network and application of the force self-adaptive polymer network in a flexible material. The force self-adaptive polymer network based on the mechanochromic group and the rotaxane is obtained through reaction of raw materials including the mechanochromic group, polytetrahydrofuran, an isocyanate monomer and a rotaxane monomer. The force self-adaptive polymer network is prepared by combining the force chromophore and rotaxane which are subjected to reverse ring-opening reaction under the action of force, and has application potential in the fields of flexible electronics, buffer materials, drug release, toughening agents and the like.

Description

Technical Field

[0001] The present invention relates to the field of intelligent response materials, and in particular to a force-adaptive polymer network based on force chromophores and rotaxanes, and a preparation method and application thereof. Background Art

[0002] Polymer materials have been widely used in key fields such as life sciences, construction engineering, and aerospace due to their unique performance advantages. With the continuous increase in application demand, the development of polymer materials with excellent performance has become an important research direction. However, traditional polymer materials often face limitations in mechanical properties in practical applications, mainly manifested in deformation and fracture problems under stress conditions, which not only limits their scope of application, but also affects the service life of the material.

[0003] From the perspective of molecular mechanisms, the macroscopic damage behavior of polymer materials mainly originates from the breaking of their covalent bonds. Studies have shown that by introducing specific low-bond energy groups (i.e., mechanochromophores) into the molecular structure, the mechanical response characteristics of the material can be effectively regulated. Taking cinnamic acid dimers as an example, this type of mechanochromophore can undergo a reverse ring-opening reaction when subjected to stress. When this type of mechanochromophore is integrated into the polymer network, the local tension can be effectively relieved through a reverse ring-opening reaction under stress, thereby significantly improving the material's tear resistance, tensile properties and toughness (Macromolecules 2025, 58, 4; Science 2023, 380, 1248).

[0004] In the field of supramolecular chemistry, mechanically interlocked molecules (such as rotaxanes) have attracted much attention due to their unique topological structures. This type of molecular system consists of linear molecules inserted into macrocyclic molecules, where the macrocyclic ring can slide freely on the linear molecules. Of particular note is the rotaxane system constructed with crown ether-quaternary ammonium salt as the host-guest recognition unit. When this type of rotaxane structure is introduced into the polymer backbone, the crown ether ring and the quaternary ammonium salt axis first dissociate under stress, and then the crown ether ring slides axially and releases the hidden segment. This unique molecular mechanism gives the material excellent ductility and energy dissipation properties (Acc. Chem. Res. 2024, 57, 992; Angew. Chem. Int. Ed. 2025, 64, e202422104).

[0005] Although the introduction of mechanochromophores and rotaxanes can significantly improve the ductility and energy dissipation capacity of polymers, there is still a lack of systematic research on the synergistic effect of the two in the same polymer system. Exploring the synergistic mechanism of mechanochromophores and rotaxanes and achieving unexpected performance improvement effects will provide new theoretical guidance and technical approaches for the further development of high-performance polymer materials. Summary of the invention

[0006] The present invention provides a force-adaptive polymer network based on a mechanochromophore and a rotaxane, a preparation method thereof, and an application in flexible materials. The present invention combines a mechanochromophore and a rotaxane that undergo a reverse ring-opening reaction under the action of a force to prepare a force-adaptive polymer network, which has application potential in the fields of flexible electronics, buffer materials, drug release, toughening agents, and the like.

[0007] The specific technical solutions are as follows:

[0008] [1] A mechano-adaptive polymer network based on a mechanochromophore and a rotaxane, obtained by reacting raw materials including a mechanochromophore, polytetrahydrofuran, an isocyanate monomer and a rotaxane monomer;

[0009] The chromophore has the structure shown below:

[0010]

[0011] The rotaxane monomer has the structure shown below:

[0012]

[0013] In the present invention, the force chromophore is a prior art, and specific references may be made to the literature Science 2023, 380, 1248, DOI: 10.1126 / science.adg3229, etc.

