Method for inflating or deflating closed cell foams

Claim 1

METHOD FOR OSMOTICALLY EFFECTING A NET CHANGE IN THE DENSITY OF A SYNTHETIC, HIGH MOLECULAR WEIGHT, POLYMERIC CELLULAR STRUCTURE HAVING A DENSITY OF 1% TO 75% OF THE DENSITY OF THE POLYMER IN SOLID NON-EXPANDED FORM, SAID CELLULAR STRUCTURE HAVING A MAJOR PROPORTION OF CLOSED CELLS DEFINED BY GAS PERMEABLE WALLS AND BEING CHARACTERIZED IN THAT IN EXPANDED CONDITION IT IS REVERSIBLY YIELDABLE SUCH THAT SUBSTANTIAL DEFORMATION OCCURS UNDER INTERNAL-EXTERNAL PRESSURE DIFFERENTIALS, WHICH METHOD COMPRISES THE STEPS OF (A) IMMERSING SAID CELLULAR STRUCTURE AT A PRESSURE NO LESS THAN ABOUT ATMOSPHERIC IN A FLUID PERMETAING AGENT CAPABLE OF PERMEATING THE SAID CELL WALLS, THEREBY EFFECTING DIFFUSION OF THE SAID AGENT INTO THE CELLS TO ESTABLISH AN INTERNAL PARTIAL PRESSURE OF SAID AGENT, AND SUBSEQUENTLY (B) SUBJECTING THE THUSLY TREATED STRUCTURE TO A GASEOUS ATMOSPHERE ALSO CAPABLE OF PERMEATING THE SAID CELL WALLS BUT WHICH HAS A DIFFERENT PERMEABILITY RATE THROUGH THE CELL WALLS THAN DOES SAID AGENT, FURTHER PROVIDED THAT IF SAID GASEOUS ATMOSPHERE IS MORE PERMEANT TO THE WALLS THAN IS SAID AGENT THEN THE EXTERNAL PARTIAL PRESSURE OF THE ATMOSPHERE IS GREATER THAN THER INTERNAL PARTIAL PRESSURE THEREOF WHEREAS IF SAID GASEOUS ATMOSPHERE IS LESS PERMEANT TO THE WALLS THAN IS SAID AGENT THEN THE EXTERNAL PARTIAL PRESSURE OF SAID AGENT IS LOWER THAN THE INTERNAL PARTIAL PRESSURE THEREOF THEREBY EFFECTING A NET CHANGE IN THE QUANTITY OF FLUID WITHIN SAID CLOSED CELLS.