A multi-arm acrylate elastomer, its preparation method and application

Abstract

A multi-arm acrylate elastomer, its preparation method, and its applications are disclosed. This invention belongs to the field of acrylate polymers. The purpose of this invention is to propose a novel coupling reaction system for the coupling reaction of diblock acrylate polymers. By adjusting the type and dosage of the coupling agent, the degree of coupling can be controlled to obtain a multi-arm acrylate elastomer. Specifically, under anhydrous and oxygen-free conditions, a solvent, catalyst, initiator, alkyl methacrylate monomer, and alkyl acrylate monomer are added sequentially, and the reaction is allowed to proceed for a sufficient time to polymerize and generate a diblock polymer. Then, a coupling agent is added to the reaction system, and the coupling reaction is continued for a certain time to obtain the multi-arm acrylate elastomer. The multi-arm acrylate elastomer of this invention possesses excellent viscosity, environmental friendliness, and mechanical properties, and can be applied in fields such as medicine, children's toys, and food packaging.

Description

Technical Field

[0001] This invention belongs to the field of acrylate polymers, specifically relating to a multi-arm acrylate elastomer, its preparation method, and its application. Background Technology

[0002] Thermoplastic elastomers (TPEs) are a new type of rubber material that becomes fluid when heated and subjected to shear forces, but recovers its original structure and stability upon cooling. Unlike ordinary thermosetting rubbers, which are chemically cross-linked and cannot return to their original state after deformation, thermoplastic elastomers are purely physically cross-linked. This allows the material to recover its original properties through heating after deformation, meaning that thermoplastic elastomers are recyclable materials; even after multiple uses, they can be reprocessed to regain their original properties. Acrylic thermoplastic elastomers, with a main chain of saturated alkanes and polar ester side groups, are attracting increasing attention as an emerging class of elastomers with excellent light transmission, oil resistance, and sealing properties. However, due to limitations in manufacturing technology, research on multi-arm acrylic elastomers is still in its early stages.

[0003] Existing research has revealed that coupled multi-arm polymers exhibit superior processing properties. Due to the high purity and absence of residual contaminants in post-processing and finishing agents, these polymers can also be used in medical and food materials. Furthermore, coupled multi-arm polymers possess improved viscosity, environmental friendliness, and mechanical properties, making them suitable for use as viscosity index improvers. They also exhibit good light transmittance, ductility, and environmental friendliness, making them applicable to injection molding tools and children's toys. However, current research on multi-arm star polymers primarily focuses on conjugated dienes and styrene monomers, with little exploration into the coupling of acrylate elastomers. This is mainly because acrylate monomers are more difficult to couple than conjugated diene monomers. The carbonyl groups on acrylate monomers can interact with the coupling agent to some extent, affecting coupling efficiency.

[0004] Patent CN 103282409 B proposes a coupling method for conjugated diene polymers, achieving coupling through an organosilane coupling agent. However, this method suffers from cumbersome procedures and excessively long reaction times, requiring multiple additions to complete the coupling. Patent CN 112135873 B proposes a coupling method using organosiloxanes as coupling agents, achieving coupling of conjugated diene polymers. However, its drawback is a high coupling temperature, with an optimal temperature of 90℃. Such high reaction temperatures result in high energy consumption for large-scale industrial production. Furthermore, existing coupling systems are mostly implemented in polyene polymer systems. Developing a mild and efficient coupling system for the preparation of multi-arm acrylate thermoplastic elastomers will provide technical support for developing new avenues for the industrial application of acrylate thermoplastic elastomers. Summary of the Invention

[0005] The purpose of this invention is to propose a novel coupling reaction system for the coupling reaction of diblock acrylate polymers. By adjusting the type and dosage of the coupling agent, the degree of coupling can be controlled to obtain a multi-arm acrylate elastomer, namely a multi-arm acrylate elastomer, its preparation method and application.

[0006] One objective of this invention is to provide a method for preparing a multi-arm acrylate elastomer, the method comprising the following steps:

[0007] S1: Under anhydrous and oxygen-free conditions, solvent, catalyst, initiator, alkyl methacrylate monomer and alkyl acrylate monomer are added sequentially. After a certain time of polymerization, a diblock polymer of alkyl methacrylate-alkyl acrylate with anionic initiation sites at the end is generated, and its general structural formula is AB.

