A method for preparing hyperbranched epoxy polymers, its products, and applications.

Abstract

This invention discloses a method for preparing a hyperbranched epoxy polymer, using a mixture of a first acrylate monomer, a second acrylate monomer, and carbon monoxide as raw materials, and synthesizing the hyperbranched epoxy polymer in a one-pot process under the action of a catalyst and an intermediate initiator; the catalyst is (Salen)Fe III The invention discloses a -X complex, where X is one of a halogen, nitrate, or acetate group; the first acrylate monomer is an acrylate compound containing both an epoxy group and a double bond, and the second acrylate monomer is an acrylate compound containing both an aromatic group and a double bond. The invention also discloses corresponding products and applications. This invention uses (Salen)Fe-X as a catalyst to copolymerize a mixture of acrylate monomers and carbon monoxide, enabling a one-step, highly selective, and highly active synthesis of hyperbranched epoxy polymers, thereby solving the problems of low synthesis efficiency and limited structural control of hyperbranched polymers prepared by existing technologies.

Description

Technical Field

[0001] This invention belongs to the field of polymer synthesis technology, specifically relating to a method for preparing hyperbranched epoxy polymers, their products, and applications. Background Technology

[0002] Hyperbranched polymers are dendritic macromolecules composed of a series of branched units, possessing a unique three-dimensional, highly branched topological structure. Compared to traditional linear polymers, hyperbranched polymers exhibit excellent solubility, lower viscosity, intramolecular cavities, and a large number of terminal functional groups, making them a research hotspot in polymer science with potential applications in coatings, drug carriers, and processing aids. In recent years, the modification of epoxy resins with hyperbranched polymers has attracted widespread attention. As a novel epoxy modifier, it can simultaneously improve the thermal and mechanical properties of epoxy resins without reducing their processability.

[0003] Currently, hyperbranched polymers have been synthesized through various methods, which can be divided into two categories based on the number of monomers used: monomonomer (SM) and dimonomer (DM) methods. These methods mainly include: (1) step-growth polycondensation of AB2 type monomers; (2) self-condensing vinyl polymerization (SCVP); (3) self-condensing ring-opening polymerization (SCROP); (4) proton transfer polymerization; (5) A2+B3 method; and (6) coupling monomer method. Among these, step-growth polycondensation of AB2 type monomers and SCVP are the most widely used methods. Step-growth polycondensation of AB2 type monomers cannot control the polymerization reaction, which to some extent limits the molecular weight and polydispersity of the polymer. The steps for synthesizing hyperbranched polymers by SCVP are relatively simple, but due to the existence of the step-growth mechanism, the monomers and oligomers react randomly with the growing polymer chains, resulting in polymers with polydisperse and irregular branched structures, failing to achieve precise control over the structure. In summary, there are various chemical synthesis methods for hyperbranched polymers. Several one-step methods for synthesizing hyperbranched polymers have been developed, but they suffer from drawbacks such as difficult monomer synthesis, cumbersome operation, and limited structural control. Therefore, the precise and efficient synthesis of hyperbranched polymers remains a challenge.

[0004] To address the aforementioned challenges, a switchable polymerization method is employed to synthesize hyperbranched polymers from readily available heterofunctional raw materials in a one-pot process. This method utilizes a single catalytic system where the catalyst's chemical reactivity selectively switches between various states under external stimuli, exhibiting excellent activity for different polymerization reactions. Copolymers are prepared from a monomer mixture in a one-pot process, achieving spatial and temporal control of the polymerization reaction. Commonly used external stimuli include light, heat, redox reactions, voltage, and mechanical force. Selecting visible light as the external stimulus for reaction regulation offers advantages such as environmental friendliness, ease of operation, and mild conditions. This emerging polymerization method not only enables precise control over the polymer material structure but also avoids laborious intermediate purification steps and minimizes catalyst usage.

[0005] In recent years, tetradentate Schiff alkali metal complex (Salen) catalyst systems have developed rapidly, and can be used for the ring-opening copolymerization of epoxy compounds / cyclic anhydrides, epoxy compounds / carbon dioxide, and heterocyclic compounds. Some catalysts have been commercialized. Among them, (Salen)Fe-X complexes are relatively easy to synthesize, the resulting metal complexes are stable, and optimal catalytic activity can be obtained without co-catalysts. They also exhibit high selectivity for polymers and excellent regioselectivity. Therefore, (Salen)Fe-X complexes not only have great potential in the synthesis of polycarbonates, but also in the synthesis of hyperbranched epoxy polymers. Summary of the Invention

[0006] To address one or more of the above-mentioned defects or improvement needs of existing technologies, this invention provides a method for preparing hyperbranched epoxy polymers, as well as their products and applications. Using (Salen)Fe-X as a catalyst, a copolymerization reaction of an acrylate monomer mixture and carbon monoxide is carried out, enabling a one-step, highly selective, and highly active synthesis of hyperbranched epoxy polymers. This solves the technical problems of low synthesis efficiency and limited structural control of hyperbranched polymers prepared by existing technologies.

[0007] To achieve the above objectives, according to the first aspect of the present invention, a method for preparing a hyperbranched epoxy polymer is provided, wherein the hyperbranched epoxy polymer is synthesized in one pot using a mixture of a first acrylate monomer, a second acrylate monomer, and carbon monoxide as raw materials, under the action of a catalyst and an intermediate initiator.

