K. Zhang, Diamond Innovations, Columbus, OH; M. Wallick, Zimmer, Inc., Warsaw, IN; H. Brinkerhuff, Zimmer, Warsaw, IN
Polyurethanes have been used as biomaterials due to their versatile material properties and good biocompatibility. The broad variation of polyurethane chemistry and structures offers many promising biomaterial applications including those in orthopaedics. Examples include, but not limited to, spinal implants such as DYNESYS® from Zimmer Spine, and tissue engineering scaffolds for soft and connection tissues. The objective of this study is to evaluate and investigate the tensile dynamic mechanical and tensile short-term creep properties of five currently available medical-grade polyurethane elastomers (Elast-Eon E2A from AorTech, Pellethane 2363 80A from Dow Chemical, Bionate 80A UR, Bionate 90A S and Carbosil 20 90A all from Polymer Technology Group) using a dynamic mechanical analyzer (TA Instruments DMA model 2980) for potential spinal and orthopaedic applications.
Following the ASTM 5026-01 and 1640-04, the tensile dynamic mechanical properties and the tensile short-term static creep of five medical-grade polyurethane (PU) elastomers were studied. The specimens were injection molded, and then tested before and after gamma sterilization. Results showed that (1) both the storage moduli and the damping (tan delta) of the five PU increase with the frequency; (2) gamma sterilization increases the storage moduli and decreases the creep strain of the five PU; (3) among the five PU samples, Elast-Eon E2A has the highest storage modulus, and the lowest creep strain under a load of 0.1 MPa; and (4) the Tg of the five PU can be determined by the peak temperature of the loss modulus curve.
Summary: The tensile dynamic mechanical properties and the tensile short-term static creep of five medical-grade polyurethane (PU) elastomers (Elast-Eon E2A from AorTech, Pellethane 2363 80A from Dow Chemical, Bionate 80A UR, Bionate 90A S and Carbosil 20 90A all from Polymer Technology Group)were studied.
