Low-modulus silicone rubber based on topological network regulation and preparation method and application thereof

Abstract

The application discloses a kind of low modulus silicone rubber based on topological network regulation and its preparation method and application, belong to room temperature vulcanized silicone rubber technical field.It includes component A, component B and component C;The A component, by weight fraction, includes tetraethenyl terminated polysiloxane 100 parts, white carbon black 10-50 parts, platinum catalyst 0.01-0.5 parts;The B component, by weight fraction, includes end hydrogen silicone oil 3-50 parts, tetraethenyl terminated polysiloxane 50-97 parts, white carbon black 10-50 parts, inhibitor 0.01-0.5 parts;The C component, by weight fraction, includes hydrogen-containing silicone resin 0-30 parts.The application controls the topological network of silicone rubber, reduces its modulus at the same time, makes it have better mechanical properties and damping performance, realizes the synergistic optimization of comprehensive performance.

Description

Technical Field

[0001] This invention relates to a low-modulus silicone rubber based on topological network regulation, its preparation method and application, belonging to the field of room temperature vulcanizing silicone rubber technology. Background Technology

[0002] With the rapid development of wearable electronic devices, medical sensors, electronic skin, and flexible and stretchable displays, the demand for elastomer materials that combine excellent mechanical properties with good flexibility is becoming increasingly urgent. Among many elastomer materials, silicone rubber, with its unique molecular structure, has become a key material for constructing high-performance flexible devices. Silicone rubber is... Si O Si With organic groups attached to the silicon atoms as the main chain, it exhibits excellent flexibility; Si The high bond energy of the O bond endows the material with excellent thermal stability, aging resistance and radiation resistance, enabling it to maintain reliable physical and chemical stability under complex working conditions.

[0003] Traditional room temperature vulcanizing (room temperature vulcanizing) silicone rubber formulations (such as patent CN121379169A) use side-chain hydrogen-containing silicone oil as a crosslinking agent to hydrosilylate with vinyl-terminated silicone oil, forming a typical random crosslinked network. These systems often rely on the physical filling of rigid fillers such as silica or MQ silicone resin to improve mechanical and damping properties, but this leads to a significant increase in material modulus with increasing filler content, making them unsuitable for applications such as flexible sensing. Formulation optimization (such as patent CN104531050B) can reduce the hardness of room temperature vulcanizing silicone rubber to 25 (Shore A), but this often comes at the cost of reduced mechanical strength, resulting in lower tensile strength and elongation at break, making it difficult to meet the requirements of flexible material applications.

[0004] Therefore, designing and preparing novel room-temperature silicone rubber materials with both low modulus and good mechanical properties by controlling the topological network structure of silicone rubber, so as to provide a reliable material basis for flexible electronics, soft robots and bio-integrated devices, has become an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a low-modulus silicone rubber based on topological network regulation. Tetravinyl-terminated polysiloxane is used as the matrix, which effectively reduces the initial modulus of the crosslinked network. At the same time, hydrogen-containing silicone resin is introduced into the crosslinked network to improve the geometric topology of the crosslinked network and increase intramolecular friction, thereby ensuring the damping performance of the material.

[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, the present invention provides a low-modulus silicone rubber based on topology network regulation, comprising component A, component B and component C; Component A, by weight, comprises 100 parts of tetravinyl-terminated polysiloxane, 10-50 parts of silica, and 0.01-0.5 parts of platinum catalyst. Component B, by weight, comprises 3-50 parts of hydrogen-terminated silicone oil, 50-97 parts of tetravinyl-terminated polysiloxane, 10-50 parts of silica, and 0.01-0.5 parts of inhibitor. The inhibitor is an alkynyl alcohol inhibitor or a vinyl-containing inhibitor; The C component, by weight, includes 0-30 parts of hydrogen-containing silicone resin; The structure of the tetravinyl-terminated polysiloxane is shown in formula (I):

[0007] Formula (I) Where x takes the value of an integer between 100 and 2000.

