CN110746614A - A kind of preparation method of impact-resistant high-strength physical hydrogel and application thereof - Google Patents

Abstract

The invention discloses a preparation method of high-strength physical hydrogel with impact resistance. The hydrogel prepared by the method has the properties of transparency, high modulus and compression resistance, and at the same time has the advantages of high stretchability, toughness, insensitivity to defects, self-healing, and flexible processability. The impact-resistant high-strength physical hydrogel provided by the present invention and the composite material containing the hydrogel can be applied to the fields of impact-resistant materials, textiles and sensors.

Description

A kind of preparation method of impact-resistant high-strength physical hydrogel and application thereof

technical field

The invention belongs to the technical field of polymer materials, and particularly relates to a preparation method and application of an impact-resistant high-strength physical hydrogel.

Background technique

Hydrogels are a class of polymer materials with a three-dimensional network structure containing a large amount of water. Due to the poor mechanical properties of traditional hydrogels (the tensile capacity is only several times the original length, and the fracture energy is less than 100J/m ^-2 ), its application as a structural material in the engineering field with high mechanical strength requirements is limited. . Therefore, hydrogel materials with unique excellent mechanical properties and tunable multifunctionality, which can be used as structural materials, have attracted much attention. Hydrogel materials with excellent properties have potential applications in various engineering fields, including soft machines, flexible electronics, communication engineering, and sensors. Studies have shown that the combined action of covalent and non-covalent bonds can be used to prepare high-strength hydrogels. In general, there are four main non-covalent interactions that are widely used to build high-strength hydrogels: hydrogen bonding, hydrophobic interactions, ionic electrostatic interactions, and van der Waals interactions. The introduction of non-covalent bonds can make high-strength gels with multifunctionality, such as high strength, toughness, self-healing, fatigue resistance, self-healing, etc. Although various types of hydrogels have been widely used in the biomedical field, they still have certain limitations as structural materials. When used as a structural material in production and living practice, hydrogels have shortcomings in mechanical properties, water retention capacity, transparency and versatility. The above-mentioned disadvantages limit the wide practical use of high-strength hydrogels as structural materials. In addition, in the fields of impact-resistant materials, textiles and sensors, there are no hydrogels with good impact resistance, high strength, high toughness, high tensile properties, and self-recovery, fatigue resistance, and self-healing properties at the same time. Applied literature reports.

SUMMARY OF THE INVENTION

In order to overcome the above-mentioned deficiencies of the prior art, the purpose of the present invention is to provide an impact-resistant high-strength physical hydrogel.

Another object of the present invention is to provide a method for preparing an impact-resistant high-strength physical hydrogel.

The third object of the present invention is to provide the application of an impact-resistant high-strength physical hydrogel in the fields of impact-resistant materials, textiles and sensors.

A fourth object of the present invention is to provide a composite material comprising an impact-resistant high-strength physico-physical hydrogel.

In order to achieve the above-mentioned first objective, the technical solution adopted in the present invention is to provide an impact-resistant high-strength physical hydrogel, the structure of which is to contain more than one polymerizable charged monomer and a neutral macromolecule polymerized It is a three-dimensional network formed by cross-linking of materials, wherein the three-dimensional network structure contains metal ions.

Wherein, the polymerizable charged monomer is selected from negatively charged monomers acrylic acid (AA), methacrylic acid (MAA), sodium styrene sulfonate (SSS), 2-acrylamido-2-methyl Propanesulfonic acid (AMPS), or positively charged monomers dimethylaminoethyl methacrylate methylammonium chloride (DMAEMA MC), dimethylaminoethyl acrylate methylammonium chloride (DMAEAA MC) , Diallyl Dimethyl Ammonium Chloride (DADMAC), Dimethyl Aminopropyl Acrylamide Methyl Ammonium Chloride (DMAPMA MC), Dimethyl Diallyl Ammonium Chloride (DMDAAC), Diallyl Diallyl-N-carbonylbutoxymethylammonium chloride (DACBMAC), diallylmethylbenzylammonium chloride (DAMABC), diallylethylbenzylammonium chloride (DAEABC), methacryloyl Oxyethyltrimethylammonium chloride (DMC), Acryloyloxyethyltrimethylammonium chloride (DAC), N,N-Dimethyl-N-benzyl-acryloyloxyammonium chloride (DBAAC ).

