Methacryl-terminated polyphenylene ether and method for preparing the same

Abstract

The present application relates to a kind of methyl methacryl-terminated polyphenyl ether and its preparation method, the preparation method includes the following steps: (1) aromatic phenolic monomer is prepared by homogeneous method prepolymer;(2) the prepolymer prepared in step (1) is mixed with redistribution monomer and redistribution catalyst, reaction, obtain terminal hydroxyl polyphenyl ether solution;(3) the terminal hydroxyl polyphenyl ether solution prepared in step (2), double bond-containing acyl chloride end-capping agent, nucleophilic catalyst and stabilizer are reacted in microchannel reactor, obtain the methyl methacryl-terminated polyphenyl ether.The preparation method provided by the present application simultaneously has the characteristics of narrow molecular weight distribution, high unsaturation and high whiteness for the terminal vinyl polyphenyl ether prepared by the preparation method.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a methacryloyl-terminated polyphenylene ether and its preparation method. Background Technology

[0002] In the field of electronic circuit boards, polyphenylene oxide (PPE) is suitable for the technical requirements of future high-frequency and high-speed communication due to its low dielectric constant and dielectric loss factor. It can be used in electronic circuit board substrate materials, signal receiver housings, and structural components for electronic signal transmitters or receivers.

[0003] Due to its inherent structural limitations, polyphenylene ether (PPE) suffers from high melt viscosity and poor compatibility with most other resins, necessitating functional modification. Functionalized PPE, with its high functional activity, can chemically react with many resins, increasing the compatibility of mixed resins and enhancing the crosslinking density of the cured material. This, in turn, improves the electrical and thermomechanical properties of the finished product.

[0004] Precipitation is a common process for preparing low molecular weight polyphenylene ether (PPE) using methanol or other poor solvents as reaction solvents. Because the generated PPE has low solubility in methanol, it gradually precipitates out. Methanol, as a polar solvent, can dissolve monomers but not polymers; the product precipitates directly during the reaction, interrupting chain growth and resulting in a wide molecular weight distribution. The precipitate may also encapsulate unreacted monomers or catalysts, requiring additional purification steps. Further dissolution is needed for subsequent PPE modification, making the process complex.

[0005] In the end-capping modification process of polyphenylene ether, acrylic compounds are often used as end-capping agents to prepare methacryloyl-terminated polyphenylene ether due to their high reactivity, but there are many technical difficulties in practical applications.

[0006] First, an imbalance in the amount of end-capping agent can lead to material performance degradation: if the amount of end-capping agent added is insufficient, its reaction with the terminal hydroxyl groups of polyphenylene ether will be incomplete, and the residual hydroxyl groups will easily undergo oxidative cross-linking during subsequent high-temperature processing, causing yellowing of the material, decreased thermal stability and reduced mechanical strength; while if the amount of end-capping agent added is too high, the excess end-capping agent and its by-products will remain in the system as coloring impurities, resulting in a yellowish or grayish color of the product, which will significantly reduce the appearance quality.

[0007] Secondly, uncontrollable side reactions of double bonds in the end-capping agent within the reaction system can easily lead to product quality problems. Under high temperature or free radical conditions, double bonds in the end-capping agent can undergo self-polymerization to form oligomers, or they can undergo cross-linking reactions with polyphenylene ether chains to form gelled products. This cross-linking structure not only deteriorates the solubility of polyphenylene ether and causes a sharp drop in melt flowability (or even complete loss of thermoplasticity), but also leads to a widening of the molecular weight distribution due to chain breakage or recombination, affecting the mechanical strength of the final product. At the same time, it seriously affects the material processing performance, such as causing blockages in the injection molding / extrusion process.

[0008] Therefore, there is a need to develop a method for preparing methacryloyl-terminated polyphenylene ether with a narrow molecular weight distribution, low content of colored impurities, and high whiteness, suitable for use as a substrate material for high-frequency electronic circuit boards. Summary of the Invention

[0009] To address the aforementioned technical problems, this invention provides a methacrylamide-terminated polyphenylene ether and its preparation method. The methacrylamide-terminated polyphenylene ether prepared by the method has the characteristics of controllable molecular weight, narrow molecular weight distribution, high unsaturation, low content of colored impurities, and high whiteness.

[0010] To achieve this objective, the present invention adopts the following technical solution:

[0011] In a first aspect, the present invention provides a method for preparing methacryloyl-terminated polyphenylene ether, the method comprising the following steps: (1) preparing a prepolymer from an aromatic phenolic monomer by a homogeneous method; (2) mixing the prepolymer obtained in step (1) with a redistribution monomer and a redistribution catalyst, reacting to obtain a hydroxyl-terminated polyphenylene ether solution; (3) reacting the hydroxyl-terminated polyphenylene ether solution obtained in step (2), a double-bonded acyl chloride end-capping agent, a nucleophilic catalyst and a stabilizer in a microchannel reactor to obtain the methacryloyl-terminated polyphenylene ether.

[0012] In this invention, hydroxyl-terminated polyphenylene ethers are prepared by homogeneous method and redistribution reaction. Then, without separating the product, they can be directly capped with a double-bonded acyl chloride capping agent under the action of a nucleophilic catalyst and a stabilizer to obtain vinyl-terminated polyphenylene ethers. In step (2), the redistribution method achieves molecular weight adjustment through the reaction of the prepolymer with the redistribution agent. The polymer chain undergoes a dynamic breaking-recombination process. After the long chain breaks into active fragments, it recombines to finally form oligomers with uniform molecular weight. This method can produce products with narrow molecular weight distribution and simple purification steps. In step (2), the addition of a redistribution catalyst can effectively prevent the redistribution reaction from slowing down, which helps to accelerate the redistribution reaction and shorten the reaction time. In step (3), the capping is carried out under the condition of adding a nucleophilic catalyst and a stabilizer. The stabilizer can effectively inhibit the redistribution reaction. Thermal oxidative degradation reduces the self-polymerization of double-bonded acyl chloride end-capping agents and the cross-linking between macromolecules produced, thus reducing product discoloration and gelation. Nucleophilic catalysts accelerate the end-capping reaction rate of double-bonded acyl chloride end-capping agents, ensuring sufficient reaction within a shorter residence time. The end-capping reaction is carried out in a microchannel reactor. Unlike conventional tubular and batch reactors, microchannel reactors offer higher heat exchange efficiency, allowing for better and timely removal of heat from reactions with significant exothermic effects, stabilizing the reaction temperature, preventing overheating, and significantly shortening the residence time of materials in the reactor, thereby improving production efficiency and reducing the impact of side reactions. The methacrylamide-terminated polyphenylene ether prepared by this method simultaneously exhibits narrow molecular weight distribution, high unsaturation, and high whiteness.

