Marine resistant and damage resistant skin-like elastomer, and preparation method and application thereof

Abstract

The application relates to a seawater-resistant and damage-resistant skin-like elastomer and a preparation method and application thereof, which are obtained by introducing cation-pi interaction into a polyurethane preparation process to induce the formation of dense nano-phase hydrogen bond clusters. The application has good mechanical properties, damage resistance and seawater resistance of cephalopod skin, has high potential in underwater application in the exploration and utilization of marine resources, especially in coping with the challenges brought by the harsh marine environment, and has good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of polymer elastomer technology, and specifically relates to a skin-like elastomer that is resistant to seawater and damage, as well as its preparation method and application. Background Technology

[0002] Over hundreds of millions of years of evolution, organisms in nature have developed a high degree of rationality, scientific rigor, and advancement in many aspects. Among the numerous aquatic and terrestrial species, cephalopods possess complex deformability, dynamic optical camouflage, and environmental perception capabilities due to their unique protein systems. For a long time, researchers have used squid skin as a source of bio-inspiration for developing smart materials, such as soft robots [Angew. Chem. Int. Ed. 2011, 50, 1890; Nature 2015, 521, 467; Sci. Robot. 2023, 8, eadh7852; Chin. J. Polym. Sci. 2022, 40, 384; Adv. Fiber Mater. 2022, 4, 1209; Adv. Fiber Mater. 2022, 4, 98] and adhesives [Nature 2017, 546, 396; Smart Mater. Med. 2023, 4, 294]. Squid skin exhibits strain-hardening mechanical behavior; initially soft and supple, the skin rapidly hardens under intense deformation, resulting in an increase in elastic modulus by several orders of magnitude to prevent damage. Furthermore, squid skin is extremely tough, resisting tearing, puncture, and seawater, which protects squid from predators and allows them to survive in harsh environments.

[0003] Inspired by the skin structure of cephalopods, different networks with varying stiffnesses were integrated to simulate strain hardening properties through asymptotic responses to strain. [Nat. Commun. 2020, 11, 1107; Nat. Commun. 2021, 12, 4082; Adv. Mater. 2020, 32, 2003761] Sheiko et al. developed bottle brush elastomers containing flexible strands and rigid backbones to replicate skin-like mechanical behavior. [Science 2018, 359, 1509] Skin-like elastomers with hybrid crosslinked networks were developed by combining covalent and hydrogen bonds into a single network. [Adv. Fiber Mater. 2022, 4, 98] Wu et al. developed self-healing skin-like ionic elastomers by introducing an entropy-driven supramolecular zwitterionic reconfigurable network into a hydrogen-bonded network.

[0004] However, most reported skin-like elastomers typically encounter several problems that severely hinder their further application. These elastomers often employ low crosslinking density and weak crosslinking to ensure their inherent softness, resulting in poor strength and tear resistance. Furthermore, most physical crosslinks are susceptible to environmental factors such as water or ions. The inevitable swelling and breakage of physical bonds due to the influence of salt ions on elastomer strength severely impede their application in sweat or marine environments. Therefore, a novel molecular design is needed to combine these properties into a synthetic elastomer. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a skin-like elastomer that is resistant to seawater and damage, as well as its preparation method and application. The elastomer has good mechanical properties, damage resistance and seawater resistance similar to cephalopod skin.

[0006] This invention provides a skin-like elastomer that is resistant to seawater and damage, obtained by introducing cation-π interactions into the polyurethane preparation process to induce the formation of a dense nanophase with hydrogen bond clusters.

[0007] Preferably, the cation-π interaction is provided by one or more aromatic groups including indole, benzene, pentafluorobenzene, pyrrole, and naphthalene, and by one or more cationic groups including lithium sulfonate, sodium sulfonate, potassium sulfonate, and quaternary ammonium salt.

[0008] Preferably, the polyurethane is obtained by reacting polyether polyol or polyester polyol with polyisocyanate.