Wherein, the neutral high molecular polymer is selected from polyvinyl alcohol (PVA), polyethylene glycol (PEG), polyethylene oxide (PEO), hyperbranched polyglycidyl ether (HPG).

Wherein, the metal ion is selected from lithium ion, sodium ion, potassium ion, magnesium ion, aluminum ion, calcium ion or iron ion.

In order to achieve the above-mentioned second purpose, the technical scheme adopted in the present invention is to provide a preparation method of an impact-resistant high-strength physical hydrogel, the specific steps comprising: An initiator is added to the solution of the high molecular polymer, and the primary hydrogel is obtained by freezing and ablation after being placed for a certain period of time under the initiating conditions; (b) the primary hydrogel prepared in step a is immersed in a metal ion salt solution and reacted for a certain period of time Afterwards, an impact-resistant high-strength physical hydrogel is obtained.

Wherein, the charged monomer is selected from negatively charged monomers acrylic acid (AA), methacrylic acid (MAA), sodium styrene sulfonate (SSS), 2-acrylamido-2-methylpropanesulfonic acid Acid (AMPS), or positively charged monomers dimethylaminoethyl methacrylate methylammonium chloride (DMAEMA MC), dimethylaminoethyl acrylate methylammonium chloride (DMAEAA MC), diene propyl dimethyl ammonium chloride (DADMAC), dimethylaminopropyl acrylamide methyl ammonium chloride (DMAPMA MC), dimethyl diallyl ammonium chloride (DMDAAC), diallyl-N -Carboxylbutoxymethylammonium chloride (DACBMAC), diallylmethylbenzylammonium chloride (DAMABC), diallylethylbenzylammonium chloride (DAEABC), methacryloyloxyethyl Trimethylammonium chloride (DMC), acryloyloxyethyltrimethylammonium chloride (DAC), N,N-dimethyl-N-benzyl-acryloyloxyammonium chloride (DBAAC).

Wherein, the neutral high molecular polymer is selected from polyvinyl alcohol (PVA), polyethylene glycol (PEG), polyethylene oxide (PEO), hyperbranched polyglycidyl ether (HPG).

Preferably, the mass ratio of the charged monomer and the neutral polymer is 9:1 to 1:9.

Preferably, the total weight of the charged monomers and neutral high molecular polymers accounts for 1%-90% of the mass of the hydrogel.

Wherein, the initiation mode is photo initiation, thermal initiation or radiation initiation.

Preferably, the initiator is selected from α-ketoglutaric acid, ammonium persulfate, potassium persulfate, sodium persulfate, 2-hydroxy-2-methyl-1-phenylacetone, methyl benzoate or alkyl iodonium salts.

More preferably, the added amount of the initiator accounts for 0.01%-1% of the total weight of the hydrogel.

Preferably, the freezing time is 1 to 24 hours and the temperature is -80°C to 0°C.

Preferably, the ablation time is 1 to 12 hours, and the temperature is 10°C to 80°C.

Wherein, the metal ion is selected from lithium ion, sodium ion, potassium ion, magnesium ion, aluminum ion, calcium ion or iron ion.

Preferably, the concentration of the metal ion solution is 1-17 mol/L or a saturated salt solution.

Preferably, the ratio of the primary hydrogel to the concentration of metal ions is 1:20.

Preferably, the soaking time of the primary hydrogel in metal ion solutions of different concentrations is 1-12 hours.

Preferably, the pH of the soaking solution is 1-14.

Preferably, the soaking temperature is 20-40°C.

