Influence of Fillers and Curing Systems on the Physico-Mechanical Properties and Stability of EPDM Vulcanizates

ABSTRACT

The thermal stability was investigated for ethylene propylene diene terpolymer (EPDM) rubber loaded with different white and black fillers, namely, kaolin, quartz, polyvinylchloride PVC, talc, graphite, medium thermal carbon black MT, semi reinforcing furnace black SRF, and high abrasion carbon black HAF. The fillers were added at a fixed level of 20 phr. Two curing systems were used, tetramethyl thiuram disulfide (TMTD) and sulfur/N-cyclohexyl-2-benzothiazyl sulfenamide (S/CBS). The effects of the curing system and type of filler on the physico-mechanical properties, before and after thermal aging were investigated. It was found that the vulcanizates cured with S/CBS system gave better physico-mechanical properties than the TMTD cured samples. However, TMTD cured EPDM has thermal stability performance superior to the other vulcanizing system.

Keywords:

• EPDM vulcanizates
• physico-mechanical properties
• thermal stability
• black fillers
• white fillers
• curing systems

Acknowledgments

The author thanks Professor M. N. Ismail for encouragement and useful discussions.

Notes

Phr: part per hundred parts of rubber.

Where: ML: minimum torque, MH: maximum torque, tc₉₀: Optimum cure time, ts₂: Scorch time, CRI: Cure rate index, TS: tensile strength, E: elongation at break, Q: equilibrium swelling.