Ethylene-propylene-diene monomer/polytetrafluorethylene (EPDM/PTFE) composites based on EPDM and electron beam irradiated PTFE powders (MS-II, MS-III, and MS-V, with mean diameter 5 mu m, 1 mu m, and 0.1 mu m, respectively) were prepared by a mechanical compounding technique. The curing characteristics, morphologies, mechanical properties, and abrasion behaviors of these composites were investigated. The curing measurements indicated that the addition of lower loading of MS-III or MS-V enhanced the lubrication of EPDM compounds and delayed the curing process. The morphological structure of the composites demonstrated that the MS-III and MS-V were uniformly dispersed in EPDM matrix and the efficient polymer-filler interfacial interactions were constructed. In comparison with EPDM/MS-II and EPDM/MS-III, EPDM/MS-V exhibited outstanding tensile strength, tear strength, elongation at break, and abrasion resistance due to the nanometer particle dimension and good dispersion of MS-V as well as the stronger interfacial interactions between MS-V and the EPDM matrix. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 3734-3740, 2012