Polyacrylate polymer and synthesis method thereof

Abstract

The invention discloses a polyacrylate polymer and a synthesis method thereof, and relates to the technical field of polymer synthesis. According to the invention, specific types of lewis base and lewis acid are adopted, imino indole is used as the lewis base, the lewis base and the imino indole form an adduct or a hindered lewis acid-base pair under the synergy of the lewis acid, the adduct can be dissociated and form an active species under the action of a monomer, or the lewis base and the lewis acid form the hindered lewis acid-base pair. The organic nonmetal N / B Lewis acid-base pair provided by the invention is used for carrying out catalytic reaction, active controllable polymerization is realized in polymerization, the catalytic efficiency is high, and an acrylate copolymer can be efficiently obtained; reaction conditions are easy to meet, and the prepared polymer is high in molecular weight and narrow in molecular weight distribution; the synthesis method provided by the invention does not adopt metal ions, the cost is low, and the catalyst is easy to recover.

Description

Technical Field

[0001] The invention relates to the technical field of polymer synthesis, in particular to a polyacrylate polymer and a synthesis method thereof. Background Art

[0002] Polyacrylate polymers are a type of high molecular polymer synthesized from acrylic acid esters or methacrylic acid esters as the main raw materials. This type of polymer has good mechanical properties, weather resistance and acid and alkali resistance. At the same time, the copolymers of acrylic acid ester monomers also have good transparency, plasticity, weather resistance, good water resistance and chemical resistance. At present, the application of acrylic acid ester copolymers is very extensive, including packaging materials, building materials and textiles.

[0003] The physical properties of acrylate copolymers can be adjusted by adjusting the ratio of monomers and copolymerization conditions to obtain different properties. Since the concept of frustrated Lewis pair (FLP) was proposed by Stephan and Erker's research group, Lewis acid-base pair polymerization has developed rapidly in the past decade. Lewis acid-base pair polymerization technology has successfully achieved the active polymerization of a variety of acrylate monomers and improved the efficiency of the polymerization reaction. At the same time, the application of Lewis acid-base pair polymerization technology has also expanded to many cutting-edge fields such as biomedical materials, environmentally friendly materials, and smart response materials.

[0004] Although the synthesis of acrylic polymers catalyzed by Lewis acid-base pairs has many advantages, it still faces some challenges and problems in practical application: traditional Lewis acid-base pairs often rely on compounds containing metal ions, but such catalysts have problems such as high cost and difficulty in recycling. In addition, the commonly used non-metallic organic catalysts on the market are not very effective in promoting the copolymerization of acrylic monomers, such as catalytic efficiency, stability, polymer molecular weight and molecular weight distribution.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The object of the present invention is to provide a polyacrylate polymer and a synthesis method thereof, aiming to utilize a metal ion-free Lewis acid-base pair for catalysis and simultaneously obtain a polymer with high molecular weight and narrow molecular weight distribution.

[0007] The present invention is achieved in that:

[0008] In a first aspect, the present invention provides a method for synthesizing a polyacrylate polymer, comprising: using an acrylic ester monomer as a monomer raw material, and conducting conjugate addition polymerization under the catalytic action of a Lewis base and a Lewis acid;

[0009] The Lewis base is an iminoindole organic base, and its general structural formula satisfies at least one of the following:

[0010]

[0011] In the general formula of Lewis base, R 1 R is hydrogen, methyl, ethyl or isobutyl; 2 R is methyl, ethyl or isobutyl; 3 The radicals are hydrogen, methyl and ethyl; R 4 The radical is hydrogen or methyl;

[0012] Lewis acid is an organic boron with the following structural formula:

[0013]

[0014] The R group is ethyl, n-butyl, tert-butyl, cyclohexyl, phenyl or isopropoxy.

[0015] In an optional embodiment, the Lewis base is selected from at least one of the following compounds;

[0016]

[0017]

[0018]

[0019] Preferably, the Lewis base is selected from at least one of the following compounds:

[0020]

[0021] In an optional embodiment, the general formula of the acrylate monomer satisfies at least one of the following:

[0022]

[0023] In the general formula of acrylic acid ester monomers, R 1 is methyl, ethyl, n-butyl or aryl, R 2 is hydrogen or methyl, R 3 is methyl, ethyl, n-butyl, long-chain alkyl or aryl, R 4 is methyl;

[0024] Preferably, the acrylic acid ester monomer is selected from at least one of methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-phenoxyethyl methacrylate, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobornyl acrylate, 2-phenoxyethyl acrylate, isooctyl acrylate, isopentyl acrylate, 2-ethylethyl acrylate and 2-propylethyl acrylate.