[0014] In the present invention, the rotaxane monomer is a prior art, and details can be found in references such as Fundamental Research 4 (2024) 300-306.

[0015] In the force-adaptive polymer network based on force chromophore and rotaxane, the number average molecular weight of the polytetrahydrofuran can be 1000-2000 g / mol.

[0016] In the force-adaptive polymer network based on force chromophore and rotaxane, the isocyanate monomer may include one or more of hexamethylene diisocyanate, 4,4'-methylenebis(phenyl isocyanate), and isophorone diisocyanate.

[0017] In some preferred examples, in the force-adaptive polymer network based on force chromophore and rotaxane, in the raw materials, the total molar number of hydroxyl groups of the force chromophore, polytetrahydrofuran and rotaxane monomers is equal to the total molar number of NCO groups of the isocyanate monomers.

[0018] The force-adaptive polymer network based on force chromophore and rotaxane, in the raw material, the molar ratio of the force chromophore and the rotaxane monomer can be 3:1-9, preferably 1:0.5-2, and further preferably 1:1. Under the preferred conditions, the Young's modulus, maximum strain, maximum stress and toughness of the obtained polymer network are better.

[0019] The force-adaptive polymer network based on force chromophore and rotaxane, in the raw materials, taking the total molar number of force chromophore, polytetrahydrofuran and rotaxane monomer as 100%, the sum of the molar numbers of the force chromophore and the rotaxane monomer may account for 30% to 50%, for example 40%.

[0020] [2] The method for preparing a force-adaptive polymer network based on a force chromophore and a rotaxane according to [1], comprising:

[0021] Under an inert atmosphere, polytetrahydrofuran, isocyanate monomer, rotaxane monomer, mechanochromophore, reaction solvent and a catalyst that may be optionally added are mixed and reacted. After the reaction, the resulting mixture is further solidified and excess reaction solvent is removed to obtain the mechanochromophore- and rotaxane-based mechanoadaptive polymer network.

[0022] In the method for preparing a force-adaptive polymer network based on force chromophores and rotaxanes, the inert atmosphere refers to an atmosphere that does not participate in the reaction, and may be a nitrogen atmosphere or the like.

[0023] In the method for preparing the force-adaptive polymer network based on force chromophore and rotaxane, the reaction solvent may be an organic solvent. Further, the organic solvent may include at least one of dichloromethane (DCM), tetrahydrofuran, acetonitrile, and acetone.

[0024] In the method for preparing the force-adaptive polymer network based on force chromophore and rotaxane, the catalyst may include dibutyltin dilaurate.

[0025] In the method for preparing the force-adaptive polymer network based on force chromophore and rotaxane, the temperature of the mixing reaction can be room temperature to 70°C.

[0026] In the method for preparing the force-adaptive polymer network based on force chromophore and rotaxane, the mixing reaction time can be 24 to 48 hours.

[0027] In the method for preparing the force-adaptive polymer network based on force chromophore and rotaxane, after the reaction is completed, the obtained mixed solution can be placed in a vacuum oven for further solidification and removal of excess reaction solvent.

[0028] In the method for preparing the force-adaptive polymer network based on force chromophore and rotaxane, the curing temperature can be 55-65°C, such as 60°C.

[0029] In the method for preparing the force-adaptive polymer network based on force chromophore and rotaxane, the curing time can be 24 to 30 hours.

[0030] [3] Application of the force-adaptive polymer network based on mechanochromophore and rotaxane according to [1] or the force-adaptive polymer network based on mechanochromophore and rotaxane prepared according to the preparation method of [2] in flexible materials. The force-adaptive polymer network exhibits mechanical properties superior to those of a single system and is expected to be applied in the fields of flexible electronics, cushioning materials, drug release, toughening agents, etc.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The force-adaptive polymer network based on mechanochromophore and rotaxane of the present invention has outstanding energy dissipation capacity, ductility, toughness, maximum stress and other properties, which are superior to a single mechanochromophore-based polymer network or a single rotaxane-based polymer network.

