In this work a new approach to grind polymer ion exchange particles smaller than one micrometer under ambient conditions is presented. Detailed studies have been performed on the grinding of commercially available porous polymer ion exchange particles with a median size of several hundred microns. Therefore grinding experiments have been performed, operated in a double-stage process, starting in a ceramic ball mill and continued in a stirred media mill. The ground material was analyzed and characterized applying established measuring methods to obtain characteristic properties. The results show that it is possible to grind porous polymers in a stirred media mill down to a few hundred nanometers. The ion exchange capacity of the particles remains unaffected during the grinding process. (C) 2015 Elsevier B.V. All rights reserved.