[0013] Preferably, the aromatic phenolic monomers include phenolic monomers and aromatic diphenol monomers.

[0014] Preferably, the phenolic monomers include 2,6-dimethylphenol and / or 2,3,6-trimethylphenol.

[0015] Preferably, the aromatic diphenol monomer includes tetramethylbisphenol F and / or tetramethylbisphenol A.

[0016] Preferably, the molar ratio of the phenolic monomer to the aromatic diphenol monomer is (32~37):1, for example, 33:1, 34:1, 35:1, or 36:1.

[0017] Preferably, the solvent used in the homogeneous method includes a good solvent.

[0018] Preferably, the good solvent includes any one or a combination of at least two of benzene, toluene, ethylbenzene, xylene, chloroform, dichloroethane, trichloroethane, or chlorobenzene, and more preferably toluene.

[0019] Preferably, the mass ratio of solvent to aromatic phenolic monomer used in the homogeneous method in step (1) is (2~5):1, for example 2.5:1, 3:1, 3.5:1, 4:1 or 4.5:1, and more preferably (3.5~4.5):1.

[0020] Preferably, the homogeneous preparation of the prepolymer in step (1) is carried out under the catalysis of a copper-based catalyst system.

[0021] Preferably, the copper-based catalyst system includes a copper-based catalyst, a ligand, and an additive.

[0022] Preferably, the copper-based catalyst comprises cuprous compounds and / or copper compounds.

[0023] Preferably, the cuprous compound includes any one or a combination of at least two of cuprous chloride, cuprous bromide, cuprous nitrate or cuprous sulfate, and more preferably cuprous chloride and / or cuprous bromide.

[0024] Preferably, the copper compound includes any one or a combination of at least two of copper chloride, copper bromide, copper nitrate, or copper sulfate, and more preferably copper chloride and / or copper bromide.

[0025] In this invention, the copper-based catalyst can be a copper salt obtained by reacting copper oxide and / or cuprous oxide with hydrogen halides.

[0026] Preferably, the molar ratio of the copper catalyst to the phenol monomer is (0.001~0.008):1, for example, 0.002:1, 0.003:1, 0.004:1, 0.005:1, 0.006:1 or 0.007:1, and more preferably (0.003~0.005):1.

[0027] Preferably, the ligand comprises an amine compound.

[0028] Preferably, the amine compound includes any one or a combination of at least two of n-propylamine, isopropylamine, n-butylamine, cyclohexylamine, di-n-propylamine, triethylamine, or tetramethylethylenediamine, and more preferably tetramethylethylenediamine.

[0029] Preferably, the molar ratio of the ligand to the copper catalyst is (0.5~5):1, such as 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1 or 4.5:1, and more preferably (1~2):1.

[0030] Preferably, the additive includes azodicarbonate.

[0031] In this invention, the auxiliary agent is azodicarbonate. Due to its electron-rich structure, after participating in the coordination structure of copper-based catalysts and ligands, it forms a hydrazine radical that is stabilized by copper coordination, thereby increasing the overall activity of the copper-based catalyst system.

[0032] Preferably, the azodicarbonate comprises any one or a combination of at least two of diethyl azodicarbonate (DEAD), diisopropyl azodicarbonate (DIAD), or tert-butyl azodicarbonate (DBAD); more preferably, it is diisopropyl azodicarbonate.

[0033] In this invention, the azodicarbonate is preferably diisopropyl azodicarbonate, which has the advantages of both high activity and low price.

[0034] Preferably, the molar ratio of the additive to the copper-based catalyst is (0.05~2):1, for example, 0.1:1, 0.3:1, 0.5:1, 0.7:1, 0.9:1, 1.1:1, 1.3:1, 1.5:1, 1.7:1 or 1.9:1, and more preferably (0.1~1):1.

[0035] Preferably, the homogeneous preparation of the prepolymer in step (1) is carried out under conditions of passing an oxygen-containing gas.

[0036] Preferably, the volume concentration of oxygen in the oxygen-containing gas is 21% to 100%, such as 30%, 40%, 50%, 60%, 70% or 80%, and more preferably 90% to 100%.

[0037] Preferably, the amount of oxygen introduced per hour during the homogeneous preparation of the prepolymer in step (1) is 0.6 to 3 times the amount of phenol monomer, for example, 0.9 times, 1.2 times, 1.5 times, 1.8 times, 2.1 times, 2.4 times or 2.7 times, and more preferably 1 to 1.4 times.

[0038] Preferably, the reaction temperature of the homogeneous method in step (1) is 30~70℃, such as 35℃, 40℃, 45℃, 50℃, 55℃, 60℃ or 65℃, and more preferably 45~55℃.

[0039] Preferably, the reaction time of the homogeneous method in step (1) is 45 to 90 min, such as 50 min, 60 min, 65 min, 70 min, 75 min, 80 min or 85 min, and more preferably 40 to 50 min.

[0040] Preferably, the homogeneous reaction in step (1) is carried out at a pressure of 0.8 to 1.25 bar (e.g., 0.85 bar, 0.9 bar, 0.95 bar, 1 bar, 1.05 bar, 1.15 bar or 1.2 bar, etc.), and more preferably at a pressure of 1 bar.

[0041] Preferably, the redistribution monomer is tetramethylhydroquinone.

[0042] Preferably, the molar ratio of the redistribution monomer to the aromatic diphenol monomer is (0.2~3):1, for example 0.5:1, 0.8:1, 1.1:1, 1.4:1, 1.7:1, 2.0:1, 2.3:1, 2.6:1 or 2.9:1, and more preferably (1.5~3):1;

[0043] Preferably, the redistribution catalyst in step (2) comprises dicumyl peroxide.

[0044] Preferably, the mass of the redistribution catalyst in step (2) is 0.5% to 5% of the mass of the redistribution monomer, such as 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% or 4.5%, and more preferably 1% to 1.5%.

[0045] Preferably, the reaction temperature in step (2) is 30~70℃, such as 35℃, 40℃, 45℃, 50℃, 55℃, 60℃ or 65℃, and more preferably 40~50℃.

[0046] Preferably, the reaction time in step (2) is 30 to 150 min, such as 50 min, 70 min, 90 min, 110 min or 130 min, and more preferably 50 to 90 min.

[0047] Preferably, step (2) further includes a step of removing water and part of the solvent after the reaction.

[0048] For example, the step of removing water and some solvent includes pumping the material in the batch reactor into a pressure distillation reactor, and distilling off all the water and some solvent from the material by pressure distillation.

[0049] Preferably, the solid content of the hydroxyl-terminated polyphenylene ether solution in step (2) is 30% to 50%, such as 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, or 48%, and more preferably 45% to 50%.