[0009] Preferably, the polyisocyanate includes one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, hexamethylene diisocyanate trimer, dicyclohexylmethane diisocyanate, phenylmethane diisocyanate, triphenylmethane triisocyanate, L-lysine triisocyanate, and polymethylene polyphenyl polyisocyanate.

[0010] Preferably, the polyether polyol includes one or more of polytetramethylene ether glycol, polypropylene glycol, polyethylene glycol, and polyglycerol; the weight-average molecular weight of the polyether polyol is 500-10000; the polyester polyol includes one or more of polyhexyl adipate diol, polybutylene adipate diol, polypropylene adipate diol, polyethylene adipate diol, polybutylene phthalate diol, polycaprolactone diol, and polycaprolactone triol; the weight-average molecular weight of the polyester polyol is 500-10000.

[0011] Preferably, the general structural formula of the skin-like elastomer is:

[0012]

[0013] The numerical range of x, y, and z is 1-40.

[0014] This invention also provides a method for preparing a skin-like elastomer that is resistant to seawater and damage, comprising the following steps:

[0015] (1) Indole-3-carboxaldehyde and 2-amino-1,3-propanediol were mixed at a molar ratio of 1:(1-1.5) and refluxed for 24 hours under the action of a catalyst. The aromatic monomer IAPD was obtained after post-treatment.

[0016] (2) Weigh out polyether polyol or polyester polyol and sodium N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate at a molar ratio of 1:(0.13-0.33). Add polyisocyanate at a molar ratio of 1:(1.25-1.67) with polyether polyol or polyester polyol to the reaction flask under nitrogen atmosphere and stir for 4-6 hours. Add aromatic monomer IAPD at a molar ratio of 1:(0.13-0.33) with polyether polyol or polyester polyol to the reaction flask under nitrogen atmosphere and react at 80-90℃ for 12-18 hours. Vacuum dry to constant weight to obtain a skin-like elastomer resistant to seawater and damage.

[0017] Preferably, the mixed solvent in step (1) is one or more of ethanol, methanol, and N,N'-dimethylformamide.

[0018] Preferably, the catalyst in step (1) is one or more of acetic acid and sodium carbonate.

[0019] The reaction equation of this invention is as follows:

[0020]

[0021] This invention also provides an application of a seawater-resistant and damage-resistant skin-like elastomer in the fields of marine resource exploration and utilization, medical devices, etc.

[0022] The principle of this invention is as follows:

[0023] Introducing cation-π interactions into polyurethane induces the formation of a dense nanophase with hydrogen-bonded clusters, thereby giving the elastomer skin-like mechanical behavior and damage resistance. At the same time, high-concentration salt solutions reduce electrostatic repulsion between ions, decrease the distance between molecular chains, and increase cation-π interactions, thus protecting the hydrogen-bonded cluster nanophase from seawater corrosion and giving the elastomer seawater resistance, making it suitable for underwater applications in the exploration and utilization of marine resources.

[0024] Beneficial effects

[0025] This invention possesses excellent mechanical properties, damage resistance, and seawater resistance similar to cephalopod skin, and has great potential for underwater applications in the exploration and utilization of marine resources, especially in addressing the challenges posed by harsh marine environments, demonstrating promising application prospects. Attached Figure Description

[0026] Figure 1 A schematic diagram (a) of the structure of cephalopod skin and a schematic diagram (b) of the structure of the elastomer of the present invention.

[0027] Figure 2 This is the infrared spectrum of the elastomer of the present invention.

[0028] Figure 3 The mechanical properties of the elastomer of this invention are described.

[0029] Figure 4 This refers to the tear resistance of the elastomer of the present invention.

[0030] Figure 5 ab represents the puncture resistance of the elastomer of this invention.

[0031] Figure 6 ab represents the long-term seawater resistance of the elastomer of this invention.

