Porous materials, synthesis and characterization

Porous materials encloses a large number of materials with pore sizes depending on the application, The pore size can vary substantially: from a pore size as small as 5 Angstrom for materials used as the top layer of a multilayer nanofiltration membrane, to a ceramic foam structure with cell sizes of a few mm for dust filter applications. Obviously, the synthesis and characterization of materials with such a wide variety of pore sizes require different manufacturing routes and characterization techniques, In the past, sol-gel technology was applied for obtaining membrane layers with micro-or mesoporous pore sizes, The development of a Reaction Bonded processing route resulted in strong macroporous materials, characterized by a pore size range of 0.1 to 10 mum. Nowadays, we utilize different synthesis systems to produce ceramic foams with cell sizes as large as a few mm, In this contribution, the initial synthesis tests for ceramic foams, using gel casting, the hollow sphere method, a reaction bonded modified polyurethane replica technique and a Starch-gel casting method, are described, The obtained structures were analyzed by FESEM (Field Emission Scanning Electron Microscopy) and their mechanical behavior by 3 points bending tests.