[0008] Preferably, x takes the value of an integer between 400 and 1100.

[0009] By optimizing the molecular network topology, a cross-linked elastic network with controllable cross-linking structure can be constructed by reacting tetravinyl-terminated polysiloxane with terminal hydrogen silicone oil. The uniform topology ensures stable stress transmission between molecular chains, effectively suppressing local stress concentration. Tetravinyl-terminated polysiloxane possesses high conformational entropy, which can impart high ductility and low initial modulus to the material. However, long chain segments are also limited by reaction kinetics, causing some end groups to fail to react. Therefore, introducing hydrogen-containing silicone resin as rigid cross-linking points not only provides physical reinforcement but also enables chemical cross-linking. The presence of these rigid cross-linking points improves the topological network, facilitating stress dispersion and synergistically working with the flexible network to improve the material's flexibility and mechanical strength.

[0010] By introducing hydrosilicone resin and silica as composite fillers, silicone rubber can maintain good mechanical properties while improving damping performance. Silica, through the formation of a dynamic filler network and complex interfacial interactions with the matrix, achieves efficient energy dissipation at different strain stages through structural disruption, recombination, and molecular chain slippage. Simultaneously, the hydrosilicone resin forms a dense three-dimensional network through covalent cross-linking, utilizing network deformation and intramolecular friction to store and dissipate energy.

[0011] Optionally, the vinyl content of the tetravinyl-terminated polysiloxane is 0.05-0.5 wt%; preferably 0.1-0.4 wt%.

[0012] Optionally, the preparation of the tetravinyl-terminated polysiloxane includes the following steps: (1) After mixing the cyclosiloxane monomer and the alkaline catalyst, heat to 50-60℃ and distill under reduced pressure for 2 hours to obtain solution A. The cyclosiloxane monomer is at least one of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane. (2) After adding the capping agent 1,3-dimethyl-1,1,3,3-tetraethylenedisiloxane to solution A under an inert gas atmosphere, carry out an equilibrium reaction at 80-120℃ for 3-6 hours to obtain solution B; (3) Heat solution B to 120-160℃ and continue the reaction for 1-2 hours to obtain solution C; (4) Heat solution C to 160-180℃ and distill under reduced pressure for 6 hours. Remove it at room temperature in an inert gas atmosphere to obtain tetravinyl-terminated polysiloxane.

[0013] This method enables the efficient polymerization of cyclosiloxane monomers under mild conditions, and allows for precise design of product viscosity and molecular chain length by adjusting the stoichiometric ratio of monomer to end-capping agent. Crucially, the catalyst used can be removed through thermal decomposition, avoiding complex post-processing steps and ensuring high chemical purity and thermal stability of the polymer. The advantages of this method in synthesizing polysiloxanes lie in its superior reaction kinetics, highly controllable molecular weight distribution, and excellent process operability.

[0014] Optionally, the alkaline catalyst in step (1) is at least one of tetramethylammonium methylsilyl alkoxide, tetramethylammonium hydroxide pentahydrate, and tetrabutylphosphine hydroxide.

[0015] Optionally, the amount of the alkaline catalyst added in step (1) is 0.01-1% of the mass of the cyclosiloxane monomer.

[0016] Optionally, the amount of capping agent added in step (2) is 0.1-1% of the mass of solution A, preferably 0.25-0.7%.

[0017] Optionally, the hydrogen-containing silicone resin is at least one of hydrogen-containing MQ silicone resin, hydrogen-containing POSS resin, hydrogen-containing MDT resin, and hydrogen-containing MDQ resin.

[0018] Optionally, the hydrogen content of the hydrogen-containing silicone resin is 0.1-1.8 wt%, preferably 0.25-0.7 wt%.

