Preparation of high-molecular composite functional brominated grafting agents and brominated branched butyl rubber

Abstract

This invention discloses a polymeric composite functional brominated grafting agent and its preparation method. The polymeric composite functional brominated grafting agent is a linear isotactic block copolymer composed of methyl allyl phosphate diester, methacrylamide, and 3,5-dibromostyrene. This invention also discloses a method for preparing brominated branched butyl rubber. The wide-temperature-range, high-damping brominated branched butyl rubber preparation method of this invention features environmental friendliness, low emissions, minimal product quality fluctuations, readily available raw materials, low production costs, and ease of industrial production.

Description

Technical Field

[0001] This invention relates to a polymeric composite functional brominated grafting agent and the preparation of a wide-temperature-range, high-damping brominated branched butyl rubber. Background Technology

[0002] With the rapid development of modern science and technology, mechanical equipment in many fields such as high-speed rail, aerospace, naval vessels, mechanical engineering, automobiles, and electronics is trending towards high frequency and high speed. While bringing convenience to daily production and life, this has also generated a series of problems, such as high-frequency vibration and noise. These problems not only accelerate the fatigue damage of mechanical structural materials and shorten their service life, but vibration reduction and noise reduction have also become one of the most pressing issues to be addressed in today's society. Therefore, developing high-performance, high-efficiency damping materials and improving their application in damping and vibration reduction is crucial for improving the operating environment of machinery and for protecting human health and safety.

[0003] Brominated butyl rubber (BIIR) is produced by electrophilic substitution of bromine atoms into the molecular chain of butyl rubber (IIR) under the influence of molecular bromine. Compared to IIR, BIIR, in addition to possessing the same excellent airtightness, also exhibits good adhesion, fast vulcanization speed, good thermal stability, and corrosion resistance, enabling its use in extreme environments such as strong corrosion or high temperatures. Furthermore, the introduction of bromine atoms increases the polarity of the molecular chain, leading to increased relaxation resistance and greater internal friction, resulting in excellent damping performance. Therefore, it is one of the most widely used basic damping rubbers. Currently, in practical applications, damping functionality is often required within the temperature range of -50℃ to +50℃. However, the effective damping functional region (damping factor tanδ > 0.3) of brominated butyl rubber is currently concentrated mainly in the low-temperature range, with damping values ​​being relatively low above 15℃. This fails to adequately meet the requirements for wide-temperature-range damping materials. Therefore, expanding the effective damping functional region of butyl rubber above room temperature is one of the current research hotspots in rubber damping materials.

[0004] In the prior art, the preparation methods of wide temperature range, high damping rubber materials mainly include blending, copolymerization, interpenetrating polymer networks, and adding organic small molecule functional damping agents.

[0005] Literature such as CN112574333A, CN102775659B, CN 106749816A, CN113969031A, CN103113682A, CN103113682A, as well as Tao Gang et al. (Polymer Materials Science and Engineering, 2013, 29(11): 114~118) and Liao Mingyi et al. (Journal of Dalian Maritime University, 2008, 34(2): 83~86) have shown that blending, copolymerization, and interpenetrating polymer networks can broaden the effective damping temperature range of rubber and improve its damping performance to a certain extent. However, these methods still have certain limitations, which can lead to a decrease in the mechanical properties of modified materials, complex processes, difficult practical operation, large addition amounts, high costs, difficulty in removing organic solvents, and environmental pollution. Summary of the Invention

[0006] One objective of this invention is to provide an effective damping temperature range (tanδ≥0.3) that meets the requirements for use within the range of -70℃ to 78℃, with a maximum damping factor tanδ. max A method for preparing a wide-temperature-range, high-damping brominated branched butyl rubber with a damping range of ≥2.2. This invention first uses anionic polymerization to synthesize a macromolecular composite functional agent from methyl allyl phosphate diester and vinyl amide polar monomers; secondly, it synthesizes a polymeric composite functional brominated grafting agent from the macromolecular composite functional agent and 3,5-dibromostyrene; finally, it prepares a wide-temperature-range, high-damping brominated branched butyl rubber by cationic polymerization of the polymeric composite functional brominated grafting agent with isobutylene and isoprene. This method directly embeds functionalized groups and bromine atoms into the butyl rubber chain structure through anionic and cationic reactions, rather than the free radical substitution reactions used in existing technologies, to form an interpenetrating polymer network (IPN). This endows the brominated branched butyl rubber with an effective damping temperature range and high efficiency, stability, and durability of damping performance.

[0007] In this invention, "%" refers to mass percentage.

[0008] As one aspect of the present invention, a polymeric composite functional brominated grafting agent is disclosed, which is a linear isotactic block copolymer composed of methyl allyl phosphate diester, methacrylamide, and 3,5-dibromostyrene, and its general structural formula is shown in Formula I:

[0009]

[0010] Wherein: I is a small molecule isoprene segment; B is a small molecule 1,3-butadiene segment; R is a C1-C4 alkyl group; n and m are the number of repeating units: n≥1, m≥1. The polymeric composite functional brominated grafting agent has a number-average molecular weight (Mn) of 50,000-60,000, a molecular weight distribution (Mw / Mn) of 1.52-1.97, and a bromine content of 5.82%-6.34% by mass.

[0011] As another aspect of the present invention, a method for preparing the above-mentioned polymeric composite functional brominated grafting agent is provided, comprising:

[0012] Based on 100% of the total mass of the reactants methyl allyl phosphate diester and vinyl amides, 100% to 200% solvent, 60% to 70% methyl allyl phosphate diester, and 0.2% to 0.3% structure modifier were added sequentially to the polymerization reactor. After heating to 60 to 70°C, an initiator was added and the reaction was allowed to proceed for 50 to 70 minutes. Subsequently, 30% to 40% methacrylamide and 0.1% to 0.2% structure modifier were added to the polymerization reactor, and the reaction was allowed to proceed for 30 to 40 minutes. Finally, 1.0% to 3.0% 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was allowed to proceed for 20 to 30 minutes until no free monomers were present. After the reaction was completed, the product was washed and dried to obtain a macromolecular composite functional agent.

