A high-damping composite material and a preparation method and application thereof

Abstract

The present application relates to the technical field of high polymer damping material, and provides a high damping composite material, a preparation method and application thereof, the high damping composite material comprises a porous framework and a polymer fluid filling the pores of the porous framework; the porous framework serves as a mechanical support to maintain mechanical stability on one hand, and through capillary force, has a mutual physical interaction with the network structure of the polymer fluid to limit the cold flow of the fluid; meanwhile, the whole chain relaxation of the network structure of the polymer fluid ensures that the high damping composite material prepared by the present application has high energy dissipation in a wide frequency and wide temperature range; under the condition of a shear strain of 0.5% for rheological testing by a rheometer, the change multiple of the storage modulus of the high damping composite material is 4-10, the effective damping frequency range is 10 ‑2 ‑10 3 rad / s, the effective damping temperature range is minus 30-200 DEG C, and the damping coefficient is greater than 0.3.

Description

Technical Field

[0001] This invention relates to the field of polymer damping materials technology, and in particular to a high-damping composite material, its preparation method, and its application. Background Technology

[0002] Polymer damping materials, also known as polymer vibration-absorbing materials, are functional materials that utilize the viscoelastic relaxation mechanism unique to polymers to convert mechanical vibrations into heat energy, thereby preventing or mitigating the destructive effects of mechanical vibrations on components. Therefore, polymer damping materials have wide applications in many fields such as aerospace, transportation, and precision instruments.

[0003] With the trend towards higher power, stronger drive, and longer cycle times in electronic devices and engineering equipment, ultra-high or ultra-low frequency vibrations and noise are generated. This necessitates that polymer damping materials possess a wide effective damping range. Although traditional damping materials can achieve high damping capabilities over a wide temperature and frequency range by introducing multiple polymer relaxation mechanisms, this often leads to drastic changes in mechanical properties, inevitably compromising structural stability and operational safety. Therefore, there is an urgent need to develop polymer composite materials that combine stable mechanical properties with high damping performance to adapt to a wider range of applications and improve structural safety and service life.

[0004] CN110951023A discloses a room-temperature repairable polymeric damping material, its preparation method, and its application, comprising the following raw materials: polyol, isocyanate, chain extender / crosslinker, and solvent; the polyol includes amino-terminated or hydroxyl-terminated polyols; the molar ratio of the polyol to isocyanate is (1.1-1.3):1; and the degree of crosslinking of the room-temperature repairable polymeric damping material is 5-30%. However, when this technical solution is applied, the widest temperature range corresponding to a loss factor greater than 0.3 is only 15-77℃. In some technical fields, such as when an automobile engine is running, the local temperature can reach 100℃ or above. The polymeric damping material prepared in this technical solution will lose its performance due to the unsuitable temperature range, resulting in unexpected malfunctions, which will affect the use of the device and may even cause some safety accidents.

[0005] CN117467278A discloses a high-damping silicone rubber and its preparation method. The raw materials include silicone rubber monomers, a crosslinking agent, a polymer containing secondary valence bonds, and a linear polymer fluid. This technical solution provides a silicone rubber with a permanently chemically crosslinked polymer network, ensuring the silicone rubber material's ability to maintain its shape and undergo reversible deformation. Simultaneously, the polymer containing secondary valence bonds and the linear polymer fluid provide two energy dissipation mechanisms for the silicone rubber material, enabling it to exhibit excellent damping performance over a wide frequency band or temperature range. Specifically, the silicone rubber prepared by this technical solution exhibits excellent damping performance over a temperature range of -30 to 120°C or over a 10... -2 -10 2 Within the rad / s frequency range, the damping coefficient is above 0.3. However, in some technical fields, such as rockets, missiles, and satellites in aerospace, or optical instruments, medical equipment, and semiconductor manufacturing equipment in precision instruments, the devices involved require a higher effective damping frequency, above 100 rad / s. Therefore, the silicone rubber in this technical solution cannot meet this requirement, and it is necessary to develop polymer damping materials with a higher effective damping frequency. More importantly, the high-damping silicone rubber prepared by this technical solution has a storage modulus change factor of greater than or equal to 10.

