Preparation method and application of Schiff base multi-crosslinking polyurethane and polyurethane-based solid ionic conductor

Abstract

The invention discloses a preparation method and application of Schiff base multi-crosslinking polyurethane and a polyurethane-based solid ionic conductor, and the Schiff base multi-crosslinking polyurethane is prepared from the following main raw materials in parts by weight: 20-30 parts of polytetramethylene ether glycol, 40-60 parts of diisocyanate, 40-60 parts of a chain extender, 1-3 parts of a catalyst and 40-60 parts of a crosslinking agent. And 35 to 50 parts of a hexamethylene diisocyanate tripolymer curing agent. The polyurethane-based solid ionic conductor is prepared from the following main raw materials in parts by weight: 120 parts of lithium bis (trifluoromethane sulfonimide) and 100 parts of Schiff base multi-crosslinking polyurethane. The polyurethane solid ionic conductor has excellent mechanical properties and ionic conductivity, has excellent sensing stability and sensitivity when being applied to a flexible sensor and a multi-mode sensor, and has excellent accuracy when being used as a sensing assembly of a driving behavior sensor.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer synthesis, and specifically to a preparation method and application of Schiff base multiple cross-linked polyurethane and polyurethane-based solid ion conductor. Background Art

[0002] With the rapid development of flexible electronic technology, flexible sensors, as a key component thereof, have been widely used in fields such as health monitoring, intelligent wearables, and environmental perception. The core requirements of flexible sensors are good mechanical flexibility and high sensitivity, which makes the selection of conductive materials particularly important. As a new type of conductive material, solid ion conductor materials have attracted extensive attention in recent years due to their good mechanical flexibility and high ionic conductivity. Compared with traditional electronic conductors, solid ion conductors can not only maintain good conductive performance under large deformation and large stretching conditions, but also exhibit more stable sensing performance in different external environments. Currently, some solid ion conductor materials have been explored for the design and preparation of flexible sensors. These materials mainly rely on the ion conduction mechanism to achieve changes in electrical signals through ion migration, thereby achieving the sensing purpose. However, existing solid ion conductor materials still have some defects. For example, although some materials have excellent mechanical properties, their conductive performance is prone to decline under large deformation, resulting in unstable sensing performance. There are also some materials that have high ionic conductivity, but their mechanical flexibility is poor, making it difficult to meet the working requirements of flexible sensors under large deformation or high strain conditions.

[0003] Therefore, developing solid ion conductor materials that not only have good mechanical properties but also can maintain stable conductive performance under large deformation conditions is still an important topic in the field of flexible sensors. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a preparation method and application of Schiff base multiple cross-linked polyurethane and polyurethane-based solid ion conductor. The Schiff base multiple cross-linked polyurethane obtained by the method of the present invention has excellent mechanical properties and ionic conductivity. The polyurethane-based solid ion conductor obtained by the method of the present invention has both service stability and biological safety, and at the same time has high ionic conductivity and high mechanical properties. Applying the polyurethane-based solid ion conductor to flexible sensors and multimodal sensors has excellent sensing stability and sensitivity, and has excellent accuracy as a sensing component of a driving behavior sensor.

[0005] The present invention solves the above technical problems with the following technical solutions:

[0006] Invention 1, the structural formula of the Schiff base multiple cross-linked polyurethane of the present invention is shown in Formula 1:

[0007]

[0008] In the formula

[0009] R2 = R4 or R5 or R6

[0010]

[0011] R3 = R7 or R8 or R9

[0012]

[0013] The preparation method of the Schiff base multi-crosslinked polyurethane of the present invention is as follows:

[0014] The required main raw materials are proportioned by weight as follows: 20-30 parts of polytetramethylene ether glycol, 40-60 parts of diisocyanate, 40-60 parts of chain extender, 1-3 parts of catalyst, 40-60 parts of crosslinking agent, and 35-50 parts of hexamethylene diisocyanate trimer curing agent;

[0015] The preparation process is as follows:

[0016] (1) Heat the polytetramethylene ether glycol placed in a three-necked flask to 90-120 °C in a vacuum environment, keep stirring for 30-60 min, and then cool down to 60-90 °C;

[0017] (2) Dissolve the diisocyanate in an anhydrous organic solvent, and then add it to the three-necked flask in step (1) under a nitrogen atmosphere;

[0018] (3) Add the catalyst to the three-necked flask in step (2), keep the reaction at 60-90 °C for 4-8 hours, then dissolve the chain extender in an anhydrous organic solvent and add it to the three-necked flask in step (2), and keep the reaction at 60-90 °C for 8-14 hours;

[0019] (4) Dissolve the crosslinking agent in an anhydrous organic solvent, and then add it to the three-necked flask in step (3), and keep stirring at 50-90 °C for 8-14 hours;

[0020] (5) Dissolve the triisocyanate curing agent in an anhydrous organic solvent, and then add it to the three-necked flask in step (4), and keep stirring at 60-90 °C for 8-14 hours to obtain the Schiff base multi-crosslinked polyurethane.

[0021] The catalyst of the present invention is dibutyltin dilaurate (DBTDL) or tin dilaurate (DBTO).

