Silicone rubber damping agent and preparation method thereof

Abstract

The invention belongs to the technical field of silicone rubber materials, and particularly relates to a silicone rubber damping agent and a preparation method thereof. The silicone rubber damping agent is shown as a formula I, cyclodextrin is alpha-cyclodextrin, beta-cyclodextrin or gamma-cyclodextrin, the total number m of hydroxyl groups is 18, 21 or 24, and the modification number n meets the condition that n is larger than 0 and smaller than m. The preparation method comprises the following steps: mixing cyclodextrin, a solvent and an acid-binding agent, introducing inert gas to remove water, adding a phenylsilane compound, heating to react, and purifying. The silicone rubber damping agent can significantly improve the damping performance of silicone rubber in the range of-50 DEG C to 150 DEG C and maintain the mechanical property and low temperature resistance of the silicone rubber, and is suitable for the field I of wide-temperature-range vibration reduction.

Description

Technical Field

[0001] The invention belongs to the technical field of silicone rubber materials, and particularly relates to a silicone rubber damping agent and a preparation method thereof. Background Art

[0002] In the field of materials science, silicone rubber possesses exceptional molecular flexibility due to its unique molecular structure, characterized by a long Si-O bond length (approximately 1.64 Å) in the backbone and a wide range of Si-O-Si bond angles (130°–180°). Furthermore, the Si-O bond energy reaches 452 kJ / mol, far exceeding both C-C bonds (348 kJ / mol) and C-O bonds (358 kJ / mol). This gives silicone rubber excellent resistance to high and low temperatures, weathering, and chemical stability, leading to its widespread application in aerospace sealing components, electronic packaging insulation, and medical implants.

[0003] However, silicone rubber has significant shortcomings in terms of vibration damping. Due to the excessive flexibility of its molecular chains, its internal frictional energy dissipation is extremely low. It exhibits a high damping peak (tanδ of approximately 0.1-0.3) only within a narrow glass transition region (for example, the Tg of methyl silicone rubber is approximately -120°C to -130°C). This temperature range is far below the -50°C to 150°C range required for practical applications. Within the actual application temperature range, its damping performance is severely insufficient (tanδ is typically <0.1), making it difficult to meet the demand for high vibration damping across a wide temperature range. This significantly limits its further application in vibration control.

[0004] In order to broaden the application range of silicone rubber damping materials, researchers have made many attempts. The main methods are: (i) Blending modification: Blending silicone rubber with high-Tg rubber (such as nitrile rubber) or resin can broaden the damping temperature range, but due to the large difference in solubility parameters, phase separation is likely to occur, resulting in a decrease in the mechanical properties of the material; (ii) Phenyl silicone rubber modification: By introducing phenyl groups to increase the rigidity of the molecular chain, the Tg can be shifted to higher temperatures, but the increase in the damping peak is limited (tanδ is usually <0.2), and a high phenyl content can lead to increased brittleness of the material; (iii) Inorganic filler reinforcement: Adding fillers such as carbon black and graphene can improve damping through interfacial friction, but fillers tend to agglomerate, affecting dispersion uniformity and increasing processing difficulty; (iv) Interpenetrating network construction: The internal friction is increased by forming an organic-inorganic interpenetrating network, but the preparation process is complex (multi-step polymerization is required), the cost is high, and the network structure is difficult to control; (v) Addition of existing damping agents: Traditional damping agents (such as esters and amines) have poor compatibility with silicone rubber and are prone to migration and precipitation, resulting in the decay of damping performance over time.

[0005] Therefore, developing a damping agent that has excellent compatibility with silicone rubber, can significantly improve its damping performance in a wide temperature range, and does not damage other key properties has become a core requirement for solving the damping defects of silicone rubber.

[0006] Therefore, based on this, the technical solution of the present invention is proposed. Summary of the Invention

[0007] The present invention prepares a silicone rubber damping agent with cyclodextrin as the skeleton and triphenylsiloxy groups as the functional groups, which is used to enhance the damping performance of silicone rubber in a wide temperature range, so as to solve the defect of insufficient damping performance of silicone rubber in the actual application temperature range.

