Superabsorbent polymeric structures
Provided herein is a superabsorbent polyHIPE composition-of-matter comprising a majority of ionizable pendant groups, capable of absorbing up to 300-fold by mass water while exhibiting a notable mechanical strength in both the dry and wet form, as well as various uses thereof.
1. A composition-of-matter comprising a crosslinked polymer, the composition-of-matter having a microstructure of a polymerized external phase of a high internal phase emulsion and characterized by a dry density that ranges from 0.05 g/cm 3 to 0.4 g/cm 3 , wherein:
the composition-of-matter is derived from an oil-in-water emulsion which is a high internal phase emulsion that comprises an organic internal phase and an aqueous external phase;
a crosslinking level of said crosslinked polymer ranges from 0.1 to 15 mol percent;
said crosslinked polymer is having a plurality of pendant groups, at least a portion of which are ionizable pendant groups that are more strongly hydrated than a carboxylic pendant group;
such that the composition-of-matter is characterized by:
an equilibrium aqueous medium absorption of at least 8 g/g; and
a compressive failure strain of at least 25% when the composition-of-matter is fully swollen with said aqueous medium.
2. The composition-of-matter of claim 1 , wherein said compressive failure strain of the composition-of-matter is at least 2-fold greater than a compressive failure strain of a reference bulk hydrogel made with said crosslinked polymer but not prepared as an external phase of a high internal phase emulsion.
3. The composition-of-matter of claim 1 , wherein a ratio of said ionizable pendant groups to non-ionizable pendant groups in said crosslinked polymer is greater than 85 percent.
4. The composition-of-matter of claim 1 , wherein said polymer is substantially devoid of non-ionizable pendant groups.
5. The composition-of-matter of claim 1 , wherein said ionizable pendant groups comprise at least one organosulfur group.
6. The composition-of-matter of claim 1 , wherein said microstructure is an open-cell microstructure.
7. The composition-of-matter of claim 1 , wherein said crosslinked polymer comprises poly(2-acrylamido-2-methylpropanesulfonic acid).
8. The composition-of-matter of claim 1 , wherein said crosslinked polymer is crosslinked with N,N′-methylenebisacrylamide (MBAAm).
9. The composition-of-matter of claim 8 , wherein said crosslinking level ranges from 0.1 to 5 mol percent and said dry density is 0.15 g/cm 3 .
10. The composition-of-matter of claim 8 , wherein said crosslinking level ranges from 0.1 to 5 mol percent and said dry density is 0.30 g/cm 3 .
11. The composition-of-matter of claim 1 , wherein said aqueous external phase is a pre-polymerization mixture that comprises a plurality of monomers and crosslinking agents, wherein a mol percent of said crosslinking agents in said plurality of monomers and crosslinking agents ranges from 0.5 percent to 15 percent, and said organic internal phase constitutes from 60 percent to 95 percent of said high internal phase emulsion.
12. The composition-of-matter of claim 11 , wherein at least 85 percent of said plurality of monomers are ionizable monomers.
13. The composition-of-matter of claim 12 , wherein said ionizable monomers are selected from the group consisting of 2-acrylamido-2-methylpropane sulfonic acid (AMPS), 2-acrylamido-2-propanesulfonic acid, 1-acrylamido-1-propanesulfonic acid, 2-(methacryloyloxy)ethanesulfonic acid, 2-hydroxy-3-(2-propenyloxy)-propanesulfonic acid, 2-methacrylamido-2-methyl-1-propanesulfonic acid, 2-methyl-2-propene-1-sulfonic acid, 2-propene-1-sulfonic acid, 2-sulfoethyl acrylate, 2-sulfoethyl methacrylate, 3-methacrylamido-2-hydroxypropanesulfonic acid, 3-sulfopropyl acrylate, 3-sulfopropyl methacrylate, 3-sulfopropylacrylate, 3-sulfopropylmethacryflate, allyl sulfonic acid, allyloxybenzenesulfonic acid, methallyloxybenzenesulfonic acid, methallylsulfonic acid, phenylethenesulfonic acid, styrenesulfonic acid, sulfomethacrylamide, sulfomethylmethacrylamide, vinylsulfonic acid, and any salts thereof, and any combinations thereof.
14. The composition-of-matter of claim 11 , wherein said crosslinking agent is selected from the group consisting of N,N′-methylenebisacrylamide (MBAAm) ethylene glycol diacrylate, diethylene glycol diacrylate, N-(1-hydroxy-2,2-dimethoxyethyl)acrylamide, N,N′-(1,2-dihydroxyethylene)bisacrylamide, and any combination thereof.
15. The composition-of-matter of claim 11 , wherein said high internal phase emulsion further comprises a surfactant and an initiator.
16. The composition-of-matter of claim 15 , wherein said surfactant is a hydrophilic non-ionic surfactant.
17. A hydrogel comprising the composition-of-matter of claim 1 , and an aqueous medium absorbed therein.
18. The hydrogel of claim 17 , wherein said aqueous medium is selected from the group consisting of water, a solution of a water-soluble substance, waste-water, and urine.
19. An article of manufacture comprising the composition-of-matter of claim 1 .
20. The article of claim 19 , selected from the group consisting of a diaper, an incontinence garment, a fire-retardant material, a flood or spill control device, a fragrance carrier, a thermal pack, a liquid waste device, an ion-exchange matrix, a filter matrix, a water purification matrix, a surgical pad, a water retention device, a cosmetic product, a personal hygiene product, a personal care product, a grooming product and a wound dressing.