A method for preparing tear-resistant elastic gel

Abstract

This invention discloses a method for preparing a tear-resistant elastic gel, comprising the following steps: adding monomer molecules, a crosslinking agent, and a nano-confined material to a solvent, and performing a polymerization reaction under ultraviolet light irradiation in the presence of a photoinitiator to obtain the tear-resistant elastic gel. This invention utilizes the polymerization of monomer molecules and crosslinking agents initiated by a photoinitiator within the confined space of the nano-confined material. The strong hydrogen bonding between interpenetrating polymer segments effectively immobilizes polymer chains that may slide under load, preventing energy dissipation. Simultaneously, the rigid nano-confined material prevents stress concentration at crack tips in the host material and significantly reduces the crack propagation sensitivity of the prepared gel, thereby improving the strength, strain, crack propagation resistance, and elasticity under ultimate deformation of the gel material, thus obtaining a tear-resistant elastic gel.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and more specifically to a method for preparing tear-resistant elastic gel. Background Technology

[0002] Hydrogels, ionogels, and organogels are widely used in smart sensors, actuators, drug delivery, wound healing, tissue engineering, shock protection, coatings, and other cutting-edge technologies. The application range and lifespan of a gel depend on its tensile strength, elasticity, and crack propagation sensitivity. However, polymer chain breakage leads to crack propagation in mono-network gels due to their lack of effective energy dissipation mechanisms. Therefore, existing technologies, including dual-network, hydrogen bond reinforcement, nanocomposites, and crystallization strategies, have been used to enhance gels. While these strategies improve the fracture strength and toughness of gels, sacrificing structural energy dissipation and reversible bonds results in significant hysteresis and residual strain, sacrificing gel elasticity. Furthermore, stress concentration at the crack tip cannot be effectively dissipated, leading to catastrophic propagation. Existing technologies report gel ultimate fracture strains of less than 5000%, elastic deformation ranges of less than 500%, and crack propagation strains of less than 1000%. Therefore, developing high-strength, tear-resistant elastic gels to improve their application range and lifespan to meet the needs of actuators, drug delivery, wound healing, tissue engineering, shock protection, coatings, and other fields has become an urgent need. Summary of the Invention

[0003] To address the aforementioned technical problems, the present invention aims to provide a method for preparing tear-resistant elastic gels. This method involves the polymerization of monomer molecules and crosslinking agents within the confined space of a nano-confined material initiated by a photoinitiator, thereby enhancing the strength, strain, crack propagation resistance, and elasticity under extreme deformation of the gel material.

[0004] This invention is achieved through the following technical solution:

[0005] A method for preparing a tear-resistant elastic gel includes the following steps: adding monomer molecules, crosslinking agents and nano-confined materials to a solvent, and carrying out a polymerization reaction by ultraviolet light irradiation in the presence of a photoinitiator to obtain the tear-resistant elastic gel.

[0006] This invention utilizes a photoinitiator to initiate the polymerization of monomer molecules and crosslinking agents within the confined space of a nano-confined material. The monomer molecules diffuse into the confined space of the nano-confined material for polymerization. Strong hydrogen bonds between interpenetrating polymer segments and the nano-confined material effectively immobilize polymer chains that might slide under load, thus preventing energy dissipation. The introduction of confined nanoparticles increases polymer entanglement. Rigid confined nanoparticles can act as stress transfer and dissipation centers, eliminating the catastrophic crack propagation and material fracture failure that could result from stress concentration caused by chain breakage. The low crosslinking and high entanglement in the network topology exhibit higher tensile strength, elasticity, and toughness. Unlike crosslinking, entanglement does not make the gel brittle. Tight entanglement allows tension in the polymer chains to be transferred to other chains, and the elastic energy generated when long chains break can be dissipated. Simultaneously, the rigid nano-confined material prevents stress concentration at crack tips in the host material and significantly reduces the crack propagation sensitivity of the prepared gel, thereby improving the strength, strain, crack propagation resistance, and elasticity under ultimate deformation of the gel material, resulting in a tear-resistant elastic gel.

[0007] Furthermore, the gel includes hydrogels, ionic gels, and organic gels.

[0008] In a specific embodiment, the method for preparing the tear-resistant elastic gel includes the following steps:

[0009] S1. Add monomer molecules, crosslinking agents, nano-confined materials and photoinitiators to a solvent and dissolve them, then stir for 5-10 hours to obtain a mixture;

[0010] S2. Place the mixture under a UV lamp for photo-initiated polymerization for 3-100 min to obtain the tear-resistant elastic gel.

[0011] Furthermore, step S2 is performed at 10–30°C, and the ultraviolet light wavelength of the ultraviolet lamp is 360–420 nm, with a power preferably of 10–500 W.

