| 초록 |
The probe lens, which made of RTV silicone and a polyether urethane (PEU), for medical ultrasonic transducer was put to various environmental conditions to measure chemical attack resistance, soak-dry resistance and heat resistance. The chemical aging was carried out in three disinfectant solutions (i.e, ethanol, isopropyl alcohol (IPA) and Cidex OPA) at 23 ℃ for 480 hours, respectively. For the heat aging, the probe lens was aged at 70 ℃ and 50 % relative humidity for 480 hours. The soak-dry aging was performed for nine cycles (one cycle consists of the heat aging for 24 hours and then the chemical aging in IPA for 24 hours). It is clearly observed that the density of PEU decreases after chemical aging in IPA and soak-dry resistance tests, while the weight increasing ratio increases in these tests. In addition, the relative acoustic impedances of RTV silicone and PEU were more remarkably decreased in immersion of Cidex OPA and IPA respectively compared to those of the other agings. |