[0008] The catalyst is (Salen)Fe III -X complex, where X is one of halogen, nitrate or acetate; the first acrylate monomer is an acrylate compound containing both an epoxy group and a double bond, and the second acrylate monomer is an acrylate compound containing both an aromatic group and a double bond.

[0009] As a further improvement to the present invention, the following steps are specifically included:

[0010] (1) Under a protective atmosphere and under oxygen-free and anhydrous conditions, the first acrylate monomer and the catalyst are first thoroughly mixed in a reactor, and then carbon monoxide is introduced into the reactor to carry out a ring-opening reaction to obtain an intermediate initiator.

[0011] (2) Under a protective atmosphere and under oxygen-free and anhydrous conditions, the intermediate initiator, the first acrylate monomer and the second acrylate monomer are thoroughly mixed in a reactor. Under visible light, the intermediate initiator initiates the copolymerization reaction of the mixture of the first acrylate monomer and the second acrylate monomer to obtain a hyperbranched epoxy polymer.

[0012] As a further improvement of the present invention, the first acrylate monomer includes one or more of glycidyl acrylate, 4-hydroxybutyl acrylate glycidyl ether, and (3,4-epoxycyclohexyl) methyl acrylate; and / or,

[0013] The second acrylate monomer includes one or more of methyl 1-pyrene acrylate, benzyl acrylate, (1-pyrene)methyl methacrylate, and benzyl methacrylate.

[0014] As a further improvement of the present invention

[0015] In step (1), the molar ratio of the catalyst to the first acrylate monomer is 1:1 to 2; and / or,

[0016] In step (2), the molar ratio of the intermediate initiator and the first acrylate monomer is 1:10 to 30; the molar ratio of the first acrylate monomer and the second acrylate monomer is 1 to 5:1.

[0017] As a further improvement of the present invention

[0018] In step (1), the temperature of the ring-opening reaction is 0–40°C; the time of the ring-opening reaction is 8–48 h; and / or,

[0019] In step (1), the pressure at which carbon monoxide is introduced is 1–4 MPa; and / or,

[0020] In step (2), the copolymerization reaction temperature is 0–40°C, and the copolymerization reaction time is 48–80 h; and / or,

[0021] In step (2), the intensity of the visible light is 3–15 mW·cm. -2 .

[0022] As a further improvement of the present invention, the catalyst has the following structural formula:

[0023]

[0024] In the formula, X is a halogen, nitrate, or acetate.

[0025] According to a second aspect of the present invention, a hyperbranched epoxy polymer is provided, which is obtained by the preparation method described above.

[0026] As a further improvement of the present invention, its general structural formula is:

[0027]

[0028] Where (a) is a branched unit, (b) is a linear unit, and (c) is a terminal unit;

[0029] In the formula, R1 is one of the following structural formulas:

[0030]

[0031] R2 is one of the following structural formulas:

[0032]

[0033] X is one of the following structural formulas:

[0034] *-Cl*-Br*—I*-NO3CH3COO-*.

[0035] As a further improvement of the present invention, the number-average molecular weight of the hyperbranched epoxy polymer is 45,000 to 88,000.

[0036] According to a third aspect of the present invention, a hyperbranched epoxy polymer is provided as an epoxy modifier or as a dispersant for thermally conductive fillers containing aromatic groups, wherein the hyperbranched epoxy polymer is used, or the hyperbranched epoxy polymer is prepared by the preparation method described above.

[0037] When the hyperbranched epoxy polymer is used as an epoxy modifier to prepare epoxy resin compositions, the high-density epoxy groups of the hyperbranched epoxy polymer of the present invention further improve its compatibility in epoxy matrix and further improve the toughness of epoxy system through flexible chains in structure. When the hyperbranched epoxy polymer is used as a dispersant for thermally conductive fillers containing aromatic groups to prepare thermally conductive composite materials, the hyperbranched epoxy polymer of the present invention introduces aromatic groups, and therefore can be used as a dispersant for thermally conductive fillers containing aromatic groups, and can be used to prepare thermally conductive composite materials.

[0038] This invention utilizes a mixture of a first acrylate monomer, a second acrylate monomer, and carbon monoxide as raw materials to synthesize hyperbranched epoxy polymers in a one-pot process under the action of a catalyst. The catalyst in this invention is Fe. III -X complexes act as both catalysts and initiators. First, (Salen)Fe III The -X complex catalyzes the regioselective ring-opening reaction of the first acrylate monomer to generate an acrylate-functionalized ferro-bonded intermediate. Carbon monoxide quantitatively converts the ferro-bonded intermediate into an iron-carbon bond via a migration-insertion mechanism, thus synthesizing the intermediate initiator in situ. Under visible light, the initiator undergoes homolytic cleavage of the iron-carbon bond to generate an acrylate-functionalized carbonyl radical, which initiates a radical copolymerization reaction of the acrylate monomer mixture. This carbonyl radical acts as a branching site, generating a hyperbranched epoxy polymer with a narrow molecular weight distribution. The synthesized hyperbranched epoxy polymer can be used in epoxy resin modifiers, processing aids, and other fields. The preparation method provided by this invention can directly synthesize hyperbranched epoxy polymers in a one-pot process. Through a switchable polymerization reaction regulated by visible light, hyperbranched epoxy polymers are synthesized from a mixture of acrylate monomers in a one-pot process. The process is simple, easy to operate, and allows for precise control of the polymer structure.