[0022] The chain extender of the present invention is a tetrafunctional aromatic compound, including two aldehyde groups and two hydroxyl groups, and its structural formula is as

[0023] As shown in Formula 2:

[0024]

[0025] The structural formula of the hexamethylene diisocyanate trimer curing agent described in the present invention is as shown in Formula 3:

[0026]

[0027] In step 2-5 of the present invention, the anhydrous organic solvent is N,N-dimethylacetamide (DMAC) or N,N-dimethylformamide (DMF), and the amount used is appropriate to achieve dissolution.

[0028] The diisocyanate described in the present invention is hexamethylene diisocyanate or dicyclohexylmethane 4,4'-diisocyanate or isophorone diisocyanate.

[0029] The crosslinking agent described in the present invention is p-phenylenediamine or isophthalic dihydrazide or adipic dihydrazide.

[0030] Invention 2. The preparation method of the polyurethane-based solid-state ion conductor of the present invention is as follows:

[0031] The main raw materials required are in a weight ratio of: 120 parts of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 100 parts of polyurethane; the polyurethane used is a Schiff base multi-crosslinked polyurethane;

[0032] The preparation process is as follows: Dissolve lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in an anhydrous organic solvent and mix it with polyurethane for 4 hours to obtain a mixed solution, and then place the mixed solution on a hot plate at 80-90°C to evaporate the solvent to obtain a polyurethane-based ion-conductive elastomer; the anhydrous organic solvent is N,N-dimethylacetamide (DMAC) or N,N-dimethylformamide (DMF), and the amount used is appropriate to achieve dissolution.

[0033] Invention 3. The application of the polyurethane-based solid-state ion conductor of the present invention: The polyurethane-based solid-state ion conductor is used to manufacture the sensing components of flexible sensors or multi-modal sensors or driving behavior sensors.

[0034] The chemical reaction equation for the synthesis of the Schiff base multi-crosslinked polyurethane described in the present invention is as shown in the following formula:

[0035]

[0036] The present invention has the following beneficial effects:

[0037] (1) By introducing multiple crosslinking sites into the polyurethane hard segments, the present invention enables the maintenance of a certain microphase separation domain even when the intermolecular interactions in the polymer chains are disrupted after the introduction of lithium salts, providing mechanical strength for the polyurethane-based solid-state ion conductor. Meanwhile, the polyether segments in the soft phase not only improve the toughness of the material but also can transport Li + , laying a foundation for improving the ionic conductivity of the material.

[0038] (2) The polyurethane solid-state ion conductor prepared by the hard phase enrichment strategy of the present invention exhibits high mechanical properties (3.5 MPa) and ultra-high ionic conductivity (4.9×10 -4 S cm -1 ), and at the same time has excellent resilience and sensing stability.

[0039] (3) By introducing a multi-crosslinking system, the polyurethane-based solid-state ion conductor of the present invention has a certain phase separation structure, which helps to improve the mechanical properties and can accommodate a high concentration of conductive components. With the synergistic effect of polytetramethylene ether glycol, it has high ionic conductivity.

[0040] (4) Due to the synergistic gain of multiple crosslinking interactions, the polyurethane-based solid-state ion conductor has excellent comprehensive properties and can be used to construct flexible sensor devices with microstructures. Applying the polyurethane-based solid-state ion conductive elastomer to flexible sensors and multi-modal sensors has excellent sensing stability and sensitivity, and has excellent accuracy as a sensing component of a driving behavior sensor. Description of the Drawings

[0041] Figure 1 Infrared spectrum of the Schiff base multi-crosslinked polyurethane prepared in Example 1.

[0042] Figure 2 Wide-angle X-ray diffraction spectrum of the Schiff base multi-crosslinked polyurethane prepared in Example 1.

[0043] Figure 3 Stress-strain curve of the Schiff base multi-crosslinked polyurethane prepared in Example 1.

[0044] Figure 4 Dynamic thermomechanical analysis curve of the Schiff base multi-crosslinked polyurethane prepared in Example 1.

[0045] Figure 5 Electrochemical impedance spectroscopy curve of the polyurethane-based solid-state ion conductor prepared in Example 1.

[0046] Figure 6 Stress-strain curve of the polyurethane-based solid-state ion conductor prepared in Example 1.

[0047] Figure 7 The stability graph of the flexible sensor made of the polyurethane-based solid-state ion conductor prepared in Example 1 during a 2500-second stretching cycle (strain of 100%).

[0048] Figure 8 The resistance change curves of the multimodal sensor made of the polyurethane-based solid-state ion conductor prepared in Example 1 under different conditions.

[0049] Figure 9 The structural diagram of the driving behavior sensor made of the polyurethane-based solid-state ion conductor prepared in Example 1.

[0050] Figure 10 Is Figure 9 The resistance change curves of the driving behavior sensor under different conditions. Detailed implementation mode

[0051] The technical solution of the present invention will be further described below in conjunction with the embodiments.

[0052] The chain extender used in the following embodiments is a tetrafunctional aromatic compound, including two aldehyde groups and two hydroxyl groups, and its structural formula is shown as follows:[[]]

[0053]

[0054] The chain extender in the following examples is preferably 2,5-dihydroxyterephthalaldehyde.

