Thermoplastic polyurethane--the material used for the Erlanger silver catheter.

The Erlanger silver catheter consists of a thermoplastic polyurethane elastomer (TPU). To achieve an antimicrobial effect, silver particles at a concentration of 0.5-1.0% by weight are incorporated into the basic material. The good mechanical properties were shown to remain present after the incorporation of the silver. The characteristic mechanical data of blends made of a soft and a hard TPU type approximated closely to a linear relationship with the ratio of the mixture. The buckling stability of catheters as a function of their cross section could be described by Euler's formula. This enables the buckling stability to be calculated when material constants and catheter geometry are known.