[0050] For example, steps (1) and (2) in this invention are carried out in a batch reactor, and the material temperature and reaction temperature are controlled by external circulation heat exchange.

[0051] Preferably, step (3) includes the following steps: mixing an acyl chloride end-capping agent containing double bonds, a nucleophilic catalyst, a stabilizer and a good solvent to form an end-capping agent solution, and passing the hydroxyl-terminated polyphenylene ether solution obtained in step (2) and the end-capping agent solution together into a microchannel reactor for reaction to obtain the methacryloxy-terminated polyphenylene ether.

[0052] Preferably, the double-bonded acyl chloride end-capping agent includes methacryloyl chloride.

[0053] Preferably, the nucleophilic catalyst comprises 4-dimethylaminopyridine (DMAP).

[0054] In this invention, the 4-dimethylaminopyridine, as a strong nucleophilic base, can form a highly active acylpyridinium intermediate with the acyl chloride end-capping agent, thereby accelerating the acyl chloride end-capping reaction rate.

[0055] Preferably, the mass of the nucleophilic catalyst is 0.5% to 5% of the mass of the acyl chloride end-capping agent containing double bonds, such as 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% or 4.5%, and more preferably 1.5% to 2%.

[0056] Preferably, the reaction in step (3) further includes adding alkali to carry out the reaction.

[0057] Preferably, the base includes any one or a combination of at least two of pyridine, diethylamine, or triethylamine, and more preferably triethylamine.

[0058] Preferably, the molar ratio of the base to the acyl chloride end-capping agent containing double bonds is (0.8~1.5):1, for example, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1 or 1.4:1, and more preferably (0.9~1.1):1.

[0059] Preferably, the stabilizer comprises triethyl phosphite.

[0060] Preferably, the mass of the stabilizer is 0.5% to 5% of the mass of the acyl chloride end-capping agent containing double bonds, such as 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% or 4.5%, and more preferably 1% to 2%.

[0061] Preferably, the mass ratio of the good solvent to the acyl chloride end-capping agent containing double bonds in the end-capping agent solution is (0.5~2):1, for example, 0.7:1, 0.9:1, 1.1:1, 1.3:1, 1.5:1, 1.7:1 or 1.9:1, etc.

[0062] Preferably, the molar amount of the double-bonded acyl chloride end-capping agent satisfies the following formula: M = (n × HV × m) / 56000, where M represents the molar amount of the vinyl end-capping agent, n is 0.95~1.1 (e.g., 0.97, 0.99, 1.01, 1.03, 1.05, 1.07 or 1.09, etc.), HV represents the hydroxyl value of the terminal hydroxyl polyphenylene ether, and m represents the mass of the terminal hydroxyl polyphenylene ether.

[0063] Preferably, n is 0.95 to 1.

[0064] Preferably, the aspect ratio of the microchannel reactor in step (3) is ≥100, such as 150, 200, 250, 300, 350, 400, 450, 500 or 550, and more preferably ≥400.

[0065] Preferably, the reaction temperature in the microchannel reactor in step (3) is 40~90℃, such as 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃ or 85℃, and more preferably 65~75℃.

[0066] Preferably, the residence time of the material in the microchannel reactor in step (3) is 1 to 5 min, such as 1.5 min, 2 min, 2.5 min, 3 min, 3.5 min, 4 min or 4.5 min, and more preferably 1 to 3 min.

[0067] Preferably, the reaction in step (3) further includes washing, precipitation and drying steps.

[0068] Preferably, the washing includes washing with an aqueous solution of hydrochloric acid and an aqueous solution of ethylenediaminetetraacetic acid (EDTA).

[0069] Preferably, the mass concentration of the hydrochloric acid aqueous solution is 0.5% to 3%, such as 0.8%, 1.1%, 1.4%, 1.7%, 2%, 2.3%, 2.6% or 2.9%, and more preferably 1% to 2%.

[0070] Preferably, the mass concentration of the ethylenediaminetetraacetic acid aqueous solution is 1% to 5%, such as 1.5%, 2%, 2.5%, 3%, 3.5%, 4% or 4.5%, and more preferably 2% to 3%.

[0071] Preferably, the mass of the hydrochloric acid aqueous solution is 20% to 40% of the total mass of the hydroxyl-terminated polyphenylene ether solution and the capping agent solution, for example, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, or 38%.

[0072] Preferably, the mass of the ethylenediaminetetraacetic acid aqueous solution is 20% to 40% of the total mass of the hydroxyl-terminated polyphenylene ether solution and the capping agent solution, for example, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, or 38%.

[0073] Preferably, the precipitation includes precipitation in a poor solvent.

[0074] Preferably, the precipitation includes the following steps: adding 1 to 1.5 times the mass of a poor solvent to initially precipitate methacryloyl-terminated polyphenylene ether, centrifuging, washing with 1 to 1.5 times the mass of a poor solvent to remove residual good solvent, and centrifuging again.

[0075] Preferably, the drying includes vacuum drying until the volatile content of the product is reduced to below 0.5 wt%, such as 0.05 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, or 0.4 wt%.

[0076] Preferably, the drying is performed using a vacuum drum dryer.

[0077] Preferably, the vacuum drying pressure is 0.3~0.7 atm, for example 0.35 atm, 0.4 atm, 0.45 atm, 0.5 atm, 0.55 atm, 0.6 atm or 0.65 atm, etc.

[0078] Preferably, the vacuum drying temperature is 50~70℃, such as 53℃, 56℃, 59℃, 62℃, 65℃ or 68℃.

[0079] In this invention, the washing process following the reaction in step (3) can remove the copper-based catalyst.

[0080] In a second aspect, the present invention provides a methacryloyl-terminated polyphenylene ether, which is prepared by the preparation method described in the first aspect.

[0081] Preferably, the degree of unsaturation of the methacrylamide-terminated polyphenylene ether is ≥1.7, such as 1.75, 1.8, 1.85, 1.9 or 1.95.

[0082] Preferably, the number average molecular weight of the methacrylamide-terminated polyphenylene ether is 1000~3500, such as 1100, 1300, 1500, 1700, 1900, 2100, 2300, 2500, 2700, 2900, 3100 or 3300.

[0083] Preferably, the molecular weight distribution of the methacrylamide-terminated polyphenylene ether is ≤2.25, such as 1.9, 1.95, 2, 2.05, 2.1, 2.15 or 2.2.

[0084] Preferably, the yellowness index of the methacrylamide-terminated polyphenylene ether is ≤10, for example, 1, 2, 3, 4, 5, 6, 7, 8 or 9.