[0019] The hydrogen content of hydrogen-containing silicone resin is controlled between 0.25-0.7 wt% for a significant supplementary crosslinking effect. If the hydrogen content of the hydrogen-containing silicone resin is too high, a large number of silicon-hydrogen bonds will remain unreacted. These unreacted silicon-hydrogen bonds will slowly continue to react with moisture in the air, forming microbubbles inside the material, causing the sample surface to become sticky and significantly reducing the mechanical properties of the material. If the hydrogen content of the hydrogen-containing silicone resin is too low, the supplementary crosslinking degree will be insufficient, making it difficult to achieve the expected reinforcing effect.

[0020] Specifically, the hydrogen-containing MDT resin is obtained by reacting methyltrimethoxysilane, dimethyldimethoxysilane, tetramethyldisiloxane and trifluoromethanesulfonic acid at 90°C for 6 hours, washing with sodium bicarbonate aqueous solution until neutral, then rotary evaporating at 60°C to a viscous flow state, and finally drying in a vacuum oven.

[0021] Specifically, the hydrogen-containing MDQ resin is obtained by reacting tetraethyl silicate, dimethyldimethoxysilane, tetramethyldisiloxane and trifluoromethanesulfonic acid at 90°C for 6 hours, washing with sodium bicarbonate aqueous solution until neutral, then rotary evaporating at 60°C until it reaches a viscous flow state, and finally drying in a vacuum oven.

[0022] Optionally, the hydrogen content of the hydrogen-terminated silicone oil is 0.01-0.5 wt%.

[0023] Within this molecular weight range, all molecular chains in the system work together to bear external forces, significantly reducing stress concentration. This allows silicone rubber to maintain its low modulus properties while exhibiting good mechanical properties. If the hydrogen content of the terminal hydrogen silicone oil is too high, the crosslinking density of the system is too high, leading to a significant decrease in the mechanical properties of the silicone rubber. If the hydrogen content of the terminal hydrogen silicone oil is too low, the crosslinking density of the system is too low, and the steric hindrance effect reduces the reactivity of the end groups, resulting in an increase in the number of dangling chains, which in turn reduces the mechanical properties of the silicone rubber.

[0024] Optionally, the platinum catalyst is at least one of isopropanol chloroplatinate solution, tetramethyltetravinylcyclotetrasiloxane platinum complex (68585-32-0), and divinyltetramethyldisiloxane platinum complex (68478-92-2), wherein the mass concentration of platinum is 1000-5000 ppm.

[0025] Specifically, the mass ratio of chloroplatinic acid to isopropanol in the chloroplatinic acid isopropanol solution is 1:(50-100).

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

[0027] Optionally, the vinyl-containing inhibitor is 4-vinylpyridine or tetravinyltetramethylcyclotetrasiloxane.

[0028] Optionally, the specific surface area of ​​the silica is 100 m². 2 / g-300m 2 / g.

[0029] According to a second aspect of the present invention, the present invention provides a method for preparing low-modulus silicone rubber based on topology network control as described in any of the preceding claims, comprising the following steps: S1 involves uniformly mixing tetravinyl-terminated polysiloxane, silica, and platinum catalyst to obtain component A. Hydrogen-terminated silicone oil, tetravinyl-terminated polysiloxane, silica, and inhibitor are mixed evenly to obtain component B. S2: Mix components A and B thoroughly, let stand for 4-10 hours, then add component C, mix thoroughly, pour into a mold and cure to obtain low-modulus silicone rubber. When the amount of hydrosilicone resin is 0 parts, component C is not added.

[0030] The three-component room-temperature vulcanizing silicone rubber system obtained by the above preparation method exhibits good storage stability in its unmixed state, allowing for long-term storage without gelation. During the curing process, the sequence of mixing component A and component B first, followed by adding component C, not only simplifies the operation and improves process feasibility but also effectively optimizes the topology of the crosslinked network. This method achieves a low modulus in silicone rubber while ensuring that mechanical and damping properties do not significantly decrease, thus achieving a good balance between flexibility and functionality.

