Sliding ring damping material containing free suspension chain and preparation method thereof

Abstract

The invention provides a slip ring damping material containing a free suspension chain and a preparation method of the slip ring damping material, and relates to the technical field of damping materials. The damping material comprises the following components in parts by weight: 10-80 parts of silicone oil, 20-90 parts of modified polyrotaxane and 0.2-9 parts of a cross-linking agent, and the modified polyrotaxane is prepared by reacting vinyl-terminated polydimethylsiloxane with gamma-cyclodextrin and then modifying with anhydride. The damping material is obtained by irradiation crosslinking of silicone oil, modified polyrotaxane and a crosslinking agent under gamma rays. Silicone oil fluid is grafted on a modified polyrotaxane sliding ring through irradiation of gamma rays, namely a suspension chain is grafted on the sliding ring, the middle part of the silicone oil fluid is restrained on the sliding ring, the two ends of the silicone oil fluid are free and can slide better, the suspension chain brings friction along with sliding of the sliding ring, and an excellent damping effect is achieved. The loss factor of the damping material can be effectively improved, and the damping peak value of the damping material is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of damping materials, and more particularly, to a sliding ring damping material containing free hanging chains and a preparation method thereof. Background Art

[0002] Polymer-based damping materials, due to their unique viscoelasticity, can convert part of the mechanical energy into heat energy under the action of external stress, and can effectively reduce the harm of noise and vibration. They have become the most widely used damping, vibration reduction and noise reduction materials.

[0003] Patent CN113999609 A discloses a polyurethane / epoxy sliding ring damping coating, which includes the following raw material components: 6-10 parts of polyurethane, 1-5 parts of epoxy resin, 2-10 parts of polyrotaxane, and 0.02-0.05 parts of curing agent; adding polyrotaxane to polyurethane epoxy resin, the cross-linking points of the polyrotaxane and the network molecular backbone can slide, and part of the molecular chains slide along with the sliding ring on the main molecular chain. This part of the sliding brings sliding friction, improves the loss factor, and achieves a high damping effect. However, during the experimental research process, it was found that the segments of the polyurethane chains grafted on the sliding rings are not free chains, but constrained chains with chemical bonds at both ends. The sliding of the segments is not sufficient, the friction is small, and the viscoelastic properties are damaged due to the chemical bonds fixed at both ends. The obtained damping material has a poor loss factor, a low damping peak, and a poor damping effect. Summary of the Invention

[0004] The purpose of the present invention is to provide a sliding ring damping material containing free hanging chains, which has a high loss factor, improves the damping peak of the damping material, and has excellent damping effect.

[0005] Another purpose of the present invention is to provide a preparation method of a sliding ring damping material containing free hanging chains, which can graft silicone oil fluid onto the cyclodextrin of modified polyrotaxane to form free-sliding hanging chains at both ends. This not only prevents the precipitation and migration of silicone oil fluid, but also due to the freedom and slidability of both ends of the molecular chain, the material has sufficient viscoelastic properties to broaden the temperature range, and can also enhance the sliding friction to improve the loss factor and enhance the damping effect.

[0006] The present invention is achieved through the following technical solutions:

[0007] A sliding ring damping material containing free hanging chains, the damping material includes, by weight, 10-80 parts of silicone oil, 20-90 parts of modified polyrotaxane, and 0.2-9 parts of cross-linking agent. The modified polyrotaxane is prepared by reacting vinyl-terminated polydimethylsiloxane with γ-cyclodextrin and then modifying with acid anhydride.

