Low-temperature-resistant organic silicon elastic damping body and preparation method thereof

Abstract

The invention discloses a low-temperature-resistant organic silicon elastic damping body and a preparation method thereof, and belongs to the field of synthesis of organic polymer materials. The invention relates to a high-efficiency photoinitiator, which is prepared from the following ingredients in parts by weight: 95 to 110 parts of fluorosiloxane-phenylsiloxane segmented copolymers, 25 to 35 parts of boric acid ester end-capped polyurethane prepolymers, 10 to 15 parts of neodymium-containing metal organic frameworks, 20 to 40 parts of azobenzene modified CNT / TiO2, 2 to 4 parts of photoinitiators 1173 and 2 to 3 parts of neodymium acetylacetonate. Ultralow-temperature adaptability, self-repairing and high-modulus coexistence and wide-temperature-range damping stability are achieved through fluorosilicone / phenyl block copolymer molecular design, a borate-neodymium coordination double-dynamic network, stress response filler and a light-heat gradient curing process. The low-temperature-resistant organic silicon elastic damping body prepared by the invention provides a new solution idea for an extreme environment damping material, and has a wide application prospect.

Description

Technical Field

[0001] The invention belongs to the field of organic polymer material synthesis, and particularly relates to a low-temperature resistant organic silicon elastic damping body and a preparation method thereof. Background Art

[0002] Silicone elastomers are ideal for low-temperature damping materials due to their unique molecular structure. Their backbone consists of silicon-oxygen bonds, which have a bond energy far higher than that of C-C bonds, giving the material excellent thermal stability and flexibility. Pendant groups are organic groups such as methyl and phenyl, and the glass transition temperature (Tg) of the material can be controlled by adjusting the type and proportion of these pendant groups. In low-temperature environments, traditional rubber materials harden and lose their elasticity due to glass transition, but silicone elastomers maintain exceptional flexibility, with a Tg as low as -70°C to -140°C. This characteristic makes them irreplaceable in aerospace, polar equipment, cryogenic engineering, and other fields.

[0003] Patent application publication number CN118909452A discloses a polyurethane-modified organosilicon damping material for the leading edge of wind turbine blades. It uses acrylate-hindered phenol-modified methylphenyl silicone oil as the main agent and vinyl polyurethane as a modifier, enhancing damping performance through hydrogen bonding. However, its formulation contains fillers such as mica flakes and white carbon black, resulting in a complex dispersion process and requiring peroxide curing, posing a risk of thermal runaway. Patent application publication number CN109021196A discloses an organosilicon-based polyurethane damping material and its preparation method. This material synthesizes a prepolymer from a homocarbon / homosilicon dimethyl diol and a diisocyanate, introducing flexible segments to enhance low-temperature toughness. The organosilicon segments improve heat resistance and hydrolysis resistance, making it suitable for use in extreme environments such as aerospace and navigation. However, its chain extender requires custom synthesis, resulting in high raw material costs. Specific low-temperature damping values ​​are not disclosed, and performance verification is insufficient.

[0004] In order to improve the damping performance of silicone rubber, damping additives with polar groups or large rigid groups (such as triphenyl groups and imide groups) on the side groups are usually added to the formula. The synergistic effect and large steric hindrance between the polar side groups and the phenyl groups in the silicone rubber are used to increase the friction between the molecular chains, increase the loss modulus, and thus improve the damping factor. However, the addition of such damping agents to silicone rubber often increases the glass transition temperature of silicone rubber, reducing the advantage of silicone rubber's modulus stability in a wide temperature range (-50-200°C), thereby limiting its application in certain fields such as weapon equipment.

[0005] Therefore, a low-temperature resistant organic silicon elastic damping body and a preparation method thereof are proposed to solve the above problems. Summary of the Invention

[0006] The object of the present invention is to provide a low-temperature resistant organic silicon elastic damper and a preparation method thereof, so as to improve the low-temperature resistance and mechanical properties of the organic silicon elastic damper and at the same time have a higher damping loss factor.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A low-temperature resistant organosilicon elastic damper comprises, by weight, 95-110 parts of a fluorosilicone-phenylsiloxane block copolymer, 25-35 parts of a borate-terminated polyurethane prepolymer, 10-15 parts of Nd@MOF-808 (a neodymium-containing metal organic framework), 20-40 parts of azobenzene-modified CNT / TiO2, 2-4 parts of a photoinitiator 1173, and 2-3 parts of neodymium acetylacetonate.

