Asymmetric brush polymer and preparation method thereof
The one-pot synthesis of asymmetric brush polymers solves the problems of cumbersome steps and difficulty in controlling molecular weight in existing technologies, achieving the effects of simplified synthesis and cost reduction.
Patent Information
- Application Number
- CN202511917041.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-18
- Publication Date
- 2026-03-24
AI Technical Summary
The synthesis of asymmetric brush polymers in the prior art is complicated, requiring multiple purification processes, and the molecular weight and distribution of the polymer are difficult to control effectively.
Asymmetric brush polymers were synthesized using a one-pot method. The norbornene derivative was generated by reacting 5-norbornene-2-ex,3-ex-diethanol with 2-(dodecylthiocarbothio)propionic acid. Subsequently, the norbornene derivative was reacted with caprolactone and methyl acrylate in the presence of a ring-opening polymerization catalyst and a photocatalyst. Finally, the asymmetric macromonomer was synthesized under a Grubb catalyst.
The synthesis process was simplified, the number of reaction steps and purification times was reduced, production costs were lowered, and controllability of polymer molecular weight and distribution was achieved.
Smart Images
Figure CN121718002A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of polymer synthesis, and more specifically, to an asymmetric brush polymer and its preparation method. Background Technology
[0002] In the field of polymer chemistry, brush polymers refer to a class of macromolecules with numerous side chains densely grafted onto a linear backbone. These dense side chains endow them with various properties, such as a unique linear conformation, low viscosity, and minimal chain entanglement. Based on these properties, brush polymers have been widely used in biomedicine, elastomer materials, and chemical power sources. Asymmetric brush polymers are those with two or more different types of side chains on the repeating units of the backbone. These polymers possess various special properties and have been used in antifouling coatings, biomedicine, photonic crystals, and surfactants. Currently, the main factor limiting the large-scale application of asymmetric brush polymers is their overly complex synthetic design.
[0003] Currently, the synthesis technology of asymmetric brush polymers mainly involves the stepwise synthesis of macromonomers with two or more different blocks, followed by the polymerization of these macromonomers to synthesize the asymmetric brush polymer. Each step requires precise chemical manipulation and complex post-processing steps, such as multiple purification processes, to ensure the purity and quality of the final product. However, this stepwise synthesis method is not only cumbersome, requiring multiple purifications and wasting human and material resources, but also makes it difficult to effectively control the molecular weight and distribution of the polymer. These problems constitute urgent technical challenges to be solved in the field of asymmetric brush polymer synthesis.
[0004] There is currently no good solution to the above problems. Summary of the Invention
[0005] This application provides an asymmetric brush polymer and its preparation method, which at least solves the technical problems in the prior art of cumbersome synthesis steps for asymmetric brush polymers, requiring multiple purifications, and difficulty in effectively controlling the molecular weight and distribution of the polymer.
[0006] According to one aspect of the embodiments of this application, a method for preparing an asymmetric brush polymer is provided, the method comprising: step S1: reacting 5-norbornene-2-ex,3-ex-diethanol with 2-(dodecylthiocarbothio)propionic acid to obtain a norbornene derivative having both 2-(dodecylthiocarbothio)propyl ester and hydroxyl units; step S2: reacting the norbornene derivative with caprolactone and methyl acrylate in a light-irradiated reaction system in the presence of a ring-opening polymerization catalyst and a photocatalyst to obtain an asymmetric macromonomer containing both polymethyl acrylate and polycaprolactone block units; step S3: reacting the asymmetric macromonomer in the presence of a Grubb catalyst to obtain the asymmetric brush polymer.
[0007] Furthermore, in step S1, the reaction is carried out at a temperature of 0~25°C for 8~28 hours.
[0008] Furthermore, in step S2, the reaction is carried out at a temperature of 0~25°C for 0.5~3 hours.
[0009] Furthermore, in step S3, the reaction is carried out at a temperature of 0~25°C for 0.5~2.5 hours.
