Organosilicon supramolecular elastomer based on crown ether host-guest interaction crosslinking and preparation method thereof

Abstract

The invention relates to a preparation method of a high-stretchability organosilicon supramolecular elastomer, which comprises the following steps of: forming a pseudorotaxane structure by aldehyde group modified crown ether and secondary ammonium salt through subject-guest interaction, and introducing the pseudorotaxane structure into a polydimethylsiloxane prepolymer to obtain the high-stretchability organosilicon supramolecular elastomer. The invention provides the crown ether supramolecular polymer network which is excellent in performance, easy to synthesize and mild in synthesis condition, and the host-guest interaction of crown ether and secondary ammonium salt enables the supramolecular polymer network to have good dynamic property. And when being used as a toughening agent to be added into the organic silicon elastomer, the organic silicon elastomer has better mechanical property and energy dissipation, and the maximum elongation and ductility of the organic silicon elastomer are greatly enhanced under the condition that the mechanical strength is not sacrificed.

Description

Technical Field

[0001] This invention belongs to the field of supramolecular materials technology, and relates to an organosilicon supramolecular elastomer based on crown ether host-guest interaction crosslinking, its preparation method, and its application. Background Technology

[0002] Polysiloxane elastomers are high-molecular polymers with repeating silicon-oxygen bonds in their main chain. These materials possess excellent resistance to high and low temperatures, biocompatibility, chemical stability, and electrical insulation, making them irreplaceable in fields such as flexible electronics, biomedical devices, and soft robotics.

[0003] Stanford University's Zhenan Bao research group prepared a tensile-resistant elastomer material based on hydrogen bonds of varying strengths. By introducing two isocyanates into the PDMS system, the material achieved an elongation at break of 1200%. Fauvre et al. synthesized a self-healing silicone elastomer containing self-associative diamide groups through the Aza-Michael addition reaction of N,N'-methylenebisacrylamide with low molecular weight end-group (3-aminopropyl) polydimethylsiloxane. Gao et al. prepared a self-healing, recyclable, and robust elastomer based on the dynamic deca-hydrogen bond structure of hydrazine esters and combined with soft polydimethylsiloxane (PDMS) chains.

[0004] However, silicone elastomers still face the challenge of balancing strength and toughness, resulting in materials that typically exhibit low toughness, poor mechanical properties, and are unrepairable. These shortcomings severely limit their development in advanced applications requiring long lifespan, sustainability, or dynamic adaptability. Summary of the Invention

[0005] This invention addresses the problems of low elongation at break of traditional covalently cross-linked silicone elastomers and poor mechanical properties of silicone elastomers with single non-covalent cross-links by proposing a novel high-strength silicone supramolecular elastomer and its preparation method.

[0006] To achieve the above objectives, the present invention is implemented using the following technical solution: A method for preparing a highly stretchable organosilicon supramolecular elastomer involves forming a quasi-rotaxane structure by reacting an aldehyde-modified crown ether with a secondary ammonium salt through a host-guest interaction, and then incorporating the quasi-rotaxane structure into a polydimethylsiloxane prepolymer.

[0007] The preparation method of the above-mentioned highly tensile organosilicon supramolecular elastomer includes the following steps: (1) The aldehyde-modified benzo-24-crown-8 and the aldehyde-modified secondary ammonium salt were dispersed in tetrahydrofuran, mixed and sonicated to obtain quasi-rotaxane.

[0008] (2) Prepare the elastomer using any of the following methods: Method 1: Quasi-rotaxane was added to a tetrahydrofuran dispersion of aminopropyl-terminated polydimethylsiloxane to obtain mixture A. A tetrahydrofuran dispersion of 5'-(4-formylphenyl)-2',4',6'-trimethyl-[1,1':3',1''-terphenyl]-4,4''-dicarboxaldehyde (FTTD) was slowly added to mixture A. Under inert gas protection, the mixture was stirred evenly and reacted. After the reaction was completed, the mixture was defoamed, poured into a mold, and dried to obtain polysiloxane elastomer A.

[0009] Method 2: Quasi-rotaxane was added to a tetrahydrofuran dispersion of aminopropyl-terminated polydimethylsiloxane. After mixing evenly, a tetrahydrofuran dispersion of isophorone diisocyanate was added. After reaction, reaction solution B was obtained. A tetrahydrofuran dispersion of 5'-(4-formylphenyl)-2',4',6'-trimethyl-[1,1':3',1''-terphenyl]-4,4''-dicarboxaldehyde was slowly added to reaction solution B. Under inert gas protection, the mixture was mixed evenly and then reacted. After the reaction was completed, the mixture was defoamed, poured into a mold, and dried to obtain polysiloxane elastomer B.

[0010] Method 3: Quasi-rotaxane was added to a tetrahydrofuran dispersion of aminopropyl-terminated polydimethylsiloxane. After mixing thoroughly, a tetrahydrofuran dispersion of isophorone diisocyanate was added. After reacting overnight, reaction solution C was obtained. Tetrahydrofuran dispersions of dithiodiphenylamine and 5'-(4-formylphenyl)-2',4',6'-trimethyl-[1,1':3',1''-terphenyl]-4,4''-dicarboxaldehyde (FTTD) were slowly added to reaction solution C. Under inert gas protection, the mixture was thoroughly mixed and reacted. After the reaction was completed, the mixture was defoamed, poured into a mold, and dried to obtain polysiloxane elastomer C.

[0011] Preferably, in step (1), the molar ratio of benzo-24-crown-8 and the aldehyde-modified secondary ammonium salt is 1:1.

[0012] As a further preferred embodiment, benzo-24-crown-8 comprises two structures, denoted as R1 and R2, wherein the structural formula of R1 is as follows: .

[0013] The structure of R2 is as follows: .

[0014] There are two types of aldehyde-modified secondary ammonium salts, denoted as L1 and L2, where the structural formula of L1 is as follows: .

[0015] The L2 structure is as follows: .

[0016] As a preferred embodiment, in step (2) of method one, the molecular weight of the aminopropyl-terminated polydimethylsiloxane is 3000-20000; the molar ratio of the aminopropyl-terminated polydimethylsiloxane to 5'-(4-formylphenyl)-2',4',6'-trimethyl-[1,1':3',1''-terphenyl]-4,4''-dicarboxaldehyde and quasi-rotaxane is 150:(99-80):(1-20).