[0009] Furthermore, the fluorosilicone-phenylsilicone block copolymer is prepared by the following steps:

[0010] Under nitrogen protection, trifluoropropylmethylcyclotrisiloxane and tetramethylammonium hydroxide are uniformly mixed, heated to 85-90°C and reacted for 3-4 hours to obtain dihydroxy polytrifluoropropylmethylsiloxane; then methylphenylcyclotrisiloxane is added, the temperature is raised to 115-120°C and the reaction is continued for 5-6 hours; finally, the temperature is raised to 155-160°C and the mixture is removed under reduced pressure to obtain a fluorosilicone-phenylsiloxane block copolymer.

[0011] Furthermore, the weight ratio of the trifluoropropylmethylcyclotrisiloxane, tetramethylammonium hydroxide and methylphenylcyclotrisiloxane is (45-55): (0.03-0.06): (30-35).

[0012] Furthermore, the borate-terminated polyurethane prepolymer is prepared by the following steps:

[0013] PTMG2000 and IPDI were mixed and reacted at 75-80°C for 3-4 hours. 4-Hydroxymethylphenylboric acid and dibutyltin dilaurate were then added and reacted at 65-70°C for 8-9 hours. The product was dissolved in tetrahydrofuran, precipitated in deionized water, and vacuum dried to obtain a borate-terminated polyurethane prepolymer.

[0014] Furthermore, the weight ratio of the PTMG2000, IPDI, 4-hydroxymethylphenylboric acid and dibutyltin dilaurate is (95-110): (20-25): (6-9): (0.04-0.07).

[0015] Furthermore, the azobenzene-modified CNT / TiO2 is prepared by the following steps:

[0016] CNTs are treated with mixed acid oxidation to obtain carboxylated CNTs; TiO2 is deposited on the surface of the carboxylated CNTs using TiCl4 and H2O as precursors at a temperature of 145-150°C, and the cycle is repeated 200-210 times to obtain TiO2@CNTs; HPAAB is reacted with SOCl2 to obtain HPAAB chloride; TiO2@CNTs and HPAAB chloride are refluxed in toluene for 12-14 hours to obtain azobenzene-modified CNT / TiO2.

[0017] Furthermore, the mixed acid is a mixture of H2SO4 and HNO3 in a volume ratio of 3:1.

[0018] Furthermore, the TiO2 deposition thickness in the TiO2@CNT is 4-8 nm.

[0019] A method for preparing a low-temperature resistant organic silicon elastic damper comprises the following steps:

[0020] S1. Mix fluorosilicone-phenylsiloxane block copolymer and borate-terminated polyurethane; add Nd@MOF-808 and azobenzene-modified CNT / TiO2 in batches, control the temperature and mix; stir and degas under vacuum; after cooling, add photoinitiator 1173 and neodymium acetylacetonate, stir in the dark, and obtain a mixed slurry;

[0021] S2. Inject the mixed slurry into the mold and irradiate it under a UV light source with a wavelength of 300-400nm for 5-10 minutes; heat it to 55-60℃ and cure it for 2-2.5h, continue to heat it to 75-80℃ and cure it for 1.5-2h, and finally heat it to 105-110℃ and cure it for 4-4.5h to obtain a low-temperature resistant silicone elastic damping body.

[0022] At 60-80℃, Nd acetylacetonate catalyzes 3+ The coordination reaction with the carboxyl group completes the condensation reaction of the borate ester bond and the silanol group at 110°C.

[0023] Furthermore, the temperature of the temperature-controlled mixing is 40-45°C; the temperature of the cooling is 30-35°C.

[0024] Furthermore, the stirring and degassing time is 25-40 minutes; the light-shielding stirring time is 10-15 minutes.

