# US 10,369,248 B2 · Porous polymer composites

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- Number: US 10,369,248 B2
- Document ID: US10369248B2
- Status: Granted
- Kind: B2
- Application number: 14/445,089
- Filed: 2014-07-29
- Published: 2016-02-04
- Granted: 2019-08-06
- Earliest claimed: 2014-07-29
- Assignees: The United States of America as represented by the Secretary of the Army
- Applicants: U.S. Army Research Laboratory ATTN: RDRL-LOC-I
- Inventors: Randy A. Mrozek; Joseph L. Lenhart; Michael C. Berg; Eric J. Robinette
- Web page: https://patentgrep.com/patent/US10369248B2

## CPC

- A61L 24/0036: {Porous materials, e.g. foams or sponges}
- A61L 24/0015: {Medicaments; Biocides}
- C08J 9/26: by elimination of a solid phase from a macromolecular composition or article, e.g. leaching out
- C08J 9/28: by elimination of a liquid phase from a macromolecular composition or article, e.g. drying of coagulum
- A61L 2300/418: Agents promoting blood coagulation, blood-clotting agents, embolising agents
- A61L 2400/04: Materials for stopping bleeding
- A61L 2400/08: Methods for forming porous structures using a negative form which is filled and then removed by pyrolysis or dissolution
- C08J 2201/0543: the non-solvent being organic
- C08J 2207/10: Medical applications, e.g. biocompatible scaffolds
- C08J 2207/12: Sanitary use, e.g. diapers, napkins or bandages
- C08J 2353/02: of vinyl aromatic monomers and conjugated dienes
- A61L: METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES (preservation of bodies or disinfecting characterised by the agents employed A01N; preserving, e.g. sterilising, food or foodstuffs A23; preparations for medical, dental or toiletry purposes A61K)
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)

## Abstract

Porous polymer composites and methods of preparing porous polymer composites are provided herein. In some embodiments, a method for preparing porous polymer composites may include mixing a first polymer with a solvent and a particulate filler to form a first polymer composition, wherein the amount of particulate filler in the first polymer composition is below a mechanical percolation threshold; and removing the solvent from the first polymer composition to concentrate the first polymer and particulate filler into a second polymer composition having a porous structure, wherein the particulate filler concentration in the second polymer composition is increased above the mechanical percolation threshold during solvent removal.

## Claims

### Claim 1

A method of forming a porous polymer composition without the use of phase separation, a poragen or a blowing agent, comprising:
mixing a first polymer with a first solvent that is miscible with said first polymer and a particulate filler at a first concentration to form a first polymer composition, wherein the first concentration of particulate filler in the first polymer composition is below a mechanical percolation threshold;
removing the first solvent from the first polymer composition to concentrate the first polymer and the particulate filler into a second polymer composition having a porous structure, wherein the particulate filler concentration in the second polymer composition is increased above the first concentration and the mechanical percolation threshold during first solvent removal;
wherein the first polymer is poly(styrene-b-ethylene-co-butylene-b-styrene); and
further wherein removing the first solvent from the polymer composition concentrates that filler in the first polymer above the mechanical percolation threshold of the filler in the first polymer forcing fibrils to form between filler particles and the produces a porous polymer composition with an interconnected pore structure that provides mass transport through the polymer composition without the use of phase separation, a poragen or a blowing agent.

### Claim 2 (depends on 1)

The method of claim 1, wherein the particulate filler concentration in the first polymer composition is about 2 volume % to about 55 volume %.

### Claim 3 (depends on 1)

The method of claim 1, wherein the particulate filler concentration in the second polymer composition is about 3 volume % to about 95 volume % relative to a total volume of solids in the second polymer composition.

### Claim 4 (depends on 1)

The method of claim 1, wherein the first solvent is removed by at least one of evaporation or extraction with a secondary solvent.

### Claim 5 (depends on 1)

The method of claim 1, further comprising backfilling the second polymer composition with a second polymer.

### Claim 6 (depends on 1)

The method of claim 1, further comprising removing at least some of the particulate filler from the second polymer composition.

### Claim 7 (depends on 6)

The method of claim 6, further comprising removing the particulate filler from the second polymer composition by at least one of degrading the particulate filler through the application of an external stimulus to the second polymer composition or dissolving the particulate filler for in a first solvent which will not dissolve the first polymer.

### Claim 8 (depends on 1)

The method of claim 1, further comprising extruding the first polymer composition into an elongated strand having a particulate filler-loaded outer shell circumscribing a particulate filler-loaded inner core.

### Claim 9 (depends on 8)

The method of claim 8, further comprising preferentially removing at least some of the particulate filler from the outer shell while maintaining a particulate filler-loaded inner core.

### Claim 10 (depends on 1)

The method of claim 1, further comprising mixing chemical additives into the first polymer composition.

### Claim 11 (depends on 10)

The method of claim 10, wherein the chemical additives further comprise at least one of proteins, dopamine, catechol, glutaraldehyde, peroxide, clotting agents, therapeutic agents, or chitosan.

### Claim 12

A method of forming a hemorrhage control product without the use of phase separation, a poragen or a blowing agent, comprising:
mixing a first polymer with a first solvent that is miscible with said first polymer and a particulate filler at a first concentration to form a first polymer composition, wherein the first concentration of particulate filler is below a mechanical percolation threshold;
forming the first polymer composition into a first geometry having a particle filler-loaded outer shell circumscribing a particle filler-loaded inner core; and
removing the first solvent from the first polymer composition to concentrate the particulate filler into a second polymer composition having a porous structure, wherein the particulate filler concentration in the second polymer composition is increased above the first concentration and the mechanical percolation threshold during first solvent removal
wherein the first polymer is poly(styrene-b-ethylene-co-butylene-b-styrene).

### Claim 13 (depends on 12)

The method of claim 12, further comprising preferentially removing the particulate filler by degrading the particulate filler through the application of an external stimulus to the porous second polymer composition.

### Claim 14 (depends on 13)

The method of claim 13, further comprising preferentially removing the particulate filler from the outer shell by dissolving the particulate filler for a first period of time in a second solvent which will not dissolve the first polymer.

### Claim 15 (depends on 12)

The method of claim 12, further comprising mixing at least two of proteins, catechol, glutaraldehyde, peroxide, clotting agents, therapeutic agents, or chitosan into the first polymer composition.

### Claim 16 (depends on 1)

An article, made by the method of claim 1.

### Claim 17 (depends on 16)

The article of claim 16, further comprising at least two of proteins, dopamine, catechol, glutaraldehyde, peroxide, clotting agents, therapeutic agents, biocompatible foaming agents, or chitosan bonded to an outer surface of the porous polymer outer shell to promote wound healing.

### Claim 18 (depends on 16)

The article of claim 16, further comprising a thermosetting adhesive bonded to the porous polymer outer shell to promote adhesive bonding.

### Claim 19 (depends on 1)

The method of claim 1, wherein the first solvent is an oil that that is miscible with said first polymer.

### Claim 20 (depends on 1)

The method of claim 1, wherein the first solvent is a mineral oil that that is miscible with said first polymer.

### Claim 21 (depends on 1)

The method of claim 1, further comprising removing the first solvent with a second solvent that has high solubility with the first solvent but without swelling the first polymer composition.