[0017] As a preferred embodiment, in step (2) Method 2, the molecular weight of the aminopropyl-terminated polydimethylsiloxane is 3000-20000; the molar ratio of aminopropyl-terminated polydimethylsiloxane, isophorone diisocyanate, 5'-(4-formylphenyl)-2',4',6'-trimethyl-[1,1':3',1''-terphenyl]-4,4''-dicarboxaldehyde (FTTD) and quasi-rotaxane is 300:150:(99-90):(1-10).

[0018] As a preferred embodiment, in step (2) of method three, the molecular weight of the aminopropyl-terminated polydimethylsiloxane is 3000-20000; the molar ratio of aminopropyl-terminated polydimethylsiloxane, dithiodiphenylamine, isophorone diisocyanate, 5'-(4-formylphenyl)-2',4',6'-trimethyl-[1,1':3',1''-terphenyl]-4,4''-dicarboxaldehyde (FTTD), and quasi-rotaxane is (297-270):(3-30):150:(99-90):(1-10).

[0019] As a preferred option, dibutyltin dilaurate is used as a catalyst in step (2) of the reaction process.

[0020] This invention proposes the organosilicon supramolecular elastomer prepared by the above method and its application as a toughening agent.

[0021] This invention utilizes aldehyde-modified crown ether supramolecular polymer networks as additives, working synergistically with hydrogen and disulfide bonds to construct high-performance organosilicon supramolecular elastomers. Compared to traditional organosilicon elastomers, the mechanical properties and energy dissipation are significantly improved. The addition of crown ether and secondary ammonium salt supramolecular polymer networks can significantly enhance the toughness and tensile properties of the original elastomer, while promoting maximum elongation and extensibility without sacrificing polymer mechanical strength.

[0022] Compared with the prior art, the advantages and positive effects of the present invention are as follows: This invention provides a high-performance, easily synthesized, and mildly synthesized crown ether supramolecular polymer network. The host-guest interaction between the crown ether and the secondary ammonium salt gives the supramolecular polymer network excellent dynamics. When added as a toughening agent to organosilicon elastomers, it improves the elastomer's mechanical properties and energy dissipation, significantly enhancing its maximum elongation and ductility without sacrificing mechanical strength. Attached Figure Description

[0023] Figure 1 The tensile stress-strain diagrams are shown for the silicone elastomer A prepared in Example 1 and the blank group.

[0024] Figure 2 The tensile stress-strain diagrams are shown for the silicone elastomer B prepared in Example 2 and the blank group.

[0025] Figure 3 The tensile stress-strain diagram is shown for the organosilicon elastomer C prepared in Example 3.

[0026] Figure 4 The image shows the cyclic tensile stress-strain diagram of the organosilicon elastomer C prepared in Example 3. Detailed Implementation

[0027] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described below with reference to specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0028] Numerous specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways than those described herein, and therefore the invention is not limited to the specific embodiments disclosed in the following specification. Example 1

[0029] (1) First, aldehyde-modified benzo-24-crown-8 (R1) was synthesized: Add 79.89 g of triethylene glycol (CAS No.: 112-27-6) to a 500 mL round-bottom flask. Dissolve 7.2 g of NaOH powder in 20 mL of deionized water and add it to the round-bottom flask. Then add 100 mL of tetrahydrofuran (THF), stir manually with a glass rod for 2 min until well mixed, and pre-cool in an ice bath at 0 °C. Add 9.53 g of p-toluenesulfonyl chloride (CAS No.: 98-59-9) to 50 mL of THF, stir with a glass rod for 2 min, and then slowly add it dropwise to the round-bottom flask using a constant pressure dropping funnel (dropping time 5 min in this example). After the addition is complete, remove the ice bath and continue the reaction at room temperature for 2 h. After the reaction is complete, add 5 drops of 1 mol·L⁻¹ solution. -1The reaction was quenched with hydrochloric acid solution. The reaction solution was evaporated at 55°C for 20 min to remove the solvent. It was then extracted three times with CH₂Cl₂ and saturated NaCl solution, 20 mL each time, to extract the organic phase. 3 g of anhydrous sodium sulfate was added, and the mixture was dried and filtered. After removing the remaining solvent by rotary evaporation at 40°C for 15 min, the crude product was purified by column chromatography (eluent: dichloromethane:ethyl acetate = 1:2, v / v) to obtain a transparent oily substance, designated R1-1 (13.2 g). Its NMR data are as follows: 1 H NMR (400 MHz, Chloroform- d ) δ 7.80 (d, J = 8.4 Hz, 1H), 7.34 (d, J = 8.0 Hz, 1H), 4.21 – 4.14 (m, 1H), 3.76 – 3.49 (m, 5H), 2.44 (s, 1H).

[0030] 1.09 g of 3,4-dihydroxybenzaldehyde (CAS No.: 139-85-5) and 5.45 g of K2CO3 were added to a 250 mL three-necked flask. After sealing, the flask was evacuated and nitrogen gas was purged three times to remove air. 6 g of compound R1-1 was added to 30 mL of acetone and injected into the flask using a syringe under a nitrogen atmosphere (normal pressure). The reaction system was heated to 70 °C in a water bath and refluxed for 48 h. After the reaction was completed, the mixture was allowed to cool naturally to room temperature. The residue was removed by suction filtration using a Buchner funnel. The filtrate was evaporated to dryness at 55 °C using a rotary evaporator to remove the solvent. The product was extracted three times with CH2Cl2 and saturated NaCl solution. The extracted organic phase was dried over anhydrous sodium sulfate and filtered. After removing the remaining solvent by rotary evaporation at 40℃ (the steps of rotary evaporation, extraction, drying, filtration, and solvent removal are consistent with the preparation process of R1-1 unless otherwise specified), the crude product was purified by column chromatography (eluent: dichloromethane: ethyl acetate: methanol = 2:2:1, v / v / v) to obtain a white powder, denoted as R1-2 (3.17 g). Its NMR data are as follows: 1 H NMR (400 MHz, Chloroform- d ) δ 9.84 (s, 1H), 7.44 (tt, J = 6.5, 3.3 Hz, 2H), 6.99 (d, J = 8.1 Hz, 1H), 4.29– 4.21 (m, 4H), 3.92 – 3.02 (m, J = 4.3 Hz, 20H).

