Star polymer with high and low critical solution temperature responsiveness as well as preparation method and application thereof

Abstract

The invention discloses a star polymer with high and low critical solution temperature responsiveness as well as a preparation method and application of the star polymer. A phytic acid functional monomer PA-GMA, dimethylamino ethyl methacrylate DMEMA and 4-acryloyl benzophenone hydroxybenzoate ABP are subjected to free radical polymerization in an aqueous solution in the presence of an initiator; the star polymer with high and low critical solution temperature responsiveness not only has LCST and UCST at the same time, but also has the characteristics of high solubility, low crystallinity, small hydrodynamic volume, high-density functional group distribution, easiness in surface modification and the like, and is more suitable for practical biological medicine and agricultural generation application scenes; the method has potential application value in the field of intelligent biomedical and agricultural chemical materials.

Description

Technical Field

[0001] The invention belongs to the technical field of high molecular polymers, and in particular relates to a star polymer with both high and low critical solution temperature responsiveness and a preparation method thereof. Background Art

[0002] Thermosensitive polymers are a class of intelligent polymers that can respond to temperature stimuli. Their physical and chemical properties and structures will mutate with changes in ambient temperature, and they show unusual temperature responsiveness in aqueous solutions. When a thermosensitive polymer is heated to a certain temperature, it changes from soluble to insoluble, and the polymer is said to have a lower critical solution temperature (LCST); on the contrary, if the polymer changes from insoluble to soluble when heated to a certain temperature, the polymer is said to have a higher critical solution temperature (UCST). For polymers with LCST, hydrogen bonds exist between the polymer molecular chains and water molecules at low temperatures, and they are in a state of freely extended random coils. When the temperature is higher than the LCST, the hydrogen bonds between the polymer and the solvent are destroyed, the hydrophilic segments begin to transform into hydrophobic segments, and the molecular chains aggregate and phase separation occurs. The opposite is true for UCST polymers.

[0003] Thermosensitive polymers often contain functional groups such as ether bonds, substituted amides and hydroxyl groups, such as poly (N-isopropylacrylamide), polyoxyethylene ether, polyvinylpyrrolidone, etc. The outstanding feature of such polymers is that they have significant fluid mechanical volume changes during the response process. They can be effectively used in water treatment, improving oil recovery, controlling drug release, fluid drag reduction, personal care products, etc.

[0004] In recent years, polymers with dual thermal responses of LCST and UCST have become a research hotspot, but there are few reports on star-shaped thermosensitive polymers with both LCST and UCST properties in water. How to design and synthesize star-shaped thermosensitive water-soluble polymers with both LCST and UCST properties from conventional monomers and polymer raw materials is a challenge in the current research of smart polymer materials. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0007] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a star polymer having both high and low critical solution temperature responsiveness.

[0008] In order to solve the above technical problems, the present invention provides the following technical solution:

[0009] a. A repeating unit derived from a phytic acid functional monomer PA-GMA having a structural formula as shown in formula (I);

[0010]

[0011] b. a repeating unit derived from dimethylaminoethyl methacrylate DMEMA and 4-acryloylhydroxybenzoic acid benzophenone ABP connected to the terminal C=C double bond of the phytic acid functional monomer PA-GMA shown in formula (I), which has a structure shown in formula (II), wherein m and n represent the number of repeating units, and m and n are non-zero integers;

[0012]

[0013] c. The molar ratio of the phytic acid functional monomer in the repeating unit to the dimethylaminoethyl methacrylate and 4-acryloylhydroxybenzoic acid benzophenone in the repeating unit is 1:100:2-15.

[0014] The molar ratio of the repeating unit phytic acid functional monomer and dimethylaminoethyl methacrylate to the repeating unit 4-acryloylhydroxybenzoic acid benzophenone is 1:100:2-15.

[0015] As a preferred embodiment of the method for preparing the star polymer having both high and low critical solution temperature responsiveness of the present invention, the star polymer is PAGMA-s-(DMEMA-co-ABP).

[0016] As a preferred embodiment of the method for preparing the star polymer with both high and low critical solution temperature responsiveness of the present invention, the star polymer has both a low critical solution temperature LCST and a high critical solution temperature UCST.