[0008] In the present invention, vinyl-terminated polydimethylsiloxane and γ-cyclodextrin are self-assembled, and the cyclic component γ-cyclodextrin is threaded onto the main chain of vinyl-terminated polydimethylsiloxane, thereby forming a sliding ring on the modified polyrotaxane molecular chain. Then, through anhydride modification, the anhydride reacts with the hydroxyl groups on γ-cyclodextrin to carry out an esterification reaction, introducing double bonds into γ-cyclodextrin to obtain a modified polyrotaxane. Using the modified polyrotaxane as the matrix material and silicone oil as the fluid material, vinyl-terminated polydimethylsiloxane reacts with a crosslinking agent to form a network structure. γ-cyclodextrin is threaded onto the main chain of the network structure. The silicone oil reacts with the double bonds on γ-cyclodextrin, causing the silicone oil to be grafted onto γ-cyclodextrin. The middle part of the silicone oil is constrained on the sliding ring, and its two ends are free, forming a freely sliding suspension chain with two free ends, that is, the suspension chain is grafted onto the sliding ring. The sliding of the suspension chain following the sliding ring brings friction, forming a damping material with excellent damping performance and mechanical properties. The precipitation and migration of the silicone oil are prevented by the chemical bond between the silicone oil and γ-cyclodextrin. Moreover, due to the freedom and slidability of the two ends of the silicone oil molecular chain, on the one hand, it can endow the material with sufficient viscous flow characteristics to broaden the temperature range and solve the problem that the fixed ends of the suspension chain affect the viscous flow characteristics; on the other hand, it can enhance the sliding friction and increase the loss factor, solving the problem that the insufficient slippage and small friction of the suspension chain caused by the fixed ends of the suspension chain, thereby significantly improving the damping peak value of the damping material and enhancing the damping effect.

[0009] Further, the molar ratio of the vinyl group of the vinyl-terminated polydimethylsiloxane, the hydroxyl group of the γ-cyclodextrin, and the anhydride group of the anhydride is 1:4 - 6:35 - 45.

[0010] Further, the preparation method of the modified polyrotaxane includes the following steps: a. Disperse vinyl-terminated polydimethylsiloxane in a saturated aqueous solution of γ-cyclodextrin, stir ultrasonically for 10 - 20 min, and stand at room temperature for 10 - 12 h to precipitate a quasi-polyrotaxane; b. Dissolve the quasi-polyrotaxane and the anhydride in a solvent, react at a constant temperature of 75 - 90 °C for 8 - 12 h, and precipitate with chloroform at room temperature to obtain the modified polyrotaxane.

[0011] React vinyl-terminated polydimethylsiloxane with a saturated aqueous solution of γ-cyclodextrin so that γ-cyclodextrin is threaded onto the molecular chain of the vinyl-terminated polydimethylsiloxane axis to form a sliding ring. The obtained product is washed and other steps to obtain a quasi-polyrotaxane with better purity, and it is modified and grafted with an anhydride. On the one hand, a polyrotaxane with a higher molecular weight and a longer molecular chain can be obtained, and on the other hand, double bonds can be introduced into γ-cyclodextrin to facilitate subsequent grafting with silicone oil. The synthesis process of the modified polyrotaxane refers to Figure 1 .

[0012] Preferably, the precipitate product in step a is washed with tetrahydrofuran and water, and vacuum dried at 70-80 °C to obtain a quasi-polyrotaxane. The precipitated product in step b is washed with acetone and vacuum dried at 80-85 °C to obtain the modified polyrotaxane.

[0013] Furthermore, the anhydride is maleic anhydride.

[0014] Furthermore, the mass ratio of the solvent to the anhydride is 10-30:1, the solvent is N,N-dimethylformamide, and the mass ratio of chloroform to the anhydride is 20-40:1. The above solvents can dissolve both maleic anhydride and the modified polyrotaxane, which helps the reaction proceed.

[0015] Furthermore, the crosslinking agent is hydrogen-containing silicone oil, and the hydrogen content of the hydrogen-containing silicone oil is 0.18%-1.6%. Selecting hydrogen-containing silicone oil as the crosslinking agent is beneficial to the crosslinking reaction between the hydrogen-containing silicone oil and the vinyl groups in the modified polyrotaxane. Utilizing the reaction between the silicon-hydrogen bond and the carbon-carbon double bond, and optimizing the hydrogen content of the hydrogen-containing silicone oil can improve the crosslinking degree and form a uniform crosslinked network. At the same time, it is beneficial to form a damping material with a higher molecular weight and longer molecular chains, increasing the diversity of its motion units and broadening its damping relaxation spectrum, so that the damping material exhibits excellent damping temperature range.

[0016] Furthermore, the viscosity of the silicone oil is 6 million - 10 million cs, and the molecular weight is 5000 - 300000.

[0017] Furthermore, the silicone oil is dimethyl silicone oil, diethyl silicone oil or methylphenyl silicone oil. Optimizing the selection of the components of the silicone oil, as well as its viscosity and molecular weight, is beneficial to obtaining a damping material with better comprehensive quality.