[0085] Compared with the prior art, the present invention has at least the following beneficial effects:

[0086] This invention prepares hydroxyl-terminated polyphenylene ethers via a homogeneous method and a redistribution reaction. The product does not require separation and can be directly capped with a double-bonded acyl chloride capping agent under the action of a nucleophilic catalyst and stabilizer to obtain ethylene-terminated polyphenylene ethers. The preparation method is simple, and the resulting ethylene-terminated polyphenylene ethers exhibit controllable molecular weight, narrow molecular weight distribution, high unsaturation, low content of colored impurities, and high whiteness, making them suitable for use as substrate materials for high-frequency electronic circuit boards. Attached Figure Description

[0087] Figure 1 This is a schematic flowchart of the preparation method of methacryloyl-terminated polyphenylene ether provided in Example 1. Detailed Implementation

[0088] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0089] The microchannel reactor used in the following examples and comparative examples is the Corning AFR-G4 microchannel reactor, with a single module volume of 260 mL, a parallel connection of 7, and a total volume of 1.82 L.

[0090] Example 1

[0091] This embodiment provides a method for preparing hydroxyl-terminated polyphenylene ether solution and methacrylamide-terminated polyphenylene ether. A schematic flowchart of the preparation method is shown below. Figure 1 As shown, the preparation method includes the following steps:

[0092] (1) Add 200g methanol, 38g (0.004eq, 0.384mol, 99da) cuprous chloride, 66.8g (0.006eq, 0.576mol, 116da) tetramethylethylenediamine and 38.8g (0.002eq, 0.192mol, 202.2da) diisopropyl azodicarbonate to a beaker and stir for 15min to obtain a catalyst solution;

[0093] The catalyst solution was added to a 100L batch reactor, followed by 59.6 kg of toluene, 853 g (1 eq, 3 mol, 284.4 da) of tetramethylbisphenol A, and 11.7 kg (32 eq, 96 mol, 122 da) of 2,6-dimethylphenol. After stirring for 5 min, the materials dissolved. The external circulation heat exchanger of the batch reactor was turned on to control the temperature of the materials in the reactor to 45°C. The oxygen inlet was turned on, and oxygen was introduced into the batch reactor at a rate of 3.1 kg / h. The reaction was started from the beginning of oxygen introduction. During the polymerization reaction, the reactor was continuously stirred and the oxygen rate and the temperature in the reactor were kept stable. The reaction was stopped after 45 min. The oxygen supply and external circulation heating were turned off to prepare the prepolymer.

[0094] (2) Continue to add 1.49 kg (3 eq, 9 mol, 166.2 da) of tetramethylhydroquinone and dicumyl peroxide to the prepolymer obtained in step (1) in the batch reactor. The mass of dicumyl peroxide is 1.5% of the mass of tetramethylhydroquinone. Keep the reaction at 45°C for 60 min. After the reaction is completed, take a sample of the reaction solution and measure the viscosity of the reaction solution at 25°C to be 27.5 cp. Then pump the reaction solution in the batch reactor into a distillation column and distill off the water-containing toluene at 112°C to obtain a hydroxyl-terminated polyphenylene ether solution with a solid content of 50%. Pump the solution into a storage tank for later use.

[0095] (3) Mix 2.76 kg (26.4 mol, 104.5 da) of methacryloyl chloride, triethylamine, dimethylaminopyridine, triethyl phosphite and toluene by stirring and dissolving. The molar ratio of triethylamine to methacryloyl chloride is 1:1. The mass of dimethylaminopyridine is 2% of the mass of methacryloyl chloride. The mass of triethyl phosphite is 1.5% of the mass of methacryloyl chloride. The capping agent solution is obtained. The mass percentage of methacryloyl chloride in the capping agent solution is 25%.

[0096] (4) The hydroxyl-terminated polyphenylene ether solution obtained in step (2) and the end-capping agent solution obtained in step (3) are fed into a microchannel reactor using a metering pump for reaction. The rate of the hydroxyl-terminated polyphenylene ether solution is 620.5 g / min and the rate of the end-capping agent solution is 231.2 g / min. (The ratio of hydroxyl-terminated polyphenylene ether to methacryloyl chloride fed per unit time satisfies: M = (n × HV × m) / 56000, where M represents the molar amount of methacryloyl chloride, n is 1, HV represents the hydroxyl value of the hydroxyl-terminated polyphenylene ether, and m represents the mass of the hydroxyl-terminated polyphenylene ether). The microchannel reactor is set to a constant temperature of 70℃. The residence time of the material in the tubular reactor is 2 min. After 45 min, the metering pump is turned off and the residual material in the tubular reactor is discharged to obtain the product.

[0097] (5) Place the product obtained in step (4) into a washing vessel and cool it to 10°C. Then add 10 kg of hydrochloric acid aqueous solution (mass concentration of 1.5%) and mix. After stirring for 15 min, let it stand to separate into layers. Remove the aqueous phase. Then add 10 kg of ethylenediaminetetraacetic acid aqueous solution (mass concentration of 2.5wt%) and stir to dissolve for 30 min. Let it stand to separate into layers. Remove the aqueous phase. Pump the remaining polymer dispersion into a precipitation vessel. The temperature of the precipitation vessel is also maintained at 10°C through a heat exchanger. Add 30 kg of methanol to the precipitation vessel and keep stirring during this period to precipitate methacryloyl-terminated polyphenylene ether. After stirring for 30 min, let it stand for 15 min to precipitate the methacryloyl-terminated polyphenylene ether solid. After removing the supernatant using a pump, add 16 kg of methanol to the precipitation vessel again and stir vigorously for 30 min. The solid was allowed to precipitate completely by centrifugation, and then dried in a vacuum drum dryer at a pressure of 0.5 atm and a temperature of 60°C until the volatile content of the product was reduced to less than 0.5 wt%, yielding 16.3 kg of the methacryloyl-terminated polyphenylene ether.

[0098] Example 2

[0099] This embodiment provides a method for preparing hydroxyl-terminated polyphenylene ether solution and methacrylamide-terminated polyphenylene ether, the preparation method comprising the following steps:

[0100] (1) Add 200g methanol, 38g (0.004eq, 0.384mol, 99da) cuprous chloride, 66.8g (0.006eq, 0.576mol, 116da) tetramethylethylenediamine and 38.8g (0.002eq, 0.192mol, 202.2da) diisopropyl azodicarbonate to a beaker and stir for 15min to obtain a catalyst solution;

[0101] The catalyst solution was added to a 100L batch reactor, followed by 51.2 kg of toluene, 769 g (1 eq, 3 mol, 256.4 da) of tetramethylbisphenol F, and 14.3 kg (35.0 eq, 105.1 mol, 136 da) of 2,3,6-trimethylphenol. After stirring for 5 min, the materials dissolved. The external circulation heat exchanger of the batch reactor was turned on to control the temperature of the materials in the reactor to 45°C. The oxygen inlet was turned on, and oxygen was introduced into the batch reactor at a rate of 3.4 kg / h. The reaction was started from the beginning of oxygen introduction. During the polymerization reaction, the reactor was continuously stirred and the oxygen rate and the temperature in the reactor were kept stable. The reaction was stopped after 45 min. The oxygen supply and external circulation heating were turned off to prepare the prepolymer.

