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CN-121991268-A - Homopolymer with UCST temperature sensitivity and pH responsiveness and preparation method thereof

CN121991268ACN 121991268 ACN121991268 ACN 121991268ACN-121991268-A

Abstract

The invention belongs to the technical field of stimulus response functional polymers, and relates to a homopolymer with UCST temperature sensitivity and pH responsiveness and a preparation method thereof. The monomer for synthesizing the homopolymer has a structure shown in a formula (II), and the prepared homopolymer with UCST temperature sensitivity and pH responsiveness has a structure shown in a formula (I). The homopolymer has gradually improved solubility with increasing temperature, and shows obvious UCST phase transition characteristics. Meanwhile, as the pH of the solution increases, the solubility of the polymer gradually increases, and the required phase transition temperature gradually decreases, which indicates that the temperature response behavior of the polymer can be regulated by the pH. The homopolymer has wide application prospect in the fields of biological medicines and intelligent materials.

Inventors

  • ZHANG YANQIN
  • HUANG JIANBING

Assignees

  • 广州工程技术职业学院

Dates

Publication Date
20260508
Application Date
20260128

Claims (10)

  1. 1.A homopolymer having UCST temperature sensitivity and pH responsiveness, characterized by having a structure represented by formula (I): (I)。
  2. 2. The homopolymer having UCST temperature sensitivity and pH responsiveness according to claim 1, wherein the homopolymer is prepared from a monomer having a structure represented by formula (II): (II)。
  3. 3. A homopolymer having UCST temperature sensitivity and pH responsiveness according to claim 2, wherein the monomer is prepared by the following method: a. Mixing and dissolving isopropyl acrylamide, glycine and water, regulating the pH to 10 by using 5mol/L potassium hydroxide aqueous solution, reacting for 48 hours at 60 ℃, spin-drying to remove water, washing the crude product by methanol for 3 times, washing the crude product by diethyl ether for 1 time, and vacuum drying to obtain an intermediate; b. Dissolving the intermediate in 10% NaOH solution, gradually adding the acryloyl chloride into the solution under ice bath, then reacting for 6 hours at room temperature, adjusting the pH to 2 with concentrated hydrochloric acid after the reaction, concentrating by rotary evaporation, filtering, collecting precipitated solid, and drying in vacuum to obtain the monomer.
  4. 4. The homopolymer having UCST temperature sensitivity and pH responsiveness according to claim 3, wherein the mass ratio of isopropyl acrylamide, glycine and water in the monomer preparation step a is (1.1-1.3) 1 (6-9).
  5. 5. The homopolymer with UCST temperature sensitivity and pH responsiveness according to claim 3, wherein the mass ratio of the intermediate, 10% NaOH and acryloyl chloride in the monomer preparation step b is 1 (2-3): 0.6-0.8.
  6. 6. A homopolymer having UCST temperature sensitivity and pH responsiveness according to claim 3, wherein the step of preparing the homopolymer from the monomer by polymerization is: Taking 484.0mg of the monomer, 1.3mg of azodiisobutyronitrile, 11.1mg of 4-cyano-4- [ [ (propylthio) thiomethyl ] thio ] pentanoic acid and 2mL of DMF, uniformly mixing in an ampere tube, performing liquid nitrogen cooling, vacuumizing and nitrogen circulation operation for 3 times, sealing the tube, reacting for 24 hours at 65 ℃, cooling, breaking the tube, precipitating in diethyl ether, and vacuum drying to obtain the target polymer.
  7. 7. A method for preparing a homopolymer with UCST temperature sensitivity and pH responsiveness, comprising the following steps: taking 484.0mg of a monomer with a structure shown in a formula (II), 1.3mg of azodiisobutyronitrile, 11.1mg of 4-cyano-4- [ [ (propylthio) thiomethyl ] thio ] pentanoic acid and 2mL of DMF, uniformly mixing in an ampere tube, cooling with liquid nitrogen, vacuumizing, circulating nitrogen for 3 times, sealing the tube, reacting at 65 ℃ for 24 hours, cooling, breaking the tube, precipitating in diethyl ether, and vacuum drying to obtain a target polymer, wherein the structure of the formula (II) is as follows: (II)。
  8. 8. the method for preparing a homopolymer having UCST temperature sensitivity and pH responsiveness according to claim 7, wherein the method for preparing the monomer comprises the steps of: a. Mixing and dissolving isopropyl acrylamide, glycine and water, regulating the pH to 10 by using 5mol/L potassium hydroxide aqueous solution, reacting for 48 hours at 60 ℃, spin-drying to remove water, washing the crude product by methanol for 3 times, washing the crude product by diethyl ether for 1 time, and vacuum drying to obtain an intermediate; b. Dissolving the intermediate in 10% NaOH solution, gradually adding the acryloyl chloride into the solution under ice bath, then reacting for 6 hours at room temperature, adjusting the pH to 2 with concentrated hydrochloric acid after the reaction, concentrating by rotary evaporation, filtering, collecting precipitated solid, and drying in vacuum to obtain the monomer.
  9. 9. The method for preparing a homopolymer having UCST temperature sensitivity and pH responsiveness according to claim 8, wherein the mass ratio of isopropyl acrylamide, glycine and water in the monomer preparation step a is (1.1-1.3): 1 (6-9).
  10. 10. The method for preparing the homopolymer with UCST temperature sensitivity and pH responsiveness according to claim 8, wherein the mass ratio of the intermediate, 10% NaOH and acryloyl chloride in the monomer preparation step b is 1 (2-3) (0.6-0.8).