[0017] Another object of the present invention is to provide a method for preparing a star polymer having both high and low critical solution temperature responsiveness.

[0018] In order to solve the above technical problems, the present invention provides the following technical solutions: comprising:

[0019] Phytic acid functional monomer PA-GMA, dimethylaminoethyl methacrylate DMEMA, 4-acryloylhydroxybenzoic acid benzophenone ABP are mixed with distilled water in a molar ratio of 1:100:2-15, and after nitrogen is introduced for 30-60 minutes, 0.5-2wt% of the initiator of the total mass of the raw materials is added, and the mixture is heated to 20-50° C. in a water bath, and a free radical polymerization reaction is carried out for 6-12 hours under nitrogen protection. After the reaction is completed, the reaction solution is dropped into acetone to precipitate a white precipitate, and the filter cake is vacuum dried after suction filtration to obtain a star polymer PAGMA-s-(DMEMA-co-ABP).

[0020] As a preferred embodiment of the method for preparing the star polymer with both high and low critical solution temperature responsiveness of the present invention, the method for preparing the phytic acid functional monomer PA-GMA comprises:

[0021] Phytic acid, urea, inhibitor and distilled water are stirred and dissolved to obtain a mixed solution I, wherein the mass ratio of phytic acid, urea, inhibitor and distilled water is 50-70: 0.05-0.3: 0.01-0.08: 30-50, and the mixture is heated to 20-50° C. in a water bath. Under nitrogen protection and stirring, glycidyl methacrylate is added dropwise to the mixed solution I within 30 min-3 h. After the addition is completed, the reaction is continued for 4-8 h to obtain a phytic acid functional monomer.

[0022] As a preferred embodiment of the method for preparing the star polymer with both high and low critical solution temperature responsiveness of the present invention, the polymerization inhibitor comprises one of hydroquinone or p-hydroxyanisole.

[0023] As a preferred embodiment of the method for preparing the star polymer with both high and low critical solution temperature responsiveness of the present invention, the molar ratio of phytic acid to glycidyl methacrylate is 1:3-6.

[0024] As a preferred embodiment of the method for preparing a star polymer having both high and low critical solution temperature responsiveness of the present invention, the initiator is composed of a water-soluble oxidant and a reducing agent, wherein:

[0025] The oxidant includes one or more of potassium persulfate, ammonium persulfate, hydrogen peroxide, etc.;

[0026] The reducing agent includes one or more of sulfite, bisulfite, ascorbic acid and pyrosulfite.

[0027] As a preferred embodiment of the method for preparing the star polymer with both high and low critical solution temperature responsiveness of the present invention, the molar ratio of the oxidant to the reductant in the initiator is >1.

[0028] Another object of the present invention is to provide a star polymer having both high and low critical solution temperature responsiveness as an intelligent polymer material for use in intelligent biomedical and agrochemical materials.

[0029] Beneficial effects of the present invention:

[0030] The present invention innovatively designs and synthesizes a phytic acid functional monomer containing a double bond, which is significantly different from the molecular structure of conventional phytic acid. Based on the phytic acid functional monomer containing a double bond, a ternary polymer with a star structure is designed. The ternary polymer is a thermosensitive star polymer, which has both LCST and UCST, and has the characteristics of high solubility, low crystallinity, small fluid mechanics volume, high-density functional group distribution, and easy surface modification and modification.

[0031] The raw materials selected by the present invention are cheap and easily available, the synthesis process is simple, and it is green and environmentally friendly. The prepared star polymer is more in line with actual biomedical and agricultural production application scenarios, and has potential application value in the field of intelligent biomedical and agricultural chemical materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0033] Figure 1 The schematic diagram of the preparation process of the star polymer of the present invention is shown in FIG.

[0034] Figure 2 This is the infrared spectrum of the star polymer prepared in Example 1 of the present invention.

[0035] Figure 3 The graph shows the change of transmittance of aqueous solution of star polymer (Example 1) with temperature at different concentrations.