[0006] Based on the above-mentioned existing technology, existing polymer damping materials have technical problems that urgently need to be solved, such as the inability to maintain stable mechanical properties while having a wide temperature range and a wide frequency range. Summary of the Invention

[0007] To solve the above technical problems, the present invention provides a high-damping composite material, the high-damping composite material comprising a porous framework and a polymer fluid filling the pores of the porous framework;

[0008] The mass ratio of the porous framework to the polymer fluid is (5-50):(50-95);

[0009] Rheological tests were conducted using a rheometer under a shear strain of 0.5%. The storage modulus of the high-damping composite material changed by a factor of 4-10, and the effective damping frequency range was 10. -2 -10 3 rad / s, effective damping temperature range is -30 to 200℃, damping coefficient is greater than 0.3.

[0010] Furthermore, the rheometer is an Anton Paar flat plate rheometer.

[0011] Furthermore, the change factor of the energy storage modulus of the high-damping composite material is the ratio of the modulus obtained by the high-frequency test to the modulus obtained by the low-frequency test; wherein the frequency of the high-frequency test is 1000 rad / s, and the frequency of the low-frequency test is 0.01 rad / s.

[0012] Furthermore, the porous frame has a foam structure or a honeycomb structure.

[0013] Furthermore, the pore diameter of the foam structure is 10-1000 μm.

[0014] Furthermore, the pore diameter of the honeycomb structure is 10-1000 μm.

[0015] Furthermore, the porosity of the porous frame is 50-98%.

[0016] Further, the porosity = (1 - relative density) × 100%;

[0017] Where relative density = apparent density of porous framework / true density of porous framework;

[0018] Apparent density of porous framework = mass of porous framework / total volume of porous framework;

[0019] The actual density of the porous framework is the density of the raw material itself.

[0020] Furthermore, the porous frame is made of one or more of the following materials: metal rubber, polyurethane, and ethylene-vinyl acetate copolymer (EVA).

[0021] Furthermore, the metal rubber is made of stainless steel.

[0022] Furthermore, the polymer fluid has a network structure, which is a dynamically cross-linked polymer fluid network or a composite network composed of fluid polymers with different weight-average molecular weights.

[0023] Furthermore, the raw materials for preparing the polymer fluid include one or more of dynamic crosslinking agents and linear polymer fluids.

[0024] Furthermore, the mass ratio of the dynamic crosslinking agent to the linear polymer fluid is (0-50):(50-90).

[0025] Furthermore, the dynamic crosslinking agent is polyborosiloxane.

[0026] Furthermore, the weight-average molecular weight of the polyborosiloxane is 800-5000.

[0027] Furthermore, the linear polymer fluid is a linear polysiloxane.

[0028] Furthermore, the linear polysiloxane is in a liquid state at room temperature.

[0029] Furthermore, the linear polysiloxane includes one or more of polydimethylsiloxane, polyphenylmethylsiloxane, and polydiethylsiloxane;

[0030] Linear polysiloxanes can also be composed of the same type of linear polysiloxane with different weight-average molecular weights.

[0031] Furthermore, the linear polysiloxane is preferably polydimethylsiloxane.

[0032] Furthermore, the linear polymer fluid has a weight-average molecular weight of 50,000-300,000.

[0033] Furthermore, the weight-average molecular weight of the linear polymer fluid is preferably 60,000-260,000.

[0034] Furthermore, the molecular weight of the polydimethylsiloxane is one or more of 63,000, 139,000, 140,000, and 260,000.

[0035] Furthermore, the molecular weight of the polyphenylmethylsiloxane is one or more of 40,000, 160,000, and 250,000.

[0036] Furthermore, the molecular weight of the polydiethylsiloxane is one or more of 10,000, 90,000, and 240,000.

[0037] This invention also provides a method for preparing a high-damping composite material, comprising the following steps:

[0038] Step 1: Prepare the precursor solution of the polymer fluid;

[0039] Step 2: The precursor solution is introduced into the porous framework by impregnation and fills the pores of the porous framework, and then dried to obtain the high-damping composite material.