[0018] A preparation method of a sliding ring damping material containing free hanging chains includes the following steps: mixing silicone oil, modified polyrotaxane and a crosslinking agent, curing at 25-150 °C for 10 min - 5 h, and then irradiating and crosslinking under γ-rays for 1-4 d.

[0019] During the curing process, vinyl-terminated polydimethylsiloxane reacts with the crosslinking agent to form a network structure, and γ-cyclodextrin threads through the main chain of the network structure. After irradiation under γ-rays, the methyl groups of the silicone oil form free radicals and quickly react with the double bonds on γ-cyclodextrin, causing the silicone oil to graft onto γ-cyclodextrin. The middle part of the silicone oil is constrained on the sliding ring, and its two ends are free, forming a freely sliding hanging chain at both ends, that is, grafting the hanging chain onto the sliding ring. The sliding of the hanging chain following the sliding ring brings friction, forming a damping material with excellent damping performance and mechanical properties. The structure after irradiation crosslinking refers to Figure 2 .

[0020] Furthermore, the irradiation dose is 10-100 kgy, and the dose rate is 5-20 gy / min. Gamma rays are selected and the irradiation dose of the rays is strictly controlled to facilitate the grafting of the suspension chain on the sliding ring. If the irradiation dose is too low, effective grafting cannot be formed. If the irradiation dose is too high, the damping material obtained will become hard, which significantly affects the damping performance of the damping material.

[0021] The technical solution of the present invention has at least the following advantages and beneficial effects:

[0022] Modified polyrotaxane is used as the matrix material, silicone oil is used as the fluid material, vinyl-terminated polydimethylsiloxane reacts with a crosslinker to form a network structure, and γ-cyclodextrin is threaded on the main chain of the network structure. After irradiation with γ rays, the methyl groups of the silicone oil form free radicals and quickly react with the double bonds on γ-cyclodextrin, so that the silicone oil is grafted on γ-cyclodextrin, and the middle part of the silicone oil is constrained on the sliding ring, and its two ends are free, forming a slidable suspension chain with free ends, that is, the suspension chain is grafted on the sliding ring, and the suspension chain slides with the sliding ring to bring friction, forming a damping material with excellent damping performance and mechanical properties. The chemical bond between silicone oil and γ-cyclodextrin prevents the precipitation and migration of silicone oil. In addition, due to the freedom and slidability of the two ends of the silicone oil molecular chain, the material has sufficient viscosity and flow characteristics to widen the temperature range, and can also enhance sliding friction and increase the loss factor, improve the damping peak of the damping material, and enhance the damping effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the synthesis of the modified polyrotaxane of the present invention;

[0024] Figure 2 Schematic diagram of the structure of the damping material of the present invention, wherein PS is vinyl-terminated polydimethylsiloxane;

[0025] Figure 3 It is a damping performance diagram of the embodiment of the present invention and the comparative example;

[0026] Figure 4 It is a mechanical property diagram of the embodiment of the present invention and the comparative example. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0028] Example 1

[0029] A sliding ring damping material containing free-hanging chains, comprising the following raw materials in parts by weight: 10 parts of methylphenyl silicone oil, 90 parts of modified polyrotaxane, and 2 parts of crosslinking agent; the viscosity of the methylphenyl silicone oil is 6 million cs, and the molecular weight is 5000; the crosslinking agent is hydrogen-containing silicone oil, and the hydrogen content of the hydrogen-containing silicone oil is 0.36%.

[0030] A preparation method of a sliding ring damping material containing free-hanging chains, comprising the following steps:

[0031] Preparation of modified polyrotaxane: a. Mix vinyl-terminated polydimethylsiloxane with a saturated aqueous solution of γ-cyclodextrin, stir ultrasonically for 12 min, stand at room temperature for 10 h, centrifuge to collect the precipitate, wash with tetrahydrofuran and water, and then dry in vacuum at 70 °C to obtain quasi-polyrotaxane; b. Dissolve the quasi-polyrotaxane and maleic anhydride in 30 mL of N,N-dimethylformamide, react at a constant temperature of 75 °C for 12 h, precipitate the product with 30 mL of chloroform, and wash the product thoroughly with acetone, and dry in vacuum at 80 °C to obtain modified polyrotaxane; wherein, the molar ratio of the vinyl group of vinyl-terminated polydimethylsiloxane, the hydroxyl group of γ-cyclodextrin, and the anhydride group of maleic anhydride is 1:4:35.