[0025] Beneficial effects of the present invention:

[0026] (1) The trifluoropropyl segment in the fluorosilicone-phenylsiloxane block copolymer used in the present invention provides an ultra-low rotation barrier, giving the molecular chain the ability to move at extremely low temperatures; the phenylsiloxane segment enhances the intermolecular force, maintains the cohesive strength of the material, and avoids the attenuation of the mechanical properties of pure fluorosilicone rubber. The two work together to achieve a balance between low-temperature flexibility and damping performance, significantly broadening the applicable temperature range of the material. The borate bond in the borate-terminated polyurethane prepolymer used has temperature-responsive dynamic characteristics: it remains stable below -60°C; when the temperature rises above -40°C, the bond energy decreases and reversible dissociation occurs. This design allows the material to dissipate energy through bond breakage under low-temperature impact and self-repair under static conditions.

[0027] (2) The core-shell dynamic cross-linked network design adopted by the present invention: borate-terminated polyurethane is used as the shell, and its dynamic borate bonds undergo reversible fracture / reorganization under low-temperature impact, efficiently dissipating mechanical energy and imparting self-repairing properties; fluorosilicone-phenylsiloxane is used as the core, which provides a basic platform for chain segment movement and ensures ultra-low temperature elasticity; and neodymium metal organic framework (Nd@MOF-808) is used as a coordination cross-linking point, forming high-bond energy complex bonds with polysiloxane carboxyl groups to enhance network stability. The three work together to construct a composite network, achieving high damping and creep resistance simultaneously over a wide temperature range.

[0028] (3) The use of azobenzene-modified CNT / TiO2 filler can not only enhance the filler-matrix interface bonding strength and avoid stress concentration; its surface azobenzene groups undergo reversible cis-trans isomerization under mechanical stress, providing additional energy dissipation channels, achieving damping improvement without affecting the low-temperature flexibility of the material under static conditions. DETAILED DESCRIPTION

[0029] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0030] Example 1

[0031] This embodiment provides a low-temperature-resistant organic silicon elastic damper, which is prepared by the following steps:

[0032] S1. Under dry nitrogen protection, 50 parts of trifluoropropylmethylcyclotrisiloxane and 0.05 parts of tetramethylammonium hydroxide were added to a reactor, and the temperature was raised to 90°C for reaction for 3 hours to obtain dihydroxy polytrifluoropropylmethylsiloxane; 33.3 parts of methylphenylcyclotrisiloxane were added, and the temperature was raised to 120°C and the reaction was continued for 5 hours; finally, the temperature was raised to 160°C and the reaction was removed under reduced pressure to obtain a fluorosilicone-phenylsiloxane block copolymer;

[0033] 100 parts of PTMG2000 (polytetramethylene ether glycol) and 22.2 parts of IPDI (isophorone diisocyanate) were reacted at 80°C for 3 hours, and then 7.6 parts of 4-hydroxymethylphenylboric acid and 0.05 parts of dibutyltin dilaurate were added and reacted at 70°C for 8 hours. The product was dissolved in tetrahydrofuran, precipitated in deionized water, and vacuum dried to obtain a borate-terminated polyurethane prepolymer;

[0034] CNTs (carbon nanotubes) were oxidized with a mixed acid (H2SO4:HNO3=3:1) to obtain carboxylated CNTs. TiO2 was deposited on the CNT surface at 150°C using TiCl4 and H2O as precursors for 200 cycles to obtain TiO2@CNT (TiO2 deposition thickness 5 nm). HPAAB (4-(4-hydroxyphenylazo)benzoic acid) was reacted with SOCl2 to obtain HPAAB chloride. TiO2@CNT and HPAAB chloride were refluxed in toluene for 12 hours to obtain azobenzene-modified CNT / TiO2.

[0035] S2. Add 100 parts of fluorosilicone-phenylsiloxane block copolymer and 25 parts of borate-terminated polyurethane into a planetary mixer and mix them evenly; add 12 parts of Nd@MOF-808 and 30 parts of azobenzene-modified CNT / TiO2 in three times, control the temperature to 40°C and mix evenly; stir and deaerate at -0.095 MPa vacuum for 30 minutes until no bubbles are visible; after cooling to 30°C, add 3 parts of photoinitiator 1173 and 1.5 parts of neodymium acetylacetonate, stir in the dark for 10 minutes to obtain a mixed slurry;

[0036] S3, the mixed slurry was injected into the mold and placed under a UV light source with a wavelength of 365nm (intensity of 80mW / cm 2 ) irradiated for 5 minutes; heated to 60 ° C and cured for 2 hours, continued to heat up to 80 ° C and cured for 2 hours, and finally heated to 110 ° C and cured for 4 hours to obtain a low-temperature resistant silicone elastic damping body.