[0039] In summary, the technical solutions conceived by this invention have the following beneficial effects compared with the prior art:

[0040] (1) This invention utilizes the carbonylation reaction of carbon monoxide to rapidly and quantitatively insert carbon monoxide into the iron-oxygen bond (Fe-O), thereby converting the intermediate (Salen) Fe of the ring-opening reaction into a carbonylation reaction. III -OR in situ conversion to OMR-SCVP photoinitiator (Salen) Fe III -CO2R, thereby achieving a smart conversion from the ring-opening reaction of epoxides to the OMR-SCVP reaction of non-conjugated vinyl monomers. (Salen)Fe III Using X as a switchable catalyst and carbon monoxide as a molecular switch, a one-pot synthesis strategy for the switchable polymerization of hyperbranched epoxy polymers is constructed under visible light regulation.

[0041] (2) By optimizing the structure of the catalyst, this invention can synthesize hyperbranched epoxy polymers in one step with high selectivity and high activity. The reaction process is simple and easy to operate, which reduces the cost of raw materials and labor and improves production efficiency.

[0042] (3) This invention employs a visible light-controlled switchable polymerization method to synthesize hyperbranched polymers from readily available bifunctional raw materials in a one-pot process. Choosing visible light as an external stimulus to regulate the reaction offers advantages such as environmental friendliness, ease of operation, and mild conditions. Furthermore, the preparation method provided by this invention features relatively mild reaction conditions and no temperature surge. Additionally, during the polymerization stage, the reaction is monitored by periodically taken samples using 1H NMR spectroscopy. Under white light irradiation, the polymerization proceeds smoothly, and the monomer conversion rate gradually increases; however, without white light irradiation, the polymerization stops. This indicates that a truly on / off active photopolymerization system can be developed, and this on / off cycle can be repeated multiple times. Therefore, the "on / off" effect of visible light can be used to precisely control the hyperbranched chain growth process, thereby regulating the relative molecular mass and degree of branching of the hyperbranched epoxy compound. Attached Figure Description

[0043] Figure 1 This is a copolymerization mechanism diagram of the hyperbranched epoxy polymer synthesized in Example 1.

[0044] Figure 2 This is a schematic diagram of the synthesis reaction of the hyperbranched epoxy polymer in Example 1.

[0045] Figure 3 These are the Mark-Houwink curves for the hyperbranched epoxy polymer and the corresponding linear polymer obtained in Example 1. Linear polymer (M... n =13.6kDa, The Mark-Houwink index (α) of the polymer was 0.60, while that of the hyperbranched polymer (M) was much higher. n =17.9kDa, The Mark-Houwink index (α) of the synthesized polymer is 0.43, which proves that the synthesized polymer is a hyperbranched polymer. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0047] This invention provides a method for preparing a hyperbranched epoxy polymer. The method uses a mixture of a first acrylate monomer, a second acrylate monomer, and carbon monoxide as raw materials, and synthesizes the hyperbranched epoxy polymer in a one-pot process under the action of a catalyst and an initiator.

[0048] Specifically, it includes the following steps:

[0049] (1) Under a protective atmosphere and under oxygen-free and anhydrous conditions, the first acrylate monomer and the catalyst are first thoroughly mixed in a reactor, and then carbon monoxide is introduced into the reactor to carry out a ring-opening reaction to obtain an intermediate initiator.

[0050] (2) Under a protective atmosphere and under oxygen-free and anhydrous conditions, the intermediate initiator, the first acrylate monomer and the second acrylate monomer are thoroughly mixed in a reactor. Under visible light, the intermediate initiator initiates the copolymerization reaction of the mixture of the first acrylate monomer and the second acrylate monomer to obtain a hyperbranched epoxy polymer.

[0051] The catalyst is preferably (Salen)Fe III -X complex, where X is one of halogen, nitrate, or acetate; the specific structural formula of the catalyst is:

[0052]

[0053] Wherein, X is one of halogen, nitrate or acetate.

[0054] Furthermore, the first acrylate monomer is preferably an acrylate compound containing both an epoxy group and a double bond. As a heterofunctional monomer, it can form a cobalt-carbon bond intermediate for acrylate functionalization through a cobalt-catalyzed ring-opening reaction under a carbon monoxide atmosphere. The second acrylate monomer is preferably an acrylate compound containing both an aromatic group and a double bond. The introduction of aromatic groups enables the hyperbranched polymer to have both rigid and flexible segments, resulting in excellent comprehensive properties.

[0055] More preferably, the first acrylate monomer includes one or more of glycidyl acrylate, 4-hydroxybutyl acrylate glycidyl ether, and (3,4-epoxycyclohexyl) methyl acrylate. The second acrylate monomer includes one or more of methyl 1-pyrene acrylate, benzyl acrylate, (1-pyrene) methyl methacrylate, and benzyl methacrylate.

[0056] It should be noted that in step (1), the first acrylate monomer, as a heterofunctional monomer, can undergo a ring-opening reaction with high regioselectivity under a carbon monoxide atmosphere, forming an intermediate initiator in situ; in step (2), the first acrylate monomer participates in the reaction as a comonomer, providing a high density of epoxy groups.