[0032] Preparation of the damping material: Mix methylphenyl silicone oil, modified polyrotaxane, and hydrogen-containing silicone oil and stir for 20 min, cure at 100 °C for 2 h, and then carry out a crosslinking reaction for 2 d under irradiation conditions of γ-rays, an irradiation dose of 10 kGy, and a dose rate of 20 Gy / min.

[0033] Example 2

[0034] A sliding ring damping material containing free-hanging chains, comprising the following raw materials in parts by weight: 50 parts of methylphenyl silicone oil, 50 parts of modified polyrotaxane, and 5 parts of crosslinking agent; the viscosity of the methylphenyl silicone oil is 10 million cs, and the molecular weight is 300000; the crosslinking agent is hydrogen-containing silicone oil, and the hydrogen content of the hydrogen-containing silicone oil is 1.6%.

[0035] A preparation method of a sliding ring damping material containing free-hanging chains, comprising the following steps:

[0036] Preparation of modified polyrotaxane: a. Mix vinyl-terminated polydimethylsiloxane with a saturated aqueous solution of γ-cyclodextrin, stir ultrasonically for 20 min, let stand at room temperature for 12 h, centrifuge to collect the precipitate product, wash with tetrahydrofuran and water, and then dry in vacuo at 80 °C to obtain quasi-polyrotaxane; b. Dissolve the quasi-polyrotaxane and maleic anhydride in 35 mL of N,N-dimethylformamide, react at a constant temperature of 90 °C for 8 h, precipitate the product with 35 mL of chloroform, and wash the product thoroughly with acetone, then dry in vacuo at 85 °C to obtain the modified polyrotaxane; wherein, the molar ratio of the vinyl group of vinyl-terminated polydimethylsiloxane, the hydroxyl group of γ-cyclodextrin, and the anhydride group of maleic anhydride is 1:5:40.

[0037] Preparation of damping material: Mix methylphenyl silicone oil, modified polyrotaxane and hydrogen-containing silicone oil and stir for 35 min, cure at 150 °C for 10 min, and then carry out a cross-linking reaction for 1 d under the irradiation conditions of γ-ray, irradiation dose of 100 kgy, and dose rate of 10 gy / min.

[0038] Example 3

[0039] A sliding ring damping material containing free hanging chains, comprising the following raw materials in parts by weight: 60 parts of silicone oil, 40 parts of modified polyrotaxane and 4 parts of cross-linking agent; the silicone oil is dimethyl silicone oil, the viscosity of the dimethyl silicone oil is 10 million cs, and the molecular weight is 20,000; the cross-linking agent is hydrogen-containing silicone oil, and the hydrogen content of the hydrogen-containing silicone oil is 1%.

[0040] Preparation of damping material: Mix dimethyl silicone oil, modified polyrotaxane and hydrogen-containing silicone oil and stir for 20 min, cure at 25 °C for 5 h, and then carry out a cross-linking reaction for 3 d under the irradiation conditions of γ-ray, irradiation dose of 40 kgy, and dose rate of 20 gy / min.

[0041] The preparation of the modified polyrotaxane is the same as that in Example 1.

[0042] Example 4

[0043] In this example, the silicone oil is diethyl silicone oil, the viscosity of the diethyl silicone oil is 8 million cs, and the molecular weight is 80,000; the rest are the same as in Example 1.

[0044] Example 5

[0045] In this embodiment, the preparation of the modified polyrotaxane is as follows: a. Mix a vinyl-terminated polydimethylsiloxane with a saturated aqueous solution of γ-cyclodextrin, stir ultrasonically for 10 min, let stand at room temperature for 11 h, centrifuge to collect the precipitate, wash with tetrahydrofuran and water, and then dry in vacuum at 75 °C to obtain a quasi-polyrotaxane; b. Dissolve the quasi-polyrotaxane and maleic anhydride in 25 mL of N,N-dimethylformamide, react at a constant temperature of 85 °C for 10 h, precipitate the product with 45 mL of chloroform, and wash the product thoroughly with acetone, then dry in vacuum at 82 °C to obtain the modified polyrotaxane; wherein, the molar ratio of the vinyl group of the vinyl-terminated polydimethylsiloxane, the hydroxyl group of γ-cyclodextrin, and the anhydride group of phthalic anhydride is 1:6:45. The rest are the same as in Example 1.