[0008] S2: After the polymerization reaction is completed, continue to add coupling agent to the reaction system, and after a certain period of coupling reaction, obtain multi-arm acrylate elastomer.

[0009] Further specifying, the alkyl methacrylates mentioned in S1 include, but are not limited to, one or more 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, and stearate methacrylate, with the following structures:

[0010]

[0011] Further specifying, the alkyl acrylates mentioned in S1 include, but are not limited to, one or more of n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-hexyl acrylate, n-octyl acrylate, and isooctyl acrylate, with the following structure:

[0012]

[0013] Further specifying, the solvent mentioned in S1 is one or more of toluene, ethylbenzene, xylene, benzene, N,N'-dimethylformamide, dimethyl sulfoxide, ethylene glycol dimethyl ether, tetrahydrofuran, dioxane, and methyl tert-butyl ether in any proportion.

[0014] Furthermore, the solvent in S1 is a mixture of toluene and ethylene glycol dimethyl ether in a volume ratio of 30:1.

[0015] Further specified, the total mass ratio of alkyl methacrylate monomers and alkyl acrylate monomers in S1 to the mass ratio of solvent is 1:(1-10).

[0016] Furthermore, the total mass ratio of alkyl methacrylate monomers and alkyl acrylate monomers in S1 to the mass ratio of solvent is 1:(1-3).

[0017] Further specified, the total molar ratio of alkyl methacrylate monomers and alkyl acrylate monomers in S1 to the molar ratio of catalyst and initiator is 2000:(1-500):(0.5-4).

[0018] Furthermore, the total molar ratio of alkyl methacrylate monomers and alkyl acrylate monomers in S1 to the molar ratio of catalyst and initiator is 725:8:1.

[0019] Further specifying, the polymerization reaction temperature in S1 is -50 to 70°C, and the reaction time is 3 to 10 hours.

[0020] Furthermore, the polymerization reaction in S1 is limited to a temperature of -30 to 25°C and a time of 2 hours.

[0021] Further specifying, the coupling agent mentioned in S2 includes, but is not limited to, silicon tetrachloride, tin tetrachloride, trichlorosilane, dimethyl dichloride, γ-aminopropyltriethoxysilane, and γ-glycidoxypropyltrimethoxysilane, with the specific structures shown below:

[0022]

[0023] Further specified, the molar ratio of the coupling agent in S2 to the initiator in S1 is (0.1~10):1.

[0024] Furthermore, the molar ratio of the coupling agent in S2 to the initiator in S1 is (0.1–0.4):1.

[0025] Further specifying, the coupling reaction in S2 is carried out at a temperature of 10–150°C for a period of 3–24 hours.

[0026] Furthermore, the coupling reaction in S2 is limited to a temperature of 70°C and a time of 10 hours.

[0027] The second objective of this invention is to provide a multi-arm acrylate elastomer obtained by the above method.

[0028] Further specifying, the multi-arm acrylate elastomer is a two-arm acrylate elastomer, a three-arm acrylate elastomer, or a four-arm star-shaped acrylate elastomer.

[0029] Further specified, the number-average molecular weight of the multi-arm acrylate elastomer is 100,000 to 1,500,000 g / mol, and the molecular weight distribution (PDI) is 1.1 to 2.0.

[0030] Furthermore, the number-average molecular weight of the multi-arm acrylate elastomer is 800,000 to 1,400,000 g / mol, and the molecular weight distribution (PDI) is 1.5 to 1.7.

[0031] Further specified, the elongation at break of the multi-arm acrylate elastomer is 100-600%, and the tensile strength is 2-20 MPa.

[0032] Furthermore, the elongation at break of the multi-arm acrylate elastomer is 260-500%, and the tensile strength is 4-7.5 MPa.

[0033] Further specified, the syndiotactic regularity (rr) of the alkyl methacrylate blocks in the multi-arm acrylate elastomer is 70-80%.

