What is claimed is:
1. A pressure vessel comprising
a wall circumferentially enclosing an open volume capable of being filled with a fluid, wherein the wall comprises an interior surface adjacent the open volume and an exterior surface opposite the interior surface, a first end, a second end, and an axial direction;
wherein the wall comprises a composite layer comprising a resin system impregnated with fibers and a plurality of surface-modified nanoparticles, and further wherein the surface-modified nanoparticles comprise a core comprising calcite and a surface-modifying agent ionically associated with the core.
2. The pressure vessel of claim 1 , wherein the pressure vessel wherein at least one composite layer comprises fibers aligned at angle of greater than 70 degrees relative to the axial direction.
3. The pressure vessel of claim 2 , wherein at least one composite layer comprises fibers aligned at angle of no greater than 40 degrees relative to the axial direction.
4. The pressure vessel of claim 1 , wherein at least one composite layer comprises fibers aligned at angle of between 40 and 70 degrees, inclusive, relative to the axial direction.
5. The pressure vessel according to claim 1 , further comprising a first cap extending from the wall adjacent the first end, further enclosing the open volume.
6. The pressure vessel of claim 5 , further comprising a second cap extending from the wall adjacent the second end, isolating the open volume from the ambient environment surrounding the pressure vessel.
7. The pressure vessel according to claim 1 , wherein a cross section of the wall perpendicular to the axial direction is elliptical.
8. The pressure vessel of claim 1 , wherein the pressure vessel is ellipsoidal.
9. The pressure vessel according to claim 1 , wherein the curable matrix resin comprises an epoxy.
10. The pressure vessel according to claim 1 , wherein the resin system further comprises a rubber toughener.
11. The pressure vessel according to claim 1 , wherein the wall further comprises a liner having an interior surface adjacent the open space and an exterior surface, wherein the composite layer is adjacent the exterior surface of the liner.
12. The pressure vessel of claim 11 , wherein the liner comprises at least one a metal and a polymer.
13. The pressure vessel according claim 1 , wherein the open volume contains a fluid at an absolute pressure of at least 10 MPa.
14. The pressure vessel according to claim 1 , wherein the open volume contains a fluid at an absolute pressure of at least 30 MPa.
15. The pressure vessel according to claim 1 , wherein the open volume contains a fluid at an absolute pressure of at least 80 MPa.
16. The pressure vessel according to claim 10 , wherein the rubber toughener comprises a coreshell rubber.
17. The pressure vessel according to claim 1 , wherein the surface modifying agent comprises a phosphonic acid group.
18. The pressure vessel according to claim 1 , wherein the surface modifying agent comprises a sulfonic acid group.
19. The pressure vessel according to claim 1 , wherein the surface modifying agent comprises a binding group having a bond energy to the core of at least 0.6 electron volts.