Synthesis method of phosphorus-containing block polymer

Abstract

The invention relates to a synthesis method of a phosphorus-containing block polymer, and belongs to the technical field of polymer preparation. A micro-channel continuous flow process is adopted, mixing and temperature control are enhanced, mixing is more uniform, and block polymers with different proportions can be synthesized by controlling the material proportion; the polymerization degree and molecular weight distribution of the block polymer can be controlled through the temperature and the polymerization time in the microchannel system, the molecular weight distribution is narrow, and the size of the molecular weight can be controlled.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer preparation and relates to a method for synthesizing a phosphorus-containing block polymer. Background Art

[0002] In the field of materials science, phosphorus-containing block polymers have received extensive attention and research due to their unique physical and chemical properties and potential application values. Such polymers usually have excellent flame retardancy, thermal stability, and specific functionality, showing great application potential in multiple fields such as flame retardant materials, electronic materials, and biomedical materials.

[0003] Traditionally, the synthesis of phosphorus-containing block polymers mostly uses an organic solvent system, which not only pollutes the environment but also requires complex solvent recovery steps in subsequent processing, increasing production costs. Although some methods for synthesizing phosphorus-containing block polymers in an aqueous phase have been reported, these methods often have problems such as harsh synthesis conditions, wide molecular weight distribution of products, and low yields. Therefore, it is still of great significance to develop a method for synthesizing phosphorus-containing block polymers with mild conditions, simple operation, and excellent product performance.

[0004] Patent 201980082709.1 discloses the polymerization of two groups of content monomers, controlling the exothermic reaction by dropping, etc., to avoid thermal runaway, but the method is still a batch reaction; in the paper "Method for polymerizing dimethyl vinylphosphonate and then hydrolyzing" by Dey R E et al., it is disclosed that by polymerizing dimethyl vinylphosphonate, the polymerization regularity is adjusted, but the hydrolysis process is added, and the process is cumbersome. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for synthesizing a phosphorus-containing block polymer, which has the characteristics of a moderate molecular weight and a narrow distribution of the obtained polymer.

[0006] The purpose of the present invention can be achieved by the following technical solutions: A method for synthesizing a phosphorus-containing block polymer, wherein the polymer is synthesized from a first polymerization monomer and a second polymerization monomer through an initiator using water as a solvent. Among them, the general formula of the first polymerization monomer is as follows: , R1 is H or a saturated alkyl group with 1 to 10 carbon atoms; The general formula of the second polymerization monomer is as follows: , wherein R2 is H or a saturated alkyl group, and R3 is one of H, an alkyl substituent, an alkyl substituent with a hydroxyl group, and a polymerizable acrylate monomer containing 1 to 10 polyether structural units; The specific process of the synthesis is as follows: S1: Mix the first polymerization monomer and the second polymerization monomer to obtain a mixed solution A, and place it in the first raw material bottle; S2: Dissolve the initiator in deionized water to obtain a solution B of the initiator, and place it in the second raw material bottle; S3: Feed the mixed solution A and the mixed solution B into a premixer for premixing, and simultaneously heat up to 60-90 °C to obtain a mixed solution C; S4: Feed the mixed solution C into a reaction tube, carry out the reaction at 60-90 °C, the reaction duration is 1-4 min, and after the reaction is completed, it enters the collection bottle through the outlet to complete the synthesis of the phosphorus-containing block polymer.

[0007] Furthermore, the molar ratio of the first polymerization monomer to the second polymerization monomer in S1 is (0.1-10):1.

[0008] Furthermore, the initiator in S2 is potassium persulfate, ammonium persulfate, 2,2'-azobis(2-methylpropionamidine) dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane] disulfate dihydrate, 2,2'-azobis[2-(2-imidazolin-2-yl)propane], 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] n and one or more of 4,4'-azobis(4-cyanovaleric acid sodium).

[0009] Furthermore, the mass ratio of the initiator to deionized water in S2 is (0.01-0.03):1, and the mass of the initiator is 1-5% of the mass of the phosphorus-containing monomer.

[0010] Furthermore, the weight-average molecular weight range of the phosphorus-containing block polymer prepared in S4 is 15,000-90,000.