[0025] In an optional embodiment, the molar ratio of the acrylic acid ester monomer, the Lewis acid and the Lewis base is (200-1000):n:1, wherein n=0.5-5.

[0026] In an optional embodiment, the method comprises: mixing an organic solvent, an acrylate monomer, a Lewis acid and a Lewis base to perform a polymerization reaction;

[0027] Preferably, the Lewis acid, the acrylate monomer and the organic solvent are first mixed, and then mixed with the Lewis base.

[0028] In an optional embodiment, the reaction temperature is controlled to be -20°C-60°C, and the reaction time is 0.5h-2h.

[0029] In an optional embodiment, the acrylic ester monomer includes a first monomer and a second monomer, the first monomer is a methacrylate monomer, and the second monomer is an acrylic ester monomer.

[0030] In an optional embodiment, the methacrylate monomer is selected from at least one of methyl methacrylate, ethyl methacrylate, n-butyl methacrylate and 2-phenoxyethyl methacrylate; more preferably methyl methacrylate;

[0031] Preferably, the acrylate monomer is selected from at least one of methyl acrylate, ethyl acrylate, n-butyl acrylate, isobornyl acrylate, 2-phenoxyethyl acrylate, isooctyl acrylate, isopentyl acrylate, 2-ethylethyl acrylate and 2-propylethyl acrylate; more preferably, at least one of methyl acrylate and 2-phenoxyethyl acrylate.

[0032] In an alternative embodiment, the organic solvent is a polar hydrocarbon solvent;

[0033] Preferably, the organic solvent is selected from at least one of aromatic hydrocarbons and alkanes; more preferably, the organic solvent is selected from at least one of methyl ethyl ketone, cyclohexanone, xylene, toluene, ethylbenzene, dichloromethane and tetrahydrofuran;

[0034] Preferably, the monomer concentration is adjusted to be 0.8 mol / L-4.8 mol / L by adjusting the amount of the organic solvent.

[0035] In a second aspect, the present invention provides a polyacrylate polymer prepared by the synthesis method of any one of the aforementioned embodiments;

[0036] Preferably, the molecular weight of the polyacrylate polymer is in the range of 17.6-197.7 kg / mol, and the molecular weight distribution PDI=1.02-1.11.

[0037] The present invention has the following beneficial effects: the present invention adopts a specific type of Lewis base and Lewis acid, and uses iminoindole as a Lewis base. Under the coordination of Lewis acid, the two form an adduct or a hindered Lewis acid-base pair. Under the action of the monomer, the adduct can be dissociated and form an active species, or the Lewis base and the Lewis acid form a hindered Lewis acid-base pair. The organic non-metallic N / B Lewis acid-base pair provided by the present invention is used for catalytic reaction, active controllable polymerization is achieved in polymerization, the catalytic efficiency is high, and acrylic acid ester copolymers can be obtained efficiently; the reaction conditions are easy to meet, and the prepared polymer has a high molecular weight and a narrow molecular weight distribution; the synthesis method provided by the present invention does not use metal ions, the cost is low, and the catalyst is easy to recover. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 Example 1 Table 1 by Et 3 The molecular weight of the polymer obtained by catalyzing MMA (M n ) and molecular weight distribution (PDI) and [MMA] 0 / [SL118] 0 Linear graph of

[0040] Figure 2 Example 1 Table 1 SL118 / Et 3 Overlay of polymer gel permeation chromatography of different equivalents of MMA in system B;

[0041] Figure 3 Example 1 Table 1 by Et 3 The molecular weight of the polymer obtained by catalyzing 1000 equivalents of MMA (M n ) and the linear relationship between conversion (η) and molecular weight distribution (PDI);

[0042] Figure 4 Example 2 Table 3 by Et 3 The molecular weight of the polymer obtained by catalyzing MA (M n ) and molecular weight distribution (PDI) and [MA] 0 / [SL118] 0 Linear graph of

[0043] Figure 5 Example 2 Table 3 SL118 / Et 3Overlay of polymer gel permeation chromatography of different equivalents of MA in system B;

[0044] Figure 6 Example 3 Table 3 by Et 3 The molecular weight of the polymer obtained by catalyzing PHEA (M n ) and molecular weight distribution (PDI) with [PHEA] 0 / [SL118] 0 Linear graph of

[0045] Figure 7 Example 3 Table 3 SL118 / Et 3 Overlay of polymer gel permeation chromatography of different equivalents of PHEA in system B;

[0046] Figure 8 is a gel permeation chromatogram overlay of the chain extension experiment of Example 4;

[0047] Fig. 9 is a gel permeation chromatogram of the triblock copolymerization experiment of Example 5;

[0048] Fig.10 This is the gel permeation chromatogram of the diblock copolymerization experiment of Example 6. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0050] The embodiment of the present invention provides a method for synthesizing a polyacrylate polymer, comprising: using an acrylate monomer as a monomer raw material, and performing conjugate addition polymerization under the catalytic action of a Lewis base and a Lewis acid. The present invention regulates the types of the Lewis base and the Lewis acid so that the Lewis acid and the Lewis base can play a better synergistic role and promote conjugate addition polymerization.

