Wide-temperature-range damping acrylate elastomer and preparation method thereof

Abstract

The invention discloses a wide-temperature-range damping acrylate elastomer and a preparation method thereof. The acrylate elastomer has the following expression: A1B1B2B3A2, wherein A1 and A2 are alkyl methacrylate blocks, and the structures of A1 and A2 are the same or different; b1, B2 and B3 are alkyl acrylate blocks, and B1, B2 and B3 have the same or different structures. According to the invention, the multi-block acrylate elastomer polymer is synthesized by adopting the combination of multiple alkyl methacrylate monomers and alkyl acrylate monomers through an anionic polymerization method, and the polymer material has the advantages of good damping performance, wide damping temperature range, good mechanical property, flexibility, heat resistance, oil resistance and aging resistance, and can be widely applied to the field of damping materials. The material can be applied to shock absorption and noise reduction in the fields of rail transit, automobiles, aerospace and buildings.

Description

Technical Field

[0001] The invention belongs to the field of acrylic elastomers and synthesis thereof, and particularly relates to a wide-temperature-range damping acrylic elastomer and a preparation method thereof. Background Art

[0002] With the development of industry and the continuous improvement of people's quality of life, people are paying more and more attention to the hazards caused by mechanical vibration and noise. Vibration and noise not only affect people's physical and mental health, but also cause damage to instruments, machinery, equipment, and pipelines. To reduce the adverse consequences of vibration and noise, barrier materials are often used to separate the vibration from the vibration source, mitigate the vibration of the vibrating body, and thus achieve the purpose of damping, shock absorption, and noise reduction.

[0003] High-damping shock-absorbing materials are usually composed of synthetic rubber-like polymer materials or polymer gel materials. The reason why rubber-like polymer materials, such as styrene-butadiene rubber (SBR), butyl rubber (IIR), nitrile rubber (NBR), silicone rubber (PDMS), ethylene-propylene rubber (EPR), polyurethane elastomer (TPU), etc., can achieve the effect of damping and shock absorption is that under the action of alternating stress (such as vibration), the chain segment movement of the polymer chain macromolecules needs to overcome resistance, which takes a certain amount of time. Therefore, the deformation often lags behind the change of stress. Within a certain frequency and temperature range, this lag phenomenon is very obvious. The subsequent deformation recovery means that a large resistance needs to be overcome. At this time, the external force will be converted into heat energy and dissipated. The amplitude of the structural vibration will decrease along with the dissipation of energy, thereby achieving the purpose of damping and shock absorption and noise reduction.

[0004] Acrylate thermoplastic elastomers are block copolymers based on the copolymerization of (meth)acrylate monomers. Their backbone is a saturated alkane, with polar ester pendant groups. This imparts excellent properties such as heat resistance, oil resistance, ozone resistance, aging resistance, and UV resistance. Acrylate elastomers offer superior mechanical and processing properties to fluororubber and silicone rubber, and superior heat, oxidation, and oil resistance to nitrile rubber. Therefore, they can partially replace expensive fluororubber to reduce costs, or replace nitrile rubber in some applications to improve product performance. They are a high-performance, high-temperature, oil-resistant specialty material with a high cost-effectiveness ratio.

[0005] However, currently, single elastomers / rubbers have only a single glass transition temperature (GTT), generally exhibit low damping factors, and have a narrow damping temperature range. While composite materials obtained by compounding with rubbers can improve damping performance, the preparation process is complex and costly. Therefore, there is an urgent need to find a multi-block acrylic elastomer with multiple GTTs and a wide damping temperature range, while also being simple to prepare and suitable for large-scale industrial production. Summary of the Invention

[0006] To address the problems of existing rubber-based damping materials, which generally suffer from insufficient damping loss factors and a narrow damping temperature range, making it difficult to produce high-damping materials with a wide temperature range, the first objective of the present invention is to provide a wide-temperature-range damping acrylic elastomer. This elastomer, a multi-block acrylic elastomer polymer, exhibits excellent damping performance and a wide damping temperature range. It also possesses excellent mechanical properties, flexibility, and resistance to heat, oil, and aging. It can be used for vibration and noise reduction in rail transit, automotive, aerospace, and construction.