[0031] Add 1.57 g of solid NaOH to a 250 mL three-necked flask, seal, and evacuate under nitrogen three times. Add 3.16 g of compound R1-2 to 30 mL of THF using a syringe under a nitrogen atmosphere (normal pressure). Pre-cool the flask in an ice bath at 0 °C. Add 6 g of p-toluenesulfonyl chloride to 30 mL of THF and stir manually with a glass rod for 2 min. Slowly add the solution dropwise to the three-necked flask in an ice bath at 0 °C using a syringe. After the addition is complete, maintain the reaction at 0 °C for 2 h, then allow it to react at room temperature for another 24 h. After the reaction is complete, add 5 drops of 1 mol·L⁻¹ solution. -1 The reaction was quenched with hydrochloric acid solution. The filtrate was evaporated to dryness using a rotary evaporator. The product was extracted three times with ethyl acetate and saturated NaCl solution, 20 mL each time. The extracted organic phase was dried over anhydrous sodium sulfate and filtered. After removing the remaining solvent by rotary evaporation at 40 °C (unless otherwise specified, the steps of rotary evaporation, extraction, drying, filtration, and solvent removal are consistent with the preparation process of R1-1 above), the crude product was purified by column chromatography (eluent: petroleum ether: ethyl acetate = 1:4.5, v / v). A white solid was obtained, designated as R1-3 (3.99 g). Its NMR data are as follows: 1 H NMR (400 MHz, Chloroform- d ) δ 9.83 (s, 1H), 7.81 – 7.75 (m, 4H), 7.48 – 7.39 (m, 2H), 7.32(d, J = 8.1 Hz, 4H), 6.99 (d, J = 8.2 Hz, 1H), 4.23 (dd, J = 5.7, 4.2 Hz, 2H), 4.17– 4.07 (m, 6H), 3.93 – 3.82 (m, 4H), 3.72 – 3.61 (m, 12H), 2.43 (s, 6H).

[0032] 3g of compound R1-3, 2.3g of K2CO3 powder, and 1.54g of KPF6 (CAS No.: 17084-13-8) were added to a 250mL pre-dried three-necked flask. The flask was sealed and evacuated under nitrogen three times. 0.58g of 3,4-dihydroxybenzaldehyde was added to 30mL of acetonitrile and then injected into the three-necked flask using a syringe under nitrogen atmosphere. The flask was placed in a water bath and heated to 90℃ under reflux for 24h. After the reaction was completed, the mixture was allowed to cool naturally to room temperature. The residue was removed by suction filtration using a Buchner funnel. The filtrate was evaporated to dryness using a rotary evaporator. The product was extracted three times with ethyl acetate and saturated NaCl solution. The organic phase was dried over anhydrous sodium sulfate and filtered. After removing the remaining solvent by rotary evaporation at 40°C (unless otherwise specified, the steps of rotary evaporation, extraction, drying, filtration, and solvent removal are consistent with the preparation process of R1-1 described above), the crude product was purified by column chromatography (eluting ethyl acetate:methanol = 30:1, v / v) to obtain a white powder R1 (1.78 g). Its NMR data are as follows: 1 H NMR (400 MHz, Chloroform- d ) δ 9.82 (d, J =2.1 Hz, 1H), 7.37 (s, 2H), 6.93 (d, J = 8.1 Hz, 1H), 4.22 (s, 4H), 3.95 (dt, J =8.5, 4.0 Hz, 4H), 3.84 (t, J = 5.1 Hz, 4H).

[0033] (2) Synthesis of compound L1: Weigh 3g of p-hydroxybenzonitrile (CAS No.: 760-00-0) and 6.96g of potassium carbonate into a 250mL three-necked flask, insert a magnetic stir bar, evacuate, and purge with nitrogen. Repeat this process three times. Under normal pressure and nitrogen atmosphere, use a 25mL syringe to add 5.47g of 6-bromo-1-hexanol (CAS No.: 4286-55-9) and 80mL of acetonitrile into the flask respectively. Start stirring at 150rpm and stir for 5min to mix thoroughly. Then, heat the mixture to 85℃ in a water bath and reflux overnight. After the reaction was monitored to be complete by thin-layer chromatography and allowed to cool naturally to room temperature, anhydrous K₂CO₃ was removed by filtration. The remaining mixture was then evaporated at 60°C for 1.5 h to remove the solvent. The solvent was removed by rotary evaporation, and the mixture was poured into 35 mL of dichloromethane and extracted with 35 mL of saturated brine. The organic layer was dried with 3 g of anhydrous Na₂SO₄ and filtered. The remaining solvent was removed by rotary evaporation at 40°C for 20 min. Finally, the mixture was purified by column chromatography (petroleum ether:ethyl acetate = 2:1, v / v) as the eluent to obtain white crystals L1-1 (5.4 g). Its NMR data are as follows:1 H NMR (400MHz, Chloroform- d ) δ 7.61 – 7.53 (m, 1H), 6.97 – 6.89 (m, 1H), 4.00 (t, J = 6.5Hz, 1H), 3.66 (td, J = 6.5, 4.8 Hz, 1H), 3.42 (t, J = 6.8 Hz, 1H), 1.65 – 1.33 (m, 3H). Unless otherwise specified, the preparation steps of substances L1-2 to L1-7 below are consistent with the preparation process of L1-1.

