Conductive polythioethers are widely used sealants where both environmental and electromagnetic radiation sealing is required. The aging behavior of these sealants is of critical interest in industry since hardware built using these sealants may need to function and the sealant provide a satisfactory seal for years, if not decades, after the hardware is initially built and the sealant initially applied. Accelerated oven aging data at 65, 75 and 85 °C for time periods ranging from 73 to 1773 h on two commercial conductive polythioether sealants are discussed. Adhesion efficacy is quantified by changes in lap shear per ASTM D1002. Electromagnetic interference sealing efficacy is quantified by changes in volume resistivity per MIL-STD-883. The two sealants show similar aging behavior for conductivity in that volume resistivity fell dramatically upon accelerated oven aging. The lap shear increased significantly for only one of the two sealants, indicating that the supplier recommended cure protocol for that sealant did not lead to full cure. Instead, the cure progressed further during accelerated oven aging. This caused the lap shear to increase up to around 40% as compared to unaged samples. The aging temperature was limited to 85 °C out of concern that a higher temperature may change the degradation mechanism from that prevailing at room temperature, RT [23C], which can lead to erroneously high life predictions. The aging time was limited to 1773 h [74 days] due to practical, equipment and experimental constraints. It is expected that the adhesive and conductive efficacy after 30 years at 23 °C should be no worse [and perhaps significantly better] than upon initial build.

导电聚硫醚广泛用于需要环境和电磁辐射密封的密封剂。这些密封剂的老化行为在工业中具有重要意义，因为使用这些密封剂构建的硬件可能需要发挥作用，并且在最初构建硬件和最初应用密封剂后，密封剂可以提供令人满意的密封多年，如果不是几十年的话。讨论了两种商用导电聚硫醚密封胶在 65、75 和 85°C 下的加速烘箱老化数据，时间范围为 73 至 1773 小时。根据 ASTM D1002，通过搭接剪切力的变化来量化粘合效果。根据 MIL-STD-883，通过体积电阻率的变化来量化电磁干扰密封效果。这两种密封剂的电导率老化行为相似，因为在加速炉老化时体积电阻率急剧下降。两种密封剂中只有一种的搭接剪切显着增加，表明供应商推荐的该密封剂的固化方案没有导致完全固化。相反，在加速烘箱老化期间固化进一步进行。与未老化的样品相比，这导致搭接剪切增加了约 40%。老化温度被限制在 85 °C，因为更高的温度可能会改变室温下普遍存在的降解机制，RT [23C]，这可能导致错误的高寿命预测。由于实际、设备和实验的限制，老化时间被限制在 1773 小时 [74 天]。