Addition type damping silicone rubber with dual-mode network and preparation method and application thereof

Abstract

This invention discloses an addition-cure damping silicone rubber with a dual-mode network, its preparation method, and its application, belonging to the field of room-temperature vulcanizing silicone rubber technology. It includes component A and component B; component A, by weight, comprises 100 parts of tetravinyl-terminated polysiloxane, 10-50 parts of silica, and 0.01-0.5 parts of catalyst; component B, by weight, comprises 50-90 parts of low-hydrogen-content terminal hydrogen silicone oil, 10-50 parts of high-hydrogen-content terminal hydrogen silicone oil, 10-50 parts of silica, and 0.01-0.5 parts of inhibitor. This invention improves damping performance by introducing relatively large steric hindrance groups such as ethyl, phenyl, or trifluoropropyl groups onto the main chain of the tetravinyl-terminated polysiloxane, and forms an addition-cure damping silicone rubber with low modulus, excellent toughness, and good damping performance through crosslinking reactions between the tetravinyl-terminated polysiloxane and various terminal hydrogen silicone oils with different hydrogen contents.

Description

Technical Field

[0001] This invention relates to an addition-type damping silicone rubber with a dual-mode network, its preparation method, and its application, belonging to the field of room temperature vulcanizing silicone rubber technology. Background Technology

[0002] With the rapid development of the aerospace field, various precision electronic devices require efficient vibration damping during flight or operation to ensure their functionality. During on-orbit operation, the high-speed rotation of attitude control components such as momentum wheels, flywheels, and control moment gyroscopes can cause micro-vibrations in remote sensing satellites, either locally or as a whole. These vibrations have small amplitudes and wide frequency bands, severely affecting the imaging quality of optical payloads carried on high-resolution satellites. Therefore, developing a damping vibration absorber that can withstand the high-load impact during launch and also achieve attenuation of micro-vibrations under small loads on-orbit has become a key technical challenge for improving the spatial resolution of remote sensing satellites.

[0003] Silicone rubber is a type of viscoelastic damping material with excellent comprehensive properties. Its high silicon-oxygen bond (Si-O) energy allows it to maintain stable viscoelastic properties over a wide temperature range of -60 to 200℃ and even wider, with minimal changes in elastic modulus and hardness. Simultaneously, silicone rubber exhibits excellent resistance to ultraviolet radiation, ozone, and salt spray, making it suitable for aerospace products with extremely high requirements for environmental adaptability and durability. Under micro-vibration conditions, traditional high-modulus damping materials suffer from limited response to small displacements, resulting in low energy dissipation efficiency and failing to achieve ideal damping effects. In contrast, low-modulus silicone rubber can produce an instantaneous response to weak vibrations and efficiently dissipate energy through viscoelastic deformation, providing a solid technical guarantee for the stable operation of high-precision remote sensing satellites and other applications.

[0004] Currently, phenyl damping silicone rubber materials (such as patent CN119978816B) possess high mechanical and damping properties, but their hardness is all above 28 (Shore A), making it difficult to meet the needs of vibration reduction in the field of remote sensing satellites. Therefore, developing a silicone rubber material that combines low modulus, excellent toughness, and good damping properties, and achieving a simple and cost-effective preparation method, remains a pressing technical challenge in this field. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides an addition-cure damping silicone rubber with a dual-mode network. Damping performance is improved by introducing large steric hindrance groups such as ethyl, phenyl, or trifluoropropyl groups onto the tetravinyl-terminated polysiloxane backbone. Furthermore, the tetravinyl-terminated polysiloxane undergoes a crosslinking reaction with various hydrogen-terminated silicone oils of different hydrogen contents, resulting in an addition-cure damping silicone rubber that combines low modulus, excellent toughness, and good damping performance.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: According to a first aspect of the present invention, an addition-cure damping silicone rubber having a dual-mode network is provided, comprising component A and component B; Component A, by weight, comprises 100 parts of tetravinyl-terminated polysiloxane, 10-50 parts of silica, and 0.01-0.5 parts of catalyst; Component B, by weight, comprises 50-90 parts of low-hydrogen-content terminal hydrogen silicone oil, 10-50 parts of high-hydrogen-content terminal hydrogen silicone oil, 10-50 parts of silica, and 0.01-0.5 parts of inhibitor. The low-hydrogen-content terminal hydrogen silicone oil has a hydrogen content of at least 0.1 wt%, and the high-hydrogen-content terminal hydrogen silicone oil has a hydrogen content of less than 0.1 wt%. The catalyst is a platinum catalyst, and the inhibitor is an alkynyl alcohol inhibitor or a vinyl-containing inhibitor; The structure of the tetravinyl-terminated polysiloxane is shown in formula (I):

[0007] Formula (I) R1 to R5 are independently selected from at least one of methyl, phenyl, ethyl, and trifluoropropyl, and 100 ≤ x + y + z ≤ 2000.