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

[0032] Optionally, the mixing operation in step S1 is to use a three-dimensional mixer to spin 3-8 times, each time for 10-50 seconds, at a speed of 1000-3000 r / min.

[0033] Optionally, the mixing operation in step S2 is to mix 3-10 times using a three-roll mill.

[0034] According to a third aspect of the present invention, the present invention provides the application of the low-modulus silicone rubber based on topology network control as described in any of the above claims, or the low-modulus silicone rubber prepared by the above-described method for preparing low-modulus silicone rubber based on topology network control, in the fabrication of flexible devices.

[0035] Optionally, the applications include wearable electronic devices, medical sensors, electronic skin, soft robots, and flexible stretchable displays.

[0036] The beneficial effects of the present invention include, but are not limited to: 1. According to the present invention, a covalent cross-linking system with uniformly dispersed cross-linking points is constructed by hydrosilylation reaction of tetravinyl-terminated polysiloxane and hydrogen-terminated silicone oil. As a long-chain cross-linking structure, tetravinyl-terminated polysiloxane ensures that the silicone rubber possesses a low modulus while improving its mechanical properties, overcoming the limitation of traditional silicone rubber in achieving a balance between strength and modulus.

[0037] 2. According to the present invention, the introduction of hydrogen-containing silicone resin can give full play to its dual function as an active crosslinking agent and a reinforcing filler. When the material is deformed under stress, the rigid resin molecules embedded in the flexible crosslinking network can ensure uniform stress distribution and generate huge internal friction with the moving flexible chain segments, converting mechanical energy into heat energy dissipation, thereby improving the mechanical properties and damping properties of silicone rubber.

[0038] 3. According to the present invention, the prepared three-component room temperature vulcanizing silicone rubber not only can be stored for a long time without gelation, but also optimizes the topology of the crosslinked network. This method enables the silicone rubber to maintain a low modulus while possessing good mechanical and damping properties, thus achieving a good balance between flexibility and functionality. Attached Figure Description

[0039] 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 uniform crosslinked topology of the low-modulus silicone rubber prepared in Examples 4 and 3 of the present invention; Figure 2 The stress-strain curves of the low-modulus silicone rubber prepared in the embodiments and comparative examples of the present invention are shown. Detailed Implementation

[0040] The present invention will now be described in detail with reference to the embodiments, but the present invention is not limited to these embodiments.

[0041] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this invention were all purchased commercially.

[0042] 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.

[0043] Example 1 This embodiment relates to a method for preparing low-modulus silicone rubber based on topological network control, including the following steps: S1 mixes 100 parts of tetravinyl-terminated polysiloxane, 50 parts of silica, and 0.01 parts of isopropanol chloroplatinic acid solution (chloroplatinic acid to isopropanol mass ratio 1:50, platinum mass concentration 1000 ppm) using a three-dimensional mixer, spinning it 5 times for 20 seconds each time at a speed of 1000 r / min to obtain component A, in which the specific surface area of ​​silica is 200 m². 2 / g; Component B was obtained by mixing 50 parts of hydrogen-terminated silicone oil (0.038 wt% hydrogen content), 50 parts of tetravinyl-terminated polysiloxane, 50 parts of silica, and 0.1 parts of 1-ethynyl-1-cyclohexanol five times in a three-dimensional mixer, each time for 20 seconds at a speed of 1000 r / min. The silica in this mixture had a specific surface area of ​​100 m². 2 / g; S2: Mix components A and B three times using a three-roll mill, let stand at room temperature for 4 hours, then add 30 parts of hydrogen-containing POSS resin with a hydrogen content of 0.68 wt%, mix three times again using a three-roll mill, pour into a polytetrafluoroethylene mold, remove air bubbles by vacuuming, and cure at 80°C for 10 hours to obtain the final product.