[0013] Based on 100% by mass of the reactant monomer 3,5-dibromostyrene, firstly, in a jacketed 15L stainless steel reactor, argon gas is purged 3-5 times. Then, 200%-300% solvent, 100% 3,5-dibromostyrene, and 0.4%-0.6% structure modifier are added sequentially to the polymerization reactor. After heating to 60-70℃, an initiator is added, and the reaction is allowed to proceed for 100-120 minutes. Next, 20%-30% macromolecular composite functional agent and 0.3%-0.5% structure modifier are added to the polymerization reactor, and the temperature is raised to 70-80℃, reacting for 50-60 minutes. Finally, 3.0%-4.0% isoprene is added to the polymerization reactor for end-capping, and the reaction is allowed to proceed for 20-30 minutes until no free monomers remain. The resulting solution is then wet-coagulated and dried to obtain a high-molecular-weight composite functional brominated grafting agent. Preferably, nitrogen gas is purged 3 to 5 times before adding reactants to the reactor.

[0014] As another aspect of the present invention, a method for preparing brominated branched butyl rubber is provided, comprising:

[0015] Add 100% to 200% of the mixed solvent (diluent / solvent V:V ratio of 70% to 30% to 70%) and 4% to 7% of the polymeric composite functional brominated grafting agent to the polymerization reactor, based on 100% of the mass of the reactant isobutylene. Stir and dissolve for 40 to 50 minutes until the grafting agent is completely dissolved. Then, cool to -80 to -70°C, and add 100% to 200% of the diluent, 100% of the isobutylene, and 4% to 6% of the isoprene in sequence. Stir and mix until the polymerization system temperature drops to -90 to -80°C. Then, mix and age 10% to 20% of the diluent and 0.2% to 0.4% of the co-initiator at -100 to -90°C for 40 to 50 minutes, and then add them together to the polymerization system. Stir and react for 3.0 to 4.0 hours. Finally, add 3% to 7% of the isoprene. After adding 5% terminator, the material is discharged, coagulated, washed, and dried to obtain brominated branched butyl rubber.

[0016] The methyl allyl phosphate diester of the present invention is one of methyl allyl phosphate, methyl allyl phosphate, methyl allyl phosphate, and methyl allyl phosphate, preferably methyl allyl phosphate.

[0017] The initiator described in this invention is a hydrocarbon-based monolithium compound, namely RLi, wherein R is a saturated aliphatic hydrocarbon group, alicyclic hydrocarbon group, aromatic group, or a complex group containing 1 to 20 carbon atoms. This hydrocarbon-based monolithium compound is selected from one of n-butyllithium, sec-butyllithium, methylbutyllithium, phenylbutyllithium, naphthenelithium, cyclohexyllithium, and dodecyllithium, preferably n-butyllithium. The amount of organolithium added is determined by the molecular weight of the designed polymer.

[0018] The structure modifier described in this invention is a polar organic compound that produces a solvation effect in the polymerization system, enabling it to adjust the reactivity ratio of styrene and isoprene, thus allowing them to copolymerize randomly. This type of polar organic compound is selected from one of diethylene glycol dimethyl ether (DGE), tetrahydrofuran (THF), diethyl ether, ethyl methyl ether, anisole, diphenyl ether, diethylene glycol dimethyl ether (DME), and triethylamine, preferably tetrahydrofuran (THF).

[0019] The diluent described in this invention is a haloalkane, wherein the halogen atom in the haloalkane can be chlorine, bromine, or fluorine; and the number of carbon atoms in the haloalkane is C1-C4. This haloalkane is selected from one of chloromethane, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloropropane, heptachloropropane, fluoromethane, difluoromethane, tetrafluoroethane, carbon hexafluoride, and fluorobutane, preferably chloromethane.

[0020] The co-initiator described in this invention is composed of alkyl aluminum halides and protic acids in different proportions. The alkyl aluminum halide is selected from at least one of diethylaluminum chloride, diisobutylaluminum chloride, dichloromethylaluminum, sesquiethylaluminum chloride, sesquiisobutylaluminum chloride, dichloro-n-propylaluminum, dichloroisopropylaluminum, dimethylaluminum chloride, and ethylaluminum chloride, preferably sesquiethylaluminum chloride. The protic acid is selected from one of HCl, HF, HBr, H2SO4, H2CO3, H3PO4, and HNO3, preferably HCl. The total amount of co-initiator added is 0.05% to 0.4%, and the molar ratio of protic acid to alkyl aluminum halide is 0.01:1 to 0.1:1.

[0021] The terminating agent described in this invention may be selected from one or more of methanol, ethanol, and butanol.

[0022] The polymerization reactions described in this invention are all carried out in an oxygen-free and anhydrous environment, preferably in an inert gas environment. Both the polymerization and dissolution processes are completed in a hydrocarbon solvent. The solvent described in this invention is a hydrocarbon solvent, including straight-chain alkanes, aromatics, and cycloalkanes. This hydrocarbon solvent is selected from one of pentane, hexane, octane, heptane, cyclohexane, benzene, toluene, xylene, and ethylbenzene, with cyclohexane being preferred.

[0023] The macromolecular composite functional agent prepared by this invention combines two monomers with different polarities, methyl allyl phosphate diester and methacrylamide, into a single macromolecular chain via anionic polymerization. It has the characteristics of high isotacticity, strong adsorption force and multiple active sites. It produces a significant "synergistic effect" when improving the effective damping temperature range of the material, greatly improving the effective damping temperature range of brominated branched butyl rubber. It can prepare an effective damping temperature range (tanδ≥0.3) that can meet the requirements for use in the range of -70℃ to 78℃.

[0024] The polymeric composite functional brominated grafting agent prepared in this invention is produced by cationic polymerization. It combines two functional reactive monomers, 3,5-dibromostyrene and a macromolecular composite functional agent, on a single macromolecular chain. The "synergistic effect" generated by phenyl and bromine atoms not only improves the damping performance of brominated branched butyl rubber, but also avoids the problem of butyl rubber's mechanical properties and air tightness decreasing due to the widening of molecular weight distribution caused by branching.

[0025] The wide-temperature-range, high-damping brominated branched butyl rubber prepared by this invention is produced through cationic polymerization. A polymeric composite functional brominated grafting agent is embedded into the butyl rubber molecular chain structure to form an interpenetrating polymer network (IPN). Utilizing the "group effect," "structural effect," and "narrow molecular weight distribution" characteristics of the polymeric composite functional brominated grafting agent, the effective damping temperature range of the brominated branched butyl rubber can be significantly broadened. Simultaneously, the problem of decreased damping performance due to the broadening of the effective damping temperature range is avoided. This invention can produce an effective damping temperature range (tanδ≥0.3) that meets the requirements for use in the range of -70℃ to 78℃, with a maximum damping factor tanδ. max ≥2.2, wide temperature range, high damping brominated branched butyl rubber.