[0040] Furthermore, the preparation process of the precursor solution in step 1 is as follows: one or more of the dynamic crosslinking agent and linear polymer fluid are dispersed in an organic solvent according to a mass ratio, and stirred evenly to obtain the precursor solution.

[0041] Furthermore, the mass ratio of organic solvent to solute in the precursor solution is (0.5-5):1.

[0042] Furthermore, the organic solvent is one or more of toluene, n-hexane, xylene, and tetrahydrofuran.

[0043] Furthermore, the stirring temperature is room temperature.

[0044] Furthermore, in step 2, the drying temperature is 50-100℃ and the time is 24-48h, in order to dry out the volatile organic solvents.

[0045] Furthermore, in step 2, the drying temperature is 60-70℃ and the time is 36-48h.

[0046] Furthermore, the number of times of impregnation and drying in step 2 is greater than or equal to 1, until the pores of the porous framework are filled with the polymer fluid.

[0047] Furthermore, the dynamic crosslinking agent mentioned in step 1 is a polyborosiloxane, which is obtained by direct purchase or preparation;

[0048] The preparation method of polyborosiloxane includes the following steps: mixing boric acid, alcohol solvent and hydroxyl-terminated polydimethylsiloxane to carry out a dehydration condensation reaction to obtain polyborosiloxane.

[0049] Furthermore, the mass ratio of boric acid to alcohol solvent is 1:(30-60).

[0050] Furthermore, the mass ratio of boric acid to alcohol solvent is preferably 1:50.

[0051] Furthermore, the mass ratio of the boric acid to the hydroxyl-terminated polydimethylsiloxane is 1:(30-70).

[0052] Furthermore, the mass ratio of boric acid to hydroxyl-terminated polydimethylsiloxane is preferably 1:40.

[0053] Furthermore, the alcohol solvent is methanol.

[0054] Furthermore, the weight-average molecular weight of the hydroxyl-terminated polydimethylsiloxane is 500-5000.

[0055] Furthermore, the weight-average molecular weight of the hydroxyl-terminated polydimethylsiloxane is preferably 4200.

[0056] Furthermore, the dehydration condensation reaction is carried out at room temperature for 0.5-3 hours.

[0057] Furthermore, the reaction time is preferably 1.5 hours.

[0058] Furthermore, the reaction is carried out under stirring conditions at a speed of 1000-1500 rpm.

[0059] Further, the preparation method of the polyborosiloxane is as follows: according to the mass ratio, boric acid is first dissolved in the alcohol solvent to obtain an alcohol solution of boric acid, and then the hydroxyl-terminated polydimethylsiloxane is added to the alcohol solution of boric acid. The reaction is carried out under stirring. After the dehydration condensation reaction is completed, the mixture is centrifuged to obtain the polyborosiloxane.

[0060] Furthermore, the centrifugation speed is 5000 rpm and the centrifugation time is 5 min.

[0061] The present invention also provides a polymer damping material product, which is prepared from the above-mentioned high damping composite material.

[0062] Furthermore, the polymer damping material products include, but are not limited to, sealing rubber, precision instrument shock-absorbing pads, sports shoe soles, and personal protective equipment.

[0063] Furthermore, the personal protective equipment includes, but is not limited to, knee pads and bulletproof vests.

[0064] The beneficial effects of this invention are as follows:

[0065] 1. This invention provides a high-damping composite material, comprising a porous framework and a polymer fluid filling the pores of the porous framework. The porous framework serves two purposes: firstly, it provides mechanical support, maintaining mechanical stability; secondly, through capillary action, it interacts with the network structure of the polymer fluid, restricting the cold flow of the fluid. Simultaneously, the overall relaxation of the polymer fluid network structure ensures that the high-damping composite material prepared by this invention exhibits high energy dissipation (damping) over a wide frequency and temperature range. Rheological testing using a rheometer under a shear strain of 0.5% shows that the storage modulus of the high-damping composite material changes by a factor of 4-10, and the effective damping frequency range is 10. -2 -10 3 rad / s, effective damping temperature range is -30 to 200℃, damping coefficient is greater than 0.3;