[0102] (2) Continue to add 100g (0.2eq, 0.6mol, 166.2da) of tetramethylhydroquinone and dicumyl peroxide to the prepolymer obtained in step (1) in the batch reactor. The mass of dicumyl peroxide is 1% of the mass of tetramethylhydroquinone. Keep the reaction at 45℃ for 60 min. Then pump the reaction liquid in the batch reactor into a distillation column and distill off the aqueous toluene at 112℃ to obtain a hydroxyl-terminated polyphenylene ether solution with a mass percentage concentration of 50% and a solid content of 50%.

[0103] (3) 828g (7.92mol, 104.5da) of methacryloyl chloride, triethylamine, dimethylaminopyridine, triethyl phosphite and toluene were stirred and dissolved evenly. The molar ratio of triethylamine to methacryloyl chloride was 1:1. The mass of dimethylaminopyridine was 2% of the mass of methacryloyl chloride and the mass of triethyl phosphite was 1.5% of the mass of methacryloyl chloride. The end-capping agent solution was obtained, and the mass percentage of methacryloyl chloride in the end-capping agent solution was 25%.

[0104] (4) The hydroxyl-terminated polyphenylene ether solution obtained in step (2) and the end-capping agent solution obtained in step (3) are fed into a microchannel reactor using a metering pump for reaction. The rate of the hydroxyl-terminated polyphenylene ether solution is 780.4 g / min and the rate of the end-capping agent solution is 79.8 g / min. (The ratio of hydroxyl-terminated polyphenylene ether to methacryloyl chloride fed per unit time satisfies: M=(n×HV×m) / 56000, where M represents the molar amount of methacryloyl chloride, n is 1, HV represents the hydroxyl value of the hydroxyl-terminated polyphenylene ether, and m represents the mass of the hydroxyl-terminated polyphenylene ether). The microchannel reactor is set to a constant temperature of 70℃. The residence time of the material in the tubular reactor is 2 min. After 45 min, the metering pump is turned off and the residual material in the tubular reactor is discharged to obtain the product.

[0105] (5) Place the product obtained in step (4) into a washing vessel and cool it to 10°C. Then add 10 kg of hydrochloric acid aqueous solution (mass concentration of 1.5%) and mix. After stirring for 15 min, let it stand to separate into layers. Remove the aqueous phase. Then add 10 kg of ethylenediaminetetraacetic acid aqueous solution (mass concentration of 2.5wt%) and stir to dissolve for 30 min. Let it stand to separate into layers. Remove the aqueous phase. Pump the remaining polymer dispersion into a precipitation vessel. The temperature of the precipitation vessel is also maintained at 10°C through a heat exchanger. Add 30 kg of methanol to the precipitation vessel and keep stirring during this period to precipitate methacryloyl-terminated polyphenylene ether. After stirring for 30 min, let it stand for 15 min to precipitate the methacryloyl-terminated polyphenylene ether solid. After removing the supernatant using a pump, add 16 kg of methanol to the precipitation vessel again and stir vigorously for 30 min. The solid was allowed to precipitate completely by centrifugation, and then dried in a vacuum drum dryer at a pressure of 0.5 atm and a temperature of 60°C until the volatile content of the product was reduced to less than 0.5 wt%, yielding 15.2 kg of the methacryloyl-terminated polyphenylene ether.

[0106] Example 3

[0107] This embodiment provides a method for preparing hydroxyl-terminated polyphenylene ether solution and methacrylamide-terminated polyphenylene ether, the preparation method comprising the following steps:

[0108] (1) Add 200g methanol, 38g (0.004eq, 0.384mol, 99da) cuprous chloride, 66.8g (0.006eq, 0.576mol, 116da) tetramethylethylenediamine and 38.8g (0.002eq, 0.192mol, 202.2da) diisopropyl azodicarbonate to a beaker and stir for 15min to obtain a catalyst solution;

[0109] The catalyst solution was added to a 100L batch reactor, followed by 51.2 kg of solvent toluene, 811 g (1 eq, 3 mol, 270.4 da) of 2,2',3,3',5,5'-hexamethyl-4,4'-dihydroxybiphenyl, 7.54 kg (18.5 eq, 55.4 mol, 136 da) of 2,3,6-trimethylphenol, and 6.76 kg (18.5 eq, 55.4 mol, 122 da) of xylenol. After stirring for 5 min, the materials dissolved. The external circulation heat exchanger of the batch reactor was turned on to control the temperature of the materials in the reactor to 45°C. The oxygen inlet was turned on, and oxygen was introduced into the batch reactor at a rate of 3.5 kg / h. The reaction was started from the beginning of oxygen introduction. During the polymerization reaction, the reactor was continuously stirred and the oxygen rate and the temperature in the reactor were kept stable. The reaction was stopped after 45 min. The oxygen supply and external circulation heating were turned off to prepare the prepolymer.

[0110] (2) Continue to add 100g (0.2eq, 0.6mol, 166.2da) of tetramethylhydroquinone and dicumyl peroxide to the prepolymer obtained in step (1) in the batch reactor. The mass of dicumyl peroxide is 1% of the mass of tetramethylhydroquinone. Keep the reaction at 45℃ for 60 min. Then pump the reaction liquid in the batch reactor into a distillation column and distill off the aqueous toluene at 112℃ to obtain a hydroxyl-terminated polyphenylene ether solution with a solid content of 50%.

[0111] (3) 828g (7.92mol, 104.5da) of methacryloyl chloride, triethylamine, dimethylaminopyridine, triethyl phosphite and toluene were stirred and dissolved evenly. The molar ratio of triethylamine to methacryloyl chloride was 1:1. The mass of dimethylaminopyridine was 2% of the mass of methacryloyl chloride and the mass of triethyl phosphite was 1.5% of the mass of methacryloyl chloride. The end-capping agent solution was obtained, and the mass percentage of methacryloyl chloride in the end-capping agent solution was 25%.

[0112] (4) The hydroxyl-terminated polyphenylene ether solution obtained in step (2) and the end-capping agent solution obtained in step (3) are fed into a microchannel reactor using a metering pump for reaction. The rate of the hydroxyl-terminated polyphenylene ether solution is 780.4 g / min and the rate of the end-capping agent solution is 83.0 g / min. (The ratio of hydroxyl-terminated polyphenylene ether to methacryloyl chloride fed per unit time satisfies: M=(n×HV×m) / 56000, where M represents the molar amount of methacryloyl chloride, n is 1, HV represents the hydroxyl value of the hydroxyl-terminated polyphenylene ether, and m represents the mass of the hydroxyl-terminated polyphenylene ether). The microchannel reactor is set to a constant temperature of 70℃. The residence time of the material in the tubular reactor is 2 min. After 45 min, the metering pump is turned off and the residual material in the tubular reactor is discharged to obtain the product.