[0007] The second object of the present invention is to provide a method for preparing a damping acrylic elastomer with a wide temperature range, which has simple operation, mild conditions and low production cost, and the method does not require vulcanization.

[0008] In order to achieve the above technical objectives, the present invention provides a wide-temperature-range damping acrylic elastomer, which has the following expression: A1B1B2B3A2; wherein A1 and A2 are methacrylate alkyl ester blocks, and the structures of A1 and A2 are the same or different; B1, B2 and B3 are acrylate alkyl ester blocks, and the structures of B1, B2 and B3 are the same or different.

[0009] The alkyl methacrylate monomers used in the blocks of the present invention have a rich variety of monomer types (different side chain ester groups), and due to the presence of large steric ester groups and side methyl groups on the side chains, the internal friction of the macromolecular segment movement is increased, the efficiency of converting external force into heat energy dissipation is improved, and good damping performance is exhibited, so that the acrylic elastomer has a wider glass transition temperature range (-50 to 200 ° C). At the same time, by combining a variety of alkyl methacrylate monomers and alkyl acrylate monomers, and the multi-blocks are arranged in a certain order; wherein the A1 block and the A2 block can be the same or different, and the B1 block, the B2 block and the B3 block can be the same or different; the multi-block acrylic elastomer obtained by compounding has at least one glass transition temperature (Tg), so that the material maintains good elasticity and damping properties (good damping performance and wide damping temperature range) over a wide temperature range, and also has good mechanical properties, flexibility and heat resistance, oil resistance, and aging resistance. It can be used in vibration and noise reduction in rail transportation, automobiles, aerospace, and construction.

[0010] Secondly, the acrylic elastomer structure of the present invention consists of alkyl methacrylate monomers at both ends and alkyl acrylate monomers in the middle. This design is based on the fact that alkyl methacrylate and alkyl acrylate are incompatible. Therefore, the alkyl methacrylate blocks at the beginning and end and the alkyl acrylate block in the middle will cause phase separation, forming a "sea-island" structure with alkyl methacrylate blocks as microdomains uniformly dispersed in a continuous phase of alkyl acrylate blocks. This structure is the basis for the material's excellent mechanical properties. The middle alkyl acrylate block is a combination of multiple blocks B1, B2, and B3. Compared with a combination of alkyl methacrylate in the middle and alkyl acrylate at the beginning and end, the blocks have better compatibility, resulting in the material exhibiting better damping and mechanical properties.

[0011] The inventors discovered that when a polymer consists solely of alkyl methacrylate monomers in a block, it forms a plastic similar to PMMA. However, its properties differ significantly from those of elastomers, and the performance testing standards are completely different, making them incomparable. Furthermore, polymers consisting solely of alkyl acrylate monomers in a block generally have a low glass transition temperature and virtually no strength.

[0012] As a preferred solution, the alkyl methacrylate block is obtained by polymerization of methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, n-hexyl methacrylate, n-octyl methacrylate, isooctyl methacrylate, dodecyl methacrylate, tridecyl methacrylate or stearic methacrylate.

[0013] As a preferred solution, the alkyl acrylate block is obtained by polymerization of methyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, n-octyl acrylate or isooctyl acrylate.

[0014] As a preferred solution, the molar ratio of the alkyl methacrylate monomer to the alkyl acrylate monomer is 1:(1-10). The molar fraction of the A1 block unit in the acrylic elastomer is 10-30%, the molar fraction of the A2 block unit is 10-30%, the molar fraction of the B1 block unit is 20-50%, the molar fraction of the B2 block unit is 5-20%, and the molar fraction of the B3 block unit is 20-50%. The content of each block in the present invention jointly affects the mechanical properties and damping properties of the elastomer. When the content of the A1 and A2 blocks at both ends increases, the strength and hardness of the elastomer increase, and the elongation decreases. The combination of different types of alkyl acrylate monomers can change the width of the damping temperature range. The change in the ratio of the B1, B2, and B3 block units can adjust the range of the temperature range. At the same time, the content of the B2 block unit will affect the peak value of the damping factor tanδ.