[0033] 2. The force-adaptive polymer network based on force chromophore and rotaxane provided by the present invention is expected to exert new functions and broaden application scenarios.

[0034] 3. The method for preparing a force-adaptive polymer network based on force chromophore and rotaxane provided by the present invention is simple to operate, has a reliable route and is low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of the synthesis route of the force-adaptive polymer network AC based on force chromophore and rotaxane in a specific embodiment.

[0036] Figure 2 1. The morphological photograph of the force adaptive polymer network AC based on the force chromophore and the rotaxane in a specific embodiment (A) and the infrared comparison result of the force adaptive polymer network A based on the force chromophore and the rotaxane and the force chromophore and the rotaxane monomer (B).

[0037] Figure 3 1 is a stress-strain test curve diagram of the force-adaptive polymer network AC based on force chromophore and rotaxane at a stretching rate of 100 mm / min in a specific embodiment (A), and a comparison diagram of the maximum stress (B) and toughness (C) results read therefrom.

[0038] Figure 4 It is a stress-strain test curve diagram (A) of the force-adaptive polymer network A based on force chromophore and rotaxane and its control polymer networks Con-1 and Con-2 at a stretching rate of 100 mm / min in Example 1, as well as a comparison diagram of the maximum stress (B) and toughness (C) results read therefrom.

[0039] Figure 5The figures are as follows: graphs of the cyclic stress-strain test results of the force-adaptive polymer network A (A) based on force chromophores and rotaxanes in Example 1 over a wide range of maximum applied strains from 200% to 1200% and graphs of the cyclic stress-strain test results of its control polymer networks Con-1 (B) and Con-2 (C) over a wide range of maximum applied strains from 200% to 600%.

[0040] Figure 6 This is a comparison chart of the energy dissipation values ​​of the force-adaptive polymer network A based on force chromophore and rotaxane in Example 1 and its control polymer networks Con-1 and Con-2 under increasing strain cyclic stretching.

[0041] Figure 7 This is a graph showing the results of cyclic stress-strain testing of a force-adaptive polymer network A based on mechanochromophore and rotaxane in Example 1 without any interval within a fixed strain range (A) and a graph showing the results of cyclic stress-strain testing with different rest times within a fixed strain range (B). DETAILED DESCRIPTION

[0042] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0043] In the present invention, the stress-strain curves are measured at room temperature at a constant tensile rate of 100 mm / min. Young's modulus is determined by the initial slope of the stress-strain curve. Toughness is a parameter that characterizes the work required for the fracture of each unit sample, and is calculated based on the area below the stress-strain curve (until fracture). Energy dissipation is calculated by integrating the area contained in the cyclic tensile curve.

[0044] The number average molecular weight of the polytetrahydrofuran used in the following examples is 1000 g / mol.

[0045] Embodiment 1:

[0046] Combination Figure 1 , Synthesis of force-adaptive polymer network A (MMN-A) based on mechanochromophore and rotaxane:

[0047] Under nitrogen, polytetrahydrofuran (PTHF, 0.30 mmol), rotaxane monomer (0.10 mmol), force chromophore (0.10 mmol), hexamethylene diisocyanate (0.50 mmol) and reaction solvent DCM (2 mL) were added to the reaction bottle, and a drop of dibutyltin dilaurate was used as a catalyst. The system was stirred and reacted for 1 day. The obtained mixed solution was poured into a mold and placed in a vacuum oven at 60°C for 24 hours to further solidify the sample and remove excess solvent. After taking out the sample and cooling it to room temperature, a force adaptive polymer network A (MMN-A) based on force chromophore and rotaxane was obtained.

