Solvent-free bio-based dual-network ionic conductive elastomer as well as preparation method and application thereof

Abstract

The invention relates to an ionic conductive elastomer material, in particular to a solvent-free bio-based dual-network ionic conductive elastomer as well as a preparation method and application thereof. The preparation method comprises the following steps: firstly, modifying 5-hydroxymethylfurfural (5-HMF) to obtain a new compound; and introducing the new compound serving as a monomer into a polymer which takes acrylate, an alcohol polymer and conductive ionic salt as monomers, thereby obtaining the solvent-free bio-based dual-network ionic conductive elastomer. The ionic conductive elastomer provided by the invention has excellent mechanical properties, the tensile strength is 0.877 MPa, and the elongation at break is 587%; the ionic conductivity is relatively high, and the ionic conductivity can reach 3.7 * 10 <-3 > S.m <-1 >; an optical transparency of about 82% to a wavelength range of 400-800 nm is provided.

Description

Technical Field

[0001] This invention relates to an ion-conductive elastomer material, and more specifically, to a solvent-free bio-based dual-network ion-conductive elastomer, its preparation method, and its application. Background Technology

[0002] In recent years, the rapid development of flexible electronic devices such as wearable electronics, electronic skin, soft robots, and human-machine interfaces has placed higher demands on the performance of conductive materials. In addition to conductivity, they also need to possess transparency, sensitivity, and excellent mechanical properties.

[0003] Ionic conductors, formed by introducing migrating ions into flexible polymer matrices (such as hydrogels and ionogels), are ideal materials for wearable electronics. However, hydrogels and ionogels suffer from drawbacks such as easy dehydration, leakage, limited conductivity, and safety hazards, which restrict their applications.

[0004] Ion-conducting elastomers are a class of soft materials that combine ion-conducting networks with polymer elastomer matrices, possessing both elastic mechanical properties and ion conductivity. Ion-conducting elastomers offer significant advantages due to their solid-state characteristics, thermal stability, and non-volatility. Therefore, as novel stretchable conductors, ion-conducting elastomers have attracted considerable attention in the field of flexible ion-electronic devices in recent years. However, achieving multifunctional all-solid-state elastomers that combine high mechanical strength and high ion conductivity remains a challenge.

[0005] 5-Hydroxymethylfurfural (5-HMF) is prepared from renewable resources such as corn, sugarcane, and lignocellulose. It possesses good chemical reactivity and, as a functional monomer precursor, can be introduced into elastomer networks to impart bio-based properties to materials while improving environmental sustainability. However, the introduction of 5-HMF suffers from insufficient reactivity and structural stability, making it difficult to obtain structurally uniform and stable elastomer networks. Summary of the Invention

[0006] To address the technical problem of poor tensile strength in ion-conducting elastomers prepared by introducing 5-hydroxymethylfurfural (5-HMF), this invention provides a solvent-free bio-based dual-network ion-conducting elastomer, its preparation method, and its application.

[0007] This invention first modifies 5-hydroxymethylfurfural (5-HMF) to obtain a new compound; then the new compound is introduced as a monomer into a polymer with acrylate, alcohol polymer and conductive ionic salt as monomers, thereby obtaining a solvent-free bio-based dual-network ionic conductive elastomer.

[0008] The purpose of this invention is to provide a new compound.

[0009] The structural formula of the compound is: The compound was named 1-acrylate-5-aminocarbonylfurfural.

[0010] The 1-acrylate-5-aminocarbonylfurfural is produced by reacting 5-hydroxymethylfurfural and 2-ethyl isocyanate acrylate.

[0011] A second objective of this invention is to provide a method for preparing the compound (1-acrylate-5-aminocarbonylfurfural) described in one of the objectives of this invention.

[0012] The method for preparing 1-acrylate-5-aminocarbonylfurfural includes: Under an inert atmosphere, 5-hydroxymethylfurfural and 2-isocyanate ethyl acrylate dissolved in a solvent are mixed with a catalyst and stirred at 60-80 °C for 8-16 h. The solvent in the reaction solution is removed and the mixture is dried to obtain the 1-acrylate-5-aminocarbonylfurfural.

[0013] The solvent can be any one or more existing solvents capable of dissolving 5-hydroxymethylfurfural and ethyl isocyanate acrylate. Preferably, the solvent is selected from at least one of dichloromethane, tetrahydrofuran, n-heptane, and trichloromethane.

[0014] The catalyst can be any one or more existing catalysts capable of catalyzing the addition reaction of isocyanate groups (-NCO) and hydroxyl groups (-OH) to form urethane bonds. As a preferred embodiment, the catalyst is selected from at least one of dibutyl dilaurate, dibutyltin dilaurate, stannous octoate, and triethylenediamine.

[0015] The solvent removal method can be a conventional method. As a preferred option, vacuum evaporation is used to remove most of the solvent.

[0016] The drying process can employ conventional drying methods. As a preferred option, vacuum drying at room temperature is used.

[0017] The drying time can be a conventional drying time. Preferably, the drying time is 24 hours or more.

[0018] The preparation method requires a very small amount of catalyst, and usually does not require a catalyst removal step.

