A Novel Process for the Manufacture of Auxetic Foams and for Their re-Conversion to Conventional Form

A novel non-thermal process for the conversion of conventional open cell polymeric foams into auxetic foams by treatment with an organic solvent prior to subjecting them to a triaxial compression was described. Auxetic foam samples were manufactured from conventional open cell 30 ppi polyurethane foam using a novel chemo-mechanical process. Microstructure of the foams at high magnification show that the original foam is characterized by unit cells and the auxetic foams are characterized by a more complex geometry. It is also found that all the beneficial effects that are associated with the auxetic foams manufactured through the conventional thermo-mechanical method is also exhibited by our auxetic foams produced by the novel thermo-mechanical process. The similarities between various foams suggest that the re-conversion process, when applied to forms produced through the novel chem-mechanical method, is very effective.