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CN-122011645-A - Shape memory hydrogel and preparation method and application thereof

CN122011645ACN 122011645 ACN122011645 ACN 122011645ACN-122011645-A

Abstract

The invention discloses a shape memory hydrogel and a preparation method and application thereof, belonging to the technical field of shape memory hydrogel preparation, wherein N-isopropyl acrylamide is used as a functional monomer, 4-vinylpyridine is used as a hydrophobic unit, methacrylic acid-beta-hydroxyethyl is used as a hydrophilic unit, N, N ' -methylene bisacrylamide is used as a cross-linking agent, ammonium persulfate and N, N, N ', N ' -tetramethyl ethylenediamine are used as a composite initiator, and modified carbon quantum dots prepared from carboxyl carbon quantum dots, oxidized dextran and mixed ionic liquid are used as filling units. The hydrogel provided by the invention takes the modified carbon quantum dots as a nano reinforcing phase, and is combined with a composite crosslinking system, wherein the tensile strength is more than or equal to 0.45MPa, and the elongation at break is more than or equal to 400%. The hydrogel has better shape memory performance, the shape memory fixation rate is more than or equal to 98%, the shape memory recovery rate is more than or equal to 97.5%, and the shape memory recovery rate is more than or equal to 95.0% after 10 swelling-shrinking/shape memory cycles of the hydrogel, and the cyclic attenuation amplitude is greatly reduced.

Inventors

  • ZHANG HONGJI
  • ZHU MENGJUN
  • LI YONGWEN

Assignees

  • 江南大学
  • 江苏德纳化学股份有限公司

Dates

Publication Date
20260512
Application Date
20260318

Claims (8)

  1. 1. A shape memory hydrogel is characterized in that N-isopropyl acrylamide is used as a functional monomer, 4-vinylpyridine is used as a hydrophobic unit, methacrylic acid-beta-hydroxyethyl ester is used as a hydrophilic unit, N, N ' -methylene bisacrylamide is used as a cross-linking agent, ammonium persulfate and N, N, N ', N ' -tetramethyl ethylenediamine are used as a composite initiator, and modified carbon quantum dots prepared from carboxyl carbon quantum dots, oxidized dextran and mixed ionic liquid are used as filling units.
  2. 2. The shape memory hydrogel of claim 1, wherein the method for preparing the modified carbon quantum dots comprises the steps of: (1) Weighing 50-55 parts by weight of carboxyl carbon quantum dot powder, 50-80 parts by weight of mixed ionic liquid and 0.8-1.2 parts by weight of oxidized dextran, wherein the mixed ionic liquid is prepared by mixing 1-ethyl-3-methylimidazole bis (trifluoro) methanesulfonimide salt and 1-ethyl-3-methylimidazole tetrafluoroborate according to a mass ratio of 0.2-0.5:1; (2) Sequentially adding carbon quantum dot powder and mixed ionic liquid, stirring at constant temperature of 50-60 ℃ and 400-600r/min for 15-30min, simultaneously adopting 250-350W ultrasonic to assist in dispersing, and then adding oxidized dextran, and stirring at constant temperature of 60-70 ℃ for 1.5-2h; (3) After the reaction is finished, obtaining the modified carbon quantum dot through centrifugal separation, precipitation, washing and drying.
  3. 3. The shape memory hydrogel of claim 1, wherein the mass ratio of beta-hydroxyethyl methacrylate, 4-vinylpyridine, N-isopropylacrylamide is 2-3:1-2:4-5.
  4. 4. The shape memory hydrogel of claim 1, wherein the mass ratio of N, N '-methylenebisacrylamide, N' -tetramethylethylenediamine, ammonium persulfate is 0.03-0.06:0.01-0.02:0.06-0.1.
  5. 5. The shape memory hydrogel according to claim 2, wherein in step (3), after the reaction, the reaction solution is centrifugally separated by 8000-10000r/min, and the precipitate is washed with ethanol and dried under vacuum at 60-65 ℃ to obtain the modified carbon quantum dots.
  6. 6. The shape memory hydrogel of claim 1, wherein the mixed ionic liquid is formed by mixing 1-ethyl-3-methylimidazole bistrifluoromethanesulfonimide salt with 1-ethyl-3-methylimidazole tetrafluoroborate in a mass ratio of 0.2-0.5:1.
  7. 7. A method for preparing the shape memory hydrogel according to any one of claims 1 to 6, comprising the steps of: (1) Sequentially adding methacrylic acid-beta-hydroxyethyl, 4-vinyl pyridine and N-isopropyl acrylamide into 50-80mL of acetic acid-sodium acetate buffer solution, magnetically stirring for 20-30min at 22-25 ℃ and stirring at 300-500rpm to form monomer mixed solution; (2) Adding modified carbon quantum dot powder into the monomer mixed solution, performing ultrasonic dispersion for 30-45min, wherein the ultrasonic power is 200-300W, and the ultrasonic frequency is 45-50kHz, and the modified carbon quantum dot powder is completely dispersed without obvious agglomerated particles; (3) Then adding N, N' -methylene bisacrylamide, and stirring for 10-12min; (4) Firstly adding N, N, N ', N' -tetramethyl ethylenediamine, stirring for 4-5min, slowly dripping ammonium persulfate aqueous solution with mass concentration of 5-8.5% at the rate of 1-2 drops/second, and stirring for 5-10min; (5) Injecting the mixed solution into a die which is coated with a release agent in advance, sealing, standing and polymerizing for 3-5h at 22-25 ℃ to obtain the shape memory hydrogel.
  8. 8. Use of a shape memory hydrogel according to any one of claims 1-6 in a temperature or acid/base gas recognition responsive shape memory hydrogel product.