[0066] 2. The polymer fluid has a network structure, which is either a dynamically cross-linked polymer fluid network or a composite network composed of fluid polymers with different weight-average molecular weights (without a dynamic cross-linking agent). Both types of polymer fluid network structures can achieve a molecular weight of 10... -2 -10 3 Multiple relaxations are performed over a wide frequency range of rad / s and a wide temperature range of -30 to 200°C, thereby achieving high damping performance of the composite material. Furthermore, the composite material prepared by this invention has a damping coefficient greater than 0.3 within the above temperature and frequency range, while the change in its storage modulus does not exceed 10 times.

[0067] 3. When the network structure of the polymer fluid is a dynamically cross-linked polymer fluid network, the essence of using a dynamic cross-linking agent is that the boron atoms in the polyborosiloxane have empty orbitals, which can act as acceptors of unshared electron pairs on oxygen atoms, thereby forming non-bonded complexes, causing physical cross-linking between molecules, and further strengthening the interaction between the porous framework and the polymer fluid. When the network structure of the polymer fluid is a composite network composed of fluid polymers with different weight-average molecular weights, different degrees of molecular chain entanglement networks are formed due to the different entanglement properties of molecular chains of different lengths. Therefore, the polymer fluid can achieve mutual cooperation with the porous framework in the microstructure, thereby achieving good damping effect over a wide temperature and frequency range.

[0068] 4. The high-damping composite material provided by this invention overcomes the problems of low damping coefficient, narrow effective frequency / temperature range, and poor mechanical stability of traditional polymer damping materials. It is a high-damping, wide-temperature-range, wide-bandwidth, and highly stable composite material, which is expected to be widely used in precision instrument protection, body health protection, noise control, equipment vibration reduction and other fields. Furthermore, this invention also provides a method for preparing the composite material. The preparation method is simple, low-cost, and easy to achieve large-scale preparation. Attached Figure Description

[0069] Figure 1 This is a schematic diagram of the composition and structure of the high-damping composite material in Embodiment 2 of the present invention;

[0070] Figure 2 Microscopic image of the high-damping composite material of Example 2 of the present invention;

[0071] Figure 3 This is a graph showing the modulus-angular frequency dependence of the high-damping composite material in Example 2 of the present invention.

[0072] Figure 4 This is a graph showing the dependence of the loss factor (damping coefficient) on the angular frequency of the high-damping composite material in Embodiment 2 of the present invention.

[0073] The names of the labels in the diagram are:

[0074] 1. Porous framework; 2. Polymer fluid. Detailed Implementation

[0075] Example 1

[0076] This embodiment first provides a method for preparing polyborosiloxane, including the following steps: Boric acid is dissolved in methanol at a mass ratio of 1:50 to obtain a boric acid methanol solution. Then, the hydroxyl-terminated polydimethylsiloxane is added to the boric acid methanol solution at a mass ratio of 1:40 to the boric acid, wherein the hydroxyl-terminated polydimethylsiloxane has a weight-average molecular weight of 4200. The reaction is carried out at room temperature for 1.5 hours under a stirring speed of 1000 rpm. After the dehydration condensation reaction is completed, the mixture is centrifuged at a speed of 5000 rpm for 5 minutes to obtain the polyborosiloxane.

[0077] The dynamic crosslinking agent involved in the following examples is the polyborosiloxane prepared in this example.

[0078] Example 2

[0079] This embodiment provides a high-damping composite material, such as... Figure 1-2 As shown, the high-damping composite material includes a porous frame 1 and a polymer fluid 2 filling the pores of the porous frame;

[0080] In this embodiment, the porous framework 1 is a foam structure with a pore diameter ranging from 300 to 600 μm and a porosity of 78%, and the material is polyurethane; the polymer fluid 2 has a network structure, which is a dynamically cross-linked polymer fluid network. The raw materials for preparing the polymer fluid include the dynamically cross-linking agent polyborosiloxane prepared in Example 1, and polydimethylsiloxane with a weight-average molecular weight of 140,000 as a linear polymer fluid.

