Rheological properties of incompatible blends of two elastomers

Mold flows and melt viscosities of an incompatible bi-component EPDM and “Viton” fluoroelastormer system were examined. A marked reduction in the melt viscosities of either component was observed when a small amount of the other component was present. It was speculated that the phenomenon was a result of a slippage between the polymer and the coated capillary surface due to the presence of a minor amount of the incompatible polymer. Evidence is given to indicate that this effect cannot be accounted for using the “melt structural heterogeneity” mechanism proposed for a different system by Andtrianova.