[0010] Further, in step S1, the reaction is carried out in the presence of a dehydrating agent and a catalyst, and the molar ratio of the dehydrating agent, the catalyst, 5-norbornene-2-ex,3-ex-diethanol and 2-(dodecylthiocarbothio)propionic acid is 1.5~2:0.5~0.6:1:1~1.5.
[0011] Further, in step S2, the molar ratio of norbornene derivative, caprolactone, and methyl acrylate is 1:10~50:10~50.
[0012] Further, in step S2, the molar ratio of the ring-opening polymerization catalyst to caprolactone is 1:40~50, and the molar ratio of methyl acrylate to photocatalyst is 1:1.0. 10 -5 ~2.0 10 -5 .
[0013] Furthermore, in step S2, the light irradiation reaction system is a blue light irradiation reaction system.
[0014] Furthermore, in step S2 and step S3, the molar ratio of the asymmetric macromonomer to the Grubb catalyst is 50-300:1.
[0015] According to another aspect of the embodiments of this application, an asymmetric brush polymer is also provided, which is prepared by the methods of various embodiments of this application.
[0016] In the method for preparing the asymmetric brush polymer provided in this application, a norbornene derivative with a chain transfer agent group (2-(dodecylthiocarbothio)propyl ester) and a hydroxyl group is first synthesized through a simple esterification reaction. The chain transfer agent group and hydroxyl group of the norbornene derivative can independently regulate the living radical polymerization of methyl acrylate and the cationic ring-opening polymerization of caprolactone. Using this norbornene derivative as the initiating unit, the cationic ring-opening polymerization of caprolactone is catalyzed by a ring-opening polymerization catalyst, and the photo-initiated controlled radical polymerization is catalyzed by a photocatalyst to prepare an asymmetric macromonomer (NB) with polycaprolactone (PCL) and polymethyl acrylate (PMA) units in a one-pot process. Simultaneous one-pot polymerization of multiple polymerization reactions greatly simplifies the synthesis process, reduces reaction steps and purification times, and lowers production costs. The polymerization of the asymmetric macromonomer is catalyzed by a Gerrabbe catalyst to prepare the asymmetric brush polymer. The Gerrabbe catalyst ensures that the molecular weight and distribution of the polymer are controllable, thus overcoming the problem of difficult molecular weight control in the prior art.
[0017] Typically, asymmetric brush polymers require three to four steps to prepare, while this method only requires two steps. This greatly simplifies the synthesis process of this type of polymer and reduces the loss of raw materials and solvents, which is beneficial for the large-scale application of this type of polymer. The highlight of this technology is that it simplifies the preparation process of asymmetric macromonomers, allowing the asymmetric macromonomers to be obtained in one step. Attached Figure Description
[0018] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:
[0019] Figure 1 This is a schematic diagram of the synthesis route for asymmetric brush polymers.
[0020] Figure 2 This is an atomic force microscope image of the asymmetric brush polymer synthesized in Example 1. Detailed Implementation
[0021] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.
[0022] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification, claims and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product or device.
[0023] As explained in the background section, the existing synthesis techniques for asymmetric brush polymers are not only cumbersome, requiring multiple purification processes and wasting manpower and resources, but also make it difficult to effectively control the molecular weight and distribution of the polymer. To address these problems, this application provides a method for preparing an asymmetric brush polymer, comprising: Step S1: reacting 5-norbornene-2-ex,3-ex-diethanol with 2-(dodecylthiocarbothio)propionic acid (DTPA) to obtain a norbornene derivative containing both 2-(dodecylthiocarbothio)propyl ester and hydroxyl units; Step S2: reacting the norbornene derivative with caprolactone and methyl acrylate in a light-irradiated reaction system in the presence of a ring-opening polymerization catalyst and a photocatalyst to obtain an asymmetric macromonomer containing both polymethyl acrylate and polycaprolactone block units; Step S3: reacting the asymmetric macromonomer in the presence of a Grubb catalyst to obtain the asymmetric brush polymer.
