TENSILE AND FATIGUE PROPERTIES OF SEGMENTED POLYETHER POLYURETHANES AND APPLICATION TO BLOOD PUMP DESIGN.

Mechanical characteristics required of the diaphragm material are flexibility, high strength and long-term durability. Stability of mechanical properties for the duration of applications is also very important for the long-term guarantee of the performance of implant devices. Although we have much blood compatibility test data and tensile test data on many kinds of elastomeric candidates, almost no basic information is available on their fatigue properties. In selecting a diaphragm material for our LVAD pumps, we carried out a series of integrated studies on the tensile and fatigue properties of several elastomeric polymers such as Biomer, Avcothane 51, Toyobo TM5, Texin MD85A (Mobay) and Hexsyn (Goodyear). Preliminary experiments by the tensile and fatique tests in air at room temperature indicated that Biomer and Toyobo TM5 have more favorable characteristics for our LVAD pump diaphragm than the other polymers.