[0036] Figure 4 The light transmittance of a 10% concentration aqueous solution of a star polymer (Example 1 to Example 4) changes with temperature. DETAILED DESCRIPTION

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0038] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0039] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0040] Unless otherwise specified, the raw materials used in the present invention are all commercially available in the art.

[0041] The temperature-sensitive performance test of the star polymer obtained by the present invention is as follows:

[0042] The transmittance of the sample solution containing the star polymer was measured by UV-visible spectrophotometer. The sample solution of a certain concentration was spectrally scanned in the wavelength range of 380-800nm, and the optimal wavelength for measurement was determined to be 560nm. The temperature change rate was 1.0℃ / min, and the curve of the change of the transmittance of the sample solution with temperature was measured at the optimal wavelength to determine the high and low critical solution temperature responsiveness.

[0043] Example 1

[0044] Reference Figure 1 This embodiment provides a method for preparing a star polymer having both high and low critical solution temperature responsiveness, specifically:

[0045] 1) Preparation of phytic acid functional monomer (PA-GMA):

[0046] In a 500mL four-necked round-bottom flask equipped with a thermometer, an electric stirrer, a constant pressure dropping funnel, and a nitrogen conduit, 0.15mol of a phytic acid solution of 70% phytic acid, 1% of urea, and 0.1% of p-hydroxyanisole were added and stirred to dissolve, and then heated to 30°C in a water bath. Under nitrogen protection, 0.9mol of glycidyl methacrylate was added to the constant pressure dropping funnel. Under stirring, glycidyl methacrylate was added dropwise within 2h, and the dropping speed was strictly controlled to ensure that the temperature did not exceed 40°C during the dropping process. After all the additions were completed, the reaction was carried out at a constant temperature of 45°C for 5h, and the reaction solution became homogeneous, and the reaction was stopped to obtain PA-GMA;

[0047] 2) Preparation of star polymer (PAGMA-s-(DMEMA-co-ABP)):

[0048] In a 500mL three-necked round-bottom flask equipped with a thermometer, an electric stirrer, and a nitrogen conduit, 7.56gPA-GMA, 78.5gdimethylaminoethyl methacrylate (DMEMA), 3.12g4-acryloylhydroxybenzoic acid benzophenone (ABP) (the molar ratio of PA-GMA, DMEMA and ABP is 1:100:2.4) and 133.77gdistilled water were added and stirred to dissolve, and then nitrogen was passed for 30min, and then 0.89g sodium bisulfite (1wt% of the total mass of the monomer) and 0.89g ammonium persulfate (1wt% of the total mass of the monomer) were added in sequence, and the water bath was heated to 30°C, and the reaction was carried out under nitrogen protection for 6h. After the reaction was completed, the reaction solution was dropped into acetone to precipitate a white precipitate. After suction filtration, the filter cake was vacuum dried to obtain a star polymer PAGMA-s-(DMEMA-co-ABP) with high and low critical solution temperature responsiveness.

[0049] Figure 2 The infrared spectrum of the star polymer prepared in this example shows that 1720 cm -1 The stretching vibration absorption peak of the ester carbonyl group appears at 1458 cm -1 and 1386cm -1 The deformation vibration absorption peak of the methyl group in the dimethyl structure appears at 1649 cm -1 The stretching vibration absorption peak of benzophenone carbonyl group appears at 1556cm -1 The benzene ring carbon-carbon skeleton stretching vibration peak appears at 1234 cm -1 The peak of P=O stretching vibration is 3435cm -1 The -OH stretching vibration peak is at 1076 cm -1 The peak at is the typical stretching vibration absorption peak of phytic acid POC. The infrared spectrum analysis shows that the three functional monomers have undergone polymerization and the functional group absorption peak unique to the target product has appeared.

[0050] Figure 3 The graph showing the change in light transmittance of aqueous solutions of star polymers of different concentrations prepared in this embodiment with temperature shows that with the increase in the concentration of the star polymer solution, the upper and lower critical solution temperatures decrease significantly. The effect of concentration change on the critical solution temperature of the polymer is mainly due to the change in the average distance between macromolecular monomer chains with the change in concentration, which in turn leads to changes in the probability of contact between molecular chains, hydrophobic interactions, hydrogen bonding between molecules, and hydrogen bonding between polymers and water, thereby changing the phase transition temperature and temperature sensitivity of the solution.