Lithium ion, sodium ion, potassium ion, magnesium ion, calcium ion or iron ion solution can be used as salting-out agent for preparing high strength hydrogel. The destructive effect of the salting-out agent on the hydration layer of the primary hydrogel mainly depends on the solvent effect of the cation. When the cation radius is smaller, the salinization effect is stronger, resulting in a more destructive hydration layer. In the present invention, a salt solution of lithium ions is preferred as the salting-out agent, which has a smaller radius and a larger ion potential. For the same anion, chloride salt is preferred as the salting-out agent. Because the solubility of chloride salt is higher than that of other anion salts at the same temperature, it meets the requirements of high concentration of salting agent, and it is convenient to compare a series of cation content to The effect of hydrogel properties. The effective salting-out effect will greatly improve the mechanical properties of the hydrogel, and increase the tensile strength, elastic modulus, self-recovery and transparency of the hydrogel material.

Therefore, the impact-resistant high-strength physical hydrogel can be adjusted by changing the ratio of polymerizable charged monomers to neutral high molecular polymers, the concentration of metal ions, and the soaking time to tune the mechanical properties of the hydrogel material.

In the impact-resistant high-strength physical hydrogel prepared by the above method, the rigid molecular chain formed by the polymerization of the charged monomer itself and the flexible polymer are cross-linked through non-covalent interaction, and the primary flexible polymer is first formed. The three-dimensional network structure of the hydrogel, and then the primary hydrogel was immersed in different concentrations of metal ion solutions. During this process, self-assembly and phase separation occur, and metal ions destroy the hydration layer of the charged polymer to produce a salting-out effect, that is, under high osmotic pressure, it shields electrostatic repulsion and promotes close proximity of polymer chains, thereby forming a dense Chain entanglement network structure with hydrogen bonds serving as cross-connection points. The dense charged network-like polymer chains are cross-linked by hydrogen bonds, which endow the hydrogel material with high stress and elasticity. The random distribution of sparse neutral polymers in the hydrogel network helps endow the material Large strain performance. At the same time, the breaking of weak hydrogen bonds and the deformation of flexible polymer chains can consume energy.

Therefore, the physical structure of the prepared impact-resistant high-strength physical hydrogel is closely related to its mechanical properties. For example, the ratio of charged monomer and neutral polymer, and the concentration of metal ions can be changed. and immersion time, etc., to adjust the mechanical properties of hydrogel materials.

The impact-resistant high-strength physical hydrogel prepared by the above method has high transparency and mechanical properties comparable to glass. Its toughness is as high as 54860J/m ² , its tensile strength is 13MPa (11 times elongation), its compressive strength is as high as 588MPa (85% strain at break), its tensile modulus is as high as 1.4MPa, and its compressive modulus is 1.47MPa. After repair, the fracture stress reached 1.82 MPa, and the mechanical properties were generally higher than that of most high-strength hydrogels, with recoverable hysteretic energy dissipation and self-healing ability. The strength and toughness of the impact-resistant high-strength physical hydrogel prepared by the invention are not only sufficient to resist steel balls fired from an air gun, but also have the properties of puncture resistance, self-healing, sutureability and crack insensitivity. This combination of excellent mechanical properties can be attributed to the synergistic effect of unique self-assembly, phase-separated structure, and high-density hydrogen bonding. Under the action of salting out, the dynamic cross-linking degree between high-density polymer chains formed by reversible hydrogen bonding and polymer chain entanglement increases to form a dense polymer network structure. In addition, since the metal ions in the hydrogel have certain hygroscopic properties, the impact-resistant high-strength physical hydrogel prepared by the present invention has good water storage capacity, and can maintain stable mechanical properties and long-term stability in air. Service time.

In order to achieve the above third objective, the technical solution adopted in the present invention is to apply the prepared impact-resistant high-strength physical hydrogel to impact-resistant materials, textiles and sensors.

Further, the impact-resistant material is bulletproof glass, anti-theft glass, special protective glass, tempered glass or its interlayer, bulletproof clothing, sports wrist guards, knee pads and other protective gear.