[0019] One specific embodiment of the preparation method includes: adding dibutyltin dilaurate to 5-hydroxymethylfurfural and 2-isocyanate ethyl acrylate dissolved in dichloromethane, stirring at 70 °C under a nitrogen atmosphere for 12 h, and after the reaction is complete, the reaction solution is dark red; placing the reaction solution on a rotary evaporator, vacuum evaporating to remove most of the solvent to concentrate the reaction solution; drying the concentrated reaction solution in a vacuum oven for 48 h to obtain a brown viscous liquid. The obtained brown viscous liquid is 1-acrylate-5-aminocarbonylfurfural.

[0020] 5-Hydroxyfurfural lacks polymerizable unsaturated functional groups in its molecular structure and has insufficient UV absorption capacity. Furthermore, it preferentially undergoes photodegradation under UV light, preventing effective polymerization via conventional UV-initiated methods and resulting in polymers with no practical value under standard photopolymerization conditions. However, 1-acrylate-5-aminocarbonylfurfural, modified from 5-hydroxymethylfurfural, can be directly incorporated into ion-conducting elastomers and rapidly polymerizes under UV irradiation, yielding ion-conducting elastomers with excellent mechanical, electrical, and optical properties.

[0021] A third objective of this invention is to provide a prepolymer solution for preparing ion-conductive elastomers.

[0022] The prepolymer solution contains acrylate, 1-acrylate-5-aminocarbonylfurfural, alcohol polymer, conductive ionic salt, and photoinitiator. None of the monomers in the prepolymer solution undergo polymerization.

[0023] In the prepolymer solution, acrylates, alcohol polymers, and conductive ionic salts are conventional monomers used to construct ion-conducting elastomers, while 1-acrylate-5-aminocarbonylfurfural is a newly introduced monomer. Compared to ion-conducting elastomers constructed from acrylates, alcohol polymers, and conductive ionic salts, the tensile strength of the ion-conducting elastomer constructed from 1-acrylate-5-aminocarbonylfurfural, acrylates, alcohol polymers, and conductive ionic salts is significantly improved after the introduction of 1-acrylate-5-aminocarbonylfurfural, while the elongation at break remains essentially unchanged. Therefore, the introduction of 1-acrylate-5-aminocarbonylfurfural into the aforementioned prepolymer system for preparing ion-conducting elastomers can significantly improve the tensile strength of the ion-conducting elastomers while maintaining a substantially unchanged elongation at break.

[0024] The basic monomers used in the prepolymer solution to construct the ion-conducting elastomer are acrylate and alcohol polymers. This is because the introduction of 1-acrylate-5-aminocarbonylfurfural into any existing ion-conducting elastomer does not necessarily produce the effect of "significantly increasing the tensile strength of the ion-conducting elastomer while maintaining its elongation at break essentially unchanged."

[0025] Based on a total content of 100 wt% of acrylate, 1-acrylate-5-aminocarbonylfurfural, alcohol polymer, conductive ionic salt, and photoinitiator, the content of 1-acrylate-5-aminocarbonylfurfural in the prepolymer solution is 1-60 wt%, for example, 5 wt%, 10 wt%, 12 wt%, 15 wt%, 18 wt%, 20 wt%, 23 wt%, 25 wt%, 30 wt%, 32 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, preferably 10-50 wt%.

[0026] The amount of acrylate used can be the conventional amount. As a preferred embodiment, based on a total of 100 wt% of acrylate, 1-acrylate-5-aminocarbonylfurfural, alcohol polymer, conductive ionic salt, and photoinitiator, the acrylate content in the prepolymer solution is 10-70 wt%, for example, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, preferably 20-65 wt%.

[0027] The acrylate can be any one or more existing acrylate compounds that can be used to prepare ion-conducting elastomers. As a preferred embodiment, the acrylate is selected from at least one of hydroxyethyl acrylate, ethoxyethyl acrylate, tert-butyl methacrylate, hydroxybutyl acrylate, and butyl acrylate.

[0028] The amount of the alcohol polymer can be the conventional amount. As a preferred embodiment, based on a total of 100 wt% of acrylate, 1-acrylate-5-aminocarbonylfurfural, alcohol polymer, conductive ionic salt and photoinitiator, the content of alcohol polymer in the prepolymer solution is 10-25 wt%, for example 15 wt%, 20 wt%, 25 wt%, preferably 15-20 wt%.

[0029] The alcohol polymer can be any one or more existing alcohol polymers that can be used to prepare ion-conducting elastomers. As a preferred embodiment, the alcohol polymer is selected from at least one of polyethylene glycol, polypropylene glycol, polytetrahydrofuran glycol, and polyvinyl alcohol.

[0030] The amount of photoinitiator used can be the conventional amount. As a preferred embodiment, based on a total of 100 wt% of acrylate, 1-acrylate-5-aminocarbonylfurfural, alcohol polymer, conductive ionic salt, and photoinitiator, the content of photoinitiator in the prepolymer solution is 1-3 wt%, for example 1.5 wt%, 1.8 wt%, 2.0 wt%, preferably 1.5-2.0 wt%.

[0031] The photoinitiator can be any one or more existing photoinitiators capable of initiating the polymerization of acrylates, 1-acrylate-5-aminocarbonylfurfural, alcohol polymers, and conductive ion salts under light conditions. As a preferred embodiment, the photoinitiator is selected from at least one of benzoin dimethyl ether, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexylbenzophenone, (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, and 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone. The amount of the conductive ionic salt can be the conventional amount. As a preferred embodiment, based on a total content of 100 wt% of acrylate, 1-acrylate-5-aminocarbonylfurfural, alcohol polymer, conductive ionic salt, and photoinitiator, the content of the conductive ionic salt in the prepolymer solution is 1-30 wt%, for example, 3 wt%, 4 wt%, 5 wt%, 15 wt%, 20 wt%, 25 wt%, preferably 4-27 wt%.