[0051] Example 2

[0052] The difference between this embodiment and embodiment 1 is that step 2) is adjusted, specifically:

[0053] In a 500mL three-necked round-bottom flask equipped with a thermometer, an electric stirrer, and a nitrogen inlet, 7.56g PA-GMA, 78.5g dimethylaminoethyl methacrylate (DMEMA), 5.46g 4-acryloylhydroxybenzoic acid benzophenone (ABP) (the molar ratio of PA-GMA, DMEMA, and ABP is 1:100:4) and 136.11g distilled water were added and stirred to dissolve, and then nitrogen was passed for 30 minutes. Then, 0.91g sodium bisulfite and 0.91g ammonium persulfate were added in sequence, and the mixture was heated to 30°C in a water bath and reacted for 6 hours under nitrogen protection. After the reaction was completed, the reaction solution was dropped into acetone to precipitate a white precipitate. After suction filtration, the filter cake was vacuum dried to obtain a star polymer PAGMA-s-(DMEMA-co-ABP) with high and low critical solution temperature responsiveness.

[0054] Example 3

[0055] The difference between this embodiment and embodiment 1 is that step 2) is adjusted, specifically:

[0056] In a 500mL three-necked round-bottom flask equipped with a thermometer, an electric stirrer, and a nitrogen conduit, 7.56gPA-GMA, 78.5gdimethylaminoethyl methacrylate (DMEMA), 4.68g4-acryloylhydroxybenzoic acid benzophenone (ABP) (the molar ratio of PA-GMA, DMEMA and ABP is 1:100:3.6) and 137.28g of distilled water were added and stirred to dissolve, and nitrogen was passed for 30min, and then 0.92g sodium bisulfite and 0.92g ammonium persulfate were added in sequence, heated to 30°C in a water bath, and reacted for 6h under nitrogen protection. After the reaction was completed, the reaction solution was dropped into acetone to precipitate a white precipitate, and the filter cake was vacuum dried after suction filtration to obtain the star polymer of this embodiment.

[0057] Example 4

[0058] The difference between this embodiment and embodiment 1 is that step 2) is adjusted, specifically:

[0059] In a 500mL three-necked round-bottom flask equipped with a thermometer, an electric stirrer, and a nitrogen conduit, 7.56gPA-GMA, 78.5gdimethylaminoethyl methacrylate (DMEMA), 6.24g4-acryloylhydroxybenzoic acid benzophenone (ABP) (the molar ratio of PA-GMA, DMEMA and ABP is 1:100:5) and 138.45g of distilled water were added and stirred to dissolve, and then nitrogen was passed for 30min, and then 0.93g sodium bisulfite and 0.93g ammonium persulfate were added in sequence, heated to 30°C in a water bath, and reacted for 6h under nitrogen protection. After the reaction was completed, the reaction solution was dropped into acetone to precipitate a white precipitate, and the filter cake was vacuum dried after suction filtration to obtain the star polymer of this embodiment.

[0060] Figure 4For the star polymers prepared in Examples 1 to 4, the transmittance of the aqueous solution configured to have a concentration of 10% changes with temperature. It can be seen that with the increase of the content of 4-acryloylhydroxybenzoic acid benzophenone in the synthesis formula, the critical solution temperature of the synthesized star polymer solution is significantly reduced. The main reason is that the hydrophobicity of the polymer increases and the hydrophilicity decreases. Therefore, the critical solution temperature of the star polymer can be regulated by adjusting the polymer composition ratio to meet the actual needs of various application fields.

[0061] In summary, the present invention innovatively designs and synthesizes a phytic acid functional monomer containing a double bond, which is significantly different from the molecular structure of conventional phytic acid. Based on the phytic acid functional monomer containing a double bond, a ternary polymer with a star structure is designed. The ternary polymer is a thermosensitive star polymer, which has both LCST and UCST, and has the characteristics of high solubility, low crystallinity, small fluid mechanics volume, high-density functional group distribution, and easy surface modification and modification.