[0015] As a preferred solution, the molecular weight of the acrylic elastomer is 10,000 to 500,000 g / mol; and the molecular weight distribution PDI of the acrylic elastomer is 1.1 to 2.0.

[0016] The present invention also provides a method for preparing a wide-temperature-range damping acrylic elastomer. The method comprises the following steps: adding a solvent, an activator, a co-catalyst, and an initiator into an anhydrous and oxygen-free polymerization reactor, heating the reactor to an initial polymerization temperature, sequentially adding an A1 block monomer, a B1 block monomer, a B2 block monomer, a B3 block monomer, and an A2 block monomer, and performing five-stage polymerization to obtain an A1B1B2B3A2 type acrylic elastomer glue; and subjecting the A1B1B2B3A2 type acrylic elastomer glue to quenching, coagulation, and vacuum drying.

[0017] The present invention creates a suitable reaction environment by mixing components such as a solvent, an activator, a co-catalyst, and an initiator. The solvent provides a medium for thorough mixing of the monomers and other components, while the activator and co-catalyst help regulate the activity of the initiator and the rate of the polymerization reaction. By sequentially adding a variety of specific alkyl methacrylate monomers and alkyl acrylate monomers, the structure and composition of the polymer chain can be controlled, allowing the design of polymer chains that meet the specific physical and chemical properties of the damping material. These blocks with different functionalities can adjust the polymer's glass transition temperature (Tg) or glass transition range on a macroscopic scale, thereby maintaining good elasticity and damping properties over a wide temperature range.

[0018] As a preferred solution, the solvent is at least one of benzene, toluene, ethylbenzene, xylene, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethoxymethane, tetrahydrofuran and dioxane.

[0019] As a preferred solution, the activator is at least one of pentamethyldiethylenetriamine, pentamethyldipropylenetriamine, hexamethylphosphoric triamide and N,N,N',N'-tetramethylethylenediamine.

[0020] As a preferred solution, the co-catalyst is prepared by mixing AlR3 with a phenolic reagent in a molar ratio of 1:(1-5). The present invention uses a compound of AlR3 and a phenolic reagent to produce a ligand with large steric hindrance, which reacts with the initiator, reducing the activity of the initiator, thereby inhibiting the occurrence of side reactions and obtaining a polymer with a controllable molecular weight distribution.

[0021] As a preferred solution, the AlR3 is one of triethylaluminum, trimethylaluminum, triisobutylaluminum (i-BuAl), diethylaluminum monochloride, ethylaluminum dichloride and methylaluminoxane.

[0022] As a preferred embodiment, the phenolic reagent is at least one of 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-p-methylphenol (BHT), 2,6-di-tert-butyl-p-ethylphenol, 2,4,6-tri-tert-butylphenol, 2,6-diisopropylphenol, 2-tert-butylphenol, 2-tert-butyl-5-methylphenol and 2,6-di-tert-butyl-4-nitrophenol.

[0023] As a preferred solution, the initiator is one of n-butyl lithium (n-BuLi), sec-butyl lithium (s-BuLi), and tert-butyl lithium (t-BuLi).

[0024] As a preferred solution, the molar ratio of the co-catalyst to the initiator is (50-1):1; the molar ratio of the activator to the initiator is 1:(1-150); the molar ratio of the initiator to the sum of the comonomer A1 block, A2 block, B1 block, B2 block and B3 block is 1:(100-5000); the mass ratio of the sum of the comonomer A1 block, A2 block, B1 block, B2 block and B3 block to the solvent is 1:(2-10).

[0025] As a preferred solution, the conditions for the one-stage polymerization and the five-stage polymerization are independently selected from: temperature of -50 to 70°C and time of 0.5 to 3 hours; the conditions for the two-stage polymerization, the three-stage polymerization and the four-stage polymerization are independently selected from: temperature of -50 to 70°C and time of 0.5 to 1 hour.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1) Compared with a single rubber or elastomer having only one glass transition temperature and a generally smaller damping factor and a narrower damping temperature range, the composite material obtained by compounding rubber has improved damping performance, but the preparation process is complicated and the cost is high. The multi-block acrylic elastomer material of a specific order provided by the present invention has multiple glass transition temperatures (Tg) or a wider glass transition range, good damping performance, a wide damping temperature range, and excellent damping performance between -40 and 50°C. In addition, the multi-block acrylic elastomer material has good mechanical properties, flexibility, and heat resistance, oil resistance, and aging resistance without the need for vulcanization, and can be used in vibration reduction and noise reduction in rail transportation, automobiles, aerospace, and construction.