[0008] Preferably, 400≤x+y+z≤1100, the value range of x is 0-1100, the value range of y is 0-590, the value range of z is 0-785, and x, y, and z do not all take the value of 0 at the same time.

[0009] The tetravinyl-terminated polysiloxane used in this invention has four active vinyl groups located at both ends of a linear molecular chain. This "end-functionalized" topology avoids the uncontrollability of the network structure caused by random cross-linking of the main chain side groups. By strictly controlling the hydrosilylation reaction to occur at the end of the molecular chain, a cross-linked network with an ideal topology is constructed, enabling the silicone rubber to possess both low modulus and good toughness.

[0010] Introducing sterically hindered side groups such as ethyl, phenyl, or trifluoropropyl groups into the main chain of tetravinyl-terminated polysiloxanes can significantly improve the damping properties of silicone rubber. The introduction of these large-volume substituents significantly increases the steric hindrance of the molecular chain, effectively suppressing the free rotation of the polysiloxane main chain and thus reducing the flexibility of the molecular chain. During deformation under stress, the interaction between the large-volume side groups enhances the internal frictional resistance of the molecular chain segment movement, increasing the dissipation of mechanical energy within the silicone rubber and converting this energy into heat energy. This macroscopically manifests as an increase in the loss factor of the silicone rubber and a broadening of the effective damping temperature range.

[0011] This invention reveals that in the formulation design of room temperature vulcanizing silicone rubber, a single-component hydrogen-terminated silicone oil cannot simultaneously achieve both processability and mechanical properties. This is because while low-hydrogen-content components can impart good toughness to the elastomer, their high viscosity leads to poor system flowability, increasing processing difficulty; while high-hydrogen-content components, although beneficial for rapid curing and improved flowability, tend to result in insufficient mechanical strength of the cured product. To address these contradictions, this invention employs a compound system of various hydrogen-terminated silicone oils with different hydrogen contents, co-cured with tetravinyl-terminated polysiloxanes to prepare silicone rubber. This approach ensures both good processability of the rubber compound and improved mechanical properties.

[0012] Optionally, the vinyl content of the tetravinyl-terminated polysiloxane is 0.05-0.5 wt%, preferably 0.1-0.4 wt%, and more preferably 0.13-0.36 wt%.

[0013] Optionally, R1 and R4 are independently selected from methyl and phenyl, and at least one of them is phenyl; R2 and R3 are independently selected from at least one of methyl, ethyl, and trifluoropropyl, and R2 and R3 are not both methyl; R5 is selected from methyl.

[0014] Optionally, the method for preparing the tetravinyl-terminated polysiloxane is as follows: (1) Mix a specific weight of the first monomer, the second monomer, the third monomer, and the alkaline catalyst according to the values ​​of x, y, and z, and heat to 50-60℃ for vacuum distillation to obtain solution A. The first monomer is selected from at least one of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane. The second monomer is selected from at least one of methylphenylsiloxane mixed ring, hexaphenylcyclotrisiloxane, or octaphenylcyclotetrasiloxane. The methylphenylsiloxane mixed ring is a mixture of trimethyltriphenylcyclotrisiloxane, tetramethyltetraphenylcyclotetrasiloxane, and pentamethylpentaphenylcyclopentasiloxane. The third monomer is selected from hexaethylcyclotrisiloxane or methyltrifluoropropylcyclotrisiloxane. (2) Add the capping agent 1,3-dimethyl-1,1,3,3-tetraethylenedisiloxane to solution A under an inert gas atmosphere, heat to 80-120℃ and react for 3-6 hours to obtain solution B; (3) After the solution B is cooled to room temperature in an inert gas atmosphere, glacial acetic acid is added and the reaction is stirred for 1-2 hours to obtain solution C; (4) Distill solution C under reduced pressure and remove it at room temperature in an inert gas atmosphere to obtain tetravinyl-terminated polysiloxane.

[0015] In step (1) of this invention, the selection of the first monomer, the second monomer, and the third monomer can ensure the generation of different copolymer types. The first monomer is used to provide dimethyl linkages, the second monomer is used to provide methylphenyl linkages or diphenyl linkages, and the third monomer is used to provide methyltrifluoropropyl linkages or diethyl linkages. By adjusting the feed ratio of the relevant raw materials, the copolymer structure and ratio of tetravinyl-terminated polysiloxane can be changed.

[0016] Optionally, the vacuum distillation time in step (1) is 0.5-2h, and the vacuum distillation temperature in step (4) is 160-180℃, and the time is 3-6h.

[0017] Optionally, the alkaline catalyst is selected from at least one of sodium hydroxide silanolate, potassium hydroxide silanolate, cesium hydroxide silanolate, and lithium hydroxide silanolate, preferably cesium hydroxide silanolate.

[0018] Optionally, the amount of the alkaline catalyst added in step (1) is 1-10% of the mass of the cyclosiloxane monomer.

