| 摘要 |
PROBLEM TO BE SOLVED: To realize high heat resistance, a high gas permeation speed and high gas selectivity and to facilitate production by allowing a peak showing a three-membered ring and a four-membred ring to be present in Raman analysis and setting the strength ratio of three-membered ring/four-membered ring to a specific range. SOLUTION: A porous silica membrane useful as a separation membrane is obtained within a short time by simple operation wherein a porous ceramics base material is coated with a soln. of polysilazane having a skeleton composed of a structure unit represented by formula (wherein R is an alkyl group and n and m show a mol ratio to take a range of n:m=100:0-30:70) and the coated base material is dried or baked. In Raman analysis, a peak showing a three- membered ring (600p20cm<-1> ) and a four-membered ring (490±20cm<-1> ) is allowed to be present and a (three-membered ring)/(four-membered ring)strength ratio is set to 0.1-10.0. By this method, high heat resistance, a high gas permeation speed and high gas selectivity can be realized and production can be made easy.
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