Effects of Compounding Procedure on Morphology Development, Melt Rheology, and Mechanical Properties of Nanoclay-Reinforced Dynamically Vulcanized EPDM/Polypropylene Thermoplastic Vulcanizates

New nanocomposite thermoplastic vulcanizates (TPVs) comprising dynamically crosslinked nanoscale EPDM rubber particles dispersed throughout the polypropylene (PP) matrix have been prepared by both batch and continuous melt blending of PP with EPDM in the presence of vulcanizing ingredients, nanoclay and maleated EPDM (EPDM-g-MA) as compatibilizer. X-ray diffraction, linear melt viscoelastic measurement, and tensile mechanical behavior results revealed that the developed microstructure is strongly affected by the type of the melt compounding process as well as the route of material feeding. When EPDM phase was precompounded with a vulcanizing agent, nanoclay, and EPDM-g-MA prior to the melt blending with PP, not only nanosize crosslinked rubber particles appeared uniformly throughout the PP continuous phase, but also the melt blending leads to the significant enhancement of the mechanical properties compared with counterpart samples prepared by one-step melt mixing process. Also better dispersion of nano layers in the rubber compound before melt blending with PP results in higher mechanical properties of the resulted TPV. (C) 2016 Society of Plastics Engineers