[0011] In the traditional preparation process of phosphorus-containing polymers, due to the lower reaction activity of phosphorus-containing monomers compared with non-phosphorus polymerization monomers, more head-to-head or tail-to-tail structural units are likely to be generated in the polymer, the oligomer content is high, the molecular configuration regularity of the polymer is poor, and there is a large difference in thermal stability compared with polymers with better regularity; existing processes mostly use batch reactions, and due to the difference in the reaction activity of polymerization monomers, the polymerization is uneven, oligomers are easily generated, and the molecular configuration regularity is poor.

[0012] The beneficial effects of the present invention: The present invention adopts the microchannel continuous flow technology, in which the premixer adopts a microchannel structure. Therefore, by utilizing the laminar flow effect and diffusion mixing principle of the micron-scale channels, the mixed solution A and solution B are quickly and uniformly mixed. The reaction tube is a microreactor, that is, a microchannel reactor. The polymerization monomer and initiator are quickly and uniformly mixed by the microreactor, eliminating the local concentration difference, and the polymerization reaction starts synchronously, avoiding the phenomenon of asynchronous chain growth caused by mixing delay in the traditional reactor, thereby reducing the chain length difference and realizing the effective control of the molecular weight distribution. During the reaction process, mixing and polymerization are carried out under continuous conditions, improving the batch stability of the product.

[0013] In the present invention, the entire synthesis process from mixing monomers, dissolving initiators, premixing to reaction collection is clear and efficient, which is conducive to industrial production. And both the premixing and reaction stages are carried out at 60~90°C. The precise temperature control is conducive to the smooth progress of the reaction and the quality control of the product. The reaction duration is 1~4 minutes, greatly shortening the production cycle and improving the production efficiency.

[0014] The present invention optimizes the synthesis conditions by precisely controlling the reaction temperature and duration, making the reaction more efficient and the product performance more stable. Compared with the prior art, this precise parameter control may be unprecedented, providing new ideas and methods for the synthesis of phosphorus-containing block copolymers.

[0015] Moreover, the present invention has universality and can be applied to various types of polymerization monomers and initiators, providing the possibility for the development of new phosphorus-containing block copolymers.

[0016] The water-soluble phosphorus-containing copolymer prepared by the present invention can be used as a polymer electrolyte material for fuel cells, a halogen-free flame retardant, a metal surface treatment agent, a biocompatible material, a food packaging material, etc., and can also be used for metal surface treatment. In particular, the water-soluble phosphorus-containing copolymer prepared by the present invention can be used for the surface treatment of aluminum, forming a single molecular layer, improving the adhesion and salt spray resistance of powder coatings.

[0017] The present invention adopts the microchannel continuous flow process, strengthens mixing and temperature control, and the mixing is more uniform. Different proportion block copolymers can be synthesized by controlling the material ratio. The degree of polymerization and molecular weight distribution of the block copolymer can be controlled by the temperature and polymerization time in the microchannel system, and the molecular weight distribution is narrow and the size can be controlled. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] For the convenience of those skilled in the art to understand, the present invention will be further described below with reference to the accompanying drawings.

[0019] Figure 1 Reaction flow chart of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following, in conjunction with the attached drawings and preferred embodiments, details the specific implementation manners, structures, features and their effects according to the present invention as follows.

[0021] Example 1 S1: Mix 368 g of vinylphosphonic acid with 144 g of acrylic acid to obtain a mixed solution A, and place it in the first raw material bottle; S2: Dissolve 8.1 g of 2,2 - azobis(2 - methylpropionamidine) dihydrochloride in 280 g of deionized water to obtain a solution B of the polymerization initiator, and place it in the second raw material bottle; S3: Feed the mixed solution A and the mixed solution B into a premixer for premixing, and simultaneously raise the temperature to 60 °C to obtain a mixed solution C; S4: Feed the mixed solution C into a reaction tube, carry out the reaction at 60 °C, with a reaction duration of 1 min. After the reaction is completed, it enters the collection bottle through the outlet to complete the synthesis of the phosphorus - containing block polymer.

