Tough and fatigue-resistant hydrogels for cushioning impacts, methods of making, and uses thereof

Abstract

The application discloses a kind of tough fatigue-resistant hydrogel for buffering impact and preparation method, belong to novel soft material field.The application is based on the energy dissipation design of combined long-chain linear polymer preparation strategy and solvent space restriction strategy, by increasing the content of acrylamide monomer in precursor liquid, and using the strong water-binding ability of hydrophilic salt calcium chloride, a long-chain high polymer hydrogel without crosslinking point is prepared.The hydrogel prepared by the application is a linear hydrogel with strong toughness and fatigue resistance.The chains in linear hydrogel are more easily entangled, have higher interchain interaction, can effectively improve the fracture toughness, fatigue threshold and energy absorption of hydrogel, and can be widely used as high-performance damping material.

Description

[0001] This application is a divisional application of the invention patent with application number 202410988197.8, application date July 23, 2024, and invention title "A tough and fatigue-resistant hydrogel for cushioning impact and its preparation method". Technical Field

[0002] This invention belongs to the field of novel soft materials, specifically relating to a tough and fatigue-resistant hydrogel for shock absorption and its preparation method. Background Technology

[0003] Damping materials, due to their effectiveness in absorbing energy and reducing vibration, play a significant role in reducing noise, vibration, and shock. These materials serve a crucial role in industries such as aerospace, automotive manufacturing, military, and electronics. Applications include impact-resistant layers for micro-aircraft, sound insulation layers for automotive bodies, damping adhesives for microelectronic devices, protective soft armor, and robot joint buffers; these fields have an urgent need for high-performance damping materials. While traditional damping materials, such as rubber, metals, and their composites, can meet basic requirements, they often struggle to meet higher performance demands due to low loss factors, insufficient durability, and high load requirements.

[0004] Hydrogels, as unique soft materials, have shown great potential in the field of damping materials due to their excellent viscoelasticity and high water content. These materials can not only effectively dissipate energy but also possess good biocompatibility and adaptability to changing environments. Nevertheless, the damping properties of most traditional hydrogels still need to be improved, and enhancing their strength, toughness, and fatigue resistance are currently the main research directions.

[0005] Currently, research on damping hydrogels is still in its early stages. Inspired by spider footpads, Park et al. developed a viscoelastic gelatin-chitosan hydrogel damper (Park B, Shin JH, Ok J, et al. Cuticular pad–inspired selective frequency damper for nearly dynamic noise–free bioelectronics[J]. Science, 2022, 376(6593):624-629.). This damper can dissociate the viscous bonds in the polymer matrix under the stimulation of external vibration and rearrange the chitosan and gelatin chains to achieve frequency damping, effectively shielding noise below 30Hz. However, under high-frequency vibration and impact, its energy absorption effect is poor, and the displacement response during impact is large and the vibration duration is long. At the same time, the modulus of this damper is low (less than 10 kPa), which is insufficient to adapt to complex environments.

[0006] On the other hand, Yuan et al. prepared chitin hydrogels using a binary solvent-induced self-assembly method. This method first promotes the formation of primary layered fibers through pre-evaporation, followed by binary solvent exchange to construct a two-dimensional layered microstructure, forming a multilayered structure of nanocrystals (Yuan F, Zhang XX, Wu K, et al. Damping chitin hydrogels by harnessing insect-cuticle-inspired hierarchical structures[J]. Cell Reports Physical Science, 2023, 4(11).). This structure achieves a certain degree of barrier and flexibility. However, it still cannot effectively buffer impacts; in the falling ball impact experiment, obvious rebound displacement can still be observed, indicating that its energy absorption effect needs further improvement. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing hydrogel damping materials in effectively absorbing energy under high-frequency vibration and impact, and in being unable to simultaneously achieve excellent strength and stability. The invention provides a strong and fatigue-resistant hydrogel for buffering impacts and its preparation method.