[0028] 2) The preparation process of the present invention is simple, and a multi-block acrylic elastomer is synthesized by an anionic polymerization method. The prepared elastomer has good performance and high application value.

[0029] 3) In the elastomer structure of the present invention, by designing the ends to be composed of alkyl methacrylate monomers and the middle position to be composed of alkyl acrylate monomers, phase separation occurs, forming a "sea-island" structure in which the alkyl methacrylate blocks are uniformly dispersed as micro-regions in the alkyl acrylate blocks as a continuous phase, greatly improving the mechanical properties of the elastomer. At the same time, the position and width of the damping temperature range can be adjusted by the combination of B1, B2 and B3 multi-blocks. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The multi-block acrylic elastomer in Example 1 of the present invention 1 H NMR spectrum.

[0031] Figure 2 This is the GPC chart of the multi-block acrylic elastomer in Example 1 of the present invention.

[0032] Figure 3 This is the DSC graph of the multi-block acrylic elastomer in Example 1 of the present invention.

[0033] Figure 4 This is the DMA diagram of the multi-block acrylic elastomer in Example 1 of the present invention. The damping performance of the polymer material is mainly characterized by the damping factor tanδ. The larger the damping factor tanδ, the better the damping performance of the material. As a damping and shock-absorbing material, tanδ is generally required to be greater than 0.3. DETAILED DESCRIPTION

[0034] The present invention is further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments. Obviously, the embodiments described below are only a part of the embodiments, and all other embodiments obtained by professionals in this field without making creative efforts are still within the scope of protection of the present invention.

[0035] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0036] Example 1

[0037] 500 mL of toluene solvent was added to a polymerization kettle replaced with dry nitrogen, stirring was started, the temperature in the polymerization kettle was maintained at 25 ° C, the pressure was 0.4 MPa, and the activator hexamethylphosphoric triamide (24.0 mL, 137.5 mmol, 55 equiv.), the co-catalyst i-BuAl(BHT)2 (prepared by Al(i-Bu)3 and BHT in a molar ratio of 1:1.7) (22.5 mL, 20.0 mmol, 8 equiv.), and the initiator s-BuLi (2.0 mL, 2.5 mmol, 1 equiv.) were added, and then the monomer methyl methacrylate (MMA) (17.6 mL, 165 mmol, 66 equiv.) was slowly added. After the reaction for 1 h, the glue was pressed into the low-temperature polymerization kettle and the monomer isobutyl acrylate (iBA) (39.6 The mixture was stirred at -30°C for 1 h, and methyl acrylate (MA) (14.9 mL, 165 mmol, 66 equiv.) was added and stirred at -30°C for 1 h. Then, n-butyl acrylate (nBA) (71.0 mL, 495 mmol, 198 equiv.) was added and stirred at -30°C for 1 h. The resulting mixture was then pressed into a room temperature polymerization kettle, and methyl methacrylate (MMA) (17.6 mL, 165 mmol, 66 equiv.) was added. The mixture was stirred at 25°C for 3 h, and an appropriate amount of methanol was added for quenching. The resulting mixture was then placed in a coagulation tank and heated with medium-pressure steam to remove the toluene solvent. The mixture was then sealed and boiled for 30 min. Finally, the mixture was dried in a vacuum oven to constant weight to obtain a multi-block acrylic elastomeric polymer.