[0034] Furthermore, the syndiotactic regularity (rr) of the alkyl methacrylate blocks in the multi-arm acrylate elastomer is 75-80%.

[0035] A third objective of this invention is to provide an application of the multi-arm acrylate elastomer obtained by the above method in the fields of pharmaceuticals, food packaging, and viscosity index improvers.

[0036] The significant advantages of this invention compared to existing technologies are:

[0037] (1) The multi-arm acrylate elastomer of this invention has a number-average molecular weight of 100,000-1,200,000 g / mol and a molecular weight distribution of 1.1-2.0. Compared with traditional preparation methods, the multi-arm acrylate elastomer has milder, simpler, and more effective reaction conditions. It can effectively achieve the coupling of acrylate diblock polymers by simply adding a coupling agent without the need for additional catalysts. The coupled polymer has excellent viscosity, environmental friendliness, and mechanical properties, and occupies an important position in the fields of medicine, children's toys, and food packaging.

[0038] (2) The initiation system of this application is well applicable to industrial systems. It adopts a milder reaction temperature polymerization system and the reaction conditions are simpler and easier to implement, which is conducive to realizing industrial production.

[0039] (3) The coupling system of the present invention can achieve more effective control of product coupling by changing the type of coupling agent, the amount of coupling agent added and the coupling temperature, while the product molecular chain is not damaged, and the product has better processing performance, mechanical properties, etc., and can be applied to food, medical, viscosity index improver, etc. Attached Figure Description

[0040] Figure 1 The multi-arm acrylate elastomer of Example 7 1 1H NMR spectrum (400MHz, CDCl3, 298K);

[0041] Figure 2 The multi-arm acrylate elastomer of Example 7 13 C10 NMR spectrum (100MHz, CDCl3, 298K);

[0042] Figure 3 The GPC spectrum of the multi-arm acrylate elastomer in Example 7 is shown. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0044] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0045] The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used in the following embodiments, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such a composition, step, method, article, or apparatus.

[0046] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1 to 5” is disclosed, the described range should be interpreted as including ranges “1 to 4”, “1 to 3”, “1 to 2”, “1 to 2 and 4 to 5”, “1 to 3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range. In this specification and claims, range definitions may be combined and / or interchanged, unless otherwise stated, these ranges include all subranges contained therein.

[0047] The indefinite articles “a” and “an” preceding an element or component of this invention do not impose any limitation on the quantity (i.e., number of times) of the element or component. Therefore, “an” or “a” should be interpreted as including one or at least one, and the singular form of an element or component also includes the plural form, unless the quantity clearly refers only to the singular form.

[0048] The coupling rate of the multi-arm acrylate elastomer described in the following examples is mainly characterized by the GPC peak shape.

[0049] Coupling rate analysis: In the GPC spectrum, the peak area of ​​the diblock acrylate polymer substrate before coupling is S1, and the peak area of ​​the polymer after coupling is S2. The coupling rate is calculated using the following formula:

[0050] Coupling rate (%) = S2 / (S1+S2) × 100%

[0051] Analysis of PMMA regularity in the multi-arm acrylate elastomers described in the following examples (in 13 In the C-NMR spectrum, the peaks at 44.5 ppm, 44.8 ppm, and 45.5 ppm all belong to the quaternary carbons of the methyl methacrylate block, and these three peaks represent the stereoregularity of rr, mr, and mm, respectively.

[0052] rr PMMA (%) = [I 44.5 / (I44.5+ I 44.8+ I 45.5 )]×100%.

[0053] Example 1

[0054] The preparation steps of the multi-arm acrylate elastomer in this embodiment are as follows:

[0055] Under an argon atmosphere, toluene (60 mL) solution, ethylene glycol dimethyl ether (2.5 mL), i-BuAl(BHT)2 (1.6 mmol, 8 equiv.) aluminum reagent, sec-butyllithium initiator (0.2 mmol, 1 equiv.), and methyl methacrylate (2.7 mL, 25 mmol, 125 equiv.) were added sequentially to a 500 mL reaction flask. After reacting for one hour, n-butyl acrylate (17.2 mL, 120 mmol, 600 equiv.) was added. The reaction system was then continued to react at -30 °C for 1 hour. After the polymerization reaction was completed, silicon tetrachloride coupling agent (5.7 μL, 0.05 mmol, 0.25 equiv.) was added at 70 °C. After coupling reaction at 70 °C for 10 hours, the mixture was quenched with cold methanol and washed three times. The mixture was then vacuum dried at 40 °C to constant weight to obtain a four-arm acrylate elastomer.