[0037] Example 2

[0038] Compared with Example 1, this embodiment differs in that the amount of the fluorosilicone-phenylsilicone block copolymer is increased. The specific implementation steps of S2 are:

[0039] S2. Add 108 parts of fluorosilicone-phenylsiloxane block copolymer and 22 parts of borate-terminated polyurethane into a planetary mixer and mix them evenly; add 11 parts of Nd@MOF-808 and 30 parts of azobenzene-modified CNT / TiO2 in three times, control the temperature to 40°C and mix evenly; stir and degas under a vacuum degree of -0.095 MPa for 30 minutes until no bubbles are visible; after cooling to 30°C, add 3 parts of photoinitiator 1173 and 1.5 parts of neodymium acetylacetonate, stir in the dark for 10 minutes to obtain a mixed slurry;

[0040] The remaining raw materials and preparation process remain the same as in Example 1.

[0041] Example 3

[0042] Compared with Example 1, this embodiment differs in that the amount of the fluorosilicone-phenylsilicone block copolymer is reduced. The specific implementation steps of S2 are:

[0043] S2. Add 95 parts of fluorosilicone-phenylsiloxane block copolymer and 30 parts of borate-terminated polyurethane into a planetary mixer and mix them evenly; add 12 parts of Nd@MOF-808 and 30 parts of azobenzene-modified CNT / TiO2 in three times, control the temperature to 40°C and mix evenly; stir and degas under a vacuum of -0.095 MPa for 30 minutes until no bubbles are visible; after cooling to 30°C, add 3 parts of photoinitiator 1173 and 1.5 parts of neodymium acetylacetonate, stir in the dark for 10 minutes to obtain a mixed slurry;

[0044] The remaining raw materials and preparation process remain the same as in Example 1.

[0045] Example 4

[0046] Compared with Example 1, this embodiment differs in that the amount of azobenzene-modified CNT / TiO2 filler is increased. The specific implementation steps of S2 are:

[0047] S2. Add 100 parts of fluorosilicone-phenylsiloxane block copolymer and 25 parts of borate-terminated polyurethane into a planetary mixer and mix them evenly; add 10 parts of Nd@MOF-808 and 40 parts of azobenzene-modified CNT / TiO2 in three times, control the temperature to 40°C and mix evenly; stir and deaerate at a vacuum degree of -0.095 MPa for 30 minutes until no bubbles are visible; after cooling to 30°C, add 3 parts of photoinitiator 1173 and 1.5 parts of neodymium acetylacetonate, stir in the dark for 10 minutes to obtain a mixed slurry;

[0048] The remaining raw materials and preparation process remain the same as in Example 1.

[0049] Example 5

[0050] Compared with Example 1, this embodiment differs in that the amount of azobenzene-modified CNT / TiO2 filler is reduced. The specific implementation steps of S2 are:

[0051] S2. Add 100 parts of fluorosilicone-phenylsiloxane block copolymer and 25 parts of borate-terminated polyurethane into a planetary mixer and mix them evenly; add 15 parts of Nd@MOF-808 and 20 parts of azobenzene-modified CNT / TiO2 in three times, control the temperature to 40°C and mix evenly; stir and degas under a vacuum degree of -0.095 MPa for 30 minutes until no bubbles are visible; after cooling to 30°C, add 3 parts of photoinitiator 1173 and 1.5 parts of neodymium acetylacetonate, stir in the dark for 10 minutes to obtain a mixed slurry;

[0052] The remaining raw materials and preparation process remain the same as in Example 1.

[0053] Comparative Example 1

[0054] This comparative example is different from Example 1 in that the fluorosilicone-phenylsiloxane block copolymer is not modified. The specific implementation steps are as follows:

[0055] S1. 100 parts of PTMG2000 (polytetramethylene ether glycol) and 22.2 parts of IPDI (isophorone diisocyanate) were reacted at 80° C. for 3 hours, and then 7.6 parts of 4-hydroxymethylphenylboric acid and 0.05 parts of dibutyltin dilaurate were added, and the mixture was reacted at 70° C. for 8 hours. The product was dissolved in tetrahydrofuran, precipitated in deionized water, and vacuum dried to obtain a borate-terminated polyurethane prepolymer;

[0056] CNTs (carbon nanotubes) were oxidized with a mixed acid (H2SO4:HNO3=3:1) to obtain carboxylated CNTs. TiO2 was deposited on the CNT surface at 150°C using TiCl4 and H2O as precursors for 200 cycles to obtain TiO2@CNT (TiO2 deposition thickness 5 nm). HPAAB (4-(4-hydroxyphenylazo)benzoic acid) was reacted with SOCl2 to obtain HPAAB chloride. TiO2@CNT and HPAAB chloride were refluxed in toluene for 12 hours to obtain azobenzene-modified CNT / TiO2.