[0019] Optionally, the amount of capping agent added in step (2) is 0.1-1.0% of the mass of solution A; preferably 0.25-0.70%.

[0020] At this capping agent dosage, tetravinyl-terminated polysiloxanes with a vinyl content of 0.1-0.4 wt% can be obtained. If the amount of capping agent is too small, the resulting tetravinyl-terminated polysiloxane will have an excessively high molecular weight and viscosity, making it extremely difficult to expel microbubbles during processing. This will eventually form stress concentration points inside the silicone rubber, resulting in a significant decrease in mechanical properties. If the amount of capping agent is too large, the resulting tetravinyl-terminated polysiloxane will have a low molecular weight and viscosity, leading to excessively dense crosslinking points in the system. This will make the silicone rubber prone to brittle fracture and result in poor mechanical properties.

[0021] Optionally, the hydrogen content of the high hydrogen content end-hydrogen silicone oil is 0.1-0.5 wt%, preferably 0.1-0.4 wt%.

[0022] Optionally, the hydrogen content of the low-hydrogen-content end-hydrogen silicone oil is 0.005-0.09 wt%.

[0023] Optionally, the weight ratio of the high-hydrogen-content end-hydrogen silicone oil to the low-hydrogen-content end-hydrogen silicone oil is 1:(1-9), preferably 1:(1.5-9).

[0024] Within this ratio range, when the high-hydrogen-content end-hydrogen silicone oil (i.e., short chains) is stretched to its limit and begins to break, the surrounding low-hydrogen-content end-hydrogen silicone oil (i.e., long chains) is subsequently stretched to its ultimate orientation state. This orientation effect enhances the interaction between molecular chains, allowing the silicone rubber to withstand greater stress before fracture. If the short-chain content is too high, due to its small molecular size and fast diffusion rate, it preferentially participates in the cross-linking reaction, producing a significant steric hindrance effect, reducing the reactivity of the remaining vinyl groups, and consequently, a large number of long chains form dangling chains or free chains, resulting in a sticky silicone rubber surface or the precipitation of oily substances during use. Conversely, if the long-chain content is too high, not only will the system viscosity increase significantly and the processing performance deteriorate, but the overall cross-linking density of the silicone rubber will also be insufficient, making cracks easily propagate and reducing mechanical properties.

[0025] Optionally, the catalyst is at least one of isopropanol chloroplatinate solution, tetramethyldivinyldisiloxane chloroplatinate complex, and tetramethyltetravinylcyclotetrasiloxane chloroplatinate complex, wherein the platinum content is 1000-5000 ppm by mass.

[0026] Optionally, the inhibitor is at least one selected from 1-ethynyl-1-cyclohexanol, 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, 4-vinylpyridine, and tetravinyltetramethylcyclotetrasiloxane.

[0027] Optionally, the specific surface area of ​​the silica is 100 m². 2 / g-300m 2 / g.

[0028] Optionally, the silica is at least one of Aerosil R812, HDK H18, and H2000.

[0029] Introducing silica as a reinforcing filler can improve the damping performance of materials while maintaining their good mechanical properties. Silica, through its dynamic filler network and complex interfacial interactions with the matrix, enhances energy dissipation and damping performance at different strain stages through structural disruption, recombination, and molecular chain slippage.

[0030] According to a second aspect of the present invention, the present invention provides a method for preparing the addition-cure damping silicone rubber having a dual-mode network as described in any of the preceding claims, comprising the following steps: S1. Mix 100 parts of tetravinyl-terminated polysiloxane, 10-50 parts of silica, and 0.01-0.5 parts of catalyst evenly to obtain component A; Mix 50-90 parts of low-hydrogen-content terminal hydrogen silicone oil, 10-50 parts of high-hydrogen-content terminal hydrogen silicone oil, 10-50 parts of silica, and 0.01-0.5 parts of inhibitor evenly to obtain component B. S2 mixes components A and B evenly, pours the mixture into a mold, and cures it to obtain addition-cure damping silicone rubber.

[0031] Optionally, the vulcanization temperature in step S2 is 80-110℃ and the vulcanization time is 2-10h, thus obtaining the product.

[0032] According to a third aspect of the present invention, the present invention provides the use of the addition-cure damping silicone rubber having a dual-mode network as described in any of the preceding claims in the preparation of damping materials and / or damping devices.

[0033] Optionally, the damping material and / or damping device are used in aerospace, rail transportation and precision electronic equipment fields.

[0034] The beneficial effects of the present invention include, but are not limited to: 1. According to the present invention, tetravinyl-terminated polysiloxane and two types of hydrogen-terminated silicone oils with different hydrogen contents are selected as raw materials to ensure that the crosslinking reaction occurs only at the chain ends. This not only effectively avoids the uncertainty of the topological network caused by random crosslinking of side groups, but also provides the possibility of achieving controllable adjustment of the topological network and precise design of mechanical properties.