[0055] The structural formula of the hexamethylene diisocyanate trimer curing agent in the following examples is shown as follows:[[]]

[0056]

[0057] The following are the embodiments of the present invention:[[]]

[0058] Example 1

[0059] The preparation method of the Schiff base multi-crosslinked polyurethane of the present invention is as follows:[[]]

[0060] The main raw materials required are proportioned by weight as follows: 20 parts of polytetramethylene ether glycol, 40 parts of hexamethylene diisocyanate, 40 parts of the chain extender 2,5-dihydroxyterephthalaldehyde, 1 part of the catalyst dibutyltin dilaurate (DBTDL), 40 parts of isophthalic dihydrazide, 35 parts of hexamethylene diisocyanate trimer curing agent; 140 parts of anhydrous organic solvent N,N-dimethylacetamide (DMAC).

[0061] The preparation process is:[[]]

[0062] (1) Heat 20 parts of polytetramethylene ether glycol placed in a three-necked flask to 120 °C in a vacuum environment, keep warm and stir for 60 min, and then cool down to 80 °C;

[0063] (2) Dissolve hexamethylene diisocyanate in 20 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (1) under a nitrogen atmosphere;

[0064] (3) Add a catalyst to the three-necked flask in step (2), keep the temperature at 80 °C and react for 8 hours. Then dissolve 2,5-dihydroxyterephthalaldehyde in 40 parts of anhydrous organic solvent and add it to the three-necked flask in step (2), and keep the temperature at 90 °C and react for 12 hours;

[0065] (4) Dissolve isophthaloyl hydrazide in 50 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (3), and keep the temperature at 90 °C and stir for 12 hours;

[0066] (5) Dissolve the hexamethylene diisocyanate trimer curing agent in 30 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (4), and keep the temperature at 60 °C and stir for 14 hours to obtain the Schiff base multi-crosslinked polyurethane.

[0067] The method for using the obtained Schiff base multi-crosslinked polyurethane to prepare a polyurethane-based solid ion conductor is as follows:

[0068] The main raw materials required are in a weight ratio of: 120 parts of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 100 parts of Schiff base multi-crosslinked polyurethane;

[0069] Preparation process: Dissolve lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in anhydrous organic solvent and mix it with Schiff base multi-crosslinked polyurethane for 4 h to obtain a mixed solution. Then place the mixed solution on a hot plate at 90 °C to evaporate the solvent to obtain a polyurethane-based solid ion conductor. The anhydrous organic solvent is N,N-dimethylacetamide (DMAC), and its amount is appropriate to achieve dissolution.

[0070] Result analysis

[0071] Figure 1 It is the infrared spectrum of the Schiff base multi-crosslinked polyurethane prepared in Example 1. From Figure 1 It can be seen that the characteristic peaks of the -N=C=O group at 2260 cm -1 disappear, the characteristic peaks of the -OH group at 3400 - 3500 cm -1 disappear, the stretching vibration peak of the -C-O-C- of the polyether molecular chain is at 1090 cm -1 and the stretching vibration of -N-H- at 1535 cm-1 corresponds to the urethane bond. 1714 cm-1 The peak at [1257 cm⁻¹] is attributed to the C=O stretching vibration of the carbamate group. -1 The stretching vibration of -NH-C=N- appears at [a certain wavenumber], corresponding to the hydrazone bond formed by the aldehyde group and hydrazide in the three structures. These results prove the successful synthesis of the polyurethane.

[0072] Figure 2 It is the wide-angle X-ray diffraction spectrogram of the Schiff base multi-crosslinked polyurethane prepared in Example 1. The wide-angle XRD test results show that the Schiff base multi-crosslinked polyurethane has a typical polymer broad peak at 2θ = 20°, indicating that the polyurethane has no obvious crystallinity and is an amorphous structure.

[0073] Figure 3 It is the stress-strain curve of the Schiff base multi-crosslinked polyurethane prepared in Example 1. From Figure 3 it can be seen that the tensile strength of the Schiff base multi-crosslinked polyurethane of the present invention is about 51 MPa, and the elongation at break is about 700%, indicating that the Schiff base multi-crosslinked polyurethane has high strength and high toughness.

[0074] Figure 4 It is the dynamic thermomechanical analysis curve of the Schiff base multi-crosslinked polyurethane prepared in Example 1. From Figure 4 it can be seen that the glass transition temperature of the Schiff base multi-crosslinked polyurethane of the present invention is about -52 °C.

[0075] Figure 5 It is the electrochemical impedance spectroscopy curve of the polyurethane-based solid-state ion conductor prepared in Example 1. From Figure 5 it can be seen that the polyurethane-based solid-state ion conductor obtained in the present invention has high ionic conductivity.

[0076] Figure 6 It is the stress-strain curve of the polyurethane-based solid-state ion conductor prepared in Example 1. From Figure 6 it can be seen that the tensile strength of the polyurethane-based solid-state ion conductor obtained in the present invention is about 3.5 MPa.