[0008] The specific technical solution adopted in this invention is as follows:

[0009] In a first aspect, the present invention provides a method for preparing a strong and fatigue-resistant hydrogel for shock absorption, comprising:

[0010] S1. Using water as a solvent, add acrylamide, calcium chloride and initiator, mix thoroughly to prepare a precursor solution, wherein the mass ratio of acrylamide to water is (1~2):1, and the mass ratio of calcium chloride to water is (0~2 / 3):1.

[0011] S2. Place the precursor liquid in a transparent mold and irradiate it with ultraviolet light in a vacuum environment for 1 to 3 hours to obtain a strong and fatigue-resistant hydrogel.

[0012] As a preferred embodiment of the first aspect above, when preparing the precursor solution, the mass ratio of calcium chloride to water is (0.25 to 2 / 3):1.

[0013] As a preferred embodiment of the first aspect above, when preparing the precursor solution, the mass ratio of acrylamide to water is 1:1, and the mass ratio of calcium chloride to water is 2 / 3:1.

[0014] As a preferred embodiment of the first aspect above, the ultraviolet wavelength used for the ultraviolet irradiation is 360–370 nm, and the power is 35–45 W.

[0015] Furthermore, the ultraviolet irradiation uses an ultraviolet wavelength of 365nm, a power of 40W, and an irradiation duration of 3 hours.

[0016] As a preferred embodiment of the first aspect above, the initiator is photoinitiator 2959.

[0017] Furthermore, when preparing the precursor solution, the mass ratio of the initiator to the monomer is (0.0005~0.01):1.

[0018] Furthermore, when preparing the precursor solution, the mass ratio of the initiator to the monomer is 0.001:1.

[0019] In a second aspect, the present invention provides a tough and fatigue-resistant hydrogel for shock absorption prepared by the preparation method described in any of the embodiments of the first aspect above.

[0020] Thirdly, the present invention provides an application of the tough, fatigue-resistant hydrogel for shock absorption as described in the second aspect above as a damping material.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] In the design of the damping hydrogel, this invention employs a linear polymer system, avoiding the storage of elastic potential energy in the cross-linked network during impact. Furthermore, this invention utilizes the strong water-binding ability of the hydrophilic salt calcium chloride to introduce high spatial confinement between polymer chains, enhancing the interaction between chains and thus improving the damping effect.

[0023] The robust and fatigue-resistant hydrogel prepared by this invention exhibits superior mechanical properties compared to existing damping materials, including high damping value, high modulus, high fracture strength, high toughness, and high fatigue threshold. Under high-frequency impact, this robust and fatigue-resistant hydrogel can absorb impact energy to a great extent, while exhibiting minimal peak amplification effect and displacement response, reducing post-impact recovery time. Due to its high energy absorption, impact blocking can be achieved with a small fabrication volume. Furthermore, complex structures can be designed using 3D printing, which can improve drag reduction efficiency, reduce material consumption, lower costs, and adapt to complex environments in engineering applications. Attached Figure Description

[0024] Figure 1 The figures show tensile diagrams and modulus and strength test results of different hydrogels in the embodiments of the present invention.

[0025] Figure 2 The figures show the tensile test results of different hydrogels in the embodiments of the present invention;

[0026] Figure 3 The figure shows the fracture toughness test results of different hydrogels in the embodiments of the present invention;

[0027] Figure 4 The graph shows the dissipation test results of different hydrogels in the embodiments of the present invention;

[0028] Figure 5 This is a fatigue threshold diagram of a highly space-confined linear hydrogel in an embodiment of the present invention;

[0029] Figure 6 The figures show the results of rheological frequency sweep and stress relaxation experiments on different hydrogels in the embodiments of the present invention.

[0030] Figure 7 The figure shows the results of the ball impact test of different hydrogels in the embodiments of the present invention. Detailed Implementation

[0031] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. Technical features in the various embodiments of the present invention can be combined accordingly without mutual conflict.

