Dynamically vulcanized blends of UHM-EPDM and polypropylene: Role of nano-fillers improving thermal and rheological properties

The effect of the addition of various types of nano-fillers on the viscoelastic properties of the dynamically vulcanized ultra-high molecular weight EPDM (UHM-EPDM)/Polypropylene (PP) was studied in details. The authors have studied the molten state viscoelastic properties at 180 °C by dynamic strain sweep (SS) and also stress relaxation (SR) through Rubber process Analyzer (RPA). The results of the SS and SR indicates that due the addition of the nano-silica to the blends resulting higher Storage modulus (Gʹ) and slower rate of relaxation than the pristine blend and nano-clay added blends. In the parallel plate rheometer frequency sweep study (FS), authors have noticed that nano-silica added blends are showing similar trends like SS study (in RPA) and all the blends are following pseudoplastic type flow behaviour. In the Cole-Cole plot, it is found that there is no semi-circular nature of the ηʹʹ vs ηʹ curve, and it indicates the immiscibility of the blends. In the thermal characterization, it is observed that there is a change in temperature in the thermal degradation study (TGA) about ̴ 5 °C and as the nano-filler amount are increasing the degradation temperature also improving. This special type of UHM-EPDM based TPVs exhibit superior physico-mechanical properties over conventional EPDM based TPVs and in presence of nano-fillers, they show even better physical properties. These newly developed TPVNs can be applied in aesthetic seals/strips, smaller injection moulded parts and 2K-moulds with PP in automotive.