[0038] Example 2

[0039] 500 mL of toluene solvent was added to a polymerization kettle replaced with dry nitrogen, stirring was started, the temperature in the polymerization kettle was maintained at 25 ° C, the pressure was 0.4 MPa, and the activator hexamethylphosphoric triamide (28.8 mL, 165 mmol, 55 equiv.), the co-catalyst i-BuAl(BHT)2 (prepared by Al(i-Bu)3 and BHT in a molar ratio of 1:1.7) (27.0 mL, 24.0 mmol, 8 equiv.), and the initiator s-BuLi (2.4 mL, 3.0 mmol, 1 equiv.) were added, and then the monomer methyl methacrylate (18.3 mL, 171 mmol, 57 equiv.) was slowly added. After the reaction for 1 h, the rubber was pressed into the low-temperature polymerization kettle and the monomer n-butyl acrylate (57.2 The mixture was stirred at -30°C for 1 h, and then methyl acrylate (6.2 mL, 68.4 mmol, 22.8 equiv.) was added and stirred at -30°C for 1 h. Then, n-butyl acrylate (57.2 mL, 399 mmol, 133 equiv.) was added and stirred at -30°C for 1 h. After that, the gel was pressed into a room temperature polymerization kettle, and methyl methacrylate (18.3 mL, 171 mmol, 57 equiv.) was added. The mixture was stirred at 25°C for 3 h, and an appropriate amount of methanol was added for quenching. The gel was then added to a coagulation tank and heated with medium-pressure steam to remove the toluene solvent. The gel was then sealed and boiled for 30 min. Finally, it was dried in a vacuum oven to constant weight to obtain a multi-block acrylic elastomeric polymer.

[0040] Example 3

[0041] 500 mL of toluene solvent was added to a polymerization kettle replaced with dry nitrogen, stirring was started, the temperature in the polymerization kettle was maintained at 25 ° C, and the pressure was 0.4 MPa. The activator hexamethylphosphoric triamide (24.0 mL, 137.5 mmol, 55 equiv.), the co-catalyst i-BuAl(BHT)2 (prepared by Al(i-Bu)3 and BHT in a molar ratio of 1:1.7) (22.5 mL, 20.0 mmol, 8 equiv.), and the initiator s-BuLi (2.0 mL, 2.5 mmol, 1 equiv.) were added, and then the monomer methyl methacrylate (17.6 mL, 165 mmol, 66 equiv.) was slowly added. After the reaction for 1 h, the glue was pressed into the low-temperature polymerization kettle and the monomer isobutyl acrylate (55.4 mL) was added. L, 385 mmol, 154 equiv.), stirred and reacted at -30°C for 1 h, then isopropyl acrylate (iPA) (21.1 mL, 165 mmol, 66 equiv.) was added and stirred and reacted at -30°C for 1 h. Then, n-butyl acrylate (71.0 mL, 495 mmol, 198 equiv.) was added and stirred and reacted at -30°C for 1 h. The gel was then pressed into a room temperature polymerization kettle, and methyl methacrylate monomer (17.6 mL, 165 mmol, 66 equiv.) was added. The reaction was stirred and reacted at 25°C for 3 h. An appropriate amount of methanol was added for quenching. The gel was then placed in a coagulation tank and heated with medium-pressure steam to remove the toluene solvent. The gel was sealed and boiled for 30 min. Finally, it was dried in a vacuum oven to constant weight to obtain a multi-block acrylic elastomeric polymer.

[0042] Example 4

[0043] 500 mL of toluene solvent was added to a polymerization kettle replaced with dry nitrogen, stirring was started, the temperature in the polymerization kettle was maintained at 25 ° C, and the pressure was 0.4 MPa. The activator hexamethylphosphoric triamide (24.0 mL, 137.5 mmol, 55 equiv.), the co-catalyst i-BuAl(BHT)2 (prepared by mixing Al(i-Bu)3 and BHT in a molar ratio of 1:1.7) (22.5 mL, 20.0 mmol, 8 equiv.), and the initiator s-BuLi (2.0 mL, 2.5 mmol, 1 equiv.) were added, and then the monomer methyl methacrylate (19.3 mL, 180 mmol, 72 equiv.) was slowly added. After reacting for 1 h, the glue was pressed into the low-temperature polymerization kettle and the monomer isobutyl acrylate (60.5 mL) was added. , 420 mmol, 168 equiv.), stirred and reacted at -30°C for 1 h, and then cyclohexyl acrylate (CHA) (11.4 mL, 72 mmol, 28.8 equiv.) was added and stirred and reacted at -30°C for 1 h. Then, n-butyl acrylate (60.2 mL, 420 mmol, 168 equiv.) was added and stirred and reacted at -30°C for 1 h. The glue was then pressed into a room temperature polymerization kettle, methyl methacrylate monomer (19.3 mL, 180 mmol, 72 equiv.) was added and stirred and reacted at 25°C for 3 h. An appropriate amount of methanol was added for quenching. The glue was then added to a coagulation tank, heated by passing medium-pressure steam to remove the toluene solvent, and the glue was sealed and boiled for 30 min. Finally, it was dried in a vacuum oven to constant weight to obtain a multi-block acrylic elastomeric polymer.