[0032] Existing hydrogel dampers can effectively block low-frequency noise, but they cannot effectively absorb energy when faced with high-frequency vibrations and impacts. Furthermore, existing dampers cannot simultaneously achieve excellent strength and stability. Therefore, this invention provides a strong, tough, and fatigue-resistant hydrogel for shock absorption and its preparation method. Through an energy dissipation design combining a long-chain linear polymer preparation strategy and a solvent space confinement strategy, a high-damping hydrogel material is prepared. This material exhibits low peak amplification and low displacement and time response, possessing both high damping coefficient and high toughness and fatigue resistance. The specific preparation method of this strong, tough, and fatigue-resistant hydrogel for shock absorption is as follows:

[0033] S1. Using water as a solvent, add acrylamide (AAm), calcium chloride (CaCl2) and an initiator, and mix thoroughly to prepare a precursor solution, wherein the mass ratio of acrylamide to water is (1-2):1, and the mass ratio of calcium chloride to water is (0-2 / 3):1.

[0034] S2. Place the above precursor liquid in a transparent mold and irradiate it with ultraviolet light in a vacuum environment for 1 to 3 hours to obtain a strong and fatigue-resistant hydrogel.

[0035] Unlike conventional preparations of hydrogels with three-dimensional cross-linked networks, the preparation method of this invention increases the content of acrylamide monomer in the precursor solution, specifically controlling the mass ratio of AAM monomer to water within the range of 1:1 to 2:1, and simultaneously adds an initiator followed by vacuum ultraviolet irradiation, thus obtaining a long-chain polymer hydrogel without cross-linking points. The hydrogel prepared by this invention is a linear hydrogel with strong and fatigue-resistant properties. In linear hydrogels, chains are more easily entangled, exhibiting higher inter-chain interactions, which can effectively improve the fracture toughness, fatigue threshold, and energy absorption of the hydrogel.

[0036] In the above-mentioned hydrogel preparation method, the ratio of each component and the selection of the initiator can be optimized according to actual conditions.

[0037] It should be noted that calcium chloride is not a necessary component in the precursor solution, and its content can be zero. Controlling the calcium chloride content can affect the spatial confinement linearity of the final hydrogel; the higher the calcium chloride content, the greater the spatial confinement, and with increased spatial confinement, both the modulus and tensile strength of the hydrogel improve. Preferably, when preparing the precursor solution, the mass ratio of calcium chloride to water is (0.25 to 2 / 3):1. When the mass ratio of calcium chloride to water reaches two-thirds to one (2 / 3:1), the mass fraction of calcium chloride essentially reaches its upper solubility limit, i.e., a mass fraction of 40%.

[0038] Furthermore, the content of acrylamide and calcium chloride needs to be optimized when preparing the above-mentioned precursor solution. Preferably, the mass ratio of acrylamide to water is 1:1, and the mass ratio of calcium chloride to water is 2 / 3:1.

[0039] The type of initiator used in this invention can be optimized according to actual needs. Initiator types may include photoinitiator 2959, lithium phenyl (2,4,6-trimethylbenzoyl) phosphate (LAP), 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), α-ketoglutaric acid, benzoyl peroxide, etc. Preferably, photoinitiator 2959 is used. When using it, a 2959-ethanol solution can be prepared using ethanol as a solvent and added to the precursor solution. The amount of initiator used in preparing the driving solution can be determined through gradient optimization. Preferably, the mass ratio of initiator to monomer is (0.0005~0.01):1, more preferably 0.001:1.

[0040] It should also be noted that when placing the aforementioned precursor solution in a transparent mold, it is necessary to maintain the precursor solution under vacuum before ultraviolet irradiation to avoid contact with air. The simplest way to maintain a vacuum environment is to fill the inner cavity of the transparent mold with the precursor solution. Of course, if the inner cavity is not completely filled, the excess air can be evacuated and then sealed to maintain a vacuum state, which will also meet the requirements.