[0044] The preparation of tetravinyl-terminated polysiloxane includes the following steps: (1) Mix 0.01% by mass of octamethylcyclotetrasiloxane with tetramethylammonium hydroxide pentahydrate and heat to 50°C for vacuum distillation 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 0.70% of the mass of solution A. Heat to 80℃ and react for 6 hours to obtain solution B. (3) Heat solution B to 120℃ and continue the reaction for 2 hours to obtain solution C; (4) Heat solution C to 160°C and distill under reduced pressure for 6 hours. Remove the solution under nitrogen atmosphere and bring it to room temperature to obtain tetravinyl-terminated polysiloxane.

[0045] The obtained tetravinyl-terminated polysiloxane has a vinyl content of 0.36 wt%.

[0046] The structural formula of the obtained tetravinyl-terminated polysiloxane is:

[0047] Where x is 402.

[0048] Example 2 This embodiment relates to a method for preparing low-modulus silicone rubber based on topological network control, including the following steps: S1 mixes 100 parts of tetravinyl-terminated polysiloxane, 10 parts of silica, and 0.5 parts of tetramethyltetravinylcyclotetrasiloxane platinum complex (platinum concentration 5000 ppm) using a three-dimensional mixer, spinning it 8 times for 10 seconds each time at a speed of 2000 r / min to obtain component A, in which the specific surface area of ​​silica is 300 m². 2 / g; Component B was obtained by mixing 3 parts of hydrogen-terminated silicone oil (0.3 wt% hydrogen content), 97 parts of tetravinyl-terminated polysiloxane, 10 parts of silica, and 0.5 parts of 2-methyl-3-butyn-2-ol in a three-dimensional mixer for 8 cycles, each cycle lasting 10 seconds at a speed of 2000 r / min. The silica in this mixture had a specific surface area of ​​300 m². 2 / g; S2: Mix components A and B 10 times using a three-roll mill, let stand at room temperature for 10 hours, then add 2 parts of hydrogen-containing MQ resin with a hydrogen content of 0.45wt%, mix again using a three-roll mill 10 times, pour into a polytetrafluoroethylene mold, remove air bubbles by vacuuming, and cure at 110℃ for 2 hours to obtain the final product.

[0049] The preparation of tetravinyl-terminated polysiloxane includes the following steps: (1) Add 1% of tetramethylammonium hydroxide silanolate of the total mass of hexamethylcyclotrisiloxane to hexamethylcyclotrisiloxane, heat to 60°C and distill under reduced pressure for 0.5 h 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 120℃ and react for 3 hours to obtain solution B. (3) Heat solution B to 160℃ and continue the reaction for 1 hour to obtain solution C; (4) Heat solution C to 180°C and distill under reduced pressure for 3 hours. Remove the solution under nitrogen atmosphere and bring it to room temperature to obtain tetravinyl-terminated polysiloxane.

[0050] The obtained tetravinyl-terminated polysiloxane has a vinyl content of 0.14 wt%.

[0051] The structural formula of the obtained tetravinyl-terminated polysiloxane is:

[0052] Where x is 1078.

[0053] Example 3 This embodiment relates to a method for preparing low-modulus silicone rubber based on topological network control, including the following steps: S1 mixes 100 parts of tetravinyl-terminated polysiloxane, 30 parts of silica, and 0.25 parts of divinyltetramethyldisiloxane platinum complex (platinum concentration 3000 ppm) using a three-dimensional mixer, spinning it three times for 50 seconds each time at a speed of 3000 r / min to obtain component A, in which the specific surface area of ​​silica is 300 m². 2 / g; Component B was obtained by mixing 40 parts of hydrogen-terminated silicone oil (0.038 wt% hydrogen content), 60 parts of tetravinyl-terminated polysiloxane, 30 parts of silica, and 0.3 parts of 2-methyl-3-butyn-2-ol three times using a three-dimensional mixer, each time for 50 seconds at a speed of 3000 r / min. The silica in this mixture had a specific surface area of ​​300 m². 2 / g; S2: Mix components A and B five times using a three-roll mill, let stand at room temperature for 6 hours, then add 5 parts of hydrogen-containing MQ silicone resin with a hydrogen content of 0.28 wt%, mix five times again using a three-roll mill, pour into a polytetrafluoroethylene mold, remove air bubbles by vacuuming, and cure at 110℃ for 4 hours to obtain the final product.