[0113] (5) Place the product obtained in step (4) into a washing vessel and cool it to 10°C. Then add 10 kg of hydrochloric acid aqueous solution (mass concentration of 1.5%) and mix. After stirring for 15 min, let it stand to separate into layers. Remove the aqueous phase. Then add 10 kg of ethylenediaminetetraacetic acid aqueous solution (mass concentration of 2.5wt%) and stir to dissolve for 30 min. Let it stand to separate into layers. Remove the aqueous phase. Pump the remaining polymer dispersion into a precipitation vessel. The temperature of the precipitation vessel is also maintained at 10°C through a heat exchanger. Add 30 kg of methanol to the precipitation vessel and keep stirring during this period to precipitate methacryloyl-terminated polyphenylene ether. After stirring for 30 min, let it stand for 15 min to precipitate the methacryloyl-terminated polyphenylene ether solid. After removing the supernatant using a pump, add 16 kg of methanol to the precipitation vessel again and stir vigorously for 30 min. The solid was allowed to precipitate completely by centrifugation, and then dried in a vacuum drum dryer at a pressure of 0.5 atm and a temperature of 60°C until the volatile content of the product was reduced to less than 0.5 wt%, yielding 15.4 kg of the methacryloyl-terminated polyphenylene ether.

[0114] Example 4

[0115] This embodiment provides a method for preparing a hydroxyl-terminated polyphenylene ether solution and a methacryloyl-terminated polyphenylene ether. The difference between this method and Example 1 is that in step (4), the rate of the hydroxyl-terminated polyphenylene ether solution is 620.5 g / min and the rate of the end-capping agent solution is 255.5 g / min (the ratio of hydroxyl-terminated polyphenylene ether to methacryloyl chloride introduced per unit time satisfies: M = (n × HV × m) / 56000, where M represents the molar amount of methacryloyl chloride, n is 1.1, HV represents the hydroxyl value of the hydroxyl-terminated polyphenylene ether, and m represents the mass of the hydroxyl-terminated polyphenylene ether).

[0116] Other conditions are the same as in Example 1.

[0117] Example 5

[0118] This embodiment provides a method for preparing a hydroxyl-terminated polyphenylene ether solution and a methacryloyl-terminated polyphenylene ether. The difference between this method and Example 1 is that in step (4), the rate of the hydroxyl-terminated polyphenylene ether solution is 620.5 g / min and the rate of the end-capping agent solution is 220.2 g / min (the ratio of hydroxyl-terminated polyphenylene ether to methacryloyl chloride introduced per unit time satisfies: M = (n × HV × m) / 56000, where M represents the molar amount of methacryloyl chloride, n is 0.95, HV represents the hydroxyl value of the hydroxyl-terminated polyphenylene ether, and m represents the mass of the hydroxyl-terminated polyphenylene ether).

[0119] Other conditions are the same as in Example 1.

[0120] Example 6

[0121] This embodiment provides a method for preparing a hydroxyl-terminated polyphenylene ether solution and a methacryloyl-terminated polyphenylene ether. The difference between this method and Example 1 is that in step (4), the rate of the hydroxyl-terminated polyphenylene ether solution is 1.26 kg / min, and the rate of the capping agent solution is 460.8 g / min (the ratio of hydroxyl-terminated polyphenylene ether to methacryloyl chloride introduced per unit time satisfies: M = (n × HV × m) / 56000, where M represents the molar amount of methacryloyl chloride, n is 1, HV represents the hydroxyl value of the hydroxyl-terminated polyphenylene ether, and m represents the mass of the hydroxyl-terminated polyphenylene ether).

[0122] The microchannel reactor was set to a constant temperature of 90°C. The residence time of the material in the tubular reactor was 1 min. After 23 min, the metering pump was turned off and the residual material in the tubular reactor was discharged.

[0123] Other conditions are the same as in Example 1.

[0124] Example 7

[0125] This embodiment provides a method for preparing a hydroxyl-terminated polyphenylene ether solution and a methacryloyl-terminated polyphenylene ether. The difference between this method and Example 1 is that in step (4), the rate of the hydroxyl-terminated polyphenylene ether solution is 252 g / min, and the rate of the end-capping agent solution is 89.5 g / min (the ratio of hydroxyl-terminated polyphenylene ether to methacryloyl chloride introduced per unit time satisfies: M = (n × HV × m) / 56000, where M represents the molar amount of methacryloyl chloride, n is 1, HV represents the hydroxyl value of the hydroxyl-terminated polyphenylene ether, and m represents the mass of the hydroxyl-terminated polyphenylene ether).

[0126] The microchannel reactor was set to a constant temperature of 40°C. The residence time of the material in the tubular reactor was 5 min. After 117 min, the metering pump was turned off and the residual material in the tubular reactor was discharged.

[0127] Other conditions are the same as in Example 1.

[0128] Comparative Example 1

[0129] This comparative example provides a method for preparing a hydroxyl-terminated polyphenylene ether solution and a methacryloyl-terminated polyphenylene ether. The difference between this method and Example 1 is that step (2) is not included. The reaction in step (1) is continued for 17 min, the oxygen gas path is turned off, and the reaction is heated with external circulation. The reaction solution is sampled and the viscosity of the reaction solution at 25°C is tested to be 27.5 cp. Then, the reaction solution in the batch reactor is pumped into a distillation column, and the aqueous toluene is distilled off at 112°C to obtain a hydroxyl-terminated polyphenylene ether solution with a solid content of 50%.

[0130] In step (4), the rate of the hydroxyl-terminated polyphenylene ether solution is 169 g / min and the rate of the capping agent solution is 682.7 g / min (the ratio of hydroxyl-terminated polyphenylene ether and methacryloyl chloride introduced per unit time satisfies: M=(n×HV×m) / 56000, where M represents the molar amount of methacryloyl chloride, n is 1, HV represents the hydroxyl value of the hydroxyl-terminated polyphenylene ether, and m represents the mass of the hydroxyl-terminated polyphenylene ether).

[0131] Other conditions are the same as in Example 1.

[0132] Comparative Example 2

[0133] This comparative example provides a method for preparing a hydroxyl-terminated polyphenylene ether solution and a methacryloyl-terminated polyphenylene ether. The difference between this method and Example 1 is that dicumyl peroxide is not added in step (2).