[0026] The wide-temperature-range, high-damping brominated branched butyl rubber prepared by this invention is generated by addition polymerization of a polymeric composite functional brominated grafting agent, rather than by ionic substitution. It produces no volatile organic compounds (VOCs) or byproduct HBr, thus blocking the conditions for bromine structural isomerization and improving the effective damping temperature range and the stability and durability of the damping performance of the brominated branched butyl rubber.

[0027] The present invention provides a method for preparing wide-temperature-range, high-damping brominated branched butyl rubber, which features environmental protection and low emissions, minimal product quality fluctuations, readily available raw materials, low production costs, and ease of industrial production. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0029] (1) Source of raw materials:

[0030]

[0031] All other reagents are commercially available industrial products.

[0032] (2) Analysis and testing methods:

[0033] Molecular weight and its distribution were determined using a Waters 2414 gel permeation chromatography (GPC) system (USA). A polystyrene standard was used as the calibration curve. The mobile phase was tetrahydrofuran, the column temperature was 40℃, the sample concentration was 1 mg / mL, the injection volume was 50 µL, the elution time was 40 min, and the flow rate was 1 mL / min. -1 .

[0034] Bromine content determination: Weigh 10 mg of sample and use a Q600 TG / DTG thermogravimetric analyzer at a heating rate of 10℃ / min in a nitrogen atmosphere with a flow rate of 50 mL / min to perform thermal degradation of the sample. The first stage of thermal degradation involves the debromination of bromine-containing units in the sample to form HBr. The bromine content (X) in the sample is then inferred from the percentage of HBr removed, using the following formula:

[0035]

[0036] In the formula: Y—percentage content of the sample at 220℃; 79.904—relative atomic mass of bromine; 1.008—relative atomic mass of hydrogen.

[0037] Molecular weight determination: Molecular weight was determined using a Waters 2414 gel permeation chromatography (GPC) system (Waters, Inc., USA). A polystyrene standard was used as the calibration curve. The mobile phase was tetrahydrofuran, the column temperature was 40℃, the sample concentration was 1 mg / mL, the injection volume was 50 µL, the elution time was 40 min, and the flow rate was 1 mL·min⁻¹.

[0038] Air tightness determination: An automated air tightness tester was used to determine the air permeability number according to ISO 2782:1995. The test gas was N2, the test temperature was 23℃, and the test sample was an 8cm diameter circular sea sheet with a thickness of 1mm.

[0039] Dynamic mechanical analysis (DMA): Measurements were performed in tensile mode on a Netzsch 242C dynamic mechanical analyzer (Germany). Sample dimensions were 10 mm long, 6 mm wide, and 2 mm thick. The temperature range was -90℃ to 90℃, with a heating rate of 3℃ / min. Data were analyzed at a frequency of 10 Hz.

[0040] Tensile strength: The method specified in standard GB / T528-2009 shall be applied.

[0041] Example 1

[0042] (1) Preparation of polymeric composite functional brominated grafting agent:

[0043] Preparation of macromolecular composite functional agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged three times. Then, 1000g of cyclohexane, 600g of dimethyl methyl allyl phosphate, and 2.0g of THF were added sequentially to the polymerization reactor. After heating to 60℃, 5.5 mmol of n-butyllithium was added to start the reaction for 50 min. Then, 400g of methacrylamide and 2.0g of THF were added to the polymerization reactor, and the reaction was carried out for 30 min. Finally, 10g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was carried out for 20 min until no free monomers were present. After the reaction was completed, the product was washed and dried to obtain the macromolecular composite functional agent.

[0044] b. Preparation of high molecular weight composite functional brominated grafting agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged three times. Then, 2000g of cyclohexane, 1000g of 3,5-dibromostyrene, and 4.0g of THF were added to the polymerization reactor in sequence. After heating to 60℃, 25.6mmol of n-butyllithium was added to start the reaction for 100min. Next, 200g of macromolecular composite functional agent and 3.0g of THF were added to the polymerization reactor, and the temperature was raised to 70℃ for 50min. Finally, 30g of isoprene was added to the polymerization reactor for end-capping, and the reaction was continued for 20min until no free monomers were present. The solution was wet-coagulated and dried to obtain the high molecular weight composite functional brominated grafting agent (Mn is 51000, Mw / Mn is 1.52, and bromine content is 5.82%). The polymeric composite functional brominated grafting agent obtained in this embodiment, in the general formula I, I is a small molecule isoprene segment; B is a small molecule 1,3-butadiene segment; R is methyl (CH3); n and m are the number of repeating units: n≥1, m≥1.

[0045] (2) Preparation of wide-temperature-range, high-damping brominated branched butyl rubber: First, in a 4L stainless steel reactor with a jacket, nitrogen gas was purged three times. 150g of dichloromethane, 350g of cyclohexane, and 20g of polymeric composite functional brominated grafting agent were added to the polymerization reactor and stirred for 40 minutes until completely dissolved. Then, the temperature was lowered to -70℃, and 500g of monochloromethane, 500g of isobutylene, and 20g of isoprene were added sequentially. The mixture was stirred until the polymerization system temperature dropped to -80℃. Then, 50g of monochloromethane, 1.12g of sesquiethylaluminum chloride, and 0.002g of HCl were mixed and aged at -90℃ for 40 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 3.0 hours. Finally, 15g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the wide-temperature-range, high-damping brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0046] Example 2

[0047] (1) Preparation of polymeric composite functional brominated grafting agent:

[0048] Preparation of macromolecular composite functional agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged three times. Then, 1200g of cyclohexane, 620g of dimethyl methyl allyl phosphate, and 2.3g of THF were added sequentially to the polymerization reactor. After heating to 63℃, 5.9 mmol of n-butyllithium was added to start the reaction for 55 min. Then, 380g of methacrylamide and 1.8g of THF were added to the polymerization reactor, and the reaction was carried out for 33 min. Finally, 15g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was carried out for 23 min until no free monomers were present. After the reaction was completed, the product was washed and dried to obtain the macromolecular composite functional agent.

[0049] b. Preparation of high molecular weight composite functional brominated grafting agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged three times. Then, 2300g of cyclohexane, 1000g of 3,5-dibromostyrene, and 4.6g of THF were added to the polymerization reactor in sequence. After heating to 63℃, 26.3mmol of n-butyllithium was added to start the reaction for 105min. Next, 220g of macromolecular composite functional agent and 3.5g of THF were added to the polymerization reactor, and the temperature was raised to 72℃ for 53min. Finally, 33g of isoprene was added to the polymerization reactor for end-capping, and the reaction was continued for 22min until no free monomers were present. The solution was wet-coagulated and dried to obtain the high molecular weight composite functional brominated grafting agent (Mn is 53000, Mw / Mn is 1.64, and bromine content is 5.95%). The polymeric composite functional brominated grafting agent obtained in this embodiment, in the general formula I, I is a small molecule isoprene segment; B is a small molecule 1,3-butadiene segment; R is methyl (CH3); n and m are the number of repeating units: n≥1, m≥1.

