Exchange Membranes and Membrane Technology

General Requirements of Membranes for Chlor-Alkali Production 

Ion-exchange membranes for chlorine-caustic production should satisfy the following requirements,92 some of which tend to be conflicting with each other as will be elaborated in Section 6.2  

These requirements are met by a judicious choice and combination of the following properties of the membranes  

Membranes used in chlor-alkali operations are typically hydrolyzed copolymers of tetrafluoroethylene and perfluoro vinyl ether monomer containing an ion-exchange group, represented by the following general formula93  

Significant advances have been made in recent years to develop high-performance membranes for chlor-alkali cells by a judicious 

Dow Chemical Company recently announced new high-performance membranes employing only sulfonic add groups. With shorter suspended groups, it is claimed that the water of hydration is significantly reduced and the concentration of active sites on the membrane can be increased without creating channels for back migration of caustic. 

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