[0057] In a preferred embodiment, in step (1), the molar ratio of the catalyst to the first acrylate monomer is 1:1 to 2.

[0058] In a preferred embodiment, in step (2), the molar ratio of the intermediate initiator and the first acrylate monomer is 1:10 to 30; the molar ratio of the first acrylate monomer and the second acrylate monomer is 1 to 5:1, so as to ensure that the obtained hyperbranched epoxy polymer chain contains a high density of epoxy groups.

[0059] In a preferred embodiment, in step (1), the temperature of the ring-opening reaction is 0–40°C; and the time of the ring-opening reaction is 8–48 h.

[0060] In step (1), the pressure of carbon monoxide is 1-4 MPa;

[0061] In step (2), the temperature of the copolymerization reaction is 0–40°C, and the time of the copolymerization reaction is 48–80 h;

[0062] In step (2), white LED lights are preferably used for illumination with visible light; the intensity of the visible light is 3–15 mW·cm. -2 Visible light plays a key role in the homolytic cleavage of Fe-C bonds. Within the above-mentioned preferred intensity range, light can easily penetrate the solution, thereby promoting the homolytic cleavage of Fe-C bonds.

[0063] Furthermore, the hyperbranched epoxy polymer obtained by the preparation method of the present invention has the following general structural formula:

[0064]

[0065] Where (a) is a branched unit, (b) is a linear unit, and (c) is a terminal unit;

[0066] In the formula, R1 is one of the following structural formulas:

[0067]

[0068] R2 is one of the following structural formulas:

[0069] *-CH2-*

[0070] X is one of the following structural formulas:

[0071] *-Cl*-Br*-l*-NO3CH3COO-*.

[0072] Preferably, the number average molecular weight of the hyperbranched epoxy polymer is 45,000 to 88,000.

[0073] The copolymerization reaction mechanism diagram of this invention is shown below. Figure 1 As shown, in the first stage, (salen)Fe III-X effectively activates the epoxide moiety of glycidyl acrylate through coordination, promoting the nucleophilic attack of the axial -X group on the sterically less hindrance methylene carbon, catalyzing the regioselective ring-opening reaction of glycidyl acrylate to generate an acrylate-functionalized ferrooxide intermediate. Then, the resulting (Salen)Fe III The -OR intermediate undergoes a carbonylation reaction, in which carbon monoxide first reacts with (Salen)Fe. III -OR directly coordinates to form [(Salen)Fe III The (CO)]OR adduct was subsequently synthesized via a migration insertion reaction and intramolecular rearrangement process. The photoinitiator (Salen)Fe was synthesized in situ by migrating carbon monoxide into the Fe-O bond. III -CO2R. When exposed to visible light, the reaction enters the second stage, where the initiator undergoes homolytic cleavage of iron-carbon bonds to generate acrylate-functionalized carbonyl radicals. These radicals can initiate free radical copolymerization of acrylate monomers via a linear pathway, or participate in the reaction as branching sites to generate hyperbranched epoxy polymers with narrow relative molecular mass distributions.

[0074] This invention also provides a specific method for preparing hyperbranched epoxy polymers, comprising the following steps:

[0075] Step 1: Under a protective atmosphere and under oxygen-free and anhydrous conditions, the first acrylate monomer, catalyst, and solvent (including but not limited to tetrahydrofuran, dichloromethane, and 1,4-dioxane) are thoroughly mixed in a reactor. Then, carbon monoxide is introduced into the reactor to obtain a reaction mixture. The reaction is carried out at 0–40°C for 8–48 hours. After the reaction is completed, the carbon monoxide in the reactor is released and the reaction is quenched to obtain a crude intermediate. After purification, the intermediate initiator is obtained.

[0076] Step 2: Under a protective atmosphere and under oxygen- and anhydrous conditions, the intermediate initiator, the first acrylate monomer, the second acrylate monomer, and the solvent (including but not limited to tetrahydrofuran, dichloromethane, and 1,4-dioxane) are thoroughly mixed in a reactor and stirred at 0–40°C for 48–80 h under white LED illumination. After the reaction is completed, the reaction system is allowed to stand and cool to room temperature to obtain the crude product. The crude product is then purified to obtain the hyperbranched epoxy polymer.

[0077] More preferably, the amount of solvent added is determined based on the amount of the first acrylate monomer added, wherein in step one, the concentration of the first acrylate monomer in the solvent ranges from 0.1 to 0.4 mol / L; and in step two, the concentration of the first acrylate monomer in the solvent ranges from 1 to 4 mol / L. However, this invention does not impose specific limitations on the solvent, and those skilled in the art can select the type and amount of solvent based on experience, as long as it can dissolve the reaction solute.

[0078] To better understand the preparation method and products of the present invention, the following specific embodiments and comparative examples are provided:

[0079] Example 1

[0080] The preparation method of the hyperbranched epoxy polymer in this embodiment includes the following steps:

[0081] Step 1: In a glove box filled with argon gas, add 1.92g of (Salen)Fe III The Cl compound, 690 μL of glycidyl acrylate, and 30 mL of tetrahydrofuran were loaded into a 100 mL reaction vessel, wrapped with aluminum foil, and equipped with a magnetic stirrer. The reaction vessel was then removed from the glove box and stirred at 1 atm CO2 and room temperature for 36 h. After the reaction was completed, carbon monoxide was released from the reactor to quench the reaction, yielding a crude intermediate. The crude intermediate was purified by silica gel chromatography to obtain the intermediate initiator.