[0050] (2) Preparation of wide-temperature-range, high-damping brominated branched butyl rubber: First, in a 4L stainless steel reactor with a jacket, nitrogen gas was purged three times. 200g of dichloromethane, 300g of cyclohexane, and 23g of a polymer composite functional brominated grafting agent were added to the polymerization reactor and stirred for 43 minutes until completely dissolved. Then, the temperature was lowered to -73℃, and 600g of monochloromethane, 500g of isobutylene, and 23g of isoprene were added sequentially. The mixture was stirred until the polymerization system temperature dropped to -82℃. Then, 70g of monochloromethane, 1.34g of sesquiethylaluminum chloride, and 0.006g of HCl were mixed and aged at -93℃ for 42 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 3.3 hours. Finally, 18g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the wide-temperature-range, high-damping brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0051] Example 3

[0052] (1) Preparation of polymeric composite functional brominated grafting agent:

[0053] Preparation of macromolecular composite functional agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged four times. Then, 1500g of cyclohexane, 640g of dimethyl methyl allyl phosphate, and 2.5g of THF were added sequentially to the polymerization reactor. After heating to 66℃, 6.3 mmol of n-butyllithium was added to start the reaction for 60 min. Then, 360g of methacrylamide and 1.5g of THF were added to the polymerization reactor, and the reaction was carried out for 36 min. Finally, 20g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was carried out for 25 min until no free monomers were present. After the reaction was completed, the product was washed and dried to obtain the macromolecular composite functional agent.

[0054] b. Preparation of the polymeric composite functional brominated grafting agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged three times. Then, 2500g of cyclohexane, 1000g of 3,5-dibromostyrene, and 5.0g of THF were added to the polymerization reactor in sequence. After heating to 66℃, 27.1mmol of n-butyllithium was added to start the reaction for 110min. Next, 260g of macromolecular composite functional agent and 4.0g of THF were added to the polymerization reactor, and the temperature was raised to 75℃ for 56min. Finally, 35g of isoprene was added to the polymerization reactor for end-capping, and the reaction was continued for 26min until no free monomers were present. The solution was then wet-coagulated and dried to obtain the polymeric composite functional brominated grafting agent (Mn = 55000, Mw / Mn = 1.75, bromine content = 6.15%). The polymeric composite functional brominated grafting agent obtained in this embodiment, in the general formula I, I is a small molecule isoprene segment; B is a small molecule 1,3-butadiene segment; R is methyl (CH3); n and m are the number of repeating units: n≥1, m≥1.

[0055] (2) Preparation of wide-temperature-range, high-damping brominated branched butyl rubber: First, in a 4L stainless steel reactor with a jacket, nitrogen gas was purged four times. 560g of dichloromethane, 240g of cyclohexane, and 26g of polymeric composite functional brominated grafting agent were added to the polymerization reactor and stirred for 45 minutes until completely dissolved. Then, the temperature was lowered to -76℃, and 700g of monochloromethane, 500g of isobutylene, and 26g of isoprene were added sequentially. The mixture was stirred until the polymerization system temperature dropped to -85℃. Then, 80g of monochloromethane, 1.67g of sesquiethylaluminum chloride, and 0.008g of HCl were mixed and aged at -93℃ for 45 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 3.5 hours. Finally, 20g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the wide-temperature-range, high-damping brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0056] Example 4

[0057] (1) Preparation of polymeric composite functional brominated grafting agent:

[0058] Preparation of macromolecular composite functional agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged five times. Then, 1700g of cyclohexane, 660g of dimethyl methyl allyl phosphate, and 2.8g of THF were added sequentially to the polymerization reactor. After heating to 68℃, 6.8 mmol of n-butyllithium was added to start the reaction for 65 min. Subsequently, 340g of methacrylamide and 1.3g of THF were added to the polymerization reactor, and the reaction was carried out for 38 min. Finally, 25g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was carried out for 27 min until no free monomers were present. After the reaction was completed, the product was washed and dried to obtain the macromolecular composite functional agent.

[0059] b. Preparation of the polymeric composite functional brominated grafting agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged five times. Then, 2700g of cyclohexane, 1000g of 3,5-dibromostyrene, and 5.6g of THF were added sequentially to the polymerization reactor. After heating to 68℃, 27.8mmol of n-butyllithium was added to initiate the reaction for 115min. Next, 280g of macromolecular composite functional agent and 4.5g of THF were added to the polymerization reactor, and the temperature was raised to 77℃ for 58min. Finally, 37g of isoprene was added to the polymerization reactor for end-capping, and the reaction was continued for 28min until no free monomers were present. The solution was then wet-coagulated and dried to obtain the polymeric composite functional brominated grafting agent (Mn = 57000, Mw / Mn = 1.86, bromine content = 6.23%). The polymeric composite functional brominated grafting agent obtained in this embodiment, in the general formula I, I is a small molecule isoprene segment; B is a small molecule 1,3-butadiene segment; R is methyl (CH3); n and m are the number of repeating units: n≥1, m≥1.

[0060] (2) Preparation of wide-temperature-range, high-damping brominated branched butyl rubber: First, in a 4L stainless steel reactor with a jacket, nitrogen gas was purged five times. Then, 500g of dichloromethane, 300g of cyclohexane, and 30g of polymeric composite functional brominated grafting agent were added to the polymerization reactor and stirred for 47 minutes until completely dissolved. Next, the temperature was lowered to -78℃, and then 800g of monochloromethane, 500g of isobutylene, and 28g of isoprene were added sequentially. The mixture was stirred until the polymerization system temperature dropped to -87℃. Then, 90g of monochloromethane, 1.73g of sesquiethylaluminum chloride, and 0.010g of HCl were mixed and aged at -93℃ for 47 minutes, and then added to the polymerization system. The mixture was stirred and reacted for 3.8 hours. Finally, 23g of methanol was added, and the mixture was discharged, coagulated, washed, and dried to obtain the wide-temperature-range, high-damping brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0061] Example 5

[0062] (1) Preparation of polymeric composite functional brominated grafting agent:

[0063] Preparation of macromolecular composite functional agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged five times. Then, 2000g of cyclohexane, 700g of dibutyl methyl allyl phosphate, and 3.0g of THF were added sequentially to the polymerization reactor. After heating to 70℃, 7.3 mmol of n-butyllithium was added to start the reaction for 70 min. Subsequently, 300g of methacrylamide and 1.0g of THF were added to the polymerization reactor, and the reaction was carried out for 40 min. Finally, 30g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was carried out for 30 min until no free monomers were present. After the reaction was completed, the product was washed and dried to obtain the macromolecular composite functional agent.

