Vulcanization and properties of hydrogenated nitrile rubber/nitrile rubber blends

The HNBR/NBR blends were prepared at ratios of 100/0, 90/10, 80/20 and 70/30 (wt%). The compounds by using a two-roll mixing mill at various ratios filled with two types of carbon black loading, GPF N-660 and SRF N-774 (fixed at 50 phr) were cured by three vulcanization systems: conventional vulcanization, efficient vulcanization and peroxide vulcanization. From the cure characteristics, the HNBR/NBR blends at 20 30%NBR cured by peroxide system exhibited maximum torque and the blends cured by EV system showed the lowest. The HNBR/NBR blends cured by peroxide system also exhibited the higher 100%modulus and tensile strength with lower elongation at break than that cured by sulfur system. The N-660 filled vulcanizate exhibited the better mechanical properties than filled N-774 vulcanizate. Thermal aging, ozone and oil resistance properties of HNBR/NBR blends decreased with increasing the NBR content. The HNBR/NBR blends cured by peroxide system showed the better heat stability than that cured by sulfur system. The cost of the HNBR/NBR blend using peroxide curing systems which have the superior mechanical properties showed the lowest cost of compound.