[0022] In this example, the conversion rate of the acrylic acid monomer is 99.47%, the weight - average relative molecular mass Mw is 16243, and the polydispersity is 1.87.

[0023] Example 2 S1: Mix 184 g of vinylphosphonic acid with 301 g of methacrylic acid to obtain a mixed solution A, and place it in the first raw material bottle; S2: Dissolve 4.2 g of 4,4 - azobis(4 - cyanovaleric acid sodium) in 384 g of deionized water to obtain a solution B of the initiator, and place it in the second raw material bottle; S3: Feed the mixed solution A and the mixed solution B into a premixer for premixing, and simultaneously raise the temperature to 70 °C to obtain a mixed solution C; S4: Feed the mixed solution C into a reaction tube, carry out the reaction at 70 °C, with a reaction duration of 4 min. After the reaction is completed, it enters the collection bottle through the outlet to complete the synthesis of the phosphorus - containing block polymer.

[0024] In this example, the conversion rate of the methacrylic acid monomer is 99.25%, the weight - average relative molecular mass Mw is 78722, and the polydispersity is 2.3.

[0025] Example 3: S1: Mix 184 g of vinylphosphonic acid with 122.7 g of acrylic acid to obtain a mixed solution A, and place it in the first raw material bottle; S2: Dissolve 4.0 g of potassium persulfate in 384 g of deionized water to obtain a solution B of the initiator, and place it in the second raw material bottle; S3: Feed the mixed solution A and the mixed solution B into a premixer for premixing, and simultaneously raise the temperature to 80 °C to obtain a mixed solution C; S4: Feed the mixed solution C into the reaction tube, carry out the reaction at 80 °C for 4 min, and after the reaction is completed, it enters the collection bottle through the outlet to complete the synthesis of the phosphorus-containing block polymer.

[0026] In this example, the conversion rate of acrylic acid monomer is 99.10%, the weight-average relative molecular mass Mw is 61281, and the polydispersity is 2.0.

[0027] Example 4: S1: Mix 184 g of dimethyl vinylphosphonate with 122.7 g of acrylic acid to obtain a mixed solution A, and place it in the first raw material bottle; S2: Dissolve 4.0 g of potassium persulfate in 384 g of deionized water to obtain an initiator solution B, and place it in the second raw material bottle; S3: Feed the mixed solution A and the mixed solution B into a premixer for premixing, and at the same time raise the temperature to 80 °C to obtain a mixed solution C; S4: Feed the mixed solution C into the reaction tube, carry out the reaction at 80 °C for 4 min, and after the reaction is completed, it enters the collection bottle through the outlet to complete the synthesis of the phosphorus-containing block polymer.

[0028] In this example, the conversion rate of acrylic acid monomer is 99.30%, the weight-average relative molecular mass Mw is 62170, and the polydispersity is 2.1.

[0029] Example 5: S1: Mix 184 g of vinylphosphonic acid with 1666 g of 2-hydroxyethyl methacrylate to obtain a mixed solution A, and place it in the first raw material bottle; S2: Dissolve 9.2 g of 2,2'-azobis(2-methylpropionamidine) dihydrochloride in 2000 g of deionized water to obtain an initiator solution B, and place it in the second raw material bottle; S3: Feed the mixed solution A and the mixed solution B into a premixer for premixing, and at the same time raise the temperature to 90 °C to obtain a mixed solution C; S4: Feed the mixed solution C into the reaction tube, carry out the reaction at 90 °C for 3 min, and after the reaction is completed, it enters the collection bottle through the outlet to complete the synthesis of the phosphorus-containing block polymer.

[0030] In this example, the conversion rate of acrylic acid monomer is 99.30%, the weight-average relative molecular mass Mw is 24674, and the polydispersity is 2.66.