[0082] Step 2: In an argon-filled glove box, dissolve 2.38 g of the intermediate initiator, 6.8 mL of glycidyl acrylate, and 4.29 g of methyl 1-pyrene acrylate in 24 mL of tetrahydrofuran, and transfer the solution to a 100 mL reaction vessel equipped with a magnetic stirrer. Then remove the reaction vessel from the glove box and test it using a light source with an intensity of 10 mW·cm². -2 Irradiated with a white LED light, the mixture was stirred at 25°C for 72 hours. After the reaction was completed, the reaction system was allowed to stand and cool to room temperature to obtain the cooled product liquid. This liquid was then repeatedly precipitated in cold methanol and dried to obtain the hyperbranched epoxy polymer.

[0083] Example 2

[0084] The preparation method of the hyperbranched epoxy polymer in this embodiment includes the following steps:

[0085] Step 1: In a glove box filled with argon gas, add 1.92g of (Salen)Fe IIIThe Cl complex, 644 μL of glycidyl acrylate, and 30 mL of tetrahydrofuran were loaded into a 100 mL reaction vessel, wrapped with aluminum foil, and equipped with a magnetic stirrer. The reaction vessel was then removed from the glove box and stirred at 1 atm CO2 and room temperature for 36 h. After the reaction was completed, carbon monoxide was released from the reactor to quench the reaction, yielding a crude intermediate. The crude intermediate was purified by silica gel chromatography to obtain the intermediate initiator.

[0086] Step 2: In an argon-filled glove box, dissolve 2.30 g of the intermediate initiator, 6.8 mL of glycidyl acrylate, and 4.29 g of methyl 1-pyrene acrylate in 24 mL of tetrahydrofuran, and transfer the solution to a 100 mL reaction vessel equipped with a magnetic stirrer. Then remove the reaction vessel from the glove box and test it using a light source with an intensity of 5 mW·cm². -2 Irradiated with a white LED light, the mixture was stirred at 25°C for 72 hours. After the reaction was completed, the reaction system was allowed to stand and cool to room temperature to obtain the cooled product liquid. This liquid was then repeatedly precipitated in cold methanol and dried to obtain the hyperbranched epoxy polymer.

[0087] Example 3

[0088] The preparation method of the hyperbranched epoxy polymer in this embodiment includes the following steps:

[0089] Step 1: In a glove box filled with argon gas, add 1.92g of (Salen)Fe III The Cl complex, 598 μL of glycidyl acrylate, and 25 mL of dichloromethane were loaded into a 100 mL reaction vessel, wrapped with aluminum foil, and equipped with a magnetic stirrer. The reaction vessel was then removed from the glove box and stirred at 1 atm CO2 and room temperature for 24 h. After the reaction was completed, carbon monoxide was released from the reactor to quench the reaction, yielding a crude intermediate. The crude intermediate was purified by silica gel chromatography to obtain the intermediate initiator.

[0090] Step 2: In an argon-filled glove box, dissolve 2.38 g of the intermediate initiator, 6.12 mL of glycidyl acrylate, and 4.00 g of methyl 1-pyrene acrylate in 20 mL of dichloromethane, and transfer the solution to a 100 mL reaction vessel equipped with a magnetic stirrer. Then remove the reaction vessel from the glove box and test it using a light source with an intensity of 10 mW·cm². -2 Irradiated with a white LED light, the mixture was stirred at 25°C for 70 hours. After the reaction was completed, the reaction system was allowed to stand and cool to room temperature to obtain the cooled product liquid. This liquid was then repeatedly precipitated in cold methanol and dried to obtain the hyperbranched epoxy polymer.

[0091] Example 4

[0092] The preparation method of the hyperbranched epoxy polymer in this embodiment includes the following steps:

[0093] Step 1: In a glove box filled with argon gas, add 1.92g of (Salen)Fe III The Cl complex, 552 μL of glycidyl acrylate, and 25 mL of dichloromethane were loaded into a 100 mL reaction vessel, wrapped with aluminum foil, and equipped with a magnetic stirrer. The reaction vessel was then removed from the glove box and stirred at 1 atm CO2 and room temperature for 24 h. After the reaction was completed, carbon monoxide was released from the reactor to quench the reaction, yielding a crude intermediate. The crude intermediate was purified by silica gel chromatography to obtain the intermediate initiator.

[0094] Step 2: In an argon-filled glove box, dissolve 2.38 g of the intermediate initiator, 7.48 mL of glycidyl acrylate, and 4.72 g of methyl 1-pyrene acrylate in 30 mL of dichloromethane, and transfer the solution to a 100 mL reaction vessel equipped with a magnetic stirrer. Then remove the reaction vessel from the glove box and test it using a light source with an intensity of 10 mW·cm². -2 Irradiated with a white LED light, the mixture was stirred at 25°C for 72 hours. After the reaction was completed, the reaction system was allowed to stand and cool to room temperature to obtain the cooled product liquid. This liquid was then repeatedly precipitated in cold methanol and dried to obtain the hyperbranched epoxy polymer.

