Tailoring the pore-size distribution of high surface area microporous silicon imidonitrides by control of precursor composition

High surface area, microporous, amorphous silicon imidonitride, characteriz ed by infrared spectroscopy, MAS Si-29 NMR, surface area and porosity measu rements has been prepared by thermal ammonolysis of both co-oligomers of me thylsilazane and dimethylsilazanes and of block copolymers of butadiene and methylsilazane. Variation of the organic content of the silazane is a mean s of controlling the surface area of the resulting solid and tailoring the pore-size distribution of the final silicon imidonitride. The resulting mat erials have pore-size distributions showing a maximum in the range associat ed with wide-pore zeolites. (C) 1999 Elsevier Science B.V. All rights reser ved.