[0044] Example 5

[0045] 500 mL of toluene solvent was added to a polymerization kettle replaced with dry nitrogen, and stirring was started. The temperature in the polymerization kettle was maintained at 25°C and the pressure was 0.4 MPa. The activator hexamethylphosphoric triamide (28.8 mL, 165.0 mmol, 55 equiv.), the co-catalyst i-BuAl(BHT)2 (prepared by mixing Al(i-Bu)3 and BHT in a molar ratio of 1:1.7) (27.0 mL, 24.0 mmol, 8 equiv.), and the initiator s-BuLi (2.4 mL, 3.0 mmol, 1 equiv.) were added. Then, the monomer methyl methacrylate (15.4 mL, 144 mmol, 48 equiv.) was slowly added. After reacting for 1 h, the rubber was pressed into a low-temperature polymerization kettle, and n-butyl acrylate (48.1 mL, The mixture was stirred at -30°C for 1 h, and then isobutyl acrylate (20.8 mL, 144 mmol, 48 equiv.) was added and stirred at -30°C for 1 h. Then, isooctyl acrylate (EHA) (70.0 mL, 336 mmol, 112 equiv.) was added and stirred at -30°C for 1 h. The resulting mixture was then pressed into a room temperature polymerization kettle, and methyl methacrylate (15.4 mL, 144 mmol, 48 equiv.) was added. The mixture was stirred at 25°C for 3 h, and an appropriate amount of methanol was added for quenching. The resulting mixture was then placed in a coagulation tank and heated with medium-pressure steam to remove the toluene solvent. The mixture was sealed and boiled for 30 min. Finally, the mixture was dried in a vacuum oven to constant weight to obtain a multi-block acrylic elastomeric polymer.

[0046] Comparative Example 1

[0047] 500 mL of toluene solvent was added to a polymerization reactor replaced with dry nitrogen, and stirring was started. The temperature in the polymerization reactor was kept at 25 ° C and the pressure was 0.4 MPa. The activator hexamethylphosphoric triamide (24.0 mL, 137.5 mmol, 55 equiv.), the co-catalyst i-BuAl(BHT)2 (prepared by Al(i-Bu)3 and BHT in a molar ratio of 1:1.7) (22.5 mL, 20.0 mmol, 8 equiv.), and the initiator s-BuLi (2.0 mL, 2.5 mmol, 1 equiv.) were added. Then, the monomer methyl methacrylate (19.3 mL, 180 mmol, 72 equiv.) was slowly added. After the reaction for 1 h, The glue was pressed into a low-temperature polymerization kettle, and isobutyl acrylate (60.5 mL, 420 mmol, 168 equiv.) was added. The mixture was stirred and reacted at -30°C for 1 h. Then, n-butyl acrylate (60.2 mL, 420 mmol, 168 equiv.) was added. The mixture was stirred and reacted at -30°C for 1 h. The glue was then pressed into a room-temperature polymerization kettle, and methyl methacrylate (19.3 mL, 180 mmol, 72 equiv.) was added. The mixture was stirred and reacted at 25°C for 3 h. An appropriate amount of methanol was added for quenching. The glue was then added to a coagulation tank, heated with medium-pressure steam to remove the toluene solvent, and the glue was sealed and boiled for 30 min. Finally, it was dried in a vacuum oven to constant weight to obtain a multi-block acrylic elastomeric polymer.

