Effect of vulcanization technique on the physical properties of silica-filled EPDM rubber

The present study aims to enhance EPDM rubber-silica interaction by employing a special technique called Two-Stage Vulcanization, with the help of a multifunctional rubber additive, bis diisopropyl thiophosphoryl disulfide (DIPDIS). In this process EPDM rubber was heated along with rubber additives up to the time just before the commencement of cure and then filler was incorporated to the preheated rubber to get the final mix. The efficiency of this novel technique is evaluated by the enhancement of physical properties of the silica-filled vulcanizates. This novel technique is also employed to investigate the effect of a silane-coupling agent, viz., bis (3-triethoxy silyl propyl) tetrasulphide (TESPT), in addition to DIPDIS, on the rubber-filler interaction. The positive role of this technique in enhancing the rubber-filler interaction is evidenced by the dynamic mechanical analysis and scanning electron microscopy. (c) 2005 Wiley Periodicals, Inc.