[0077] Test Characterization

[0078] The mechanical property test methods of the Schiff base multi-crosslinked polyurethane and the polyurethane-based solid-state ion conductor of the present invention are as follows:

[0079] All mechanical test methods use a universal testing machine. The specimens are cut into dumbbell-shaped strips and fixed at both ends of the tensile grip distance. The initial grip distance is set to 14 mm, and the tensile rate is 50 mm / min. -1 The true stress (σ) and elongation at break (ε) are calculated according to the following formulas:

[0080] Note: In the translation, the wavenumber in [1257 cm⁻¹] and [a certain wavenumber] is left in this form because the specific value is not clear in the original text. If there is more specific information, it can be accurately translated. Also, the formulas in ,

[0080] , are not shown in the original text, so they are just left as they are in the translation.

[0081] Among them, σ is the tensile strength, F is the maximum tensile force borne when the film breaks, b is the width of the film, d is the thickness of the film, ε is the elongation at break of the composite film, Lmax is the distance between the clamps when the film breaks, and L0 is the distance between the clamps at the beginning of the composite film.

[0082] The test method for the conductivity of the polyurethane-based solid-state ion conductor of the present invention is as follows:

[0083] The ionic conductivity is tested by using a circular sample film. The circular sample film (diameter 16 mm) is clamped between two stainless steel electrodes with a diameter of 16 mm, and the impedance spectrum (EIS) is measured by an electrochemical workstation (CHI660E, Chenhua). The frequency range is set to 0.001 Hz to 1 MHz, and the amplitude is 10 mV. The ionic conductivity can be calculated by the following equation:

[0084]

[0085] L represents the thickness of the circular sample, R represents the impedance measured by EIS, and S represents the contact area between the sample film and the electrode.

[0086] Example 2

[0087] The preparation method of the Schiff base multi-crosslinked polyurethane of the present invention is as follows:

[0088] The main raw materials required are in a weight ratio of: 20 parts of polytetramethylene ether glycol, 40 parts of hexamethylene diisocyanate, 40 parts of chain extender 2,5-dihydroxyterephthaldehyde, 1 part of catalyst dibutyltin dilaurate (DBTDL), 40 parts of p-phenylenediamine, 35 parts of hexamethylene diisocyanate trimer curing agent; 120 parts of anhydrous organic solvent N,N-dimethylacetamide (DMAC).

[0089] The preparation process is:

[0090] (1) Heat 20 parts of polytetramethylene ether glycol placed in a three-necked flask to 120 °C in a vacuum environment, keep stirring for 60 min, and then cool down to 80 °C;

[0091] (2) Dissolve hexamethylene diisocyanate in 30 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (1) under a nitrogen atmosphere;

[0092] (3) Add a catalyst to the three-necked flask in step (2), keep the reaction at 80 °C for 6 hours, then dissolve 2,5-dihydroxyterephthaldehyde in 40 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (2), and keep the reaction at 80 °C for 10 hours;

[0093] (4) Dissolve p-phenylenediamine in 20 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (3), and keep stirring at 60 °C for 10 hours;

[0094] (5) Dissolve the hexamethylene diisocyanate trimer curing agent in 30 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (4), and keep stirring at 70 °C for 12 hours to obtain the Schiff base multi-crosslinked polyurethane.

[0095] The method for using the obtained Schiff base multi-crosslinked polyurethane to prepare a polyurethane-based solid ion conductor is as follows:

[0096] The main raw materials required are in a weight ratio of: 120 parts of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 100 parts of Schiff base multi-crosslinked polyurethane;

[0097] Preparation process: Dissolve lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in anhydrous organic solvent and mix it with Schiff base multi-crosslinked polyurethane for 4 h to obtain a mixed solution, and then place the mixed solution on a hot plate at 80 °C to evaporate the solvent to obtain a polyurethane-based solid ion conductor. The anhydrous organic solvent is N,N-dimethylacetamide (DMAC), and its dosage is appropriate to achieve dissolution.

[0098] Example 3

[0099] The preparation method of the Schiff base multi-crosslinked polyurethane of the present invention is as follows:

[0100] The main raw materials required are in a weight ratio of: 20 parts of polytetramethylene ether glycol, 40 parts of hexamethylene diisocyanate, 40 parts of chain extender 2,5-dihydroxyterephthaldehyde, 1 part of catalyst dibutyltin dilaurate (DBTDL), 40 parts of adipic dihydrazide, 35 parts of hexamethylene diisocyanate trimer curing agent; 120 parts of anhydrous organic solvent N,N-dimethylacetamide (DMAC).

[0101] The preparation process is:

[0102] (1) Heat 20 parts of polytetramethylene ether glycol placed in a three-necked flask to 120 °C under a vacuum environment, keep stirring for 60 min, and then cool down to 90 °C;

[0103] (2) Dissolve hexamethylene diisocyanate in 20 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (1) under a nitrogen atmosphere;

[0104] (3) Add a catalyst to the three-necked flask in step (2), keep the temperature at 80 °C for 8 hours of reaction, then dissolve 2,5-dihydroxyterephthalaldehyde in 30 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (2), and keep the temperature at 80 °C for 10 hours of reaction;

[0105] (4) Dissolve adipic dihydrazide in 40 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (3), and keep stirring at 80 °C for 12 hours;

[0106] (5) Dissolve hexamethylene diisocyanate trimer curing agent in 30 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (4), and keep stirring at 80 °C for 12 hours to obtain the Schiff base multi-crosslinked polyurethane.