[0024] In the method for preparing the asymmetric brush polymer provided in this application, a norbornene derivative with a chain transfer agent group (2-(dodecylthiocarbothio)propyl ester) and a hydroxyl group is first synthesized through a simple esterification reaction. The chain transfer agent group and hydroxyl group of the norbornene derivative can independently regulate the living radical polymerization of methyl acrylate and the cationic ring-opening polymerization of caprolactone. Using this norbornene derivative as the initiating unit, the cationic ring-opening polymerization of caprolactone is catalyzed by a ring-opening polymerization catalyst, and the photo-initiated controlled radical polymerization is catalyzed by a photocatalyst to prepare an asymmetric macromonomer (NB) with polycaprolactone (PCL) and polymethyl acrylate (PMA) units in a one-pot process. Simultaneous one-pot polymerization of multiple polymerization reactions greatly simplifies the synthesis process, reduces reaction steps and purification times, and lowers production costs. The polymerization of the asymmetric macromonomer is catalyzed by a Gerrabbe catalyst to prepare the asymmetric brush polymer. The Gerrabbe catalyst ensures that the molecular weight and distribution of the polymer are controllable, thus overcoming the problem of difficult molecular weight control in the prior art.
[0025] Typically, asymmetric brush polymers require three to four steps to prepare, while this method only requires two steps. This greatly simplifies the synthesis process of this type of polymer and reduces the loss of raw materials and solvents, which is beneficial for the large-scale application of this type of polymer. The highlight of this technology is that it simplifies the preparation process of asymmetric macromonomers, allowing the asymmetric macromonomers to be obtained in one step.
[0026] Preferably, in steps S1-S3, the reaction can be carried out in a solvent. The solvent can dissolve the reactants, allowing them to disperse uniformly in the solution, promoting effective contact and reaction between the reactants, thereby contributing to better product purity and reaction selectivity. In steps S1 and S3, the solvent can be dichloromethane and chloroform; in step S2, the solvent can be toluene and chloroform, but is not limited to these. The choice of solvent is based on its ability to provide a suitable reaction environment, promoting efficient and stable bonding reactions between the reactants. Those skilled in the art can select appropriate solvents for the reactions in steps S1-S3 as needed.
[0027] Preferably, in step S1, the reaction can be carried out at a temperature of 0-25°C for 8-28 hours. By controlling the temperature and time of the esterification reaction in step S1, the selectivity of the reaction can be better ensured, thereby precisely controlling the molecular weight and distribution of the final asymmetric brush polymer, avoiding side reactions that may be caused by high temperature or long reaction time, further reducing the waste of raw materials, and thus further improving the purity and yield of the product. Preferably, in step S1, the reaction temperature can be 0-10°C; the reaction time can be 12-18 hours.
[0028] Preferably, in step S2, the reaction can be carried out at a temperature of 0-25°C for 0.5-3 hours. By controlling the temperature and time of the reaction in step S2, the living radical polymerization of methyl acrylate and the cationic ring-opening polymerization of caprolactone can proceed more fully without over-polymerization, thereby better maintaining the structural integrity of the block polymer and saving purification steps. Preferably, in step S2, the reaction temperature can be 0-5°C; the reaction time can be 1-2 hours.
[0029] Preferably, in step S3, the reaction can be carried out at a temperature of 0~25°C for 0.5~2.5 hours. By controlling the temperature and time of the reaction in step S3, not only can energy consumption be better reduced, but side effects such as thermal decomposition and oxidation can also be effectively suppressed, allowing for better polymerization of asymmetric macromonomers, thereby better ensuring the quality and yield of the product. Preferably, in step S3, the reaction time can be 0.5~1 hour.
[0030] Preferably, in step S1, the reaction is carried out in the presence of a dehydrating agent and a catalyst, and the molar ratio of the dehydrating agent, catalyst, 5-norbornen-2-ex,3-ex-diethanol, and 2-(dodecylthiocarbothio)propionic acid can be 1.5~2:0.5~0.6:1:1~1.5. Precise control of the molar ratio of the dehydrating agent, catalyst, 5-norbornen-2-ex,3-ex-diethanol, and 2-(dodecylthiocarbothio)propionic acid further contributes to improving the purity of the product, thereby reducing subsequent processing steps.
[0031] Preferably, the dehydrating agent can be dicyclohexylcarbodiimide (DCC), and the catalyst can be 4-dimethylaminopyridine (DMAP).
