Effect of Pore Forming Agent on the Porous Structure of Polydimethylsiloxine Membranes and Solvent Recovery by Low-pressure Membrane Filtration from Ink Solutions

Porous polydimethylsiloxine (PDMS) membranes were prepared using polyethylene glycol (PEG) or propylene glycol (PG) as pore forming agent (PFA). After the PDMS/PFA membranes were prepared, they were immersed in warm water to remove PFA from the membranes to prepare the PDMS porous membranes. Symmetric porous PDMS membrane was obtained when PEG was used as PFA. However, asymmetric porous membrane having a dense PDMS layer on one surface was prepared when PG was used as PFA. The porosity of the membranes increased with PFA content. The solvent permeation across the membranes was measured by low-pressure (0.2 MPa) driven filtration. Three kinds of ink solutions (green, blue and white) containing fine solid particle less than 360 μm and organic solvent were used as feed solutions. The permeation increased with increasing the PFA content. The solid particle weight concentrations in ink solutions were about 10 wt% , however, almost pure solvent was obtained for all the ink solutions by the filtration when the membranes prepared using PG as PFA: the solid particle weight concentration was less than 1 wt% in permeate.