[0081] Therefore, in this embodiment, the mass ratio of the porous framework of the polyurethane foam structure, polyborosiloxane, and polydimethylsiloxane with a weight average molecular weight of 140,000 is 10:45:45.

[0082] This embodiment also provides a method for preparing the above-mentioned high-damping composite material, including the following steps:

[0083] Step 1: Preparation of the precursor solution for polymer fluid 2: 45 parts of the dynamic crosslinking agent polyborosiloxane prepared in Example 1 and 45 parts of polydimethylsiloxane with a weight average molecular weight of 140,000 are dispersed in the organic solvent toluene as a linear polymer fluid and stirred at room temperature to obtain the precursor solution; the mass ratio of organic solvent to solute in the precursor solution is 1:1.

[0084] Step 2: The precursor solution is introduced into the porous frame 1 by impregnation and fills the pores of the porous frame. The porous frame 1 interacts with the network structure of the precursor solution by capillary force, which restricts its cold flow. Then, it is dried to obtain the high-damping composite material.

[0085] The drying temperature is 60°C and the time is 48 hours. In this embodiment, the precursor solution is introduced into the porous frame 1 multiple times in an impregnation-drying cycle until the pores of the porous frame are filled after the second cycle.

[0086] Rheological tests were conducted using an Anton Paar flat plate rheometer under a shear strain of 0.5%. The storage modulus of the high-damping composite material changed by a factor of 6.7, and the effective damping frequency range was 10. -2 -10 3 The effective damping temperature range is 0-200℃, and the damping coefficient is greater than 0.3. That is, no damping coefficient less than or equal to 0.3 was found in the entire temperature scan range.

[0087] The modulus-angular frequency relationship curve obtained using an Anton Paar flat plate rheometer is shown below. Figure 3 As shown in the figure. Where G' is the storage modulus, G'' is the loss modulus, and G'' / G' is the loss factor. The calculation results are as follows: Figure 4 As shown, Figure 3-4 The results show that, within a wide frequency range of the test, the storage modulus and loss modulus of the high-damping composite material exhibit limited changes, while the loss factor (damping coefficient) remains above 0.3, indicating that the high-damping composite material possesses both mechanical stability and high damping performance.

[0088] Example 3

[0089] This embodiment provides a high-damping composite material, which includes a porous framework and a polymer fluid filling the pores of the porous framework;

[0090] In this embodiment, the porous framework is a honeycomb structure with a pore diameter ranging from 500 to 1000 μm and a porosity of 90%, and is made of polyurethane; the polymer fluid has a network structure, which is a composite network composed of fluid polymers with different weight-average molecular weights, and the raw materials for preparing the polymer fluid include polydimethylsiloxane with weight-average molecular weights of 63,000, 139,000, and 260,000, respectively, as a linear polymer fluid;

[0091] Therefore, in this embodiment, the mass ratio of the porous framework of the polyurethane honeycomb structure to the polydimethylsiloxane with a weight-average molecular weight of 63,000, 139,000, and 260,000 is 10:30:30:30.

[0092] This embodiment also provides a method for preparing the above-mentioned high-damping composite material, including the following steps:

[0093] Step 1: Preparation of the precursor solution for the polymer fluid: 30 parts each of polydimethylsiloxane with weight average molecular weights of 63,000, 139,000, and 260,000, respectively, were dispersed in toluene as a linear polymer fluid and stirred at room temperature to obtain the precursor solution; the mass ratio of organic solvent to solute in the precursor solution was 2.5:1.

[0094] Step 2: The precursor solution is introduced into the porous framework by impregnation and fills the pores of the porous framework. The porous framework interacts with the network structure of the precursor solution through capillary force, which restricts its cold flow. Then, it is dried to obtain the high-damping composite material.

[0095] The drying temperature is 60°C and the time is 48 hours. In this embodiment, the precursor solution is introduced into the porous frame multiple times in an impregnation-drying cycle until the pores of the porous frame are filled after the fourth cycle.