[0054] The preparation of tetravinyl-terminated polysiloxane includes the following steps: (1) Add 0.04% of the mass of tetramethylammonium hydroxide pentahydrate to hexamethylcyclotrisiloxane, heat to 60°C and distill under reduced pressure for 1 h 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 0.38% of the mass of solution A. Heat to 100℃ and react for 5 hours to obtain solution B. (3) Heat solution B to 140℃ and continue the reaction for 1.5 h to obtain solution C; (4) Heat solution C to 170°C and distill under reduced pressure for 5 hours. Remove the solution under nitrogen atmosphere and bring it to room temperature to obtain tetravinyl-terminated polysiloxane.

[0055] The obtained tetravinyl-terminated polysiloxane has a vinyl content of 0.20 wt%.

[0056] The structural formula of the obtained tetravinyl-terminated polysiloxane is:

[0057] Where x is 740.

[0058] Example 4 This embodiment relates to a method for preparing low-modulus silicone rubber based on topological network control, including the following steps: S1 mixes 100 parts of tetravinyl-terminated polysiloxane, 30 parts of silica, and 0.1 parts of isopropanol chloroplatinic acid solution (chloroplatinic acid to isopropanol mass ratio 1:100, platinum mass 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 specific surface area of ​​silica is 300 m². 2 / g; Five parts of hydrogen-terminated silicone oil with a hydrogen content of 0.5%, 95 parts of tetravinyl-terminated polysiloxane, 30 parts of silica, and 0.2 parts of 4-vinylpyridine were mixed three times using a three-dimensional mixer, each time for 10 seconds at a speed of 3000 r / min, to obtain component B, in which the specific surface area of ​​silica was 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.

[0059] The preparation steps for tetravinyl-terminated polysiloxane are the same as in Example 3.

[0060] Example 5 The difference between this embodiment and Embodiment 4 is that the hydrogen content of the hydrogen-terminated silicone oil is 0.6 wt%, while the rest are the same.

[0061] Example 6 The difference between this embodiment and Embodiment 3 is that the hydrogen-containing MQ silicone resin is replaced with hydrogen-free methyl MQ silicone resin, while the rest are the same.

[0062] Example 7 The difference between this embodiment and embodiment 4 is that the amount of capping agent added in step (2) is 1.05% of the mass of solution A, while the rest are the same.

[0063] Comparative Example 1 The difference between this comparative example and Example 4 is that the hydrogen-terminated silicone oil in component B is 90 parts, and the tetravinyl-terminated polysiloxane is 10 parts, while the rest are the same.

[0064] Comparative Example 2 The difference between this comparative example and Example 3 is that component C is added in step S2, but not in step S3; all other aspects are the same.

[0065] Comparative Example 3 The difference between this comparative example and Example 4 is that side-hydrogen silicone oil (containing 0.4 wt% hydrogen) is used instead of end-hydrogen silicone oil; all other aspects are the same.

[0066] Comparative Example 4 The difference between this comparative example and Example 4 is that divinyl-terminated polysiloxane is used instead of tetravinyl-terminated polysiloxane in components A and B: in step (2), 1,1,3,3-tetramethyl-1,3-divinyldisiloxane is used instead of 1,3-dimethyl-1,1,3,3-tetravinyldisiloxane to obtain divinyl-terminated polysiloxane, and side-hydrogen silicone oil (containing 0.4 wt% hydrogen) is used instead of terminal hydrogen silicone oil, and the rest are the same.