[0051] The following is a description of each raw material:

[0052] [Lewis base]

[0053] Lewis base is an iminoindole organic base, and its general structural formula satisfies at least one of the following:

[0054]

[0055] In the general formula of Lewis base, R 1 The radical is hydrogen, methyl, ethyl or isobutyl, R 1The group can be any one of the above groups; R 2 The group is methyl, ethyl or isobutyl, R 2 The group can be any one of the above groups; R 3 The radicals are hydrogen, methyl and ethyl, R 3 The group can be any one of the above groups; R 4 The radical is hydrogen or methyl, R 4 The group can be any of the above groups.

[0056] In a preferred embodiment, the Lewis base is selected from at least one of the following compounds;

[0057]

[0058]

[0059]

[0060] By optimizing the type of Lewis base, the synergistic effect with the Lewis acid can be better exerted, the polymerization reaction can be promoted more efficiently, and the obtained polymer has a higher molecular weight and a narrower molecular weight distribution.

[0061] In a more preferred embodiment, the Lewis base is selected from at least one of the following compounds:

[0062]

[0063] The Lewis base selected from the above two compounds (SL118 and SL119, respectively) has a more obvious synergistic effect with the Lewis acid, which can further increase the molecular weight of the polymer and make the molecular weight distribution of the polymer narrower.

[0064] [Lewis acid]

[0065] Lewis acid is an organic boron with the following structural formula:

[0066]

[0067] The R group is ethyl, n-butyl, tert-butyl, cyclohexyl, phenyl or isopropoxy, and the R group can be any one or more of the above groups.

[0068] [Acrylate Monomers]

[0069] Common monomers used to prepare polyacrylate polymers are all suitable for the preparation method provided in the embodiments of the present invention, and the monomers may be acrylate or methacrylate.

[0070] In some embodiments, the general formula of the acrylate monomer satisfies at least one of the following:

[0071]

[0072] In the general formula of acrylic acid ester monomers, R 1 is methyl, ethyl, n-butyl or aryl, R 1 The group can be any one of the above groups; R 2 is hydrogen or methyl, R 2 The group can be any one of the above groups; R 3 is methyl, ethyl, n-butyl, long-chain alkyl or aryl, R 3 The group can be any one of the above groups; R 4 is methyl;

[0073] In a preferred embodiment, the acrylate monomer is selected from at least one of methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-phenoxyethyl methacrylate, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobornyl acrylate, 2-phenoxyethyl acrylate, isooctyl acrylate, isopentyl acrylate, 2-ethylethyl acrylate and 2-propylethyl acrylate. The acrylate monomer is preferably any one or more of the above. The specific chemical formula is as follows:

[0074]

[0075] It should be noted that the above-mentioned acrylic acid ester monomers are all suitable for the synthesis method provided in the embodiments of the present invention. They can be efficiently polymerized under the catalysis of the specific types of Lewis acids and Lewis bases of the present invention to obtain polymer products with high molecular weight and narrow molecular weight distribution.

[0076] In a preferred embodiment, the acrylate monomer includes a first monomer and a second monomer, the first monomer is a methacrylate monomer, and the second monomer is an acrylate monomer. The present invention utilizes iminoindole as a Lewis base, and in the cooperation of Lewis acid, the two form an adduct or a hindered Lewis acid-base pair, and the adduct can be dissociated and form an active species under the action of the monomer, or the Lewis base and the Lewis acid form a hindered Lewis acid-base pair. The active species or hindered Lewis acid-base pair realizes active controllable polymerization during polymerization, and can also realize copolymerization (random copolymerization and block copolymerization) between different (alkyl) acrylic monomers, especially acrylates of the photocurable monomer type, thereby obtaining poly (alkyl) acrylates.

[0077] Furthermore, the methacrylate monomer is selected from at least one of methyl methacrylate, ethyl methacrylate, n-butyl methacrylate and 2-phenoxyethyl methacrylate, and the first monomer may be any one or more of the above, preferably methyl methacrylate.

