A SELECTIVE SILICON-BASED MEMBRANE FORMED BY PYROLYSIS OF SILICON RESIN

A new, highly selective silicon-based membrane was developed by pyroly zing a thermosetting silicon resin precursor in two steps. The pyrolys is step was performed under an inert gas in the range of 800 to 950 de grees C, The activation step was conducted at the same temperature as the first step, Oxygen content in the activation gas was located betwe en 0.5 and 1.0%, The crosslinking density and the matrix structure of the polymeric precursor were important factors for the permeable chara cteristics of the resulting pyrolysis membrane, The average selectivit y was 5 to 10 times those of a pyrolysis membrane from silicon rubber, Additives in the precursor had significant effects on toughness and s tability of the resulting membrane. By varying the additive content in the precursor, silicon-based pyrolysis membranes with different stabi lities in air were obtained.