[0067] Test case At room temperature, the tensile strength and elongation at break of the silicone rubbers prepared in the above examples and comparative examples 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 according to 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. Figure 2 The diagrams of the crosslinked topology of the low-modulus silicone rubbers prepared in Examples 3 and 4 are provided, and the results are obtained. Figure 1 .

[0068] Table 1

[0069] Table 2

[0070] The test results for Comparative Example 1 are indicated by "-" in Tables 1 and 2. This is because the amount of hydrogen-terminated silicone oil used in Comparative Example 1 was too large, resulting in the material not being able to completely cure, and the prepared sample was in a gel state, making it impossible to test its mechanical and damping properties.

[0071] refer to Figure 1 The low-modulus silicone resin prepared by this invention has a uniform topological network, as shown in Tables 1 and 2. Figure 2 The results show that: As can be seen from Examples 3 and 4, and Comparative Examples 3 and 4, when the topological network of room temperature vulcanizing silicone rubber changes from a random network to a uniform network formed by tetravinyl-terminated polysiloxane and hydrogen-terminated silicone oil, its hardness and Young's modulus decrease significantly, while its tensile strength, elongation at break, toughness, and flexibility show an increasing trend. This is because the uniformly cross-linked topological structure ensures the uniform transmission of stress between molecular chains, effectively suppressing stress concentration; at the same time, the higher conformational entropy brought by the long chain segments endows the material with high ductility and low modulus. This uniformly cross-linked topological network allows silicone rubber to maintain a low modulus while possessing good mechanical properties.

[0072] As can be seen from Examples 3 and 4, with the addition of hydrosilicone resin, the hardness of room temperature vulcanized silicone rubber increases and its damping performance improves, but its tensile strength, elongation at break, and toughness decrease slightly. This is because the hydrosilicone resin, as a rigid crosslinking point, not only plays a physical reinforcing role but also achieves chemical crosslinking. The presence of these rigid crosslinking points makes the topological network more complete, and its synergistic effect with the flexible network improves energy dissipation through network deformation and intramolecular friction. At the same time, the addition of hydrosilicone resin increases the crosslinking density of the system to a certain extent, leading to a decrease in the tensile properties and elongation at break of the material. However, the silicone rubber can still maintain a low modulus and good tensile properties, and exhibit good damping performance.

[0073] Furthermore, as can be seen from Example 3 and Comparative Example 2, the silicone rubber prepared by introducing hydrogen-containing silicone resin in a stepwise manner exhibits superior mechanical strength, elongation at break, and toughness compared to the one-step addition method. This is because the stepwise addition of hydrogen-containing silicone resin allows the tetravinyl-terminated polysiloxane to preferentially react with the terminal hydrogen silicone oil, forming a topological network with a more uniform distribution of crosslinking points, thereby avoiding the influence of adding hydrogen-containing silicone resin on the uniform crosslinking topological network.

[0074] The comparison of Examples 1-6 shows that increasing the proportions of silica and hydrosilicone resin can effectively improve the maximum damping factor of room temperature vulcanizing silicone rubber. This is because the hydrosilicone resin increases the crosslinking density through covalent crosslinking, enabling energy dissipation through network deformation and intramolecular friction; while silica dissipates energy through structural destruction, recombination, and molecular chain slippage at different strain stages by forming a filler network and interfacial interactions with the matrix.

[0075] The silicone rubber prepared by this invention still has good damping and mechanical properties at low modulus, meeting the application requirements under complex working conditions. It can be applied to wearable electronic devices, medical sensors, electronic skin, and flexible and stretchable displays. The process is simple and has broad market prospects.