[0032] Preferably, in step S2, the molar ratio of norbornene derivative, caprolactone, and methyl acrylate can be 1:10~50:10~50. Precise control of the molar ratio of norbornene derivative, caprolactone, and methyl acrylate further optimizes the design of the macromonomer, allowing the number and length of polycaprolactone and polymethyl acrylate block units to be flexibly adjusted according to actual needs. This further helps to control the length and number of polycaprolactone and polymethyl acrylate units in the asymmetric macromonomer, thereby precisely controlling the molecular weight and distribution of the final asymmetric brush polymer.
[0033] Preferably, in step S2, the molar ratio of the ring-opening polymerization catalyst to caprolactone can be 1:40~50, and the molar ratio of methyl acrylate to photocatalyst is 1:1.0. 10 -5 ~2.0 10 -5 Adjusting the molar ratio of ring-opening polymerization catalyst to caprolactone and the molar ratio of methyl acrylate to photocatalyst enables the synthesis of asymmetric macromonomers with higher efficiency and selectivity. Furthermore, it allows for the one-pot synthesis of highly ordered asymmetric macromonomers with complex structures under relatively mild conditions.
[0034] Preferably, in step S2, the ring-opening polymerization catalyst can be diphenyl phosphate, and the photocatalyst can be tris(2-phenylpyridine)iridium.
[0035] Preferably, in step S2, the light irradiation reaction system is a blue light irradiation reaction system. Preferably, the blue light can have a maximum wavelength of 420 nm and a wavelength of 2 mW / cm². 2 The power of the reaction system can be increased by using blue light to synthesize asymmetric macromonomers with higher efficiency and selectivity in step S2.
[0036] Preferably, in step S3, the molar ratio of the asymmetric macromonomer to the Grubb catalyst can be 50-300:1. Appropriate control of the Grubb catalyst dosage can better ensure the high efficiency of the polymerization reaction while better avoiding the impact of catalyst residue on the final product performance. It allows for more precise control of the polymer's molecular structure, enabling the large-scale preparation of high-performance asymmetric brush polymers. The Grubb catalyst can be a third-generation Grubb catalyst. Third-generation Grubb catalysts initiate polymerization extremely quickly and can achieve precise control of molecular weight and polymer unit distribution. Moreover, this catalyst has high activity and low dosage, which can further reduce the amount of solvent used, thereby reducing post-processing steps and making it more suitable for industrial production.
[0037] According to another aspect of the embodiments of this application, an asymmetric brush polymer is also provided, which is prepared by the methods of various embodiments of this application.
[0038] In the asymmetric brush polymer prepared by the method provided in this application embodiment, the molecular weight and distribution of the polymer can be effectively controlled.
[0039] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.
[0040] Example
[0041] Preparation of asymmetric brush polymers
[0042] Example 1
[0043] Step S1: 5g of 5-norbornene-2-ex,3-ex-diethanol and 11g of 2-(dodecylthiocarbonthio)propionic acid were placed in 0.5L of dichloromethane solvent and stirred. 3g of DCC and 1.4g of DMAP were added, and the mixture was reacted at 0℃ for 12h to obtain 12g of norbornene derivative containing both 2-(dodecylthiocarbonthio)propionate and hydroxyl units.
[0044] Step S2: Add 200 mg of norbornene derivative, 1.7 g of caprolactone, 40 mg of diphenyl phosphate, 1.3 g of methyl acrylate, and 0.8 mg of tris(2-phenylpyridine)iridium to 0.5 mL of toluene. Irradiate the reaction system with blue light at a maximum wavelength of 430 nm at 0 °C for 1 h to obtain 2.1 g of asymmetric macromonomer (NB1) containing both polymethyl acrylate (PMA) and polycaprolactone (PCL) block units.
[0045] Step S3: Mix 1g of macromonomer with 30mg of third-generation Grubb catalyst and dissolve in 2mL of dichloromethane solvent. React at 0℃ for 0.5h to obtain an asymmetric brush polymer.
