A new method for producing porous polymer materials using carbon dioxide and a piston

A new method for manufacturing a porous polymer material is developed. In this method, nonwoven fabric sheets are placed in a high-pressure vessel and carbon dioxide is introduced at its vapor pressure. Then, stacked nonwoven fabric sheets are pressed by a piston along with liquefying carbon dioxide to produce a porous polymer material. Through holes were generated in the manufactured polymer material and scanning electron micrographs revealed that the polymer fibers largely remained intact. Surface observation after peeling off the sheet indicates that physical bonding by caulking to be the possible bonding mechanism. According to this technology, stacking sheets with different mesh roughness could enable the fabrication of a filter with a gradient in the mesh. Pressing an enzyme or a catalyst within the stacked fabric sheets can create a reaction cartridge. Drug-containing porous materials that can control the drug-release rate are also expected.