The Rheological Design of Aliphatic Polyketone Terpolymer Blends with Polyester Thermoplastic Elastomer

Abstract

The polyketone terpolymer of ethylene, propylene, and carbon monoxide (EPCO) was melt-mixed with a polyester thermoplastic elastomer (HY) in an internal mixer on rheological basis. The viscosity ratio as well as composition of two polymers had a significant effect on the morphology and mechanical properties of EPCO/HY blends. EPCO exhibited shear-thinning behavior and HY showed Newtonian behavior at the melt mixing temperature. Up to the HY content of 20 wt%, the blend morphology followed the Taylor's rule; as shear rate increased, the viscosities of two polymers merged and the size and its distribution of dispersed HY domains decreased. The EPCO blend with 20 wt% HY exhibited the highest notched Izod impact strength that was further increased as the mixing rate was increased. The impact strength of the blends, however, decreased abruptly and the mixing rate had little effect on the blend morphology if the HY content exceeded 30 wt%. Unlike notched Izod impact strength, the tensile properties and toughness of the blends decreased as the HY content increased.