[0078] Furthermore, the acrylate monomer is selected from at least one of methyl acrylate, ethyl acrylate, n-butyl acrylate, isobornyl acrylate, 2-phenoxyethyl acrylate, isooctyl acrylate, isopentyl acrylate, 2-ethylethyl acrylate and 2-propylethyl acrylate, and the second monomer can be any one or more of the above, preferably at least one of methyl acrylate and 2-phenoxyethyl acrylate.

[0079] By optimizing the types of the first monomer and the second monomer, the molecular weight of the synthesized polyacrylate polymer is made higher and the molecular weight distribution is narrower.

[0080] [Organic solvents]

[0081] The organic solvent may be a common solvent that can dissolve the (alkyl)acrylate, Lewis base, Lewis acid and the generated polymer.

[0082] In some embodiments, the organic solvent may be a polar hydrocarbon solvent that can better dissolve the (alkyl)acrylate, Lewis base, Lewis acid, and the resulting polymer.

[0083] In a preferred embodiment, the organic solvent is selected from at least one of aromatic hydrocarbons and alkanes. The organic solvent may be any one or more of the above, and all of them can dissolve the raw materials and the polymer product well.

[0084] Further preferably, the organic solvent is selected from at least one of methyl ethyl ketone, cyclohexanone, xylene, toluene, ethylbenzene, dichloromethane and tetrahydrofuran. The organic solvent is one or more of the above solvents which can fully dissolve (alkyl) acrylate, Lewis base, Lewis acid and the generated polymer.

[0085] [Reaction conditions]

[0086] The organic solvent, the acrylate monomer, the Lewis acid and the Lewis base are mixed for polymerization reaction. Preferably, the Lewis acid, the acrylate monomer and the organic solvent are mixed first, and then mixed with the Lewis base. The Lewis base is added later, which is more conducive to regulating the molecular weight and molecular weight distribution of the polymer.

[0087] In some embodiments, the molar ratio of the acrylate monomer, the Lewis acid and the Lewis base is (200-1000): n: 1, wherein n = 0.5-5. That is, the mass ratio of the acrylate monomer to the Lewis base may be 200: 1, 300: 1, 400: 1, 500: 1, 600: 1, 700: 1, 800: 1, 900: 1, 1000: 1, etc.; the mass ratio of the Lewis acid to the Lewis base may be 0.5: 1, 1.0: 1, 2.0: 1, 3.0: 1, 4.0: 1, 5.0: 1, etc.

[0088] Furthermore, by adjusting the amount of organic solvent, the monomer concentration can be 0.8 mol / L-4.8 mol / L, such as 0.8 mol / L, 1.0 mol / L, 2.0 mol / L, 3.0 mol / L, 4.0 mol / L, 4.8 mol / L, etc.

[0089] In some embodiments, the reaction temperature is controlled to be -20°C-60°C, such as -20°C, -10°C, -0°C, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, etc. The reaction time is 0.5h-2h, such as 0.5h, 1.0h, 1.5h, 2.0h, etc.

[0090] The embodiment of the present invention provides a polyacrylate polymer, which is prepared by the synthesis method provided by the embodiment of the present invention. The polyacrylate polymer has the advantages of large molecular weight and narrow molecular weight distribution.

[0091] The molecular weight of the polymer increases with the increase of the ratio of monomer to catalyst, so the system can achieve a polymer molecular weight in the range of 17.6-197.7 kg / mol, a monomer conversion rate greater than 99%, and a narrow molecular weight distribution (PDI=1.02-1.11).

[0092] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0093] Example 1

[0094] This embodiment provides a method for synthesizing a polyacrylate polymer. This embodiment is directed to the conjugated addition polymerization of methyl methacrylate (MMA), and the steps are as follows:

[0095] The polymerization reaction was carried out in a glove box (reaction temperature was 25°C, the same below). A certain amount of Lewis acid was weighed and placed in a 25mL reaction bottle. Methyl methacrylate (0.51mL, 4.8mmol) and a certain amount of methyl ethyl ketone (1mL) were measured. After the two were mixed for a certain period of time, Lewis base was quickly added through a gas-tight syringe under vigorous stirring, and the timing was started. After stirring for a period of time until the monomer was completely converted, the reaction bottle was transferred to a fume hood, a sample was taken to test the gas phase, and the time was recorded. A 5% HCl / methanol solution (the mass fraction of HCl in the methanol solution was 5%, the same below) was added to terminate the polymerization reaction. The supernatant was removed by filtration, the polymer was fully washed with methanol, and dried in a vacuum oven at 50°C to constant weight. The monomer conversion rate was measured by gas chromatograph, and the molecular weight (M n ) and molecular weight distribution (PDI) were measured by gel permeation chromatography.