[0046] Example 2
[0047] Step S1: 5g of 5-norbornene-2-ex,3-ex-diethanol and 11g of 2-(dodecylthiocarbonthio)propionic acid were placed in 0.5L of dichloromethane solvent and stirred. 3g of DCC and 1.4g of DMAP were added, and the mixture was reacted at 5°C for 12h to obtain 12g of norbornene derivative containing both 2-(dodecylthiocarbonthio)propionate and hydroxyl units.
[0048] Step S2: Add 200 mg of norbornene derivative, 1.7 g of caprolactone, 40 mg of diphenyl phosphate, 1.3 g of methyl acrylate, and 0.8 mg of tris(2-phenylpyridine)iridium to 0.5 mL of toluene. Irradiate the reaction system with blue light at a maximum wavelength of 430 nm at 5 °C for 1 h to obtain 2.1 g of asymmetric macromonomer (NB2) containing both polymethyl acrylate (PMA) and polycaprolactone (PCL) block units.
[0049] Step S3: Mix 1g of macromonomer with 30mg of third-generation Grubb catalyst and dissolve in 2mL of dichloromethane solvent. React at 3℃ for 0.5h to obtain an asymmetric brush polymer.
[0050] Example 3
[0051] Step S1: 5g of 5-norbornene-2-ex,3-ex-diethanol and 11g of 2-(dodecylthiocarbonthio)propionic acid were placed in 0.5L of dichloromethane solvent and stirred. 3g of DCC and 1.4g of DMAP were added, and the mixture was reacted at 0℃ for 18h to obtain 12g of norbornene derivative containing both 2-(dodecylthiocarbonthio)propionate and hydroxyl units.
[0052] Step S2: Add 200 mg of norbornene derivative, 1.7 g of caprolactone, 40 mg of diphenyl phosphate, 1.3 g of methyl acrylate, and 0.8 mg of tris(2-phenylpyridine)iridium to 0.5 mL of toluene. Irradiate the reaction system with blue light at a maximum wavelength of 430 nm at 0 °C for 2 h to obtain 2.1 g of asymmetric macromonomer (NB3) containing both polymethyl acrylate (PMA) and polycaprolactone (PCL) block units.
[0053] Step S3: Mix 1g of macromonomer with 30mg of third-generation Grubb catalyst and dissolve in 2mL of dichloromethane solvent. React at 0℃ for 1h to obtain an asymmetric brush polymer.
[0054] Example 4
[0055] Step S1: 5g of 5-norbornene-2-ex,3-ex-diethanol and 11g of 2-(dodecylthiocarbothio)propionic acid were placed in 0.5L of dichloromethane solvent and stirred. 3g of DCC and 1.4g of DMAP were added, and the mixture was reacted at 10°C for 18h to obtain 12g of norbornene derivative containing both 2-(dodecylthiocarbothio)propionate and hydroxyl units.
[0056] Step S2: Add 200 mg of norbornene derivative, 1.7 g of caprolactone, 40 mg of diphenyl phosphate, 1.3 g of methyl acrylate, and 0.8 mg of tris(2-phenylpyridine)iridium to 0.5 mL of toluene. Irradiate the reaction system with blue light at a maximum wavelength of 430 nm at 5 °C for 2 h to obtain 2.1 g of asymmetric macromonomer (NB4) containing both polymethyl acrylate (PMA) and polycaprolactone (PCL) block units.
[0057] Step S3: Mix 1g of macromonomer with 30mg of third-generation Grubb catalyst and dissolve in 2mL of dichloromethane solvent. React at 25°C for 1h to obtain an asymmetric brush polymer.
[0058] Example 5
[0059] Step S1: 6g of 5-norbornene-2-ex,3-ex-diethanol and 12g of 2-(dodecylthiocarbothio)propionic acid were placed in 0.8L of dichloromethane solvent and stirred. 5g of DCC and 2g of DMAP were added, and the mixture was reacted at 10°C for 18h to obtain 13.5g of norbornene derivative containing both 2-(dodecylthiocarbothio)propionate and hydroxyl units.