[0035] 2. According to the present invention, sterically hindered side groups such as ethyl, phenyl, and trifluoropropyl are introduced into the main molecular chain of tetravinyl-terminated polysiloxane to enhance the internal friction dissipation during molecular chain movement, thereby significantly improving the damping performance of silicone rubber.

[0036] 3. According to the present invention, tetravinyl-terminated polysiloxane undergoes a crosslinking reaction with various terminal hydrogen silicone oils of different molecular weights to form a bimodal network of interwoven long and short chains. During stress deformation, this network exhibits a multi-layered stress mechanism: when the high-hydrogen-content terminal hydrogen silicone oil (i.e., short chains) fails due to reaching its extension limit, the low-hydrogen-content terminal hydrogen silicone oil (i.e., long chains) with high conformational entropy is subsequently stretched to its ultimate orientation state. This induced orientation significantly enhances the interaction between molecular chains and the stress hardening effect, thereby enabling the silicone rubber to possess both high elongation, high tensile strength, and good toughness. Attached Figure Description

[0037] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the network of the addition-cure damping silicone rubber prepared in Comparative Example 1 and the embodiments of the present invention, wherein... Figure 1 (a) is a schematic diagram of the network of the addition-cure damping silicone rubber prepared in Comparative Example 1 of the present invention. Figure 1 (b) is a schematic diagram of the network of the addition-type damping silicone rubber prepared in Examples 1-6; Figure 2 The stress-strain curves of the silicone rubber prepared in the examples and comparative examples are shown. Detailed Implementation

[0038] The present invention will now be described in detail with reference to the embodiments, but the present invention is not limited to these embodiments.

[0039] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this invention were all purchased commercially.

[0040] Unless otherwise specified, the methods used in the embodiments and comparative examples of this invention are conventional methods in the prior art. The silica purchased and used in the embodiments and comparative examples of this invention is silica that has been treated with a fumed silica treatment agent to remove water.

[0041] Example 1 This embodiment relates to a method for preparing addition-cure damping silicone rubber with a dual-mode network, including the following steps: S1 mixes 100 parts of tetravinyl-terminated polysiloxane, 10 parts of Aerosil R812 silica, and 0.01 parts of tetramethyldivinyldisiloxane chloroplatinate complex (platinum concentration 1000 ppm) using a three-dimensional mixer, spinning it three times for 20 seconds each time at a speed of 1000 r / min to obtain component A, in which the silica has a specific surface area of ​​100 m². 2 / g; 85 parts of low-hydrogen-content terminal hydrogen silicone oil (0.005 wt%), 15 parts of high-hydrogen-content terminal hydrogen silicone oil (0.4 wt%), 10 parts of Aerosil R812 silica, and 0.4 parts of 1-ethynyl-1-cyclohexanol were mixed three times using a three-dimensional mixer, each time for 20 seconds at a speed of 1000 r / min, to obtain component B, in which the silica had a specific surface area of ​​200 m². 2 / g; S2 is prepared by mixing components A and B three times using a three-roll mill, removing air bubbles by vacuuming, and then vulcanizing at 80°C for 10 hours.

[0042] The preparation of tetravinyl-terminated polysiloxane includes the following steps: (1) Mix hexaethylcyclotrisiloxane and lithium hydroxide silanolate (base catalyst) accounting for 5% of the mass of hexaethylcyclotrisiloxane, heat to 50°C and distill under reduced pressure for 2 hours to obtain solution A; (2) Under a nitrogen atmosphere, add the capping agent 1,3-dimethyl-1,1,3,3-tetraethylenedisiloxane to solution A. The amount of capping agent added is 0.26% of the mass of solution A. The temperature is raised to 80℃ and reacted for 6 hours to obtain solution B. (3) After the solution B is cooled to room temperature under a nitrogen atmosphere, glacial acetic acid is added and the reaction is stirred for 2 hours to obtain solution C; (4) Heat solution C to 160℃ and distill under reduced pressure for 6 hours. Remove the solution under nitrogen atmosphere and bring it to room temperature.

[0043] The obtained tetravinyl-terminated polysiloxane has a vinyl content of 0.14 wt% and a diethyl chain number (z) of 784.

[0044] The structure of the obtained tetravinyl-terminated polysiloxane is as follows: .

[0045] Example 2 This embodiment relates to a method for preparing addition-cure damping silicone rubber with a dual-mode network, including the following steps: S1 mixes 100 parts of tetravinyl-terminated polysiloxane, 50 parts of HDK H18 silica, and 0.5 parts of isopropanol chloroplatinate solution (platinum concentration 5000 ppm) using a three-dimensional mixer, spinning it 5 times for 10 seconds each time at a speed of 2000 r / min to obtain component A, in which the silica has a specific surface area of ​​300 m². 2 / g; 90 parts of low-hydrogen-content terminal hydrogen silicone oil (0.02 wt%), 10 parts of high-hydrogen-content terminal hydrogen silicone oil (0.1 wt%), 50 parts of HDK H18 silica, and 0.4 parts of 2-methyl-3-butyn-2-ol were mixed in a three-dimensional mixer and spun five times, each time for 10 seconds at a speed of 2000 r / min, to obtain component B, in which the silica had a specific surface area of ​​300 m². 2 / g; S2 involves mixing components A and B five times using a three-roll mill, pouring the mixture into a polytetrafluoroethylene mold, removing air bubbles by vacuuming, and then curing it at 110°C for 2 hours to obtain the final product.

