Mechanical reticulation of polymeric-based closed cell foams

1. A system comprising:

a polyurethane shape memory polymer (SMP) foam;

first and second cells, included in the SMP foam, which directly contact each other;

wherein (a)(i) the first and second cells share and directly contact a ring of struts that provides structural support for the first and second cells, (a)(ii) a membrane directly contacts the ring of struts, and (a)(iii) the membrane is partially reticulated but not fully reticulated;

wherein the partially reticulated membrane includes: (b)(i) a void that forms a fluid path between the first and second cells, (b)(ii) an interface, between the partially reticulated membrane and the void, which is rough and uneven;

wherein the SMP foam includes a reaction product of triethanolamine (TEA) and hexamethylene diisocyanate (HDI).

2. The system of claim 1 , wherein the interface is not chemically etched.

3. The system of claim 1 , wherein the SMP foam includes cells, including the first and second cells, which are anisotropic in shape and have unequal major and minor axes.

4. The system of claim 1 , wherein:

the ring of struts defines an outer perimeter of the membrane and the void defines an inner perimeter of the membrane;

an outer membrane area for the membrane is an area bounded by the outer perimeter defining an area of the membrane before reticulation;

a void area is an area bounded by the inner perimeter defining an area of the void; and

the void area is between 25% and 75% of the outer membrane area.

5. The system of claim 4 , wherein:

the interface defines a protuberance of the membrane that protrudes away from the ring of struts and toward a central region of the void; and

the ring of struts forms a complete ring that is unbroken.

6. The system of claim 1 , wherein the SMP foam comprises:

a first contiguous fluid path between at least 5 cells and formed along an axis that is generally parallel to a major axis of the foam; and

a second contiguous fluid path between an additional at least 5 cells and formed along an additional axis that is generally parallel to the major axis;

wherein a third axis, generally parallel to a minor axis of the foam, intersects at least one of the at least 5 cells and at least one of the additional at least 5 cells.

7. The system of claim 6 , wherein: (a) a majority of reticulated membranes of the SMP foam include voids and interfaces with those voids, and (b) the interfaces are rough and uneven.

8. A system comprising:

a polyurethane shape memory polymer (SMP) foam;

first and second cells, included in the SMP foam, which directly contact each other;

wherein (a)(i) the first and second cells share and directly contact a ring of struts that provides structural support for the first and second cells, (a)(ii) a membrane directly contacts the ring of struts, and (a)(iii) the membrane is partially reticulated but not fully reticulated;

wherein the partially reticulated membrane includes: (b)(i) a void that forms a fluid path between the first and second cells, (b)(ii) an interface, between the partially reticulated membrane and the void, which is rough and uneven;

wherein the SMP foam includes a reaction product of triethanolamine (TEA) and trimethyl hexamethylene diisocyanate (TMHDI).

9. The system of claim 8 , wherein the interface is not chemically etched.

10. The system of claim 8 , wherein the SMP foam includes cells, including the first and second cells, which are anisotropic in shape and have unequal major and minor axes.

11. The system of claim 8 , wherein:

the ring of struts defines an outer perimeter of the membrane and the void defines an inner perimeter of the membrane;

an outer membrane area for the membrane is an area bounded by the outer perimeter defining an area of the membrane before reticulation;

a void area is an area bounded by the inner perimeter defining an area of the void;

and the void area is between 25% and 75% of the outer membrane area.

12. The system of claim 11 , wherein:

the interface defines a protuberance of the membrane that protrudes away from the ring of struts and toward a central region of the void; and

the ring of struts forms a complete ring that is unbroken.

13. The system of claim 8 , wherein the SMP foam comprises:

a first contiguous fluid path between at least 5 cells and formed along an axis that is generally parallel to a major axis of the foam; and

a second contiguous fluid path between an additional at least 5 cells and formed along an additional axis that is generally parallel to the major axis;

wherein a third axis, generally parallel to a minor axis of the foam, intersects at least one of the at least 5 cells and at least one of the additional at least 5 cells.

14. The system of claim 13 , wherein: (a) a majority of reticulated membranes of the SMP foam include voids and interfaces with those voids, and (b) the interfaces are rough and uneven.

15. A system comprising:

a polyurethane shape memory polymer (SMP) foam;

first and second cells, included in the SMP foam, which directly contact each other;

wherein (a)(i) the first and second cells share and directly contact a ring of struts that provides structural support for the first and second cells, (a)(ii) a membrane directly contacts the ring of struts, and (a)(iii) the membrane is partially reticulated but not fully reticulated;

wherein the partially reticulated membrane includes: (b)(i) a void that forms a fluid path between the first and second cells, (b)(ii) an interface, between the partially reticulated membrane and the void, which is rough and uneven;

wherein the SMP foam includes a reaction product of glycerol and hexamethylene diisocyanate (HDI).

16. The system of claim 15 , wherein the interface is not chemically etched.

17. The system of claim 15 , wherein the SMP foam includes cells, including the first and second cells, which are anisotropic in shape and have unequal major and minor axes.

18. The system of claim 15 , wherein:

the ring of struts defines an outer perimeter of the membrane and the void defines an inner perimeter of the membrane;

an outer membrane area for the membrane is an area bounded by the outer perimeter defining an area of the membrane before reticulation;

a void area is an area bounded by the inner perimeter defining an area of the void;

and the void area is between 25% and 75% of the outer membrane area.

19. The system of claim 18 , wherein:

the interface defines a protuberance of the membrane that protrudes away from the ring of struts and toward a central region of the void; and

the ring of struts forms a complete ring that is unbroken.

20. The system of claim 15 , wherein the SMP foam comprises:

a first contiguous fluid path between at least 5 cells and formed along an axis that is generally parallel to a major axis of the foam; and

a second contiguous fluid path between an additional at least 5 cells and formed along an additional axis that is generally parallel to the major axis;

wherein a third axis, generally parallel to a minor axis of the foam, intersects at least one of the at least 5 cells and at least one of the additional at least 5 cells.

21. The system of claim 20 , wherein: (a) a majority of reticulated membranes of the SMP foam include voids and interfaces with those voids, and (b) the interfaces are rough and uneven.