[0060] Step S2: Add 300 mg of norbornene derivative, 2.5 g of caprolactone, 49 mg of diphenyl phosphate, 1.7 g of methyl acrylate, and 1 mg of tris(2-phenylpyridine)iridium to 0.8 mL of toluene. Irradiate the reaction system with blue light at a maximum wavelength of 430 nm at 5 °C for 2 h to obtain 2.8 g of asymmetric macromonomer (NB5) containing both polymethyl acrylate (PMA) and polycaprolactone (PCL) block units.
[0061] Step S3: Mix 2g of macromonomer with 35mg of third-generation Grubb catalyst and dissolve in 3mL of dichloromethane solvent. React at 25℃ for 1h to obtain asymmetric brush polymer.
[0062] Example 6
[0063] Step S1: 5g of 5-norbornene-2-ex,3-ex-diethanol and 11g of 2-(dodecylthiocarbothio)propionic acid were placed in 0.5L of dichloromethane solvent and stirred. 3g of DCC and 1.4g of DMAP were added, and the mixture was reacted at 20°C for 4h to obtain 6g of norbornene derivative containing both 2-(dodecylthiocarbothio)propionate and hydroxyl units.
[0064] Step S2: Add 200 mg of norbornene derivative, 1.7 g of caprolactone, 40 mg of diphenyl phosphate, 1.3 g of methyl acrylate, and 0.8 mg of tris(2-phenylpyridine)iridium to 0.5 mL of toluene. Irradiate the reaction system with blue light at a maximum wavelength of 430 nm at 25 °C for 3 h to obtain 2.9 g of asymmetric macromonomer (NB6) containing both polymethyl acrylate (PMA) and polycaprolactone (PCL) block units.
[0065] Step S3: Mix 1g of macromonomer with 30mg of third-generation Grubb catalyst and dissolve in 2mL of dichloromethane solvent. React at 35℃ for 2h to obtain an asymmetric brush polymer.
[0066] Figure 1 This is a roadmap for the synthesis of asymmetric brush polymers, where m = 10~50, n = 10~50, and x = 50~300. These values can be controlled by the proportions used during material feeding. Figure 2 This is an atomic force microscope image of the asymmetric brush polymer (white strip) synthesized in Example 1. The height of the white strip is about 1~2 nm, which corresponds to the height of the monolayer. The length and width of the white strip correspond to the length and width of the asymmetric brush polymer. Figure 2 This demonstrates the successful preparation of the asymmetric brush polymer in Example 1.
[0067] The only difference between Example 2 and Example 1 is the increased reaction temperature in steps S1-S3. Similar to Example 1, Example 2 also successfully prepared an asymmetric brush polymer.
[0068] The only difference between Example 3 and Example 1 is the increased reaction time in steps S1-S3. Similar to Example 1, Example 3 also successfully prepared an asymmetric brush polymer.
[0069] Example 4 differs from Example 3 only in that the reaction temperature is increased in steps S1-S3. Similar to Example 3, Example 4 also successfully prepared an asymmetric brush polymer.
[0070] Example 5 differs from Example 4 only in the amount of reactants in steps S1-S3. Similar to Example 4, Example 5 also successfully prepared an asymmetric brush polymer.
[0071] Compared to Example 4, Example 6 differs only in the following ways: 1) The reaction time in step S1 is shorter and the temperature is higher, which reduces the product yield in step S1; 2) The reaction temperature in step S2 is higher and the reaction time is longer, which increases the product yield, but the polymer molecular weight is not as well controlled as in Example 4; 3) The reaction temperature in step S3 is higher and the reaction time is longer, which causes some side reactions, resulting in partial cross-linking of the polymer and precipitation. However, Example 6 also successfully prepared an asymmetric brush polymer, but the polymer molecular weight control was not as good as in Example 4, and byproducts were present.