[0064] b. Preparation of the polymeric composite functional brominated grafting agent: First, in a 15L stainless steel reactor with a jacket, argon gas was purged five times. Then, 3000g of cyclohexane, 1000g of 3,5-dibromostyrene, and 6.0g of THF were added sequentially to the polymerization reactor. After heating to 70℃, 28.6mmol of n-butyllithium was added to initiate the reaction for 120min. Next, 300g of macromolecular composite functional agent and 5.0g of THF were added to the polymerization reactor, and the temperature was raised to 80℃ for 60min. Finally, 40g of isoprene was added to the polymerization reactor for end-capping, and the reaction was continued for 30min until no free monomers were present. The solution was then wet-coagulated and dried to obtain the polymeric composite functional brominated grafting agent (Mn = 59700, Mw / Mn = 1.97, bromine content = 6.4%). The polymeric composite functional brominated grafting agent obtained in this embodiment, in the general formula I, I is a small molecule isoprene segment; B is a small molecule 1,3-butadiene segment; R is butyl (C4H9); n and m are the number of repeating units: n≥1, m≥1.

[0065] (2) Preparation of wide-temperature-range, high-damping brominated branched butyl rubber: First, in a 4L stainless steel reactor with a jacket, nitrogen gas was purged 5 times. Then, 300g of dichloromethane, 700g of cyclohexane, and 35g of high-molecular composite functional brominated grafting agent were added to the polymerization reactor and stirred for 50min until completely dissolved. Then, when the temperature was lowered to -80℃, 1000g of monochloromethane, 500g of isobutylene, and 30g of isoprene were added in sequence and stirred until the temperature of the polymerization system dropped to -100℃. Then, 100g of monochloromethane, 1.85g of sesquiethylaluminum chloride, and 0.018g of HCl were mixed and aged at -100℃ for 50min. Then, they were added to the polymerization system and stirred for 4.0hr. Finally, 25g of ethanol was added, and the product was discharged, coagulated, washed, and dried to obtain the wide-temperature-range, high-damping brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0066] Comparative Example 1

[0067] (1) Preparation of polymeric composite functional brominated grafting agent:

[0068] Preparation of macromolecular composite functional agent: Other conditions are the same as in Example 1, except that methacrylamide is not added during the preparation of macromolecular composite functional agent. Specifically: First, in a 15L stainless steel reactor with a jacket, argon gas is purged three times. Then, 1000g of cyclohexane, 600g of dimethyl methyl allyl phosphate, and 2.0g of THF are added to the polymerization reactor in sequence. After heating to 60°C, 5.5 mmol of n-butyllithium is added to start the reaction for 50 min. Then, 10g of 1,3-butadiene is added to the polymerization reactor for end-capping, and the reaction is continued for 20 min until no free monomers are present. After the reaction is completed, the product is washed and dried to obtain macromolecular composite functional agent-1.

[0069] b. Preparation of the polymeric composite functional brominated grafting agent: Other conditions are the same as in Example 1, except that no macromolecular composite functional agent is added during the preparation of the polymeric composite functional brominated grafting agent. Instead, macromolecular composite functional agent-1 is added in an amount of 200g. Specifically: First, in a 15L stainless steel reactor with a jacket, argon gas is purged three times. Then, 2000g of cyclohexane, 1000g of 3,5-dibromostyrene, and 4.0g of THF are added to the polymerization reactor in sequence. After heating to 60°C, 25.6 mmol of n-butyllithium is added to start the reaction for 100min. Next, 200g of macromolecular composite functional agent-1 and 3.0g of THF are added to the polymerization reactor. The temperature is raised to 70°C and the reaction is carried out for 50min. Finally, 30g of isoprene is added to the polymerization reactor for end-capping. The reaction is carried out for 20min until no free monomers are present. The solution is then wet-coagulated and dried to obtain the polymeric composite functional brominated grafting agent-1. The polymeric composite functional brominated grafting agent obtained in this comparative example, in the general formula I, I is a small molecule isoprene segment; B is a small molecule 1,3-butadiene segment; R is methyl (CH3); n and m are the number of repeating units: n≥1, m≥1.

[0070] (2) Preparation of wide-temperature-range, high-damping brominated branched butyl rubber: Other conditions are the same as in Example 1, except that: no polymeric composite functional brominated grafting agent is added during the preparation of wide-temperature-range, high-damping brominated branched butyl rubber. Instead, polymeric composite functional brominated grafting agent-1 is added, with an addition amount of 20g. That is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged three times, and 150g of dichloromethane, 350g of cyclohexane, and 20g of polymeric composite functional brominated grafting agent-1 are added to the polymerization reactor. The mixture is stirred and dissolved for 40min until it is completely dissolved. Then, when the temperature is lowered to -70℃, 500g of monochloromethane, 500g of isobutylene, and 20g of isoprene are added in sequence. The mixture is stirred and mixed until the temperature of the polymerization system drops to -80℃. Then, 50g of monochloromethane, 1.12g of sesquiethylaluminum chloride, and HCl are added. 0.002g of the mixture was aged at -90℃ for 40 minutes and then added to the polymerization system. After stirring and reacting for 3.0 hours, 15g of methanol was added. The mixture was then discharged, coagulated, washed, and dried to obtain a wide-temperature-range, high-damping brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0071] Comparative Example 2

[0072] (1) Preparation of polymeric composite functional brominated grafting agent:

[0073] Preparation of macromolecular composite functional agent: Other conditions are the same as in Example 2, except that dimethyl methacrylate is not added during the preparation of macromolecular composite functional agent, but methyl methacrylate is added instead, with an addition amount of 620g. Specifically: First, in a 15L stainless steel reactor with a jacket, argon gas is purged three times. Then, 1200g of cyclohexane, 620g of methyl methacrylate, and 2.3g of THF are added to the polymerization reactor in sequence. After heating to 63°C, 5.9 mmol of n-butyllithium is added to start the reaction for 55min. Then, 380g of methacrylamide and 1.8g of THF are added to the polymerization reactor, and the reaction is carried out for 33min. Finally, 15g of 1,3-butadiene is added to the polymerization reactor for end-capping, and the reaction is carried out for 23min until no free monomers are present. After the reaction is completed, the product is washed and dried to obtain macromolecular composite functional agent-2.