[0041] The aforementioned precursor solution can be placed in an ultraviolet curing chamber for ultraviolet irradiation for 1 to 3 hours to obtain a strong and fatigue-resistant hydrogel. Preferably, the ultraviolet wavelength used for ultraviolet irradiation is 360–370 nm, and the power is 35–45 W; more preferably, the ultraviolet wavelength is 365 nm, the power is 40 W, and the irradiation time is 3 hours.

[0042] The strong and fatigue-resistant hydrogel prepared by the above-described preparation method of the present invention can be used as a damping material to manufacture various devices, such as hydrogel dampers. Moreover, due to the high energy absorption of this type of material, impact blocking can be achieved with a small fabrication volume, and more complex structures can be designed through 3D printing to realize various functions.

[0043] The following examples illustrate the specific preparation method of the above-mentioned strong and fatigue-resistant hydrogel, demonstrating its technical effects.

[0044] Example 1

[0045] 5g of acrylamide (AAM) was dissolved in 5ml of deionized water, and 0.25ml of 0.1mol / L 2959-ethanol solution was added. After thorough stirring and shaking, a precursor solution was formed. In this precursor solution, the components were proportioned as follows: the mass ratio of AAM to water was 1:1, and the mass ratio of photoinitiator 2959 to AAM was 1:1000. The precursor solution was then poured into a sealed acrylic mold, filling the mold cavity to create a vacuum environment. The entire mold was then placed in a UV curing chamber with a wavelength of 365nm and a power of 40W and irradiated with UV light for 3 hours to obtain a strong, fatigue-resistant hydrogel, denoted as PAAm-L space-confined linear hydrogel.

[0046] Example 2

[0047] 5g of acrylamide (AAM) and 0.56g of CaCl2 were dissolved in 5ml of deionized water, and 0.25ml of 0.1mol / L 2959-ethanol solution was added. After thorough stirring and shaking, a precursor solution was formed. In this precursor solution, the components were proportioned as follows: AAM to water was 1:1, calcium chloride to water was approximately 1:9 (10% by mass), and photoinitiator 2959 to AAM was 1:1000. The precursor solution was then poured into a sealed acrylic mold, filling the mold cavity to create a vacuum environment. The entire mold was then placed in a UV curing chamber with a wavelength of 365nm and a power of 40W for 3 hours of UV irradiation, resulting in a strong, fatigue-resistant hydrogel, denoted as PAAm-10 spatially confined linear hydrogel.

[0048] Example 3

[0049] 5g of acrylamide (AAM) and 1.25g of CaCl2 were dissolved in 5ml of deionized water, and 0.25ml of 0.1mol / L 2959-ethanol solution was added. After thorough stirring and shaking, a precursor solution was formed. In this precursor solution, the relative proportions of the components were calculated as follows: the mass ratio of AAM to water was 1:1, the mass ratio of calcium chloride to water was approximately 0.25:1 (20% by mass), and the mass ratio of photoinitiator 2959 to AAM was 1:1000. The precursor solution was then poured into a sealed acrylic mold, filling the mold cavity to create a vacuum environment. The entire mold was then placed in a UV curing chamber with a wavelength of 365nm and a power of 40W and irradiated with UV light for 3 hours to obtain a strong, fatigue-resistant hydrogel, denoted as PAAm-20 spatially confined linear hydrogel.

[0050] Example 4

[0051] 5g of acrylamide (AAM) and 3.33g of CaCl2 were dissolved in 5ml of deionized water, and 0.25ml of 0.1mol / L 2959-ethanol solution was added. After thorough stirring and shaking, a precursor solution was formed. In this precursor solution, the components were proportioned as follows: AAM to water was 1:1, calcium chloride to water was approximately 2:3 (40% by mass), and photoinitiator 2959 to AAM was 1:1000. The precursor solution was then poured into a sealed acrylic mold, filling the mold cavity to create a vacuum environment. The entire mold was then placed in a UV curing chamber with a wavelength of 365nm and a power of 40W for 3 hours of UV irradiation to obtain a strong, fatigue-resistant hydrogel, denoted as PAAm-H spatially confined linear hydrogel.