[0107] The method for preparing the polyurethane-based solid ion conductor using the above-obtained Schiff base multi-crosslinked polyurethane is as follows:

[0108] The main raw materials required are in a weight ratio of: 120 parts of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 100 parts of Schiff base multi-crosslinked polyurethane;

[0109] Preparation process: Dissolve lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in anhydrous organic solvent and mix it with Schiff base multi-crosslinked polyurethane for 4 h to obtain a mixed solution, and then place the mixed solution on a hot plate at 80 °C to evaporate the solvent to obtain the polyurethane-based solid ion conductor. The anhydrous organic solvent is N,N-dimethylacetamide (DMAC), and its amount is appropriate to achieve dissolution.

[0110] Example 4

[0111] The preparation method of the Schiff base multi-crosslinked polyurethane of the present invention is as follows:

[0112] The main raw materials required are in a weight ratio of: 20 parts of polytetramethylene ether glycol, 40 parts of isophorone diisocyanate, 40 parts of chain extender 2,5-dihydroxyterephthalaldehyde, 1 part of catalyst dibutyltin dilaurate (DBTDL), 40 parts of isophthaloyl hydrazide, 35 parts of hexamethylene diisocyanate trimer curing agent; 120 parts of anhydrous organic solvent N,N-dimethylacetamide (DMAC).

[0113] The preparation process is:

[0114] (1) Under a vacuum environment, heat 20 parts of polytetramethylene ether glycol placed in a three-necked flask to 120 °C, keep stirring for 60 min, and then cool down to 80 °C;

[0115] (2) Dissolve isophorone diisocyanate in 20 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (1) under a nitrogen atmosphere;

[0116] (3) Add a catalyst to the three-necked flask in step (2), keep the temperature at 80 °C for 4 hours, then dissolve 2,5-dihydroxyterephthalaldehyde in 30 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (2), and keep the temperature at 80 °C for 10 hours;

[0117] (4) Dissolve isophthalohydrazide in 20 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (3), and keep stirring at 80 °C for 12 hours;

[0118] (5) Dissolve hexamethylene diisocyanate trimer curing agent in 30 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (4), and keep stirring at 60 °C for 12 hours to obtain a Schiff base multi-crosslinked polyurethane.

[0119] The method for using the obtained Schiff base multi-crosslinked polyurethane to prepare a polyurethane-based solid ion conductor is as follows:

[0120] The main raw materials required are in a weight ratio of: lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) 120 parts, Schiff base multi-crosslinked polyurethane 100 parts;

[0121] Preparation process: Dissolve lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in anhydrous organic solvent and mix it with Schiff base multi-crosslinked polyurethane for 4 h to obtain a mixed solution, and then place the mixed solution on a hot plate at 80 °C to evaporate the solvent to obtain a polyurethane-based solid ion conductor. The anhydrous organic solvent is N,N-dimethylacetamide (DMAC), and its amount is appropriate for dissolution.

[0122] Example 5

[0123] The preparation method of the Schiff base multi-crosslinked polyurethane of the present invention is as follows:

[0124] The main raw materials required are in a weight ratio of: polytetramethylene ether glycol 20 parts, isophorone diisocyanate 40 parts, chain extender 2,5-dihydroxyterephthalaldehyde 40 parts, catalyst dibutyltin dilaurate (DBTO) 1 part, p-phenylenediamine 40 parts, hexamethylene diisocyanate trimer curing agent 35 parts; anhydrous organic solvent N,N-dimethylformamide (DMF) 120 parts.

[0125] The preparation process is:

[0126] (1) Under a vacuum environment, heat 20 parts of polytetramethylene ether glycol placed in a three-necked flask to 120 °C, keep stirring for 60 min, and then cool down to 90 °C;

[0127] (2) Dissolve isophorone diisocyanate in 20 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (1) under a nitrogen atmosphere;

[0128] (3) Add a catalyst to the three-necked flask in step (2), keep the temperature at 80 °C and react for 6 hours. Then dissolve 2,5-dihydroxyterephthalaldehyde in 30 parts of anhydrous organic solvent, and add it to the three-necked flask in step (2), and keep the temperature at 80 °C and react for 10 hours;

[0129] (4) Dissolve p-phenylenediamine in 30 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (3), and keep the temperature at 70 °C and stir for 12 hours;

[0130] (5) Dissolve hexamethylene diisocyanate trimer curing agent in 40 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (4), and keep the temperature at 80 °C and stir for 14 hours to obtain the Schiff base multi-crosslinked polyurethane.

[0131] The method for using the obtained Schiff base multi-crosslinked polyurethane to prepare a polyurethane-based solid ion conductor is as follows:

[0132] The main raw materials required are in a weight ratio of: lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) 120 parts, Schiff base multi-crosslinked polyurethane 100 parts;

[0133] Preparation process: Dissolve lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in anhydrous organic solvent and mix it with Schiff base multi-crosslinked polyurethane for 6 h to obtain a mixed solution. Then place the mixed solution on a hot plate at 90 °C to evaporate the solvent to obtain a polyurethane-based solid ion conductor. The anhydrous organic solvent is N,N-dimethylformamide (DMF), and its amount is appropriate to achieve dissolution.