[0096] Experimental Group 1: The results of MMA polymerization catalyzed by different Lewis acids and 1-(N-piperidinylethyl)-3-(2,6-diisopropylphenyl)imidoindole (SL118) are summarized in Table 1:

[0097] Table 1 SL118 as Lewis base

[0098]

[0099] In Table 1, Et 3 B represents triethylborane, n Bu 3 B represents tributylborane, Cy 3 B represents tricyclohexylborane, (O i Pr) 3 B represents triisopropyl borate. The molar ratio of Lewis acid:Lewis base is 2:1. Figure 1 Example 1 Table 1 by Et 3 The molecular weight of the polymer obtained by catalyzing MMA (M n ) and molecular weight distribution (PDI) and [MMA] 0 / [SL118] 0 Linear graph of Et 3 The combination of B and SL118 can further improve the conversion rate and make the molecular weight distribution narrower.

[0100] Experimental Group 2: The results of MMA polymerization catalyzed by 1-(N-piperidinylethyl)-3-(2,6-dimethylphenyl)iminoindole (SL119) are summarized in Table 2, where the molar ratio of Lewis acid to Lewis base is 2:1. 3 The gel permeation chromatogram overlay of the polymer obtained by catalysis of B and SL118 is shown in Figure 2 .

[0101] Table 2 Polymerization of MMA with SL119 using different Lewis acids

[0102]

[0103]

[0104] From Table 2, we can see that Et 3 The combination of B and SL119 can further improve the conversion rate and make the molecular weight distribution narrower.

[0105] In order to further verify that it is active polymerization, SL118 / Et 3 The molecular weight of the polymer obtained by catalyzing 1000 equivalents of MMA in system B (M n The linear relationship between conversion rate (η) and molecular weight distribution (PDI) is shown in the attached Figure 3 .

[0106] Example 2

[0107] This embodiment provides a method for synthesizing a polyacrylate polymer. This embodiment is directed to the conjugated addition polymerization of methyl acrylate (MA), and the steps are as follows:

[0108] The polymerization reaction was carried out in a glove box. A certain amount of Lewis acid was weighed and placed in a 25 mL reaction bottle. Methyl acrylate (0.43 mL, 4.8 mmol) and 1 mL of methyl ethyl ketone were measured. After the two were mixed for a certain period of time, Lewis base was quickly added through a gas-tight syringe under vigorous stirring, and the timing was started. After stirring for a period of time until the monomer was completely converted, the reaction bottle was transferred to a fume hood, a sample was taken to test the gas phase, and the time was recorded. A 5% HCl / methanol solution was added to terminate the polymerization reaction. The supernatant was removed by filtration, the polymer was fully washed with methanol, and dried in a vacuum oven at 50 ° C to constant weight. The monomer conversion rate was measured by gas chromatograph, and the molecular weight (M) of the obtained polymer was n ) and molecular weight distribution (PDI) were measured by gel permeation chromatography.

[0109] The results of the polymerization of MA catalyzed by using different Lewis acids with SL118 are summarized in Table 3, and the results of the polymerization of MA catalyzed by using SL119 are summarized in Table 4. In the table, the molar ratio of Lewis acid:Lewis base is 2:1. Molecular weight of PMA (M n ) and molecular weight distribution (PDI) and [MA] 0 / [SL118] 0 The linear graph of Figure 4 shown. Figure 5 Table 3SL118 / Et 3 Overlay of polymer gel permeation chromatography of different equivalents of MA in system B.

[0110] Table 3 SL118 catalytic polymerization of MA

[0111]

[0112] From Table 3, we can see that Et 3 The polymerization of MA by combining B with SL118 can further improve the conversion rate and make the molecular weight distribution narrower.

[0113] Table 4 Different Lewis acids combined with SL119 polymerized MA

[0114]

[0115] From Table 4, we can see that Et 3 The polymerization of MA by combining B with SL119 can further improve the conversion rate and make the molecular weight distribution narrower.