[0046] The preparation of tetravinyl-terminated polysiloxane includes the following steps: (1) Mix the second monomer and the third monomer, and 7% of the total mass of the second monomer and the third monomer, and then heat to 60°C and distill under reduced pressure for 0.5 h to obtain solution A, wherein the mass ratio of the second monomer and the third monomer is 1:1.25, the second monomer is selected from octaphenylcyclotetrasiloxane, and the third monomer is selected from hexaethylcyclotrisiloxane; (2) Under a nitrogen atmosphere, add the capping agent 1,3-dimethyl-1,1,3,3-tetraethylenedisiloxane to solution A. The amount of capping agent added is 0.70% of the mass of solution A. Heat to 120℃ and react for 3 hours to obtain solution B. (3) Solution B was cooled to room temperature under a nitrogen atmosphere, glacial acetic acid was added and the reaction was stirred for 1 hour to obtain solution C; (4) Heat solution C to 180℃ and distill under reduced pressure for 3 hours. Remove the solution under nitrogen atmosphere and bring it to room temperature.

[0047] The obtained tetravinyl-terminated polysiloxane has a vinyl content of 0.36 wt%, a diphenyl repeating unit number (y) of 81, and a methyltrifluoropropyl repeating unit number (z) of 81.

[0048] The structure of the obtained tetravinyl-terminated polysiloxane is as follows: .

[0049] Example 3 This embodiment relates to a method for preparing addition-cure damping silicone rubber with a dual-mode network, including the following steps: S1 mixes 100 parts of tetravinyl-terminated polysiloxane, 30 parts of H2000 silica, and 0.25 parts of tetramethyldivinyldisiloxane chloroplatinate complex (platinum concentration 3000 ppm) using a three-dimensional mixer, spinning it 5 times for 10 seconds each time at a speed of 2000 r / min to obtain component A, in which the silica has a specific surface area of ​​300 m². 2 / g; 80 parts of low-hydrogen-content terminal hydrogen silicone oil (0.015 wt%), 20 parts of high-hydrogen-content terminal hydrogen silicone oil (0.25 wt%), 30 parts of H2000 silica, and 0.3 parts of 2-methyl-3-butyn-2-ol were mixed in a three-dimensional mixer and spun five times, each time for 10 seconds at a speed of 2000 r / min, to obtain component B, in which the silica had a specific surface area of ​​300 m². 2 / g; S2 is prepared by mixing components A and B five times using a three-roll mill, pouring the mixture into a polytetrafluoroethylene mold, removing air bubbles by vacuuming, and then curing it at 110°C for 4 hours.

[0050] The preparation of tetravinyl-terminated polysiloxane includes the following steps: (1) Mix the first monomer, the second monomer, the third monomer, and cesium hydroxide (alkali catalyst) accounting for 10% of the total mass of the raw materials (first monomer, second monomer and third monomer), heat to 60°C and distill under reduced pressure for 1 hour to obtain solution A, wherein the mass ratio of the first monomer, the second monomer and the third monomer is 1:2.45:1.37, the first monomer is selected from hexamethylcyclotrisiloxane, the second monomer is selected from trimethyltriphenylcyclotrisiloxane, tetramethyltetraphenylcyclotetrasiloxane and pentamethylpentaphenylcyclopentasiloxane with a mass ratio of 1:4:2, and the third monomer is selected from hexaethylcyclotrisiloxane; (2) Under a nitrogen atmosphere, add the capping agent 1,3-dimethyl-1,1,3,3-tetraethylenedisiloxane to solution A. The amount of capping agent added is 0.38% of the mass of solution A. Heat to 100℃ and react for 5 hours to obtain solution B. (3) Solution B was cooled to room temperature under a nitrogen atmosphere, glacial acetic acid was added and the reaction was stirred for 1.5 h to obtain solution C; (4) Heat solution C to 170℃ and distill under reduced pressure for 5 hours. Remove the solution under nitrogen atmosphere and bring it to room temperature.

[0051] The obtained tetravinyl-terminated polysiloxane has a vinyl content of 0.20 wt%, a dimethyl chain number (x) of 153, a methylphenyl chain number (y) of 204, and a diethyl chain number (z) of 153.

[0052] The structure of the obtained tetravinyl-terminated polysiloxane is as follows: .

