Polysulfone Supports for Composite Membranes

Early examples of cellulose acetate composite membranes used cellulose ester sheet materials as the porous underpinnings for the float-cast films. These sheet materials included (a) Loeb-Sourirajan asymmetric cellulose acetate mem- 

Polysulfone was recognized as a major improvement in the state-of-the-art of composite membranes at that time. But the broad scope of its usefulness was never fully appreciated until later. It has since become widely useful in its own right as an ultrafiltration membrane. It was subsequently included in a U.S. patent on ultrafiltration membranes by Michaels that issued in 1971.21 Concerning reverse osmosis membranes, it represented a key development that later enabled rapid progress to take place In noncellulosic composite membranes. 

---