Preparation of an ionomer elastomer by continuous sulfonation in an extruder and neutralization in static mixers

Rapid and efficient sulfonation of ethylene‐propylene terpolymer elastomer (EPDM) was achieved in a continuous melt mixing process. A mixture of sulfuric acid and acetic anhydride was used as the sulfonating agent. The reaction of EPDM polymer and the sulfonating agent was carried out in an extruder. It was shown that the continuous melt sulfonation of EPDM polymer may be used as an alternative to the batch solution methods previously reported for the preparation of sulfonated EPDM polymer. The extruder‐reactor method offers advantages of shorter process time, elimination of solvent handling hazards, and abatement of solvent removal and recovery problems.