[0134] Example 6

[0135] The preparation method of the Schiff base multi-crosslinked polyurethane of the present invention is as follows:

[0136] The main raw materials required are in a weight ratio of: polytetramethylene ether glycol 20 parts, isophorone diisocyanate 40 parts, chain extender 2,5-dihydroxyterephthalaldehyde 40 parts, catalyst dibutyltin dilaurate (DBTO) 3 parts, adipic dihydrazide 40 parts, hexamethylene diisocyanate trimer curing agent 35 parts; anhydrous organic solvent N,N-dimethylformamide (DMF) 130 parts.

[0137] The preparation process is:

[0138] (1) Heat 20 parts of polytetramethylene ether glycol placed in a three-necked flask to 120 °C in a vacuum environment, keep warm and stir for 60 min, and then cool down to 90 °C;

[0139] (2) Dissolve isophorone diisocyanate in 20 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (1) under a nitrogen atmosphere;

[0140] (3) Add a catalyst to the three-necked flask in step (2), keep the temperature at 90 °C and react for 4 hours. Then dissolve 2,5-dihydroxyterephthalaldehyde in 40 parts of anhydrous organic solvent, and add it to the three-necked flask in step (2), and keep the temperature at 70 °C and react for 14 hours;

[0141] (4) Dissolve adipic dihydrazide in 40 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (3), and keep warm and stir at 80 °C for 14 hours;

[0142] (5) Dissolve hexamethylene diisocyanate trimer curing agent in 30 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (4), and keep warm and stir at 90 °C for 12 hours to obtain a high-strength and high-toughness polyurethane.

[0143] The method for using the obtained Schiff base multi-crosslinked polyurethane to prepare a polyurethane-based solid ion conductor is as follows:

[0144] The required main raw materials are in a weight ratio of: lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) 120 parts, Schiff base multi-crosslinked polyurethane 100 parts;

[0145] Preparation process: Dissolve lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in anhydrous organic solvent and mix it with Schiff base multi-crosslinked polyurethane for 6 h to obtain a mixed solution. Then place the mixed solution on a hot plate at 90 °C to evaporate the solvent to obtain a polyurethane-based solid ion conductor. The anhydrous organic solvent is N,N-dimethylformamide (DMF), and its dosage is appropriate for dissolution.

[0146] Example 7

[0147] The preparation method of the Schiff base multi-crosslinked polyurethane of the present invention is as follows:

[0148] The required main raw materials are in a weight ratio of: polytetramethylene ether glycol 20 parts, dicyclohexylmethane 4,4'-diisocyanate 40 parts, chain extender 2,5-dihydroxyterephthalaldehyde 40 parts, catalyst dibutyltin dilaurate (DBTDL) 2 parts, isophthaloyl hydrazide 40 parts, hexamethylene diisocyanate trimer curing agent 35 parts; anhydrous organic solvent N,N-dimethylformamide (DMF) 120 parts.

[0149] The preparation process is as follows:

[0150] (1) Heat 20 parts of polytetramethylene ether glycol placed in a three-necked flask to 120 °C under a vacuum environment, keep stirring for 60 min, and then cool down to 80 °C;

[0151] (2) Dissolve dicyclohexylmethane 4,4'-diisocyanate in 20 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (1) under a nitrogen atmosphere;

[0152] (3) Add a catalyst to the three-necked flask in step (2), keep the reaction at 80 °C for 4 hours, then dissolve 2,5-dihydroxyterephthalaldehyde in 30 parts of anhydrous organic solvent, and add it to the three-necked flask in step (2), and keep the reaction at 80 °C for 10 hours;

[0153] (4) Dissolve isophthaloyl hydrazide in 40 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (3), and keep stirring at 90 °C for 14 hours;

[0154] (5) Dissolve hexamethylene diisocyanate trimer curing agent in 30 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (4), and keep stirring at 90 °C for 14 hours to obtain the Schiff base multiple cross-linked polyurethane.

[0155] The method for using the obtained Schiff base multiple cross-linked polyurethane to prepare a polyurethane-based solid ion conductor is as follows:

[0156] The required main raw materials are proportioned by weight as follows: 120 parts of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 100 parts of Schiff base multiple cross-linked polyurethane;

[0157] Preparation process: Dissolve lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in anhydrous organic solvent and mix it with Schiff base multiple cross-linked polyurethane for 4 h to obtain a mixed solution, and then place the mixed solution on a hot plate at 90 °C to evaporate the solvent to obtain a polyurethane-based solid ion conductor. The anhydrous organic solvent is N,N-dimethylformamide (DMF), and its dosage is appropriate to achieve dissolution.