[0095] Example 5

[0096] The preparation method of the hyperbranched epoxy polymer in this embodiment includes the following steps:

[0097] Step 1: In a glove box filled with argon gas, add 1.92g of (Salen)Fe III The Cl complex, 680 μL of glycidyl acrylate, and 30 mL of 1,4-dioxane were loaded into a 100 mL reaction vessel, wrapped with aluminum foil, and equipped with a magnetic stirrer. The reaction vessel was then removed from the glove box and stirred at 1 atm CO2 and room temperature for 48 h. After the reaction was completed, carbon monoxide was released from the reactor to quench the reaction, yielding a crude intermediate. The crude intermediate was purified by silica gel chromatography to obtain the intermediate initiator.

[0098] Step 2: In an argon-filled glove box, dissolve 2.30 g of the intermediate initiator, 7.48 mL of glycidyl acrylate, and 3.78 g of methyl 1-pyrene acrylate in 30 mL of 1,4-dioxane, and transfer the solution to a 100 mL reaction vessel equipped with a magnetic stirrer. Then remove the reaction vessel from the glove box and test it using a light source with an intensity of 10 mW·cm². -2 Irradiated with a white LED light, the mixture was stirred at 25°C for 80 hours. After the reaction was completed, the reaction system was allowed to stand and cool to room temperature to obtain the cooled product liquid. This liquid was then repeatedly precipitated in cold methanol and dried to obtain the hyperbranched epoxy polymer.

[0099] Example 6

[0100] The preparation method of the hyperbranched epoxy polymer in this embodiment includes the following steps:

[0101] Step 1: In a glove box filled with argon gas, add 1.92g of (Salen)Fe III The Br complex, 720 μL of 4-hydroxybutylacrylate glycidyl ether, and 30 mL of tetrahydrofuran were placed in a 100 mL reaction vessel, wrapped with aluminum foil, and equipped with a magnetic stirrer. The reaction vessel was then removed from the glove box and stirred at 1 atm CO and room temperature for 36 h. After the reaction was completed, carbon monoxide was released from the reactor to quench the reaction, yielding a crude intermediate. The crude intermediate was purified by silica gel chromatography to obtain the intermediate initiator.

[0102] Step 2: In an argon-filled glove box, dissolve 2.38 g of the intermediate initiator, 7.7 mL of 4-hydroxybutylacrylate glycidyl ether, and 4.29 g of 1-pyrene methyl acrylate in 24 mL of tetrahydrofuran, and transfer the solution to a 100 mL reaction vessel equipped with a magnetic stirrer. Then remove the reaction vessel from the glove box and test it using a light source with an intensity of 10 mW·cm². -2 Irradiated with a white LED light, the mixture was stirred at 25°C for 72 hours. After the reaction was completed, the reaction system was allowed to stand and cool to room temperature to obtain the cooled product liquid. This liquid was then repeatedly precipitated in cold methanol and dried to obtain the hyperbranched epoxy polymer.

[0103] Example 7

[0104] The preparation method of the hyperbranched epoxy polymer in this embodiment includes the following steps:

[0105] Step 1: In a glove box filled with argon gas, add 1.92g of (Salen)Fe III The Br complex, 690 μL of 4-hydroxybutylacrylate glycidyl ether, and 30 mL of tetrahydrofuran were placed in a 100 mL reaction vessel, wrapped with aluminum foil, and equipped with a magnetic stirrer. The reaction vessel was then removed from the glove box and stirred at 1 atm CO and room temperature for 36 h. After the reaction was completed, carbon monoxide was released from the reactor to quench the reaction, yielding a crude intermediate. The crude intermediate was purified by silica gel chromatography to obtain the intermediate initiator.

[0106] Step 2: In an argon-filled glove box, dissolve 2.30 g of the intermediate initiator, 6.8 mL of 4-hydroxybutylacrylate glycidyl ether, and 4.29 g of 1-pyrene methyl acrylate in 24 mL of tetrahydrofuran, and transfer the solution to a 100 mL reaction vessel equipped with a magnetic stirrer. Then remove the reaction vessel from the glove box and test it using a light source with an intensity of 5 mW·cm². -2Irradiated with a white LED light, the mixture was stirred at 25°C for 72 hours. After the reaction was completed, the reaction system was allowed to stand and cool to room temperature to obtain the cooled product liquid. This liquid was then repeatedly precipitated in cold methanol and dried to obtain the hyperbranched epoxy polymer.

[0107] Example 8

[0108] The preparation method of the hyperbranched epoxy polymer in this embodiment includes the following steps:

[0109] Step 1: In a glove box filled with argon gas, add 1.92g of (Salen)Fe III The NO3 complex, 598 μL of 4-hydroxybutyl acrylate glycidyl ether, and 25 mL of tetrahydrofuran were loaded into a 100 mL reaction vessel, wrapped with aluminum foil, and equipped with a magnetic stirrer. The reaction vessel was then removed from the glove box and stirred at 1 atm CO and room temperature for 24 h. After the reaction was completed, carbon monoxide was released from the reactor to quench the reaction, yielding a crude intermediate. The crude intermediate was purified by silica gel chromatography to obtain the intermediate initiator.