[0096] Rheological tests were conducted using an Anton Paar flat plate rheometer under a shear strain of 0.5%. The storage modulus of the high-damping composite material changed by a factor of 5.9, and the effective damping frequency range was 10. -2 -10 2 The effective damping temperature range is 0-175℃, and the damping coefficient is greater than 0.3. That is, no damping coefficient less than or equal to 0.3 was found in the entire temperature scan range.

[0097] Example 4

[0098] This embodiment provides a high-damping composite material, which includes a porous framework and a polymer fluid filling the pores of the porous framework;

[0099] In this embodiment, the porous framework is a foam structure with a pore diameter ranging from 500 to 900 μm and a porosity of 90%, and the material is metal rubber, specifically stainless steel rubber; the polymer fluid has a network structure, which is a dynamically cross-linked polymer fluid network, and the raw materials for preparing the polymer fluid include the dynamically cross-linking agent polyborosiloxane prepared in Example 1, and polydimethylsiloxane with a weight-average molecular weight of 140,000 as a linear polymer fluid;

[0100] Therefore, in this embodiment, the mass ratio of the porous framework of the metal rubber foam structure, polyboron siloxane, and polydimethylsiloxane with a weight average molecular weight of 140,000 is 50:25:25.

[0101] This embodiment also provides a method for preparing the above-mentioned high-damping composite material, including the following steps:

[0102] Step 1: Preparation of the precursor solution for the polymer fluid: 25 parts of the dynamic crosslinking agent polyborosiloxane prepared in Example 1 and 25 parts of polydimethylsiloxane with a weight average molecular weight of 140,000 are dispersed in the organic solvent toluene as a linear polymer fluid and stirred at room temperature to obtain the precursor solution; the mass ratio of organic solvent to solute in the precursor solution is 1:1.

[0103] Step 2: The precursor solution is introduced into the porous framework by impregnation and fills the pores of the porous framework. The porous framework interacts with the network structure of the precursor solution through capillary force, which restricts its cold flow. Then, it is dried to obtain the high-damping composite material.

[0104] The drying temperature is 60°C and the time is 48 hours. In this embodiment, the precursor solution is introduced into the porous frame multiple times in an impregnation-drying cycle until the pores of the porous frame are filled after the third cycle.

[0105] Rheological tests were conducted using an Anton Paar flat plate rheometer under a shear strain of 0.5%. The storage modulus of the high-damping composite material changed by a factor of 8.0, and the effective damping frequency range was 10. -1 -10 1 The effective damping temperature range is -20 to 50°C, and the damping coefficient is greater than 0.3. That is, no damping coefficient less than or equal to 0.3 was found in the entire temperature scan range.

[0106] Example 5

[0107] This embodiment provides a high-damping composite material, which includes a porous framework and a polymer fluid filling the pores of the porous framework;

[0108] In this embodiment, the porous framework is a foam structure with a pore diameter ranging from 700 to 900 μm and a porosity of 90%, and the material is ethylene-vinyl acetate copolymer (EVA); the polymer fluid has a network structure, which is a composite network composed of fluid polymers with different weight-average molecular weights, and the raw materials for preparing the polymer fluid include polyphenylmethylsiloxane with weight-average molecular weights of 40,000, 160,000, and 250,000, respectively, as a linear polymer fluid;

[0109] Therefore, in this embodiment, the mass ratio of the porous framework of the ethylene-vinyl acetate copolymer foam structure to the polyphenylmethylsiloxane with a weight average molecular weight of 40,000, 160,000, and 250,000 is 10:30:30:30.

[0110] This embodiment also provides a method for preparing the above-mentioned high-damping composite material, including the following steps:

[0111] Step 1: Preparation of the precursor solution for the polymer fluid: 30 parts each of polyphenylmethylsiloxane with weight average molecular weights of 40,000, 160,000, and 250,000, respectively, were dispersed in toluene as a linear polymer fluid and stirred at room temperature to obtain the precursor solution; the mass ratio of organic solvent to solute in the precursor solution was 2.5:1.