[0032] Figure 7 The 1H NMR spectrum is for the monomer IAPD. Detailed Implementation

[0033] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0034] Example 1

[0035] The preparation of the seawater-resistant and damage-resistant skin-like elastomer of the present invention includes the following steps:

[0036] Step 1: Preparation of the aromatic monomer IAPD

[0037] Indole-3-carboxaldehyde and 2-amino-1,3-propanediol were mixed in a molar ratio of 1:1, dissolved in 100 mL of ethanol, and refluxed for 24 hours with 6 drops of acetic acid catalyst. Magnesium sulfate was removed by filtration, some solvent was removed by rotary evaporation, and ethyl acetate was added for recrystallization to obtain a pale yellow solid IAPD monomer, which was dried under vacuum to constant weight.

[0038] The reaction equation for the IAPD is shown below:

[0039]

[0040] The proton spectrum of the IAPD is as follows: Figure 7 As shown, the data are as follows: 11.45 ppm is the chemical shift of the amino group in indole, 7.07-8.44 ppm is the chemical shift of the benzene ring and -N=CH- double bond in the imine group of indole, and 3.16-4.48 ppm is the chemical shift of CH and CH2 in the propylene glycol group.

[0041] Step 2: Preparation of skin-like elastomer ISPU

[0042] Weigh out 2000 molecular weight polytetrahydrofuran (PTMG) and sodium N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate (BES-Na) in a 250 mL Shrek flask at a molar ratio of 1:0.13 and remove moisture under vacuum at 90 °C. After cooling to 85 °C, dissolve hexamethylene diisocyanate (HDI) with a molar ratio of 1:1.25 to PTMG in 5 mL of N,N-dimethylformamide (DMF) under nitrogen atmosphere, add to the reaction flask, and stir for 4 hours. Dissolve the aromatic monomer IAPD with a molar ratio of 1:0.13 to PTMG in 5 mL of DMF, add to the reaction flask under nitrogen atmosphere, and react at 85 °C for 12 hours. After the reaction is complete, precipitate the product in diethyl ether, dry under vacuum to constant weight, and obtain a pale yellow solid ISPU elastomer. The ISPU elastomer was dissolved in tetrahydrofuran, and the resulting solution was poured into a polytetrafluoroethylene mold. The mold was placed in an oven at 40°C for 48 hours to remove the solvent. Then, the mold was evacuated and placed at 80°C for 24 hours to remove the remaining solvent, thus obtaining the ISPU elastomer film.

[0043] Example 2

[0044] This embodiment is basically the same as Example 1, except that in the first step of preparing the aromatic monomer IAPD, the ratio of indole-3-carboxaldehyde and 2-amino-1,3-propanediol is 1:1.2.

[0045] Example 3

[0046] This embodiment is basically the same as Example 1, except that in the first step of preparing the aromatic monomer IAPD, the ratio of indole-3-carboxaldehyde and 2-amino-1,3-propanediol is 1:1.5.

[0047] Example 4

[0048] This embodiment is basically the same as Embodiment 1, except that in the second step of preparing the skin-like elastomer ISPU film, the ratio of PTMG, BES-Na, IAPD and HDI is 1:0.21:0.21:1.43.

[0049] Example 5

[0050] This embodiment is basically the same as Embodiment 1, except that in the second step of preparing the skin-like elastomer ISPU film, the ratio of PTMG, BES-Na, IAPD and HDI is 1:0.33:0.33:1.67.

[0051] The performance testing method is as follows:

[0052] Polymer films were cut into dumbbell-shaped strips of 20mm × 4mm × 0.4mm and stretched to fracture using a universal tensile testing machine at a rate of 50mm / min. The tensile mechanical properties were measured. For fracture energy testing, single-sided notched specimens (slit length 1mm) were used. Polymer films were cut into notched and unnotched dumbbell shapes of 20mm × 4mm × 0.4mm and subjected to tensile testing at a stretching rate of 50mm / min. Fracture energy (G) c ) Calculated by the following formula: Polymer samples with an average thickness of 0.8 mm were subjected to puncture resistance testing according to standard GB / T 37841-2019. The polymer film was cut into dumbbell-shaped strips of 20 mm × 4 mm × 0.4 mm, immersed in 0.7 M sodium chloride aqueous solution, and stretched until fractured using a universal tensile testing machine at a rate of 50 mm / min. The tensile mechanical curve after immersion was measured.