[0046] Example 6

[0047] In this embodiment, there are 70 parts of methylphenyl silicone oil, 30 parts of modified polyrotaxane, and 0.3 part of crosslinking agent. The rest are the same as in Example 1.

[0048] Example 7

[0049] In this embodiment, there are 80 parts of methylphenyl silicone oil, 20 parts of modified polyrotaxane, and 0.2 part of crosslinking agent. The rest are the same as in Example 1.

[0050] Comparative Example 1

[0051] The difference from Example 7 is that the damping material is a modified polyrotaxane and a crosslinking agent, without dimethyl silicone oil. The rest are the same as in Example 7.

[0052] Comparative Example 2

[0053] The difference from Example 7 is that the damping material is obtained by mixing and stirring dimethyl silicone oil, modified polyrotaxane, and crosslinking agent for 30 min and curing at 100 °C for 40 min. The rest are the same as in Example 7.

[0054] Comparative Example 3

[0055] The difference from Example 7 is that the modified polyrotaxane is replaced with a common polyrotaxane, which is prepared by the following steps: Mix a vinyl-terminated polydimethylsiloxane with a saturated aqueous solution of γ-cyclodextrin, stir ultrasonically for 12 min, let stand at room temperature for 10 h, centrifuge to collect the precipitate, wash with tetrahydrofuran and water, and then dry in vacuum at 70 °C until free of moisture. Among them, the molar ratio of the vinyl group of the vinyl-terminated polydimethylsiloxane to the hydroxyl group of γ-cyclodextrin is 1:4. The rest are the same as in Example 7.

[0056] Comparative Example 4

[0057] The difference from Example 7 is that the irradiation conditions are as follows: the cross-linking reaction is carried out for 10 h under the irradiation conditions of γ-ray and an irradiation dose of 5 kGy; the rest are the same as in Example 7.

[0058] Comparative Example 5

[0059] The difference from Example 7 is that the irradiation conditions are as follows: the cross-linking reaction is carried out for 2 d under the irradiation conditions of γ-ray and an irradiation dose of 150 kGy; the rest are the same as in Example 7.

[0060] Comparative Example 6

[0061] The difference from Example 7 is that the anhydride is phthalic anhydride, and the molar ratio of the vinyl group of the vinyl-terminated polydimethylsiloxane, the hydroxyl group of γ-cyclodextrin, and the anhydride group of phthalic anhydride is 1:5:40; the rest are the same as in Example 7.

[0062] Performance detection test

[0063] The damping materials prepared in Examples 1-7 and Comparative Examples 1-6 were subjected to damping tests: the test temperature range was from -55 °C to 200 °C, the heating rate was 3 °C / min, the frequency was selected as 1 Hz, and the oscillation strain was set to 0.5%. The damping temperature ranges of the damping materials in each example were recorded respectively when Tanδ>0.5, Tanδ>0.7, and Tanδ>1.0. At the same time, the peak value of the damping factor and the temperature corresponding to the peak value were recorded. The results are shown in Table 1. Among them, the damping curves of Example 1, Example 2, Example 6, Example 7, Comparative Example 1, and Comparative Example 3 are as Figure 3 shown.

[0064] The damping material samples obtained in Examples 1-7 and Comparative Examples 1-6 were subjected to mechanical property tests according to GB / T528-2009 "Test Method for Rubber Tensile Properties", and their elongation at break was recorded. The results are shown in Table 1. Among them, the mechanical properties of Example 1, Example 2, and Comparative Examples 1-3 are as Figure 4 shown.

[0065] Table 1

[0066]

[0067] Table 2

[0068] Breaking elongation rate / % Example 1 600 Example 2 603 Example 3 620 Example 4 600 Example 5 625 Example 6 610 Example 7 650 Comparative Example 1 165 Comparative Example 2 175 Comparative Example 3 350 Comparative Example 4 460 Comparative Example 5 440 Comparative Example 6 580

[0069] Combined with Examples 1-7 and Table 1 and Table 2, it can be seen that by using the raw material components of the present invention and combining with specific process conditions, the damping material has excellent damping effects and mechanical properties, can effectively improve the loss factor of the damping material, improve the damping peak value of the damping material, and has a wide damping temperature range. The elongation at break of the damping material is as high as more than 600%.

