シリコンカテーテルの劣化過程の力学特性

抄録

In the present investigation, we have examined the mechanical properties of unused silicone catheters(CAPD catheter). They were experimentally exposed to 10% solution of popidon-iodine liquid (drug) in order to comparatively evaluate changes in mechanical properties of substance. The static test was performed with an Instron-type universal testing machine. The dynamic viscoelastic properties were measured by a viscoelastic spectrometer. We conducted an examination over several periods of time, based on fracture load, ultimate strength, dynamic stiffness, dynamic elastic modulus and phase-lag (tanδ) of silicone catheter. The catheters were immersed in the drug at 18°C, 37°C, and 60°C. The result showed that the change in the viscoelastic properties begun during 3 days of immersion at 37°C and 60°C. For the specimen immersed at 18°C, a different time course of stiffness and dynamic elastic modulus from 3 days to 1 week was observed as compared with the result for the specimens immersed at 37°C and 60°C. However the trend was similar at 2 weeks for all the temperatures. Static test result also demonstrated that ultimate strength and fracture load were highly significant between immersed temperature 20°C, 37°C groups and 60°C group. In clinical case, stiffness was higher and tanδ was lower than control within body site, while stiffness was lower and tanδ was higher than control without body site.