ELECTRICAL AND PHYSICAL-PROPERTIES OF ETHYLENE-PROPYLENE-DIENE MONOMER (EPDM) RUBBER LOADED WITH SEMI-REINFORCING FURNACE BLACK

The physico-mechanical properties have been investigated of ethylene-p ropylene-diene monomer (EPDM) rubber samples loaded with semi-reinforc ing furnace black (SRF) in quantities up to 60 phr. It is shown that i ncrease of SRF content increases the tensile strength and decreases th e elongation at break and equilibrium swelling. The permittivity epsil on' and the dielectric loss epsilon'' for these samples were determine d in the frequency range 100 Hz to 10 MHz. epsilon' was found to incre ase with increasing carbon content and showed anomalous dispersion. At a certain concentration of SRF black, an abrupt increase in epsilon' and epsilon'' was noticed. This could be ascribed to some sort of inte raction between the rubber and the SRF at higher concentration. The ab sorption spectra were analysed into three Frohlich terms for both unlo aded and loaded samples. The first term, in the lower frequency range, could be attributed to the Maxwell-Wagner effect, while the second an d third terms in the higher frequency range may be due to the orientat ion of the large and small aggregates caused by movement of the main c hain. The samples under investigation were subjected to thermal ageing for different periods of time, the measurements were reinvestigated a nd the data obtained interpreted.