[0032] The conductive ionic salt can be any one or more existing conductive ionic salts suitable for preparing ion-conducting elastomers. Preferably, the conductive ionic salt is selected from lithium salts or combinations of lithium salts and quaternary ammonium salts; more preferably, the conductive ionic salt is composed of lithium salts and quaternary ammonium salts.

[0033] The lithium salt is selected from at least one of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium chloride, lithium tetrafluoroborate, and lithium hexafluorophosphate.

[0034] The quaternary ammonium salt is selected from at least one of choline chloride, tetramethylammonium chloride, and tetraethylammonium chloride.

[0035] When the conductive ionic salt is composed of lithium salt and quaternary ammonium salt, the quaternary ammonium salt content is less than or equal to 25 wt%, for example, 0.01 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, preferably 5-20 wt%, based on a total of 100 wt% of the acrylate, 1-acrylate-5-aminocarbonylfurfural, alcohol polymer, lithium salt and photoinitiator.

[0036] The method for preparing the prepolymer solution includes mixing the components. As a specific embodiment, this includes: mixing acrylate and alcohol polymers, 1-acrylate-5-aminocarbonylfurfural and a photoinitiator at 30 °C until homogeneous; adding lithium salt and mixing until homogeneous at 40 °C; adding quaternary ammonium salt and mixing until homogeneous at 40 °C to obtain the prepolymer solution.

[0037] The fourth objective of this invention is to provide an ion-conductive elastomer.

[0038] The ion-conductive elastomer is polymerized from the prepolymer solution as described in the third objective of the invention under UV radiation.

[0039] The fifth objective of this invention is to provide a method for preparing the ion-conductive elastomer described in the fourth objective of this invention.

[0040] The preparation method includes placing the prepolymer solution described in the third objective of the invention in a mold and subjecting it to UV irradiation.

[0041] UV radiation is the exposure to ultraviolet light.

[0042] The UV radiation parameters can be the standard parameters.

[0043] As a preferred option, the wavelength of UV radiation is 320-400 nm, for example 365 nm.

[0044] As a preferred option, the UV radiation intensity is 2-8 W / cm². -2 For example, 5 mW cm -2 .

[0045] As a preferred option, the UV irradiation time is 10-40 min, for example 30 min.

[0046] As a preferred embodiment, the prepolymer solution is placed in a vacuum at 40-70 °C for 1-4 h, for example, in a vacuum at 50 °C for 2 h, before UV irradiation.

[0047] The sixth objective of this invention is to provide an application of the ion-conducting elastomer described in the fourth objective of this invention or the ion-conducting elastomer prepared by the preparation method described in the fifth objective of this invention in the field of flexible sensors.

[0048] Compared with the prior art, the beneficial effects of the present invention are as follows: The ion-conductive elastomer provided by this invention possesses excellent mechanical properties, with a tensile strength of 0.877 MPa and an elongation at break of 587%; it also exhibits high ionic conductivity, reaching 3.7 × 10⁻⁶ MPa. -3 S·m -1 It has an optical transparency of approximately 82% in the wavelength range of 400-800 nm.

[0049] The ion-conductive elastomer provided by this invention possesses high sensitivity and can be used as a strain sensor for real-time monitoring of joint movements in different parts of the human body. This sensor can operate stably even at temperatures below -20°C, enabling accurate detection of movements in various parts of the body. Furthermore, by using the sensor as a capacitive stylus, conventional touch operation functions can be achieved. In addition, the sensor can achieve Morse code encrypted transmission, providing a feasible interaction method for secure communication. Devices fabricated from bio-based dual-network ion-conductive elastomers possess both excellent mechanical and electrochemical properties, showing broad application prospects in flexible sensors and related fields.

[0050] The explanation for this likely stems primarily from stretching deformation, which causes molecular chain orientation, thereby altering the migration path length of lithium ions. Attached Figure Description

[0051] Figure 1 These are the FTIR spectra of 5-hydroxymethylfurfural, 2-isocyanoacrylate, and 1-acrylate-5-aminocarbonylfurfural; Figure 2 These are the tensile stress-strain curves of the ion-conducting elastomers prepared in Examples 2-6 and Comparative Example 1; Figure 3 The tensile recovery curve of the dual-network ionic elastomer prepared in Example 4 is shown. Figure 4 The room temperature conductivity of the ion-conducting elastomers prepared in Examples 2-6; Figure 5 These are the ultraviolet spectra of the ion-conducting elastomers prepared in Examples 2, 7, 8, 9, and 10; Figure 6 The relative resistance change of the dual-network ionic elastomer prepared in Example 4 under different strains; Figure 7 The relative resistance change of the dual-network ion elastomer sensor prepared in Example 4; Figure 8 This is a schematic diagram of Morse code transmission and the transmission of the Morse code for "can" by the dual-network ion elastomer prepared in Example 4; Figure 9 The image shows a double-network ionic elastomer prepared in Example 4 mimicking a human finger drawing on a mobile phone. Detailed Implementation

[0052] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0053] The reagents used in the following examples and comparative examples are all commercially available products.

