Effects of Rotor Speed on Peroxide/Bismaleimide Cured Polypropylene/Nitrile Rubber Thermoplastic Vulcanizates (TPVs)

Elastomer thermoplastics are a class of polymeric materials that received industry attention due to the possibility of joining the elastic of elastomers with the thermoplastics processability. The synergistic properties are linked to the appropriate processing. This study evaluated the effect of rotor speed during polymer mixing and the dynamic vulcanization process of polypropylene and nitrile rubber blends. Bismaleimide was employed as multipurpose agent (crosslinking coagent for peroxide and compatibilizer). Morphology, mechanical properties, compression set and oil resistance tests were evaluated for compositions containing 50 and 70 PHR of elastomer. The compatibilization of TPV was realized by infrared spectroscopy. It was shown a compatibilizer effect and better dispersion, achieving the inversion phase, only studying the effect of processing conditions (rotor speed, addition sequence, additives), without any extra interfacial agent. There is a tendency to obtain better performance with decrease speed at dynamic vulcanization or/and at torque stabilization, mainly for blends with 50 PHR of rubber.