[0008] The present invention provides a silicone rubber damper, which is shown in Formula I:

[0009] Formula I Among them: the trapezoidal part on the left is the schematic structure of cyclodextrin; m is the number of hydroxyl groups in the cyclodextrin molecule, m = 18, 21 or 24; n is the number of triphenylsilyl groups modified on the cyclodextrin molecule, 0<n<m.

[0010] Preferably, the cyclodextrin is natural cyclodextrin or modified cyclodextrin; wherein: The cyclodextrins include but are not limited to α-cyclodextrin, β-cyclodextrin or γ-cyclodextrin; The α-cyclodextrin is shown in formula II; The β-cyclodextrin is represented by formula III; The γ-cyclodextrin is represented by formula IV; The modified cyclodextrin includes but is not limited to hydroxyalkylated cyclodextrin, alkylated cyclodextrin or acyloxylated cyclodextrin; The hydroxyalkylated cyclodextrin includes but is not limited to hydroxypropyl-β-cyclodextrin, hydroxyethyl-β-cyclodextrin or hydroxybutyl-β-cyclodextrin; The alkylated cyclodextrin includes but is not limited to methylated cyclodextrin or ethylated cyclodextrin; The acyloxylated cyclodextrin includes but is not limited to 2,3-diacetyl-β-cyclodextrin or 2,3,6-trihexanoyl-β-cyclodextrin. It should be emphasized that cyclodextrins with the same principle and similar structure as the present invention are within the scope of protection of the present invention.

[0011]

[0012] Formula II

[0013] Formula III

[0014] Formula IV.

[0015] To facilitate understanding of the present invention, the core mechanism by which the silicone rubber damper of the present invention functions is explained: Modified cyclodextrin molecules possess a structure that balances rigidity and flexibility. The rigid portion provides steric hindrance and friction, while the flexible portion provides intramolecular displacement (conformational changes, molecular vibrations, rotations, etc.), further increasing energy dissipation pathways. Cyclodextrin is a cyclic molecule composed of multiple D-pyranose glucose units. The D-pyranose glucose units are linked end-to-end by α-1,4-glycosidic bonds, with each D-pyranose glucose unit assuming a stable chair conformation. Because the rotational freedom of the α-1,4-glycosidic bonds is restricted, cyclodextrin molecules are not completely flexible cylinders, but rather conical rings. The chair conformation of the D-pyranose glucose units and the rigidity of the glycosidic bonds limit the overall molecule's ability to deform, making cyclodextrin a rigid molecule. Triphenylsiloxy groups are bulky and highly rigid, with long Si-O bonds (approximately 1.64 Å) and large Si-OC bond angles (130°-140°), imparting a certain degree of flexibility to the molecule. Modifying cyclodextrin molecules with triphenylsiloxy groups significantly increases steric hindrance and rigidity while also imparting a certain degree of flexibility. When such modified cyclodextrin molecules are dispersed in a polymer matrix, local obstacles to polymer chain motion increase. When the material is deformed by external forces, significant intermolecular friction occurs between the bulky triphenylsiloxy groups and the polymer chains, as well as between the groups themselves (via van der Waals forces and π-π interactions). This friction converts mechanical vibration energy (kinetic energy) into heat and dissipates it. Cyclodextrins are hydrophilic on the exterior and hydrophobic in the interior. Triphenylsiloxy modification connects the bulky, strongly hydrophobic triphenylsiloxy groups ((C6H5)3Si-O-) to the hydroxyl groups on the exterior surface of cyclodextrin. This greatly enhances the hydrophobicity of the cyclodextrin molecules and improves their compatibility with hydrophobic polymer matrices (such as silicone rubber, polyurethane, epoxy resin, and acrylic resin). Good compatibility is a prerequisite for effective damping. The multivalence of cyclodextrin (the presence of multiple reactive -OH groups) imparts tunable hydrophilic and hydrophobic properties, damping properties, and other material properties. By varying the molar ratio of triphenylsiloxy groups ((C6H5)3Si-O-) to cyclodextrin, a series of products with varying structures and properties can be obtained.

[0016] Based on the same technical concept, another solution of the present invention is to provide a method for preparing a silicone rubber damper, the preparation method comprising the following steps: (1) mixing cyclodextrin, a solvent, and an acid-binding agent to obtain a premix; (2) introducing a non-reactive gas into the premix to expel water vapor in the air, then adding a phenylsilane compound, and heating and stirring to react to obtain a reaction system; (3) Purifying the reaction system to obtain the silicone rubber damper.