Further, the textile material is selected from flame retardant materials and fire clothes.

Further, the sensor material is selected from wearable devices, flexible robots, conductivity sensors, and shock-proof sensors.

In order to achieve the above fourth object, the present invention also provides a high-strength physical hydrogel composite material containing impact resistance. The composite material provided by the present invention also includes another material component with different chemical and physical properties.

Further, another material component contained in the composite material is silicon dioxide.

Compared with the prior art, the present invention has the advantages of adopting an impact-resistant high-strength physical hydrogel prepared by a simple process, environmentally friendly and non-toxic method, and on the one hand, greatly improving the production and preparation efficiency of the hydrogel. At the same time, the cost of raw materials is low, no complicated modification treatment is required, and the preparation process is green and safe. performance, and at the same time has the advantages of high stretchability, high toughness, high recovery defect insensitivity, and self-healing. The impact-resistant high-strength physical hydrogel provided by the present invention and the composite material containing the hydrogel can be applied to the fields of impact-resistant materials, textiles and sensors.

Description of drawings

Figure 1 shows the tensile stress-strain curves of hydrogels containing metal ions of different valences.

Figure 2 shows the tensile stress-strain curves of hydrogels soaked in lithium chloride solution for different times.

Figure 3 shows the tensile stress-strain curves of hydrogels soaked in different concentrations of lithium chloride solutions.

Figure 4 shows the tensile stress-strain curves of hydrogels with different ratios of charged monomers and neutral polymers.

Figure 5 is a tensile stress-strain curve of hydrogels containing different ratios of initiator content.

Figure 6 is a tensile stress-strain curve of hydrogels containing different proportions of silica.

Figure 7 shows the fracture energies of hydrogels soaked in lithium chloride solutions of different concentrations.

Figure 8 is a tensile stress-strain curve of the time recovery properties of impact resistant high strength physical hydrogels.

Figure 9 is a tensile stress-strain curve of the self-healing properties of an impact-resistant high-strength physical hydrogel.

Figure 10 is a compressive stress-strain curve of hydrogels with different ratios of charged monomers and neutral polymers.

Figure 11 is a graph showing the water retention versus time of the impact-resistant high-strength physical hydrogel at 25°C and 30% humidity.

Figure 12 is a graph of the transparency versus wavelength of an impact-resistant high-strength physical hydrogel.

Figure 13 is a scanning electron microscope (SEM) photograph of the impact-resistant high-strength physical hydrogel.

Figure 14 is an atomic force microscope-infrared (Atomic forcemicroscopy (AFM) with an infrared capability (IR), AFM-IR) image of an impact-resistant high-strength physical hydrogel.

Figure 15 is a graph (Atomic force microscopy (AFM) with an infrared (IR), AFM-IR) of hydrogels without and with added metal ions.

Figure 16 Schematic diagram of the preparation process of impact-resistant high-strength physical hydrogel

Detailed ways

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples.

Example 1

This example includes the following steps: Step 1: First, dissolve 3 g of hyperbranched polyglycidyl ether (HPG) powder in 70 mL of deionized water at 90°C in a water bath, and then add 7 g of methacryloyloxyethyltrimethyl Ammonium chloride (DMC), 0.135g α-ketoglutaric acid, dissolve uniformly at room temperature of 37°C. The mass ratio of 3 g of hyperbranched polyglycidyl ether (HPG) to methacryloyloxyethyltrimethylammonium chloride is 3:7, and deionized water accounts for 80% of the total mass of the mixed solution. Pour the prepared solution into a glass mold, let it stand for 12 hours at room temperature to completely defoam, and then place it under a UV lamp for 6 hours. Finally, the material was frozen at -20°C for 2 hours, and then ablated at room temperature for 3 hours.

The second step: in a 100mL volumetric flask, dissolve 54.868g LiCl in deionized water to obtain a LiCl salt solution with a concentration of 12mol/L.