[0110] Step 2: In an argon-filled glove box, dissolve 2.38 g of the intermediate initiator, 6.12 mL of 4-hydroxybutylacrylate glycidyl ether, and 4.00 g of benzyl acrylate in 20 mL of tetrahydrofuran, and transfer the solution to a 100 mL reaction vessel equipped with a magnetic stirrer. Then remove the reaction vessel from the glove box and test it using a light source with an intensity of 10 mW·cm². -2 Irradiated with a white LED light, the mixture was stirred at 25°C for 70 hours. After the reaction was completed, the reaction system was allowed to stand and cool to room temperature to obtain the cooled product liquid. This liquid was then repeatedly precipitated in cold methanol and dried to obtain the hyperbranched epoxy polymer.

[0111] Example 9

[0112] The preparation method of the hyperbranched epoxy polymer in this embodiment includes the following steps:

[0113] Step 1: In a glove box filled with argon gas, add 1.92g of (Salen)Fe III The NO3 complex, 552 μL of methyl (3,4-epoxycyclohexyl) acrylate, and 25 mL of 1,4-dioxane were loaded into a 100 mL reaction vessel, wrapped with aluminum foil, and equipped with a magnetic stirrer. The reaction vessel was then removed from the glove box and stirred at 1 atm CO2 and room temperature for 24 h. After the reaction was complete, carbon monoxide was released from the reactor to quench the reaction, yielding a crude intermediate. The crude intermediate was purified by silica gel chromatography to obtain the intermediate initiator.

[0114] Step 2: In an argon-filled glove box, dissolve 2.38 g of the intermediate initiator, 7.48 mL of methyl (3,4-epoxycyclohexyl) acrylate, and 4.72 g of benzyl acrylate in 30 mL of 1,4-dioxane, and transfer the solution to a 100 mL reaction vessel equipped with a magnetic stirrer. Then remove the reaction vessel from the glove box and test it using a light source with an intensity of 10 mW·cm². -2 Irradiated with a white LED light, the mixture was stirred at 25°C for 72 hours. After the reaction was completed, the reaction system was allowed to stand and cool to room temperature to obtain the cooled product liquid. This liquid was then repeatedly precipitated in cold methanol and dried to obtain the hyperbranched epoxy polymer.

[0115] Example 10

[0116] The preparation method of the hyperbranched epoxy polymer in this embodiment includes the following steps:

[0117] Step 1: In a glove box filled with argon gas, add 1.92g of (Salen)Fe III The NO3 complex, 680 μL of methyl (3,4-epoxycyclohexyl) acrylate, and 30 mL of tetrahydrofuran were loaded into a 100 mL reaction vessel, wrapped with aluminum foil, and equipped with a magnetic stirrer. The reaction vessel was then removed from the glove box and stirred at 1 atm CO2 and room temperature for 48 h. After the reaction was complete, carbon monoxide was released from the reactor to quench the reaction, yielding a crude intermediate. The crude intermediate was purified by silica gel chromatography to obtain the intermediate initiator.

[0118] Step 2: In an argon-filled glove box, dissolve 2.30 g of the intermediate initiator, 7.48 mL of (3,4-epoxycyclohexyl) methyl acrylate, and 3.78 g of benzyl acrylate in 30 mL of tetrahydrofuran, and transfer the solution to a 100 mL reaction vessel equipped with a magnetic stirrer. Then remove the reaction vessel from the glove box and test it using a light source with an intensity of 10 mW·cm². -2 Irradiated with a white LED light, the mixture was stirred at 25°C for 80 hours. After the reaction was completed, the reaction system was allowed to stand and cool to room temperature to obtain the cooled product liquid. This liquid was then repeatedly precipitated in cold methanol and dried to obtain the hyperbranched epoxy polymer.

[0119] Comparative Example 1

[0120] The preparation method of the hyperbranched epoxy polymer in this comparative example includes the following steps:

[0121] Step 1: In a glove box filled with argon gas, add 0.96g of (Salen)Fe IIIThe Cl complex, 1.36 mL of glycidyl acrylate, and 40 mL of tetrahydrofuran were placed in a 100 mL reaction vessel, wrapped with aluminum foil, and equipped with a magnetic stirrer. The reaction vessel was then removed from the glove box and stirred at 1 atm CO and room temperature for 36 h. After the reaction was completed, carbon monoxide was released from the reactor to quench the reaction, yielding a crude intermediate. The crude intermediate was purified by silica gel chromatography to obtain the intermediate initiator.

[0122] Step 2: In an argon-filled glove box, dissolve 0.24 g of the intermediate initiator, 20.40 mL of glycidyl acrylate, and 12.87 g of methyl 1-pyrene acrylate in 30 mL of tetrahydrofuran, and transfer the solution to a 100 mL reaction vessel equipped with a magnetic stirrer. Then remove the reaction vessel from the glove box and test it using a light source with an intensity of 1 mW·cm². -2 Irradiated with a white LED light, the mixture was stirred at 25°C for 50 hours. After the reaction was completed, the reaction system was allowed to stand and cool to room temperature to obtain the cooled product liquid. This liquid was then repeatedly precipitated in cold methanol and dried to obtain the hyperbranched epoxy polymer.

