Membran mit verbesserter Gaspermeabilitaet und Verfahren zu ihrer Herstellung

摘要

1331068 Hollow fibres DOW CHEMICAL CO 4 Dec 1970 [4 Dec 1969] 57732/70 Heading B5B A gas permeable permselective membrane, preferably in the form of one or more hollow fibres, comprises a dispersion of a thermoplastic resin having an oxygen permeability of at least 0À5 Î 10-10 c.c. cm./cm.2 sec. cm. Hg at 37‹ C., and 10 to 75 weight per cent of an organosiloxane, a hydrocarbon rubber extender oil or mixture thereof, the oil and siloxane being compatible with the thermoplastic resin at or above its melting temperature and incompatible therewith at ambient temperatures. The thermoplastic resin is, suitably, an α-olefin polymer or interpolymer prepared from an olefin with 2 to 10 carbon atoms having alkyl side chains, a preferred polymer is poly-4-methyl-pentene-1. The polysiloxane, which is preferably a low viscosity liquid at ambient temperatures, suitably contains an average unit of formula R n SiO 4-n where n has an average value from #2 0À9 to 3 and R is a monovalent hydrocarbon or halogenated hydrocarbon radical. The preferred rubber extender oil is a polybutene oil. The membrane may be prepared by extruding a melt containing a ratio by weight of siloxane to thermoplastic resin of between 1 : 1 and 1 : 5 and an oil to resin ratio of between 0À8 : 1 to 1À5 : 1. Alternatively hollow fibres may be prepared containing thermoplastic resin and hydrocarbon oil and these may be impregnated with a polyorganosiloxane, suitably polydimethylsiloxane, by leaching out the extender oil with a solvent (e.g. xylene) which is a non- solvent for the thermoplastic resin and dipping the leached fibres in the siloxane. The membrane may be exposed to high energy radiation, e.g. X-rays, to cross-link the polyorganosiloxane.