[0054] Among them are lithium bis(trifluoromethanesulfonylimide) (LiTFSI, 99%, Maclean), hydroxyethyl acrylate (HEA, >99%, Maclean), 5-hydroxymethylfurfural (HMF, 98%, Solarbio), 2-(acryloyloxy)ethyl isocyanate (98%, Solarbio), polyethylene glycol (PEG 4000, Shanghai Aladdin Reagent), 2,2-dimethoxy-2-phenylacetophenone (photoinitiator DMPA, ≥97%, Shanghai Maclean), choline chloride (ChCl, AR, Shanghai Aladdin Reagent) and dichloromethane (CH2Cl2, >99%, Maclean).

[0055] All other reagents were purchased from Shanghai Maclean Biochemical Co., Ltd.

[0056] Example 1 Synthesize 1-acrylate-5-aminocarbonylfurfural.

[0057] Under a nitrogen atmosphere, 100 μL of DBTAL (dibutyl dilaurate) was added to HMF (5-hydroxyfurfural) (5.04 g, 40 mmol) and IAEA (2-isocyanate acrylate) (5.37 ml, 40 mmol) dissolved in CH2Cl2 (dichloromethane), and the mixture was heated to 70 °C and stirred for 12 h. After the reaction was complete, the reaction solution was dark red. Most of the dichloromethane solvent was removed using a rotary evaporator, and the concentrated reaction solution was dried in a vacuum oven for 48 hours to obtain a brown, viscous liquid product, HMF-IAEA (1-acrylate-5-aminocarbonylfurfural).

[0058] The FTIR spectra of 5-hydroxymethylfurfural (HMF), 2-isocyanate acrylate (IAEA), and 1-aminocarbonylfurfural (HMF-IAEA) are as follows: Figure 1 As shown.

[0059] Figure 1 The HMF-IAEA spectrum shows that the characteristic FT-IR absorption band of the isocyanate group (-N=C=O) at 2276 cm⁻¹ disappears, replaced by new bands corresponding to the urethane group, particularly the -NH stretching vibration at 3357 cm⁻¹ and the -C=O stretching vibration at 1729 cm⁻¹. This demonstrates the successful synthesis of 1-acrylate-5-aminocarbonylfurfural.

[0060] according to Figure 1 The structure of 1-acrylate-5-aminocarbonylfurfural can be derived as follows: .

[0061] Example 2 Weigh 12.24 g of hydroxyethyl acrylate (HEA), 5 g of polyethylene glycol (PEG4000), 6.31 g of 1-acrylate-5-aminocarbonylfurfural (HMF-IAEA), and 0.48 g of dimethyl benzoate (DMPA) into a three-necked flask containing a magnetic stir bar and mix them. Place the three-necked flask in a thermostatic magnetic stirrer and stir magnetically at 40 °C for 6 hours. Add 1.2 g of lithium bis(trifluoromethanesulfonylimide) (LiTFSI) and continue stirring at the same temperature for 30 min (until all solids are completely dissolved) to obtain a homogeneous prepolymer solution. Seal the sample with aluminum foil to prevent exposure to ambient light.

[0062] The prepolymer solution was placed in a vacuum at 50 °C for 2 hours to remove air bubbles. Subsequently, the prepolymer solution was rapidly dispensed into a polytetrafluoroethylene mold and subjected to UV irradiation (365 nm, 5 mW cm⁻¹) at room temperature. -2 The prepolymer solution in the polytetrafluoroethylene mold was cured for 30 minutes (the prepolymer solution under UV radiation undergoes a polymerization reaction); a bio-based dual-network ion-conductive elastomer with a 1-acrylate-5-aminocarbonylfurfural (HMF-IAEA) content of approximately 25 wt% was obtained.

[0063] Example 3 Weigh 13.25 g of hydroxyethyl acrylate (HEA), 5 g of polyethylene glycol (PEG4000), 7.56 g of 1-acrylate-5-aminocarbonylfurfural (HMF-IAEA), and 0.48 g of dimethyl benzoate (DMPA) into a three-necked flask equipped with a magnetic stirrer and mix them. Place the three-necked flask in a thermostatic magnetic stirrer and stir magnetically at 40 °C for 6 hours. Add 2.42 g of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and continue stirring at the same temperature for 30 min. Add 1.51 g of choline chloride (ChCl) and stir at the same temperature for 10 min (until all solids are completely dissolved) to obtain a homogeneous prepolymer solution. Seal the sample with aluminum foil to prevent exposure to ambient light.

[0064] The prepolymer solution was placed in a vacuum at 50 °C for 2 hours to remove air bubbles. Subsequently, the prepolymer solution was rapidly dispensed into a polytetrafluoroethylene mold and subjected to UV irradiation (365 nm, 5 mW cm⁻¹) at room temperature. -2 The prepolymer solution in the polytetrafluoroethylene mold was cured for 30 minutes (the prepolymer solution under UV radiation underwent a polymerization reaction); a bio-based dual-network ion-conductive elastomer with a 1-acrylate-5-aminocarbonyl furfural (HMF-IAEA) content of about 25 wt% and a choline chloride content of about 5 wt% was obtained.