[0012] Furthermore, the nanoconfined material is one or more of the following: covalent organic frameworks (COFs), molecular sieves, porous ionomers, carbon nanospheres, graphene, and carbon nanotubes.

[0013] Furthermore, the covalent organic framework can be TpPa-1, β-ketoenamine COFs, polyimide-linked COFs, triazine-linked COFs, or imine-linked COFs, including but not limited to TpPa-1, β-ketoenamine COFs, PI-COF-1, TPB-TP-COF, and CTF-1.

[0014] Furthermore, the molecular sieve can be any of the molecular sieves currently reported, preferably SBA-15.

[0015] Furthermore, the monomer molecules include, but are not limited to, one or more of acrylamide, N,N-dimethylacrylamide, hydroxyethyl acrylate, methyl acrylate, ethyl acrylate, butyl acrylate, 2-acrylamido-2-methyl-1-propanesulfonic acid, and acrylic acid.

[0016] Furthermore, the crosslinking agent is N,N-methylenebisacrylamide, polyethylene glycol diacrylate (PEGDA), pentaerythritol triacrylate, or pentaerythritol tetraacrylate.

[0017] Furthermore, the molecular weight of the polyethylene glycol diacrylate is 200 to 10,000.

[0018] Furthermore, the solvent is a conventional solvent for preparing gel materials, which can be water, ionic liquid or organic solvent, preferably glycerol or ethylene glycol.

[0019] Furthermore, the photoinitiator is a conventional photoinitiator for preparing gel materials, and can be 1-hydroxycyclohexylphenyl ketone.

[0020] Furthermore, the mass ratio of the crosslinking agent to the monomer molecules is 1:(200-10000).

[0021] Furthermore, the mass ratio of the nanoconfined material to the monomer molecule is 1:(100-10000).

[0022] Furthermore, the mass ratio of the photoinitiator to the monomer molecule is 1:(50-1000).

[0023] Furthermore, the mass ratio of the monomer molecule to the solvent is 1:(0.5-6).

[0024] Furthermore, in summary, the mass ratio of crosslinking agent, nano-confined material, photoinitiator, solvent and monomer molecules is (0.0001~0.005):(0.0001~0.01):(0.001~0.02):(0.5~6):1.

[0025] The beneficial effects of this invention are:

[0026] This invention utilizes a photoinitiator to initiate the polymerization of monomer molecules and crosslinking agents within the confined space of a nano-confined material. The strong hydrogen bonding between interpenetrating polymer segments effectively immobilizes polymer chains that may slide under load, preventing energy dissipation. Simultaneously, the rigid nano-confined material prevents stress concentration at crack tips in the host material and significantly reduces the crack propagation sensitivity of the prepared gel. This enhances the strength, strain, crack propagation resistance, and elasticity under ultimate deformation of the gel material, resulting in a tear-resistant elastic gel with an ultimate fracture strain reaching up to 17000%, an elastic deformation range of 0–8000%, and a crack propagation strain of 5800%. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the tear-resistant elastic gel provided by the present invention.

[0028] Figure 2 This is a schematic diagram of the structure of the nanoconfined material used in this invention.

[0029] Figure 3 This is a stress-strain curve of the tear-resistant elastic gel prepared in Example 1 of the present invention.

[0030] Figure 4 This is a stress-strain curve of the elastic gel prepared in Comparative Example 1 of this invention.

[0031] Figure 5 This is a cyclic tensile stress-strain curve of the tear-resistant elastic gel prepared in Example 1 of the present invention at a strain of 8000%.

[0032] Figure 6 This is a cyclic tensile stress-strain curve of the elastic gel prepared in Comparative Example 1 of the present invention at a strain of 2000%.

[0033] Figure 7 This is a stress-strain curve of the tear-resistant elastic gel prepared in Example 2 of the present invention.

[0034] Figure 8 This is a cyclic tensile stress-strain curve of the tear-resistant elastic gel prepared in Example 2 of the present invention at a strain of 6000%. Detailed Implementation

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0036] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0037] The present invention discloses a method for preparing a tear-resistant elastic gel, comprising the following steps: adding monomer molecules, crosslinking agents and nano-confined materials to a solvent, and performing a polymerization reaction by irradiation with ultraviolet light in the presence of a photoinitiator to obtain the tear-resistant elastic gel.