[0034] Take a 250mL flask, weigh 1.4g of monomer L1-1, add it to 25mL of THF, stir manually with a glass rod for 2min, then place it in an ice bath at 0℃ and stir magnetically for 5min to mix it evenly. Then, add 0.39g of lithium aluminum hydride (CAS No.: 16853-85-3) to the flask in 4 portions, and let it stand at room temperature for 3h. After the reaction is complete, slowly add 5mL of ice water to quench the reaction, and then remove the remaining solvent by rotary evaporation at 60℃ for 20min. Add the crude product to 35mL of dichloromethane, add 30mL of saturated brine for extraction, add 2g of anhydrous Na2SO4 to dry the organic layer and filter, remove the remaining solvent by rotary evaporation at 40℃ for 20min, and finally purify by column chromatography with dichloromethane:methanol = 2:1 (v / v) as the eluent to obtain the white solid product L1-2 (1.11g). 1 H NMR (400 MHz, Chloroform- d ) δ 7.26 – 7.16 (m, 1H), 6.90 – 6.80 (m, 1H), 3.95 (t, J = 6.5 Hz, 1H), 3.79 (s, 1H), 3.64 (t, J = 6.6 Hz, 1H), 3.47 (s, 1H), 1.76 – 1.40 (m, 4H).

[0035] Take a 250mL dry three-necked flask, weigh 3g of p-hydroxybenzaldehyde (CAS No.: 123-08-0) and 5.09g of potassium carbonate, then put a magnetic stir bar into the flask, evacuate it, and purge it with nitrogen gas. Repeat this process three times. Under normal pressure and nitrogen atmosphere, use a 25mL syringe to add 5.34g of 6-bromo-1-hexanol and 20mL of N,N-dimethylformamide alternately in three portions into the flask. Turn on the stirring to 100rpm and stir for 5min to mix it evenly. Then heat the mixture in a water bath to 85℃ and react for 24h. After the reaction was complete and cooled naturally to room temperature, K₂CO₃ was removed by filtration. The remaining substance was added to 40 mL of dichloromethane and extracted with 40 mL of saturated brine. The organic layer was dried over 3 g of anhydrous Na₂SO₄ and filtered. The remaining solvent was removed by rotary evaporation at 40 °C for 20 min. Finally, the mixture was purified by column chromatography using petroleum ether:ethyl acetate = 4:1 (v / v) as the eluent, yielding a white oily substance L1-3 (5.18 g). Its NMR data are as follows: 1 HNMR (400 MHz, Chloroform- d ) δ 9.88 (s, 1H), 7.86 – 7.79 (m, 2H), 7.03 – 6.95 (m, 2H), 4.05 (t, J = 6.5 Hz, 2H), 3.67 (t, J = 6.5 Hz, 2H), 1.66 – 1.39 (m, 8H).

[0036] Weigh 0.88 g of monomer L1-2 and 0.876 g of monomer L1-3 into a three-necked flask, add 25 mL of methanol, stir manually with a glass rod for 2 min to mix thoroughly, then heat to 67 °C in a water bath and reflux overnight. After the reaction is complete, place it in an ice bath and cool to 0 °C. Then add 0.45 g of sodium borohydride (CAS No.: 16940-66-2) to the reaction system in three portions. After 1 h, remove the ice bath and react at room temperature for 4 h. After the reaction is complete, slowly add ice water to quench the reaction, and then remove the remaining solvent by rotary evaporation at 40 °C for 20 min. Add the crude product to 30 mL of dichloromethane and extract with 30 mL of saturated brine. Dry the organic layer with anhydrous Na2SO4 and remove the remaining solvent by rotary evaporation at 40 °C for 30 min. Finally, purify by column chromatography with dichloromethane:methanol = 9:1 (v / v) as the eluent to obtain the white solid product L1-4 (1.35 g). Its NMR data are as follows: 1 H NMR (400 MHz, Chloroform- d ) δ 7.24 (d, J = 17.4 Hz, 1H), 6.88 – 6.82 (m, 1H), 3.95 (t,J = 6.5Hz, 2H), 3.66 (t, J = 6.5 Hz, 1H), 1.53 – 1.37 (m, 4H).

[0037] A 250 mL three-necked flask was evacuated and purged with nitrogen three times. Under nitrogen atmosphere, 2.91 g of monomer L1-4, 20 mL of dichloromethane, 2.34 g of di-tert-butyl dicarbonate (CAS No.: 24424-99-5), and 1.42 g of triethylamine were added sequentially to the flask using a 25 mL syringe. Stirring was started to ensure homogeneity, and the mixture was allowed to stand overnight at room temperature. After the reaction was complete, the solvent was removed by rotary evaporation at 40 °C for 20 min. The crude product was added to 30 mL of dichloromethane and extracted with 30 mL of saturated brine. The organic layer was dried over anhydrous Na2SO4 and the solvent was removed by rotary evaporation at 40 °C for 15 min. The crude product was purified by column chromatography with dichloromethane:ethyl acetate as the eluent at a ratio of 2:1 (v / v) to obtain a pale yellow oily substance L1-5 (2.64 g). Its NMR data are as follows: 1 H NMR (400 MHz, Chloroform- d ) δ 7.14 (s, 1H), 6.88 – 6.80 (m, 1H), 4.27 (d, J = 30.0 Hz, 1H), 3.95 (t, J = 6.5 Hz, 1H), 3.67 (t, J = 6.6 Hz, 1H), 1.53 (d, J = 29.5 Hz, 6H).

[0038] Take a 250 mL p-bell flask, weigh 1 g of monomer L1-5, and add it to 25 mL of tetrahydrofuran. Then, add 2.2 mL of triethylamine to the p-bell flask, weigh 2.27 g of p-toluenesulfonyl chloride and pour it into a beaker, add 25 mL of THF, sonicate for 15 s, and slowly add it to the p-bell flask. Start stirring and stir at 200 rpm for 10 min to mix thoroughly. React at room temperature for 24 h. After the reaction is complete, remove the solvent by rotary evaporation at 50 °C for 20 min. Add the crude product to 30 mL of dichloromethane and extract with 30 mL of saturated brine. Dry the organic layer with anhydrous Na2SO4 and remove the solvent by rotary evaporation at 40 °C for 20 min. Finally, purify by column chromatography using dichloromethane:ethyl acetate = 1:1 (v / v) as the eluent to obtain a colorless oily product L1-6 (1.19 g). Its NMR data are as follows: 1 H NMR (400 MHz, Chloroform- d) δ 7.82 – 7.76 (m, 2H), 7.37 – 7.31 (m, 2H), 7.11 (s, 2H), 6.87 – 6.78 (m, 2H), 4.27 (d, J = 29.6 Hz, 2H), 4.04 (t, J = 6.4Hz, 2H), 3.90 (t, J = 6.4 Hz, 2H), 2.44 (s, 3H), 1.80 – 1.64 (m, 6H), 1.49 (s, 6H).