[0052] Example 5

[0053] 2.5g of acrylamide (AAM) and 6.66g of CaCl2 were dissolved in 10ml of deionized water, and 0.125ml of 0.1mol / L 2959-ethanol solution was added. After thorough stirring and shaking, a precursor solution was formed. In this precursor solution, the relative proportions of the components were calculated as follows: the mass ratio of AAM to water was 0.25:1, the mass ratio of calcium chloride to water was approximately 2:3 (40% by mass percentage), and the mass ratio of photoinitiator 2959 to AAM was 1:1000. The precursor solution was then poured into a sealed acrylic mold, filling the mold cavity to create a vacuum environment. The entire mold was then placed in a UV curing chamber with a wavelength of 365nm and a power of 40W and irradiated with UV light for 3 hours to obtain a strong, fatigue-resistant hydrogel, denoted as 0.25:1 PAAm-H space-confined linear hydrogel.

[0054] Example 6

[0055] 5g of acrylamide (AAM) and 6.66g of CaCl2 were dissolved in 10ml of deionized water, and 0.25ml of 0.1mol / L 2959-ethanol solution was added. After thorough stirring and shaking, a precursor solution was formed. In this precursor solution, the relative proportions of the components were calculated as follows: the mass ratio of AAM to water was 0.25:1, the mass ratio of calcium chloride to water was approximately 2:3 (40% by mass percentage), and the mass ratio of photoinitiator 2959 to AAM was 1:1000. The precursor solution was then poured into a sealed acrylic mold, filling the mold cavity to create a vacuum environment. The entire mold was then placed in a UV curing chamber with a UV wavelength of 365nm and a power of 40W and irradiated with UV light for 3 hours to obtain a strong, fatigue-resistant hydrogel, denoted as 0.5:1 PAAm-H space-confined linear hydrogel.

[0056] Example 7

[0057] 20g of acrylamide (AAM) and 6.66g of CaCl2 were dissolved in 10ml of deionized water, and 1ml of 0.1mol / L 2959-ethanol solution was added. After thorough stirring and shaking, a precursor solution was formed. In this precursor solution, the relative proportions of the components were calculated as follows: the mass ratio of AAM to water was 0.25:1, the mass ratio of calcium chloride to water was approximately 2:3 (40% by mass percentage), and the mass ratio of photoinitiator 2959 to AAM was 1:1000. The precursor solution was then poured into a sealed acrylic mold, filling the mold cavity to create a vacuum environment. The entire mold was then placed in a UV curing chamber with a wavelength of 365nm and a power of 40W and irradiated with UV light for 3 hours to obtain a strong, fatigue-resistant hydrogel, denoted as 2:1 PAAm-H space-confined linear hydrogel.

[0058] In Examples 1, 2, 3, and 4 above, the calcium chloride content (calcium chloride mass divided by the total mass of calcium chloride and water) was 0%, 10%, 20%, and 40%, respectively, yielding PAAm-L, PAAm-10, PAAm-20, and PAAm-H space-confined linear hydrogels. PAAm-L and PAAm-H correspond to low and high space-confined linear hydrogels, respectively, while PAAm-10 and PAAm-20 are space-confined linear hydrogels intermediate between the two. In Examples 5, 6, and 7, the calcium chloride mass percentage was 40%, classifying them as high space-confined linear hydrogels. However, compared to PAAm-H obtained in Example 4, the difference lies in the monomer concentration, specifically the ratio of AAM monomer to water. In Example 4, the ratio of AAM monomer to water was 1:1, but in Examples 5, 6 and 7, the ratios of AAM monomer to water were 0.25:1, 0.5:1 and 2:1, respectively. Therefore, the high space-confined linear hydrogels obtained in Examples 5, 6 and 7 are designated as 0.25:1PAAm-H, 0.5:1PAAm-H and 2:1PAAm-H.