[0116] Example 3

[0117] This embodiment provides a method for synthesizing a polyacrylate polymer. This embodiment is directed to the conjugated addition polymerization of 2-phenoxyethyl acrylate (PHEA), and the steps are as follows:

[0118] The polymerization reaction was carried out in a glove box. A certain amount of Lewis acid was weighed and placed in a 25 mL reaction bottle. 2-phenoxyethyl acrylate (0.84 mL, 4.8 mmol) and a certain amount of methyl ethyl ketone were measured. After the two were mixed for a certain period of time, Lewis base was quickly added through a gas-tight syringe under vigorous stirring, and the timing was started. After stirring for a period of time until the monomer was completely converted, the reaction bottle was transferred to a fume hood, a sample was taken to test the gas phase, and the time was recorded. A 5% HCl / methanol solution was added to terminate the polymerization reaction. The supernatant was removed by filtration, the polymer was fully washed with methanol, and dried in a vacuum oven at 50 ° C to constant weight. The monomer conversion rate was measured by gas chromatograph, and the molecular weight (M) of the resulting polymer was n ) and molecular weight distribution (PDI) were measured by gel permeation chromatography.

[0119] The results of PHEA polymerization catalyzed by using different Lewis acids with SL118 are summarized in Table 5, and the results of PHEA polymerization catalyzed by using SL119 are summarized in Table 6, in which the molar ratio of Lewis acid:Lewis base=2:1. Figure 6 Example 3 Table 5 by Et 3 The molecular weight of the polymer obtained by catalyzing PHEA (M n ) and molecular weight distribution (PDI) with [PHEA] 0 / [SL118] 0 Linear graph of Et 3 The gel permeation chromatogram overlay of the polymer obtained by catalysis of B and SL118 is shown in the attached figure. Figure 7 .

[0120] Table 5 Polymerization of PHEA catalyzed by SL118 as Lewis base

[0121]

[0122] From Table 5, we can see that using Et 3 The polymerization of PHEA by B and SL118 can further improve the conversion rate and make the molecular weight distribution narrower.

[0123] Table 6 Polymerization of PHEA with different Lewis acids and SL119

[0124]

[0125] From Table 6, we can see that using Et3 The polymerization of PHEA by B and SL119 can further improve the conversion rate and have a narrower molecular weight distribution.

[0126] Example 4

[0127] This embodiment provides a method for synthesizing a polyacrylate polymer. This embodiment is directed to chain extension of MMA, and the steps are as follows:

[0128] The polymerization reaction was carried out in a glove box. First, 2.4 mg (0.024 mmol) of Et 3 B was measured into a 20 mL reaction bottle, followed by the addition of 0.25 mL (2.4 mmol) of MMA and 0.5 mL of methyl ethyl ketone as solvent. Under vigorous stirring, a Lewis base (Et 3 The molar ratio of B and Lewis base is 2:1), and the timing is started. After the monomer is completely converted, sampling is performed, and then the same amount of MMA (0.25mL, 2.4mmol) and an appropriate amount of methyl ethyl ketone are added, and this process is repeated several times. After all monomers are completely converted, the reaction bottle is taken out of the glove box, and 5% HCl / methanol solution is added to terminate the polymerization reaction. Subsequently, the polymer is filtered out, washed thoroughly with methanol, and finally dried in vacuo at 50°C to constant weight. The conversion rate of the monomer is determined by gas chromatograph, and the molecular weight (M n ) and their molecular weight distribution (PDI) were analyzed by gel permeation chromatography.

[0129] Using SL118 with Et 3 The results of chain extension experiments with system B are summarized in Table 7. The molecular weight of PMMA (M n ) and molecular weight distribution (PDI) and [MMA] 0 / [SL118] 0 For the linear graph, see , and for the related gel permeation chromatogram, see Figure 8 The chain extension experimental data show that the polymer chain ends in this catalytic polymerization system can maintain good activity.

[0130] Table 7 Chain extension experimental results of MMA polymerization

[0131]

[0132] In the table, 200MMA means adding 200 equivalents of MMA monomer; 200 / 200MMA means adding 200 equivalents of MMA monomer and then adding 200 equivalents of MMA monomer after a period of time; and so on. The amounts of other monomers are not specifically listed.