[0158] Example 8

[0159] The preparation method of the Schiff base multiple cross-linked polyurethane of the present invention is as follows:

[0160] The weight ratio of the main raw materials required is as follows: 30 parts of polytetramethylene ether glycol, 50 parts of dicyclohexylmethane 4,4'-diisocyanate, 50 parts of chain extender 2,5-dihydroxyterephthalaldehyde, 3 parts of catalyst dibutyltin dilaurate (DBTDL), 50 parts of p-phenylenediamine, 40 parts of hexamethylene diisocyanate trimer curing agent; 120 parts of anhydrous organic solvent N,N-dimethylformamide (DMF).

[0161] The preparation process is as follows:

[0162] (1) Heat the polytetramethylene ether glycol placed in a three-necked flask to 90 °C under a vacuum environment, keep stirring for 30 min, and then cool down to 60 °C;

[0163] (2) Dissolve dicyclohexylmethane 4,4'-diisocyanate in 20 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (1) under a nitrogen atmosphere;

[0164] (3) Add the catalyst to the three-necked flask in step (2), keep the reaction at 60 °C for 5 hours, then dissolve 2,5-dihydroxyterephthalaldehyde in 40 parts of anhydrous organic solvent, and add it to the three-necked flask in step (2), and keep the reaction at 60 °C for 10 hours;

[0165] (4) Dissolve p-phenylenediamine in 30 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (3), and keep stirring at 50 °C for 8 hours;

[0166] (5) Dissolve the hexamethylene diisocyanate trimer curing agent in 30 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (4), and keep stirring at 60 °C for 8 hours to obtain the Schiff base multi-crosslinked polyurethane.

[0167] The method for using the obtained Schiff base multi-crosslinked polyurethane to prepare a polyurethane-based solid ion conductor is as follows:

[0168] The weight ratio of the main raw materials required is as follows: 120 parts of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 100 parts of Schiff base multi-crosslinked polyurethane;

[0169] Preparation process: Dissolve lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) with an anhydrous organic solvent and mix it with the Schiff base multi-crosslinked polyurethane for 4 h to obtain a mixed solution, and then place the mixed solution on a hot plate at 90 °C to evaporate the solvent to obtain a polyurethane-based solid ion conductor. The anhydrous organic solvent is N,N-dimethylformamide (DMF), and its dosage is appropriate to achieve dissolution.

[0170] Example 9

[0171] The preparation method of the Schiff base multi-crosslinked polyurethane of the present invention is as follows:

[0172] The main raw materials required are proportioned by weight as follows: 25 parts of polytetramethylene ether glycol, 60 parts of dicyclohexylmethane 4,4'-diisocyanate, 60 parts of chain extender 2,5-dihydroxyterephthalaldehyde, 3 parts of catalyst dibutyltin dilaurate (DBTDL), 60 parts of adipic dihydrazide, 50 parts of hexamethylene diisocyanate trimer curing agent; 125 parts of anhydrous organic solvent N,N-dimethylformamide (DMF).

[0173] The preparation process is as follows:

[0174] (1) Heat the polytetramethylene ether glycol placed in a three-necked flask to 100 °C in a vacuum environment, keep stirring for 50 min, and then cool down to 70 °C;

[0175] (2) Dissolve dicyclohexylmethane 4,4'-diisocyanate in 20 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (1) under a nitrogen atmosphere;

[0176] (3) Add the catalyst to the three-necked flask in step (2), keep the reaction at 80 °C for 6 hours, then dissolve 2,5-dihydroxyterephthalaldehyde in 40 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (2), and keep the reaction at 80 °C for 12 hours;

[0177] (4) Dissolve adipic dihydrazide in 30 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (3), and keep stirring at 80 °C for 12 hours;

[0178] (5) Dissolve the hexamethylene diisocyanate trimer curing agent in 35 parts of anhydrous organic solvent, and then add it to the three-necked flask in step (4), and keep stirring at 90 °C for 10 hours to obtain the Schiff base multi-crosslinked polyurethane.

[0179] The method for using the obtained Schiff base multi-crosslinked polyurethane to prepare a polyurethane-based solid ion conductor is as follows:

[0180] The main raw materials required are proportioned by weight as follows: 120 parts of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 100 parts of Schiff base multi-crosslinked polyurethane;

[0181] Preparation process: Dissolve lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) with an anhydrous organic solvent and mix it with the Schiff base multi-crosslinked polyurethane for 6 h to obtain a mixed solution, and then place the mixed solution on a hot plate at 90 °C to evaporate the solvent to obtain a polyurethane-based solid ion conductor. The anhydrous organic solvent is N,N-dimethylformamide (DMF), and its dosage is appropriate to achieve dissolution.

[0182] Application Case

[0183] The polyurethane-based solid-state ion conductor of the present invention is used to prepare a strain sensor. During application, the polyurethane-based solid-state ion conductor of the present invention is cut into a size of 30 mm in length, 6 mm in width, and 0.4 mm in thickness, and two copper wires are wrapped at both ends with conductive tape for easy measurement. A uniaxial tension and contraction with a set speed are performed on the resistive strain sensor through a stepping machine. An LCR multimeter is used to detect the resistance change under various strains in real time.