The third step: the hydrogel prepared in the first step is completely immersed in the LiCl salt solution with a concentration of 12 mol/L prepared in the second step, and after standing at room temperature for 12 hours, an impact-resistant high-strength physical water is obtained gel. The specific preparation process and principle are shown in Figure 16.

Tensile and compressive tests were carried out on the dumbbell-shaped hydrogel obtained with an electronic tensile machine. When the concentration of LiCl salt solution was 12 mol/L, the obtained super-strong and super-tough physical hydrogel could be stretched to 10 times its original length and fractured after stretching. The strength reaches 13MPa, the fracture energy is 54860J/m ² and the fracture stress reaches 1.82MPa after self-healing. The hydrogel gel exhibited an average transmittance of 90% in visible light wavelengths from 380 to 720 nm measured by UV spectrophotometer. Under the environment of room temperature 25℃ and 30% humidity, the water retention capacity of the gel is at least 100h.

Example 2

This example includes the following steps: the first step, first, under the condition of a water bath at 90 °C, dissolve 15 g of polyvinyl alcohol in 70 mL of deionized water, then add 5 g of diallyl methyl benzyl ammonium chloride, and at room temperature at 37 ° C Dissolve evenly. The mass ratio of polyvinyl alcohol powder and diallyl methyl benzyl ammonium chloride is 3:1, deionized water accounts for 30% of the total mass of the mixed solution, and the addition amount of initiator alkyl iodonium salt accounts for the amount of hydrogel. 0.05% of the total weight of the glue. Pour the prepared solution into a glass mold, let it stand for 12 hours at room temperature to completely defoam, and then place it under a UV lamp for 6 hours. Finally, the material was frozen at -70°C for 2 hours, and then ablated at 60°C for 5 hours.

The second step: in a 100mL volumetric flask, prepare a MgCl ₂ salt solution with a concentration of 5mol/L.

The third step: completely soak the hydrogel prepared in the first step in the MgCl ₂ salt solution with a concentration of 5 mol/L prepared in the second step. An impact-resistant high-strength physical hydrogel is formed.

Example 3

This example includes the following steps: the first step is to dissolve 12g of polyethylene glycol powder in 70mL of deionized water under a water bath condition of 90°C, then add 2g of sodium styrene sulfonate, and dissolve uniformly at room temperature of 37°C. The mass ratio of polyvinyl alcohol powder and sodium styrene sulfonate is 6:1, deionized water accounts for 20% of the total mass of the mixed solution, and the addition amount of initiator ammonium persulfate accounts for 0.05% of the total weight of the hydrogel. Pour the prepared solution into a glass mold and let it stand for 12 hours at room temperature after the defoaming is complete. Finally, the material was frozen at -25°C for 8h, and then ablated at 40°C for 7h.

The second step: in a 100mL volumetric flask, prepare an AlCl ₃ salt solution with a concentration of 17mol/L.

The _third step: completely soak the hydrogel prepared in the first step in the AlCl salt solution with a concentration of 17 mol/L prepared in the second step, the pH of the soaking solution is 9, the soaking temperature is 60 °C, and after soaking for 3 hours, An impact-resistant high-strength physical hydrogel is formed.

Example 4

This example includes the following steps: the first step is to dissolve 3 g of polyethylene oxide powder in 70 mL of deionized water under the condition of a water bath at 90 °C, and then add 18 g of dimethylaminoethyl acrylate methyl ammonium chloride, and the room temperature is 37 °C. Dissolve uniformly under conditions. The mass ratio of polyvinyl alcohol powder to dimethylaminoethyl acrylate methyl ammonium chloride is 1:6, deionized water accounts for 80% of the total mass of the mixed solution, and the addition amount of initiator sodium persulfate accounts for the total amount of hydrogel. 0.5% by weight. Pour the prepared solution into a glass mold and let it stand for 12 hours at room temperature after the defoaming is complete. Finally, the material was frozen at -50 °C for 5 h, and then ablated at 80 °C for 1 h.