[0017] Preferably, in step (1), the solvent includes but is not limited to one or a combination of two or more of dichloromethane, chloroform, tetrahydrofuran, toluene, and xylene.

[0018] Preferably, in step (1), the acid-binding agent includes but is not limited to one or a combination of two or more of triethylamine, N,N-diisopropylethylamine, N-methylmorpholine, 4-dimethylaminopyridine, 1,8-diazabicycloundec-7-ene, 1,5-diazabicyclo[4.3.0]non-5-ene, quinuclidine, and 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

[0019] Preferably, in step (2), the non-reactive gas includes but is not limited to an inert gas; the inert gas is nitrogen or argon; And / or, introduce non-reactive gas for 15 to 20 minutes to expel water vapor from the air.

[0020] Preferably, in step (2), the phenylsilane compound includes but is not limited to one of triphenylchlorosilane, diphenylmethylchlorosilane, and phenyldimethylchlorosilane.

[0021] Preferably, in step (2), the temperature of the heating and stirring reaction is 40-100°C, and the time of the heating and stirring reaction is 4-24 hours.

[0022] Preferably, in step (3), the purification method is: first filtering out the hydrochloride of the acid-binding agent, and then rotary evaporating the obtained filtrate to remove the solvent.

[0023] The beneficial effects of the present invention are: The silicone rubber damping agent provided by the present invention, which uses cyclodextrin as a skeleton and triphenylsiloxy groups as functional groups, can effectively solve the problem of insufficient damping performance of silicone rubber in the actual application temperature range (-50°C to 150°C), while maintaining its good mechanical properties and low-temperature resistance, thereby broadening the application range of silicone rubber in the field of damping and vibration reduction.

[0024] 1. Significantly improve the damping performance over a wide temperature range: After the damping agent is added to methyl silicone rubber, the loss factor increases from 0.040 to 0.254 at room temperature, from 0.025 to 0.210 at 80°C, and from 0.131 to 0.260 at -50°C. This comprehensively improves the damping effect of silicone rubber in the actual application temperature range and solves the defect of insufficient damping performance of the original silicone rubber.

[0025] 2. Maintain good mechanical properties: After adding the damping agent, the mechanical properties of silicone rubber, such as tensile strength and elongation at break, did not show obvious deterioration, and some indicators were even improved, overcoming the problem of decreased mechanical properties of materials caused by some modification methods.

[0026] 3. Maintain excellent low-temperature resistance: After adding the damping agent, the brittle temperature of silicone rubber is still below -65°C, retaining the original low-temperature resistance of silicone rubber and ensuring its normal use in low-temperature environments.

[0027] 4. Good compatibility with silicone rubber: The modification of triphenylsiloxy groups enhances the hydrophobicity of cyclodextrin molecules, significantly improving their compatibility with the hydrophobic silicone rubber matrix, avoiding the problem of poor compatibility affecting the damping effect, and providing a prerequisite for effective damping.

[0028] 5. Strong structural controllability: Cyclodextrin has multivalence (multiple reactive -OH groups). By changing the molar ratio of triphenylsiloxy groups to cyclodextrin, a series of products with different structures and properties can be obtained. The damping agent performance can be adjusted according to actual needs, and the applicability is wider. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 It is a schematic diagram of the molecular structure of silicone rubber damper.

[0031] Figure 2 This is the synthetic route of silicone rubber damping agent.

[0032] Figure 3 This is the infrared spectrum of "Dampener 7-1".

[0033] Figure 4 This is the infrared spectrum of β-cyclodextrin.

[0034] Figure 5 This is the infrared spectrum of triphenylchlorosilane. DETAILED DESCRIPTION

[0035] To make the objectives, technical solutions, and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other implementations obtained by those of ordinary skill in the art without inventive effort are within the scope of protection of the present invention.