[0056] The calculated yield was >99%. The number-average molecular weight M of the coupled four-arm acrylate elastomer was characterized by GPC. n The concentration was 1052789 g / mol, and the molecular weight distribution (PDI) was 1.6; the calculated coupling rate was 85%. The interblock regularity (rr) of PMMA was 77%. Mechanical property tests showed that the elongation at break of the four-arm acrylate elastomer was 394%, and the tensile strength was 6.89 MPa.

[0057] Example 2

[0058] The preparation steps of the multi-arm acrylate elastomer in this embodiment are as follows:

[0059] Under an argon atmosphere, toluene (60 mL) solution, ethylene glycol dimethyl ether (2.5 mL), i-BuAl(BHT)2 (1.6 mmol, 8 equiv.) aluminum reagent, sec-butyllithium initiator (0.2 mmol, 1 equiv.), and methyl methacrylate (2.7 mL, 25 mmol, 125 equiv.) were added sequentially to a 500 mL reaction flask. After reacting for one hour, n-butyl acrylate (17.2 mL, 120 mmol, 600 equiv.) was added. The reaction system was then continued to react at -30 °C for 1 hour. After the polymerization reaction was completed, trichlorosilane coupling agent (7.0 μL, 0.07 mmol, 0.33 equiv.) was added at room temperature. The coupling reaction was carried out at 70 °C for 10 hours. The mixture was then quenched with cold methanol and washed three times. The mixture was then vacuum dried at 40 °C to constant weight to obtain a three-arm acrylate elastomer.

[0060] The calculated yield was >99%. The number-average molecular weight M of the coupled three-arm acrylate elastomer was characterized by GPC. n The concentration was 964,879 g / mol, and the molecular weight distribution (PDI) was 1.5; the calculated coupling rate was 92%. The interblock regularity (rr) of PMMA was 80%. Mechanical property tests showed that the elongation at break of the three-arm acrylate elastomer was 471%, and the tensile strength was 4.13 MPa.

[0061] Example 3

[0062] The preparation steps of the multi-arm acrylate elastomer in this embodiment are as follows:

[0063] Under an argon atmosphere, toluene (60 mL) solution, ethylene glycol dimethyl ether (2.5 mL), i-BuAl(BHT)2 (1.6 mmol, 8 equiv.) aluminum reagent, sec-butyllithium initiator (0.2 mmol, 1 equiv.), and methyl methacrylate (2.7 mL, 25 mmol, 125 equiv.) were added sequentially to a 500 mL reaction flask. After reacting for one hour, n-butyl acrylate (17.2 mL, 120 mmol, 600 equiv.) was added. The reaction system was then continued to react at -30 °C for 1 hour. After the polymerization reaction was completed, dimethyl dichlorosilane coupling agent (11.8 μL, 0.1 mmol, 0.5 equiv.) was added at room temperature. The coupling reaction was carried out at 70 °C for 10 hours. The mixture was then quenched with cold methanol and washed three times. The mixture was then vacuum dried at 40 °C to constant weight to obtain a two-arm acrylate elastomer.

[0064] The calculated yield was >99%. The number-average molecular weight (M2) of the coupled two-arm acrylate elastomer was characterized by GPC. nThe concentration was 843790 g / mol, and the molecular weight distribution (PDI) was 1.6; the calculated coupling rate was 95%. The interblock regularity (rr) of PMMA was 75%. Mechanical property tests showed that the elongation at break of the two-arm acrylate elastomer was 363%, and the tensile strength was 6.91 MPa.