[0123] The performance of Examples 1-5 and Comparative Example 1 was characterized. The molecular weight distribution of each sample was measured using an Agilent PLGPC50 gel permeation chromatography (GPC) instrument. Number average molecular weight (M n The conversion rates of glycidyl acrylate and methyl 1-pyrene acrylate were measured using proton nuclear magnetic resonance spectroscopy, and the characterization results are shown in Table 1.

[0124] Table 1 Performance characterization results of Examples 1-5 and Comparative Example 1

[0125]

[0126] As shown in Table 1, the monomer conversion rates of the hyperbranched epoxy polymers prepared in Examples 1-5 were all greater than 50%, indicating that the polymerization reaction proceeded smoothly and more than half of the monomers were successfully converted into polymers. The Mark-Houwink indices of the hyperbranched epoxy polymers prepared in Examples 1-5 were in the range of 0.21-0.44, which is consistent with the characteristics of hyperbranched polymers. In contrast, the hyperbranched epoxy polymer prepared in Comparative Example 1 had a low monomer conversion rate, making the polymerization reaction difficult to proceed, resulting in a relatively small molecular weight of the polymer. Furthermore, the Mark-Houwink indices of the hyperbranched epoxy polymer prepared in Comparative Example 1 were in the range of 0.6-0.8, which is consistent with the characteristics of linear polymers.

[0127] This is because the feed ratio of the intermediate initiator to the comonomer in Comparative Example 1 was significantly reduced, and the reaction time was not extended, resulting in a decrease in the branching degree of the hyperbranched epoxy polymer as the feed ratio decreased. Simultaneously, since the reaction rate of living / controlled radical polymerization is positively correlated with the concentration of free radicals, when the feed ratio of the intermediate initiator to the comonomer is reduced, the free radical concentration in the entire reaction system is very low, making it difficult to initiate monomer polymerization and limiting the polymerization rate, resulting in a low conversion rate of the hyperbranched epoxy polymer. Furthermore, in Comparative Example 1, the light intensity affected the homolytic cleavage of the Fe-C bonds; not all intermediate initiators could successfully convert into carbon-centered free radicals, thus affecting the polymerization rate. Therefore, the various indicators of Comparative Example 1 differ significantly from those of Examples 1-5, making it unsuitable for practical use.

[0128] The above embodiments are merely examples. For instance, the protective atmosphere may be nitrogen or other inert gases in addition to argon.

[0129] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a hyperbranched epoxy polymer, characterized in that, Includes the following steps: (1) Under a protective atmosphere and under oxygen-free and anhydrous conditions, the first acrylate monomer and the catalyst are first thoroughly mixed in a reactor, and then carbon monoxide is introduced into the reactor to carry out a ring-opening reaction to obtain an intermediate initiator. (2) Under a protective atmosphere and under oxygen-free and anhydrous conditions, the intermediate initiator, the first acrylate monomer and the second acrylate monomer are thoroughly mixed in a reactor. Under visible light, the intermediate initiator initiates the copolymerization reaction of the mixture of the first acrylate monomer and the second acrylate monomer to obtain a hyperbranched epoxy polymer. In step (1), the molar ratio of the catalyst to the first acrylate monomer is 1:1~2; In step (2), the molar ratio of the intermediate initiator to the first acrylate monomer is 1:10~30; the molar ratio of the first acrylate monomer to the second acrylate monomer is 1~5:1; and the intensity of the visible light is 3~15 mW·cm. -2 ; The catalyst is (Salen)Fe III -X complex, where X is one of halogen, nitrate or acetate; The first acrylate monomer includes one or more of glycidyl acrylate, 4-hydroxybutyl acrylate glycidyl ether, and (3,4-epoxycyclohexyl) methyl acrylate; The second acrylate monomer includes one or more of methyl 1-pyrene acrylate, benzyl acrylate, (1-pyrene)methyl methacrylate, and benzyl methacrylate.

2. The method for preparing the hyperbranched epoxy polymer according to claim 1, characterized in that, In step (1), the temperature of the ring-opening reaction is 0~40℃; the time of the ring-opening reaction is 8~48 h.

3. The method for preparing the hyperbranched epoxy polymer according to claim 1, characterized in that, In step (1), the pressure of carbon monoxide being introduced is 1~4 MPa.

4. The method for preparing the hyperbranched epoxy polymer according to claim 1, characterized in that, In step (2), the temperature of the copolymerization reaction is 0~40°C and the time of the copolymerization reaction is 48~80 h.

5. The method for preparing the hyperbranched epoxy polymer according to any one of claims 1-4, characterized in that, The structural formula of the catalyst is: (A) In the formula, X is a halogen, nitrate, or acetate.

6. A hyperbranched epoxy polymer, obtained by the preparation method according to any one of claims 1-5.

7. The hyperbranched epoxy polymer according to claim 6, wherein the number-average molecular weight of the hyperbranched epoxy polymer is 45,000 to 88,000.

8. The application of a hyperbranched epoxy polymer as an epoxy modifier or as a dispersant for thermally conductive fillers containing aromatic groups, wherein the hyperbranched epoxy polymer of claim 6 or 7 is used, or the hyperbranched epoxy polymer prepared by any one of the preparation methods of claims 1-5 is used. The hyperbranched epoxy polymer is used as an epoxy modifier to prepare epoxy resin compositions. The hyperbranched epoxy polymer is used as a dispersant for thermally conductive fillers containing aromatic groups to prepare thermally conductive composite materials.

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