[0038] like Figure 1 As shown, this invention involves the polymerization of monomer molecules and crosslinking agents initiated by a photoinitiator within the confined space of a nano-confined material. The monomer molecules diffuse into the confined space of the nano-confined material for polymerization. The strong hydrogen bonding between the interpenetrating polymer segments and the nano-confined material effectively immobilizes polymer chains that may slide under load, thus preventing energy dissipation. The introduction of confined nanoparticles increases polymer entanglement. Rigid confined nanoparticles can act as stress transfer and dissipation centers, eliminating the catastrophic crack propagation and material fracture failure that may result from stress concentration caused by chain segment breakage. The low crosslinking and high entanglement in the network topology exhibit higher tensile strength, elasticity, and toughness. Unlike crosslinking, entanglement does not make the gel brittle. Tight entanglement allows tension in the polymer chains to be transferred to other chains, and the elastic energy generated when long chains break can be dissipated. Simultaneously, the rigid nano-confined material prevents stress concentration at crack tips in the host material and significantly reduces the crack propagation sensitivity of the prepared gel, thereby improving the strength, strain, crack propagation resistance, and elasticity under ultimate deformation of the gel material, resulting in a tear-resistant elastic gel.

[0039] In specific embodiments, the nanoconfined material is one or more of the following: covalent organic framework, molecular sieve, porous ionomer, carbon nanospheres, graphene, and carbon nanotubes.

[0040] In specific embodiments, the nanoconfined material can be TpPa-1, PI-COF-1, TPB-TP-COF, CTF-1, or molecular sieves (MSs), with the following structural formula: Figure 2 As shown.

[0041] In a specific embodiment, the method for preparing the tear-resistant elastic gel includes the following steps:

[0042] S1. Add monomer molecules, crosslinking agents, nano-confined materials and photoinitiators to a solvent and dissolve them, then stir for 5-10 hours to obtain a mixture;

[0043] S2. Place the mixture under a UV lamp for photo-initiated polymerization for 3-100 min to obtain the tear-resistant elastic gel.

[0044] The ultraviolet lamps used in the following examples have an ultraviolet wavelength of 365nm and a power of 48W.

[0045] Example 1

[0046] A method for preparing a tear-resistant elastic gel includes the following steps:

[0047] S1. Dissolve 2g acrylamide, 0.002g polyethylene glycol diacrylate (molecular weight 1000), 0.002g TpPa-1 and 0.01g 1-hydroxycyclohexyl benzophenone in 4g water and stir for 5h to obtain a uniformly dispersed mixture;

[0048] S2. Place the mixture under a UV lamp for photo-initiated polymerization for 20 minutes to obtain the tear-resistant elastic gel.

[0049] Example 2

[0050] A method for preparing a tear-resistant elastic gel includes the following steps:

[0051] S1. Dissolve 2g acrylamide, 0.002g polyethylene glycol diacrylate (molecular weight 1000), 0.002g SBA-15 (pore size 5nm) and 0.01g 1-hydroxycyclohexyl benzophenone in 4g water and stir for 5h to obtain a uniformly dispersed mixture.

[0052] S2. Place the mixture under a UV lamp for photo-initiated polymerization for 20 minutes to obtain the tear-resistant elastic gel.

[0053] Example 3

[0054] A method for preparing a tear-resistant elastic gel includes the following steps:

[0055] S1. Add 2g acrylamide, 0.01g polyethylene glycol diacrylate (molecular weight 1000), 0.002g TpPa-1 and 0.02g 1-hydroxycyclohexyl benzophenone to 4g ionic liquid [EMIM]TFSI and dissolve. Stir for 5h to obtain a uniformly dispersed mixture.

[0056] S2. Place the mixture under a UV lamp for photo-initiated polymerization for 20 minutes to obtain the tear-resistant elastic gel.

[0057] Example 4

[0058] A method for preparing a tear-resistant elastic gel includes the following steps:

[0059] S1. Add 2g of methyl acrylate, 0.0002g of N,N-methylenebisacrylamide, 0.0002g of porous ionomer and 0.002g of 1-hydroxycyclohexyl benzophenone to 1g of glycerol and dissolve. Stir for 5h to obtain a uniformly dispersed mixture.

[0060] S2. Place the mixture under a UV lamp for photo-initiated polymerization for 20 minutes to obtain the tear-resistant elastic gel.

[0061] Example 5

[0062] A method for preparing a tear-resistant elastic gel includes the following steps:

[0063] S1. Add 2g of 2-acrylamido-2-methyl-1-propanesulfonic acid, 0.01g of pentaerythritol triacrylate, 0.02g of graphene and 0.04g of 1-hydroxycyclohexyl phenyl ketone to 12g of ethylene glycol and dissolve. Stir for 5h to obtain a uniformly dispersed mixture.

[0064] S2. Place the mixture under a UV lamp for photo-initiated polymerization for 20 minutes to obtain the tear-resistant elastic gel.