[0031] Example 6: S1: Mix 184 g of vinylphosphonic acid with 1000 g of PEG(10) methacrylate to obtain a mixed solution A, and place it in the first raw material bottle; S2: Dissolve 9.2 g of ammonium persulfate in 2000 g of deionized water to obtain solution B of the initiator, and place it in the second raw material bottle; S3: Feed mixed solution A and mixed solution B into a premixer for premixing, and simultaneously raise the temperature to 90 °C to obtain mixed solution C; S4: Feed mixed solution C into a reaction tube and carry out the reaction at 90 °C for a reaction duration of 3 min. After the reaction is completed, it enters the collection bottle through the outlet to complete the synthesis of the phosphorus-containing block polymer.

[0032] In this example, the conversion rate of PEG(10) methacrylate monomer is 95.0%, the weight-average relative molecular mass Mw is 58195, and the polydispersity is 4.0.

[0033] Example 7: S1: Mix 184 g of vinylphosphonic acid with 500 g of ethyl acrylate to obtain mixed solution A, and place it in the first raw material bottle; S2: Dissolve 9.2 g of ammonium persulfate in 768 g of deionized water to obtain solution B of the initiator, and place it in the second raw material bottle; S3: Feed mixed solution A and mixed solution B into a premixer for premixing, and simultaneously raise the temperature to 90 °C to obtain mixed solution C; S4: Feed mixed solution C into a reaction tube and carry out the reaction at 90 °C for a reaction duration of 3 min. After the reaction is completed, it enters the collection bottle through the outlet to complete the synthesis of the phosphorus-containing block polymer.

[0034] In this example, the conversion rate of ethyl acrylate monomer is 98.0%, the weight-average relative molecular mass Mw is 80918, and the polydispersity is 3.8.

[0035] Example 8: S1: Mix 440 g of dibutyl vinylphosphonate with 144 g of acrylic acid to obtain mixed solution A, and place it in the first raw material bottle; S2: Dissolve 8.8 g of 2,2'-azobis(2-methylpropionamidine) dihydrochloride in 280 g of deionized water to obtain solution B of the polyinitiator, and place it in the second raw material bottle; S3: Feed mixed solution A and mixed solution B into a premixer for premixing, and simultaneously raise the temperature to 80 °C to obtain mixed solution C; S4: Feed mixed solution C into a reaction tube and carry out the reaction at 80 °C for a reaction duration of 3 min. After the reaction is completed, it enters the collection bottle through the outlet to complete the synthesis of the phosphorus-containing block polymer.

[0036] In this example, the conversion rate of acrylic acid monomer is 99.47%, the weight-average relative molecular mass Mw is 21853, and the polydispersity is 3.30.

[0037] Comparative Example 1 368 g of vinylphosphonic acid was added to a reaction kettle and heated to 60 °C. 8.1 g of 2,2'-azobis(2-methylpropionamidine) dihydrochloride was dissolved in 280 g of deionized water for standby. 144 g of acrylic acid and the above initiator solution were respectively pumped into the reaction kettle through a pumping system, and the reaction was carried out at 60 °C for 6 hours.

[0038] In this comparative example, the conversion rate of acrylic acid monomer was 99.47%, the weight-average relative molecular mass Mw was 48286, and the polydispersity was 3.48.

[0039] Comparative Example 2 184 g of vinylphosphonic acid was added to a reaction kettle and heated to 70 °C. 4.2 g of 4,4'-azobis(4-cyanovaleric acid sodium salt) was dissolved in 384 g of deionized water for standby. 301 g of methacrylic acid and the above initiator solution were respectively pumped into the reaction kettle through a pumping system, and the reaction was carried out at 70 °C for 6 hours.

[0040] In this comparative example, the conversion rate of methacrylic acid monomer was 99.25%, the weight-average relative molecular mass Mw was 169151, and the polydispersity was 5.97.

[0041] Comparative Example 3 184 g of vinylphosphonic acid was added to a reaction kettle and heated to 70 °C. 9.2 g of ammonium persulfate was dissolved in 384 g of deionized water for standby. 1000 g of PEG(10) methacrylate and the above initiator solution were respectively pumped into the reaction kettle through a pumping system, and the reaction was carried out at 70 °C for 10 hours.