The second step: in a 100mL volumetric flask, prepare a FeCl3 salt solution with a concentration _of 3mol/L.

The third step: completely soak the hydrogel prepared in the first step in the FeCl salt solution with a concentration of ₃ mol/L prepared in the second step. The pH of the soaking solution is 7, and the soaking temperature is 30 °C. An impact-resistant high-strength physical hydrogel is formed.

Example 5

Steel marble impact test

The impact-resistant high-strength physical hydrogel prepared in Example 1 was used to conduct a steel ball impact test, and the speed of the steel ball (diameter 10mm, mass 4.1g) was controlled by the pressure in the air chamber, and was set to 150m/s, 170m /s, 200m/s, and then use a laser velocimeter to measure the specific initial velocity and residual velocity of the steel marble. In order to record the whole process of the deformation of the target material, two high-speed cameras are set behind the target material. The energy absorbed by the target material is energy dissipation (Ep). The energy dissipation of the target material (100×100×2mm) affects the kinetic energy change of the steel ball (diameter 10mm, 4.1g). The following is the introduction of the test standard ballistic performance: People generally It is believed that energy is conserved, and the kinetic energy lost by the steel ball is equal to the dissipated energy of the sample. The energy dissipation (Ep) of the sample can be calculated by the following formula:

Wherein _Vi = 147.35m/s is the ball incident velocity, V _r =2.89m/s is the residual velocity of the steel ball, m = 4.1g is the mass of the steel ball, respectively the mass of the sample. The kinetic energy lost by the steel ball is equal to the energy dissipation (E _p ) of the hydrogel, which is as high as 1.54 J/g per unit mass of the hydrogel.

Example 6

Figure 1 shows the tensile stress-strain curves of impact-resistant high-strength physical hydrogels prepared in different valence ion salting-out agents. It can be seen that lithium salts have the strongest ability to form super-strong and super-tough gels. effect. This is largely related to the solvation power and ion size of metal salt ions, with Li ⁺ ions having the highest solvation power (-3.01) and the smallest radius (176pm). In contrast, other ions have lower solvation power (-2.71Na ⁺ , -2.92K ⁺ , -2.37Mg ²⁺ , -2.87Ca ^{2 +} ) and larger ionic radii (102Na ⁺ , 138K ⁺ , 72Mg ^{2 +} , and 100pm Ca ²⁺ ). In general, metal salt ions with a small ionic radius and monovalent charge can better promote the diffusion in the interstitial space of salt ion polymer molecules and reduce the obstacles of electrostatic interaction; on the other hand, metal ions with higher solvation can be removed from the hydrogel extract more free water molecules.

Example 7

Figure 2 tested the mechanical properties of the impact-resistant high-strength physical hydrogels with different soaking times during the preparation process. It was found that adjusting the soaking time could adjust the mechanical properties of the hydrogels. Taking the PVA/PAA (soft hydrogel) soaked in LiCl solution with a concentration of 12 mol/L as an example, when the soaking time was extended from 0 h to 24 h, the mechanical properties changed significantly. The fracture stress increased from 75±2.36kPa to 13±1.8MPa.

Example 8

The mechanical properties of the impact-resistant high-strength physical hydrogels prepared by soaking with different concentrations of LiCl salts were tested. The PAA hydrogel (82 kPa) is 160 times higher. The toughness increased from 0.89 ± 0.02 MJ/m ³ (PVA/PAA hydrogel) to 48.97 ± 5.52 MJ/m ³ (Gel-12M hydrogel).

Example 9

The mechanical properties of the impact-resistant high-strength physical hydrogels prepared with different ratios of PVA and PAA are tested. Figure 4 shows that the PVA/PAA-LiCl hydrogels are compared with PAA-LiCl and PVA-LiCl hydrogels. , the PVA/PAA-LiCl hydrogel prepared with a ratio of PVA and PAA of 1:9 exhibited more significant mechanical properties.