[0070] Combined with Example 7, Comparative Example 1 and Comparative Example 3 and Figure 3 It can be seen that in Comparative Example 1, there is no silicone oil fluid and there is basically no damping performance. In Comparative Example 3, a common quasi-polyrotaxane is used and effective grafting cannot be formed, resulting in a significant decrease in the damping performance of the obtained damping material, a poor peak value of the loss factor, and the inability to achieve a high damping effect.

[0071] Combined with Example 7, Comparative Examples 1-4 and Figure 4 It can be seen that in terms of mechanical properties, in Comparative Example 1, there is no silicone oil fluid, and in Comparative Example 2, no specific irradiation is carried out. The elongation at break of the damping materials obtained in Comparative Example 1 and Comparative Example 2 is not much different, but both are significantly lower than that of Example 7. The mechanical properties of the damping materials obtained in Comparative Examples 3-5 are significantly worse. Thus, it can be seen that the raw material components and process conditions in the present invention complement each other and cooperate with each other to obtain a damping material with high damping, wide temperature range and excellent elongation at break.

[0072] Combined with Example 7, Comparative Example 6 and Table 1, it can be seen that in Comparative Example 6, the acid anhydride is phthalic anhydride, and the damping performance of the obtained damping material is significantly decreased, the peak value of the loss factor is poor, and the high damping effect cannot be achieved. After phthalic anhydride modifies the polyrotaxane, during the radiation crosslinking process, phthalic anhydride cannot introduce double bonds into γ-cyclodextrin, and silicone oil cannot be grafted to γ-cyclodextrin, thus a sliding ring containing free hanging chains cannot be formed, affecting the damping performance of the damping material.

[0073] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, various changes and modifications can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A sliding ring damping material containing a free hanging chain, characterized in that: The damping material comprises, by weight, 10-80 parts of silicone oil, 20-90 parts of modified polyrotaxane and 0.2-9 parts of a crosslinking agent. The modified polyrotaxane is prepared by reacting vinyl-terminated polydimethylsiloxane with gamma-cyclodextrin and then modifying it with anhydride.

2. The sliding ring damping material with free hanging chain according to claim 1, characterized in that: The molar ratio of the vinyl group of the vinyl-terminated polydimethylsiloxane, the hydroxyl group of the γ-cyclodextrin and the anhydride group of the acid anhydride is 1:4-6:35-45.

3. The sliding ring damping material with free hanging chain according to claim 2, characterized in that: The preparation method of the modified polyrotaxane comprises the following steps: a. dispersing vinyl-terminated polydimethylsiloxane in a saturated aqueous solution of γ-cyclodextrin, stirring with ultrasound for 10-20 minutes, standing at room temperature for 10-12 hours, and precipitating to obtain a pseudo-polyrotaxane; b. dissolving the pseudo-polyrotaxane and anhydride in a solvent, reacting at a constant temperature of 75-90° C. for 8-12 hours, and precipitating with chloroform at room temperature to obtain the modified polyrotaxane.

4. The sliding ring damping material with free hanging chain according to claim 3, characterized in that: The acid anhydride is maleic anhydride.

5. The sliding ring damping material with free hanging chain according to claim 4, characterized in that: The mass ratio of the solvent to the acid anhydride is 10-30:1, the solvent is N,N-dimethylformamide, and the mass ratio of the chloroform to the acid anhydride is 20-40:

1.

6. The sliding ring damping material with free hanging chain according to claim 1, characterized in that: The cross-linking agent is hydrogen-containing silicone oil, and the hydrogen content of the hydrogen-containing silicone oil is 0.18%-1.6%.

7. The sliding ring damping material with free hanging chain according to claim 1, characterized in that: The silicone oil has a viscosity of 6-10 million cs and a molecular weight of 5,000-300,000.

8. The sliding ring damping material with free hanging chain according to claim 7, characterized in that: The silicone oil is dimethyl silicone oil, diethyl silicone oil or methylphenyl silicone oil.

9. The method for preparing a sliding ring damping material containing a free hanging chain according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: mixing silicone oil, modified polyrotaxane and a crosslinking agent, curing at 25-150° C. for 10 min-5 h, and then irradiating and crosslinking under gamma rays for 1-4 d.

10. The method for preparing a sliding ring damping material containing a free hanging chain according to claim 9, characterized in that: The irradiation dose is 10-100 kgy and the dose rate is 5-20 gy / min.

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