[0048] Comparative Example 1:

[0049] Under nitrogen, polytetrahydrofuran (0.20 mmol), chromophore (0.10 mmol), hexamethylene diisocyanate (0.30 mmol) and reaction solvent DCM (2 mL) were added to the reaction bottle, and a drop of dibutyltin dilaurate was used as a catalyst. The system was stirred and reacted for 1 day. The obtained mixed solution was poured into a mold and placed in a vacuum oven at 60°C for 24 hours to further solidify the sample and remove excess solvent. After taking out the sample and cooling it to room temperature, the chromophore-based polymer network Con-1 was obtained.

[0050] Comparative Example 2:

[0051] Under nitrogen, polytetrahydrofuran (0.20 mmol), rotaxane monomer (0.10 mmol), hexamethylene diisocyanate (0.30 mmol) and reaction solvent DCM (2 mL) were added to the reaction bottle, and a drop of dibutyltin dilaurate was used as a catalyst. The system was stirred and reacted for 1 day. The obtained mixed solution was poured into a mold and placed in a vacuum oven at 60°C for 24 hours to further solidify the sample and remove excess solvent. After taking out the sample and cooling it to room temperature, the rotaxane-based polymer network Con-2 was obtained.

[0052] Embodiment 2:

[0053] Combination Figure 1 , Synthesis of mechano-adaptive polymer network B (MMN-B) based on mechanochromophore and rotaxane:

[0054] Under nitrogen, polytetrahydrofuran (0.30 mmol), rotaxane monomer (0.05 mmol), force chromophore (0.15 mmol), hexamethylene diisocyanate (0.50 mmol) and reaction solvent DCM (2 mL) were added to the reaction bottle, and a drop of dibutyltin dilaurate was used as a catalyst. The system was stirred and reacted for 1 day. The obtained mixed solution was poured into a mold and placed in a vacuum oven at 60°C for 24 hours to further solidify the sample and remove excess solvent. After taking out the sample and cooling it to room temperature, a force adaptive polymer network B (MMN-B) based on force chromophore and rotaxane was obtained.

[0055] Embodiment 3:

[0056] Combination Figure 1 , Synthesis of force-adaptive polymer network C (MMN-C) based on mechanochromophore and rotaxane:

[0057] Under nitrogen, polytetrahydrofuran (0.30 mmol), rotaxane monomer (0.15 mmol), force chromophore (0.05 mmol), hexamethylene diisocyanate (0.50 mmol) and reaction solvent DCM (2 mL) were added to the reaction bottle, and a drop of dibutyltin dilaurate was used as a catalyst. The system was stirred and reacted for 1 day. The obtained mixed solution was poured into a mold and placed in a vacuum oven at 60°C for 24 hours to further solidify the sample and remove excess solvent. After taking out the sample and cooling it to room temperature, a force adaptive polymer network C (MMN-C) based on force chromophore and rotaxane was obtained.

[0058] Figure 1 An exemplary synthesis schematic diagram of the force-adaptive polymer network based on the force chromophore and the rotaxane of the present invention is shown, and the force-adaptive polymer network based on the force chromophore and the rotaxane is obtained in a one-pot method by reacting the hydroxyl groups in the rotaxane monomer, the hydroxyl groups in the force chromophore, the hydroxyl groups in polytetrahydrofuran and hexamethylene diisocyanate (HDI).

[0059] Sample Analysis:

[0060] The polymer networks prepared in Examples 1-3 were subjected to performance tests. Figure 2 A is a solid photograph of the force-adaptive polymer network based on force chromophore and rotaxane obtained in Examples 1-3, combined with Figure 2 From the infrared spectrum of MMN-A in B, it can be seen that the characteristic peaks of the force chromophore and the rotaxane monomer are both reflected in the polymer network MMN-A, indicating that the force adaptive polymer network was successfully prepared. Figure 3 This is a stress-strain curve of the polymer network AC prepared in Example 1-3. It can be seen that when the molar ratio of the mechanochromophore and the rotaxane is 1:1, the Young's modulus, maximum strain, maximum stress and toughness of the network are the best. Figure 4 The stress-strain curves of the polymer network A prepared in Example 1 and the two control polymer networks Con-1 and Con-2 are shown in the figure. It can be seen from the figure that the Young's modulus, maximum strain, maximum stress and toughness of the polymer network A are far superior to those of the two control polymer networks Con-1 and Con-2, indicating that the mechanochromophore and the rotaxane can play a role in the system at the same time. Figure 5 and Figure 6 The cyclic tensile curves with increasing strain for the polymer network A prepared in Example 1 and the two control polymer networks Con-1 and Con-2 show that the energy dissipation capacity of the polymer network A is always stronger than that of the two control polymer networks Con-1 and Con-2, and as the strain increases, the hysteresis loop of the polymer network becomes larger, further illustrating that the mechanochromophore and the rotaxane can play a role in the system at the same time. Figure 7 A. Figure 7B are the cyclic tensile curves with and without interval time at fixed strain. It can be seen from the figure that obvious hysteresis loop and residual strain appear in the first cycle. The curves without interval are basically overlapped after 4 repetitions, indicating that the material has certain fatigue resistance. The cyclic tensile curve after 1h interval shows that the mechanical properties of the material can be restored after a period of rest.

[0061] In addition, it should be understood that after reading the above description of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

1. A force-adaptive polymer network based on a force chromophore and a rotaxane, characterized in that: It is obtained by reacting raw materials including a chromophore, polytetrahydrofuran, an isocyanate monomer and a rotaxane monomer; The chromophore has the structure shown below: The rotaxane monomer has the structure shown below:

2. The force-adaptive polymer network based on force chromophore and rotaxane according to claim 1, characterized in that: The number average molecular weight of the polytetrahydrofuran is 1000-2000 g / mol.

3. The force-adaptive polymer network based on force chromophore and rotaxane according to claim 1, characterized in that: The isocyanate monomer includes one or more of hexamethylene diisocyanate, 4,4'-methylenebis(phenyl isocyanate), and isophorone diisocyanate.

4. The force-adaptive polymer network based on force chromophore and rotaxane according to claim 1, characterized in that: In the raw materials, the total molar number of hydroxyl groups of the chromophore, polytetrahydrofuran and rotaxane monomers is equal to the total molar number of NCO groups of the isocyanate monomers.

5. The force-adaptive polymer network based on force chromophore and rotaxane according to claim 1, characterized in that: In the raw material, the molar ratio of the chromophore to the rotaxane monomer is 3:1-9, preferably 1:0.5-2, and more preferably 1:1; In the raw materials, based on the total molar number of the chromophore, polytetrahydrofuran and the rotaxane monomer as 100%, the sum of the molar numbers of the chromophore and the rotaxane monomer accounts for 30% to 50%.

6. The method for preparing a force-adaptive polymer network based on a force chromophore and a rotaxane according to any one of claims 1 to 5, characterized in that: include: Under an inert atmosphere, polytetrahydrofuran, isocyanate monomer, rotaxane monomer, mechanochromophore, reaction solvent and a catalyst that may be optionally added are mixed and reacted. After the reaction, the resulting mixture is further solidified and excess reaction solvent is removed to obtain the mechanochromophore- and rotaxane-based mechanoadaptive polymer network.

7. The preparation method according to claim 6, characterized in that: The inert atmosphere is a nitrogen atmosphere; The reaction solvent is an organic solvent; the organic solvent includes at least one of dichloromethane, tetrahydrofuran, acetonitrile and acetone; The catalyst includes dibutyltin dilaurate; The temperature of the mixed reaction is room temperature to 70°C; The mixing reaction time is 24 to 48 hours; After the reaction is completed, the resulting mixture is placed in a vacuum oven for further solidification and removal of excess reaction solvent; The curing temperature is 55-65°C; The curing time is 24 to 30 hours.

8. Use of the force-adaptive polymer network based on a force chromophore and a rotaxane according to any one of claims 1 to 5 or the force-adaptive polymer network based on a force chromophore and a rotaxane prepared according to the preparation method according to claim 6 or 7 in flexible materials.

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