[0036] Example 1 The present invention provides a method for preparing a silicone rubber damping agent, the preparation method comprising the following steps: (1) Raw material pretreatment: Dry β-cyclodextrin in a forced air oven at 105°C for 4 hours to remove moisture and prevent it from affecting subsequent reactions. Weigh 20.29 g (0.01788 mol) of the dried β-cyclodextrin for later use. Accurately weigh the mixture to ensure the correct reaction ratio.

[0037] Pre-dry the xylene solvent. Add an appropriate amount of anhydrous calcium chloride to the xylene, let it sit for 24 hours, then filter to remove moisture to prevent it from reacting with the reactants. Measure 150 mL of pre-dried xylene and set aside to ensure solvent purity to ensure a smooth reaction.

[0038] Weigh 12.79 g (0.1264 mol) of the acid-binding agent triethylamine and place it in a dry reagent bottle for later use. Accurately weigh it to neutralize the hydrochloric acid generated by the reaction.

[0039] (2) Preparation of premix: In a 500 mL dry, three-necked flask, add the weighed β-cyclodextrin, 150 mL of pre-dried xylene, and triethylamine, sequentially. Install a stirring device and stir thoroughly to form a uniform premix. This step disperses the cyclodextrin in the solvent and dissolves the acid-binding agent, preparing for the subsequent reaction.

[0040] (3) Remove water vapor and add reactants: Nitrogen was introduced into one port of the three-necked flask, and the other port was connected to the exhaust gas treatment device. The nitrogen flow rate was controlled at 1 to 2 bubbles per second and continued for 15 minutes to completely expel the water vapor in the air in the flask to prevent the water vapor from reacting with the phenylsilane compound.

[0041] Under nitrogen, slowly add 36.9 g (0.1251 mol) of triphenylsilyl chloride to the flask via a constant-pressure dropping funnel. The addition time is controlled over approximately 10 minutes to avoid localized high concentrations that could lead to an excessively vigorous reaction. This operation ensures that the reactants are added in an anhydrous environment, ensuring the reaction proceeds as expected.

[0042] (4) Heating and stirring reaction: Set up a heating apparatus and place the flask in an oil bath. Under nitrogen, raise the oil bath temperature to 80°C. Start stirring at 300 rpm and maintain this temperature and stirring rate for 6 hours. Heating increases the reaction rate, while stirring ensures full contact between the reactants and a uniform reaction.

[0043] (5) Purification treatment: After the reaction is completed, the heating device is turned off and the reaction system is allowed to cool naturally to room temperature to allow the hydrochloride of the acid binding agent to be fully precipitated.

[0044] Use a Buchner funnel to filter out the triethylamine hydrochloride solid generated by the reaction to obtain a clear filtrate. This step can remove reaction by-products and improve product purity.

[0045] The filtrate was transferred to a rotary evaporator, set at a water bath temperature of 60°C and a vacuum of 0.09 MPa, and the xylene solvent was removed by rotary evaporation to obtain the silicone rubber damping agent. Rotary evaporation can efficiently remove the solvent and obtain a relatively pure target product (i.e., silicone rubber damping agent).

[0046] In this example, since the molar ratio of triphenylsilyl chloride to β-cyclodextrin is 7:1, the silicone rubber damper obtained in this example is recorded as "damper 7-1".

[0047] In this embodiment, the molecular structure diagram of the silicone rubber damper is as follows: Figure 1 It should be clear that damping agent 7-1 is a mixture of a series of compounds with different substitution values. For the sake of convenience, Figure 1 The case where the substitution value is 7 was selected (in Example 2 below, n=14; in Example 3 below, n=21). Figure 2 same Figure 1 .

[0048] The synthetic route of silicone rubber damper is as follows: Figure 2 shown.

[0049] The infrared spectrum of "Dampener 7-1" is as follows Figure 3 shown.

[0050] The infrared spectrum of β-cyclodextrin is Figure 4 shown.

[0051] The infrared spectrum of triphenylchlorosilane is as follows Figure 5 shown.

