Effect of processing agents on production of ion exchange membranes

Processing agents are commonly used in plastic processing to improve processability, stability of production, reduce drive torque and head pressure during homogenization and extrusion, reduce the cleaning intensity of the equipment, including lowering drooling on the extrusion die. Heterogeneous ion exchange membranes consist of a polymeric binder and an ion exchange resin. They are also produced by extrusion. Therefore, processing agents have been tested in the production of heterogeneous membranes. Three different types of processing agents were tested in the production of anion and cation exchange resin with two types of polyethylene binder. Processing agents were dosed at the expense of polymer binder in a concentration of 0.2–1.25 wt.%. The lowest and the highest recommended dose limit values of the processing agents were used in testing. Drive torque and head pressure were studied during homogenization and subsequent extrusion of the heterogeneous membrane. The most significant decrease of the head pressure and drive torque, about 20% or more, occurred with the use of a 1 wt.% Struktol agent, which is a fatty acid metal soap, amide. In addition, the preparation of the ion exchange membranes has been stabilized overall, the equipment can be easily cleaned after production, and the process temperature can be reduced. The physical and electrochemical properties of the manufactured ion exchange membranes were determined. Significant changes in properties of ion exchange membranes were not noted when processing agents were used.