Hari P. Nadella

MORPHOLOGY AND RHEOLOGY OF NONREACTIVE AND REACTIVE EPDM/PP BLENDS IN TRANSIENT SHEAR FLOW: PLASTICIZED VERSUS NONPLASTICIZED BLENDS

Abstract Both nonplasticized and plasticized ethylene-propylene-diene-terpolymer/polypropylene (EPDM/PP) based thermoplastic elastomers (TPEs) were prepared in the presence and absence of a curing system (i.e., reactive vs nonreactive TPEs). The nonlinear viscoelastic behavior and morphology evolution of these blends were investigated through single and multiple start-up transient experiments to find out the effects of composition, plasticizer, and the presence of the curing system in a homogeneous shear flow field. Due to the highly elastic nature of the elastomeric component, the shear rate was set to 0.1 s−1 and in the case of multiple start-up experiments a 10 min rest time was set between consecutive shearing cycles. The specific interfacial area (Q) of the TPEs was analyzed prior and after shearing and subsequently correlated to the corresponding rheological response of these blends. The magnitude and the width of the stress overshoot were correlated to the morphology of the blends, elastomer conten...

Rheology/Morphology Relationship of Immiscible EPDM/PP Based Thermoplastic Elastomer Blends

The rheological and morphological properties of non‐plasticized/plasticized EPDM/PP based thermoplastic elastomers (TPEs) have been investigated. The addition of a plasticizer reduced the rheological properties of both components and their blends and increased their deformability. Complex morphological features (e.g., specific interfacial area and its orientation) of these blends have been analyzed after multiple start‐up experiments using atomic force microscopy.