[0052] Example 2 The present invention provides a method for preparing a silicone rubber damping agent, which comprises the following steps (brief description): (1) In a 500 mL flask, 13.75 g (0.1211 mol) of β-cyclodextrin dried in a forced air oven, 150 mL of pre-dried xylene solvent, and 17.33 g (0.1730 mol) of triethylamine (acid binding agent) were added to obtain a premix; (2) After nitrogen was passed through the flask for 15 minutes to remove water vapor in the air, 50.01 g (0.1696 mol) of triphenylsilyl chloride was added under nitrogen protection. The mixture was heated to 80 °C and stirred for 8 hours under nitrogen protection. (3) After the reaction is completed, the temperature is lowered to room temperature, the hydrochloride of the acid-binding agent is removed by filtration, and the filtrate is subjected to rotary evaporation to remove the solvent to obtain the silicone rubber damper.

[0053] In this embodiment, since the molar ratio of triphenylsilyl chloride to β-cyclodextrin is 14:1, the silicone rubber damper obtained in this embodiment is recorded as "damper 14-1".

[0054] Example 3 The present invention provides a method for preparing a silicone rubber damping agent, which comprises the following steps (brief description): (1) In a 500 mL flask, 9.17 g (0.008076 mol) of β-cyclodextrin dried in a forced air oven, 150 mL of pre-dried xylene solvent, and 17.33 g (0.1730 mol) of triethylamine (acid binding agent) were added to obtain a premix; (2) After nitrogen was passed through the flask for 15 minutes to remove water vapor in the air, 50.01 g (0.1696 mol) of triphenylsilyl chloride was added under nitrogen protection. The mixture was heated to 80 °C and stirred for 12 hours under nitrogen protection. (3) After the reaction is completed, the temperature is lowered to room temperature, the hydrochloride of the acid-binding agent is removed by filtration, and the filtrate is subjected to rotary evaporation to remove the solvent to obtain the silicone rubber damper.

[0055] In this embodiment, since the molar ratio of triphenylsilyl chloride to β-cyclodextrin is 21:1, the silicone rubber damper obtained in this embodiment is recorded as "damper 21-1".

[0056] Verification Example The relevant effects were verified by adding silicone rubber damping agent during the preparation of methyl silicone rubber, specifically: A raw methyl silicone rubber compound (100 parts) was mixed with fumed silica (33 parts), the curing agent di-tert-butyl peroxyisopropylbenzene (BIPB, 0.6 parts), and varying amounts of Damping Agent 7-1, Damping Agent 14-1, or Damping Agent 21-1 at room temperature on an open mill. The compound was then vulcanized at 170°C and 10 MPa for 10 minutes to produce damped methyl silicone rubber. The specific formulation is shown in Table 1.

[0057] Table 1 Silicone rubber formula with added damping agent

[0058] For comparison, a method for preparing methyl silicone rubber without adding a damping agent or adding unmodified β-cyclodextrin is provided, specifically: A raw methyl silicone rubber (100 parts) was mixed with fumed silica (33 parts), the curing agent di-tert-butyl peroxyisopropylbenzene (BIPB, 0.6 parts), and varying amounts of β-cyclodextrin at room temperature on an open mill. Subsequently, the rubber was vulcanized at 170°C and 10 MPa for 10 minutes to produce methyl silicone rubber without damping agent and with unmodified β-cyclodextrin. The specific formulations are shown in Table 2.

[0059] Table 2 Silicone rubber formula without damping agent and with 5 or 10 parts of β-cyclodextrin

[0060] The silicone rubber prepared by the above method was tested for hardness using a durometer, and its mechanical properties were evaluated using a tensile testing machine. Hardness was tested according to GB / T 531.1-2008, tensile strength and elongation at break were tested according to GB / T 528-2009, and tear strength was tested according to GB / T 529-2008. The test results are shown in Table 3.

[0061] Table 3 Test results of silicone rubber hardness and mechanical properties

[0062] Note: 5# and 6# formulations are not vulcanized, so there is no relevant data in this table.