[0065] Example 4 Weigh 11.84 g of hydroxyethyl acrylate (HEA), 5 g of polyethylene glycol (PEG4000), 7.56 g of 1-acrylate-5-aminocarbonylfurfural (HMF-IAEA), and 0.48 g of dimethyl benzoate (DMPA) into a three-necked flask equipped with a magnetic stirrer and mix them. Place the three-necked flask in a thermostatic magnetic stirrer and stir magnetically at 40 °C for 6 hours. Add 2.42 g of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and continue stirring at the same temperature for 30 min. Add 3.02 g of choline chloride (ChCl) and stir at the same temperature for 10 min (until all solids are completely dissolved) to obtain a homogeneous prepolymer solution. Seal the sample with aluminum foil to prevent exposure to ambient light.

[0066] The prepolymer solution was placed in a vacuum at 50 °C for 2 hours to remove air bubbles. Subsequently, the prepolymer solution was rapidly dispensed into a polytetrafluoroethylene mold and subjected to UV irradiation (365 nm, 5 mW cm⁻¹) at room temperature. -2 The prepolymer solution in the polytetrafluoroethylene mold was cured for 30 minutes (the prepolymer solution underwent a polymerization reaction under UV radiation); a bio-based dual-network ion-conductive elastomer with a 1-acrylate-5-aminocarbonyl furfural (HMF-IAEA) content of about 25 wt% and a choline chloride content of about 10 wt% was obtained.

[0067] Example 5 Weigh 10.23 g of hydroxyethyl acrylate (HEA), 5 g of polyethylene glycol (PEG4000), 7.56 g of 1-acrylate-5-aminocarbonylfurfural (HMF-IAEA), and 0.48 g of dimethyl benzoate (DMPA) into a three-necked flask equipped with a magnetic stirrer and mix them. Place the three-necked flask in a thermostatic magnetic stirrer and stir magnetically at 40 °C for 6 hours. Add 2.42 g of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and continue stirring at the same temperature for 30 min. Add 4.53 g of choline chloride (ChCl) and stir at the same temperature for 10 min (until all solids are completely dissolved) to obtain a homogeneous prepolymer solution. Seal the sample with aluminum foil to prevent exposure to ambient light.

[0068] The prepolymer solution was placed in a vacuum at 50 °C for 2 hours to remove air bubbles. Subsequently, the prepolymer solution was rapidly dispensed into a polytetrafluoroethylene mold and subjected to UV irradiation (365 nm, 5 mW cm⁻¹) at room temperature. -2 The prepolymer solution in the polytetrafluoroethylene mold was cured for 30 minutes (the prepolymer solution under UV radiation under polymerization reaction); a bio-based dual-network ion-conductive elastomer with a 1-acrylate-5-aminocarbonyl furfural (HMF-IAEA) content of about 25 wt% and a choline chloride content of about 15 wt% was obtained.

[0069] Example 6 Weigh 8.72 g of hydroxyethyl acrylate (HEA), 5 g of polyethylene glycol (PEG4000), 7.56 g of 1-acrylate-5-aminocarbonylfurfural (HMF-IAEA), and 0.48 g of dimethyl benzoate (DMPA) into a three-necked flask equipped with a magnetic stirrer and mix them. Place the three-necked flask in a thermostatic magnetic stirrer and stir magnetically at 40 °C for 6 hours. Add 2.42 g of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and continue stirring at the same temperature for 30 min. Add 6.04 g of choline chloride (ChCl) and stir at the same temperature for 10 min (until all solids are completely dissolved) to obtain a homogeneous prepolymer solution. Seal the sample with aluminum foil to prevent exposure to ambient light.

[0070] The prepolymer solution was placed in a vacuum at 50 °C for 2 hours to remove air bubbles. Subsequently, the prepolymer solution was rapidly dispensed into a polytetrafluoroethylene mold and subjected to UV irradiation (365 nm, 5 mW cm⁻¹) at room temperature. -2 The prepolymer solution in the polytetrafluoroethylene mold was cured for 30 minutes (the prepolymer solution under UV radiation underwent a polymerization reaction); a bio-based dual-network ion-conductive elastomer with a 1-acrylate-5-aminocarbonylfurfural (HMF-IAEA) content of about 25 wt% and a choline chloride content of about 20 wt% was obtained.

[0071] Example 7 Weigh 5.93 g of hydroxyethyl acrylate (HEA), 5 g of polyethylene glycol (PEG4000), 12.61 g of 1-acrylate-5-aminocarbonylfurfural (HMF-IAEA), and 0.48 g of dimethyl benzoate (DMPA) into a three-necked flask containing a magnetic stir bar and mix them. Place the three-necked flask in a thermostatic magnetic stirrer and stir magnetically at 40 °C for 6 hours. Add 1.2 g of lithium bis(trifluoromethanesulfonylimide) (LiTFSI) and continue stirring at the same temperature for 30 min (until all solids are completely dissolved) to obtain a homogeneous prepolymer solution. Seal the sample with aluminum foil to prevent exposure to ambient light.

[0072] The prepolymer solution was placed in a vacuum at 50 °C for 2 hours to remove air bubbles. Subsequently, the prepolymer solution was rapidly dispensed into a polytetrafluoroethylene mold and subjected to UV irradiation (365 nm, 5 mW cm⁻¹) at room temperature. -2 The prepolymer solution in the polytetrafluoroethylene mold was cured for 30 minutes (the prepolymer solution under UV radiation undergoes a polymerization reaction); a bio-based dual-network ion-conductive elastomer with a 1-acrylate-5-aminocarbonylfurfural (HMF-IAEA) content of approximately 50 wt% was obtained.

