Studies of poly(ether)urethane pacemaker lead insulation oxidation

Abstract

Published reports suggest that silver ions may catalyze the oxidation of poly‐(ether)urethane soft‐segments resulting in the failure of urethane insulations of specific models of pacemaker leads. Attempted oxidation of soft‐segment models, poly‐(tetra‐methylene ether)glycols, by silver nitrate has shown that metal‐ion catalyzed oxidative‐reduction (MICOR) does not adequately explain observed failures unless antioxidants are removed in process. Such cracking can, however, be explained in terms of a metal ion enhanced environmental stress cracking.