[0048] Comparative Example 2

[0049] 500 mL of toluene solvent was added to a polymerization kettle replaced with dry nitrogen, and stirring was started. The temperature in the polymerization kettle was maintained at 25°C and the pressure was 0.4 MPa. The activator hexamethylphosphoric triamide (33.6 mL, 192.5 mmol, 55 equiv.), the co-catalyst i-BuAl(BHT)2 (prepared by mixing Al(i-Bu)3 and BHT in a molar ratio of 1:1.7) (31.5 mL, 28.0 mmol, 8 equiv.), and the initiator s-BuLi (2.8 mL, 3.5 mmol, 1 equiv.) were added. Then, the monomer methyl methacrylate (28.5 mL, 266 mmol, 76 equiv.) was slowly added. After reacting for 1 h, the glue was pressed into the low-temperature polymerization kettle, and the monomer isobutyl acrylate (19.2 mL, 133 mmol, 3 8 equiv.), stirred and reacted at -30°C for 1 h, then the glue was pressed into a room temperature polymerization kettle, methyl methacrylate monomer (21.3 mL, 199.5 mmol, 57 equiv.) was added, stirred and reacted at 25°C for 2 h, then the glue was pressed into a low-temperature polymerization kettle again, n-butyl acrylate (66.7 mL, 465.5 mmol, 133 equiv.) was added, stirred and reacted at -30°C for 1 h, then the glue was pressed into a room temperature polymerization kettle, methyl methacrylate monomer (28.5 mL, 266 mmol, 76 equiv.) was added, stirred and reacted at 25°C for 3 h, and an appropriate amount of methanol was added for quenching. The glue was then added to a coagulation tank, heated with medium-pressure steam to remove the toluene solvent, and the glue was sealed and boiled for 30 min. Finally, it was dried in a vacuum oven to constant weight to obtain a multi-block acrylic elastomeric polymer.

[0050] The microstructure and composition of the multiblock acrylic elastomeric polymers obtained in Examples 1-5 and Comparative Examples 1-2 were characterized, with the microstructure being characterized by nuclear magnetic resonance (NMR) and the molecular weight being measured by gel permeation chromatography (GPC). The test results are shown in Table 1.

[0051] The multiblock acrylic elastomeric polymers obtained in Examples 1-5 and Comparative Examples 1-2 were tested for tensile properties, hardness, thermal properties, and damping properties. Tensile properties were measured using a universal testing machine in accordance with GB / T528-2009 at a tensile rate of 500 mm / min; hardness was measured using a Shore A durometer in accordance with GB / T531.1-2008; thermal properties were measured using a differential scanning calorimeter (DSC) at a temperature range of -150°C to 150°C and a ramp rate of 10°C / min; and damping properties were measured using a dynamic mechanical analyzer (DMA) at a temperature range of -60°C to 100°C, a ramp rate of 3°C / min, a frequency of 11 Hz, and a strain of 0.3%. The test results are shown in Table 2.

[0052] Table 1 Microstructure and composition of the multi-block acrylic elastomers obtained in Examples 1 to 5 and Comparative Examples 1 to 2

[0053]

[0054] Table 2 Performance test results of the multi-block acrylic elastomers obtained in Examples 1 to 5 and Comparative Examples 1 to 2

[0055]

[0056] A comparison of the data in Tables 1 and 2 shows that when the structure in Comparative Example 1 is A1B1B3A2, the lack of a B2 block in the structure results in a decrease in the polymer's strength and hardness, and a significant narrowing of the damping temperature range. In contrast, when the structure in Comparative Example 2 is A1B1A3B3A2, i.e., when the third block is an alkyl methacrylate block, the material's damping performance significantly decreases.

Claims

1. A wide temperature range damping acrylic elastomer, characterized by: The acrylic elastomer has the following formula: A1B1B2B3A2; in, A1 and A2 are alkyl methacrylate blocks, and the structures of A1 and A2 are the same or different; B1, B2 and B3 are alkyl acrylate blocks, and the structures of B1, B2 and B3 are the same or different.

2. The method for preparing a wide temperature range damping acrylic elastomer according to claim 1, characterized in that: The alkyl methacrylate block is obtained by polymerizing methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, n-hexyl methacrylate, n-octyl methacrylate, isooctyl methacrylate, dodecyl methacrylate, tridecyl methacrylate or stearic methacrylate.