[0063] As shown in Table 3, compared with the formula without damping agent (7#), the formulas (1# and 2#) with 5 or 10 parts of "Damping Agent 7-1" added showed a significant decrease in Shore A hardness and tear strength. The tear strength showed a downward trend with the addition of damping agent, while the tensile strength decreased less and the elongation at break increased significantly. Compared with the formula without damping agent (7#), the Shore A hardness of the formulas (3# and 4#) with 5 or 10 parts of "Damping Agent 14-1" remained unchanged or decreased by 2 degrees, with a small change. The tear strength showed a downward trend with the addition of damping agent, the tensile strength decreased significantly, and the elongation at break did not change much. Compared with the formula without damping agent (7#), the formulas with 5 or 10 parts of "Damping Agent 21-1" (5# and 6#) did not vulcanize. This is mainly because the triphenylchlorosilane molecules are large and rigid. Due to steric hindrance, a large number of them do not participate in the reaction. The unreacted triphenylchlorosilane molecules deactivate the free radicals, resulting in vulcanization failure. Compared with the formula without adding damping (7#): the formulas (8# and 9#) with adding 5 or 10 parts of unmodified β-cyclodextrin have improved Shore A hardness and tear strength. When adding 5 parts, the tensile strength and elongation at break do not change much. When adding 10 parts, the tensile strength and elongation begin to decrease.

[0064] The tensile strength of formula 3# and 4# decreased significantly, and formula 5# and 6# were not vulcanized, so these four formulas were not evaluated in the following tests.

[0065] The silicone rubber cylinders prepared by the above method were tested for dynamic and static stiffness and loss factor (tan δ) at room temperature, -50°C, and 80°C using an elastomer dynamic stiffness fatigue tester. Static and dynamic performance were tested according to the relevant test methods in GB / T 15168-2013. Static stiffness testing employed a loading rate of 80 N / s and a compressive force of 1500 N, ranging from 500 N to 1200 N. Dynamic stiffness testing employed a preload of 750 N, an amplitude of 0.30 mm, and a frequency of 16 Hz. The ellipse method was used for the test procedure and results calculation. Silicone rubber cylinders (40 mm diameter x 25 mm height) were prepared according to the formulations in Tables 1 and 2. Because the cylinders are much thicker than the sheets and therefore conduct heat more slowly, the pressing time for the cylinders was 10 minutes longer than for the sheets. The specific pressing conditions were 170°C, 10 MPa, and 20 minutes. The test results are shown in Table 4.

[0066] Table 4 Test results of silicone rubber static stiffness, dynamic stiffness and loss factor (tan δ)

[0067] As shown in Table 4, compared with the formula without damping agent (7#), the formula (1#) with 5 parts of damping agent 7-1 added has a room temperature loss factor of 0.192, which is increased by 380%; tan δ = 0.169 at a high temperature of 80°C, which is increased by 576%; and tan δ = 0.247 at a low temperature of -50°C, which is increased by 88.5%.

[0068] Compared with the formula without adding damping agent (7#), the formula (2#) with 10 parts of damping agent 7-1 added has a room temperature loss factor of 0.254, which is increased by 535%; tan δ = 0.210 at high temperature of 80 ℃, which is increased by 740%; and tan δ = 0.260 at low temperature of -50 ℃, which is increased by 98.5%.

[0069] Compared with the formula without damping agent (7#), the silicone rubber with 5 parts (8#) or 10 parts (9#) of β-cyclodextrin added has little change in loss factor at room temperature, -50°C and 80°C. The loss factor at room temperature and 80°C is still below 0.1.

[0070] The addition of the silicone rubber damping agent described herein, which uses a cyclodextrin backbone and triphenylsiloxy groups as functional groups, significantly enhances the wide-temperature damping performance of silicone rubber while maintaining good mechanical properties. The core mechanism of the damping agent's function is that the modified cyclodextrin molecules possess a structure that balances rigidity and flexibility: the rigid portion provides steric hindrance and friction, while the flexible portion facilitates intramolecular movement (conformational changes, molecular vibrations, rotations, etc.). The triphenylsiloxy groups are bulky and rigid, with long Si-O bonds (approximately 1.64 Å) and large Si-OC bond angles (130° to 140°), imparting a degree of flexibility to the molecule. Adding triphenylsiloxy groups to the cyclodextrin surface significantly increases the steric hindrance and rigidity of the cyclodextrin molecules. When these modified cyclodextrin molecules are dispersed in a polymer matrix, localized obstacles to the motion of the polymer chains are increased. When the material is deformed by external forces, significant intermolecular friction is generated between the bulky triphenylsiloxy groups and the polymer chains, as well as between the groups themselves (via van der Waals forces and π-π interactions). Under this frictional effect, mechanical vibration energy (kinetic energy) is converted into heat and dissipated. Cyclodextrin's inability to exert a damping effect is due to its polar outer surface, which weakens its interaction with the non-polar silicone rubber matrix. Furthermore, its molecules are highly rigid and lack flexible components to provide sufficient intramolecular displacement. When the material is deformed by external forces, the intermolecular friction is low, resulting in a poor ability to convert mechanical vibration into heat and dissipate it.