[0057] S2. Add 100 parts of trifluoropropylmethylcyclotrisiloxane and 25 parts of borate-terminated polyurethane into a planetary mixer and mix them evenly; add 12 parts of Nd@MOF-808 and 30 parts of azobenzene-modified CNT / TiO2 in three times, control the temperature to 40°C and mix evenly; stir and degas under a vacuum of -0.095 MPa for 30 minutes until no bubbles are visible; after cooling to 30°C, add 3 parts of photoinitiator 1173 and 1.5 parts of neodymium acetylacetonate, stir in the dark for 10 minutes to obtain a mixed slurry;

[0058] S3, the mixed slurry was injected into the mold and placed under a UV light source with a wavelength of 365nm (intensity of 80mW / cm 2) irradiated for 5 minutes; heated to 60 ° C and cured for 2 hours, continued to heat up to 80 ° C and cured for 2 hours, and finally heated to 110 ° C and cured for 4 hours to obtain a low-temperature resistant silicone elastic damping body.

[0059] The remaining raw materials and preparation process remain the same as in Example 1.

[0060] Comparative Example 2

[0061] This comparative example is different from Example 1 in that the borate-terminated polyurethane prepolymer is not modified. The specific implementation steps are as follows:

[0062] S1. Under dry nitrogen protection, 50 parts of trifluoropropylmethylcyclotrisiloxane and 0.05 parts of tetramethylammonium hydroxide were added to a reactor, and the temperature was raised to 90°C for reaction for 3 hours to obtain dihydroxy polytrifluoropropylmethylsiloxane; 33.3 parts of methylphenylcyclotrisiloxane were added, and the temperature was raised to 120°C and the reaction was continued for 5 hours; finally, the temperature was raised to 160°C and the reaction was removed under reduced pressure to obtain a fluorosilicone-phenylsiloxane block copolymer;

[0063] CNTs (carbon nanotubes) were oxidized with a mixed acid (H2SO4:HNO3=3:1) to obtain carboxylated CNTs. TiO2 was deposited on the CNT surface at 150°C using TiCl4 and H2O as precursors for 200 cycles to obtain TiO2@CNT (TiO2 deposition thickness 5 nm). HPAAB (4-(4-hydroxyphenylazo)benzoic acid) was reacted with SOCl2 to obtain HPAAB chloride. TiO2@CNT and HPAAB chloride were refluxed in toluene for 12 hours to obtain azobenzene-modified CNT / TiO2.

[0064] S2. Add 100 parts of fluorosilicone-phenylsiloxane block copolymer and 25 parts of PTMG2000 into a planetary mixer and mix them evenly; add 12 parts of Nd@MOF-808 and 30 parts of azobenzene-modified CNT / TiO2 in three times, control the temperature to 40°C and mix evenly; stir and deaerate at a vacuum degree of -0.095 MPa for 30 minutes until no bubbles are visible; after cooling to 30°C, add 3 parts of photoinitiator 1173 and 1.5 parts of neodymium acetylacetonate, stir in the dark for 10 minutes to obtain a mixed slurry;

[0065] S3, the mixed slurry was injected into the mold and placed under a UV light source with a wavelength of 365nm (intensity of 80mW / cm 2 ) irradiated for 5 minutes; heated to 60 ° C and cured for 2 hours, continued to heat up to 80 ° C and cured for 2 hours, and finally heated to 110 ° C and cured for 4 hours to obtain a low-temperature resistant silicone elastic damping body.

[0066] The remaining raw materials and preparation process remain the same as in Example 1.