[0042] In this comparative example, the conversion rate of PEG(10) methacrylate monomer was 85%, the weight-average relative molecular mass Mw was 112510, and the polydispersity was 6.7. Comparing the experimental results of Example 1 and Comparative Example 1, the weight-average relative molecular mass Mw of the phosphorus-containing block polymer prepared in Example 1 was 16243, and the polydispersity was 1.87, indicating that the molecular weight of the polymer was moderate and the distribution was relatively narrow. The weight-average relative molecular mass Mw of the polymer in Comparative Example 1 was 48286, and the polydispersity was 3.48. The molecular weight was higher and the distribution was wider, which would affect its performance in practical applications. In addition, the monomer conversion rates of both were 99.47%, indicating that the two had comparable effects in terms of monomer conversion. However, considering that the reaction time of Example 1 was shorter, its conversion efficiency was actually higher.

[0043] Example 1 adopted a premixer to premix solution A and B, and directly introduced them into the reaction tube for reaction. The whole process was more concise and efficient. Comparative Example 1, on the other hand, adopted the method of pumping the monomer and the initiator into the reaction kettle separately, and the reaction time was as long as 6 hours. The process was more cumbersome and time-consuming. The too long reaction time also increased the uncertainty during the reaction and the generation of by-products. Example 1 ensured the rapidity and stability of the reaction.

[0044] It can also be observed from the experimental results that the premixing step in Example 1 helped the polymerization monomer and the initiator to be fully mixed before the reaction, enabling the reaction to occur more uniformly in the reaction tube, which was conducive to generating a polymer with a narrower molecular weight distribution. In Comparative Example 1, the monomer and the initiator were added separately, which led to uneven local concentration at the initial stage of the reaction and affected the structure and properties of the polymer.

[0045] Example 2 is the same as Comparative Example 2.

[0046] As mentioned above, it is only the preferred embodiments of the present invention, and it does not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications into equivalent embodiments by using the disclosed technical content within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any brief modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for synthesizing a phosphorus-containing block polymer, characterized in that, The polymer is synthesized from a first polymerization monomer and a second polymerization monomer by an initiator using water as a solvent. Among them, the general formula of the first polymerization monomer is as follows. ， R1 is H or a saturated alkyl group with 1 to 10 carbon atoms. The general formula of the second polymerization monomer is as follows. ， Wherein R2 is H or a saturated alkyl group, and R3 is one of H, an alkyl substituent, an alkyl substituent with a hydroxyl group, and a polymerizable acrylate monomer containing 1 to 10 polyether structural units. The specific process of the synthesis is as follows. S1: Mix the first polymerization monomer and the second polymerization monomer to obtain a mixed solution A, and place it in a first raw material bottle. S2: Dissolve the initiator in deionized water to obtain a solution B of the initiator, and place it in a second raw material bottle. S3: Feed the mixed solution A and the mixed solution B into a premixer for premixing, and at the same time heat up to 60 - 90 °C to obtain a mixed solution C. S4: Feed the mixed solution C into a reaction tube, carry out the reaction at 60 - 90 °C, the reaction time is 1 - 4 min, and after the reaction is completed, it enters a collection bottle through an outlet to complete the synthesis of the phosphorus-containing block polymer.

2. The synthesis method of a phosphorus-containing block polymer according to claim 1, characterized in that, The molar ratio of the first polymerization monomer to the second polymerization monomer in S1 is (0.1 - 10):

1.

3. The synthesis method of a phosphorus-containing block polymer according to claim 1, wherein, The initiator in S2 is one or more of potassium persulfate, ammonium persulfate, 2,2'-azobis(2-methylpropionamidine) dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane] disulfate dihydrate, 2,2'-azobis[2-(2-imidazolin-2-yl)propane], 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] n and 4,4'-azobis(4-cyanovaleric acid sodium salt).

4. A method for synthesizing a phosphorus-containing block polymer according to claim 1, characterized in that, The mass ratio of the initiator to deionized water in S2 is (0.01 - 0.03):1, and the mass of the initiator is 1 - 5% of the mass of the phosphorus-containing monomer.

5. A method for synthesizing a phosphorus-containing block polymer according to claim 1, characterized in that, The weight-average molecular weight range of the phosphorus-containing block polymer prepared in S4 is 15000 - 90000.

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