[0039] Weigh 0.33 g of p-hydroxybenzaldehyde and 1.123 g of potassium carbonate into a 250 mL three-necked flask, then add a magnetic stir bar, evacuate, and purge with nitrogen. Repeat this process three times. Under a nitrogen atmosphere, use a 25 mL syringe to add 1.19 g of monomer L1-6 and 80 mL of acetonitrile alternately in three portions to the flask. Stir until homogeneous, heat to 85 °C in a water bath, and reflux overnight. After the reaction is complete, cool to room temperature, remove K2CO3 by vacuum filtration, and remove the solvent by rotary evaporation at 50 °C for 20 min. Add the crude product to 35 mL of ethyl acetate, add 35 mL of saturated brine for extraction, dry the organic layer with anhydrous Na2SO4, and remove the solvent by rotary evaporation at 40 °C for 20 min. Finally, purify by column chromatography using dichloromethane:ethyl acetate = 100:1 (v / v) as the eluent to obtain a pale yellow oily substance L1-7 (0.45 g). Its NMR data are as follows: 1 H NMR (400 MHz, Chloroform- d ) δ9.88 (s, 1H), 7.86 – 7.79 (m, 2H), 7.12 (s, 2H), 6.98 (d, J = 2.0 Hz, 2H), 6.88– 6.81 (m, 2H), 4.27 (d, J = 28.0 Hz, 2H), 4.16 – 3.99 (dt, 4H), 1.84 (dt, J =13.4, 6.5 Hz, 4H), 1.50 (s, 8H).

[0040] The product L1-7 obtained in the previous step was added to 20 mL of dichloromethane, followed by 15 mL of 5.00 M hydrochloric acid solution. The mixture was stirred at 200 rpm for 12 h at room temperature, resulting in a white precipitate. This precipitate was then added to 20 mL of a 1:1 mixture of acetone and deionized water (50 °C), and 15 mL of saturated NH4PF6 aqueous solution was added, again resulting in a white precipitate. The mixture was allowed to stand for 30 min, filtered, and the filter cake was dried in an oven at 60 °C for 1 h to obtain the white solid product L1. Its NMR data are as follows: 1 H NMR (400MHz, Chloroform- d ) δ 9.82 (s, 1H), 7.81 – 7.73 (m, 2H), 7.31 – 7.25 (m, 3H), 7.02 – 6.93 (m, 2H), 6.90 – 6.83 (m, 2H), 4.12 – 4.02 (m, 4H), 3.91 (t, J = 6.3Hz, 2H), 1.82 (dp, J = 19.9, 6.8 Hz, 4H), 1.54 (h, J = 2.9 Hz, 4H).

[0041] Subject R1 (6.44 mg) and guest L1 (10.00 mg) were dissolved in 0.5 mL of THF at a molar ratio of 1:1, and then the two were mixed and sonicated for 5 min to prepare RL1.

[0042] Propyl-terminated polydimethylsiloxane (PDMS, Mw=20000, Shanghai Tangui) was dried in a vacuum oven at 80 °C for 2 h to remove moisture. One drop of dibutyltin dilaurate was added dropwise to a mixture of RL1 (2.6 mg) and PDMS (3.08 g), and the mixture was manually stirred with a glass rod for 2 min to ensure homogeneity. The mixture was then reacted at 60 °C for 12 h. Subsequently, 2 mL of a THF dispersion (0.01 g / mL) of the crosslinking agent 5'-(4-formylphenyl)-2',4',6'-trimethyl-[1,1':3',1''-terphenyl]-4,4''-dicarboxaldehyde (FTTD, 0.043 g) was slowly added, and the mixture was stirred at 200 rpm for 12 h. h, transfer it into a polytetrafluoroethylene mold (length: 60mm; width: 30mm; depth: 8mm) and let it stand for 3 hours, then put it in an oven and dry it at 50℃ for 24 hours to obtain supramolecular elastomer A.

[0043] The organosilicon supramolecular elastomer obtained in this embodiment was subjected to tensile testing. At room temperature, supramolecular elastomer A was cut into samples 4 cm long, 1 cm wide, and 0.3 cm thick, and placed in the fixture of a universal testing machine. The tensile rate was set to 30 mm / min. The results showed that the elastomer could be stretched approximately 10 times its original length, as indicated below. Figure 1 As shown.

[0044] Compared with the blank control group (RL1 was not added during the preparation of supramolecular elastomer A, and other steps remained unchanged), its elongation at break increased to ten times the original value, which shows that the addition of quasi-rotaxane can effectively improve the mechanical properties of elastomers, providing a basis for further research on elastomers with high tensile properties. Example 2

[0045] Unless otherwise specified, the preparation process in this embodiment is the same as in Example 1.

[0046] (1) First, aldehyde-modified benzo-24-crown-8 (R2) was synthesized.

[0047] Take a 250mL flask, weigh 5g of polyethylene glycol (CAS No.: 5617-32-3), and add it to 15mL of tetrahydrofuran. Then, add 7.5mL of 5g / mL sodium hydroxide solution to the flask, cool it to 0℃ in an ice bath, weigh 7.3g of p-toluenesulfonyl chloride and pour it into a beaker, add 15mL of THF, sonicate for 15s, and slowly add it to the flask. Start stirring and mix thoroughly. React at room temperature for 24h. After the reaction is complete, at 5... The solvent was removed by rotary evaporation at 0℃ for 20 min. The crude product was extracted with 30 mL of dichloromethane and 30 mL of saturated brine. The organic layer was dried with 3 g of anhydrous Na2SO4 and filtered. The remaining solvent was removed by rotary evaporation at 40℃ for 20 min. The crude product was purified by column chromatography with dichloromethane:ethyl acetate = 1:1 (v / v) as the eluent. The remaining solvent was removed by rotary evaporation at 40℃ for 15 min to obtain a colorless and transparent oily product R2-1 (8.66 g, yield 89%). 1 H NMR (400 MHz, Chloroform- d ) δ 7.82 – 7.75 (m, 2H), 7.36 – 7.30 (m, 2H), 4.20 –4.11 (m, 2H), 3.71 – 3.55 (m, 12H), 2.44 (s, 3H).