[0067] Comparative Example 3

[0068] This comparative example is different from Example 1 in that neither the fluorosilicone-phenylsiloxane block copolymer nor the borate-terminated polyurethane prepolymer is modified. The specific implementation steps are as follows:

[0069] S1. CNTs (carbon nanotubes) were oxidized with a mixed acid (H2SO4:HNO3=3:1) to obtain carboxylated CNTs. TiO2 was deposited on the CNT surface at 150°C using TiCl4 and H2O as precursors for 200 cycles to obtain TiO2@CNT (TiO2 deposition thickness 5 nm). 5 parts of HPAAB (4-(4-hydroxyphenylazo)benzoic acid) were reacted with SOCl2 to obtain HPAAB chloride. TiO2@CNT and HPAAB chloride were refluxed in toluene for 12 hours to obtain azobenzene-modified CNT / TiO2.

[0070] S2. Add 100 parts of trifluoropropylmethylcyclotrisiloxane and 25 parts of PTMG2000 into a planetary mixer and mix them evenly; add 12 parts of Nd@MOF-808 and 30 parts of azobenzene-modified CNT / TiO2 in three times, control the temperature to 40°C and mix evenly; stir and deaerate at a vacuum degree of -0.095 MPa for 30 minutes until no bubbles are visible; after cooling to 30°C, add 3 parts of photoinitiator 1173 and 1.5 parts of neodymium acetylacetonate, stir in the dark for 10 minutes to obtain a mixed slurry;

[0071] S3, the mixed slurry was injected into the mold and placed under a UV light source with a wavelength of 365nm (intensity of 80mW / cm 2 ) irradiated for 5 minutes; heated to 60 ° C and cured for 2 hours, continued to heat up to 80 ° C and cured for 2 hours, and finally heated to 110 ° C and cured for 4 hours to obtain a low-temperature resistant silicone elastic damping body.

[0072] The remaining raw materials and preparation process remain the same as in Example 1.

[0073] Comparative Example 4

[0074] This comparative example differs from Example 1 in that CNT / TiO2 is not modified with azobenzene. The specific implementation steps of S1 are as follows:

[0075] S1. Under dry nitrogen protection, 50 parts of trifluoropropylmethylcyclotrisiloxane and 0.05 parts of tetramethylammonium hydroxide were added to a reactor, and the temperature was raised to 90°C for reaction for 3 hours to obtain dihydroxy polytrifluoropropylmethylsiloxane; 33.3 parts of methylphenylcyclotrisiloxane were added, and the temperature was raised to 120°C and the reaction was continued for 5 hours; finally, the temperature was raised to 160°C and the reaction was removed under reduced pressure to obtain a fluorosilicone-phenylsiloxane block copolymer;

[0076] 100 parts of PTMG2000 (polytetramethylene ether glycol) and 22.2 parts of IPDI (isophorone diisocyanate) were reacted at 80°C for 3 hours, and then 7.6 parts of 4-hydroxymethylphenylboric acid and 0.05 parts of dibutyltin dilaurate were added and reacted at 70°C for 8 hours. The product was dissolved in tetrahydrofuran, precipitated in deionized water, and vacuum dried to obtain a borate-terminated polyurethane prepolymer;

[0077] S2. Add 100 parts of fluorosilicone-phenylsiloxane block copolymer and 25 parts of borate-terminated polyurethane into a planetary mixer and mix them evenly; add 12 parts of Nd@MOF-808 and 30 parts of CNT / TiO2 in three times, control the temperature to 40°C and mix evenly; stir and deaerate at -0.095 MPa vacuum for 30 minutes until no bubbles are visible; after cooling to 30°C, add 3 parts of photoinitiator 1173 and 1.5 parts of neodymium acetylacetonate, stir in the dark for 10 minutes to obtain a mixed slurry;

[0078] S3, the mixed slurry was injected into the mold and placed under a UV light source with a wavelength of 365nm (intensity of 80mW / cm 2 ) irradiated for 5 minutes; heated to 60 ° C and cured for 2 hours, continued to heat up to 80 ° C and cured for 2 hours, and finally heated to 110 ° C and cured for 4 hours to obtain a low-temperature resistant silicone elastic damping body.

[0079] The remaining raw materials and preparation process remain the same as in Example 1.

