Durability of poly(dimethylsiloxane) when exposed to chlorine gas

Abstract Highly crosslinked poly(dimethylsiloxane) (PDMS) is discussed as an alternative membrane material for the gas separation of highly concentrated chlorine gas (90–95 vol %) and oxygen, due to an initial high permeation for Cl 2 and a high selectivity of Cl 2 /O 2 . It was found that the separation properties of the PDMS membrane change over time upon exposure to aggressive chlorine gas; the flux will go down, and the material may even degrade if not appropriately prepared and protected. The PDMS was exposed to chlorine gas over 4 weeks in a glass chamber at both 30 and 60°C and analysed by (FTIR). The membranes were exposed to chlorine gas in a permeation cell with measurements of the permeability of N 2 , O 2 , and Cl 2 at regular intervals. The temperature range for the permeation measurements was 30–100°C, and the pressure difference over the membrane was ca. 2 bar. The time of exposure in the permeation cell was several weeks. The absorption of N 2 , O 2 , and Cl 2 in the PDMS at temperatures in the same range was also measured. This article discusses the durability of the highly crosslinked PDMS membrane following chlorine exposure. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2458–2470, 2002