[0048] Weigh 0.44 g of 3,4-dihydroxybenzaldehyde, 742 g of anhydrous potassium carbonate, and 1.16 g of potassium hexafluorophosphate into a 250 mL three-necked flask. Add a magnetic stir bar, evacuate, and purge with nitrogen. Repeat this process three times. Under nitrogen atmosphere, add 2 g of monomer R2-1 and 80 mL of acetonitrile in three portions using a 25 mL syringe. Stir at 200 rpm to ensure homogeneity. Heat the mixture to 85 °C in a water bath and reflux overnight. After the reaction is complete, cool to room temperature. Remove anhydrous K2CO3 by filtration. Remove the solvent from the remaining solution by rotary evaporation at 50 °C for 20 min. Add the crude product to ethyl acetate and extract with saturated brine. Dry the organic layer with anhydrous Na2SO4 and filter. Remove the solvent by rotary evaporation at 40 °C for 15 min. Finally, purify by column chromatography using dichloromethane:methanol = 100:4 (v / v) as the eluent to obtain a white solid R2 (1.7 g). Its NMR data are as follows: 1 H NMR (400 MHz, Chloroform- d ) δ 9.81 (s, 1H), 7.49 – 7.37 (m, 1H), 6.94 (m, 2H), 4.27 – 4.17(m, 4H), 4.00 – 3.59 (m, 24H).

[0049] (2) Synthesis of secondary ammonium salt L2 with aldehyde groups at both ends: Weigh out 5.34g 4-(diethoxymethyl)benzaldehyde (CAS No.: 81172-89-6) and 3g of 6-bromo-1-hexanol were placed in a three-necked flask, 25mL of methanol was added, and the mixture was stirred until thoroughly mixed. The mixture was heated to 67℃ in a water bath and refluxed overnight. After the reaction was complete, the mixture was placed in an ice bath and the temperature was lowered to 0℃. 2.91g of sodium borohydride was added to the reaction system in three portions. After 1 hour, the ice bath was removed, and the reaction was allowed to proceed at room temperature for 4 hours. After the reaction was complete, 5 drops of ice water were slowly added to quench the reaction. The solvent was then removed by rotary evaporation at 60℃ for 20 minutes. The crude product was added to 30mL of dichloromethane and extracted with 30mL of saturated brine. The organic layer was dried with 3g of anhydrous Na2SO4 and the solvent was removed by rotary evaporation at 40℃ for 15 minutes. Finally, the product was purified by column chromatography with dichloromethane:methanol = 9:1 (v / v) as the eluent to obtain a white solid product, denoted as L2-1 (5.9g). Its NMR data are as follows: 1 H NMR (400MHz, Chloroform- d ) δ 7.45 – 7.38 (m, 1H), 7.30 (d, J= 7.9 Hz, 1H), 5.48 (s,1H), 3.77 (s, 1H), 3.67 – 3.42 (m, 3H), 2.61 (t, J = 7.2 Hz, 1H), 1.68 (s, 1H), 1.53 (tq, J = 13.7, 7.0 Hz, 2H), 1.35 (p, J = 4.0 Hz, 2H), 1.22 (t, J = 7.1 Hz, 3H).

[0050] A 250 mL three-necked flask was evacuated and purged with nitrogen three times. Under nitrogen atmosphere, a mixture of 2.87 g of monomer L2-1, 20 mL of dichloromethane, 3.19 mL of di-tert-butyl dicarbonate, and 1.93 mL of triethylamine was added to the flask using a 25 mL syringe. The mixture was stirred at 200 rpm until homogeneous and reacted overnight at room temperature. After the reaction was complete, the solvent was removed by rotary evaporation at 50 °C for 20 min. The crude product was added to 30 mL of dichloromethane and extracted with 30 mL of saturated brine. The organic layer was dried over 3 g of anhydrous Na2SO4 and then evaporated at 40 °C for 15 min. No further purification was required, yielding a pale yellow oil, denoted as L2-2 (2.9 g). Its NMR data are as follows: 1 H NMR (400 MHz, Chloroform- d ) δ 7.41 (d, J = 7.9 Hz, 2H), 7.21 (s, 2H), 5.48 (s, 1H), 4.38 (s, 2H), 3.67 – 3.54 (m, 6H), 3.55 – 3.45 (m, 2H), 1.58 – 1.27 (m, 23H). Take a 250ml flask, weigh 2.39g of monomer L2-2, and add it to 25mL of tetrahydrofuran. Then, weigh 2.22g of p-toluenesulfonyl chloride and pour it into a beaker, add 25mL of THF, sonicate for 15s, and slowly add it to the flask. Then add 3.24g of triethylamine, start stirring at 200rpm, mix thoroughly for 5min, and continue the reaction at room temperature for 24h. After the reaction is complete, remove the solvent by rotary evaporation at 50℃ for 20min. Add the crude product to 30mL of dichloromethane, add 30mL of saturated brine for extraction, dry the organic layer with 3g of anhydrous Na2SO4 and rotary evaporate at 40℃ for 15min. Finally, purify by column chromatography, using dichloromethane:methanol = 100:1 (v / v) as the eluent, to obtain a colorless oily product, denoted as L2-3 (2.6g). Its NMR data are as follows: 1H NMR (400 MHz, Chloroform- d ) δ 9.99 (s, 1H), 7.84 (d, J = 8.0 Hz, 2H), 7.77 (d, J =6.4 Hz, 2H), 7.35 (dd, J = 13.2, 7.8 Hz, 4H), 4.46 (d, J = 8.9 Hz, 2H), 3.99 (t, J = 6.4 Hz, 2H), 3.16 (d, J = 33.5 Hz, 2H), 2.43 (s, 3H), 1.53 – 1.16 (m, 17H).