[0074] b. Preparation of the polymeric composite functional brominated grafting agent: Other conditions are the same as in Example 2, except that no macromolecular composite functional agent is added during the preparation of the polymeric composite functional brominated grafting agent. Instead, macromolecular composite functional agent-2 is added in an amount of 220g. Specifically: First, in a 15L stainless steel reactor with a jacket, argon gas is purged three times. Then, 2300g of cyclohexane, 1000g of 3,5-dibromostyrene, and 4.6g of THF are added to the polymerization reactor in sequence. After heating to 63°C, 26.3 mmol of n-butyllithium is added to start the reaction for 105 min. Next, 220g of macromolecular composite functional agent-2 and 3.5g of THF are added to the polymerization reactor. The temperature is raised to 72°C and the reaction is carried out for 53 min. Finally, 33g of isoprene is added to the polymerization reactor for end-capping, and the reaction is carried out for 22 min until no free monomers are present. The solution is then wet-coagulated and dried to obtain the polymeric composite functional brominated grafting agent-2. The polymeric composite functional brominated grafting agent obtained in this comparative example, in the general formula I, I is a small molecule isoprene segment; B is a small molecule 1,3-butadiene segment; n and m are the number of repeating units: n≥1, m≥1.

[0075] (2) Preparation of wide-temperature-range, high-damping brominated branched butyl rubber: Other conditions are the same as in Example 2, except that: no polymeric composite functional brominated grafting agent is added during the preparation of wide-temperature-range, high-damping brominated branched butyl rubber. Instead, polymeric composite functional brominated grafting agent-2 is added, with an addition amount of 23g. That is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged three times, and 200g of dichloromethane, 300g of cyclohexane, and 23g of polymeric composite functional brominated grafting agent-2 are added to the polymerization reactor. The mixture is stirred and dissolved for 43min until it is completely dissolved. Then, when the temperature is lowered to -73℃, 600g of monochloromethane, 500g of isobutylene, and 23g of isoprene are added in sequence. The mixture is stirred and mixed until the temperature of the polymerization system drops to -82℃. Then, 70g of monochloromethane, 1.34g of sesquiethylaluminum chloride, and HCl are added. 0.006g of the mixture was aged at -93℃ for 42 minutes and then added to the polymerization system. After stirring and reacting for 3.3 hours, 18g of methanol was added. The mixture was then discharged, coagulated, washed, and dried to obtain a wide-temperature-range, high-damping brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0076] Comparative Example 3

[0077] (1) Preparation of polymeric composite functional brominated grafting agent:

[0078] Preparation of macromolecular composite functional agent: Other conditions are the same as in Example 3, except that the amount of dimethyl methyl allyl phosphate added in the preparation of macromolecular composite functional agent is 400g. That is: First, in a 15L stainless steel reactor with a jacket, argon gas is purged four times. Then, 1500g of cyclohexane, 400g of dimethyl methyl allyl phosphate, and 2.5g of THF are added to the polymerization reactor in sequence. After heating to 66℃, 6.3mmol of n-butyllithium is added to start the reaction for 60min. Then, 360g of methacrylamide and 1.5g of THF are added to the polymerization reactor and the reaction is carried out for 36min. Finally, 20g of 1,3-butadiene is added to the polymerization reactor for end-capping and the reaction is carried out for 25min until no free monomers are present. After the reaction is completed, the product is washed and dried to obtain macromolecular composite functional agent-3.

[0079] b. Preparation of the polymeric composite functional brominated grafting agent: Other conditions are the same as in Example 3, except that no macromolecular composite functional agent is added during the preparation of the polymeric composite functional brominated grafting agent. Instead, macromolecular composite functional agent-3 is added in an amount of 260g. Specifically: First, in a 15L stainless steel reactor with a jacket, argon gas is purged three times. Then, 2500g of cyclohexane, 1000g of 3,5-dibromostyrene, and 5.0g of THF are added to the polymerization reactor in sequence. After heating to 66°C, 27.1 mmol of n-butyllithium is added to start the reaction for 110 min. Next, 260g of macromolecular composite functional agent-3 and 4.0g of THF are added to the polymerization reactor. The temperature is raised to 75°C and the reaction is carried out for 56 min. Finally, 35g of isoprene is added to the polymerization reactor for end-capping, and the reaction is carried out for 26 min until no free monomers are present. The solution is then wet-coagulated and dried to obtain the polymeric composite functional brominated grafting agent. The polymeric composite functional brominated grafting agent obtained in this comparative example, in the general formula I, I is a small molecule isoprene segment; B is a small molecule 1,3-butadiene segment; R is methyl (CH3); n and m are the number of repeating units: n≥1, m≥1.

[0080] (2) Preparation of wide-temperature-range, high-damping brominated branched butyl rubber: Other conditions are the same as in Example 3, except that: no polymeric composite functional brominated grafting agent is added during the preparation of wide-temperature-range, high-damping brominated branched butyl rubber. Instead, polymeric composite functional brominated grafting agent-3 is added, with an addition amount of 26g. That is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged four times, and 560g of dichloromethane, 240g of cyclohexane, and 26g of polymeric composite functional brominated grafting agent-3 are added to the polymerization reactor. The mixture is stirred and dissolved for 45min until it is completely dissolved. Then, when the temperature is lowered to -76℃, 700g of monochloromethane, 500g of isobutylene, and 26g of isoprene are added in sequence. The mixture is stirred and mixed until the temperature of the polymerization system drops to -85℃. Then, 80g of monochloromethane, 1.67g of sesquiethylaluminum chloride, and HCl are added. 0.008g of the mixture was aged at -93℃ for 45 minutes and then added to the polymerization system. After stirring and reacting for 3.5 hours, 20g of methanol was added. The mixture was then discharged, coagulated, washed, and dried to obtain a wide-temperature-range, high-damping brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0081] Comparative Example 4

[0082] (1) Preparation of polymeric composite functional brominated grafting agent:

[0083] Preparation of macromolecular composite functional agent: Other conditions are the same as in Example 4, except that: instead of anionic polymerization, free radical polymerization is used in the preparation of macromolecular composite functional agent, and benzoyl peroxide (BPO) is added instead of n-butyllithium as the initiator. The amount added is 6.8 mmol. That is: first, in a 15L stainless steel reactor with a jacket, argon gas is purged 5 times, and 1700g of cyclohexane, 660g of dimethyl methyl allyl phosphate, and 2.8g of THF are added to the polymerization reactor in sequence. After heating to 68°C, 6.8 mmol of BPO is added to start the reaction for 65 min; then 340g of methacrylamide and 1.3g of THF are added to the polymerization reactor, and the reaction is carried out for 38 min; finally, 25g of 1,3-butadiene is added to the polymerization reactor for end-capping, and the reaction is carried out for 27 min until no free monomers are present. After the reaction is completed, the product is washed and dried to obtain macromolecular composite functional agent-4.