[0053] Example 4 This embodiment relates to a method for preparing addition-cure damping silicone rubber with a dual-mode network, including the following steps: S1 mixes 100 parts of tetravinyl-terminated polysiloxane, 30 parts of H2000 silica, and 0.1 parts of tetramethyltetravinylcyclotetrasiloxane chloroplatinate complex (platinum concentration 5000 ppm) using a three-dimensional mixer, spinning it 5 times for 10 seconds each time at a speed of 2000 r / min to obtain component A, in which the silica has a specific surface area of ​​300 m². 2 / g; 60 parts of low-hydrogen-content terminal hydrogen silicone oil (0.09 wt%), 40 parts of high-hydrogen-content terminal hydrogen silicone oil (0.3 wt%), 30 parts of H2000 silica, and 0.4 parts of 4-vinylpyridine were mixed in a three-dimensional mixer and spun five times, each time for 10 seconds at a speed of 2000 r / min, to obtain component B, in which the silica had a specific surface area of ​​300 m². 2 / g; S2 involves mixing components A and B five times using a three-roll mill, pouring the mixture into a polytetrafluoroethylene mold, removing air bubbles by vacuuming, and then curing it at 100°C for 6 hours to obtain the final product.

[0054] The preparation of tetravinyl-terminated polysiloxane includes the following steps: (1) Mix decamethylcyclopentasiloxane and potassium hydroxide silanolate (alkali catalyst) accounting for 8% of the mass of decamethylcyclopentasiloxane, heat to 60°C and distill under reduced pressure for 1 hour to obtain solution A; (2) Under a nitrogen atmosphere, add the capping agent 1,3-dimethyl-1,1,3,3-tetraethylenedisiloxane to solution A. The amount of capping agent added is 0.26% of the mass of solution A. Heat to 100℃ and react for 5 hours to obtain solution B. (3) Solution B was cooled to room temperature under a nitrogen atmosphere, glacial acetic acid was added and the reaction was stirred for 1.5 h to obtain solution C; (4) Heat solution C to 170℃ and distill under reduced pressure for 5 hours. Remove the solution under nitrogen atmosphere and bring it to room temperature.

[0055] The resulting tetravinyl-terminated polysiloxane has a vinyl content of 0.13 wt% and a dimethyl chain number (x) of 1100.

[0056] The structure of the obtained tetravinyl-terminated polysiloxane is as follows: .

[0057] Example 5 The difference between this embodiment and Embodiment 3 is that the preparation of the tetravinyl-terminated polysiloxane includes the following steps: (1) Mix the phenylsiloxane mixed ring and 9% by mass of potassium hydroxide siloxane (alkali catalyst), heat to 60°C and distill under reduced pressure for 1 h to obtain solution A, wherein the phenylsiloxane mixed ring is selected from trimethyltriphenylcyclotrisiloxane, tetramethyltetraphenylcyclotetrasiloxane and pentamethylpentaphenylcyclopentasiloxane in a mass ratio of 1:4:2; (2) Under a nitrogen atmosphere, add the capping agent 1,3-dimethyl-1,1,3,3-tetraethylenedisiloxane to solution A. The amount of capping agent added is 0.26% of the mass of solution A. Heat to 100℃ and react for 5 hours to obtain solution B. (3) Solution B was cooled to room temperature under an inert gas atmosphere, glacial acetic acid was added and the reaction was stirred for 1.5 h to obtain solution C; (4) Heat solution C to 170℃ and distill under reduced pressure for 5 hours. Remove the solution under nitrogen atmosphere and bring it to room temperature.

[0058] The obtained tetravinyl-terminated polysiloxane has a vinyl content of 0.13 wt% and a chain number (y) of methylphenyl of 588.

[0059] The structure of the obtained tetravinyl-terminated polysiloxane is as follows: .

[0060] Example 6 The difference between this embodiment and embodiment 3 is that the amount of capping agent added in step (2) is 1.05% of the mass of solution A, and the rest are the same.

[0061] Example 7 The difference between this embodiment and Embodiment 3 is that the hydrogen content of the high hydrogen content end-hydrogen silicone oil is 0.5 wt%.

[0062] Comparative Example 1 The difference between this comparative example and Example 3 is that 100 parts of high hydrogen content terminal hydrogen silicone oil (0.25 wt% hydrogen content) were used, and low hydrogen content terminal hydrogen silicone oil (0.015 wt% hydrogen content) was not added; all other aspects were the same.

[0063] Comparative Example 2 The difference between this comparative example and Example 3 is that a side-hydrogen silicone oil with a hydrogen content of 0.25 wt% is used instead of a high-hydrogen-content end-hydrogen silicone oil with a hydrogen content of 0.25 wt%, while all other aspects are the same.

[0064] Comparative Example 3 The difference between this comparative example and Example 3 is that in step (2), 1,1,3,3-tetramethyl-1,3-divinyldisiloxane is used instead of 1,3-dimethyl-1,1,3,3-tetraethylenedisiloxane to obtain a divinyl-terminated polysiloxane with a vinyl content of 0.19wt% instead of tetravinyl-terminated polysiloxane. All other aspects are the same.