[0071] The brittle temperature of the silicone rubber prepared by the above method was tested using a rubber low-temperature brittleness tester according to GB / T 1682-2014. The test results are shown in Table 5.

[0072] Table 5 Silicone rubber brittle temperature test results

[0073] As shown in Table 5, when the addition amount of the damping agent 7-1 is 5 parts and 10 parts, the brittle temperature is lower than -65°C, indicating that the silicone rubber with the damping agent of the present invention maintains the excellent low-temperature resistance of the silicone rubber.

[0074] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A silicone rubber damper, characterized in that: The silicone rubber damping agent is shown in Formula I: Formula I Among them: the trapezoidal part on the left is the schematic structure of cyclodextrin; m is the number of hydroxyl groups in the cyclodextrin molecule, m = 18, 21 or 24; n is the number of triphenylsilyl groups modified on the cyclodextrin molecule, 0<n<m.

2. The silicone rubber damper according to claim 1, characterized in that: The cyclodextrin is natural cyclodextrin or modified cyclodextrin; wherein: The natural cyclodextrin is α-cyclodextrin, β-cyclodextrin or γ-cyclodextrin; The α-cyclodextrin is shown in formula II; The β-cyclodextrin is represented by formula III; The γ-cyclodextrin is represented by formula IV; The modified cyclodextrin is hydroxyalkylated cyclodextrin, alkylated cyclodextrin or acyloxylated cyclodextrin; The hydroxyalkylated cyclodextrin is hydroxypropyl-β-cyclodextrin, hydroxyethyl-β-cyclodextrin or hydroxybutyl-β-cyclodextrin; The alkylated cyclodextrin is methylated cyclodextrin or ethylated cyclodextrin; The acyloxylated cyclodextrin is 2,3-diacetyl-β-cyclodextrin or 2,3,6-trihexanoyl-β-cyclodextrin; Formula II Formula III Formula IV.

3. The method for preparing the silicone rubber damping agent according to claim 1 or 2, characterized in that: The preparation method comprises the following steps: (1) mixing cyclodextrin, a solvent, and an acid-binding agent to obtain a premix; (2) introducing a non-reactive gas into the premix to expel water vapor in the air, then adding a phenylsilane compound, and heating and stirring to react to obtain a reaction system; (3) Purifying the reaction system to obtain the silicone rubber damper.

4. The method for preparing the silicone rubber damping agent according to claim 3, characterized in that: In step (1), the solvent is one or a combination of two or more of dichloromethane, chloroform, tetrahydrofuran, toluene, and xylene.

5. The method for preparing the silicone rubber damping agent according to claim 3, characterized in that: In step (1), the acid-binding agent is one or a combination of two or more of triethylamine, N,N-diisopropylethylamine, N-methylmorpholine, 4-dimethylaminopyridine, 1,8-diazabicycloundec-7-ene, 1,5-diazabicyclo[4.3.0]non-5-ene, quinuclidine, and 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

6. The method for preparing the silicone rubber damping agent according to claim 3, characterized in that: In step (2), the non-reactive gas is an inert gas; the inert gas is nitrogen or argon; And / or, introduce non-reactive gas for 15 to 20 minutes to expel water vapor from the air.

7. The method for preparing the silicone rubber damping agent according to claim 3, characterized in that: In step (2), the phenylsilane compound is one of triphenylchlorosilane, diphenylmethylchlorosilane, and phenyldimethylchlorosilane.

8. The method for preparing the silicone rubber damping agent according to claim 3, characterized in that: In step (2), the temperature of the heating and stirring reaction is 40-100°C, and the time of the heating and stirring reaction is 4-24 hours.

9. The method for preparing the silicone rubber damping agent according to claim 3, characterized in that: In step (3), the purification method is: first filter out the hydrochloride of the acid-binding agent, and then evaporate the obtained filtrate to remove the solvent.

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