[0112] Step 2: The precursor solution is introduced into the porous framework by impregnation and fills the pores of the porous framework. The porous framework interacts with the network structure of the precursor solution through capillary force, which restricts its cold flow. Then, it is dried to obtain the high-damping composite material.

[0113] The drying temperature is 60°C and the time is 48 hours. In this embodiment, the precursor solution is introduced into the porous frame multiple times in an impregnation-drying cycle until the pores of the porous frame are filled after the third cycle.

[0114] Rheological tests were conducted using an Anton Paar flat plate rheometer under a shear strain of 0.5%. The storage modulus of the high-damping composite material changed by a factor of 8.9, and the effective damping frequency range was 10. -2 -10 3 The effective damping temperature range is -30 to 180°C, and the damping coefficient is greater than 0.3. That is, no damping coefficient less than or equal to 0.3 was found in the entire temperature scan range.

[0115] Example 6

[0116] This embodiment provides a high-damping composite material, which includes a porous framework and a polymer fluid filling the pores of the porous framework;

[0117] In this embodiment, the porous framework is a foam structure with a pore diameter ranging from 700 to 900 μm and a porosity of 90%, and the material is ethylene-vinyl acetate copolymer (EVA); the polymer fluid has a network structure, which is a composite network composed of fluid polymers with different weight-average molecular weights, and the raw materials for preparing the polymer fluid include polydiethylsiloxane with weight-average molecular weights of 10,000, 90,000, and 240,000 as linear polymer fluids;

[0118] Therefore, in this embodiment, the mass ratio of the porous framework of the ethylene-vinyl acetate copolymer foam structure to polydiethylsiloxane with a weight average molecular weight of 10,000, 90,000, and 240,000 is 10:30:30:30.

[0119] This embodiment also provides a method for preparing the above-mentioned high-damping composite material, including the following steps:

[0120] Step 1: Preparation of the precursor solution for the polymer fluid: 30 parts each of polydiethylsiloxane with weight average molecular weights of 10,000, 90,000, and 240,000, respectively, were dispersed in toluene as a linear polymer fluid and stirred at room temperature to obtain the precursor solution; the mass ratio of organic solvent to solute in the precursor solution was 2.5:1.

[0121] Step 2: The precursor solution is introduced into the porous framework by impregnation and fills the pores of the porous framework. The porous framework interacts with the network structure of the precursor solution through capillary force, which restricts its cold flow. Then, it is dried to obtain the high-damping composite material.

[0122] The drying temperature is 60°C and the time is 48 hours. In this embodiment, the precursor solution is introduced into the porous frame multiple times in an impregnation-drying cycle until the pores of the porous frame are filled after the third cycle.

[0123] Rheological tests were conducted using an Anton Paar flat plate rheometer under a shear strain of 0.5%. The storage modulus of the high-damping composite material changed by a factor of 9.8, and the effective damping frequency range was 10. -2 -10 3 The effective damping temperature range is -30 to 160°C, and the damping coefficient is greater than 0.3. That is, no damping coefficient less than or equal to 0.3 was found in the entire temperature scan range.

[0124] Comparative Example 1

[0125] Compared to Example 2, this comparative example omits the porous framework and provides a composite material, the specific preparation method of which is as follows:

[0126] Step 1: Preparation of precursor solution: 50 parts of the dynamic crosslinking agent polyborosiloxane prepared in Example 1 and 50 parts of polydimethylsiloxane with a weight average molecular weight of 140,000 are dispersed in the organic solvent toluene and stirred at room temperature to obtain the precursor solution.

[0127] Step 2: Pour the precursor solution into a mold and then dry it to obtain the high-damping composite material; wherein the drying temperature is 60℃ and the time is 48h.

[0128] Rheological tests were conducted using an Anton Paar flat plate rheometer under a shear strain of 0.5%. The storage modulus of the composite material changed by a factor of 530, and the effective damping frequency range was 10. -2 -10 3 rad / s, effective damping temperature range is 0-200℃, damping coefficient is greater than 0.3.

[0129] Comparative Example 2

[0130] Compared to Example 2, this comparative example omits the polymer fluid with a dynamically cross-linked polymer fluid network and uses polyurethane foam as a porous framework, drying it at a drying temperature of 60°C for 48 hours.