Example 10

It can be seen from Figure 5 that the mechanical properties of the PVA/PAA-LiCl hydrogels prepared with initiator contents of 0.05 wt%, 0.1 wt% and 0.5 wt%, respectively, are relatively high. Especially when the initiator content is 0.5wt%, the mechanical properties of the PVA/PAA-LiCl hydrogel are improved most obviously.

Example 11

In order to improve the energy consumption of impact-resistant high-strength physical hydrogels and meet the needs in the field of bulletproofing, the gel composites _were prepared by dispersing SiO nanoparticles (30 nm) in different proportions into the polymer network. Figure 6 shows that when the content of nano-SiO ₂ is 3%, the tensile strength of the composite hydrogel material reaches 30.0 MPa, the tensile length reaches 8 times the original, and the corresponding energy dissipation is 102 MJ/m ³ .

Example 12

In order to study the fracture energy of impact-resistant high-strength physical hydrogels, the fracture energy of the gels immersed in different concentrations of LiCl salt solution was characterized. It can be seen from Fig. 7 that the PVA/PAA-LiCl gel soaked in LiCl solution with a concentration of 12 mol/L has an ultra-high fracture energy of 54860 J/m ² .

Example 13

The tensile stress-strain test results of the recovery performance of the impact-resistant high-strength physical hydrogel are shown in Figure 8. The recovery behavior of the stretched hydrogels was further tested after different relaxation times. The second test started after 30 minutes and the sample almost returned to its original tensile stress.

Example 14

The tensile stress-strain test results of the self-healing properties of the impact-resistant high-strength physical hydrogel are shown in Figure 9. Since hydrogen bond break repair is reversible, the impact-resistant high-strength physical hydrogel cut in half can self-heal and resist loading after self-healing. The two broken gels were reassembled at room temperature, and self-healing was not easy, most likely because the high stiffness of the material hindered the mobility of the polymer chains. However, after heating the two fragments at 60°C for 8 h, they could heal together to form a whole, and were able to maintain a considerable bearing capacity. When the self-healing impact-resistant high-strength physical hydrogel is loaded to fracture, the fracture stress reaches 1.82 MPa.

Example 15

The compressive stress-strain results of the impact-resistant high-strength physical hydrogels prepared by soaking different proportions of PVA and PAA in LiCl salt solution are shown in Figure 10. The compressive modulus of the high-strength gel reaches the MPa level, and as the proportion of PAA increases As it increases, the modulus also increases.

Example 16

It can be seen from Figure 11 that under the conditions of temperature of 25 °C and relative humidity of 30%, the impact-resistant high-strength physical hydrogel prepared by PVA/PAA will lose water quickly and its quality will decrease rapidly. However, the PVA/PAA-LiCl hydrogel samples maintained relatively stable quality. The mass ratio (W/W ₀ ) of the hydrogel in the process of water loss was calculated, the mass at time=n was recorded by an electronic balance, and its water retention efficiency was calculated.

W/W ₀ =Mass(hydrogel, time=n)/Mass(hydrogel, time=0),

Mass (hydrogel, time=0) is calculated from the mass of the starting material used. In hydrogels, water molecules bound to ions must break chemical bonds to evaporate, while free water molecules evaporate naturally.

Example 17

The transparency test of the impact-resistant high-strength physical hydrogel is shown in Figure 12. The 2mm thick PVA/PAA soft film was immersed in the solution to shrink the soft film and gradually become more transparent, forming a 1.5mm thick film. PVA/PAA-LiCl films. It can be seen that the transmittance (T) of the PVA/PAA-LiCl gel is as high as 90% from 380 nm to 720 nm, which is significantly higher than that of the PVA/PAA hydrogel sample (83%).

Example 19

The scanning electron microscope test of the impact-resistant high-strength physical hydrogel prepared by the present invention shows the result as shown in Figure 13. The surface of the gel forms a branch-like structure. Combined with the test results of infrared-atomic force microscopy, as shown in Figure 14, it can be seen that The impacted high-strength physical hydrogel has a phase-separated structure.