[0065] Comparative Example 4 The difference between this comparative example and Example 3 is that the number of parts of low hydrogen content end-hydrogen silicone oil (0.015 wt% hydrogen content) is 40 parts, and the number of parts of high hydrogen content end-hydrogen silicone oil (0.25 wt% hydrogen content) is 60 parts, while the rest are the same.

[0066] Test case The mechanical properties of the addition-cure damping silicone rubber with dual-mode network prepared in the above embodiments and comparative examples were tested.

[0067] Figure 1 (a) is a schematic diagram of the network of the addition-cure damping silicone rubber prepared in Comparative Example 1 of the present invention. Figure 1 (b) is a schematic diagram of the network of the addition-type damping silicone rubber prepared in Examples 1-6. It can be seen from the schematic diagram that the present invention is a silicone rubber formed by a double network.

[0068] At room temperature, the tensile strength and elongation at break of silicone rubber were tested using a UTM4203X tensile testing machine (Shenzhen Sansi Zongheng Technology Co., Ltd.) according to GB / T 528-2009. Young's modulus, toughness, and flexibility were calculated using relevant formulas. The hardness of the silicone rubber was measured according to GB-T5311-2008. Damping performance was tested using a Metravib DMA+2000 dynamic thermomechanical analyzer. The test results are shown in Tables 1 and 2. Stress-strain curves for the examples and comparative examples are shown in [Table 1]. Figure 2 .

[0069] Table 1

[0070] Table 2

[0071] The test results for Comparative Examples 3 and 4 are indicated by "-" in Tables 1 and 2. This is because Comparative Example 3 involved a chain extension reaction between divinyl-terminated polysiloxane and hydrogen-terminated silicone oil, resulting in incomplete curing of the material and a gel-like sample, making it impossible to test its mechanical and damping properties. This demonstrates that only tetravinyl-terminated polysiloxane can be used to prepare the addition-type damping silicone rubber of this invention. In Comparative Example 4, a higher amount of high-hydrogen-content hydrogen-terminated silicone oil was used, also resulting in incomplete curing of the material and a gel-like sample, making it impossible to test its mechanical and damping properties.

[0072] A comparison of Examples 3 and 4 shows that introducing sterically hindered side groups such as ethyl, phenyl, or trifluoropropyl groups into the main chain of tetravinyl-terminated polysiloxane can significantly improve the damping performance of silicone rubber. The interaction between the large-volume side groups enhances the internal frictional resistance of molecular chain segment movement, increases the dissipation of mechanical energy within the silicone rubber, thereby increasing the loss factor and widening the effective damping temperature range of the silicone rubber.

[0073] A comparison between Example 3 and Example 6 shows that excessive addition of the end-capping agent resulted in a lower molecular weight of the tetravinyl-terminated polysiloxane. The room-temperature vulcanizing silicone rubber prepared in this way exhibited a higher crosslinking density, which restricted the movement of the molecular chains. Physical entanglement failed to effectively disperse stress through sliding, leading to a decrease in its mechanical strength and elongation at break.

[0074] A comparison of Examples 3 and 7 shows that increasing the hydrogen content of the high-hydrogen-content terminal hydrogen silicone oil means that the molecular chains of the terminal hydrogen silicone oil are shorter, the steric hindrance is smaller, and the probability of it colliding and reacting with tetravinyl-terminated polysiloxane is greatly increased. However, terminal hydrogen silicone oil with excessively short molecular chains will increase the crosslinking density of silicone rubber, resulting in an overly dense and unevenly distributed crosslinking network. This prevents stress from being effectively transferred between chain segments, thus causing a significant decrease in the tensile strength and elongation at break of the silicone rubber.

[0075] A comparison of Example 3 and Comparative Example 1 shows that when all the low-hydrogen-content end-hydrogen silicone oil is replaced with high-hydrogen-content end-hydrogen silicone oil, the resulting topological network is only a single network. When cracks occur, the cracks propagate rapidly because all chain segments have the same length, resulting in a significant decrease in the tensile strength and elongation at break of the silicone rubber.

[0076] A comparison of Example 3 and Comparative Example 2 shows that using side-hydrogen silicone oil with the same hydrogen content instead of high-hydrogen-content end-hydrogen silicone oil results in a change from a uniform network to a random network in the formed topological network. Under external force, the network structure formed by the side-hydrogen silicone oil is uncontrollable, and the short spacing between crosslinking points causes the chain segments to be rapidly stretched to their limits, preventing effective stress transfer. This leads to a significant decrease in the tensile strength and elongation at break of the silicone rubber. Because each molecule of the side-hydrogen silicone oil can connect to multiple vinyl reaction sites, the local crosslinking density of the silicone rubber increases, resulting in a significant increase in Shore hardness and Young's modulus.

[0077] The above description is merely an embodiment of the present invention, and the scope of protection of the present invention is not limited to these specific embodiments, but is determined by the claims of the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principle of the present invention should be included within the scope of protection of the present invention.