Description

Homopolymer with UCST temperature sensitivity and pH responsiveness and preparation method thereof Technical Field The invention belongs to the technical field of stimulus response functional polymers, and particularly relates to a homopolymer with UCST temperature sensitivity and pH responsiveness and a preparation method thereof. Background Stimulus responsive polymers have been receiving academic and industrial attention in the past two decades because of their great potential applications in various fields of biomedical, sensing, smart devices, etc. Among them, the temperature-sensitive polymer and the pH-responsive polymer are two types of intelligent materials which are most widely studied. In practical application, the single stimulus-responsive material is sometimes insufficient to achieve accurate regulation and control due to the singleness of stimulus sources, and is difficult to meet the practical application requirements in some complex systems. The temperature and the pH are used as stimulus sources which are very simple to control, the corresponding dual stimulus response polymer is particularly favored, and the application prospect is wide in various fields, especially in the biomedical field. The temperature and pH responsive polymers commonly found today are mostly synthesized by copolymerization. The method has complicated synthesis steps, and the synthesized polymer has uncontrollable structure, so that the property difference among batches is large, and the response behavior is inaccurate. Multiple stimulus-responsive homopolymers are theoretically a solution but the design of monomers and their synthesis remains a great challenge, which also results in few types of temperature and pH responsive homopolymers that have been reported to date. In addition, temperature-sensitive polymers are mainly classified into two types, namely polymers with low critical co-solubility temperature (LCST) and polymers with high critical co-solubility temperature (UCST), and most of common researches on temperature-sensitive polymers are focused on LCST type polymers at present, and the report of UCST type polymers is less, which is also related to the development difficulty of UCST type polymers. The development of the homopolymer which has simple structure, convenient synthesis and clear UCST behavior and pH responsiveness simultaneously becomes a key for breaking through the preparation bottleneck of the current dual-response intelligent material and pushing the current dual-response intelligent material to precision application. Disclosure of Invention In order to solve the above problems, the present invention provides a homopolymer having UCST temperature sensitivity and pH responsiveness and a method for preparing the same. The polymer has UCST type phase transition property in water, and the phase transition behavior of the polymer can be regulated and controlled through pH, so that the polymer is expected to widen the application prospect of the stimulus response intelligent material. In order to achieve the above object, the present invention comprises the following technical solutions: In a first aspect, the present invention provides a homopolymer having UCST temperature sensitivity and pH responsiveness, the structure of which is as in formula (I): (I)。 The homopolymer has UCST type phase transition property in water, and the phase transition behavior of the homopolymer can be regulated by pH. In a second aspect, the present invention provides a monomer for synthesizing the homopolymer having UCST temperature sensitivity and pH responsiveness, which has the structure of formula (II): (II)。 The preparation method of the monomer comprises the following steps: a. Mixing and dissolving isopropyl acrylamide, glycine and water, regulating the pH to 10 by using 5mol/L potassium hydroxide aqueous solution, reacting for 48 hours at 60 ℃, spin-drying to remove water, washing the crude product by methanol for 3 times, washing the crude product by diethyl ether for 1 time, and vacuum drying to obtain an intermediate; b. Dissolving the intermediate in 10% NaOH solution, gradually adding the acryloyl chloride into the solution under ice bath, then reacting for 6 hours at room temperature, adjusting the pH to 2 with concentrated hydrochloric acid after the reaction, concentrating by rotary evaporation, filtering, collecting precipitated solid, and drying in vacuum to obtain the monomer. In addition, in the monomer preparation step a, the mass ratio of the isopropyl acrylamide, the glycine and the water is (1.1-1.3) 1 (6-9). Further, in the monomer preparation step b, the mass ratio of the intermediate to 10% NaOH to the acrylic chloride is 1 (2-3) (0.6-0.8). In a third aspect, the present invention provides a method for preparing a homopolymer having UCST temperature sensitivity and pH responsiveness, comprising the steps of: Taking 484.0mg of the monomer, 1.3mg of azodiisobutyronitrile, 11.1mg of 4-cyano-4-