[0134] In step (4), the rate of the hydroxyl-terminated polyphenylene ether solution is 175 g / min and the rate of the capping agent solution is 676.7 g / min (the ratio of hydroxyl-terminated polyphenylene ether and methacryloyl chloride introduced per unit time satisfies: M=(n×HV×m) / 56000, where M represents the molar amount of methacryloyl chloride, n is 1, HV represents the hydroxyl value of the hydroxyl-terminated polyphenylene ether, and m represents the mass of the hydroxyl-terminated polyphenylene ether).

[0135] Other conditions are the same as in Example 1.

[0136] Comparative Example 3

[0137] This comparative example provides a method for preparing a hydroxyl-terminated polyphenylene ether solution and a methacryloyl-terminated polyphenylene ether. The difference between this method and Example 1 is that dimethylaminopyridine is not added in step (3), while the other conditions are the same as in Example 1.

[0138] Comparative Example 4

[0139] This comparative example provides a method for preparing a hydroxyl-terminated polyphenylene ether solution and a methacryloyl-terminated polyphenylene ether. The difference between this method and Example 1 is that triethyl phosphite is not added in step (3), while the other conditions are the same as in Example 1.

[0140] Comparative Example 5

[0141] This comparative example provides a method for preparing a hydroxyl-terminated polyphenylene ether solution and a methacryloyl-terminated polyphenylene ether. The difference between this method and Example 1 is that step (4) is adjusted as follows: the hydroxyl-terminated polyphenylene ether solution obtained in step (2) is placed in a batch reactor using a metering pump, the heating is turned on to raise the temperature of the material in the batch reactor to 70°C, and the end-capping agent solution obtained in step (3) is added to the batch reactor at a rate of 434 g / min. The ratio of hydroxyl-terminated polyphenylene ether in the added hydroxyl-terminated polyphenylene ether solution to methacryloyl chloride in the end-capping agent solution satisfies the following: M = (n × HV × m) / 56000, where M represents the molar amount of methacryloyl chloride, n is 1, HV represents the hydroxyl value of the hydroxyl-terminated polyphenylene ether, and m represents the mass of the hydroxyl-terminated polyphenylene ether. The temperature in the batch reactor is kept stable during the addition. After the addition is completed, the reaction is continued for 5 min to obtain the product. Other conditions are the same as in Example 1.

[0142] The hydroxyl-terminated polyphenylene ether solutions and methacrylamide-terminated polyphenylene ethers provided in Examples 1 to 7 and Comparative Examples 1 to 5 were subjected to the following performance tests.

[0143] (1) Take 50g of hydroxyl-terminated polyphenylene ether solution and add it to 100g of methanol. Stir to precipitate the solid and filter it out. Wash the solid three times with methanol and dry it to obtain hydroxyl-terminated polyphenylene ether. Then take a sample for the following tests:

[0144] The number-average molecular weight (Mn) and molecular weight distribution (D) of a sample are determined by gel permeation chromatography in accordance with GB / T 27843-2011.

[0145] Hydroxyl value (HV) and functionality are determined using chemical titration (acylation reaction) in accordance with standard ASTM D4274.

[0146] The test results are shown in Table 1 below.

[0147] (2) The following tests were performed on methacryloyl-terminated polyphenylene ether:

[0148] The number-average molecular weight and molecular weight distribution of the samples were determined by gel permeation chromatography in accordance with GB / T 27843-2011.

[0149] The degree of unsaturation of methacryloyl-terminated polyphenylene ether samples was determined by iodometric titration according to GB / T 34247.1-2017.

[0150] The yellowness index (YI) of methacrylamide-terminated polyphenylene ether samples was determined using a spectrophotometer in accordance with standard ASTM D1925.

[0151] The test results are shown in Table 2 below.

[0152] Table 1

[0153]

[0154] Table 2

[0155]

[0156] The test results show that the vinyl-terminated polyphenylene ethers prepared by the methods provided in Examples 1 to 7 have a molecular weight distribution ≤2.21, an unsaturation degree ≥1.70, and a yellowness index ≤10, exhibiting characteristics of narrow molecular weight distribution, high unsaturation degree, and high whiteness.

[0157] Compared with Example 1, if the amount of double-bonded acyl chloride end-capping agent is too high (Example 4), the unsaturation of the prepared vinyl-terminated polyphenylene ether is not significantly improved, indicating that the double-bonded acyl chloride end-capping agent is excessive, and the yellowness index increases slightly; if the amount of double-bonded acyl chloride end-capping agent is too low (Example 5), the unsaturation of the prepared vinyl-terminated polyphenylene ether decreases.

[0158] Compared with Example 1, if step (4) increases the temperature and shortens the residence time (Example 6) to obtain a similar degree of unsaturation, the yellowness of the prepared vinyl-terminated polyphenylene ether increases; if step (4) decreases the temperature and increases the residence time (Example 7) to obtain a similar degree of unsaturation, the yellowness of the prepared vinyl-terminated polyphenylene ether increases slightly. It can be seen that excessively high temperature or excessively long residence time of materials in the reactor will affect the product quality.

[0159] Compared with Example 1, if no redistribution monomer and redistribution catalyst are added during the preparation of hydroxyl-terminated polyphenylene ether for redistribution reaction, and the reaction time of step (1) is shortened to obtain a reaction solution of the same viscosity (Comparative Example 1), the prepared hydroxyl-terminated polyphenylene ether has a wide molecular weight distribution and low hydroxyl value. Correspondingly, the prepared methacryloyl-terminated polyphenylene ether has a wide molecular weight distribution and low unsaturation.

[0160] Compared with Example 1, if no redistribution catalyst is added during the redistribution reaction (Comparative Example 2), the redistribution effect is poor, and the prepared hydroxyl-terminated polyphenylene ether has a wide molecular weight distribution and low hydroxyl value. Correspondingly, the prepared methacrylamide-terminated polyphenylene ether has a wide molecular weight distribution and low unsaturation.

[0161] Compared with Example 1, if no nucleophilic catalyst is added during the capping reaction (Comparative Example 3), the capping efficiency is low, and the prepared methacrylamide-capped polyphenylene ether has a high yellowness index, high impurity content, and low unsaturation.

[0162] Compared with Example 1, if no stabilizer is added during the capping reaction (Comparative Example 4), the prepared methacryloyl-capped polyphenylene ether has a wide molecular weight distribution, high yellowness index, high impurity content, and low unsaturation.

[0163] Compared with Example 1, if the end-capping reaction is carried out in a batch reactor (Comparative Example 5), the prepared methacryloyl-terminated polyphenylene ether has a wide molecular weight distribution, a high yellowness index, and a high impurity content.

