Unlubricated rolling and sliding wear against steel of carbon‐black‐reinforced and in situ cured polyurethane containing ethylene/propylene/diene rubber compounds

The dry rolling and sliding friction and wear of ethylene/propylene/diene rubber containing carbon black and in situ cured polyurethane (EPDM+PUR_CB) were studied. For rolling and sliding tests against steel counterparts, different experimental conditions and tribotests were selected. The apparent network properties and phase structures of the rubbers were derived from dynamic mechanical thermal analysis and atomic force microscopy results. It was concluded that in EPDM+PUR_CB, both rubber phases, present in a 1 : 1 ratio, were continuous (interpenetrating network). The coefficient of friction (COF), specific wear rate (W_s), and heat development during the tribotests were determined. The carbon black and polyurethane contents did not much influence the COF in rolling wear tests. W_s of the ethylene/propylene/diene rubber containing carbon black went through a minimum as a function of the carbon black content. W_s of the EPDM+PUR_CB compounds decreased monotonously with an increasing amount of carbon black. The incorporation of polyurethane into the ethylene/propylene/diene rubber compounds decreased the resistance to rolling wear markedly. With carbon black filling of the ethylene/propylene/diene rubber–polyurethane compound, the COF and W_s increased and dramatically decreased, respectively, under sliding wear. The wear mechanisms were inspected with scanning electron microscopy and discussed as a function of recipe modifications and changes in the testing conditions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010