[0076] 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. A low-modulus silicone rubber based on topology network regulation, characterized in that, Includes components A, B, and C; Component A, by weight, comprises 100 parts of tetravinyl-terminated polysiloxane, 10-50 parts of silica, and 0.01-0.5 parts of platinum catalyst. Component B, by weight, comprises 3-50 parts of hydrogen-terminated silicone oil, 50-97 parts of tetravinyl-terminated polysiloxane, 10-50 parts of silica, and 0.01-0.5 parts of inhibitor. The hydrogen content of the hydrogen-terminated silicone oil is 0.01-0.5 wt%. The inhibitor is an alkynyl alcohol inhibitor or a vinyl-containing inhibitor; The C component, by weight, includes 0-30 parts of hydrogen-containing silicone resin; The hydrogen content of the hydrogen-containing silicone resin is 0.1-1.8 wt%; The structure of the tetravinyl-terminated polysiloxane is shown in formula (I): Formula (I) Where x takes the value of an integer between 100 and 2000; The method for preparing low-modulus silicone rubber based on topology network control includes the following steps: S1 involves uniformly mixing tetravinyl-terminated polysiloxane, silica, and platinum catalyst to obtain component A. Hydrogen-terminated silicone oil, tetravinyl-terminated polysiloxane, silica, and inhibitor are mixed evenly to obtain component B. S2 mixes components A and B evenly, lets stand for 4-10 hours, then adds component C, mixes evenly, pours into a mold and cures to obtain low-modulus silicone rubber; when the amount of hydrogen-containing silicone resin is 0 parts, component C is not added.

2. The low-modulus silicone rubber based on topology network regulation according to claim 1, characterized in that, The vinyl content of the tetravinyl-terminated polysiloxane is 0.05-0.5 wt%.

3. The low-modulus silicone rubber based on topology network control according to claim 1, characterized in that, The preparation method of the tetravinyl-terminated polysiloxane includes the following steps: (1) After mixing the cyclosiloxane monomer and the alkaline catalyst, heat to 50-60℃ and distill under reduced pressure for 2 hours to obtain solution A. The cyclosiloxane monomer is at least one of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane. (2) After adding the end-capping agent 1,3-dimethyl-1,1,3,3-tetraethylenedisiloxane to solution A under an inert gas atmosphere, the reaction is balanced at 80-120℃ for 3-6 hours to obtain solution B; (3) Heat solution B to 120-160℃ and continue the reaction for 1-2 hours to obtain solution C; (4) After heating solution C to 160-180℃ and distilling under reduced pressure for 6 hours, remove it from the room temperature under an inert gas atmosphere to obtain tetravinyl-terminated polysiloxane.

4. The low-modulus silicone rubber based on topology network regulation according to claim 3, characterized in that, The alkaline catalyst mentioned in step (1) is at least one of tetramethylammonium methylsilyl alkoxide, tetramethylammonium hydroxide pentahydrate, and tetrabutylphosphine hydroxide; The amount of the alkaline catalyst added is 0.01-1% of the mass of the cyclosiloxane monomer.

5. The low-modulus silicone rubber based on topology network control according to claim 3, characterized in that, The amount of capping agent added in step (2) is 0.1-1% of the mass of solution A.

6. The low-modulus silicone rubber based on topology network control according to claim 1, characterized in that, The hydrogen-containing silicone resin is at least one of hydrogen-containing MQ silicone resin, hydrogen-containing POSS resin, hydrogen-containing MDT resin, and hydrogen-containing MDQ resin.

7. The low-modulus silicone rubber based on topology network control according to claim 1, characterized in that, The platinum catalyst is at least one of isopropanol chloroplatinate solution, tetramethyltetravinylcyclotetrasiloxane platinum complex, and divinyltetramethyldisiloxane platinum complex, wherein the mass concentration of platinum is 1000-5000 ppm. The alkynol inhibitor is at least one of 1-ethynyl-1-cyclohexanol, 2-methyl-3-butyn-2-ol, and 3,5-dimethyl-1-hexyn-3-ol; The vinyl-containing inhibitor is 4-vinylpyridine or tetravinyltetramethylcyclotetrasiloxane.

8. The application of the low-modulus silicone rubber based on topology network control as described in any one of claims 1-7 in the fabrication of flexible devices.

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