[0084] b. Preparation of the polymeric composite functional brominated grafting agent: Other conditions are the same as in Example 4, except that no macromolecular composite functional agent is added during the preparation of the polymeric composite functional brominated grafting agent. Instead, macromolecular composite functional agent-4 is added in an amount of 280g. Specifically: First, in a 15L stainless steel reactor with a jacket, argon gas is purged five times. Then, 2700g of cyclohexane, 1000g of 3,5-dibromostyrene, and 5.6g of THF are added to the polymerization reactor in sequence. After heating to 68°C, 27.8mmol of n-butyllithium is added to start the reaction for 115min. Next, 280g of macromolecular composite functional agent-4 and 4.5g of THF are added to the polymerization reactor. The temperature is raised to 77°C and the reaction is carried out for 58min. Finally, 37g of isoprene is added to the polymerization reactor for end-capping, and the reaction is carried out for 28min until no free monomers are present. The solution is then wet-coagulated and dried to obtain the polymeric composite functional brominated grafting agent-4. The polymeric composite functional brominated grafting agent obtained in this comparative example, in the general formula I, I is a small molecule isoprene segment; B is a small molecule 1,3-butadiene segment; R is methyl (CH3); n and m are the number of repeating units: n≥1, m≥1.

[0085] (2) Preparation of wide-temperature-range, high-damping brominated branched butyl rubber: Other conditions are the same as in Example 4, except that: no polymeric composite functional brominated grafting agent is added during the preparation of wide-temperature-range, high-damping brominated branched butyl rubber. Instead, polymeric composite functional brominated grafting agent-4 is added, with an addition amount of 30g. That is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged 5 times, and 500g of dichloromethane, 300g of cyclohexane, and 30g of polymeric composite functional brominated grafting agent-4 are added to the polymerization reactor. The mixture is stirred and dissolved for 47min until it is completely dissolved. Then, when the temperature is lowered to -78℃, 800g of monochloromethane, 500g of isobutylene, and 28g of isoprene are added in sequence. The mixture is stirred and mixed until the temperature of the polymerization system drops to -87℃. Then, 90g of monochloromethane, 1.73g of sesquiethylaluminum chloride, and HCl are added. 0.010g of the mixture was aged at -93℃ for 47 minutes and then added to the polymerization system. After stirring and reacting for 3.8 hours, 23g of methanol was added. The mixture was then discharged, coagulated, washed, and dried to obtain a wide-temperature-range, high-damping brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0086] Comparative Example 5

[0087] (1) Preparation of polymeric composite functional brominated grafting agent:

[0088] Preparation of macromolecular complex functional agents: Same as in Example 5.

[0089] b. Preparation of the polymeric composite functional brominated grafting agent: Other conditions are the same as in Example 5, except that 3,5-dibromostyrene is not added during the preparation of the polymeric composite functional brominated grafting agent. Instead, allyl bromide is added in an amount of 1000g. Specifically: First, in a 15L stainless steel reactor with a jacket, argon gas is purged five times. Then, 3000g of cyclohexane, 1000g of allyl bromide, and 6.0g of THF are added sequentially to the polymerization reactor. After heating to 70°C, 28.6 mmol of n-butyllithium is added to start the reaction for 120min. Next, 300g of macromolecular composite functional agent and 5.0g of THF are added to the polymerization reactor. The temperature is raised to 80°C and the reaction is carried out for 60min. Finally, 40g of isoprene is added to the polymerization reactor for end-capping. The reaction is carried out for 30min until no free monomers are present. The solution is then wet-coagulated and dried to obtain the polymeric composite functional brominated grafting agent-5. The polymeric composite functional brominated grafting agent obtained in this comparative example, in the general formula described in Formula I, I is a small molecule isoprene segment; B is a small molecule 1,3-butadiene segment; R is butyl (C4H9); n and m are the number of repeating units: n≥1, m≥1.

[0090] (2) Preparation of wide-temperature-range, high-damping brominated branched butyl rubber: Other conditions are the same as in Example 5, except that: no polymeric composite functional brominated grafting agent is added during the preparation of wide-temperature-range, high-damping brominated branched butyl rubber. Instead, polymeric composite functional brominated grafting agent-5 is added, with an addition amount of 35g. That is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged 5 times, and 300g of dichloromethane, 700g of cyclohexane, and 35g of polymeric composite functional brominated grafting agent-5 are added to the polymerization reactor. The mixture is stirred and dissolved for 50min until it is completely dissolved. Then, when the temperature is lowered to -80℃, 1000g of monochloromethane, 500g of isobutylene, and 30g of isoprene are added in sequence. The mixture is stirred and mixed until the temperature of the polymerization system drops to -100℃. Then, 100g of monochloromethane, 1.85g of sesquiethylaluminum chloride, and HCl are added. 0.018g of the mixture was aged at -100℃ for 50 min, then added to the polymerization system and stirred for 4.0 hr. Finally, 25g of ethanol was added, the mixture was discharged, coagulated, washed, and dried to obtain a wide-temperature-range, high-damping brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0091] Comparative Example 6

[0092] (1) Preparation of polymeric composite functional brominated grafting agent:

[0093] Preparation of macromolecular complex functional agents: Same as in Example 5.

[0094] b. Preparation of polymeric composite functional brominated grafting agent: Same as in Example 5.

[0095] (2) Preparation of wide-temperature-range, high-damping brominated branched butyl rubber: Other conditions are the same as in Example 5, except that the amount of polymer composite functional brominated grafting agent added during the preparation of wide-temperature-range, high-damping brominated branched butyl rubber is 15g, that is: first, in a 4L stainless steel reactor with a jacket, nitrogen gas is purged 5 times, and 300g of dichloromethane, 700g of cyclohexane, and 15g of polymer composite functional brominated grafting agent are added to the polymerization reactor, and stirred and dissolved for 50min until completely dissolved; then, when the temperature is lowered to -80℃, 1000g of monochloromethane, 500g of isobutylene, and 30g of isoprene are added in sequence, and stirred and mixed until the temperature of the polymerization system drops to -100℃, and then 100g of monochloromethane and 1.85g of sesquiethylaluminum chloride are added. 0.018 g of HCl and 0.018 g of ethanol were mixed and aged at -100℃ for 50 min, then added to the polymerization system and stirred for 4.0 h. Finally, 25 g of ethanol was added, the mixture was discharged, coagulated, washed, and dried to obtain a wide-temperature-range, high-damping brominated branched butyl rubber product. Sampling and analysis: Standard samples were prepared, and the test performance is shown in Table 1.