[0072] The above embodiments of the present invention achieve the following technical effects:
[0073] In the method for preparing the asymmetric brush polymer provided in this application, a norbornene derivative with a chain transfer agent group (2-(dodecylthiocarbothio)propyl ester) and a hydroxyl group is first synthesized through a simple esterification reaction. The chain transfer agent group and hydroxyl group of the norbornene derivative can independently regulate the living radical polymerization of methyl acrylate and the cationic ring-opening polymerization of caprolactone. Using this norbornene derivative as the initiating unit, the cationic ring-opening polymerization of caprolactone is catalyzed by a ring-opening polymerization catalyst, and the photo-initiated controlled radical polymerization is catalyzed by a photocatalyst to prepare an asymmetric macromonomer (NB) with polycaprolactone (PCL) and polymethyl acrylate (PMA) units in a one-pot process. Simultaneous one-pot polymerization of multiple polymerization reactions greatly simplifies the synthesis process, reduces reaction steps and purification times, and lowers production costs. The polymerization of the asymmetric macromonomer is catalyzed by a Gerrabbe catalyst to prepare the asymmetric brush polymer. The Gerrabbe catalyst ensures that the molecular weight and distribution of the polymer are controllable, thus overcoming the problem of difficult molecular weight control in the prior art.
[0074] Typically, asymmetric brush polymers require three to four steps to prepare, while this method only requires two steps. This greatly simplifies the synthesis process of this type of polymer and reduces the loss of raw materials and solvents, which is beneficial for the large-scale application of this type of polymer. The highlight of this technology is that it simplifies the preparation process of asymmetric macromonomers, allowing the asymmetric macromonomers to be obtained in one step.
[0075] The asymmetric brush-type polymer prepared by the method of this application has an asymmetric structure, which can be adsorbed on the surface to form an ultra-dense structure. It is expected to play an important role in automotive paint clear coat anti-fouling coatings, superhydrophobic self-cleaning coatings, and self-healing coatings. This efficient synthesis method of this application is expected to promote the application of such polymers in the automotive industry and even more industries.
[0076] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.
Claims
1. A method for preparing an asymmetric brush-type polymer, characterized in that, include: Step S1: React 5-norbornene-2-ex,3-ex-diethanol with 2-(dodecylthiocarbothio)propionic acid to obtain a norbornene derivative having both 2-(dodecylthiocarbothio)propionate and hydroxyl units. Step S2: The norbornene derivative is reacted with caprolactone and methyl acrylate in the presence of a ring-opening polymerization catalyst and a photocatalyst using a light irradiation reaction system to obtain an asymmetric macromonomer containing both polymethyl acrylate and polycaprolactone block units. Step S3: React the asymmetric macromonomer in the presence of a Grubb catalyst to obtain an asymmetric brush polymer.
2. The method according to claim 1, characterized in that, In step S1, the reaction is carried out at a temperature of 0~25°C for 8~28 hours.
3. The method according to claim 1 or 2, characterized in that, In step S2, the reaction is carried out at a temperature of 0~25°C for 0.5~3 hours.
4. The method according to claim 1 or 2, characterized in that, In step S3, the reaction is carried out at a temperature of 0~25°C for 0.5~2.5 hours.
5. The method according to claim 1 or 2, characterized in that, In step S1, the reaction is carried out in the presence of a dehydrating agent and a catalyst, and the molar ratio of the dehydrating agent, the catalyst, 5-norbornene-2-ex,3-ex-diethanol and 2-(dodecylthiocarbothio)propionic acid is 1.5~2:0.5~0.6:1:1~1.
5.
6. The method according to claim 1 or 2, characterized in that, In step S2, the molar ratio of norbornene derivative, caprolactone, and methyl acrylate is 1:10~50:10~50.
7. The method according to claim 1 or 2, characterized in that, In step S2, the molar ratio of the ring-opening polymerization catalyst to caprolactone is 1:40~50, and the molar ratio of methyl acrylate to the photocatalyst is 1:1.
0. 10 -5 ~2.0 10 -5 .
8. The method according to claim 1 or 2, characterized in that, In step S2, the light irradiation reaction system is a blue light irradiation reaction system.
9. The method according to claim 1 or 2, characterized in that, In step S3, the molar ratio of the asymmetric macromolecular monomer to the Grubb catalyst is 50-300:
1.
10. An asymmetric brush-type polymer, characterized in that, Prepared by the method of any one of claims 1-9.