[0059] To demonstrate the effect of different formulation parameters on the performance of the final hydrogel, mechanical strength characterization tests were conducted on the above-mentioned PAAm-L, PAAm-10, PAAm-20, PAAm-H, 0.25:1 PAAm-H, 0.5:1 PAAm-H, and 2:1 PAAm-H hydrogels. The different characterization results are shown below.

[0060] 1. Uniaxial tensile tests were performed on four space-confined linear hydrogels: PAAm-L, PAAm-10, PAAm-20, and PAAm-H. In this embodiment, the loading rate was 100 mm / min (unless otherwise specified, this tensile rate applies to all tensile tests below). A specimen measuring 50 mm long × 10 mm wide × 2 mm thick was used. The modulus was calculated based on the first 10% of the tensile curve, and the maximum strength was obtained from the maximum stress. The results are as follows: Figure 1 As shown. From Figure 1 As can be seen, with the increase of CaCl2 content, the spatial confinement of the hydrogel is enhanced, and the modulus and tensile strength of the hydrogel are improved.

[0061] 2. The same uniaxial tensile test was performed on three high space-confined linear hydrogels with different monomer concentrations: 0.25:1 PAAm-H, 0.5:1 PAAm-H, and 2:1 PAAm-H. Figure 2 Tensile plots of three high space-confined linear hydrogels with different monomer concentrations are shown. It can be seen that as the monomer concentration decreases, the modulus and tensile strength of PAAm-H hydrogel decrease significantly. Therefore, the optimal ratio of AAM monomer to water is 1:1 to 2:1.

[0062] 3. Fracture toughness tests were conducted on four types of space-confined linear hydrogels: PAAm-L, PAAm-10, PAAm-20, and PAAm-H. In this embodiment, a pure shear specimen (10 mm long × 50 mm wide × 2 mm thick) was used. Tensile tests were performed on both cracked and uncracked specimens to obtain the fracture toughness. Fracture toughness is an important indicator characterizing a material's resistance to crack propagation. Figure 3 The fracture toughness test results of four space-confined linear hydrogels, PAAm-L, PAAm-10, PAAm-20, and PAAm-H, are presented. It can be seen that the fracture toughness of the highly space-confined linear hydrogel PAAm-H reaches 3800 J / m. 2 Compared to PAAm-L low-space-confined linear hydrogel, its fracture toughness is increased by 6 times.

[0063] 4. Dissipation tests were performed on the spatially confined linear hydrogels PAAm-L, PAAm-10, PAAm-20, and PAAm-H. In this embodiment, the dissipation test used a sample with a length of 50 mm × 10 mm × 2 mm and a thickness of 2 mm. Loading and unloading were performed under conditions of elongation of 2, 3, and 4 mm. The dissipation ratio was obtained by comparing the area enclosed by the loading / unloading curve with the area below the loading curve. Figure 4 The results of dissipation tests for four different spatially confined linear hydrogels show that the highly spatially confined linear hydrogel PAAm-H has good elasticity under low-frequency (approximately 0.16 Hz) loads and is not prone to residual deformation.

[0064] 5. Fatigue tests were conducted on the highly space-confined linear hydrogel PAAm-H. Figure 5 The fatigue threshold diagram of PAAm-H is shown, with the ordinate representing the crack propagation rate and the abscissa representing the corresponding energy release rate. The X-intercept represents the fatigue threshold of the hydrogel, i.e., the hydrogel with cracks will not propagate cracks under cyclic loading below this energy release rate. The results indicate that the highly space-confined linear hydrogel PAAm-H possesses excellent fatigue resistance.