[0073] Example 8 Weigh 9.71 g of hydroxyethyl acrylate (HEA), 5 g of polyethylene glycol (PEG4000), 8.83 g of 1-acrylate-5-aminocarbonylfurfural (HMF-IAEA), and 0.48 g of dimethyl benzoate (DMPA) into a three-necked flask containing a magnetic stir bar and mix them. Place the three-necked flask in a thermostatic magnetic stirrer and stir magnetically at 40 °C for 6 hours. Add 1.2 g of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and continue stirring at the same temperature for 30 min (until all solids are completely dissolved) to obtain a homogeneous prepolymer solution. Seal the sample with aluminum foil to prevent exposure to ambient light.

[0074] The prepolymer solution was placed in a vacuum at 50 °C for 2 hours to remove air bubbles. Subsequently, the prepolymer solution was rapidly dispensed into a polytetrafluoroethylene mold and subjected to UV irradiation (365 nm, 5 mW cm⁻¹) at room temperature. -2 The prepolymer solution in the polytetrafluoroethylene mold was cured for 30 minutes (the prepolymer solution underwent a polymerization reaction under UV radiation); a bio-based dual-network ion-conductive elastomer with a 1-acrylate-5-aminocarbonylfurfural (HMF-IAEA) content of approximately 35 wt% was obtained.

[0075] Example 9 Weigh 14.75 g of hydroxyethyl acrylate (HEA), 5 g of polyethylene glycol (PEG4000), 3.79 g of 1-acrylate-5-aminocarbonylfurfural (HMF-IAEA), and 0.48 g of dimethyl benzoate (DMPA) into a three-necked flask containing a magnetic stir bar and mix them. Place the three-necked flask in a thermostatic magnetic stirrer and stir magnetically at 40 °C for 6 hours. Add 1.2 g of lithium bis(trifluoromethanesulfonylimide) (LiTFSI) and continue stirring at the same temperature for 30 min (until all solids are completely dissolved) to obtain a homogeneous prepolymer solution. Seal the sample with aluminum foil to prevent exposure to ambient light.

[0076] The prepolymer solution was placed in a vacuum at 50 °C for 2 hours to remove air bubbles. Subsequently, the prepolymer solution was rapidly dispensed into a polytetrafluoroethylene mold and subjected to UV irradiation (365 nm, 5 mW cm⁻¹) at room temperature. -2 The prepolymer solution in the polytetrafluoroethylene mold was cured for 30 minutes (the prepolymer solution under UV radiation undergoes a polymerization reaction); a bio-based dual-network ion-conductive elastomer with a 1-acrylate-5-aminocarbonylfurfural (HMF-IAEA) content of approximately 15 wt% was obtained.

[0077] Example 10 Weigh 16.02 g of hydroxyethyl acrylate (HEA), 5 g of polyethylene glycol (PEG4000), 2.52 g of 1-acrylate-5-aminocarbonylfurfural (HMF-IAEA), and 0.48 g of dimethyl benzoate (DMPA) into a three-necked flask containing a magnetic stir bar and mix them. Place the three-necked flask in a thermostatic magnetic stirrer and stir magnetically at 40 °C for 6 hours. Add 1.2 g of lithium bis(trifluoromethanesulfonylimide) (LiTFSI) and continue stirring at the same temperature for 30 min (until all solids are completely dissolved) to obtain a homogeneous prepolymer solution. Seal the sample with aluminum foil to prevent exposure to ambient light.

[0078] The prepolymer solution was placed in a vacuum at 50 °C for 2 hours to remove air bubbles. Subsequently, the prepolymer solution was rapidly dispensed into a polytetrafluoroethylene mold and subjected to UV irradiation (365 nm, 5 mW cm⁻¹) at room temperature. -2 The prepolymer solution in the polytetrafluoroethylene mold was cured for 30 minutes (the prepolymer solution under UV radiation undergoes a polymerization reaction); a bio-based dual-network ion-conductive elastomer with a 1-acrylate-5-aminocarbonylfurfural (HMF-IAEA) content of approximately 10 wt% was obtained.

[0079] Comparative Example 1 Weigh 12.24 g of hydroxyethyl acrylate (HEA), 5 g of polyethylene glycol (PEG4000), and 0.48 g of dimethyl benzoate (DMPA) into a three-necked flask containing a magnetic stir bar and mix them. Place the three-necked flask in a thermostatic magnetic stirrer and stir magnetically at 40 °C for 6 hours. Add 1.2 g of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and continue stirring at the same temperature for 30 min (until all solids are completely dissolved) to obtain a homogeneous prepolymer solution. Seal the sample with aluminum foil to prevent exposure to ambient light.

[0080] The prepolymer solution was placed in a vacuum at 50 °C for 2 hours to remove air bubbles. Subsequently, the prepolymer solution was rapidly dispensed into a polytetrafluoroethylene mold and subjected to UV irradiation (365 nm, 5 mW cm⁻¹) at room temperature. -2 The prepolymer solution in the polytetrafluoroethylene mold is cured for 30 minutes (the prepolymer solution undergoes a polymerization reaction under UV radiation); an ion-conductive elastomer free of 1-acrylate-5-aminocarbonylfurfural is obtained.

[0081] Comparing Example 2 and Comparative Example 1, it can be concluded that the introduction of 1-acrylate-5-aminocarbonylfurfural enhances the rigidity and mechanical strength of the network. The HMF-IAEA molecule contains a furan ring and an aminocarbonyl structure, which serve as the first rigid network and interpenetrate with the flexible PEG network to form a dual network structure.