[0053] The performance test results are as follows:

[0054] (1) Figure 2 This is the infrared spectrum of the elastomer ISPU prepared in Example 5, 1210 cm⁻¹. -1 and 1040cm -1 The peak at 997 cm⁻¹ is a characteristic peak of the sulfonic acid group (-S(=O)₂). -1 and 746cm -1 The peaks at these locations are characteristic of the carbon-nitrogen bond (-CN-) of the indole ring and the aromatic ring.

[0055] (2) Figure 3 The figures are the tensile mechanical curves of the elastomer ISPU prepared in Examples 3-5. The engineering stress of Example 3 was 8.5 MPa and the elongation at break was 1598%. The engineering stress of Example 4 was 26.1 MPa and the elongation at break was 1197%. The engineering stress of Example 5 was 35.3 MPa and the elongation at break was 1122%.

[0056] (3) Figure 4 The notched tensile mechanical properties curve of the elastomer ISPU prepared in Example 5 shows a calculated tear resistance of 103.7 kJ / m. -2 .

[0057] (4) Figure 5This is a photograph of the puncture test of the elastomer ISPU prepared in Example 5. Figure 5 a) and puncture mechanics curve ( Figure 5 b) The puncture force is 34.4 N.

[0058] (5) Figure 6 The tensile mechanical properties of the elastomer ISPU prepared in Example 5 before and after immersion in a 0.7M sodium chloride aqueous solution for 14 days are shown. Figure 6 a) and physical pictures ( Figure 6 (b) The stress retention rate of the elastomer was 99% after 14 days.

Claims

1. A skin-like elastomer resistant to seawater and damage, characterized in that: The general structural formula of the skin-like elastomer is: Wherein, the values ​​of x, y, and z range from 1 to 40; the polyurethane is obtained by introducing cation-π interaction into the polyurethane preparation process to induce the formation of a dense nanophase with hydrogen bond clusters; the polyurethane is obtained by reacting polytetramethylene ether glycol and hexamethylene diisocyanate; the weight average molecular weight of the polytetramethylene ether glycol is 500-10000.

2. A method for preparing a seawater-resistant and damage-resistant skin-like elastomer as described in claim 1, comprising the following steps: (1) Indole-3-carboxaldehyde and 2-amino-1,3-propanediol were mixed at a molar ratio of 1:(1-1.5) and refluxed for 24 hours under the action of a catalyst. The aromatic monomer IAPD was obtained after post-treatment. (2) Weigh out polytetramethylene ether glycol and sodium N,N-di(2-hydroxyethyl)-2-aminoethanesulfonate at a molar ratio of 1:(0.13-0.33). Add hexamethylene diisocyanate at a molar ratio of 1:(1.25-1.67) with polytetramethylene ether glycol to the reaction flask under nitrogen atmosphere and stir for 4-6 hours. Add aromatic monomer IAPD at a molar ratio of 1:(0.13-0.33) with polytetramethylene ether glycol to the reaction flask under nitrogen atmosphere and react at 80-90℃ for 12-18 hours. Vacuum dry to constant weight to obtain a skin-like elastomer resistant to seawater and damage.

3. The preparation method according to claim 2, characterized in that: The mixed solvent in step (1) is one or more of ethanol, methanol, and N,N'-dimethylformamide.

4. The preparation method according to claim 2, characterized in that: The catalyst in step (1) is one or more of acetic acid and sodium carbonate.

5. The application of a seawater-resistant and damage-resistant skin-like elastomer as described in claim 1 in marine resource exploration and utilization and medical devices.

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