Claims

1. An addition-cure damping silicone rubber with a dual-mode network, characterized in that, Includes component A and component B; Component A, by weight, comprises 100 parts of tetravinyl-terminated polysiloxane, 10-50 parts of silica, and 0.01-0.5 parts of catalyst; Component B, by weight, comprises 50-90 parts of low-hydrogen-content terminal hydrogen silicone oil, 10-50 parts of high-hydrogen-content terminal hydrogen silicone oil, 10-50 parts of silica, and 0.01-0.5 parts of inhibitor. The high-hydrogen-content terminal hydrogen silicone oil has a hydrogen content of 0.1-0.5 wt%, and the low-hydrogen-content terminal hydrogen silicone oil has a hydrogen content of 0.001-0.09 wt%. The weight ratio of the high-hydrogen-content terminal hydrogen silicone oil to the low-hydrogen-content terminal hydrogen silicone oil is 1:(1-9). The catalyst is a platinum catalyst, and the inhibitor is an alkynyl alcohol inhibitor or a vinyl-containing inhibitor; The structure of the tetravinyl-terminated polysiloxane is shown in formula (I): Formula (I) R1 to R5 are independently selected from at least one of methyl, phenyl, ethyl, and trifluoropropyl, and 100 ≤ x + y + z ≤ 2000.

2. The addition-cure damping silicone rubber with a dual-mode network according to claim 1, characterized in that, The vinyl content of the tetravinyl-terminated polysiloxane is 0.05-0.5 wt%.

3. The addition-cure damping silicone rubber with a dual-mode network according to claim 1, characterized in that, R1 and R4 are independently selected from methyl and phenyl, and at least one of them is phenyl; R2 and R3 are independently selected from at least one of methyl, ethyl, and trifluoropropyl, and R2 and R3 are not both methyl; R5 is selected from methyl.

4. The addition-cure damping silicone rubber with a dual-mode network according to claim 1, characterized in that, The preparation method of the tetravinyl-terminated polysiloxane is as follows: (1) Mix a specific weight of the first monomer, the second monomer, the third monomer, and the alkaline catalyst according to the values ​​of x, y, and z, and heat to 50-60℃ for vacuum distillation to obtain solution A. The first monomer is selected from at least one of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane; the second monomer is selected from at least one of methylphenylsiloxane mixed ring, hexaphenylcyclotrisiloxane, or octaphenylcyclotetrasiloxane; and the third monomer is selected from hexaethylcyclotrisiloxane or methyltrifluoropropylcyclotrisiloxane. (2) Add the capping agent 1,3-dimethyl-1,1,3,3-tetraethylenedisiloxane to solution A under an inert gas atmosphere, heat to 80-120℃ and react for 3-6 hours to obtain solution B; (3) After the solution B is cooled to room temperature in an inert gas atmosphere, glacial acetic acid is added and the reaction is stirred for 1-2 hours to obtain solution C; (4) Distill solution C under reduced pressure and remove it at room temperature in an inert gas atmosphere to obtain tetravinyl-terminated polysiloxane.

5. The addition-cure damping silicone rubber with a dual-mode network according to claim 4, characterized in that, The alkaline catalyst in step (1) is selected from at least one of sodium hydroxide silanol, potassium hydroxide silanol, cesium hydroxide silanol, and lithium hydroxide silanol.

6. The addition-cure damping silicone rubber with a dual-mode network according to claim 4, characterized in that, The amount of alkaline catalyst added in step (1) is 1-10% of the mass of the cyclosiloxane monomer; The amount of capping agent added in step (2) is 0.1-1% of the mass of solution A.

7. The addition-cure damping silicone rubber with a dual-mode network according to claim 1, characterized in that, The catalyst is at least one of isopropanol chloroplatinate solution, tetramethyldivinyldisiloxane chloroplatinate complex, and tetramethyltetravinylcyclotetrasiloxane chloroplatinate complex, wherein the platinum content is 1000-5000 ppm by mass. The inhibitor is at least one of 1-ethynyl-1-cyclohexanol, 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, 4-vinylpyridine, and tetravinyltetramethylcyclotetrasiloxane.

8. A method for preparing the addition-cure damping silicone rubber with a dual-mode network according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Mix 100 parts of tetravinyl-terminated polysiloxane, 10-50 parts of silica, and 0.01-0.5 parts of catalyst evenly to obtain component A; Mix 50-90 parts of low-hydrogen-content terminal hydrogen silicone oil, 10-50 parts of high-hydrogen-content terminal hydrogen silicone oil, 10-50 parts of silica, and 0.01-0.5 parts of inhibitor evenly to obtain component B. S2 mixes components A and B evenly, pours the mixture into a mold, and cures it to obtain addition-cure damping silicone rubber.

9. The use of the addition-cure damping silicone rubber with a dual-mode network as described in any one of claims 1-7 in the preparation of damping materials and / or damping devices.

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