Polymer gel having sponge-like porous structure

Patent metadata

Field	Value
Publication number	US-12227642-B2
Application number	US-201917263403-A
Country	US
Kind code	B2
Filing date	Jul 29, 2019
Priority date	Jul 31, 2018
Publication date	Feb 18, 2025
Grant date	Feb 18, 2025

Abstract

An object of the present invention is to provide a gel material including a solvophilic polymer having a μm-scale porous structure.
A polymer gel in which solvophilic polymer units are cross-linked with each other, wherein the polymer gel contains a solvent and has a three-dimensional network structure having two regions: a first region in which the polymer units are densely present and a second region in which the polymer units are sparsely present, and a mesh size composed of the first region is from 1 to 500 μm.

First claim

The invention claimed is:

1. A polymer gel in which solvophilic polymer units are cross-linked with each other,
wherein the polymer gel contains a solvent and has a three-dimensional network structure having two regions: a first region in which the solvophilic polymer units are densely present and a second region in which the solvophilic polymer units are sparsely present, and
a mesh size composed of the first region is in the range of 1 to 500 μm.

2. The polymer gel according to claim 1 , wherein the polymer gel has a lower permeability than a permeability of the solvophilic polymer units before gelation.

3. The polymer gel according to claim 1 or 2 , wherein the polymer gel has an osmotic pressure of ⅕ to ½ of an osmotic pressure of the solvophilic polymer units before gelation.

4. The polymer gel according to claim 1 , wherein an osmotic pressure (Π os ) and an elastic pressure (Π el ) after a lapse of a certain period of time from gelation have a relationship of Π el >Π os .

5. The polymer gel according to claim 1 , wherein a polymer concentration in the first region is from 10 to 99 wt %, and a polymer concentration in the second region is from 0 to 1 wt %.

6. The polymer gel according to claim 1 , wherein the polymer gel has a polymer content of 5 wt % or less.

7. The polymer gel according to claim 1 , wherein the solvent is water and the solvophilic polymer units are hydrophilic polymer units.

8. The polymer gel according to claim 7 , wherein the hydrophilic polymer units are polymers having a polyethylene glycol backbone or a polyvinyl backbone.

9. The polymer gel according to claim 1 , wherein the solvophilic polymer units comprise a first polymer unit having one or more nucleophilic functional groups in a side chain or at an end and a second polymer unit having one or more electrophilic functional groups in a side chain or at an end.

10. The polymer gel according to claim 9 , wherein the one or more nucleophilic functional groups are selected from the group consisting of a thiol group, an amino group, and —CO 2 PhNO 2 , and the one or more electrophilic functional groups are selected from the group consisting of a maleimidyl group, an N-hydroxy-succinimidyl (NHS) group, a sulfosuccinimidyl group, a phthalimidyl group, an imidazolyl group, an acryloyl group, and a nitrophenyl group.

11. A process for producing a polymer gel comprising:
a) crosslinking solvophilic raw polymers under conditions of less than an overlapping concentration and less than a critical gelation concentration to form gel precursors, wherein the gel precursors have a relationship of G′<G″ between a storage modulus G′ and a loss modulus G″;
b) crosslinking the gel precursors with each other using a crosslinking agent to obtain the polymer gel; and
c) allowing the polymer gel to stand in water for at least 7 days;
wherein the polymer gel has a three-dimensional structure including two regions: a first region in which polymer units derived from the solvophilic raw polymers are densely present and a second region in which polymer units derived from the solvophilic raw polymers are sparsely present and a mesh size composed of the first region is in the range of 1 to 500 μm.

12. A process for producing a polymer gel comprising
a) crosslinking solvophilic raw polymers having a concentration of less than an overlapping concentration and equal to or more than a critical gelation concentration with each other in the presence of a non-reactive polymer having a predetermined concentration to obtain the polymer gel, and
b) allowing the polymer gel to stand in water for at least 7 days;
wherein the non-reactive polymer is a polymer having no functional group capable of crosslinking with the raw polymers in a molecule, and
the polymer gel has a three-dimensional structure including two regions: a first region in which polymer units derived from the solvophilic raw polymers are densely present and a second region in which polymer units derived from the solvophilic raw polymers are sparsely present and a mesh size composed of the first region is in the range of 1 to 500 μm.

13. The process for producing a polymer gel according to claim 11 or 12 , wherein the solvophilic raw polymers are hydrophilic polymers.

14. The process for producing a polymer gel according to claim 13 , wherein the hydrophilic polymers are polymers having a polyethylene glycol backbone or a polyvinyl backbone.

15. The process for producing a polymer gel according to claim 11 or 12 , wherein the solvophilic raw polymers comprise a first polymer having one or more nucleophilic functional groups in a side chain or at an end and a second polymer having one or more electrophilic functional groups in a side chain or at an end.

16. The process for producing a polymer gel according to claim 15 , wherein the one or more nucleophilic functional groups are selected from the group consisting of a thiol group, an amino group, and —CO 2 PhNO 2 , and the one or more electrophilic functional groups are selected from the group consisting of a maleimidyl group, an N-hydroxy-succinimidyl (NHS) group, a sulfosuccinimidyl group, a phthalimidyl group, an imidazolyl group, an acryloyl group, and a nitrophenyl group.

17. The process for producing a polymer gel according to claim 11 , wherein the gel precursors have a diameter of 10 to 1000 nm.

18. The process for producing a polymer gel according to claim 11 , wherein the gel precursors comprise a first gel precursor and a second gel precursor,
the first gel precursor and the second gel precursor both have a first polymer having one or more nucleophilic functional groups in a side chain or at an end and a second polymer having one or more electrophilic functional groups in a side chain or at an end,
the first gel precursor has a higher first polymer content than a second polymer content, and the second gel precursor has a higher second polymer content than a first polymer content.

19. The process for producing a polymer gel according to claim 11 , wherein step b) is conducted in the presence of a non-reactive polymer having no functional group capable of crosslinking with the gel precursor in the molecule.

20. The process for producing a polymer gel according to claim 12 or 19 , wherein the non-reactive polymer is polyethylene glycol or cellulose, which has no crosslinking reactive group.

Assignees

• Univ Tokyo

Inventors

• Sakai Takamasa
• Tei Yuichi

Classifications

• C08J2471/02

  Polyalkylene oxides · CPC title

• C08J2401/02

  Cellulose; Modified cellulose · CPC title

• C08J2371/02

  Polyalkylene oxides · CPC title

• C08J2205/028

  Xerogel, i.e. an air dried gel · CPC title

• C08J9/28 Primary

  by elimination of a liquid phase from a macromolecular composition or article, e.g. drying of coagulum · CPC title