Zhao Q, Casas-Bejar J, Urbanski P, Stokes K
Physiological Research Laboratories, Medtronic Inc., Minneapolis, Minnesota 55448, USA.
J Biomed Mater Res. 1995 Apr;29(4):467-75. doi: 10.1002/jbm.820290406.
Environmental stress cracking (ESC) in polyetherurethanes has been demonstrated in animal models. However, duplication of this phenomenon in vitro has been a challenge. The glass wool-H2O2/CoCl2 test system was designed to provide oxidation components found in vivo, i.e., hydroxyl radical (HO.), molecular oxygen (O2), and superoxide (O2-.) required for auto-oxidation of polyetherurethanes. The in vitro test is not only reliable in duplicating the characteristics of in vivo stress cracking in polyetherurethanes at 37 degrees C, but also accelerates ESC as much as seven times. The test results on several types of polyurethanes showed that Tecothane 80A was as vulnerable to biodegradative stress cracking in vitro as Pellethane 2363-80A, while the new generation of polyurethanes, Corethane, demonstrated great resistance against stress cracking.
聚醚聚氨酯中的环境应力开裂（ESC）已在动物模型中得到证实。然而，在体外复制这一现象一直是个挑战。玻璃棉-H₂O₂/CoCl₂测试系统旨在提供体内发现的氧化成分，即聚醚聚氨酯自动氧化所需的羟基自由基（HO·）、分子氧（O₂）和超氧阴离子（O₂⁻·）。该体外测试不仅在37℃下复制聚醚聚氨酯体内应力开裂特征方面可靠，而且能将ESC加速多达七倍。对几种类型聚氨酯的测试结果表明，Tecothane 80A在体外对生物降解应力开裂的敏感性与Pellethane 2363-80A相同，而新一代聚氨酯Corethane表现出对应力开裂的强大抗性。