As shown in Figure 15, Atomic Force Microscopy (AFM) with infrared (IR) capability clearly distinguishes the two samples. In particular, the topography images of the hydrogels with the addition of metal ions (Panel B) correspond well with those of the trunk branching structures observed from SEM, indicating that PAA (-COOH groups, white) and PVA (-OH groups, black) non-homogeneous mixing. In contrast, those images of hydrogels without added metal ions showed no significant difference (Panel A), which indicated that PAA (-COOH groups, white) and PVA (-OH groups, black) were homogeneously mixed. Additional evidence was found in the IR spectrum, where the carbonyl group (C=O) of PAA in the hydrogel without added metal ions showed two strong vibrations (Panel C), one at 1750 cm ^-1 and the other at 1680 cm ^-1 , PAA in PAA-rich region and PAA in PVA-rich environment, respectively.

The above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that the foregoing embodiments can still be used for The technical solutions described in the examples are modified, or some or all of the technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. An impact-resistant high-strength physical hydrogel, the structure of which is a three-dimensional network formed by mutual crosslinking of a polymerizable charged monomer and a neutral high-molecular polymer, and the three-dimensional network structure contains metal ions.

2. The impact-resistant, high-strength physical hydrogel of claim 1, wherein said polymerizable charged monomer is selected from the group consisting of negatively charged monomers Acrylic Acid (AA), methacrylic acid (MAA), Sodium Styrene Sulfonate (SSS), 2-acrylamido-2-methylpropanesulfonic Acid (AMPS), and positively charged monomers dimethylaminoethylmethylammonium methacrylate (DMAEMA-MC), dimethylaminoethylmethylacrylate (DMAEAA-MC), diallyldimethylammonium chloride (DADMAC), dimethylaminopropylacrylamidomethylammonium chloride (DMAPMA-MC), dimethyldiallylammonium chloride (DMDAAC), diallyl-N-carboxybutoxymethylammonium chloride (DACBMAC), diallylmethylammonium chloride (DAMABC), diallylethylbenzylammonium chloride (DAEABC), methacryloyloxyethyltrimethylammonium chloride (DMC), Acryloyloxyethyltrimethylammonium Chloride (DAC), N-dimethyl-N-benzyl-acryloyloxyammonium chloride (DBAAC).

3. The impact-resistant, high-strength physical hydrogel of claim 1, wherein said neutral polymer is selected from the group consisting of polyvinyl alcohol (PVA), polyethylene glycol (PEG), polyethylene oxide (PEO), and hyperbranched polyglycidyl ether (HPG), and said metal ion is selected from the group consisting of lithium ion, sodium ion, potassium ion, magnesium ion, aluminum ion, calcium ion, and iron ion.

4. A method for preparing an impact-resistant, high-strength physical hydrogel, comprising the steps of:

(a) firstly, adding an initiator into a solution containing charged monomers and neutral high molecular polymers, standing under an initiation condition, and freezing and melting to obtain primary hydrogel; (b) and (b) immersing the primary hydrogel obtained in the step a into a metal ion salt solution, and reacting to obtain the impact-resistant high-strength physical hydrogel.

5. The method for preparing an impact-resistant high-strength physical hydrogel according to claim 5, wherein the mass ratio of the charged monomer to the neutral high-molecular polymer is 9: 1-1: 9.

6. The method of claim 5, wherein the initiation is photoinitiated, thermally initiated, or radiation initiated.

7. The method of claim 5, wherein the metal ions are lithium, sodium, potassium, magnesium, aluminum, calcium, or iron ions; the metal ion concentration is 1-17mol/L or saturated salt solution, and the primary hydrogel is soaked in the metal ion solution for 1-24 hours.

8. A composite comprising the impact-resistant, high-strength physical hydrogel of claim 1.

9. Composite material according to claim 8, characterized in that another material component comprised is silica.

10. Use of the impact resistant high strength physical hydrogel of claim 1 in impact resistant materials, textiles and sensors.

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