ABSTRACT

Conventional test methods to evaluate the water resistance of adhesive joints are time-consuming. To reduce experimental time, open-faced specimens have been proposed. Numerical analysis indicated that the water absorption of an open-faced specimen was 3000 times faster than that of a conventional closed specimen. The strength of the interface between the adhesive and the adherend of the open-faced specimen was measured using the interfacial cutting method in this research. The resultant strength decreased with respect to immersion time in water, and this trend accelerated with an increase in the water temperature. When water was absorbed at temperatures below the glass transition temperature (T_g) of the adhesives, the strength was constant at 80–90% of the initial value in the first stage, and it decreased proportionally with logarithmic immersion time in the following stage. At water absorption above T_g, the interfacial strength initially proportionally decreased with the logarithmic immersion time. After the initial absorption, the slopes changed, and the strength slowly decreased. After further immersion for 59 days at 87°C, a sharp decrease in strength occurred. The reducing behaviour of the interfacial strength fitted the Arrhenius plot, which provided the estimated time to reach a specific strength by water immersion.

摘要

评估粘合接头防水性的传统测试方法非常耗时。为了减少实验时间，有人提出了开面试样。数值分析表明，开放面试样的吸水率比传统封闭试样的吸水速度快3000倍。在本研究中，使用界面切割方法测量了粘合剂与开面试样的被粘物之间的界面强度。所得强度随浸入水中的时间而降低，并且这种趋势随着水温的升高而加速。当水在低于玻璃化转变温度 ( T _g)，第一阶段强度恒定为初始值的 80-90%，并在随后的阶段随着对数浸渍时间成比例下降。在吸水率高于T _{g 时}，界面强度最初与对数浸没时间成正比。初次吸收后，坡度发生变化，强度慢慢下降。在 87°C 下进一步浸泡 59 天后，强度急剧下降。界面强度的降低行为符合 Arrhenius 图，它提供了通过水浸达到特定强度的估计时间。