[0080] Comparative Example 5

[0081] The difference between this comparative example and Example 1 is that no gradient temperature curing is performed in S3; the specific implementation steps of S3 are:

[0082] S3, the mixed slurry was injected into the mold and placed under a UV light source with a wavelength of 365nm (intensity of 80mW / cm 2 ) irradiated for 5 minutes; heated to 110° C. and cured for 8 hours to obtain a low-temperature resistant silicone elastic damping body.

[0083] The remaining raw materials and preparation process remain the same as in Example 1.

[0084] Performance Testing

[0085] 1. According to GB / T 22567-2008 "Test Method for Determination of Glass Transition Temperature of Electrical Insulating Materials", the low-temperature-resistant silicone elastic damping bodies obtained in each embodiment and comparative example of this application were tested for minimum effective damping temperature and tan δ at -70°C;

[0086] 2. According to GB / T 9878-2008 "Fire Resistance Test Methods for Building Components", the low-temperature resistant organic silicone elastic damping bodies obtained in each embodiment and comparative example of this application were tested for effective damping temperature range;

[0087] 3. According to GB / T 528-2009 "Vulcanized rubber or thermoplastic rubber - Determination of tensile stress-strain properties", the self-healing efficiency of the low-temperature resistant silicone elastic damping bodies obtained in each embodiment and comparative example of this application was tested;

[0088] 4. According to GB / T 1041-2008 "Determination of Compression Properties of Plastics", the low-temperature resistant silicone elastic damping bodies obtained in each embodiment and comparative example of this application were tested for compression modulus (-60°C);

[0089] The results are shown in Table 1:

[0090] Table 1

[0091]

[0092] As shown in Table 1, Example 1 maintains effective damping (tan δ > 0.3) at -100°C, significantly outperforming Comparative Example 1 (-75°C) and Comparative Example 3 (-60°C), demonstrating that the trifluoropropyl flexible segments of the fluorosilicone-phenylsiloxane block copolymer successfully overcome the low-temperature embrittlement bottleneck of traditional phenyl silicone oils. At the extreme temperature of -70°C, the dissipation factor of Example 1 (tan δ = 0.35) is nearly doubled compared to Comparative Example 3 (0.18). This is attributed to the synergistic effect of the ultra-low rotation barrier of the fluorosilicone segments and the cohesive strength of the phenyl segments, which ensure the sustained motion of the molecular chains at low temperatures.

[0093] The effective damping temperature range of Example 1 reaches 82°C (-100°C to -18°C), far higher than all the comparative examples (47-65°C). This is attributed to the precise control of the gradient phase separation structure: the fluorosilicon phase region (Tg≈-110°C) dominates ultra-low temperature energy dissipation; the phenylsilicon phase region (Tg≈-70°C) connects to the medium-temperature damping; and the polyurethane phase region (Tg≈-40°C) covers the near-room temperature range. In Comparative Example 5 (which eliminates gradient curing), the temperature range is narrowed to 65°C, verifying the necessity of step temperature curing for phase structure formation.

[0094] Example 1 achieves a 90% self-repair rate at -40°C, while Comparative Example 2 (no borate bond) and Comparative Example 3 (no dynamic bond) completely lose their repair ability; the neodymium coordination bond provides rigid support, so that the compression modulus (-60°C) reaches 25MPa, an increase of 78% over Comparative Example 3 (14MPa), avoiding the loss of elasticity caused by excessive hardening.

[0095] Azobenzene-modified CNT / TiO2 improves damping efficiency through a stress response mechanism: the tanδ (0.35) of Example 1 is 40% higher than that of Comparative Example 4 (unmodified filler, tanδ = 0.25) due to the additional energy dissipation of the cis-trans isomers of the azobenzene group; the core-shell structure of the filler (TiO2-coated CNT) enhances interfacial bonding, maintaining a compression modulus of 25 MPa, which is better than 19 MPa in Comparative Example 4, solving the phase separation defect caused by traditional fillers.

[0096] The control experiments of Examples 2-5 reveal the performance balance point.

[0097] The above disclosures are only a few specific embodiments of the present invention. However, the embodiments of the present invention are not limited thereto. Any changes that can be conceived by those skilled in the art should fall within the scope of protection of the present invention.