[0065] Example 4

[0066] The preparation steps of the multi-arm acrylate elastomer in this embodiment are as follows:

[0067] Under an argon atmosphere, toluene (60 mL) solution, ethylene glycol dimethyl ether (2.5 mL), i-BuAl(BHT)2 (1.6 mmol, 8 equiv.) aluminum reagent, sec-butyllithium initiator (0.2 mmol, 1 equiv.), and methyl methacrylate (2.7 mL, 25 mmol, 125 equiv.) were added sequentially to a 500 mL reaction flask. After reacting for one hour, n-butyl acrylate (17.2 mL, 120 mmol, 600 equiv.) was added. The reaction system was then continued to react at -30 °C for 1 hour. After the polymerization reaction was completed, silicon tetrachloride coupling agent (2.3 μL, 0.02 mmol, 0.1 equiv.) was added at room temperature. After coupling reaction at 70 °C for 10 hours, the mixture was quenched with cold methanol and washed three times. The mixture was then vacuum dried at 40 °C to constant weight to obtain a four-arm acrylate elastomer.

[0068] The calculated yield was >99%. The number-average molecular weight M of the coupled four-arm acrylate elastomer was characterized by GPC. n The concentration was 1175730 g / mol, and the molecular weight distribution (PDI) was 1.5; the calculated coupling rate was 66%. The interblock regularity (rr) of PMMA was 76%. Mechanical property tests showed that the elongation at break of the four-arm acrylate elastomer was 383%, and the tensile strength was 5.34 MPa.

[0069] Example 5

[0070] The preparation steps of the multi-arm acrylate elastomer in this embodiment are as follows:

[0071] Under an argon atmosphere, toluene (60 mL) solution, ethylene glycol dimethyl ether (2.5 mL), i-BuAl(BHT)2 (1.6 mmol, 8 equiv.) aluminum reagent, sec-butyllithium initiator (0.2 mmol, 1 equiv.), and methyl methacrylate (2.7 mL, 25 mmol, 125 equiv.) were added sequentially to a 500 mL reaction flask. After reacting for one hour, n-butyl acrylate (17.2 mL, 120 mmol, 600 equiv.) was added. The reaction system was then continued to react at -30 °C for 1 hour. After the polymerization reaction was completed, silicon tetrachloride coupling agent (9.1 μL, 0.08 mmol, 0.4 equiv.) was added at room temperature. After coupling reaction at 70 °C for 10 hours, the mixture was quenched with cold methanol and washed three times. The mixture was then vacuum dried at 40 °C to constant weight to obtain a four-arm acrylate elastomer.

[0072] The calculated yield was >99%. The number-average molecular weight M of the coupled four-arm acrylate elastomer was characterized by GPC. n The concentration was 1092789 g / mol, and the molecular weight distribution (PDI) was 1.6; the calculated coupling rate was 78%. The interblock regularity (rr) of PMMA was 78%. Mechanical property tests showed that the elongation at break of the four-arm acrylate elastomer was 379%, and the tensile strength was 5.46 MPa.

[0073] Example 6

[0074] The preparation steps of the multi-arm acrylate elastomer in this embodiment are as follows:

[0075] Under an argon atmosphere, toluene (60 mL) solution, ethylene glycol dimethyl ether (2.5 mL), i-BuAl(BHT)₂ (1.6 mmol, 8 equiv.) aluminum reagent, sec-butyllithium initiator (0.2 mmol, 1 equiv.), and methyl methacrylate (2.7 mL, 25 mmol, 125 equiv.) were added sequentially to a 500 mL reaction flask. After reacting for one hour, n-butyl acrylate (17.2 mL, 120 mmol, 600 equiv.) was added. The reaction system was then kept at -30°C for 1 hour. After the polymerization reaction was completed, silicon tetrachloride coupling agent (2.9 μL, 0.025 mmol, 0.13 equiv.) was added for the first time at room temperature. After reacting for 2 hours, silicon tetrachloride coupling agent (2.9 μL, 0.025 mmol, 0.13 equiv.) was added for the second time. The coupling reaction was carried out at 70°C for 10 hours. The mixture was then quenched with cold methanol and washed three times. It was then vacuum dried at 40°C to constant weight to obtain a four-arm acrylate elastomer.