[0051] Weigh 0.9 g of p-hydroxybenzaldehyde and 2.77 g of anhydrous potassium carbonate into a 250 mL three-necked flask, then add a magnetic stir bar, evacuate the flask, and purge with nitrogen. Repeat this process three times. Under a nitrogen atmosphere, use a 25 mL syringe to add 3.77 g of monomer L2-3 and 80 mL of acetonitrile into the flask in four portions. Stir at 200 rpm for 5 min to mix thoroughly. Then heat the mixture in a water bath to 85 °C and reflux overnight. After the reaction was complete and cooled naturally to room temperature, anhydrous K₂CO₃ was removed by filtration. The remaining mixture was rotary evaporated at 50°C for 20 min to remove the solvent. The crude product was added to 30 mL of ethyl acetate and extracted with 30 mL of saturated brine. The organic layer was dried with 3 g of anhydrous Na₂SO₄ and rotary evaporated at 40°C for 15 min to remove the solvent. Finally, it was purified by column chromatography using dichloromethane:methanol = 100:1 (v / v) as the eluent, yielding a pale yellow oil, denoted as L₂-4 (2.9 g). Its NMR data are as follows: 1 HNMR (400 MHz, Chloroform- d ) δ 9.99 (s, 1H), 9.87 (s, 1H), 7.82 (dd, J = 9.3, 7.3 Hz, 4H), 7.37 (d, J = 7.7 Hz, 2H), 7.00 – 6.93 (m, 2H), 4.48 (s, 2H), 4.01(t, J = 6.4 Hz, 2H), 3.22 (d, 2H), 1.64 – 1.28 (m, 17H).

[0052] The product L2-4 obtained in the previous step was added to 20 mL of dichloromethane, followed by 10 mL of 5.00 M hydrochloric acid solution. The mixture was stirred at 200 rpm for 12 h at room temperature, resulting in a white precipitate. This precipitate was then added to 20 mL of a mixture of acetone and deionized water (50 °C), and 30 mL of saturated NH4PF6 aqueous solution was added, again resulting in a white precipitate. The mixture was allowed to stand for 30 min, filtered, and the filter cake was dried in an oven at 80 °C for 1 h to obtain the white solid product L2. Its NMR data are as follows: 1 H NMR (400 MHz, Chloroform- d ) δ 10.04 (s, 1H), 9.86 (s, 1H), 8.01 – 7.94 (m, 2H), 7.88–7.80 (m, 2H), 7.69 – 7.62 (m, 2H), 7.09 – 7.01 (m, 2H), 6.90 (s, 2H), 4.24 (t, J =6.0 Hz, 2H), 4.08 (t, J = 6.4 Hz, 2H), 3.07 (dq, J = 11.2, 6.4 Hz, 2H), 1.85 –1.64 (m, 4H), 1.56 – 1.36 (m, 4H).

[0053] The main component R2 (8.82 mg) and the guest component L2 (10.00 mg) were dissolved in 0.7 mL of THF at a molar ratio of 1:1, and then the two were mixed and sonicated for 5 min to prepare RL2.

[0054] Propyl-terminated polydimethylsiloxane (Mw=3000, Shanghai Tangui) was dried in an oven at 80 °C for 2 h to remove moisture, then cooled to room temperature. One drop of dibutyltin dilaurate was added dropwise to a mixture of RL2 (18 mg) and PDMS (3.71 g), and the mixture was manually stirred with a glass rod for 2 min until homogeneous. Then, 1 mL of a THF solution of isoflurane diisocyanate (IPDI) (concentration 0.137 g / mL) was added, and the mixture was heated to 60 °C and reacted for 3 h. Subsequently, 6 mL of a THF solution of the crosslinking agent 5'-(4-formylphenyl)-2',4',6'-trimethyl-[1,1':3',1''-terphenyl]-4,4''-dicarboxaldehyde (FTTD) (concentration 0.028 g / mL) was slowly added, and the mixture was stirred at 200 rpm for 12 minutes. h, transfer it into a polytetrafluoroethylene mold (length: 60mm; width: 30mm; depth: 8mm) and let it stand for 3 hours, then put it in an oven and dry it at 50℃ for 24 hours to obtain a highly tensile supramolecular elastomer B.

[0055] The organosilicon supramolecular elastomer obtained in this embodiment was subjected to tensile testing. At room temperature, a sample measuring 4 cm in length, 1 cm in width, and 0.3 cm in thickness was placed in the fixture of a universal testing machine, and the tensile rate was set to 30 mm / min. The test results showed that the elastomer could be stretched approximately 30 times its original length, as shown below. Figure 2 As shown.

[0056] When 5% RL2 was added, compared with the blank group (no RL2 was added during the preparation of supramolecular elastomer B, and the other steps remained unchanged), its fracture strength increased from the original 0.25 MPa to 0.35 MPa, which is 6 times the original fracture strength. When quasi-rotaxane LR2 was introduced, the host-guest interaction in quasi-rotaxane would preferentially and reversibly dissociate before the chemical bonds broke when the material was under stress. That is, the slip ring structure of quasi-rotaxane would slide on the axis. At the same time, the hydrogen bonds formed between urea bonds, as sacrificial bonds, would work together to dissipate stress, ensuring that greater deformation would occur while the overall network of the material remained intact. This resulted in a simultaneous improvement in the strength and toughness of the material. Example 3

[0057] Aminopropyl-terminated polydimethylsiloxane (Mw=3000, Shanghai Tangui) was dried in an oven at 80 °C for 2 h to remove moisture, then cooled to room temperature. One drop of dibutyltin dilaurate was added dropwise to a mixture of RL2 (18 mg) and PDMS (3.49 g), and the mixture was thoroughly mixed. Then, 1 mL of a THF solution of isoflurone diisocyanate (IPDI) (concentration 0.137 g / mL) was added, and the mixture was heated to 60 °C and reacted for 3 h. Subsequently, 1 mL of a THF dispersion of dithiodiphenylamine (concentration 0.0184 g / mL) and 6 mL of a THF dispersion of the crosslinking agent 5'-(4-formylphenyl)-2',4',6'-trimethyl-[1,1':3',1''-terphenyl]-4,4''-dicarboxaldehyde (concentration 0.028 g / mL) were added. The mixture was stirred at 200 rpm for 24 hours. h, transfer to a PTFE mold and let stand for 30 minutes to obtain a highly tensile supramolecular elastomer C.