[0164] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a methacryloyl-terminated polyphenylene ether, characterized in that, The preparation method includes the following steps: (1) Aromatic phenolic monomers are used to prepare prepolymers via a homogeneous method; (2) The prepolymer obtained in step (1) is mixed with the redistribution monomer and redistribution catalyst and reacted to obtain a hydroxyl-terminated polyphenylene ether solution; (3) The hydroxyl-terminated polyphenylene ether solution obtained in step (2), the double-bonded acyl chloride end-capping agent, the nucleophilic catalyst and the stabilizer are reacted in a microchannel reactor to obtain the methacryl-terminated polyphenylene ether; The redistribution monomer is tetramethylhydroquinone, and the redistribution catalyst includes dicumyl peroxide.

2. The preparation method according to claim 1, characterized in that, The aromatic phenolic monomers include phenolic monomers and aromatic diphenol monomers; The phenolic monomers include 2,6-dimethylphenol and / or 2,3,6-trimethylphenol; The aromatic diphenol monomers include tetramethylbisphenol F and / or tetramethylbisphenol A; The molar ratio of the phenolic monomer to the aromatic diphenol monomer is (32~37):1; The homogeneous method uses solvents including good solvents; The good solvent includes any one or a combination of at least two of benzene, toluene, ethylbenzene, xylene, chloroform, dichloroethane, trichloroethane, or chlorobenzene; In step (1), the mass ratio of solvent to aromatic phenolic monomer used in the homogeneous method is (2~5):

1.

3. The preparation method according to claim 2, characterized in that, The homogeneous preparation of the prepolymer in step (1) is carried out under the catalysis of a copper-based catalyst system; The copper-based catalyst system includes a copper-based catalyst, ligands, and additives; The copper-based catalyst includes cuprous compounds and / or copper compounds; The cuprous compound includes any one or a combination of at least two of cuprous chloride, cuprous bromide, cuprous nitrate or cuprous sulfate; The copper compound includes any one or a combination of at least two of copper chloride, copper bromide, copper nitrate or copper sulfate; The molar ratio of the copper-based catalyst to the phenolic monomer is (0.001~0.008):1; The ligands include amine compounds; The amine compounds include any one or a combination of at least two of the following: n-propylamine, isopropylamine, n-butylamine, cyclohexylamine, di-n-propylamine, triethylamine, or tetramethylethylenediamine; The molar ratio of the ligand to the copper-based catalyst is (0.5~5):1; The additives include azodicarbonate; The azodicarbonate includes any one or a combination of at least two of diethyl azodicarbonate, diisopropyl azodicarbonate, or tert-butyl azodicarbonate. The molar ratio of the additive to the copper-based catalyst is (0.05~2):

1.

4. The preparation method according to claim 2, characterized in that, The homogeneous preparation of the prepolymer in step (1) is carried out under conditions of passing an oxygen-containing gas; The volume concentration of oxygen in the oxygen-containing gas is 21% to 100%. In step (1), the amount of oxygen introduced per hour during the homogeneous preparation of the prepolymer is 0.6 to 3 times the amount of phenol monomers. The reaction temperature of the homogeneous method in step (1) is 30~70℃; The reaction time for the homogeneous method in step (1) is 45~90 min; The homogeneous reaction described in step (1) is carried out at a pressure of 0.8 to 1.25 bar; The molar ratio of the redistribution monomer to the aromatic diphenol monomer is (0.2~3):1; The mass of the redistribution catalyst in step (2) is 0.5% to 5% of the mass of the redistribution monomer; The reaction temperature in step (2) is 30~70℃; The reaction time in step (2) is 30~150 min; Step (2) further includes a step of removing water and part of the solvent after the reaction; The solid content of the hydroxyl-terminated polyphenylene ether solution in step (2) is 30%~50%.

5. The preparation method according to claim 1, characterized in that, Step (3) includes the following steps: mixing an acyl chloride end-capping agent containing double bonds, a nucleophilic catalyst, a stabilizer and a good solvent to form an end-capping agent solution; passing the hydroxyl-terminated polyphenylene ether solution obtained in step (2) and the end-capping agent solution together into a microchannel reactor for reaction to obtain the methacryloxy-terminated polyphenylene ether. The acyl chloride end-capping agent containing double bonds includes methacryloyl chloride; The nucleophilic catalyst includes 4-dimethylaminopyridine; The mass of the nucleophilic catalyst is 0.5% to 5% of the mass of the acyl chloride end-capping agent containing double bonds; The reaction in step (3) also includes the addition of alkali to carry out the reaction; The base includes any one or a combination of at least two of pyridine, diethylamine, or triethylamine; The molar ratio of the base to the acyl chloride end-capping agent containing double bonds is (0.8~1.5):1; The stabilizer includes triethyl phosphite; The mass of the stabilizer is 0.5% to 5% of the mass of the acyl chloride end-capping agent containing double bonds; The mass ratio of the good solvent to the double-bonded acyl chloride end-capping agent in the end-capping agent solution is (0.5~2):1; The molar amount of the acyl chloride end-capping agent containing double bonds satisfies the following formula: M = (n × HV × m) / 56000, where M represents the molar amount of the acyl chloride end-capping agent containing double bonds, n is 0.95~1.1, HV represents the hydroxyl value of the hydroxyl-terminated polyphenylene ether, and m represents the mass of the hydroxyl-terminated polyphenylene ether.

6. The preparation method according to claim 1, characterized in that, The aspect ratio of the microchannel reactor in step (3) is ≥100; The reaction temperature in the microchannel reactor described in step (3) is 40~90℃; The residence time of the material in the microchannel reactor in step (3) is 1 to 5 minutes.

7. The preparation method according to claim 1, characterized in that, Step (3) further includes washing, precipitation and drying steps after the reaction; The washing process includes washing with an aqueous hydrochloric acid solution and an aqueous ethylenediaminetetraacetic acid solution. The mass concentration of the hydrochloric acid aqueous solution is 0.5%~3%; The mass concentration of the ethylenediaminetetraacetic acid aqueous solution is 1%~5%; The precipitation includes precipitation in unsuitable solvents; The undesirable solvents include methanol.

8. A methacryloyl-terminated polyphenylene ether, characterized in that, The methacryloyl-terminated polyphenylene ether is prepared by the preparation method according to any one of claims 1 to 7.

9. The methacryloyl-terminated polyphenylene ether according to claim 8, characterized in that, The degree of unsaturation of the methacrylamide-terminated polyphenylene ether is ≥1.7; The number average molecular weight of the methacrylamide-terminated polyphenylene ether is 1000~3500; The molecular weight distribution of the methacryloyl-terminated polyphenylene ether is ≤2.

25.

10. The methacryloyl-terminated polyphenylene ether according to claim 8, characterized in that, The yellowness index of the methacrylamide-terminated polyphenylene ether is ≤10.

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