[0082] Comparative Example 2 Weigh 12.24 g of methyl acrylate monomer, 5 g of polyvinylpyrrolidone, 6.31 g of 1-acrylate-5-aminocarbonylfurfural (HMF-IAEA), and 0.48 g of dimethyl benzoate (DMPA) into a three-necked flask containing a magnetic stir bar and mix them. Place the three-necked flask in a thermostatic magnetic stirrer and stir magnetically at 40 °C for 6 hours. Add 1.2 g of lithium bis(trifluoromethanesulfonylimide) (LiTFSI) and continue stirring at the same temperature for 30 min (until all solids are completely dissolved) to obtain a homogeneous prepolymer solution. Seal the sample with aluminum foil to prevent exposure to ambient light.

[0083] The prepolymer solution was placed in a vacuum at 50 °C for 2 hours to remove air bubbles. Subsequently, the prepolymer solution was rapidly dispensed into a polytetrafluoroethylene mold and subjected to UV irradiation (365 nm, 5 mW cm⁻¹) at room temperature. -2 The prepolymer solution in the polytetrafluoroethylene mold was cured for 30 minutes (the prepolymer solution underwent polymerization under UV radiation); the polymerization reaction of the two monomers still exhibited low conversion rate and slow reaction rate. Without the aid of specialized tools, the polymer product could easily break under slight manual force, completely lacking the mechanical load-bearing capacity and structural stability required for practical applications, and failing to meet the basic requirements for material mechanical properties during subsequent processing, assembly, or use.

[0084] Performance testing (a) Tensile property testing According to GB / T528-92, the ion-conductive elastomers prepared in Examples 2-6 and Comparative Examples 1-3 were made into strips using a type 2 dumbbell-shaped specimen cutter. The strips were then stretched at room temperature using an electronic universal tensile testing machine at a tensile speed of 50 mm·min. -1 The tensile properties of the spline were tested. The test results are as follows: Figure 2 As shown.

[0085] Figure 2 a represents the tensile stress-strain curves of Example 2 and Comparative Example 1.

[0086] Comparing the curves of Comparative Example 1 and Example 2, it can be concluded that the introduction of 1-acrylate-5-aminocarbonylfurfural can enhance the rigidity and mechanical strength of the ion-conducting elastomer network.

[0087] Figure 2 b represents the tensile stress-strain curves of Examples 2-6. Figure 2 In b, 0wt%, 5wt%, 10wt%, 15wt%, and 20wt% refer to the choline chloride content in the ion-conducting elastomer. Correspondingly, Examples 2, 3, 4, 5, and 6.

[0088] from Figure 2As can be seen from b, the mechanical properties of the surface initially improve with the increase of choline chloride content, and then gradually deteriorate.

[0089] (ii) Fatigue resistance test According to GB / T528-92, the double-network ionic elastomer prepared in Example 4 was made into strips using a type 2 dumbbell-shaped specimen cutter. The strips were then stretched at a tensile speed of 50 mm / min using an electronic universal tensile testing machine at room temperature. -1 The cyclic tensile properties of the spline were tested. The test results are as follows: Figure 3 As shown.

[0090] like Figure 3 As shown, the reversibility was evaluated by cyclic tensile loading-unloading tests conducted in the strain range of 100% to 500%, demonstrating excellent fatigue resistance.

[0091] (III) Room temperature ionic conductivity test The impedance of the ion-conducting elastomers prepared in Examples 2-6 was tested using an electrochemical workstation. The resistance R was obtained from the electrochemical impedance spectroscopy.

[0092] The formula for calculating ionic conductivity is σ = L / (R × A). In this formula, σ represents the room temperature conductivity, measured in S·cm. -1 L and A represent the thickness and cross-sectional area, respectively, in cm and cm². 2 R represents resistance, measured in Ω.

[0093] The room temperature ionic conductivity of the ion-conducting elastomers prepared in Examples 2-6 is as follows: Figure 4 As shown.

[0094] As the ChCl content increases, the ionic conductivity increases. When the ammonium chloride (ChCl) content is 15 wt%, the peak conductivity of the ionic conductive elastomer reaches 3.74 × 10⁻⁶. -3 S / m.

[0095] (iv) Transparency test The transmittance of the ion-conductive elastomers prepared in Examples 2, 7, 8, 9, and 10 was measured using a UV-Vis spectrophotometer, with air as a reference. Figure 5 As shown, the ion-conductive elastomers prepared in Examples 2, 7, 8, 9, and 10 exhibit excellent optical transparency in the visible spectrum, with a transmittance of 76-82%, reaching a peak transmittance of 82%.

[0096] Figure 5In the figures, 10wt%, 15wt%, 25wt%, 35wt%, and 50wt% refer to the content of 1-acrylate-5-aminocarbonylfurfural (HMF-IAEA), corresponding to Examples 10, 9, 2, 8, and 7.

[0097] (v) Strain sensitivity test The strain sensitivity of ion-conductive elastomers was tested using a digital multimeter and a tensile testing machine.

[0098] The ion-conductive elastomer prepared in Example 4 was fabricated into a long strip. Conductive tape was wrapped around both ends of the strip and connected to a multimeter. The strip was then clamped in a tensile testing machine fixture, and its cyclic strain response under different strains was tested. The results are as follows: Figure 6 As shown.