Claims

1. A low-temperature resistant organic silicon elastic damper, characterized in that: The invention comprises, by weight, 95-110 parts of fluorosilicone-phenylsiloxane block copolymer, 25-35 parts of borate-terminated polyurethane prepolymer, 10-15 parts of Nd@MOF-808, 20-40 parts of azobenzene-modified CNT / TiO2, 2-4 parts of photoinitiator 1173 and 2-3 parts of neodymium acetylacetonate.

2. The low-temperature resistant organic silicon elastic damper according to claim 1, characterized in that: The fluorosilicone-phenylsilicone block copolymer is prepared by the following steps: Under nitrogen protection, trifluoropropylmethylcyclotrisiloxane and tetramethylammonium hydroxide are uniformly mixed, heated to 85-90°C and reacted for 3-4 hours to obtain dihydroxy polytrifluoropropylmethylsiloxane; then methylphenylcyclotrisiloxane is added, the temperature is raised to 115-120°C and the reaction is continued for 5-6 hours; finally, the temperature is raised to 155-160°C and the mixture is removed under reduced pressure to obtain a fluorosilicone-phenylsiloxane block copolymer.

3. The low-temperature resistant organic silicon elastic damper according to claim 2, characterized in that: The weight ratio of the trifluoropropylmethylcyclotrisiloxane, tetramethylammonium hydroxide and methylphenylcyclotrisiloxane is (45-55): (0.03-0.06): (30-35).

4. The low-temperature resistant organic silicon elastic damper according to claim 1, characterized in that: The borate-terminated polyurethane prepolymer is prepared by the following steps: PTMG2000 and IPDI were mixed and reacted at 75-80°C for 3-4 hours. 4-Hydroxymethylphenylboric acid and dibutyltin dilaurate were then added and reacted at 65-70°C for 8-9 hours. The product was dissolved in tetrahydrofuran, precipitated in deionized water, and vacuum dried to obtain a borate-terminated polyurethane prepolymer.

5. The low-temperature resistant organic silicon elastic damper according to claim 4, characterized in that: The weight ratio of the PTMG2000, IPDI, 4-hydroxymethylphenylboric acid and dibutyltin dilaurate is (95-110): (20-25): (6-9): (0.04-0.07).

6. The low-temperature resistant organic silicon elastic damper according to claim 1, characterized in that: The azobenzene-modified CNT / TiO2 is prepared by the following steps: CNTs are treated with mixed acid oxidation to obtain carboxylated CNTs; TiO2 is deposited on the surface of the carboxylated CNTs using TiCl4 and H2O as precursors at a temperature of 145-150°C, and the cycle is repeated 200-210 times to obtain TiO2@CNTs; HPAAB is reacted with SOCl2 to obtain HPAAB chloride; TiO2@CNTs and HPAAB chloride are refluxed in toluene for 12-14 hours to obtain azobenzene-modified CNT / TiO2.

7. The low-temperature resistant organic silicon elastic damper according to claim 6, characterized in that: The mixed acid is a mixture of H2SO4 and HNO3 in a volume ratio of 3:1; the TiO2 deposition thickness in the TiO2@CNT is 4-8nm.

8. A method for preparing a low-temperature resistant organic silicon elastic damper, characterized in that: The organic silicon elastic damping body according to any one of claims 1 to 7 comprises the following steps: S1. Mix fluorosilicone-phenylsiloxane block copolymer and borate-terminated polyurethane; add Nd@MOF-808 and azobenzene-modified CNT / TiO2 in batches, control the temperature and mix; stir and degas under vacuum; after cooling, add photoinitiator 1173 and neodymium acetylacetonate, stir in the dark, and obtain a mixed slurry; S2. Inject the mixed slurry into the mold and irradiate it under a UV light source with a wavelength of 300-400nm for 5-10 minutes; heat it to 55-60℃ and cure it for 2-2.5h, continue to heat it to 75-80℃ and cure it for 1.5-2h, and finally heat it to 105-110℃ and cure it for 4-4.5h to obtain a low-temperature resistant silicone elastic damping body.

9. The method for preparing a low-temperature resistant organic silicon elastic damper according to claim 8, characterized in that: The temperature of the temperature-controlled mixing is 40-45°C; the temperature of the cooling is 30-35°C.

10. The method for preparing a low-temperature resistant organic silicon elastic damper according to claim 8, characterized in that: The stirring and degassing time is 25-40 minutes; the light-proof stirring time is 10-15 minutes.

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