These are controlled cell foam materials, where the cell windows of conventional grades have been exploded out, to create a 100% open cell network. This network, becomes a very good filtration medium where the foam porosity can be controlled to give grades of different pore sizes. These sizes vary from 10ppi (coarse) to 90ppi (fine). There are two basic grades of PU foams ether (good for water filters) or ester (for air filtration). These foams can be impregnated with various substrates to improve the performance and efficiency of the filter foam.
New developments are reticulated foam with a hydrophilic foam impregnated into it. The hydrophilic foam can have active ingredients incorporated or potential developments could be the immobilization of enzymes to create a unique filter medium to remove specific chemicals. More information on Reticulated PU Foam