[0099] Figure 6 The results show that the response time of the ion-conductive elastomer is less than 20 s in three cycles with different strains. This indicates that the ion-conductive elastomer has good sensitivity and maintains good sensitivity under different strains.

[0100] (vi) Strain sensing test The ion-conductive elastomer prepared in Example 4 was fabricated into a long strip. The strip was connected to the signal transmission line of a digital multimeter and fixed to the index finger of the test subject. The real-time resistance change of the strip during joint movement was recorded. Figure 7 As can be seen, when the spline is fixed on the finger joint, it can successfully detect the signals generated in various bending movements and stabilize the signal output.

[0101] (vii) Morse code transmission information test The ion-conductive elastomer prepared in Example 4 was fixed to a finger using insulating electrical tape and connected to the signal transmission line of a digital multimeter.

[0102] In this system, a flat finger serves as the reference position: bending the finger to a 90° angle and returning it to the reference position represents a "dot," while bending the finger to a 90° angle, holding it for 1-5 seconds, and then returning it to the reference position represents a "stroke." From Figure 8 One interesting finding is that the system is adept at conveying specific information, such as the letter "can". (eight) One end of a pencil, coated with the ion-conductive elastomer prepared in Example 4, was placed in contact with a mobile phone screen, successfully drawing on the screen. Figure 9 As shown, the BUCT pattern was successfully drawn. This demonstrates that the ion-conductive elastomer prepared in this invention can replace the human body to achieve contact and operation of electronic screens.

Claims

1. A compound with the following structural formula: .

2. The compound according to claim 1, characterized in that, It is produced by reacting 5-hydroxymethylfurfural and 2-ethyl isocyanate acrylate.

3. A method for preparing the compound according to any one of claims 1-2, comprising: Under an inert atmosphere, 5-hydroxymethylfurfural and ethyl isocyanate acrylate dissolved in a solvent are mixed with a catalyst and reacted at 60-80 °C with stirring for 10-12 h. The solvent in the reaction solution is removed, and the mixture is dried to obtain the 1-acrylate-5-aminocarbonylfurfural; preferably, The solvent is selected from at least one of dichloromethane, tetrahydrofuran, n-heptane, and trichloromethane; or / and, The catalyst is selected from at least one of dibutyl dilaurate, dibutyltin dilaurate, stannous octoate, and triethylenediamine.

4. A prepolymer solution comprising acrylate, 1-acrylate-5-aminocarbonylfurfural, an alcohol polymer, a conductive ionic salt, and a photoinitiator; The 1-acrylate-5-aminocarbonylfurfural is the compound described in any one of claims 1-2 or the compound prepared by the method described in claim 3.

5. The prepolymer solution as described in claim 4, characterized in that, Based on a total of 100 wt% of acrylate, 1-acrylate-5-aminocarbonylfurfural, alcohol polymer, conductive ionic salt, and photoinitiator: The content of the 1-acrylate-5-aminocarbonylfurfural is 1-60 wt%, preferably 10-50 wt%; or / and, The acrylate content is 10-70 wt%, preferably 20-65 wt%; or / and, The content of the alcohol polymer is 10-25 wt%, preferably 15-20 wt%; or / and, The content of the conductive ionic salt is 1-30 wt%, preferably 4-27 wt%; or / and, The content of the photoinitiator is 1-3 wt%, preferably 1.5-2.0 wt%.

6. The prepolymer solution as described in claim 4, characterized in that, The acrylate is selected from at least one of hydroxyethyl acrylate, ethoxyethyl acrylate, tert-butyl methacrylate, hydroxybutyl acrylate, and butyl acrylate; or / and, The alcohol polymer is selected from at least one of polyethylene glycol, polypropylene glycol, polytetrahydrofuran glycol, and polyvinyl alcohol; or / and, The photoinitiator is selected from at least one of benzoin dimethyl ether, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexylbenzophenone, (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, and 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone; or / and, The conductive ionic salt is selected from lithium salts or combinations of lithium salts and quaternary ammonium salts; preferably, The lithium salt is selected from at least one of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium chloride, lithium tetrafluoroborate, and lithium hexafluorophosphate; or / and, The quaternary ammonium salt is selected from at least one of choline chloride, tetramethylammonium chloride, and tetraethylammonium chloride; or / and, Based on a total content of 100 wt% of the acrylate, 1-acrylate-5-aminocarbonylfurfural, alcohol polymer, lithium salt and photoinitiator, the quaternary ammonium salt content is less than or equal to 25 wt%, preferably 5-20 wt%.

7. An ion-conductive elastomer, polymerized from a prepolymer solution as described in any one of claims 4-6 under UV radiation.

8. A method for preparing the ion-conducting elastomer as described in claim 7, comprising: The prepolymer solution is placed in a mold and subjected to UV irradiation.

9. The preparation method according to claim 8, characterized in that: UV radiation has a wavelength of 320-400 nm; or / and, UV radiation intensity is 2-8 mW / cm² -2 ; or / and, UV radiation duration 10-40 min; or / and, The prepolymer solution is placed in a vacuum at 40-70 °C for 1-4 h before UV irradiation.

10. The application of an ion-conducting elastomer as described in claim 7 or an ion-conducting elastomer prepared by the preparation method as described in claim 8 or 9 in the field of flexible sensors.

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