[0065] Comparative Example 1

[0066] A method for preparing an elastic gel includes the following steps:

[0067] S1. Dissolve 2g acrylamide, 0.002g polyethylene glycol diacrylate (molecular weight 1000) and 0.01g 1-hydroxycyclohexyl benzophenone in 4g water and stir for 5h to obtain a uniformly dispersed mixture;

[0068] S2. Place the mixture under a UV lamp for photo-initiated polymerization for 20 minutes to obtain the elastic gel.

[0069] The tear-resistant elastic gels prepared in Examples 1-5 and the elastic gel prepared in Comparative Example 1 were tested, and the test results are as follows:

[0070] Figure 3 This is a stress-strain curve of the tear-resistant elastic gel prepared in Example 1 of the present invention. Figure 4 This is a stress-strain curve of the elastic gel prepared in Comparative Example 1 of the present invention. As can be seen from the figure, compared with the method of preparing elastic gel without adding nano-confined materials in Comparative Example 1, the nano-confined polymerization method of adding covalent organic framework TpPa-1 in Example 1 significantly improves the mechanical properties of the gel, with the ultimate fracture strain reaching 17000%, and the fracture strain increased by nearly 4 times.

[0071] Figure 5This is a cyclic tensile stress-strain curve of the tear-resistant elastic gel prepared in Example 1 of this invention at a strain of 8000%. Figure 6 The figure shows the cyclic tensile stress-strain curve of the elastic gel prepared by Comparative Example 1 of this invention at a strain of 2000%. As can be seen from the figure, the nano-confined polymerization method significantly improves the elasticity of the gel, and the cyclic tensile stress-strain curve shows a hysteresis of less than 7%.

[0072] The crack propagation strain of the tear-resistant elastic gel prepared in Example 1 was found to be 5800%.

[0073] Figure 7 This is a stress-strain curve of the tear-resistant elastic gel prepared in Example 2 of the present invention. Compared with the method of preparing elastic gel without adding nano-confined materials in Comparative Example 1, the nano-confined polymerization method of adding molecular sieve SBA-15 in Example 2 significantly improves the mechanical properties of the gel, and the fracture strain is increased by more than 3 times.

[0074] Figure 8 The figure shows the cyclic tensile stress-strain curve of the tear-resistant elastic gel prepared in Example 2 of this invention at a strain of 6000%. As can be seen from the figure, the nano-confined polymerization method significantly improves the elasticity of the gel, and the cyclic tensile stress-strain curve shows a hysteresis of less than 7%.

[0075] The tear-resistant elastic gel (ionogel) prepared in Example 3 had a fracture strain of about 3000%, which is twice that of the fracture strain of the ionogel without the addition of TpPa-1 (about 1500%). The hysteresis curve of the cyclic tensile stress-strain curve was less than 7%, which proves that the nano-confined polymerization method is suitable for ionogels.

[0076] The tear-resistant elastic gel prepared in Example 4 had a fracture strain of about 10,000%, and the tear-resistant elastic gel prepared in Example 5 had a hysteresis of less than 10% in the cyclic tensile stress-strain curve, proving that the nano-confined polymerization method is suitable for organic gels.

[0077] In summary, this invention utilizes a photoinitiator to initiate the polymerization of monomer molecules and crosslinking agents within the confined space of a nano-confined material. The strong hydrogen bonding between interpenetrating polymer segments effectively immobilizes polymer chains that may slide under load, preventing energy dissipation. Simultaneously, the rigid nano-confined material prevents stress concentration at crack tips in the host material and significantly reduces the crack propagation sensitivity of the prepared gel, thereby improving the strength, strain, crack propagation resistance, and elasticity under ultimate deformation of the gel material, resulting in a tear-resistant elastic gel.

[0078] The above-described embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A method for preparing a tear-resistant elastic gel, characterized in that, Includes the following steps: A monomer molecule, a crosslinking agent, and a nano-confined material are added to a solvent, and a polymerization reaction is carried out under ultraviolet light irradiation in the presence of a photoinitiator to obtain the tear-resistant elastic gel. The monomer molecule is acrylamide; the nano-confined material is TpPa-1 or SBA-15, and the pore size of SBA-15 is 5 nm; the mass ratio of the nano-confined material to the monomer molecule is 1:(100~10000); the crosslinking agent is N,N-methylenebisacrylamide, polyethylene glycol diacrylate, pentaerythritol triacrylate, or pentaerythritol tetraacrylate; the mass ratio of the crosslinking agent to the monomer molecule is 1:(200~10000); the solvent is water, an ionic liquid, glycerol, or ethylene glycol; the mass ratio of the monomer molecule to the solvent is 1:(0.5~6).

2. The method according to claim 1, characterized in that, The mass ratio of the photoinitiator to the monomer molecule is 1:(50~1000).

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