Horikaaboneetomakuoyobisonoseizo

摘要

1500937 Polycarbonate polyether copolymer membranes UNITED STATES GOVERNMENT OF 28 Feb 1975 [26 March 1974] 8359/75 Heading B5B The membranes are formed by casting on to a substrate a solution of a polyether-polycarbonate block copolymer containing 5-35% by wt. of polyether component and a watermiscible organic solvent together with a co-solvent acting as a swelling agent, partially drying the film, immersing the film in water to form a gelled membrane and stripping the gelled membrane from the substrate. The copolymer has a mol. wt. of 50,000 to 750,000 and is prepared from bisphenol A and polyethylene glycol (mol. wt. 600-6000). The casting solution is preferably a 1-20% by wt. solution in 1,3-dioxolane containing 10-75% by wt. of the copolymer of a co-solvent such as DMSO, DMF or pyridine.