[0184] Figure 7 It is the stability map of the flexible sensor made of the polyurethane-based solid-state ion conductor prepared in Example 1 during a 2500-second stretching cycle (strain is 100%). From Figure 7 It can be seen that the strain sensor based on the polyurethane-based solid-state ion conductor of the present invention is basically stable within 2500 s during cyclic stretching with 100% strain at a speed of 3 mm / s, demonstrating the stability of the strain sensor based on the polyurethane-based solid-state ion conductor of the present invention.

[0185] Figure 8 It is the resistance change curve of the multimodal sensor made of the polyurethane-based solid-state ion conductor prepared in Example 1 under different conditions. From Figure 8 It can be seen that the multimodal sensor based on the polyurethane-based solid-state ion conductor of the present invention has high resolution ability for mechanics and temperature.

[0186] Figure 9 It is the structural diagram of the driving behavior sensor made of the polyurethane-based solid-state ion conductor prepared in Example 1.

[0187] Figure 10 It is the resistance change curve of the driving behavior sensor made of the polyurethane-based solid-state ion conductor prepared in Example 1 under different conditions. The result of road condition recognition by the sensing component of the driving behavior sensor with the support of a neural network. From Figure 10 It can be seen that the driving behavior sensor made of the polyurethane-based solid-state ion conductor of the present invention has high resolution ability for road conditions.

[0188] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A Schiff base multi-crosslinked polyurethane, characterized in that, The structural formula of the Schiff base multi-crosslinked polyurethane is shown in Formula 1: wherein R2 = R4 or R5 or R6 R3 = R7 or R8 or R9 2. The Schiff base multi-crosslinked polyurethane according to claim 1, wherein The preparation method of the Schiff base multi-crosslinked polyurethane is as follows: The main raw materials required are in the following weight ratio: 20 - 30 parts of polytetramethylene ether glycol, 40 - 60 parts of diisocyanate, 40 - 60 parts of chain extender, 1 - 3 parts of catalyst, 40 - 60 parts of crosslinking agent, and 35 - 50 parts of hexamethylene diisocyanate trimer curing agent; The preparation process is as follows: (1) Under a vacuum environment, heat the polytetramethylene ether glycol placed in a three-necked flask to 90 - 120 °C, keep stirring for 30 - 60 min, and then cool down to 60 - 90 °C; (2) Dissolve the diisocyanate in an anhydrous organic solvent, and then add it to the three-necked flask in step (1) under a nitrogen atmosphere; (3) Add the catalyst to the three-necked flask in step (2), keep reacting at 60 - 90 °C for 4 - 8 hours, then dissolve the chain extender in an anhydrous organic solvent and add it to the three-necked flask in step (2), and keep reacting at 60 - 90 °C for 8 - 14 hours; (4) Dissolve the crosslinking agent in an anhydrous organic solvent and add it to the three-necked flask in step (3), and keep stirring at 50 - 90 °C for 8 - 14 hours; (5) Dissolve the triisocyanate curing agent in an anhydrous organic solvent and add it to the three-necked flask in step (4), and keep stirring at 60 - 90 °C for 8 - 14 hours to obtain the Schiff base multi-crosslinked polyurethane.

3. The Schiff base multi-crosslinked polyurethane according to claim 2, characterized in that, The catalyst is dibutyltin dilaurate (DBTDL) or tin dilaurate (DBTO).

4. The Schiff base multi-crosslinked polyurethane according to claim 2, characterized in that The chain extender is a tetrafunctional aromatic compound, including two aldehyde groups and two hydroxyl groups, and its structural formula is shown in Formula 2:

5. The Schiff base multi-crosslinked polyurethane according to claim 2, wherein The structural formula of the hexamethylene diisocyanate trimer curing agent is shown in Formula 3:

6. The Schiff base multi-crosslinked polyurethane according to claim 2, wherein In steps 2 - 5, the anhydrous organic solvent is N,N-dimethylacetamide (DMAC) or N,N-dimethylformamide (DMF), and the amount used is appropriate for dissolution.

7. The Schiff base multi-crosslinked polyurethane according to claim 2, characterized in that, The diisocyanate is hexamethylene diisocyanate or dicyclohexylmethane 4,4'-diisocyanate or isophorone diisocyanate.

8. The Schiff base multi-crosslinked polyurethane according to claim 2, characterized in that, The crosslinking agent is p-phenylenediamine or isophthaloyl hydrazide or adipic dihydrazide.

9. A method for preparing a polyurethane-based solid ion conductor, characterized in that , The main raw materials required are in the following weight ratio: 120 parts of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 100 parts of polyurethane; the polyurethane uses the Schiff base multi-crosslinked polyurethane described in Claims 1 to 8; The preparation process is as follows: Dissolve lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in an anhydrous organic solvent and mix it with polyurethane for 4 - 6 h to obtain a mixed solution, and then place the mixed solution on a hot plate at 80 - 90 °C to evaporate the solvent to obtain a polyurethane-based ion-conductive elastomer; the anhydrous organic solvent is N,N-dimethylacetamide (DMAC) or N,N-dimethylformamide (DMF), and the amount used is appropriate for dissolution.

10. Use of the polyurethane-based solid ion conductor obtained by the preparation method according to claim 9, characterized in that, The polyurethane-based solid ion conductor is used to fabricate the sensing components of flexible sensors or multimodal sensors or driving behavior sensors.

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