[0133] Example 5

[0134] This embodiment provides a method for synthesizing a polyacrylate polymer. This embodiment is directed to the copolymerization of methyl methacrylate (MMA) and methyl acrylate (MA), and the steps are as follows:

[0135] Take the preparation of poly(PMMA-b-PMA-b-PMMA) as an example:

[0136] The polymerization reaction was carried out in a glove box. 2.4 mg Et 3 B was placed in a 25 mL reaction bottle, MMA (0.51 mL, 4.8 mmol) and 1 mL of methyl ethyl ketone were measured, and the two were mixed for a certain period of time. Under vigorous stirring, Lewis base (Et 3 The molar ratio of B and Lewis base is 2:1), and the timing is started. After stirring for a period of time until the monomer is completely converted, the time is recorded and a sample is taken to test the gas phase. Then MA (0.43mL, 4.8mmol) and MMA (0.51mL, 4.8mmol) monomers are added. After a certain period of reaction until the monomer is completely converted, the reaction bottle is transferred to a fume hood, a sample is taken to test the gas phase, and the time is recorded. A 5% HCl / methanol solution is added to terminate the polymerization reaction. The supernatant is removed by filtration, the polymer is fully washed with methanol, and dried in a vacuum oven at 50°C to constant weight. The monomer conversion rate is measured by gas chromatograph, and the molecular weight (M) of the obtained homopolymer and copolymer is n ) and molecular weight distribution (PDI) were measured by gel permeation chromatography. The gel permeation chromatogram is shown in Fig. 9 . Use SL118 with Et 3 The results of the experiments on system B are summarized in Table 8.

[0137] Table 8 Copolymerization of MMA and MA

[0138]

[0139] Example 6

[0140] This embodiment provides a method for synthesizing a polyacrylate polymer. This embodiment is directed to the copolymerization of methyl methacrylate (MMA) and 2-phenoxyethyl acrylate (PHEA), and the steps are as follows:

[0141] Take the preparation of poly(PMMA-b-PPHEA) as an example:

[0142] The polymerization reaction was carried out in a glove box. 2.4 mg (0.024 mmol) of Et 3 B was placed in a 25 mL reaction bottle, MMA (0.51 mL, 4.8 mmol) and 1 mL of methyl ethyl ketone were measured, and the two were mixed for a certain period of time. Under vigorous stirring, Lewis base (Et 3The molar ratio of B and Lewis base is 2:1), and the timing is started. After stirring for a period of time until the monomer is completely converted, the time is recorded and a sample is taken to test the gas phase. Then PHEA (0.84mL, 4.8mmol) monomer is added. After a certain period of reaction until the monomer is completely converted, the reaction bottle is transferred to a fume hood, a sample is taken to test the gas phase, and the time is recorded. A 5% HCl / methanol solution is added to terminate the polymerization reaction. The supernatant is removed by filtration, the polymer is fully washed with methanol, and dried in a vacuum oven at 50°C to constant weight. The monomer conversion rate is measured by gas chromatograph, and the molecular weight (M) of the obtained homopolymer and copolymer is n ) and molecular weight distribution (PDI) were measured by gel permeation chromatography. The gel permeation chromatogram is shown in Fig.10 . Use SL118 with Et 3 The results of the experiments on system B are summarized in Table 9.

[0143] Table 9 Copolymerization of MMA and PHEA

[0144]

[0145] As can be seen from Table 9, the molecular weight distribution of the obtained polymer is narrow and the raw material conversion rate is very high.

[0146] Comparative Example 1

[0147] The only difference from the second group in Table 1 of Example 1 is that SL118 / 2Et 3 B was replaced by an equal amount of NHO-2:2AlCl 3 Data source: Jia Yinbao. Based on Al(C 6 F 5 ) 3 Hindered Lewis acid-base catalyzed polymerization of polar olefin monomers[D]. Dalian University of Technology, 2015.

[0148] Comparative Example 2

[0149] The only difference from the second group in Table 1 of Example 1 is that SL118 / 2Et 3 B is replaced by an equal amount of P(NI i Pr)Ph 2 / 2(BHT)Al i Bu 2 . Data source: Bai Yun. Hindered Lewis acid-base pairs based on novel phosphine bases catalyze the living polymerization of polar vinyl monomers[D]. Jilin University, 2021.

[0150] Comparative Example 3

[0151] The only difference from the second group in Table 1 of Example 1 is that SL118 / 2Et 3 B is replaced by an equal amount of HMPT / 2i Bu 3 Al.

[0152] Data source: Y.Cai, X.Zhao, B.Wang, W.Shi, F.Ge,

[0153] Comparative Example 4

[0154] The only difference from the first group in Table 1 of Example 1 is that Et 3 The molar ratio of B to the Lewis base is 1:1.

[0155] Comparative Example 5

[0156] The only difference from the first group in Table 1 of Example 1 is that Et 3 The molar ratio of B to Lewis base is 3:1.

[0157] Comparative Example 6

[0158] The only difference from the first group in Table 1 of Example 1 is that Et 3 The molar ratio of B to Lewis base is 4:1.