[0062] The raw materials selected by the present invention are cheap and easily available, the synthesis process is simple, and it is green and environmentally friendly. The prepared star polymer is more in line with actual biomedical and agricultural production application scenarios, and has potential application value in the field of intelligent biomedical and agricultural chemical materials.

[0063] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A star polymer having both high and low critical solution temperature responsiveness, characterized in that: It is composed of: a. A repeating unit derived from a phytic acid functional monomer PA-GMA having a structural formula as shown in formula (I); b. a repeating unit derived from dimethylaminoethyl methacrylate DMEMA and 4-acryloylhydroxybenzoic acid benzophenone ABP connected to the terminal C=C double bond of the phytic acid functional monomer PA-GMA shown in formula (I), which has a structure shown in formula (II), wherein m and n represent the number of repeating units, and m and n are non-zero integers; c. The molar ratio of the phytic acid functional monomer in the repeating unit to the dimethylaminoethyl methacrylate and 4-acryloylhydroxybenzoic acid benzophenone in the repeating unit is 1:100:2-15.

2. The star polymer having both high and low critical solution temperature responsiveness according to claim 1, characterized in that: The star polymer is PAGMA-s-(DMEMA-co-ABP).

3. The star polymer having both high and low critical solution temperature responsiveness according to any one of claims 1 or 2, characterized in that: The star polymer has both a lower critical solution temperature LCST and an upper critical solution temperature UCST.

4. A method for preparing a star polymer having both high and low critical solution temperature responsiveness as claimed in any one of claims 1 to 3, characterized in that: include, Phytic acid functional monomer PA-GMA, dimethylaminoethyl methacrylate DMEMA, 4-acryloylhydroxybenzoic acid benzophenone ABP are mixed with distilled water in a molar ratio of 1:100:2-15, and after nitrogen is introduced for 30-60 minutes, an initiator of 0.5-2wt% of the total mass of the raw materials is added, and a water bath is heated to 20-50° C., and a free radical polymerization reaction is carried out for 6-12 hours under nitrogen protection. After the reaction is completed, the reaction solution is dripped into acetone to precipitate a white precipitate, and the filter cake is vacuum dried after suction filtration to obtain a star polymer PAGMA-s-(DMEMA-co-ABP).

5. The method for preparing a star polymer having both high and low critical solution temperature responsiveness according to claim 4, characterized in that: The preparation method of the phytic acid functional monomer PA-GMA comprises: Phytic acid, urea, inhibitor and distilled water are stirred and dissolved to obtain a mixed solution I, wherein the mass ratio of phytic acid, urea, inhibitor and distilled water is 50-70: 0.05-0.3: 0.01-0.08: 30-50, and the mixture is heated to 20-50° C. in a water bath. Under nitrogen protection and stirring, glycidyl methacrylate is added dropwise to the mixed solution I within 30 min-3 h. After the addition is completed, the reaction is continued for 4-8 h to obtain a phytic acid functional monomer.

6. The method for preparing a star polymer having both high and low critical solution temperature responsiveness according to claim 5, characterized in that: The polymerization inhibitor includes one of hydroquinone or p-hydroxyanisole.

7. The method for preparing a star polymer having both high and low critical solution temperature responsiveness according to claim 5, characterized in that: The molar ratio of the phytic acid to the glycidyl methacrylate is 1:3-6.

8. The method for preparing a star polymer having both high and low critical solution temperature responsiveness according to claim 4, characterized in that: The initiator is composed of a water-soluble oxidizing agent and a reducing agent, wherein: The oxidant includes one or more of potassium persulfate, ammonium persulfate, hydrogen peroxide, etc.; The reducing agent includes one or more of sulfite, bisulfite, ascorbic acid and pyrosulfite.

9. The method for preparing a star polymer having both high and low critical solution temperature responsiveness according to claim 8, characterized in that: The molar ratio of the oxidant to the reductant in the initiator is >1.

10. Application of the star polymer with both high and low critical solution temperature responsiveness as claimed in claim 1 as an intelligent polymer material in intelligent biomedical and agrochemical materials.

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