[0065] 6. Viscoelastic characterization of low-space-confined linear hydrogel PAAm-L and high-space-confined linear hydrogel PAAm-H was performed. In this embodiment, viscoelastic characterization was conducted using a rheometer at room temperature (20°C) with a shear strain of 0.5% and a frequency sweep from 0.1 to 100 rpm to obtain the tangent of the loss angle—the loss coefficient. Simultaneously, stress relaxation experiments were performed using a strip sample with a length of 50 mm × 10 mm × 2 mm thickness, stretched to twice its original length at 100 mm / min and maintained to obtain the stress relaxation results. Figure 6The results of rheological frequency sweep and stress relaxation experiments for the two hydrogels are shown. It can be seen that compared with the low space confinement linear hydrogel PAAm-L, the high space confinement linear hydrogel PAAm-H has a higher loss coefficient at high frequencies, and it still has a continuing upward trend. This indicates that the high space confinement linear hydrogel PAAm-H can effectively block high-frequency loads.

[0066] 7. Impact resistance tests were conducted on the spatially confined linear hydrogels PAAm-L, PAAm-10, PAAm-20, and PAAm-H. In this embodiment, an iron ball with a diameter of 25 mm was dropped from the same height (20 cm) during the impact test. The energy absorption ratio before and after the impact was calculated based on the height of the rebound of the iron ball after impacting the hydrogel. Figure 7 The results of a falling ball impact test on the space-confined linear hydrogel are presented. It can be seen that as the space confinement increases, the energy absorption ratio of the hydrogel increases from 67% to 98%. Therefore, the PAAm-H high-space-confined linear hydrogel designed in this invention can effectively block impacts and is an excellent damping hydrogel. However, even the PAAm-L low-space-confined linear hydrogel exhibits good damping performance, with an energy absorption ratio reaching 67%, which can fully meet the application requirements in some scenarios where damping performance requirements are lower.

[0067] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all technical solutions obtained through equivalent substitution or transformation fall within the protection scope of the present invention.

Claims

1. A method for preparing a strong and fatigue-resistant hydrogel for shock absorption, characterized in that, include: S1. Using water as a solvent, add acrylamide, calcium chloride and initiator, mix thoroughly to prepare a precursor solution, wherein the mass ratio of acrylamide to water is (1~2):1, the mass ratio of calcium chloride to water is (0.25~2 / 3):1, and the mass ratio of initiator to monomer is (0.0005~0.01):1; S2. Place the precursor liquid in a transparent mold and irradiate it with ultraviolet light in a vacuum environment for 1 to 3 hours to obtain a strong and fatigue-resistant hydrogel. The ultraviolet wavelength used for the ultraviolet irradiation is 360 to 370 nm and the power is 35 to 45 W.

2. The method for preparing a strong and fatigue-resistant hydrogel for shock absorption as described in claim 1, characterized in that, When preparing the precursor solution, the mass ratio of acrylamide to water is 1:1, and the mass ratio of calcium chloride to water is 2 / 3:

1.

3. The method for preparing a strong and fatigue-resistant hydrogel for shock absorption as described in claim 1, characterized in that, The ultraviolet irradiation used a wavelength of 365 nm, a power of 40 W, and an irradiation time of 3 hours.

4. The method for preparing a strong and fatigue-resistant hydrogel for shock absorption as described in claim 1, characterized in that, The initiator is photoinitiator 2959.

5. The method for preparing a strong and fatigue-resistant hydrogel for shock absorption as described in claim 1, characterized in that, When preparing the precursor solution, the mass ratio of the initiator to the monomer is 0.001:

1.

6. A strong and fatigue-resistant hydrogel for shock absorption prepared by the preparation method according to any one of claims 1 to 5.

7. The application of the strong and fatigue-resistant hydrogel for shock absorption as described in claim 6 as a damping material.

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