[0159] The specific data of comparative examples 1-6 are shown in the table below

[0160] Table 10 Data of polymerized MMA in comparative examples 1-6

[0161]

[0162] In summary, the present invention provides a polyacrylate polymer and a synthesis method thereof, and the synthesis method has the following advantages:

[0163] (1) Compared with the prior art, the raw materials of the system of the present invention are cheap and readily available (commercially available), easy to operate, mild and fast reaction conditions, high conversion rate (greater than 99%), and no metal ion doping.

[0164] (2) The present invention is a living controllable polymerization with high initiation efficiency, which can provide a polymer with controllable molecular weight, and the reaction is easy to operate industrially.

[0165] (3) The present invention can realize block copolymerization between different (alkyl) acrylate monomers, thereby greatly reducing the cost of obtaining (alkyl) acrylate polymers.

[0166] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for synthesizing a polyacrylate polymer, characterized in that: include: Using acrylic acid ester monomers as monomer raw materials, conjugate addition polymerization is carried out under the catalysis of Lewis base and Lewis acid; Wherein, the Lewis base is an iminoindole organic base, and its general structural formula satisfies at least one of the following: In the general formula of the Lewis base, the R1 group is hydrogen, methyl, ethyl or isobutyl; the R2 group is methyl, ethyl or isobutyl; the R3 group is hydrogen, methyl and ethyl; the R4 group is hydrogen or methyl; The Lewis acid is an organic boron with the following structural formula: The R group is ethyl, n-butyl, tert-butyl, cyclohexyl, phenyl or isopropoxy.

2. The synthesis method according to claim 1, characterized in that The Lewis base is selected from at least one of the following compounds; Preferably, the Lewis base is selected from at least one of the following compounds:

3. The synthesis method according to claim 1, characterized in that The general formula of the acrylic acid ester monomer satisfies at least one of the following: In the general formula of the acrylic acid ester monomer, R1 is methyl, ethyl, n-butyl or aryl, R2 is hydrogen or methyl, R3 is methyl, ethyl, n-butyl, long-chain alkyl or aryl, and R4 is methyl; Preferably, the acrylic acid ester monomer is selected from at least one of methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-phenoxyethyl methacrylate, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobornyl acrylate, 2-phenoxyethyl acrylate, isooctyl acrylate, isopentyl acrylate, 2-ethylethyl acrylate and 2-propylethyl acrylate.

4. The synthesis method according to any one of claims 1 to 3, characterized in that The molar ratio of the acrylic acid ester monomer, the Lewis acid and the Lewis base is (200-1000):n:1, wherein n=0.5-5.

5. The synthesis method according to claim 4, characterized in that include: Mixing an organic solvent, the acrylic ester monomer, the Lewis acid and the Lewis base to perform a polymerization reaction; Preferably, the Lewis acid, the acrylate monomer and the organic solvent are first mixed, and then mixed with the Lewis base.

6. The synthesis method according to claim 5, characterized in that The reaction temperature is controlled at -20°C-60°C and the reaction time is 0.5h-2h.

7. The synthesis method according to claim 5, characterized in that The acrylic ester monomer includes a first monomer and a second monomer, wherein the first monomer is a methacrylic ester monomer, and the second monomer is an acrylic ester monomer.

8. The synthesis method according to claim 7, characterized in that The methacrylate monomer is selected from at least one of methyl methacrylate, ethyl methacrylate, n-butyl methacrylate and 2-phenoxyethyl methacrylate; more preferably methyl methacrylate; Preferably, the acrylate monomer is selected from at least one of methyl acrylate, ethyl acrylate, n-butyl acrylate, isobornyl acrylate, 2-phenoxyethyl acrylate, isooctyl acrylate, isopentyl acrylate, 2-ethylethyl acrylate and 2-propylethyl acrylate; more preferably, at least one of methyl acrylate and 2-phenoxyethyl acrylate.

9. The synthesis method according to claim 5, characterized in that The organic solvent is a polar hydrocarbon solvent; Preferably, the organic solvent is selected from at least one of aromatic hydrocarbons and alkanes; more preferably, the organic solvent is selected from at least one of methyl ethyl ketone, cyclohexanone, xylene, toluene, ethylbenzene, dichloromethane and tetrahydrofuran; Preferably, the monomer concentration is adjusted to be 0.8 mol / L-4.8 mol / L by adjusting the amount of the organic solvent.

10. A polyacrylate polymer, characterized in that Prepared by the synthesis method according to any one of claims 1 to 9; Preferably, the molecular weight of the polyacrylate polymer is in the range of 17.6-197.7 kg / mol, and the molecular weight distribution PDI=1.02-1.11.

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