Kusy R P, Whitley J Q
J Biomed Mater Res. 1983 May;17(3):411-25. doi: 10.1002/jbm.820170303.
The controlled failure of polypropylene (PP) sutures is studied via creep rupture tests. From plots of log time (tB) vs. stress (sigma), linear relationships are generated over the failure times of 1-1000 h. Results show that as a function of stress, the time dependence varies with irradiation dose (15, 20, 25, and 50 Mrad), irradiation atmosphere (air and vacuum), suture diameter (7-0, 6-0, 5-0, and 4-0), and test temperature (26 and 37 degrees C). For a given stress, the time to failure is least for the greatest dose in the presence of air and at the highest temperature. When suture loops are wrapped around a small wire sheave, however, failure occurs in the largest suture as much as two decades sooner than the smallest suture studied. Within the limitations stated herein, they are independent of test method, loop diameter, aging, and humidity. Consequently, after irradiation in vacuum and postirradiation heat treatment, the processed material may be stored at room temperature for at least 1 month. Such materials are advocated when the time release of a dental or medical device is required, for example, in the self-activating cleft palate appliance.
通过蠕变断裂试验研究了聚丙烯（PP）缝线的可控失效情况。从对数时间（tB）对应力（sigma）的曲线图中可以看出，在1 - 1000小时的失效时间内呈现出线性关系。结果表明，作为应力的函数，时间依赖性随辐照剂量（15、20、25和50兆拉德）、辐照气氛（空气和真空）、缝线直径（7 - 0、6 - 0、5 - 0和4 - 0）以及测试温度（26和37摄氏度）而变化。对于给定的应力，在空气中且温度最高时，失效时间在最大剂量下最短。然而，当缝线环缠绕在一个小线轮上时，最大的缝线出现失效的时间比所研究的最小缝线早多达二十年。在本文所述的限制范围内，它们与测试方法、环直径、老化和湿度无关。因此，在真空中辐照并进行辐照后热处理后，加工后的材料可在室温下储存至少1个月。当需要牙科或医疗设备的缓释时，例如在自激活腭裂矫治器中，提倡使用此类材料。