[0076] The calculated yield was >99%. The number-average molecular weight M of the coupled four-arm acrylate elastomer was characterized by GPC. nThe concentration was 1053278 g / mol, and the molecular weight distribution (PDI) was 1.6; the calculated coupling rate was 88%. The interblock regularity (rr) of PMMA was 76%. Mechanical property tests showed that the elongation at break of the four-arm acrylate elastomer was 390%, and the tensile strength was 5.13 MPa.

[0077] Example 7

[0078] The preparation steps of the multi-arm acrylate elastomer in this embodiment are as follows:

[0079] Under an argon atmosphere, toluene (60 mL) solution, ethylene glycol dimethyl ether (2.5 mL), i-BuAl(BHT)2 (1.6 mmol, 8 equiv.) aluminum reagent, sec-butyllithium initiator (0.2 mmol, 1 equiv.), and methyl methacrylate (2.7 mL, 25 mmol, 125 equiv.) were added sequentially to a 500 mL reaction flask. After reacting for one hour, n-butyl acrylate (17.2 mL, 120 mmol, 600 equiv.) was added. The reaction system was then continued to react at -30 °C for 1 hour. After the polymerization reaction was completed, silicon tetrachloride coupling agent (5.7 μL, 0.05 mmol, 0.25 equiv.) was added at room temperature. After coupling reaction at 25 °C for 10 hours, the mixture was quenched with cold methanol and washed three times. The mixture was then vacuum dried at 40 °C to constant weight to obtain a four-arm acrylate elastomer.

[0080] The calculated yield was >99%. The number-average molecular weight M of the coupled four-arm acrylate elastomer was characterized by GPC. n The concentration was 1381392 g / mol, and the molecular weight distribution (PDI) was 1.6; the calculated coupling rate was 33%. The interblock regularity (rr) of PMMA was 75%. Mechanical property tests showed that the elongation at break of the four-arm acrylate elastomer was 301%, and the tensile strength was 6.14 MPa.

[0081] Table 1. Molecular Weight Information

[0082] Peak <![CDATA[M p (g / mol)]]> <![CDATA[M n (g / mol)]]> <![CDATA[M w (g / mol)]]> <![CDATA[M z (g / mol)]]> <![CDATA[M z+1 (g / mol)]]> <![CDATA[M v (g / mol)]]> PDI Peak1 1186964 1381392 2398710 4269098 6068950 3984140 1.736 Peak2 142785 104475 169916 249104 316034 238325 1.626

[0083] Example 8

[0084] The preparation steps of the multi-arm acrylate elastomer in this embodiment are as follows:

[0085] Under an argon atmosphere, toluene (60 mL) solution, ethylene glycol dimethyl ether (2.5 mL), i-BuAl(BHT)2 (1.6 mmol, 8 equiv.) aluminum reagent, sec-butyllithium initiator (0.2 mmol, 1 equiv.), and methyl methacrylate (2.7 mL, 25 mmol, 125 equiv.) were added sequentially to a 500 mL reaction flask. After reacting for one hour, n-butyl acrylate (17.2 mL, 120 mmol, 600 equiv.) was added. The reaction system was then continued to react at -30 °C for 1 hour. After the polymerization reaction was completed, silicon tetrachloride coupling agent (5.7 μL, 0.05 mmol, 0.25 equiv.) was added at 50 °C. After coupling reaction at 50 °C for 10 hours, the mixture was quenched with cold methanol and washed three times. The mixture was then vacuum dried at 40 °C to constant weight to obtain a four-arm acrylate elastomer.

[0086] The calculated yield was >99%. The number-average molecular weight M of the coupled four-arm acrylate elastomer was characterized by GPC. n The concentration was 1195879 g / mol, and the molecular weight distribution (PDI) was 1.7; the calculated coupling rate was 61%. The interblock regularity (rr) of PMMA was 75%. Mechanical property tests showed that the elongation at break of the four-arm acrylate elastomer was 386%, and the tensile strength was 7.15 MPa.