[0131] Rheological tests were conducted using an Anton Paar flat plate rheometer under a shear strain of 0.5%. The porous frame exhibited a storage modulus change factor of 2.5, an effective damping frequency range of 0 rad / s, and an effective damping temperature range of 0 °C.

[0132] Comparative Example 3

[0133] Preparation of the high-damping silicone rubber in Example 1 of CN117467278A.

[0134] Rheological tests were conducted using an Anton Paar flat plate rheometer under a shear strain of 0.5%. The storage modulus of the high-damping silicone rubber changed by a factor of 12, and the effective damping frequency range was 10. -2 -10 2 rad / s, with an effective damping temperature range of -30 to 121°C.

[0135] The test results of the examples and comparative examples are compared in Table 1:

[0136] Table 1. Comparison of the properties of composite materials prepared in the examples and comparative examples.

[0137]

[0138] As can be seen from the data in Table 1, the composite materials prepared in Examples 2-6 exhibit small changes in storage modulus over a wide frequency and temperature range, demonstrating significantly high mechanical stability; simultaneously, their damping coefficients reach above 0.3, showing excellent damping performance. Comparative Example 1, which omitted the addition of a porous framework, showed a modulus change factor nearly 100 times that of Examples 2-6 within the test range; Comparative Example 2, which omitted the addition of a dynamically cross-linked fluid matrix, showed extremely poor damping performance with a single framework, and its loss factor did not reach above 0.3; Comparative Example 3, a composite material prepared using existing technology, also showed a higher modulus change factor than Examples 2-6 within the test range.

[0139] It should be understood that the present invention is not limited to what has been described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A high-damping composite material, characterized in that, The high-damping composite material includes a porous framework and a polymer fluid filling the pores of the porous framework; The mass ratio of the porous framework to the polymer fluid is (5-50):(50-95); Rheological tests were conducted using a rheometer under a shear strain of 0.5%. The storage modulus of the high-damping composite material changed by a factor of 4-10, and the effective damping frequency range was 10. -2 -10 3 rad / s, effective damping temperature range is -30 to 200℃, damping coefficient is greater than 0.3; The porous framework is made of one or more of polyurethane and ethylene-vinyl acetate copolymer. The polymer fluid has a network structure, which is a dynamically cross-linked polymer fluid network or a composite network composed of fluid polymers with different weight-average molecular weights. The raw materials for preparing the polymer fluid include linear polymer fluid, or dynamic crosslinking agent and linear polymer fluid; The dynamic crosslinking agent is polyborosiloxane; The linear polymer fluid is a linear polysiloxane; The change factor of the energy storage modulus of the high-damping composite material is the ratio of the modulus obtained by high-frequency testing to the modulus obtained by low-frequency testing; The high-frequency test has a frequency of 1000 rad / s, and the low-frequency test has a frequency of 0.01 rad / s.

2. The high-damping composite material according to claim 1, characterized in that, The porous frame has a foam structure or a honeycomb structure.

3. A method for preparing the high-damping composite material according to any one of claims 1-2, characterized in that, Includes the following steps: Step 1: Prepare the precursor solution of the polymer fluid; Step 2: The precursor solution is introduced into the porous framework by impregnation and fills the pores of the porous framework, and then dried to obtain the high-damping composite material.

4. The method for preparing the high-damping composite material according to claim 3, characterized in that, The preparation process of the precursor solution in step 1 is as follows: one or more of the dynamic crosslinking agent and linear polymer fluid are dispersed in an organic solvent according to the mass ratio, and stirred evenly to obtain the precursor solution.

5. The method for preparing the high-damping composite material according to claim 3, characterized in that, In step 2, the drying temperature is 50-100℃ and the time is 24-48h.

6. A polymer damping material product, characterized in that, It is prepared from the high-damping composite material according to any one of claims 1-2.

7. The polymer damping material product according to claim 6, characterized in that, The polymer damping material products include sealing rubber, precision instrument shock-absorbing pads, sports shoe soles, and personal protective equipment.

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