[0096] Table 1. Properties of wide-temperature-range, high-damping brominated branched butyl rubber

[0097]

Claims

1. A method for preparing a polymeric composite functional brominated grafting agent, characterized in that, include: Based on 100% of the total mass of the reactants methyl allyl phosphate diester and vinyl amides, 100% to 200% solvent, 60% to 70% methyl allyl phosphate diester, and 0.2% to 0.3% structure modifier are added sequentially to a polymerization reactor. The reactor is heated to 60 to 70°C, and then an initiator is added, reacting for 50 to 70 minutes. The initiator is RLi, where R is a saturated aliphatic hydrocarbon group, alicyclic hydrocarbon group, aromatic group, or a complex group containing 1 to 20 carbon atoms. Subsequently, 30% to 40% methacrylamide and 0.1% to 0.2% structure modifier are added to the polymerization reactor, reacting for 30 to 40 minutes. Finally, 1.0% to 3.0% 1,3-butadiene is added to the polymerization reactor for end-capping, reacting for 20 to 30 minutes until no free monomers remain. After the reaction is complete, the mixture is washed and dried to obtain a macromolecular composite functional agent. Based on 100% by mass of the reactant monomer 3,5-dibromostyrene, 200% to 300% solvent, 100% 3,5-dibromostyrene, and 0.4% to 0.6% structure modifier are added sequentially to the polymerization reactor. After heating to 60 to 70°C, an initiator is added and the reaction is allowed to proceed for 100 to 120 minutes. Next, 20% to 30% macromolecular composite functional agent and 0.3% to 0.5% structure modifier are added to the polymerization reactor, and the temperature is raised to 70 to 80°C, with the reaction proceeding for 50 to 60 minutes. Finally, 3.0% to 4.0% isoprene is added to the polymerization reactor for end-capping, and the reaction is allowed to proceed for 20 to 30 minutes until no free monomers are present. The resulting solution is then wet-coagulated and dried to obtain a high-molecular-weight composite functional brominated grafting agent.

2. The method according to claim 1, characterized in that, The initiator is selected from one of n-butyllithium, sec-butyllithium, methylbutyllithium, phenylbutyllithium, naphthalenelithium, cyclohexyllithium, and dodecyllithium.

3. The method according to claim 2, characterized in that, The initiator is n-butyllithium.

4. The method according to claim 1, characterized in that, The structure modifier is selected from one of diethylene glycol dimethyl ether, tetrahydrofuran, diethyl ether, ethyl methyl ether, anisole, diphenyl ether, ethylene glycol dimethyl ether, and triethylamine.

5. The method according to claim 4, characterized in that, The structure modifier is tetrahydrofuran.

6. The method according to claim 1, characterized in that, The methyl allyl phosphate diester is one of methyl allyl phosphate, methyl allyl phosphate, methyl allyl phosphate, methyl allyl phosphate, and methyl allyl phosphate.

7. The method according to claim 6, characterized in that, The methyl allyl phosphate diester is methyl allyl phosphate dimethyl ester.

8. The method according to claim 1, characterized in that, The polymeric composite functional brominated grafting agent has a number average molecular weight of 50,000 to 60,000, a molecular weight distribution of 1.52 to 1.97, and a bromine content of 5.82% to 6.34% by mass.

9. A polymeric composite functional brominated grafting agent prepared by the method of any one of claims 1-8.

10. A method for preparing brominated branched butyl rubber, characterized in that, include: Add 100% to 200% of a mixed solvent (of 70% to 30% by mass of the reactant isobutylene) to the polymerization reactor. The mixed solvent is a diluent / solvent mixture with a ratio of 70% to 30% and 30% to 70%. Add 4% to 7% of the polymeric composite functional brominated grafting agent as described in claim 9. Stir and dissolve for 40 to 50 minutes until the grafting agent is completely dissolved. Then, cool to -80 to -70°C, and add 100% to 200% of the diluent, 100% of isobutylene, and 4% to 6% of isoprene sequentially. Stir and mix until the polymerization system temperature drops to -90 to -80°C. Then, mix and age 10% to 20% of the diluent and 0.2% to 0.4% of the co-initiator at -100 to -90°C for 40 to 50 minutes, and then add them together to the polymerization system. Stir and react for 3.0 to 4.0 hours. Finally, add 3% to 7% of the diluent. After adding 5% terminator, the material is discharged, coagulated, washed, and dried to obtain brominated branched butyl rubber.

11. The method according to claim 10, characterized in that, The diluent is a haloalkane, wherein the halogen atom in the haloalkane is chlorine, bromine or fluorine; and the number of carbon atoms in the haloalkane is C1-C4.

12. The method according to claim 11, characterized in that, The haloalkane is selected from one of the following: chloromethane, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloropropane, heptachloropropane, fluoromethane, difluoromethane, tetrafluoroethane, carbon hexafluoride, and fluorobutane.

13. The method according to claim 12, characterized in that, The haloalkane is monofluoromethane.

14. The method according to claim 10, characterized in that, The co-initiator is composed of alkyl aluminum halide and protic acid.

15. The method according to claim 14, characterized in that, The alkyl aluminum halide is selected from at least one of diethylaluminum chloride, diisobutylaluminum chloride, dichloromethylaluminum, sesquiethylaluminum chloride, sesquiisobutylaluminum chloride, dichloro-n-propylaluminum, dichloroisopropylaluminum, dimethylaluminum chloride, and ethylaluminum chloride; the protic acid is selected from one of HCl, HF, HBr, H2SO4, H2CO3, H3PO4, and HNO3.

16. The method according to claim 15, characterized in that, The alkyl aluminum halide is sesquiethyl aluminum chloride, and the protic acid is HCl.

17. The method according to claim 14, characterized in that, The total amount of co-initiator added is 0.05% to 0.4%, and the molar ratio of protic acid to alkyl aluminum halide is 0.01:1 to 0.1:

1.

18. The method according to claim 10, characterized in that, The terminator is selected from one or more of methanol, ethanol, and butanol.

19. The method according to claim 10, characterized in that, The solvent is selected from one of pentane, hexane, octane, heptane, cyclohexane, benzene, toluene, xylene, and ethylbenzene.

20. The method according to claim 19, characterized in that, The solvent is cyclohexane.

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