Description

Shape memory hydrogel and preparation method and application thereof Technical Field The invention relates to the technical field of shape memory hydrogel preparation, in particular to a shape memory hydrogel, a preparation method and application thereof. Background The shape memory hydrogels (shape memoryhydogels, SMHs) fix temporary shapes under specific conditions and recover the original shape under external stimuli. The switchable nature of this architecture makes it a research hotspot. Currently SMHs still has many challenges: 1. The mechanical properties of hydrogels are mostly difficult to meet the load-bearing requirements. 2. Repeated deformation may cause fracture of a crosslinked network, and the problem of weak cyclic stability is needed to be solved. Based on the above, the invention designs a shape memory hydrogel, a preparation method and application thereof to solve the problems. Disclosure of Invention Aiming at the defects existing in the prior art, the invention provides a shape memory hydrogel and a preparation method and application thereof. In order to achieve the above purpose, the invention is realized by the following technical scheme: The shape memory hydrogel takes N-isopropyl acrylamide as a functional monomer, 4-vinyl pyridine as a hydrophobic unit, methacrylic acid-beta-hydroxyethyl ester as a hydrophilic unit, N, N ' -methylene bisacrylamide as a cross-linking agent, ammonium persulfate and N, N, N ', N ' -tetramethyl ethylenediamine as a composite initiator, and modified carbon quantum dots prepared by taking carboxyl carbon quantum dots, oxidized dextran and mixed ionic liquid as raw materials as filling units. Further, the preparation method of the modified carbon quantum dot comprises the following steps: (1) Weighing 50-55 parts by weight of carboxyl carbon quantum dot powder, 50-80 parts by weight of mixed ionic liquid and 0.8-1.2 parts by weight of oxidized dextran, wherein the mixed ionic liquid is prepared by mixing 1-ethyl-3-methylimidazole bis (trifluoro) methanesulfonimide salt and 1-ethyl-3-methylimidazole tetrafluoroborate according to a mass ratio of 0.2-0.5:1; (2) Sequentially adding carbon quantum dot powder and mixed ionic liquid, stirring at constant temperature of 50-60 ℃ and 400-600r/min for 15-30min, simultaneously adopting 250-350W ultrasonic to assist in dispersing, and then adding oxidized dextran, and stirring at constant temperature of 60-70 ℃ for 1.5-2h; (3) After the reaction is finished, obtaining the modified carbon quantum dot through centrifugal separation, precipitation, washing and drying. Further, the mass ratio of the methacrylic acid-beta-hydroxyethyl ester, the 4-vinyl pyridine and the N-isopropyl acrylamide is 2-3:1-2:4-5. Further, the mass ratio of the N, N ' -methylene bisacrylamide, the N, N, N ', N ' -tetramethyl ethylenediamine and the ammonium persulfate is 0.03-0.06:0.01-0.02:0.06-0.1. Further, in the step (3), after the reaction is finished, the reaction solution is centrifugally separated by 8000-10000r/min, and the precipitate is washed by ethanol and dried in vacuum at 60-65 ℃ to obtain the modified carbon quantum dot. Furthermore, the mixed ionic liquid is formed by mixing 1-ethyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt and 1-ethyl-3-methylimidazole tetrafluoroborate according to the mass ratio of 0.2-0.5:1. In order to better achieve the purpose of the invention, the invention also provides a preparation method of the shape memory hydrogel, which comprises the following steps: (1) Sequentially adding methacrylic acid-beta-hydroxyethyl, 4-vinyl pyridine and N-isopropyl acrylamide into 50-80mL of acetic acid-sodium acetate buffer solution, magnetically stirring for 20-30min at 22-25 ℃ and stirring at 300-500rpm to form monomer mixed solution; (2) Adding modified carbon quantum dot powder into the monomer mixed solution, performing ultrasonic dispersion for 30-45min, wherein the ultrasonic power is 200-300W, and the ultrasonic frequency is 45-50kHz, and the modified carbon quantum dot powder is completely dispersed without obvious agglomerated particles; (3) Then adding N, N' -methylene bisacrylamide, and stirring for 10-12min; (4) Firstly adding N, N, N ', N' -tetramethyl ethylenediamine, stirring for 4-5min, slowly dripping ammonium persulfate aqueous solution with mass concentration of 5-8.5% at the rate of 1-2 drops/second, and stirring for 5-10min; (5) Injecting the mixed solution into a die which is coated with a release agent in advance, sealing, standing and polymerizing for 3-5h at 22-25 ℃ to obtain the shape memory hydrogel. In order to better achieve the aim of the invention, the invention also provides the application of the shape memory hydrogel in a temperature or acid/alkali gas recognition response shape memory hydrogel product. Compared with the prior art, the hydrogel has the beneficial effects that 1, the hydrogel takes the modified carbon quantum dots as the nano reinforcing phase, and t