3. The method for preparing a wide temperature range damping acrylic elastomer according to claim 1 or 2, characterized in that: The alkyl acrylate block is obtained by polymerizing methyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, n-octyl acrylate or isooctyl acrylate.

4. The method for preparing a wide temperature range damping acrylic elastomer according to claim 3, characterized in that: The molar ratio of the alkyl methacrylate monomer to the alkyl acrylate monomer is 1:(1-10); the molar fraction of the A1 block unit in the acrylic elastomer is 10-30%, the molar fraction of the A2 block unit is 10-30%, the molar fraction of the B1 block unit is 20-50%, the molar fraction of the B2 block unit is 5-20%, and the molar fraction of the B3 block unit is 20-50%.

5. The method for preparing a wide temperature range damping acrylic elastomer according to claim 1, characterized in that: The molecular weight of the acrylic elastomer is 10,000 to 500,000 g / mol; The molecular weight distribution PDI of the acrylic elastomer is 1.1-2.

0.

6. The method for preparing a wide temperature range damping acrylic elastomer according to any one of claims 1 to 5, characterized in that: After adding a solvent, an activator, a co-catalyst and an initiator into a polymerization reaction kettle in an anhydrous and oxygen-free state, the temperature is raised to the initial polymerization temperature, and an A1 block monomer, a B1 block monomer, a B2 block monomer, a B3 block monomer and an A2 block monomer are added in sequence to carry out five-stage polymerization to obtain an A1B1B2B3A2 type acrylic elastomer glue; the A1B1B2B3A2 type acrylic elastomer glue is subjected to quenching, coagulation and vacuum drying to obtain the obtained product.

7. The method for preparing a wide temperature range damping acrylic elastomer according to claim 6, characterized in that: The solvent is at least one of benzene, toluene, ethylbenzene, xylene, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethoxymethane, tetrahydrofuran and dioxane.

8. The method for preparing a wide temperature range damping acrylic elastomer according to claim 6, characterized in that: The activator is at least one of pentamethyldiethylenetriamine, pentamethyldipropylenetriamine, hexamethylphosphoric triamide and N,N,N',N'-tetramethylethylenediamine.

9. The method for preparing a wide temperature range damping acrylic elastomer according to claim 6, characterized in that: The co-catalyst is prepared by mixing AlR3 and phenolic reagent in a molar ratio of 1:(1-5); The AlR3 is one of triethylaluminum, trimethylaluminum, triisobutylaluminum, diethylaluminum monochloride, ethylaluminum dichloride and methylaluminoxane.

10. The method for preparing a wide temperature range damping acrylic elastomer according to claim 9, characterized in that: The phenolic reagent is at least one of 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-p-methylphenol, 2,6-di-tert-butyl-p-ethylphenol, 2,4,6-tri-tert-butylphenol, 2,6-diisopropylphenol, 2-tert-butylphenol, 2-tert-butyl-5-methylphenol and 2,6-di-tert-butyl-4-nitrophenol.

11. The method for preparing a wide temperature range damping acrylic elastomer according to claim 6, characterized in that: The initiator is n-butyl lithium, sec-butyl lithium or tert-butyl lithium.

12. The method for preparing a wide temperature range damping acrylic elastomer according to claim 6, characterized in that: The molar ratio of the co-catalyst to the initiator is (50-1):1; The molar ratio of the activator to the initiator is 1:(1-150); The molar ratio of the initiator to the sum of the comonomers A1 block, A2 block, B1 block, B2 block and B3 block is 1:(100-5000); The mass ratio of the sum of the comonomer A1 block, A2 block, B1 block, B2 block and B3 block to the solvent is 1:(2-10).

13. The method for preparing a wide temperature range damping acrylic elastomer according to claim 6, characterized in that: The conditions for the one-stage polymerization and the five-stage polymerization are independently selected from: temperature of -50 to 70°C and time of 0.5 to 3 hours; the conditions for the two-stage polymerization, the three-stage polymerization and the four-stage polymerization are independently selected from: temperature of -50 to 70°C and time of 0.5 to 1 hour.

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