[0087] Example 9

[0088] The preparation steps of the multi-arm acrylate elastomer in this embodiment are as follows:

[0089] Under an argon atmosphere, toluene (60 mL) solution, ethylene glycol dimethyl ether (2.5 mL), i-BuAl(BHT)2 (1.6 mmol, 8 equiv.) aluminum reagent, sec-butyllithium initiator (0.2 mmol, 1 equiv.), and methyl methacrylate (2.7 mL, 25 mmol, 125 equiv.) were added sequentially to a 500 mL reaction flask. After reacting for one hour, n-butyl acrylate (17.2 mL, 120 mmol, 600 equiv.) was added. The reaction system was then continued to react at -30 °C for 1 hour. After the polymerization reaction was completed and the system was brought back to room temperature, silicon tetrachloride coupling agent (5.7 μL, 0.05 mmol, 0.25 equiv.) was added. The coupling reaction was carried out at 70 °C for 10 hours. The mixture was then quenched with cold methanol and washed three times. The mixture was then vacuum dried at 40 °C to constant weight to obtain a four-arm acrylate elastomer.

[0090] The calculated yield was >99%. The number-average molecular weight M of the coupled four-arm acrylate elastomer was characterized by GPC. nThe concentration was 1,128,751 g / mol, and the molecular weight distribution (PDI) was 1.6. The calculated coupling rate was 88%. The interblock regularity (rr) of PMMA was 80%. Mechanical property tests showed that the elongation at break of the four-arm acrylate elastomer was 357%, and the tensile strength was 6.75 MPa.

[0091] Example 10

[0092] The preparation steps of the multi-arm acrylate elastomer in this embodiment are as follows:

[0093] Under an argon atmosphere, toluene (60 mL) solution, ethylene glycol dimethyl ether (2.5 mL), i-BuAl(BHT)2 (1.6 mmol, 8 equiv.) aluminum reagent, sec-butyllithium initiator (0.2 mmol, 1 equiv.), and methyl methacrylate (2.7 mL, 25 mmol, 125 equiv.) were added sequentially to a 500 mL reaction flask. After reacting for one hour, n-butyl acrylate (17.2 mL, 120 mmol, 600 equiv.) was added. The reaction system was then continued to react at -30 °C for 1 hour. After the polymerization reaction was completed and the system was brought back to room temperature, silicon tetrachloride coupling agent (5.7 μL, 0.05 mmol, 0.25 equiv.) was added. The coupling reaction was carried out at 70 °C for 5 hours. The mixture was then quenched with cold methanol and washed three times. The mixture was then vacuum dried at 40 °C to constant weight to obtain a four-arm acrylate elastomer.

[0094] The calculated yield was >99%. The number-average molecular weight M of the coupled four-arm acrylate elastomer was characterized by GPC. n The concentration was 1256437 g / mol, and the molecular weight distribution (PDI) was 1.5; the calculated coupling rate was 72%. The interblock regularity (rr) of PMMA was 75%. Mechanical property tests showed that the elongation at break of the four-arm acrylate elastomer was 272%, and the tensile strength was 5.13 MPa.

[0095] Example 11

[0096] The preparation steps of the multi-arm acrylate elastomer in this embodiment are as follows:

[0097] Under an argon atmosphere, toluene (60 mL) solution, ethylene glycol dimethyl ether (2.5 mL), i-BuAl(BHT)2 (1.6 mmol, 8 equiv.) aluminum reagent, sec-butyllithium initiator (0.2 mmol, 1 equiv.), and methyl methacrylate (2.7 mL, 25 mmol, 125 equiv.) were added sequentially to a 500 mL reaction flask. After reacting for one hour, n-butyl acrylate (17.2 mL, 120 mmol, 600 equiv.) was added. The reaction system was then continued to react at -30 °C for 1 hour. After the polymerization reaction was completed and the system was brought back to room temperature, silicon tetrachloride coupling agent (5.7 μL, 0.05 mmol, 0.25 equiv.) was added. The coupling reaction was carried out at 70 °C for 15 hours. The mixture was then quenched with cold methanol and washed three times. The mixture was then vacuum dried at 40 °C to constant weight to obtain a four-arm acrylate elastomer.