[0058] 1. Stress-strain testing The organosilicon supramolecular elastomer obtained in this embodiment was subjected to stress-strain testing. At room temperature, a sample measuring 4 cm in length, 1 cm in width, and 0.3 cm in thickness was placed in the fixture of a universal testing machine, and the tensile rate was set to 30 mm / min. The results showed that the elastomer could be stretched approximately 30 times its original length, as indicated below. Figure 3 As shown.

[0059] This elastomer possesses both high strength and high toughness because the introduction of dithiodiphenylamine into polyrotaxane silicone elastomer does not have a single effect, but rather is the result of the synergistic effect of multiple mechanisms.

[0060] 2. Cyclic tensile test The elastomer prepared in Example 3 was subjected to cyclic tensile testing at a tensile rate of 30 mm / min and a tensile strain set to 1500% of the raw material. The results are as follows: Figure 4 As shown in the figure, there is a clear hysteresis region between the loading and unloading curves of the elastomer, indicating that the material has the ability to dissipate energy. This shows that the addition of the supramolecular polymer network does indeed play a role in dissipation and increases the mechanical properties of the elastomer.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a highly tensile organosilicon supramolecular elastomer, characterized in that, The quasi-rotaxane structure is formed by combining an aldehyde-modified crown ether with a secondary ammonium salt through a host-guest interaction, and then the quasi-rotaxane structure is introduced into a polydimethylsiloxane prepolymer.

2. The method for preparing the highly tensile organosilicon supramolecular elastomer according to claim 1, characterized in that, The steps are as follows: (1) The aldehyde-modified benzo-24-crown-8 and the aldehyde-modified secondary ammonium salt were dispersed in tetrahydrofuran, mixed and sonicated to obtain quasi-rotaxane; (2) Prepare the elastomer using any of the following methods: Method 1: Quasi-rotaxane was added to a tetrahydrofuran dispersion of aminopropyl-terminated polydimethylsiloxane to obtain mixture A. A tetrahydrofuran dispersion of 5'-(4-formylphenyl)-2',4',6'-trimethyl-[1,1':3',1''-terphenyl]-4,4''-dicarboxaldehyde (FTTD) was slowly added to mixture A. Under inert gas protection, the mixture was stirred evenly and reacted. After the reaction was completed, the mixture was defoamed, poured into a mold, and dried to obtain polysiloxane elastomer A. Method 2: Quasi-rotaxane was added to a tetrahydrofuran dispersion of aminopropyl-terminated polydimethylsiloxane. After mixing evenly, a tetrahydrofuran dispersion of isophorone diisocyanate was added. After the reaction, reaction solution B was obtained. A tetrahydrofuran dispersion of 5'-(4-formylphenyl)-2',4',6'-trimethyl-[1,1':3',1''-terphenyl]-4,4''-dicarboxaldehyde was slowly added to reaction solution B. Under inert gas protection, the mixture was mixed evenly and the reaction was carried out. After the reaction was completed, the mixture was defoamed and poured into a mold. After drying, polysiloxane elastomer B was obtained. Method 3: Quasi-rotaxane was added to a tetrahydrofuran dispersion of aminopropyl-terminated polydimethylsiloxane. After mixing thoroughly, a tetrahydrofuran dispersion of isophorone diisocyanate was added. After reacting overnight, reaction solution C was obtained. Tetrahydrofuran dispersions of dithiodiphenylamine and 5'-(4-formylphenyl)-2',4',6'-trimethyl-[1,1':3',1''-terphenyl]-4,4''-dicarboxaldehyde (FTTD) were slowly added to reaction solution C. Under inert gas protection, the mixture was thoroughly mixed and reacted. After the reaction was completed, the mixture was defoamed, poured into a mold, and dried to obtain polysiloxane elastomer C.

3. The method for preparing the highly tensile organosilicon supramolecular elastomer according to claim 2, characterized in that, In step (1), the molar ratio of benzo-24-crown-8 and aldehyde-modified secondary ammonium salt is 1:

1.

4. The method for preparing the highly tensile organosilicon supramolecular elastomer according to claim 2, characterized in that, In step (2) Method 1, the molecular weight of the aminopropyl-terminated polydimethylsiloxane is 1000-20000; the molar ratio of the aminopropyl-terminated polydimethylsiloxane to 5'-(4-formylphenyl)-2',4',6'-trimethyl-[1,1':3',1''-terphenyl]-4,4''-dicarboxaldehyde and quasi-rotaxane is 150:(99-80):(1-20).

5. The method for preparing the highly tensile organosilicon supramolecular elastomer according to claim 2, characterized in that, In step (2) Method 2, the molecular weight of aminopropyl-terminated polydimethylsiloxane is 1000-20000; the molar ratio of aminopropyl-terminated polydimethylsiloxane, isophorone diisocyanate, 5'-(4-formylphenyl)-2',4',6'-trimethyl-[1,1':3',1''-terphenyl]-4,4''-dicarboxaldehyde (FTTD) and quasi-rotaxane is 300:150:(99-90):(1-10).

6. The method for preparing the highly tensile organosilicon supramolecular elastomer according to claim 2, characterized in that, In step (2) Method 3, the molecular weight of aminopropyl-terminated polydimethylsiloxane is 1000-20000; the molar ratio of aminopropyl-terminated polydimethylsiloxane, dithiodiphenylamine, isophorone diisocyanate, 5'-(4-formylphenyl)-2',4',6'-trimethyl-[1,1':3',1''-terphenyl]-4,4''-dicarboxaldehyde (FTTD), and quasi-rotaxane is (297-270):(3-30):150:(99-90):(1-10).

7. The method for preparing the highly tensile organosilicon supramolecular elastomer according to claim 2, characterized in that, Dibutyltin dilaurate is used as a catalyst in step (2) of the reaction process.

8. An organosilicon supramolecular elastomer, characterized in that, It is prepared by any one of the methods of claims 2-7.

9. The use of the organosilicon supramolecular elastomer of claim 8 as a toughening agent.

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