Characterization of the dynamic properties of binary polypropylene blends via the hysteresis measurement method

Due to the poor impact behavior of polypropylene (PP) at low temperatures, blending PP with an elastomeric phase is a common way to improve some of th e characteristic quantities. The property profile of thermoplastic elastome rs strongly depends on the content of the elastomeric component. For applic ations under dynamic loading conditions, the corresponding material behavio r is of importance. In order to reduce long testing times with constant amp litude loading, the hysteresis measurement method, which evaluates the hyst eresis loop and makes use of a stepwise load increase procedure (SLIP), was developed. Binary blends based on PP were compounded with either ethylene- propylene-dien-rubber (EPDM), metallocene polymerized polyethylene (mPE), o r styrene-ethylene-butylene-styrene block copolymer (SEBS) as the elastomer ic phase. Static and dynamic tests under tensile and pressure conditions we re performed in order to evaluate the influence of the type of elastomeric phase on the properties of these blends. It is shown how the hysteresis mea surement method can be used to determine dynamic load limits for the applic ation of these blends and of other polymers. Some properties improved sligh tly when using mPE.