[0098] The calculated yield was >99%. The number-average molecular weight M of the coupled four-arm acrylate elastomer was characterized by GPC. n The concentration was 962,678 g / mol, and the molecular weight distribution (PDI) was 1.5. The calculated coupling rate was 85%. The interblock regularity (rr) of PMMA was 77%. Mechanical property tests showed that the elongation at break of the four-arm acrylate elastomer was 295%, and the tensile strength was 5.78 MPa.

[0099] The above description is merely a preferred embodiment of the present invention. These specific embodiments are different implementations based on the overall concept of the present invention, and the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a multi-arm acrylate elastomer, characterized in that, Follow these steps: S1: Under anhydrous and oxygen-free conditions, solvent, catalyst, initiator, alkyl methacrylate monomer, and alkyl acrylate monomer are added sequentially. After a certain polymerization time, a diblock polymer of alkyl methacrylate and alkyl acrylate with anionic initiation sites at the ends is generated, with the general structural formula AB; the catalyst is... i -BuAl(BHT)2, the initiator is sec-butyllithium, the polymerization reaction temperature is -30~25 ℃, and the reaction time is 2 h; S2: After the polymerization reaction is complete, a coupling agent is added to the reaction system, and the coupling reaction is carried out for a certain period of time to obtain a multi-arm acrylate elastomer. The coupling agent is one of the following structures: The coupling reaction was carried out at a temperature of 70 °C for a time of 10 h.

2. The method according to claim 1, characterized in that, The alkyl methacrylate in S1 is one or more of the following structures: ， Alkyl acrylates have one or more of the following structures: 。 3. The method according to claim 1, characterized in that, The solvent in S1 is one or a mixture of several of toluene, ethylbenzene, xylene, benzene, N,N'-dimethylformamide, dimethyl sulfoxide, ethylene glycol dimethyl ether, tetrahydrofuran, dioxane, and methyl tert-butyl ether.

4. The method according to claim 3, characterized in that, The solvent in S1 is a mixture of toluene and ethylene glycol dimethyl ether in a volume ratio of 30:

1.

5. The method according to claim 1, characterized in that, The mass ratio of the total mass of alkyl methacrylate monomers and alkyl acrylate monomers to the solvent in S1 is 1:(1~10), and the molar ratio of the total molar mass of alkyl methacrylate monomers and alkyl acrylate monomers to the catalyst and initiator is 2000:(1~500):(0.5~4).

6. The method according to claim 5, characterized in that, The mass ratio of the total mass of alkyl methacrylate monomers and alkyl acrylate monomers in S1 to the mass of the solvent is 1:(1-3), and the molar ratio of the total molar mass of alkyl methacrylate monomers and alkyl acrylate monomers to the molar mass of the catalyst and initiator is 725:8:

1.

7. The method according to claim 1, characterized in that, The molar ratio of the coupling agent in S2 to the initiator in S1 is (0.1~10):

1.

8. The method according to claim 7, characterized in that, The molar ratio of the coupling agent in S2 to the initiator in S1 is (0.1~0.4):

1.

9. The multi-arm acrylate elastomer obtained by the method according to any one of claims 1-8, characterized in that, It is a two-armed acrylate elastomer, a three-armed acrylate elastomer, or a four-armed star-shaped acrylate elastomer.

10. The multi-arm acrylate elastomer according to claim 9, characterized in that, Its M n The content of the polymethyl methacrylate elastomer is 100,000 to 1,500,000 g / mol, the PDI is 1.1 to 2.0, the elongation at break is 100 to 600%, the tensile strength is 2 to 20 MPa, and the rr of the alkyl methacrylate block in the multi-arm acrylate elastomer is 70 to 80%.

11. The multi-arm acrylate elastomer according to claim 10, characterized in that, Its M n The concentration is 800,000-1,400,000 g / mol, the PDI is 1.5-1.7, the elongation at break is 260-500%, the tensile strength is 4-7.5 MPa, and the rr of the alkyl methacrylate block in the multi-arm acrylate elastomer is 75-80%.

12. The application of the multi-arm acrylate elastomer obtained by the method of any one of claims 1-8 in the fields of pharmaceuticals, food packaging, and viscosity index improvers.

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