Physical and tribological properties of PTFE micropowder-filled EPDM rubber

The physical and tribological properties of ethylene-propylene-diene-rubber (EPDM) filled with polytetrafluoroethylene (PTFE) micropowders, i.e. MP1100 and MP1200 having chemically similar but distinctive microstructural morphology have been investigated. EPDM-PTFE micropowder blends filled with MP1200 having a solid granular structure, showed poor tensile strength and elongation at break but significantly improved tribological properties. It attained both the lowest steady-state friction coefficient and specific wear rate. However, EPDM-PTFE blends containing a fine agglomerated PTFE micropowder of MP1100 showed enhanced physical properties. Its increasing tensile strength and elongation at break with PTFE micropowder loading compared to MP1200-filled EPDM blend was essentially due to its characteristic morphology, which enhanced its dispersion and compatibility with EPDM. It showed specific wear rate similar to MP1200-filled EPDM but resulted in high friction coefficient. Scanning electron microscopy (SEM) of the PTFE micropowders and the corresponding PTFE micropowder-filled EPDM blends suggest that agglomerates morphology, dispersion and interfacial compatibility with EPDM are the key factors influencing physical and tribological properties of these compounds.